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March 8, 2021
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https://www.sciencedaily.com/releases/2021/03/210308111904.htm
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'Island of Rats' recovers
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Along the western edge of Alaska's Aleutian archipelago, a group of islands that were inadvertently populated with rodents came to earn the ignominious label of the "Rat Islands." The non-native invaders were accidentally introduced to these islands, and others throughout the Aleutian chain, through shipwrecks dating back to the 1700s and World War II occupation. The resilient rodents, which are known to be among the most damaging invasive animals, adapted and thrived in the new setting and eventually overwhelmed the island ecosystems, disrupting the natural ecological order and driving out native species.
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A coordinated conservation effort that removed the rats from one of the islands formerly known as Rat Island has become a new example of how ecosystems can fully recover to their natural state in little more than a decade. The ecological rebound at newly named Hawadax Island (a return to the original Aleut name meaning "the island over there with two knolls") extended from land to the island's interconnected marine community. Results of a study published in "We were surprised that the level of recovery unfolded so quickly -- we thought it could be longer," said Carolyn Kurle, an associate professor in the UC San Diego Division of Biological Sciences Section of Ecology, Behavior and Evolution and lead author of the new study, which includes researchers from UC Santa Cruz, Island Conservation, the U.S. Fish and Wildlife Service and The Nature Conservancy.Kurle has taken part in research expeditions to more than 35 of the islands in the Aleutian chain. She and her colleagues conducted surveys at Hawadax in 2008 when the invasive rodents dominated the island ecosystem. As a new, direct predator to native island species, the rats unleashed a cascade of disruption for the island's food chain. They preyed upon shore bird eggs and chicks, which nearly wiped out the island's breeding shorebird population. Without birds consuming herbivorous seashore invertebrates such as snails and limpets, the island's intertidal plant-eaters flourished, significantly driving down the abundance of the marine kelp.To reverse these effects, a coordinated conservation strategy to save the native species on Hawadax removed the rats in 2008. The effort presented a rare case in which researchers were able to compare ecosystem data from surveys during rat dominance with a recovering ecosystem five years later and a fully recovered system after 11 years."You don't often get the opportunity to return to a remote location and collect data after the fact," said Kurle, who noted that the researchers also compared the survey data with naturally balanced ecosystems on neighboring islands that had never been occupied with rats. "Sometimes it's hard to say that a conservation action had any sort of impact, but in this particular case we took a conservation action that was expensive and difficult, and we actually demonstrated that it worked. But we didn't expect it to be so fast."With the rats removed at Hawadax, the seabirds returned and are again consuming the seashore invertebrates, which has allowed the recovery and rebound of the kelp community."Invasive rats are almost always direct predators of native animals when they become introduced on islands," said Kurle. "So when the birds returned it led to an entirely different structure in the marine community on this island. It now has a structure that more closely resembles what we observe on islands that have never had rat invaders."The researchers say more studies that focus on understanding and measuring both direct and indirect impacts of invaders, and how inter-connected communities respond following removal of those impacts, are needed to underscore the broad conservation successes associated with invasive species eradication, especially on islands."This study both confirms the profound impacts of introduced species like rats across entire sensitive island ecosystems while at the same time demonstrating the remarkable conservation benefits of their removal," said Donald Croll, study co-author and professor in the Ecology and Evolutionary Biology Department at UC Santa Cruz.The research was funded in part by the U.S. Fish and Wildlife Service and the National Fish and Wildlife Foundation and the eradication was conducted by Island Conservation, the U.S. Fish and Wildlife Service and The Nature Conservancy.
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Animals
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March 8, 2021
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https://www.sciencedaily.com/releases/2021/03/210308111847.htm
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Paw hygiene no reason to ban assistance dogs from hospitals
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Over 10,000 people in Europe use an assistance dog; think of guide dogs for people with a visual impairment, hearing dogs for people with a hearing impairment, medical response service dogs and psychiatric service dogs.
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According to a UN-agreement and the Dutch law, these dogs are welcome in stores, hospitals and other public places. However, in practice, many assistance dog users and their dogs are regularly refused entry. In the Netherlands, four out of five assistance dog users indicate that they regularly experience problems with this.Often, hygiene reasons are given as the main argument for refusing entry to assistance dogs. Research by Utrecht University now shows that the paws of assistance dogs are cleaner than the shoe soles of their users, and thus, paw hygiene is no reason to ban assistance dogs from hospitals.To investigate this, Jasmijn Vos, Joris Wijnker and Paul Overgaauw of Utrecht University's Faculty of Veterinary Medicine took samples from the paws of 25 assistance dogs and the shoe soles of their users. For comparison, they also investigated an equally large group of pet dogs and their owners. Vos and her colleagues examined the samples for poop bacteria (Enterobacteriaceae), which are very common outdoors, and for an important diarrheal bacteria (Clostridium difficile)."The dogs' paws turned out to be cleaner than the soles of their shoes," says Jasmijn Vos, Masters student at Utrecht University. "This makes the hygiene argument that is often used to ban assistance dogs from public locations invalid." Moreover, the diarrheal bacteria did not occur on the dogs' paws whatsoever, and only once on a shoe sole.Dutch assistance dog users were also surveyed about their experiences. 81% are still regularly refused entry to public places with their dog, even though this is prohibited by law. This is mainly down to lack of knowledge on the part of the person refusing entry: lack of knowledge on what an assistance dog is, how it can be recognised, and about the rules of law.The study also shows that assistance dog users constitute only a small fraction of the total number of patients in Dutch hospitals. Should they decide to bring their assistance dog to the hospital, or elsewhere, this should be made possible; assistance dogs are usually well trained and are no more of a hygiene hazard than people!
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Animals
| 2,021 |
March 5, 2021
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https://www.sciencedaily.com/releases/2021/03/210305080118.htm
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Chimpanzees without borders
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Researchers from the Pan African Programme: The Cultured Chimpanzee (PanAf) at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) and a team of international researchers, collected over 5000 fecal samples from 55 sites in 18 countries across the chimpanzee range over 8 years. This is by far the most complete sampling of the species to date, with a known location of origin for every sample, thus addressing the sampling limitations of previous studies. "Collecting these samples was often a daunting task for our amazing field teams. The chimpanzees were almost all unhabituated to human presence, so it took a lot of patience, skill and luck to find chimpanzee dung at each of the sites," explains Mimi Arandjelovic, co-director of the PanAf and senior author of the study.
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Jack Lester, first author of the study, explains: "We used rapidly-evolving genetic markers that reflect the recent population history of species and, in combination with the dense sampling from across their range, we show that chimpanzee subspecies have been connected, or, more likely, reconnected, for extended periods during the most recent maximal expansion of African forests."So although chimpanzees were separated into different subspecies in their distant past, prior to the rise of recent anthropogenic disturbances, the proposed subspecies-specific geographic barriers were permeable to chimpanzee dispersal. Paolo Gratton, co-author of the study and researcher at the Università di Roma "Tor Vergata" adds: "It is widely thought that chimpanzees persisted in forest refugia during glacial periods, which has likely been responsible for isolating groups of populations which we now recognize as subspecies. Our results from fast-evolving microsatellite DNA markers however indicate that genetic connectivity in the most recent millennia mainly mirrors geographic distance and local factors, masking the older subspecies subdivisions."Furthermore, "these results suggest that the great behavioural diversity observed in chimpanzees are therefore not due to local genetic adaptation but that they rely on behavioural flexibility, much like humans, to respond to changes in their environment," notes Hjalmar Kuehl, co-director of the PanAf and researcher at the German Centre for Integrative Biodiversity Research (iDiv).The team also observed signals of reductions in diversity at some sites that appeared to be associated with recent anthropogenic pressures. In fact, at some locations PanAf teams visited no, or few, chimpanzees were detected despite recordings of their presence within the last decades. "Although not unforeseen, we were disheartened to already find the influence of human impacts at some field sites where genetic diversity was markedly lower than what we expected," says Jack Lester.These results highlight the importance of genetic connectivity for chimpanzees in their recent history. "Every effort should be made to re-establish and maintain dispersal corridors across their range, with perhaps special attention to trans-national protected areas," notes Christophe Boesch, co-director of the PanAf and director of the Wild Chimpanzee Foundation. Chimpanzees are known to be adaptable to human disturbance and can survive in human-modified landscapes, however, habitat loss, zoonotic diseases, bushmeat and pet trades are all threats to chimpanzee survival. These results warn of future critical impacts on their genetic health and viability if habitat fragmentation and isolation continue unabated.
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Animals
| 2,021 |
March 4, 2021
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https://www.sciencedaily.com/releases/2021/03/210304145455.htm
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Animal aggression depends on rank within social hierarchies
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Humans and animals alike constantly size up one another. In the workplace, a new employee quickly learns which coworkers are the most respected -- and therefore hold more power. Big brothers boss around little brothers. In nature, a dominant male chimpanzee fights off would-be intruders. Even fish and octopi interact within social hierarchies.
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These pecking orders have been studied within the behavioral ecology world for almost 100 years. How individuals interact can affect access to food and mates -- even survival -- and insights into those behaviors can lead to better management of threatened and endangered populations. But few studies have explored what the animals that live within these dominance hierarchies actually know about each other. The more animals know about each other, the more they may be able to optimize their aggression. New research, published March 3 in Using a new computational method, the researchers examined existing data on aggression -- the earliest from a 1934 pigeon study -- in 172 social groups across 85 species in 23 orders, looking for social dominance patterns. They found three main aggression strategies employed by individuals: simply fighting any lower-ranked opponents; specializing in fighting "close competitors" ranked just below themselves; and bullying opponents ranked much lower. The majority of the groups fell into the first category, where aggression could be explained by animals following a basic dominance hierarchy, but several groups used the more information-rich close competitors or bullying strategies to fine-tune their choice of opponents.Rank clearly influences how one individual treats another, says biologist Elizabeth Hobson, the lead author of the study. She is currently an Assistant Professor at the University of Cincinnati and was formerly a Complexity Postdoctoral Fellow at the Santa Fe Institute, where she conducted much of the research."What we're able to do with our computational approach is to get new insight into how animals are managing conflict within the groups, and the kind of information that informs those decisions," she says. Simon DeDeo of Carnegie Mellon University and the Santa Fe Institute and Dan Mønster of Aarhus University in Denmark also contributed to the work.Some of the results took the team by surprise. For example, it turns out that pronghorn -- a speedy North American ungulate prized for its graceful gait -- can be bullies. "They look so cute, right?" says Hobson. "You don't expect them to have a bullying strategy in their group."Another unexpected insight was that social dominance patterns can vary from group to group within the same species. For example, one group of African elephants behave according to a close competitor hierarchy, while another group exhibits bullying behavior.It's unclear why dominance strategies sometimes differ among groups, but this and other studies suggest that they can change according to the context in which individuals interact.For example, "it may be that you have near rivals, so you might have to have conflict to sort that out," DeDeo says.Hobson says she hopes the study will inspire other researchers to look at how social information is used within and across species. This could provide a foundation for answering even bigger questions about how social complexity arises in animals, and how animals evolved the cognitive skills to enact these social dominance patterns.
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Animals
| 2,021 |
March 4, 2021
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https://www.sciencedaily.com/releases/2021/03/210304145425.htm
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Could catnip become the new insect repellent?
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New collaborative research from Northwestern University and Lund University may have people heading to their backyard instead of the store at the outset of this year's mosquito season.
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Often used as an additive for cat toys and treats due to its euphoric and hallucinogenic effects on cats, catnip has also long been known for its powerful repellent action on insects, mosquitoes in particular. Recent research shows catnip compounds to be at least as effective as synthetic insect repellents such as DEET.But until now, the mechanism that triggered insects' aversion to this common member of the mint family was unknown. In a paper to be published March 4 in the journal "Catnip and its active ingredient, Nepetalactone, have been used for millennia to ward off insect pests, at least since the time of Pliny the Elder," said Marcus C. Stensmyr, associate professor at Lund University and co-corresponding author. "But why Catnip is so potent on such a broad range of insect species has remained unknown."Traditional approaches to mosquito control involved insecticides, but those eliminate other insect species as collateral damage. Modern formulations of insect repellents such as DEET target mosquito odor and taste receptors, rendering the insect incapable of recognizing the chemical cues that signal a human prey."We discovered that Catnip and its active ingredient Nepetalactone activate the irritant receptor TRPA1, an ancient pain receptor found in animals as diverse as flatworms, fruit flies and humans," said Marco Gallio, an associate professor of neurobiology in the Weinberg College of Arts and Sciences. "We now think Catnip is so aversive to so many insect species because it activates this widespread irritant receptor."In previous work, the Gallio Lab and others demonstrated that humans, insects and many other animal species possess a version of the transient receptor potential ankyrin 1 (TRPA1) ion channel, a protein best known as the "wasabi receptor" that senses environmental irritants like pain and itch."What is particularly interesting is that, unlike wasabi or garlic compounds that also activate these receptors in humans, catnip appears to selectively activate the insect receptor," Gallio said. "This explains why humans are indifferent to it, and provides a serious advantage for its use as a repellent."Why cats are so attracted to catnip is an entirely different story and one that is not entirely understood. Research indicates this may be due to an unusual interaction between one of catnip's active ingredients and a molecular component present in the reward system of the cat brain."Mosquitos, in particular those that act as vector for disease, are becoming a bigger problem as climate change creates attractive conditions for them farther north and south of the equator," Stensmyr said. "Plant-derived compounds represent a new emerging approach to developing insect repellents, as plants have long known how to protect themselves from insect pests."Gallio added that plant-derived repellants are often available at a much lower cost and are easier to obtain. Catnip's accessibility could have major implications in developing countries where mosquito-borne diseases are a huge problem.The Gallio lab at Northwestern studies the sensory systems of the common Lab fruit fly Drosophila, including the mechanisms that control the responses to external temperature and pain. Lund's Stensmyr lab mainly focuses on mosquitoes and other insect vectors of human disease.The researchers studied various insect species to better understand how catnip and its active ingredient are working to repel a broad range of insects, while having no irritant effect on humans.To confirm their results, the team ran a range of tests, including offering mosquitoes a blood meal in a dish covered with a nylon sock doused in catnip, experiments involving a wind tunnel, as well as experiments in which volunteers place their hand in a cage with live mosquitos, with or without the protection of a catnip oil rub.Gallio believes that the mechanism they discovered also provides proof of concept for the development of next-generation repellents that exploit the same logic -- selectively targeting the mosquito irritant receptor."This is an entry point to study how this molecule works on the receptor," he said. "Once we understand its chemistry and how it interacts with the receptor, we could design even more powerful and selectively targeted molecules."The team's next project? Finding out how to get rid of the cats that keep chasing them down.
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Animals
| 2,021 |
March 4, 2021
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https://www.sciencedaily.com/releases/2021/03/210304145346.htm
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Social distancing in nature
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Forager ants do it, vampire bats do it, guppies do it, and mandrills do it. Long before humans learned about and started "social distancing due to COVID-19," animals in nature intuitively practiced social distancing when one of their own became sick.
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In a new review published in "Looking at non-human animals can tell us something about what we have to do as a society to make it such that individuals can behave in ways when they are sick that protect both themselves and society as a whole," said Hawley, who is an affiliated faculty member of the Global Change Center and the Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens, which are both housed within the Fralin Life Sciences Institute."Staying home and limiting interactions with others is an intuitive behavioral response when we feel sick -- and one that we see across many types of animals in nature -- but humans often suppress this instinct, at great potential cost to ourselves and our communities, because of pressures to continue working or attending classes even while sick," added Hawley.We all have had that experience of feeling sick. You may feel lethargic and just can't seem to muster the energy to get out of bed or hang out with friends. Although you may not know it, you are practicing a form of social distancing. Since you are not actively trying to avoid people and just rolling with the punches of general malaise, Hawley and co-authors refer to this as "passive social distancing." Of course, this has been observed in non-human species as well.Vampire bats, who feed solely on the blood of other animals, have been well studied because they are highly social, compared to their fruit- and insect-eating bat relatives. Since blood is not nutritional and difficult to find most days, the bats form strong social bonds by sharing food and grooming -- or licking and cleaning each other's fur.To learn more about their "sickness behavior," or how their behavior changes in response to infection, researchers inject the bats with a small piece of cell membrane from a gram-negative bacteria known as lipopolysaccharide. The harmless substance triggers an immune response and their sickness behaviors, such as decreased activity and decreased grooming, without actually exposing them to a pathogen."Passive social distancing in vampire bats is a 'byproduct' of sickness behavior," said Sebastian Stockmaier, who led the review while a Ph.D. student at the University of Texas at Austin, where he is still affiliated. "For instance, sick vampire bats might be more lethargic so that they can divert energy to a costly immune response. We have seen that this lethargy reduces contact with others and that sick vampire bats groom each other less."Mandrills also exhibit grooming behaviors in order to maintain their social bonds, as well as their hygiene. However, these highly social primates are strategic about their social distancing behaviors. Because their grooming behaviors are important to keep their standing in society, they avoid contagious group mates, while occasionally increasing their risk of infection by continuing to groom their infected close relatives.On the other hand, many types of ants practice a form of active social distancing. Over the course of evolution, some ant species have adapted to abandon their tight knit-groups when they are feeling sick. In these cases, the infected individual's self sacrifice is seen as an act of public good to protect the rest of the colony and carry forth the genes that will keep the closely related colony thriving in the future.But there are other cases where the healthy animals go out of their way to exclude sick members from the group or by avoiding contact with them altogether.Bees are another group of social insects whose main goal is to do everything for the greater good of the hive and their queen. So when infected bees are detected within the hive, healthy bees have no choice but to exclude the infected bees -- by aggressively kicking them out of the hive.In other species, the healthy individuals are the ones to leave the group to protect themselves from disease, but often at great cost. To reduce their risk of catching or transmitting a virus, healthy Caribbean spiny lobsters abandon their den when they detect an infected group member in it. Not only does this result in the loss of protection within the group and their den, but they are also exposing themselves to deadly predators in the open ocean. But for them, it is worth this risk to avoid a highly lethal virus.Although not all cases are this severe, reducing one's own social interactions will always incur consequences of some kind, including loss of warmth or having more difficulty finding food.Unfortunately, humans have gotten all too familiar with the costs and benefits of social distancing since the inception of the COVID-19 pandemic. But Hawley says that there are actually many ways in which we have altered our behavior in the midst of disease, without even realizing it."COVID-19 has really highlighted the many ways that we use behavior to deal with disease," said Hawley. "I think that we have all unconsciously used these types of behaviors throughout our lives, and it is only just now coming into focus how important that these behaviors are in protecting ourselves from getting sick."If you are sitting on an airplane and somebody next to you is coughing, you may be less likely to want to talk to them, or you may lean over to one side of your seat. There are so many ways that we are altering our behavior to minimize disease risk and we do it all the time without thinking because it is evolutionarily ingrained in us."As new mutants of the SARS-Cov-2 virus arise, humans will have to continue to wear masks to protect themselves and others and social distance. Unlike animals in nature, humans have developed technology like Zoom to create social connections and bridges while they are physically distancing themselves from others. Hawley also explored virtual technology as a means of compensating for costs of social distancing in humans in a review published in Whether you are a forager ant, a Caribbean spiny lobster, or a human, it is clear that social distancing is a behavior that both benefits us as individuals and the community that connects us with one another. Therefore, we must take care of ourselves and others by practicing a behavior that is more apparent, and more imperative, now than ever before: active social distancing.
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Animals
| 2,021 |
March 4, 2021
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https://www.sciencedaily.com/releases/2021/03/210304133457.htm
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Will climate change outpace species adaptation?
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Many species might be left vulnerable in the face of climate change, unable to adapt their physiologies to respond to rapid global warming. According to a team of international researchers, species evolve heat tolerance more slowly than cold tolerance, and the level of heat they can adapt to has limits.
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In a study published in the The researchers found that first and foremost, a species' thermal tolerance is linked to the current climate where they live. "It's logical that thermal limits mostly match a species' present-day climate but tracing the evolutionary history of thermal limits can reveal how species got to be where they are today," says Sunday, an Assistant Professor in the Department of Biology.The researchers also found that tolerance to cold has evolved much faster than tolerance to heat, particularly in endotherms as compared to ectotherms and plants. Endothermic animals are those that generate metabolic heat to regulate their own body temperature -- for example, mammals and birds -- while ectothermic animals are those that regulate their body temperature using external heat sources, like reptiles, fishes and invertebrates.One cause of this disparity could be that heat tolerance has reached an evolutionary barrier, called an 'attractor,' beyond which further evolution is constrained or selected against. "This is very concerning because it suggests that the vast majority of species will not be able to adapt fast enough to survive the unprecedented rate of contemporary climate change," says co-author Joanne Bennett of Leipzig University and University of Canberra.The results of this study are particularly relevant to conservation management, say the researchers. Protecting and creating areas that provide refuges for biodiversity from upper temperature extremes is a key strategy for conservation managers.
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Animals
| 2,021 |
March 3, 2021
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https://www.sciencedaily.com/releases/2021/03/210303142524.htm
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Tiny computers reveal how wild bats hunt so efficiently
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An international research team has taken a seat on the back of wild bats to experience their world through echoes recorded on-board the bats by 3-gram computers.
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In a new paper published in "We experienced the world through the ears of the bats by recording their echoes directly on-board while they were hunting for insects at night," said Dr. Laura Stidsholt, postdoc at Aarhus University and leading author of the study.The tags recorded the echolocation calls and the movement of each bat in three dimensions, but most importantly, the echoes returning from their environment during one full night of foraging. This allowed the research team to tap into the sensory scenes of a hunting animal."We wanted to use the tags to find out how bats control what they "see" when they hunt tiny insects on the wing on superfast timescales. We used the sound recordings to find and track echoes from prey and vegetation, and to our surprise, we found that the bats are guided by extremely weak prey echoes that would be like a whisper to us," said Dr. Laura Stidsholt.The bats themselves control the strength of their returning echoes by calling louder or weaker. So why would they choose these weak echoes, if they could increase the levels by calling louder?To answer this, the researchers quantified the volume of air in which bats could potentially detect an echo for each echolocation call. The bats controlled the size of these sensory volumes by adjusting the strength of their calls."We found that hunting bats narrow their sensory volumes by more than a thousand times to only focus on the prey and thereby reduce the clutter from other echoes. It's like an acoustic version of a tunnel vision that briefly makes their world much simpler," said Dr. Holger Goerlitz of Max Planck Institute of Ornithology, a co-author of the study. He continued:"The weak prey echoes might therefore be a consequence of the small sensory volumes shaped to hunt close to background clutter."To protect these weak echoes from interference, the research team also showed that the bats used their flight patterns to separate the prey echoes from the background e.g. by flying parallel to trees."When the bats are hunting, they stay at least a prey detection distance away from the vegetation. We think they do this to avoid masking of the weak prey echoes by the loud echoes from vegetation. By continually adjusting both their flight patterns and their sensory volumes during the hunt, the bats simplify the information they need to process," said senior author Professor Peter Teglberg Madsen of Aarhus University.Peter Teglberg Madsen suggests that the bats dedicate their attention and brain to the most essential information -- getting their next meal -- and that this might be one of the reasons that bats are such efficient hunters.The miniature tags were designed and developed by Associate Professor Mark Johnson at Aarhus Institute of Advanced Sciences."It was a real challenge to make a computer so small that it could work on a flying bat and still be sensitive enough to pick up these weak sounds," said Mark Johnson.Echolocating bats account for 20 percent of all mammal species and play important roles in ecosystems across the planet."We think that this strategy has expanded the niches available to look for insects and is one of the reasons that bats have become such versatile hunters, but we don't know if they are versatile enough to cope with all the changes humans are making to the environment," said Professor Peter Teglberg Madsen.
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Animals
| 2,021 |
March 3, 2021
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https://www.sciencedaily.com/releases/2021/03/210303142437.htm
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Prehistoric killing machine exposed
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Judging by its massive, bone-crushing teeth, gigantic skull and powerful jaw, there is no doubt that the Anteosaurus, a premammalian reptile that roamed the African continent 265 to 260 million years ago -- during a period known as the middle Permian -- was a ferocious carnivore.
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However, while it was previously thought that this beast of a creature -- that grew to about the size of an adult hippo or rhino, and featuring a thick crocodilian tail -- was too heavy and sluggish to be an effective hunter, a new study has shown that the Anteosaurus would have been able to outrun, track down and kill its prey effectively.Despite its name and fierce appearance, Anteosaurus is not a dinosaur but rather belongs to the dinocephalians -- mammal-like reptiles predating the dinosaurs. Much like the dinosaurs, dinocephalians roamed and ruled the Earth in the past, but they originated, thrived, and died about 30 million years before the first dinosaur even existed.The fossilised bones of Dinocephalians are found in many places in the world. They stand out by their large size and heavy weight. Dinocephalian bones are thick and dense, and Anteosaurus is no exception. The Anteosaurus' skull was ornamented with large bosses (bumps and lumps) above the eyes and a long crest on top of the snout which, in addition to its enlarged canines, made its skull look like that of a ferocious creature. However, because of the heavy architecture of its skeleton, it was previously assumed that it was a rather sluggish, slow-moving animal, only capable of scavenging or ambushing its prey, at best."Some scientists even suggested that Anteosaurus was so heavy that it could only have lived in water," says Dr Julien Benoit of the Evolutionary Studies Institute at the University of the Witwatersrand (Wits University).By carefully reconstructing the skull of the Anteosaurus digitally using X-ray imaging and 3D reconstructions, a team of researchers investigated the internal structures of the skull and found that the specific characteristics of its brain and balance organs were developed in such a way that it was everything but slow-moving."Agile predators such as cheetahs or the infamous Velociraptor have always had a very specialised nervous systems and fine-tuned sensory organs that enable them to track and hunt down prey effectively," says Benoit. "We wanted to find out whether the Anteosaurus possessed similar adaptations."The team found that the organ of balance in Anteosaurus (its inner ear) was relatively larger than that of its closest relatives and other contemporaneous predators. This indicates that Anteosaurus was capable of moving much faster than its prey and competitors. They also found that the part of the brain responsible for coordinating the movements of the eyes with the head was exceptionally large, which would have been a crucial trait to ensure the animal's tracking abilities."In creating the most complete reconstruction of an Anteosaurus skull to date, we found that overall, the nervous system of Anteosaurus was optimised and specialised for hunting swiftly and striking fast, unlike what was previously believed," says Dr Ashley Kruger from the Natural History Museum in Stockholm, Sweden and previously from Wits University."Even though Anteosaurus lived 200-million years before the famous dinosaur Tyrannosaurus rex, Anteosaurus was definitely not a 'primitive' creature, and was nothing short of a mighty prehistoric killing machine," says Benoit.
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Animals
| 2,021 |
March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302212007.htm
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Cutting-edge analysis of prehistoric teeth sheds new light on the diets of lizards and snakes
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New research has revealed that the diets of early lizards and snakes, which lived alongside dinosaurs around 100 million years ago, were more varied and advanced than previously thought.
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The study, led by the University of Bristol and published in There are currently some 10,000 species of lizards and snakes, known collectively as squamates. It was originally understood their great diversity was acquired only after the extinction of dinosaurs, but the findings demonstrate for the first time that squamates had modern levels of dietary specialisation 100 million years ago.Fossils of lizards and snakes are quite rare in the Mesozoic, the age of dinosaurs and reptiles. This could simply be because their skeletons are small and delicate so hard to preserve, or it could show that lizards and snakes were in fact quite rare in the first half of their history.The researchers studied 220 Mesozoic squamates, comprising lizards, snakes and mosasaurs, a group of extinct large marine reptiles. They measured their jaws and teeth and allocating them to dietary classes by comparison with modern forms. Some have long peg-like teeth and feed on insects, others have flat teeth used for chopping plant food. Predators have sharp, pointed teeth, and snakes have hooked teeth to grasp their prey.All the fossil forms were allocated to one of eight feeding categories, and then their diversity through time was assessed. To the researchers' surprise, it turned out that the rather sparse Cretaceous squamates included examples of all modern feeding strategies."We don't know for sure how diverse squamates were in the Cretaceous," said lead author Dr Jorge Herrera-Flores, who is now a Research Fellow at the National Autonomous University of Mexico."But we do know they had already achieved the full modern-type diversity of feeding modes by 100 million years ago, in the middle of the Cretaceous. Before that, squamates had already existed for more than 100 million years, but they seemed to be mainly insect-eaters up to that point.""Studying teeth and jaws provides excellent insights into dietary and ecological variety," said co-author Dr Tom Stubbs, Senior Research Associate at the University of Bristol School of Earth Sciences. "Fossil teeth and jaws give us the best insight into squamate evolution in the past. It would be easy to read the fossil record wrongly because of incomplete preservation. However, more fossil finds could only increase the number of feeding modes we identify in the Cretaceous, not reduce them."The explanation for this early rush of dietary experimentation may be related to diversification in other areas. For instance, at this point in the Cretaceous, flowering plants had just begun to flourish and were already transforming ecosystems on land, while squamates also prevailed in the oceans."The Cretaceous Terrestrial Revolution made forests more complex," said co-author Professor Michael Benton, Professor of Vertebrate Palaeontology at the School of Earth Sciences. "The new flowering plants provided opportunities for insects and other creepy crawlies to feed on leaves, pollen and nectar, and to hide in the canopy. It's likely this burst of diversity gave a stimulus to mammals, birds and squamates, all of which diversified about this time, probably feeding on the insects, spiders and other bugs, as well as on the new plant food."The new work does not provide the single reason why squamates are so diverse today -- nearly as diverse as birds. However, it shows that their ancestors had already explored all the likely feeding niches 100 million years ago before the dinosaurs died out.
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Animals
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March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302150112.htm
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Gulf Oil Spill's long-lasting legacy for dolphins
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The Deepwater Horizon disaster began on April 20, 2010 with an explosion on a BP-operated oil drilling rig in the Gulf of Mexico that killed 11 workers. Almost immediately, oil began spilling into the waters of the gulf, an environmental calamity that took months to bring under control, but not before it became the largest oil spill in the history of the petroleum industry.
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Nearly 10 years have passed since then, and the oil slick has long since dispersed. Yet, despite early predictions, area wildlife are still feeling the effects of that oil, and research published in A team of researchers, including UConn Department of Pathobiology Professor and Director of the Connecticut Sea Grant College Program Sylvain De Guise, is part of a network conducting a long-term study on the health of bottlenose dolphins living in Louisiana's Barataria Bay, in the vicinity of the disaster. This population of dolphins includes individuals who lived through the disaster and some born afterwards."We were on the ready and as soon as we could, and in 2011 we initiated a comprehensive health assessment where 60 to 80 people in the field worked together to find and safely pursue a multi-disciplinary, multi-expertise sample collection and study effort to assess the dolphins' health," says De Guise.De Guise explains that after collection, samples were processed in 60 to 80 different specialized labs, and the researchers then regrouped to put the information together. De Guise's research group specializes in studying the immune system, and from the very first set of samples they started to see consistent and abnormal immune responses in the Barataria Bay dolphins, compared with a similar control group of dolphins from Sarasota Bay who were not exposed to oil.For the Barataria Bay dolphins, the researchers observed immune cells called T-cells that were overly responsive to stimulation. The body uses T-cells to respond to a stimulus, or something recognized as foreign. In particular, there were increased numbers of cells called regulatory T cells, or Tregs, which De Guise describes as the cells that help put the brakes on during an immune response to prevent the body from over-responding and doing more harm than good.Despite the elevated numbers, De Guise says they were surprised to find the Barataria Bay dolphin Tregs appear to be functionally defective.In some ways, the immune response can be looked at almost like a relay race, with cells signaling others to respond and join in the effort. In the case of T-helper (Th) cells, important signals called cytokines determine which type of T-helper will be next in the relay, and for the Barataria Bay dolphins, the signals are not relayed as expected."T-helper cells decide which direction your immune system will respond. If you have a pathogen that invades cells, a virus for example, you need a T-helper1 (Th1) response that will destroy the affected cells. If you have a pathogen that does not invade cells, like most types of bacteria, you need to generate antibodies to bind to those bacteria and help eliminate them with a Th2 response," says De Guise.In the lab, the researchers studied the immune cells from both dolphin populations by exposing them to proteins called cytokines which elicit predictable responses from the T-cells. The researchers also exposed T-cells from the control group dolphins to oil to see what would happen. In all samples of T-cells exposed to oil, Th2 responses were exaggerated compared to the control group."We were able to demonstrate that there was a difference in responsiveness between the populations, in both real-life and in-vitro tests which resulted in an increase in Th2 response in the Barataria Bay dolphins," says De Guise.The researchers went one step further by conducting a mouse study to see if a similar immune response could be seen in mice exposed to oil, and they did."The effects on the mouse immune system that we found were strikingly similar to what we saw in the dolphins," says De Guise. "We want to show the likelihood of a cause and effect relationship and add to the weight of evidence that oil impacts the immune system in a way that is very reproducible across species. The changes that we found in the Barataria Bay dolphins is specific to oil and not related to something else."Though the researchers are not sure if the abnormal immune response is due to the initial exposure or continued exposure to oil still present in sediments, De Guise says the result may lead to the dolphins being more susceptible to pathogens like viruses, due to dysfunctional T-reg cells. Only future studies can shed light, and De Guise says now that images of oil slicks are no longer capturing attention, funding is harder to come by.However, for this study, De Guise notes it is very rare to have such a long-term, detailed follow-up on a wild population of animals, and the researchers were very surprised to see effects in a second generation who did not live through the disaster."The outcome of this work is that we are not sure if these effects are reversible or not. The longer we look, they are still around. I think it is the first time we find such evidence across generations in a wild animal population, and that is scary. It raises concern for the long-term recovery of these dolphins," says De Guise. "These are long-lived mammals and, in many ways, not unlike humans who live in the area and depend on natural resources. It is interesting science, but it is very scary."
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Animals
| 2,021 |
March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302130732.htm
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How some animals sense the gritty texture of their food
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There's more to taste than flavor. Let ice cream melt, and the next time you take it out of the freezer you'll find its texture icy instead of the smooth, creamy confection you're used to. Though its flavor hasn't changed, most people would agree the dessert is less appetizing.
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UC Santa Barbara Professor Craig Montell and postdoctoral fellow Qiaoran Li have published a study in The channel, called TMEM63, is part of a class of receptors that appear in organisms from plants to humans. As a result, the new findings could help shed light on some of the nuances of our own sense of taste."We all appreciate that food texture impacts food appeal," said Montell, Duggan and Distinguished Professor in the Department of Molecular, Cellular, and Developmental Biology. "But this is something that we don't understand very well."Li and Montell focused on fruit flies to investigate the molecular and cellular mechanisms behind the effect of grittiness on food palatability. "We found that they, like us, have food preferences that are influenced by this textural feature," Montell said. They devised a taste test in which they added small particles of varying size to sugary food, finding that the flies preferred particles of a specific size.In prior work, Montell and his group have elucidated the nuances at play in the sense of taste. In 2016, they found a channel that enables flies to sense the hardness and viscosity of their food by the movement of the small bristles on their tongue, or labellum. More recently they discovered the mechanisms by which cool temperatures reduce palatability.Now the researchers sought to identify a receptor that's required for sensing grittiness. They figured that it would be a mechanically-activated channel triggered when particles lightly bent a fly's taste hairs. However, the inactivation of known receptors had no impact on preference for food based on smoothness and grittiness.The authors then considered the protein TMEM63. "Fly TMEM63 is part of a class of mechano-sensors conserved from plants to humans," Montell said, "but its roles in animals were unknown."With only the suspicion that it might relay information about grittiness, Li and Montell inactivated the gene that codes for TMEM63 and compared the behavior of the mutant flies with wild-type animals.After withholding food from the animals for a couple hours, the researchers measured their interest in various sugar solutions mixed with particles of different sizes. They used the amount that the fly extended its proboscis to measure the animal's interest in the food it was presented. Li and Montell discovered that without TMEM63, the flies couldn't distinguish between a solution of pure sugar water and one containing small silica spheres around 9 micrometers in diameter, which is the flies' preferred level of grittiness.When they added chemicals to make the sugar solution less pleasant -- a mild acid, caffeine or moderate amounts of salt -- the microspheres reversed the flies' aversion. But not in flies lacking TMEM63. Upon restoring the gene that codes for this channel in the mutant flies' labella, the animals regained their ability to detect grittiness."It wasn't known before this study that flies could even discriminate foods on the basis of grittiness," Montell noted. "Now that we found that the mechanosensitive channel is TMEM63, we have uncovered one role for this protein in an animal."The TMEM63 channel functions in a single multi-dendritic neuron (md-L) in each of two labella at the end of the fly's proboscis. The neuron senses movements of most of the taste bristles on the labella. When the bristles move slightly upon interacting with food particle, it activates the TMEM63 channel, which stimulates the neuron that relays the sensation to the brain. Because one neuron connects to many bristles, it likely can't convey positional data of individual particles, only a gestalt sense of grittiness.By applying light force to these bristles -- mimicking the action of small particles in a gritty solution -- Montell and Li could activate the md-L neuron. However, the same procedure showed no effect in flies with TMEM63 knocked out. Interestingly, both groups of animals could detect larger forces on their bristles, such as might be caused by hard or viscous foods.Montell's team had previously shown that another channel called TMC, which is also expressed in md-L neurons, is important for detecting these larger forces. Both TMEM63 and TMC relay textural information about food, and even activate the same neuron. However, Li and Montell's results revealed that the two channels have distinct roles.Texture can provide a lot of information about food. It can indicate freshness or spoilage. For instance, fruit often become mealy when they start to spoil. "Animals use all the sensory information that they can to evaluate the palatability of food," Montell said. "This includes not only its chemical makeup, but color, smell, temperature and a variety of textural features."The 9 micrometer particle size that flies most enjoy corresponds in size to some of their preferred foods, like budding yeast and the particles in their favorite fruit," he explained.Montell suggested TMEM63 almost certainly has many other roles in animals. "This protein is conserved in humans," Montell said. "We don't know if it has a role in texture sensation in humans, but some kind of mechanically-sensitive channel probably does."
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Animals
| 2,021 |
March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302130633.htm
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Wolf social group dynamics matter for infectious disease spread, models suggest
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By modeling wolves in Yellowstone National Park, researchers have discovered that how a population is organized into social groups affects the spread of infectious diseases within the population. The findings may be applicable to any social species and could be useful in the protection of endangered species that suffer from disease invasion.
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Like other social carnivores, wolves tend to form territorial social groups that are often aggressive toward each other and may lead to fatalities. During these encounters, infectious diseases -- like mange and canine distemper -- can spread between groups, which can further reduce the number of individuals in a group."Previous social group-disease models have assumed that groups do not change throughout the course of an infection, when in reality, this is unlikely to be true," said Ellen Brandell, a recently graduated doctoral student in biology, Penn State. "Individuals within groups may die, become infected and recover at different rates, and the group may split into multiple groups or multiple groups could combine into one. Our models account for these processes and provide a foundation for exploring relationships for many social species that have varying levels of social complexity."The researchers used demographic data from two decades of Yellowstone wolf research to create models for examining the effects of sarcoptic mange and canine distemper virus on wolves that accounts for both within-group and between-group processes. The models assume that disease processes, such as transmission rates, vary among groups and within groups.The models also allow for the incorporation of Allee effects, a phenomenon in which a group has a greater survival rate when there are more individuals in the group."Allee effects are especially important in social species that require assistance from others beyond reproduction to survive; for example, in animals that defend themselves from predators and hunt for prey as a group," said Peter Hudson, Willaman Professor of Biology, Penn State. "When pathogens kill individuals, this can cause the growth rate of small groups to slow, or even collapse, which, in turn can cause the greater population to decline in size."The team's model results, which appeared March 1 in the journal "This occurs because the rate of aggression between groups is reduced when the presence of the pathogen decreases the number of groups, which then allows healthy surviving groups to increase in size as they suffer lower rates of aggression," said Hudson.However, the team found that the total population size is reduced as a result of the introduction of pathogens."In other words," added Brandell, "when a pathogen is in a population, we might see fewer, larger groups, but the overall population size is still reduced."Importantly, the models demonstrated that low pathogen prevalence at the population level can mask high levels of prevalence within infected groups."This finding emphasizes the need for representative sampling in socially structured populations as pathogen outbreaks in unsampled groups can be missed," said Brandell. "Wildlife researchers and managers should sample from many groups in a population in order to accurately depict disease prevalence. For social carnivores, this means sampling across a larger area and monitoring many groups in a population."Hudson emphasized the importance of recognizing that population-level prevalence tends to be lower than the number of groups infected and the level of infection experienced by individuals in infected groups."This issue should be a central consideration when wildlife disease biologists are analyzing and interpreting prevalence and seroprevalence data," he said. "It may be especially helpful in the protection of endangered species, such as African wild dogs."Other authors on the paper include Andrew Dobson, professor of ecology and evolutionary biology, Princeton University; Paul Cross, disease ecologist, U.S. Geological Survey; and Douglas Smith, senior wildlife biology, Yellowstone National Park.The U.S. Geological Survey and the National Science Foundation supported this research.
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Animals
| 2,021 |
March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302104752.htm
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Mouse sperm generated in rats
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Making gametes such as sperm and eggs from pluripotent stem cells, primitive cells that can make all the tissues, greatly contributes to efficient reproduction of livestock animals and future assisted reproductive medicine. Researchers pave the way to achieve this goal using a body of xenogenic animals.
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The researchers previously developed a method to grow stem cells into an entire organ in the body, so-called blastocyst complementation. The blastocyst is a structure of early embryos. If stem cells are transplanted into the blastocyst obtained from animals that cannot make a certain organ, the stem cells compensate the missing organ in the developing body, and make the entire organ. "We expected this method is also applicable to the efficient production of gametes," explains an author who led the study, Dr. Toshihiro Kobayashi.A year ago, the researchers created a genetically modified rat that completely lacks sperm and eggs. They hypothesized that the rat can be used as an excellent host to grow exogenous stem cells into gametes.The researchers firstly transplanted allogenic rat stem cells into blastocyst obtained from rats that are unable to make gametes, and confirmed all the gametes were derived from the stem cells. The generated gametes deliver the genetic information from the stem cells to the next generation, which enables efficient production of genetically modified rats.Then, researchers tested whether xenogenic mouse stem cells can make mouse gametes in the body of rats. Remarkably, mouse germ cells including sperm and spermatids were observed in the testis of the rats, and the spermatids could fertilize with mouse eggs to produce healthy pups."Making gametes from stem cells even in the xenogenic environment is quite important for the application of this strategy," says another author led the study, Dr. Masumi Hirabayashi. "In the future, we may be able to use the method to preserve endangered species, since their stem cells are available due to iPS cell technology."
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Animals
| 2,021 |
March 2, 2021
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https://www.sciencedaily.com/releases/2021/03/210302075415.htm
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Coffee for the birds: Connecting bird-watchers with shade-grown coffee
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Since 1970, bird populations in North America have declined by approximately 2.9 billion birds, a loss of more than one in four birds. Factors in this decline include habitat loss and ecosystem degradation from human actions on the landscape.
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At the same time, enthusiasm for bird-watching has grown, with more than 45 million recreational participants in the United States alone. Now, researchers are looking into how to mobilize these bird enthusiasts to help limit bird population declines.Enter bird-friendly coffee.Bird-friendly coffee is certified organic, but its impact on the environment goes further than that: it is cultivated specifically to maintain bird habitats instead of clearing vegetation that birds and other animals rely on.Researchers from Virginia Tech's College of Natural Resources and Environment, Cornell University, and Columbia University explored whether bird-friendly coffee is on the radar of bird-watchers: are they drinking it and, if not, why not? The study results published in the journal "We know bird-watchers benefit from having healthy, diverse populations of birds, and they tend to be conservation-minded folks," explained Assistant Professor Ashley Dayer of Virginia Tech's Department of Fish and Wildlife Conservation. "My colleagues and I wanted to dig into this key audience to determine their interest in bird-friendly coffee."Bird-friendly coffee is shade-grown, meaning that it is grown and harvested under the canopy of mature trees, a process that parallels how coffee was historically grown. But with most farms in Central and South America and the Caribbean converting to full-sun operations, crucial bird habitats for migrating and resident bird species are being lost."Over recent decades, most of the shade coffee in Latin America has been converted to intensively managed row monocultures devoid of trees or other vegetation," explained Amanda Rodewald, the Garvin Professor and senior director of the Center for Avian Population Studies at the Cornell Lab of Ornithology. "As a result, many birds cannot find suitable habitats and are left with poor prospects of surviving migration and successfully breeding."Purchasing shade-grown coffee is one of seven simple actions that people can take as a step toward returning bird populations to their previous numbers. "But even simple actions are sometimes not taken by people who you would expect to be on board. Human behavior is complex -- driven by knowledge, attitudes, skills, and many other factors," explained Dayer, an affiliate of the Global Change Center housed in Virginia Tech's Fralin Life Sciences Institute.The research team surveyed more than 900 coffee-drinking bird-watchers to understand bird-friendly coffee behavior among bird-watchers."One of the most significant constraints to purchasing bird-friendly coffee among those surveyed was a lack of awareness," said Alicia Williams, lead author and former research assistant at the Cornell Lab of Ornithology and Virginia Tech. "This includes limits on understanding what certifications exist, where to buy bird-friendly coffee, and how coffee production impacts bird habitat.""I was surprised to see that only 9 percent of those surveyed purchased bird-friendly coffee and less than 40 percent were familiar with it," Williams added. "It was also interesting, though not surprising, that a large number of our respondents reported that the flavor or aroma of coffee was an important consideration in their coffee purchases, which could be a useful attribute of bird-friendly coffee to stress going forward."The next step to increasing awareness about shade-grown coffee and its potential impact on bird populations may include increased advertising for bird-friendly coffee, more availability of bird-friendly coffee, and collaborations between public-facing conservation organizations and coffee distributors.
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Animals
| 2,021 |
February 26, 2021
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https://www.sciencedaily.com/releases/2021/02/210226121306.htm
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Pioneering prehistoric landscape reconstruction reveals early dinosaurs lived on tropical islands
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A new study using leading edge technology has shed surprising light on the ancient habitat where some of the first dinosaurs roamed in the UK around 200 million years ago.
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The research, led by the University of Bristol, examined hundreds of pieces of old and new data including historic literature vividly describing the landscape as a "landscape of limestone islands like the Florida Everglades" swept by storms powerful enough to "scatter pebbles, roll fragments of marl, break bones and teeth."The evidence was carefully compiled and digitised so it could be used to generate for the first time a 3D map showing the evolution of a Caribbean-style environment, which played host to small dinosaurs, lizard-like animals, and some of the first mammals."No one has ever gathered all this data before. It was often thought that these small dinosaurs and lizard-like animals lived in a desert landscape, but this provides the first standardised evidence supporting the theory that they lived alongside each other on flooded tropical islands," said Jack Lovegrove, lead author of the study published today in The study amassed all the data about the geological succession as measured all round Bristol through the last 200 years, from quarries, road sections, cliffs, and boreholes, and generated a 3D topographic model of the area to show the landscape before the Rhaetian flood, and through the next 5 million years as sea levels rose.At the end of the Triassic period the UK was close to the Equator and enjoyed a warm Mediterranean climate. Sea levels were high, as a great sea, the Rhaetian Ocean, flooded most of the land. The Atlantic Ocean began to open up between Europe and North America causing the land level to fall. In the Bristol Channel area, sea levels were 100 metres higher than today.High areas, such as the Mendip Hills, a ridge across the Clifton Downs in Bristol, and the hills of South Wales poked through the water, forming an archipelago of 20 to 30 islands. The islands were made from limestone which became fissured and cracked with rainfall, forming cave systems."The process was more complicated than simply drawing the ancient coastlines around the present-day 100-metre contour line because as sea levels rose, there was all kinds of small-scale faulting. The coastlines dropped in many places as sea levels rose," said Jack, who is studying Palaeontology and Evolution.The findings have provided greater insight into the type of surroundings inhabited by the Thecodontosaurus, a small dinosaur the size of a medium-sized dog with a long tail also known as the Bristol dinosaur.Co-author Professor Michael Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said: "I was keen we did this work to try to resolve just what the ancient landscape looked like in the Late Triassic. The Thecodontosaurus lived on several of these islands including the one that cut across the Clifton Downs, and we wanted to understand the world it occupied and why the dinosaurs on different islands show some differences. Perhaps they couldn't swim too well.""We also wanted to see whether these early island-dwellers showed any of the effects of island life," said co-author Dr David Whiteside, Research Associate at the University of Bristol."On islands today, middle-sized animals are often dwarfed because there are fewer resources, and we found that in the case of the Bristol archipelago. Also, we found evidence that the small islands were occupied by small numbers of species, whereas larger islands, such as the Mendip Island, could support many more."The study, carried out with the British Geological Survey, demonstrates the level of detail that can be drawn from geological information using modern analytical tools. The new map even shows how the Mendip Island was flooded step-by-step, with sea level rising a few metres every million years, until it became nearly completely flooded 100 million years later, in the Cretaceous.Co-author Dr Andy Newell, of the British Geological Survey, said: "It was great working on this project because 3D models of the Earth's crust can help us understand so much about the history of the landscape, and also where to find water resources. In the UK we have this rich resource of historical data from mining and other development, and we now have the computational tools to make complex, but accurate, models."
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Animals
| 2,021 |
February 26, 2021
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https://www.sciencedaily.com/releases/2021/02/210226103805.htm
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Retroviruses are re-writing the koala genome and causing cancer
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The koala retrovirus (KoRV) is a virus which, like other retroviruses such as HIV, inserts itself into the DNA of an infected cell. At some point in the past 50,000 years, KoRV has infected the egg or sperm cells of koalas, leading to offspring that carry the retrovirus in every cell in their body. The entire koala population of Queensland and New South Wales in Australia now carry copies of KoRV in their genome. All animals, including humans, have gone through similar "germ line" infections by retroviruses at some point in their evolutionary history and contain many ancient retroviruses in their genomes. These retroviruses have, over millions of years, mutated into degraded, inactive forms that are no longer harmful to the host. Since in most animal species this process occurred millions of years ago, the immediate health effects on the host at that time are unknown but it has been suspected for some time that the invasion of a genome by a retrovirus may have considerable detrimental health effects. The koala is at a very early stage of this process when the retrovirus is still active and these health effects can be studied.
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Since retroviruses can cause cancer, it was thought that there is a link between KoRV and the high frequency of lymphoma, leukemia and other cancers in koalas from northern Australia. To investigate this link, scientists at the Leibniz-IZW sequenced DNA from wild koalas suffering from cancer. This allowed them to accurately detect the number of copies of KoRV in the koala genomes and identify the precise locations where the retrovirus had inserted its DNA. By comparing this information between healthy and tumour tissues in single koalas, and by comparing insertion sites between koala individuals, they found multiple links between KoRV and genes known to be involved in the kind of cancers to which koalas are prone."Each koala carries around 80 -- 100 inherited copies of KoRV in its genome. The genomic locations of most of these are not shared between koalas, indicating a rapid expansion and accumulation of KoRV copies in the population. Each time a retrovirus copies and re-inserts itself into the genome, it causes a mutation, potentially disrupting gene expression, which could be detrimental to the host," says Prof Alex Greenwood, Head of Department of Wildlife Diseases at the Leibniz-IZW. This means that by frequently copying itself to new locations in the genome, KoRV is currently conferring a high mutational load on the koala population. Tumour tissues contain many new copies of KoRV, indicating that KoRV is more active in tumour cells. These copies generally were located close to genes associated with cancer. New KoRV insertions in tumour tissues affected the expression of genes in their vicinity. Such changes in gene expression associated with cancer can cause increased cell growth and proliferation, which leads to tumours. Although other factors may also contribute to cancer in koalas, the mutational burden from KoRV likely increases the frequency of cells becoming cancerous and may shorten the time for cancer to develop.In one koala, a copy of KoRV was found that had incorporated an entire cancer-related gene from the koala genome into its DNA sequence. This greatly increased expression of this gene and most likely caused cancer in this particular koala. If this mutated virus is transmissible, it would be of grave concern for koala conservation efforts. Comparing the genomic location of KoRVs between koalas also suggests that KoRV may predispose related koalas to particular tumours, with koalas sharing KoRV insertions in specific cancer-related genes suffering from similar types of cancer which they can pass on to their offspring. Across all koalas studied, there were "hot spots" in the genome where KoRV frequently inserts itself. These hot spots were also located in proximity to genes associated with cancer. "In summary then, we find multiple links at the genomic level between cancer-related genes and KoRV, revealing ways in which KoRV underlies the high frequency of cancer in koalas," explains Gayle McEwen, scientist at the Leibniz-IZW.The results highlight the detrimental health consequences that wildlife species can suffer following germline infection by retroviruses. Germline invasions have been repeatedly experienced during vertebrate evolution and have shaped vertebrate genomes, including the lineage leading to modern humans. These were most likely associated with severe detrimental health effects, which must be endured and overcome to ensure species survival. The scientists at the Leibniz-IZW have previously shown that old retroviruses present in the koala genome aid the rapid degradation of KoRV. The koala finds itself in a race to survive the effects of KoRV long enough for the virus to be degraded. Considering the many threats to koalas, it is a race they need to win.
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Animals
| 2,021 |
February 26, 2021
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https://www.sciencedaily.com/releases/2021/02/210226091437.htm
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African leopard: A cat of all trades
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Large carnivores are generally sensitive to ecosystem changes because their specialized diet and position at the top of the trophic pyramid is associated with small population sizes. This in turn leads to lower genetic diversity in top predators compared to animals lower down the food chain. Genetic diversity is very important for a species' ability to survive and adapt to future changes.
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In this study, the researchers sequenced the complete genome of 53 African leopards and compared them to the Amur leopards and other big cat species. To their surprise, the researchers found that the genetic diversity of African leopards is extremely high: Almost four times higher than the Amur leopard's, twice as high as the lion's and almost five times higher than the cheetah's.Patrícia Pečnerová, postdoc at the Department of Biology and one of the shared first authors, explains: "The exceptional genetic diversity is likely a result of the leopard's ability to avoid population crashes and reductions. We found that during hundreds of thousands of years, African leopard populations remained large. We think that this reflects the versatility of the species, feeding on a wider variety of prey than any of the other large predators."The high genetic diversity of the African leopards is not the only surprise hidden in the leopard genomes. They also show fewer genetic barriers within the continent of Africa than other mammal species.Kristian Hanghøj, one of the corresponding authors of the study explains: "We believe that during evolutionary history the leopard roamed the African continent more freely than almost any other mammal species, exchanging genetic material throughout. It has a unique ability to succeed in almost any habitat and climate and neither rain forests, nor deserts seem to have blocked the movements of leopards over the millennia."The surprising findings demonstrate how the ecology of a species -- such as how 'picky' it is about habitat and prey, can influence its genomic variation. The exceptionally high genetic diversity could give the African leopard an advantage in coping with environmental challenges, including climate change and habitat destruction.However, habitat fragmentation is a severe threat to all large animals, even those as adept at coping with human presence as the leopard. The human-made changes to natural habitats are occurring at a pace that is likely too fast for almost any wild animal species to adapt to, and previous studies have shown that African leopards have lost 48-67% of their natural habitat over the last 300 years."To place our results into a greater context, we emphasize that the African leopard is also facing severe threats to its survival, despite being sort of an evolutionary success," finishes Patrícia Pečnerová..
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Animals
| 2,021 |
February 25, 2021
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https://www.sciencedaily.com/releases/2021/02/210225143920.htm
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Did teenage 'tyrants' outcompete other dinosaurs?
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Paleo-ecologists from The University of New Mexico and at the University of Nebraska-Lincoln have demonstrated that the offspring of enormous carnivorous dinosaurs, such as Tyrannosaurus rex may have fundamentally re-shaped their communities by out-competing smaller rival species.
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The study, released this week in the journal "Dinosaur communities were like shopping malls on a Saturday afternoon -- jam-packed with teenagers," explained Kat Schroeder, a graduate student in the UNM Department of Biology who led the study. "They made up a significant portion of the individuals in a species and would have had a very real impact on the resources available in communities."Because they were born from eggs, dinosaurs like T. rex necessarily were born small -- about the size of a house cat. This meant as they grew to the size of a city bus, these "megatheropods," weighing between one and eight tons, would have changed their hunting patterns and prey items. It's long been suspected by paleontologists that giant carnivorous dinosaurs would change behavior as they grew. But how that might have affected the world around them remained largely unknown."We wanted to test the idea that dinosaurs might be taking on the role of multiple species as they grew, limiting the number of actual species that could co-exist in a community," said Schroeder.The number of different types of dinosaurs known from around the globe is low, particularly among small species."Dinosaurs had surprisingly low diversity. Even accounting for fossilization biases, there just really weren't that many dinosaur species," said Felisa Smith, professor of Biology at UNM and Schroeder's graduate advisor.To approach the question of decreased dinosaur diversity, Schroeder and her coauthors collected data from well-known fossil localities from around the globe, including over 550 dinosaur species. Organizing dinosaurs by mass and diet, they examined the number of small, medium and large dinosaurs in each community.They found a strikingly clear pattern:"There is a gap -- very few carnivorous dinosaurs between 100-1000kg [200 pounds to one ton] exist in communities that have megatheropods," Schroeder said. "And the juveniles of those megatheropods fit right into that space."Schroeder also notes that looking at dinosaur diversity through time was key. Jurassic communities (200-145 million years ago) had smaller gaps and Cretaceous communities (145-65 million years ago) had large ones."Jurassic megatheropods don't change as much -- the teenagers are more like the adults, which leaves more room in the community for multiple families of megatheropods as well as some smaller carnivores," Schroeder explained. "The Cretaceous, on the other hand, is completely dominated by Tyrannosaurs and Abelisaurs, which change a lot as they grow."To tell whether the gap was really caused by juvenile megatheropods, Schroeder and her colleagues rebuilt communities with the teens taken into account. By combining growth rates from lines found in cross-sections of bones, and the number of infant dinosaurs surviving each year based on fossil mass-death assemblages, the team calculated what proportion of a megatheropod species would have been juveniles.Schroeder explained that this research is important because it (at least partially) elucidates why dinosaur diversity was lower than expected based on other fossil groups. It also explains why there are many more very large species of dinosaurs than small, which is the opposite of what would be expected. But most importantly, she added, it demonstrates the results of growth from very small infants to very large adults on an ecosystem."Dinosaurs have been a life-long passion. I was, and still very much am a 'dinosaur kid.' My interest in dinosaur diversity came about when I realized that no one was really looking at dinosaurs the way we look at modern mammals and birds," Schroeder said. "There's a ton to be gained from applying the methods of modern and paleo-ecology to dinosaurs. Fortunately, we're now in an age of dinosaur research where a lot of information is available digitally, so the big data-intensive questions of ecology are now becoming more plausible for dinosaur paleontology."
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February 25, 2021
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https://www.sciencedaily.com/releases/2021/02/210225113235.htm
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New North Atlantic right whale health assessment review
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Woods Hole Oceanographic Institution (WHOI) along with National Oceanic and Atmospheric Administration (NOAA) Fisheries have released the first broad scale synthesis of available information derived from right whale health assessment techniques. The manuscript published today in the science journal
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The manuscript is the result of a NOAA Fisheries workshop held in June 2019, in response to the ongoing North Atlantic right whale Unusual Mortality Event (UME) and the critically endangered status of the species. There are an estimated 366 left on the planet. Climate change, vessel strikes, entanglements and noise pollution can result in poor health and reproductive failure and are major threats to individuals and the species.According to lead author Michael Moore, a whale trauma specialist at WHOI, "North Atlantic right whales face a serious risk of extinction, but there is hope if we can work together on solutions. Trauma reduction measures and applying new tools to assess their health are critically important to enhance the welfare of individual whales. If we can reduce the number of deaths, and successfully improve their health to increase reproduction, the current decline in population can be reversed.""Conserving and recovering the critically endangered North Atlantic Right Whale is a research priority," said co-author Teri Rowles, NOAA Fisheries Senior Advisor for Marine Mammal Health Science. "In addition to the threats posed by humans, changing ocean conditions have profound impacts on where whales travel and how they behave. For these reasons, NOAA Fisheries was pleased to have hosted and sponsored this important workshop among partners to discuss how science can aid management."Bringing together the data and results from existing monitoring tools like aerial and vessel photography, animal sampling and prey dynamics, in the context of vessel and fishing gear trauma offers researchers a better understanding of the challenges, and possible solutions. These include a greater emphasis in slowing vessels and changing their tracks where risk of collision exists; reducing entanglement by closing more high-risk areas to fixed fishing gear that retains rope in the water column; and reducing fishing gear density and strength in other areas.North Atlantic right whales feed in the waters off New England and Eastern Canada and migrate to the waters off the Southeastern United States to give birth in the winter. NOAA Fisheries has designated two critical habitat areas for the North Atlantic population of right whales, including off the coast of New England and off the southeast U.S coast from North Carolina to below Central coastal Florida.
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Animals
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February 25, 2021
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https://www.sciencedaily.com/releases/2021/02/210225082552.htm
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Chimpanzees and humans share overlapping territories
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Chimpanzees and humans "overlap" in their use of forests and even villages, new research shows.
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Scientists used camera traps to track the movements of western chimpanzees -- a critically endangered species -- in Guinea-Bissau.Chimpanzees used areas away from villages and agriculture more intensively, but entered land used by humans to get fruit -- especially when wild fruits were scarce.Researchers from the University of Exeter and Oxford Brookes University say the approach used in this study could help to inform a "coexistence strategy" for chimpanzees and humans."Understanding how wildlife balance the risks and rewards of entering environments used by humans is crucial to developing strategies to reduce risks of negative interactions, including disease transmission and aggression by animals or humans," said lead author Dr Elena Bersacola, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall."Using 12 months of data from 21 camera traps, our study produced hotspot maps that show how humans and chimpanzees overlap in their use of forests, villages and cultivated areas."Chimpanzee use of space was linked to the availability of naturalised oil-palm fruit, and the study also shows that chimpanzees access high-risk orange, lime and papaya fruits in response to nutritional necessity rather than preference alone.The study used a "landscape of fear" framework, based on the idea that animals learn about risks and the resulting fear shapes their decisions over where and when to feed, travel and rest.Researchers are increasingly incorporating humans as agents for shaping the wildlife's landscapes of fear.The team in this study were cautious not to let the chimpanzees become "habituated" (used to humans, and therefore not fearful)."Elena got around this problem by setting up a patchwork of camera traps throughout one chimpanzee community's home range and monitoring their use of space," said Dr Kimberley Hockings, of the University of Exeter."The methods and analyses Elena used are new and exciting and have helped us understand human-chimpanzee coexistence across the landscape."This is important because western chimpanzees are critically endangered and these shared landscapes are crucial for their persistence."These methods can also be applied to other threatened wildlife that are being pushed into ever-increasing human-impacted landscapes across the globe."Professor Catherine Hill, of Oxford Brookes University, said: "Our modelling approach generates fine-resolution space-time output maps, which can be scaled-up to identify human-wildlife interaction hotspots."Our method provides the necessary tools to understand and more effectively manage human-wildlife coexistence at different spatial scales, including the management of resources important to both."
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February 25, 2021
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https://www.sciencedaily.com/releases/2021/02/210225082449.htm
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Human-caused North Atlantic right whale deaths are being undercounted
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A study co-authored by scientists at the New England Aquarium has found that known deaths of critically endangered North Atlantic right whales represent a fraction of the true death toll. This comes as the death of a calf and recent sightings of entangled right whales off the southeastern United States raise alarm.
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The study, published this month in "Our work has shown that 83% of identified right whales have been entangled one or more times in fishing gear, and an increasing number of these events result in severe injuries or complex entanglements that the whales initially survive. But we know their health becomes compromised and they eventually succumb and sink upon death," said Amy Knowlton, senior scientist with the Aquarium's Anderson Cabot Center for Ocean Life.The study -- led by Richard Pace and Rob Williams and co-authored by Knowlton, New England Aquarium Associate Scientist Heather Pettis, and Aquarium Emeritus Scientist Scott Kraus -- determined that several factors interact to cause undercounting of human-caused mortalities of marine mammals. First, in order for a human-caused mortality to be determined, a whale carcass must float or strand, be detected before decomposition or scavenging occurs, be evaluated to determine cause of death, and then have that result reported. In the absence of any of these steps, information about the cause of mortality can easily be lost.Additionally, a number of right whales have been observed entangled or injured from vessel strikes and never seen again. This suggests they died and their carcasses were not discovered."We have long known that the number of detected right whale carcasses does not align with the number of whales that disappear from the sightings records," Pettis said. "Since 2013 alone, we have documented 40 individual right whales seen with severe injuries resulting from vessel strikes and entanglements that disappeared following their injury. This study allowed us to quantify just how underrepresented true right whale mortalities are when we rely on observed carcasses alone."The estimated population number for North Atlantic right whales stands at just over 350 whales. Right whales are one of the most endangered large whale species in the world, facing serious ongoing threats from vessels and fishing gear. Just in the past month, a right whale calf died in an apparent vessel strike and two right whales have been spotted entangled in fishing gear. A sport fishing boat hit and killed the calf in the calving grounds off the Florida coast on February 12. The calf was the first born to Infinity (Catalog #3230), who also suffered injuries consistent with a vessel strike. Catalog #1803, a 33-year-old male, was seen badly entangled off the coast of Georgia and Florida in mid-January, and on February 18, Cottontail (Catalog #3920) was sighted entangled and emaciated off the Florida coast. Cottontail, an 11-year-old male, was first seen entangled in southern New England last fall. In both cases, disentanglement efforts were not successful and these whales will likely die."These serious entanglements are preventable with regulatory changes and a commitment from the fishing industry and the U.S. and Canadian governments to do more to address this threat," said Knowlton.For 40 years, the Aquarium's Right Whale Research Program has extensively studied this critically endangered species. Scientists focus on solutions-based work, collaborating with fishermen on new techniques to reduce deadly entanglements in fishing gear, facilitating communication across the maritime industry to reduce vessel strikes, and working with lawmakers locally, nationally, and internationally to develop science-based protections for the whales.
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Animals
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February 24, 2021
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https://www.sciencedaily.com/releases/2021/02/210224143517.htm
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Scientists map the brain of a nematode worm
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Researchers have mapped the physical organization of the brain of a microscopic soil-living nematode worm called
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In a surprise twist, they found a large degree of variation in the structure of some neural circuits or pathways in individual worms which complemented a core set of neural circuits common to different animals.The scientists say the worms' brains might have a lot more in common with larger animals than previously thought.Created by neuroscientists at the University of Leeds in collaboration with researchers in New York's Albert Einstein College of Medicine, the brain map reveals that different spatial regions support different specialised circuits for routing information in the brain, where information is integrated before being acted upon.The study is published today (24 Feb) in the scientific journal An adult worm has exactly 302 cells in its nervous system -- by comparison, the human brain has around 100 billion cells. But almost two thirds of the worm's nerve cells form a ring in the head region, where they make thousands of connections with each other.This 'brain' is the control centre of the animal, where much of the sensing and decision-making takes place.Even though the brain is very compact, the animal displays a range of complex behaviours, and neuroscientists have been interested in understanding its brain for decades. Previous studies have created 'wiring diagrams' for the connections between nerve cells.This latest study, though, is the first to provide the complete spatial coordinates to those circuit diagrams.Professor Netta Cohen, Computational Neuroscientist at the University of Leeds, who supervised the research, said: "The brain needs to organise information flow to control the animal's behaviour. But how the structure and function of the brain are related is an open question. Providing the spatial representation of the circuitry has allowed us to uncover the modular structure of this animal's brain."The researchers used a legacy collection of electron microscope images of the brain of an adult and juvenile nematode worm. Those images revealed individual brain cells or neurons, allowing the researchers to map the organisation of the worms' neural circuits, from the level of individual cells through to the large scale architecture of the entire brain.The scientists identified known neural circuits and pathways within the brain such as a navigation neural circuit which an animal would use to follow smells and tastes to forage for food. Another circuit is thought to facilitate mechano-sensation, so it would feel its way as it wriggles through the soil -- or sense if it is surrounded by bacteria.Their theory is that information is processed in the worm's brain through a number of 'layers'. In fact, a similar layered architecture is found in the human brain. Information flow starts in sensory cells, which respond to the environment. For example, cells may sense bacteria but are they the right bacteria to feed on -- do they smell like the 'right' bacteria? The answer requires information to be integrated from multiple senses before being sent to the command area of the brain for action.Professor Cohen said: "The brain map reveals a very elegant structure to support information flow through a worm's brain and it is more sophisticated than the traditional view that simple animals follow a stimulus-response path."The map suggests a convergence of different neural circuits -- and this allows the worm to integrate all of the different cues it is receiving through its sensory cells and to coordinate the response."During their study, the researchers were surprised to discover the extent of individual variation in the worms' brains.Using mathematical and computer models, the scientists were able to discern between those connections that are likely to form the 'core' circuit across a large population of animals, and those that appear to be variable between individuals.Dr. Christopher Brittin, a former PhD student at the University of Leeds and first author on the paper said: "This work raises interesting questions about how even seemingly simple nervous systems are able to accommodate both core and individualized brain circuitry."The scientists found that only around half the wiring in the worms' brains is similar -- the other half showed variation.Professor Cohen added: "This finding was really exciting for us. First, this suggests that worm brains have a lot more in common with the brains of higher animals than we knew or expected, and the lessons learned about worms can help us learn about brains more generally."The variable connectivity may support individuality, redundancy and adaptability of brains as the animals face challenging, dangerous and ever-changing environments.
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February 24, 2021
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https://www.sciencedaily.com/releases/2021/02/210224120338.htm
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Using a multipronged approach to investigate the diet of ancient dogs
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Coprolites, or fossilized dog feces, are often used to understand the dietary preferences of ancient civilizations. However, the samples are often contaminated, making the analysis difficult. A new study, published in
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"We have been interested in analyzing coprolites for many years. We have attempted to extract DNA and look at the microbiome before, but the tools were not as robust," said Ripan Malhi (GNDP/GSP/IGOH), a professor of anthropology. "As far as I know, this is the first time anyone has used multiple approaches to provide a snapshot of the daily diet, health, and the long-term trends in ancient dogs of the Americas, all in one study."The samples were recovered from Cahokia, near modern St. Louis, Missouri. At its peak, Cahokia was a large urban center with a population greater than London or Paris. Several other investigations have shown that there is an overlap between the diet of dogs and humans, either because the dogs were fed the same food or because they ate human food scraps. Therefore, investigating coprolites also provides an insight into human health and diet."Initially, the residents were growing crops such as squash and sunflowers. As the city got bigger, it is believed that the diet shifted to maize. Our analysis suggests the same since we saw that some of the dogs were also eating maize," said Kelsey Witt, a postdoctoral researcher at Brown University and former PhD student in the Malhi lab.The maize samples were examined using stable isotope analysis, which is used to measure different forms of carbon in a sample. Depending on the carbon concentrations, one can identify what kind of plant was consumed. The researchers also investigated the animal and plant remains in the coprolites to show that walnuts, grapes, a variety of fish, and duck were a part of the dogs' diet.The researchers also used DNA sequencing to determine the microbiome -- the community of microbes -- of the coprolites. "The technique we used came out in 2020. It helped us verify whether the samples were from dogs or humans, as well as confirm general aspects of diet which can only be done by comparing the microbiomes," said Karthik Yarlagadda, a PhD student in the Malhi lab.Although the techniques are novel and more sensitive, coprolites are still challenging to study for a number of reasons. The DNA has already passed through the digestive process in the dogs and has therefore been broken down. Furthermore, since the samples are ancient, the extracted DNA is degraded to a large extent due to weathering."One of the biggest challenges we faced was dealing with sample contamination," Yarlagadda said. "These samples were deposited a thousand years ago. After that, the environment changed, certain microbes died off, and new microbes took over. All these factors complicate the analysis."The researchers are working with the Indigenous communities to further understand what the diets looked like in their ancestors. "Since there are a lot of limitations to our research, talking to community members about what their ancestors ate and how they interacted with dogs helps us understand our results better," Witt said.
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Animals
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February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223192442.htm
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How did dogs get to the Americas? An ancient bone fragment holds clues
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The history of dogs has been intertwined, since ancient times, with that of the humans who domesticated them.
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But how far back does that history go in the Americas, and which route did dogs use to enter this part of the world?A new study led by the University at Buffalo provides insight into these questions. The research reports that a bone fragment found in Southeast Alaska belongs to a dog that lived in the region about 10,150 years ago. Scientists say the remains -- a piece of a femur -- represent the oldest confirmed remains of a domestic dog in the Americas.DNA from the bone fragment holds clues about early canine history in this part of the world.Researchers analyzed the dog's mitochondrial genome, and concluded that the animal belonged to a lineage of dogs whose evolutionary history diverged from that of Siberian dogs as early as 16,700 years ago. The timing of that split coincides with a period when humans may have been migrating into North America along a coastal route that included Southeast Alaska.The research will be published on Feb. 24 in the "We now have genetic evidence from an ancient dog found along the Alaskan coast. Because dogs are a proxy for human occupation, our data help provide not only a timing but also a location for the entry of dogs and people into the Americas. Our study supports the theory that this migration occurred just as coastal glaciers retreated during the last Ice Age," says Lindqvist, PhD, associate professor of biological sciences in the UB College of Arts and Sciences. "There have been multiple waves of dogs migrating into the Americas, but one question has been, when did the first dogs arrive? And did they follow an interior ice-free corridor between the massive ice sheets that covered the North American continent, or was their first migration along the coast?""The fossil record of ancient dogs in the Americas is incomplete, so any new remains that are found provide important clues," says Flavio Augusto da Silva Coelho, a UB PhD student in biological sciences, and one of the paper's first authors. "Before our study, the earliest ancient American dog bones that had their DNA sequenced were found in the U.S. Midwest."Lindqvist's team did not set out to study dogs. The scientists came across the femur fragment while sequencing DNA from a collection of hundreds of bones excavated years before in Southeast Alaska by researchers including Timothy Heaton, PhD, professor of earth sciences at the University of South Dakota."This all started out with our interest in how Ice Age climatic changes impacted animals' survival and movements in this region," Lindqvist says. "Southeast Alaska might have served as an ice-free stopping point of sorts, and now -- with our dog -- we think that early human migration through the region might be much more important than some previously suspected."The bone fragment, originally thought to come from a bear, was quite small, but when the DNA was studied, the team realized it was from a dog, Lindqvist says.After this surprise discovery, the scientists compared the bone's mitochondrial genome to those of other ancient and modern dogs. This analysis showed that the Southeast Alaskan dog shared a common ancestor about 16,000 years ago with American canines that lived before the arrival of European colonizers, Lindqvist says. (Mitochondrial DNA, inherited from the mother, represents a small fraction of an organism's complete DNA, so sequencing a complete nuclear genome could provide further details if that material can be extracted.)Of interest, carbon isotope analysis on the bone fragment indicates that the ancient Southeast Alaskan dog likely had a marine diet, which may have consisted of foods such as fish and scraps from seals and whales.The research adds depth to the layered history of how dogs came to populate the Americas. As Lindqvist notes, canines did not arrive all at once. For example, some Arctic dogs arrived later from East Asia with the Thule culture, while Siberian huskies were imported to Alaska during the Gold Rush. Other dogs were brought to the Americas by European colonizers.The new study sharpens the debate on dog and human migration into the Americas."Our early dog from Southeast Alaska supports the hypothesis that the first dog and human migration occurred through the Northwest Pacific coastal route instead of the central continental corridor, which is thought to have become viable only about 13,000 years ago," Coelho notes.The research was funded by the National Science Foundation. In addition to Lindqvist, Coelho and Heaton, authors of the new paper in
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Animals
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February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223110733.htm
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The way a fish swims reveals a lot about its personality, say scientists
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Personality has been described in all sorts of animal species, from ants to apes. Some individuals are shy and sedentary, while others are bold and active. Now a new study published in
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This new research suggests experts can reliably measure animal personality simply from the way individual animals move, a type of micropersonality trait, and that the method could be used to help scientists understand about personality differences in wild animals.A team of biologists and mathematicians from Swansea University and the University of Essex filmed the movements of 15 three-spined stickleback fish swimming in a tank which contained two, three, or five plastic plants in fixed positions.Using the high-resolution tracking data from video recordings, the team took measurements of how much and how often the fish turned, and how much they stopped and started moving.The data revealed that each fish's movements were very different, and that these differences were highly repeatable -- so much so that the researchers could identify a fish just from its movement data.Dr Ines Fürtbauer, a co-author of the study from Swansea University, said: "These micropersonalities in fish are like signatures -- different and unique to an individual. We found the fish's signatures were the same when we made simple changes to the fish tanks, such as adding additional plants. However, it is possible these signatures change gradually over an animal's lifetime, or abruptly if an animal encounters something new or unexpected in its environment. Tracking animals' motion over longer periods and in the wild will give us this sort of insight and help us better understand not only personality but also how flexible an animal's behaviour is."The authors of the study say that further work with other species and contexts is needed to see how general the phenomenon is, and if the same patterns are seen with land animals or flying species.Dr Andrew King, lead author from Swansea University, said: "Our work suggests that simple movement parameters can be viewed as micropersonality traits that give rise to extensive consistent individual differences in behaviours. This is significant because it suggests we might be able to quantify personality differences in wild animals as long as we can get fine-scale information on how they are moving; and these types of data are becoming more common with advances in animal tracking technologies."
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Animals
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February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223110500.htm
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Whale sharks show remarkable capacity to recover from injuries, including partial fin re-growing
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A new study has for the first time explored the rate at which the world's largest fish, the endangered whale shark, can recover from its injuries. The findings reveal that lacerations and abrasions, increasingly caused through collisions with boats, can heal in a matter of weeks and researchers found evidence of partially removed dorsal fins re-growing.
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This work, published in the journal "These baseline findings provide us with a preliminary understanding of wound healing in this species" says lead author Freya Womersley, a PhD student with University of Southampton based at the Marine Biological Association, UK. "We wanted to determine if there was a way of quantifying what many researchers were anecdotally witnessing in the field, and so we came up with a technique of monitoring and analysing injuries over time."The unique spot markings of whale sharks allow researchers across the world to identify individuals and monitor regional populations, making use of websites such as WildBook where people can upload photos of their shark sightings. For this study, the research team examined photographs taken by citizen scientists, researchers and the whale shark tourism industry in two sites in the Indian Ocean where the sharks frequently gather, and used these markings to standardise between images. This method allowed the team to compare photographs taken without specialist equipment over time and increased the amount of data available to assess and monitor how individual wounds changed."By using our new method, we were able to determine that these sharks can heal from very serious injuries in timeframes of weeks and months" says Freya. "This means that we now have a better understanding of injury and healing dynamics, which can be very important for conservation management."The study also highlighted whale sharks' capability to re-grow a partially amputated first dorsal fin, which, to the authors' knowledge, is the first time a shark has ever been scientifically reported exhibiting this phenomenon. Of further interest, their unique spot markings were also observed forming over previously injured spots, which suggests that these beautiful markings are an important feature for this species and persist even after being damaged.These healing capabilities suggest that whale sharks may be resilient to impacts caused by humans, but the authors of this work note that there may be many other less recognisable impacts of injuries to these animals, such as reduced fitness, foraging capacity and altered behaviours; so injuries need to be prevented where possible. They also found variation within healing rates, with lacerations, typical of propeller injuries, taking longer to heal than other kinds of wounds, highlighting the need for further research to determine the influence of environmental and more nuanced individual factors on injury healing.Careful management of whale shark aggregation sites, which occur seasonally at a number of coastal regions around the world, is essential to ensure the sharks are protected while spending time in areas of high human activity. If sharks are encountered with injuries in these locations, research such as this can help local teams estimate how old the injury is and make assessments about where and how it might have been inflicted based on knowledge of whale shark movements and tendency to return to the same locations.Recent research published in Freya concludes, "Whale sharks have been experiencing population declines globally from a variety of threats as a result of human activity. Therefore, it is imperative that we minimise human impacts on whale sharks and protect the species where it is most vulnerable, especially where human-shark interactions are high."There is still a long way to go in understanding healing in whale sharks, and in shark species in general, but our team hope that baseline studies such as this one can provide crucial evidence for management decision makers that can be used to safeguard the future of whale sharks."
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Animals
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February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223110356.htm
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Drifter or homebody? Study first to show where whitespotted eagle rays roam
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Its muscular body shape and large pectoral fins are perfect for long-distance travel, yet movement patterns of the whitespotted eagle ray (Aetobatus narinari) remain a mystery. Researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute in collaboration with Mote Marine Laboratory & Aquarium, the University of Florida and the Florida Fish and Wildlife Conservation Commission, are the first to conduct a multiyear study examining large-scale movements of whitespotted eagle rays in United States waters.
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Between 2016 and 2018, scientists fitted 54 rays with acoustic transmitters and tracked them using collaborative acoustic telemetry networks. The rays were tagged along both the Gulf of Mexico and Atlantic coasts of Florida, which differ in environmental characteristics. Scientists compared rays' movement patterns between the Atlantic and Gulf coasts and gathered data on migratory routes, seasonality and habitat use. Their findings suggest that potential sub-population structuring may be occurring within Florida more than previously thought and have significant conservation and adaptive management implications for this protected species.Results of the study, published in the journal "Although tagged at similar latitudes, whitespotted eagle rays exhibited coastline-specific movements. The rays on the Gulf coast conduct repetitive annual migration patterns, heading south from Sarasota starting in fall and returning to the area in early spring," said Breanna DeGroot, M.S., first author and research coordinator, FAU Harbor Branch.DeGroot worked on the study with co-author Matt Ajemian, Ph.D., principal investigator, an assistant research professor at FAU Harbor Branch and head of the Fisheries Ecology and Conservation (FEC) Lab, who supervised the study."This behavior is likely driven by a combination of environmental factors, but most notably temperature. In addition, the expansive, shallow shelf on the Gulf coast may provide additional habitat, enabling rays to move over larger distances along nearshore migratory corridors and lessen their reliance on inshore estuaries," said Ajemian.On both coastlines, water temperatures during times when rays were present were significantly warmer (at least 27.8 degrees Celsius) compared to temperatures when rays were absent (below 24.9 degrees Celsius), suggesting it may be a major abiotic factor influencing migration patterns. Ontogenetic shifts in habitat use were evident along the Atlantic coast in the Indian River Lagoon, but not along the Gulf coast. Immature rays spent significantly more time (about 91.5 percent) inside the Indian River Lagoon compared to mature counterparts (about 60.2 percent)."Most of the rays we tagged on Florida's Atlantic coast resided in the same area where they were originally tagged, which increases their susceptibility to local stressors like persistent environmental impacts in the Indian River Lagoon," said DeGroot. "Moreover, immature rays spent a significantly larger proportion of time inside the confines of the lagoon. This is especially disconcerting because we found no evidence of neonate or young-of-the-year rays leaving the lagoon throughout the entire three-year study."The consistent presence of rays in the Indian River Lagoon throughout the study suggests that it serves as parturition grounds and nursery habitat for rays. As males and females were equally resident to the Sebastian portion of the Indian River Lagoon, this area is likely an important feeding ground, nursery habitat, mating location, pupping ground, or serves a combination of these roles."This information about year-round or seasonal residency and longer distance migrations would not be possible without the collaborative data sharing of the acoustic telemetry networks such as iTAG and the FACT Network," said Kim Bassos-Hull, M.Sc., co-author and senior biologist with Mote Marine Lab's Sharks & Rays Conservation Research Program.According to Ajemian, there is a need for a better understanding of how extreme weather events such as hurricanes and fluctuations in environmental factors such as red tide and harmful algal blooms may impact ecologically important large-bodied mesopredators like the whitespotted eagle ray, because the frequency of these events is predicted to increase yet the potential alterations on the ecosystem remain unknown."This is a critical issue that requires increased tracking infrastructure and new analytical approaches," said Susan Lowerre-Barbieri, Ph.D., co-author, University of Florida and Florida Fish and Wildlife Conservation Commission, who led an iTAG workshop on this topic.Study co-authors are Krystan A. Wilkinson, Ph.D., Mote Marine Lab's Sharks & Rays Conservation Research Program and the Chicago Zoological Society's Sarasota Dolphin Research Program; and Gregg R. Poulakis, Ph.D., Florida Fish and Wildlife Conservation Commission."I'm looking forward to adding more pieces to the eagle ray puzzle in the coming years as these animals get detected for years to come along both coasts of the state and beyond," said Poulakis.Rays were tagged using handling permits: Gulf coast, FWC SAL-16-1140-SRP; Atlantic coast, FWC SAL-16-1785-SRP.This work was funded by the Guy Harvey Ocean Foundation, Vero Beach Rotary Club, Indian River Graduate Research Fellowship (2017, 2018), "3-min Thesis Award," Specialty License Plate (Save Our Seas) fund administered by the Harbor Branch Oceanographic Institute Foundation, Mote Scientific Foundation, Georgia Aquarium, and the NOAA-NMFS Species Recovery Grants to States (Section 6 Program).
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Animals
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February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223100710.htm
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Saki monkeys get screen time for more control over their lives in captivity
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Technology helps humans maintain connections, get work done, and relax after a long day. How it can best improve the lives of animals, particularly those in captivity, however, has remained an open question.
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Scientists from Aalto University, in collaboration with Korkeasaari Zoo, have designed and built an on-demand video device for white-faced saki monkeys to activate as and when they like. While enrichment systems for zoo animals have been around for some time, very few offer animals the ability to choose when and how they use the device, even though choice and control are known to promote animal welfare.'We were very much interested in how we can give animals control over their environment and especially how they can control technology. Typically, when we use technology with animals, we use it on them, so we play them sounds or video, rather than giving them the option of controlling the technology themselves,' says Ilyena Hirskyj-Douglas, lead author and visiting researcher at Aalto University.The device, a tunnel built of plywood and acrylic and equipped with a monitor, camera and sensors to monitor the use of space, was placed in the saki habitat at Korkeasaari Zoo, located in the Finnish capital of Helsinki. It was up to the animals to decide whether they wanted to step inside the device -- the equivalent of pressing play -- to see the video of the week. During the study, the device played five different kinds of scenes: sealife like fish and jellyfish, wiggly worms, other zoo animals like zebras, makis and dear, abstract art, or lush forests.'We got interesting results. First of all, we learned that the monkeys do pay attention to the screen; they watch it and touch it. We also suspect they recognize objects on the screen. One of the videos we had featured meal worms -- an everyday meal for them. They actually tried to lick the screen and even went around the tunnel to see if the worms were behind it,' explains Vilma Kankaanpää, co-author of the paper and Master's student at Aalto University.Despite keen observation, it's difficult to say with certainty which video the monkeys liked the most. They spent most of their time watching slithering worms or underwater scenes but these were also the videos accessible at the middle of the study, when they were accustomed to using the device, but it was still fairly new.The researchers, however, found that, in comparison to the no-video control condition, the sakis scratched themselves significantly less often when presented with video content. For monkeys in captivity, scratching can be a sign of stress.While a causal link between specific activities and animals' stress levels cannot be made, one thing is sure: different types of stimuli gives them new things to do, which is important for their wellbeing.The researchers based the video device on their previous research published in autumn 2020, in which they used the same tunnel-shaped device to play the sakis different sounds and music. At the time, researchers found that monkeys listened more to the sounds of traffic than to the sounds of rain, music, or silence.Kirsi Pynnönen-Oudman, research coordinator at Korkeasaari Zoo, believes that both audio and video can be used to enrich the lives of primates and possibly some birds, such as parrots and crows, living at their facilities also in the future.'The equipment must, of course, withstand the handling of animals, and those which have, for example, sharp teeth must have their own equipment. The advantage is that the availability of video and audio content is almost unlimited, so the use of the device is not expensive,' Pynnönen-Oudman says.
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Animals
| 2,021 |
February 23, 2021
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https://www.sciencedaily.com/releases/2021/02/210223110715.htm
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DNA extracted from modern, ancient and fossil tropical shells
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In Wonderland, Alice drank a potion to shrink herself. In nature, some animal species shrink to escape the attention of human hunters, a process that takes from decades to millennia. To begin to understand the genetics of shrinking, scientists working at the Smithsonian Tropical Research Institute (STRI) in Panama successfully extracted DNA from marine shells. Their new technique will not only shed light on how animals from lizards to lemurs shrink, it will reveal many other stories hidden in shells.
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"Humans are unique as predators," said Alexis Sullivan, doctoral student at Penn State University who did the field research as a short-term fellow at STRI. "Most other animals go for smaller, younger, older or injured prey that are easy to catch, but humans often take the largest individual to feed many mouths or to display as a trophy."This preference for the biggest means the smaller individuals tend to survive and reproduce, which over time leads to the evolution of smaller individuals in the population. Sullivan's father was a hunter, and she remembers being intrigued as a child when he would choose to spare the lives of the largest bucks to keep this from happening in the local deer population.When she joined George Perry's lab at Penn State, they wrote a paper that reviewed 'the deep history of human entanglement' with animals and plants, and how these organisms have physically changed because of human behaviors. Sullivan hoped to write her dissertation about lemurs, which have become almost 10% smaller in only 1,000 years, presumably as a result of human hunting. But because lemurs are primates, endangered, and live in Madagascar, the logistics, not to mention the cost, of sampling modern and ancient lemur DNA were daunting.At the same time, Sullivan and Perry were fascinated by a study by a staff scientist at STRI, Aaron O'Dea, and colleagues, who showed that marine snails called fighting conch, commonly eaten as ceviche or fritters by Caribbean coastal residents, have steadily become smaller in areas where they were harvested for food. Modern shells contained 66% less meat than shells from ancient "pristine" reefs. The logistics of working at the Smithsonian's Bocas del Toro Research Station were straightforward, but no one had ever extracted DNA from tropical shells before -- modern or ancient."Most of the ancient DNA that had been sequenced was from animals or plants in permafrost which helps preserve the DNA," Sullivan said. "We had no idea whether DNA would survive in a tropical environment for thousands of years."The first step she took was to create a reference sequence from fresh conch tissue. She then moved to the shell itself. Since conch shells have much more calcium carbonate than bone, Sullivan had to modify a standard approach typically used to extract DNA from human skeletal material. This crucial step was recommended by Stephanie Marciniak, a specialist in ancient DNA and post-doctoral fellow in Perry's lab.After refining the approach, Sullivan then moved to thousand-year-old shells from a trash midden at the Sitio Drago archeological site in Bocas del Toro. This site had been studied by STRI Research Associate and UCLA Professor Tom Wake."Those shells had probably been cooked by their pre-Columbian harvesters making Alexis' successful extraction and sequencing of DNA even more incredible," Wake said.Finally, Sullivan turned to the same species of conch preserved in a mid-Holocene coral reef, again in Bocas del Toro. As they expected, the DNA was poorly preserved, but Sullivan demonstrated that even shells more than 7,000 years old faithfully preserved DNA."I was amazed," O'Dea said. "After 7,000 years in temperatures over 20 degrees Celsius, these conch shells still preserved minute fragments of the original animals' DNA. This work opens the door to exploring the genetic changes in the conch associated with size changes over millennia, and it's all down to Alexis' skill and perseverance."As the team learns more about the biology and genetics of the conch, they will be in a much better position to understand if human harvesting or something else explains why fighting conchs are smaller in areas where they are frequently harvested."We are especially grateful to the Cayo Agua community in Bocas del Toro who offered conch shells for our tests," Sullivan said. She hopes to return to Panama soon to share her results with them.
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222124703.htm
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New dating techniques reveal Australia's oldest known rock painting, and it's a kangaroo
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A two-metre-long painting of a kangaroo in Western Australia's Kimberley region has been identified as Australia's oldest intact rock painting.
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Using the radiocarbon dating of 27 mud wasp nests, collected from over and under 16 similar paintings, a University of Melbourne collaboration has put the painting at 17,500 and 17,100 years old."This makes the painting Australia's oldest known in-situ painting," said Postdoctoral Researcher Dr Damien Finch who pioneered the exciting new radiocarbon technique."This is a significant find as through these initial estimates, we can understand something of the world these ancient artists lived in. We can never know what was in the mind of the artist when he/she painted this piece of work more than 600 generations ago, but we do know that the Naturalistic period extended back into the Last Ice Age, so the environment was cooler and dryer than today."The Kimberley-based research is part of Australia's largest rock art dating project, led by Professor Andy Gleadow from the University of Melbourne. It involves the Balanggarra Aboriginal Corporation, the Universities of Western Australia, Wollongong, and Manchester, the Australian National Science and Technology Organisation, and partners Rock Art Australia and Dunkeld Pastoral.Published today in Nature Human Behaviour, Dr Finch and his colleagues detail how rock shelters have preserved the Kimberley galleries of rock paintings, many of them painted over by younger artists, for millennia -- and how they managed to date the kangaroo rock painting as Australia's oldest known in-situ painting.The kangaroo is painted on the sloping ceiling of a rock shelter on the Unghango clan estate in Balanggarra country, above the Drysdale River in the north-eastern Kimberley region of Western Australia.Earlier researchers looked at the stylistic features of the paintings and the order in which they were painted when they overlapped, and were able to work out from there that the oldest style of painting is what's known as the Irregular Infill Animal or the Naturalistic period, which often features life-size animals. This kangaroo is a typical example of paintings in this style.Dr Finch said it was rare to find mud wasp nests both overlying and underlying a single painting. For this painting they were able to sample both types to establish the minimum and maximum age for the artwork."We radiocarbon dated three wasp nests underlying the painting and three nests built over it to determine, confidently, that the painting is between 17,500 and 17,100 years old; most likely 17,300 years old."Dr Sven Ouzman, from University Western Australia's School of Social Sciences and one of the project's chief investigators, said the rock painting would unlock further understanding of Indigenous cultural history."This iconic kangaroo image is visually similar to rock paintings from islands in South East Asia dated to more than 40,000 years ago, suggesting a cultural link -- and hinting at still older rock art in Australia," Dr Ouzman said.Cissy Gore-Birch, Chair of the Balanggarra Aboriginal Corporation, said partnerships were important to integrate traditional knowledge with western science, to preserve Australia's history and cultural identity."It's important that Indigenous knowledge and stories are not lost and continue to be shared for generations to come," Ms Gore-Birch said. "The dating of this oldest known painting in an Australian rock shelter holds a great deal of significance for Aboriginal people and Australians and is an important part of Australia's history."The next step for the researchers, who are aiming to develop a time scale for Aboriginal rock art in the Kimberley, is to date further wasp nests in contact with this and other styles of Kimberley rock art to establish, more accurately, when each art period began and ended.
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222124605.htm
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Unique study of isolated bobcat population confirms accuracy of extinction model
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The reintroduction of 32 bobcats to an island off the coast of Georgia more than three decades ago created an ideal experiment to examine the accuracy of a genetic-modeling technique that predicts extinction of isolated wildlife populations.
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That's the conclusion of Penn State researchers who continue to monitor the bobcat population on Cumberland Island National Seashore, and who conducted a study comparing and contrasting the Cumberland Island bobcats to a population of bobcats on Kiawah Island off the coast of South Carolina.The research was led by Cassandra Miller-Butterworth, associate professor of biology at Penn State Beaver, and Duane Diefenbach, Penn State adjunct professor of wildlife ecology who, as a doctoral candidate at the University of Georgia in 1989, reintroduced bobcats captured on the Georgia mainland to Cumberland Island. Before freeing the bobcats on the island, he drew blood samples from the animals and froze them. DNA in those samples now serves as a baseline to compare how the population is faring.The bobcat reintroduction was part of Diefenbach's doctoral research, in which he documented the survival and reproduction of the reintroduced bobcats and collected blood samples from the first litters of kittens born on the island. Since then, he has returned to the island many times over the years with students and volunteers to collect bobcat scat from which to extract DNA to monitor the population's genetic health.There now are 24 bobcats on Cumberland Island, which is separated from the mainland by open water that prevents bobcats from the mainland from immigrating. DNA from the scat allows the scientists to identify individual bobcats, which enables them to estimate abundance and survival rates and measure levels of inbreeding."Because we had DNA from the founding population, we were able to document the loss in genetic diversity over time in the population," said Diefenbach, leader of the Pennsylvania Cooperative Fish and Wildlife Research Unit, which is housed in Penn State's College of Agricultural Sciences. "Over the past 30 years, the population has lost about 15% of its genetic diversity. There appears to be some inbreeding, but generally it is low."Over the last decade, Diefenbach has collaborated with Miller-Butterworth, a wildlife population geneticist, to analyze the bobcats' DNA. Her laboratory handled all the molecular analyses from the blood samples.Diefenbach and Miller-Butterworth also assessed the bobcat population on Kiawah Island. After trappers in 2015 and 2016 donated tissue samples from bobcats on the South Carolina mainland, the researchers determined that bobcats do occasionally travel on and off that island, likely over a bridge for vehicles."On Kiawah, we studied the genetics and found that about every five years, a bobcat from the mainland contributes genes to the island population," Miller-Butterworth said. "Consequently, genetic diversity on Kiawah Island is lower than on mainland South Carolina, but still higher than on Cumberland Island."The research findings, recently published in However, the findings provide good news for people trying to protect endangered species, Miller-Butterworth pointed out."We found that population viability models that predict the fate of the population did a good job in predicting the loss in genetic diversity and the long-term population size," she said. "I was surprised at how closely the modeling data and the empirical data matched -- you don't see that often. When we were running the population viability analyses, the predictions that we got for genetic variation, or heterozygosity, matched almost exactly what we were finding with our empirical DNA data."The Cumberland Island bobcat study is valuable because it yielded information that may be useful in future research used to rescue endangered felid populations, such as Iberian lynx or Eurasian lynx, for which extinction risk may be high, Miller-Butterworth explained. Bobcats are not threatened as a species, but the isolated population on Cumberland Island simulates an endangered species scenario in which a population becomes isolated due to habitat loss and fragmentation and loses genetic variation over time -- an increasingly common scenario for many endangered species."The benefit is we can use this as a case study, or a test case, to figure out what works to re-establish the population's viability, and then that knowledge potentially can be used to extrapolate what would work for an endangered species where the situation is dire," she said. "If we make a mistake in our calculations on Cumberland Island, it would be sad, but it wouldn't result in losing a species."
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222124540.htm
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'Jumping genes' repeatedly form new genes over evolution
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In the same way that Lego pieces can be arranged in new ways to build a variety of structures, genetic elements can be mixed and matched to create new genes, according to new research.
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A long-proposed mechanism for creating genes, called exon shuffling, works by shuffling functional blocks of DNA sequences into new genes that express proteins.A study, "Recurrent Evolution of Vertebrate Transcription Factors by Transposase Capture," published Feb. 19 in Transposons, first discovered in the 1940s by Cornell alum and Nobel Prize-winner Barbara McClintock '23, M.A. '25, Ph.D. '27, are abundant components of genomes -- they make up half of human DNA -- and have the ability to hop and replicate selfishly in the genome. Some transposons contain their own genes that code for enzymes called transposase proteins, which cut and paste genetic material from one chromosomal location to another.The study, which focused on tetrapods (four-limbed vertebrates), is important because it shows that transposons represent an important force in the creation of new genes during evolution. The work also explains how genes critical for human development were born."We think it's very likely this mechanism may extend beyond vertebrates and could be more of a fundamental mechanism that occurs in non-vertebrates as well," said first author Rachel Cosby, Ph.D. '19, a postdoctoral researcher at the National Institutes of Health. Cosby is a former graduate student in the lab of senior author Cedric Feschotte, professor in the Department of Molecular Biology and Genetics in the College of Agriculture and Life Sciences."You are putting the bricks in in a different way and you construct a whole new thing," Feschotte said. "We are looking at the question of how genes are born. The originality is that we are looking at the role of transposons in creating proteins with novel function in evolution."In the study, the researchers first mined existing databases for genomes of tetrapods, because genomes for more than 500 species have been fully sequenced. Cosby and colleagues searched for combinations of DNA sequences known to be characteristic of transposons fused to host sequences to find good candidates for study. They then chose genes that evolved relatively recently -- within tens of millions of years ago -- so they could trace the history of the gene's development through the vertebrate tree of life.Though genes fused with these transposases are relatively rare, the researchers found them all over the vertebrate tree of life. The researchers identified more than 100 distinct genes fused with transposases born in the past 350 million years along different species lineages, including genes in birds, reptiles, frogs, bats and koalas, and a total of 44 genes born this way in the human genome.Cosby and colleagues selected four recently evolved genes and performed a wide range of experiments in cell culture to understand their functions. They found the proteins derived from these genes are able to bind to specific DNA sequences and turn off gene expression. Such genes are known as transcription factors and act as master regulator genes for development and basic physiology. One such gene, PAX6, is well studied, plays a key role as a master regulator in the formation of eyes in all animals and is highly conserved throughout evolution."If you put a PAX6 gene from a mouse into a Drosophila [fruit fly], it works," Feschotte said. Though others have proposed before that PAX6 is derived from a transposase fusion, the researchers in this study further validated the hypothesis.Cosby and colleagues isolated one of these recently evolved genes in bats, called KRABINER, and then used CRISPR gene-editing technology to delete it from the bat genome and see what genes were affected, before adding it back in. The experiment revealed that when KRABINER was removed, hundreds of genes were dysregulated, and when they restored it, normal functioning returned. The protein expressed by the KRABINER gene bound to other related transposons in the bat genome, Cosby said."The experiment revealed that it controls a large network of other genes wired through the past dispersion of related transposons throughout the bat genome -- creating not just a gene but what is known as a gene regulatory network," Feschotte said.Current and former Feschotte lab members Julius Judd, Ruiling Zhang '20, Alan Zhong '19, Nathaniel Garry '21 and collaborator Ellen Pritham are co-authors of the paper.The study was funded by the National Institutes of Health.
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222095019.htm
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A novel gene discovery associated with a development disorder of pituitary origin
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The pituitary gland is a pea-sized endocrine gland composed of two structurally and functionally separate parts known as anterior and posterior lobes. The pituitary gland's anterior lobe secretes six hormones essential to growth, reproduction, and other basic physiological functions. Abnormal development of the pituitary gland, or hypopituitarism, can cause mild or complete deficiency of one or more pituitary hormones, which manifests as highly varying symptoms. Tumours mainly cause hypopituitarism in humans, but a congenital factor can also be associated with the disorder.
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The POU1F1 gene regulates the development of the anterior pituitary lobe, and disruption to its function results in hormonal changes, evidenced in affected dogs as dwarfism and coat abnormalities. A gene test developed based on the findings supports diagnostics and a breeding programme to eradicate the disease from the breed."Roughly 30 genes have been associated with inherited hypopituitarism in humans, many of which are regulator genes, which affect the development of the pituitary gland. In addition to humans, impaired pituitary function occurs in mice and dogs. In German Shepherds, hypopituitarism has previously been associated with the LHX3 gene, while in the case of Karelian Bear Dogs, the disease was described in Denmark already 45 years ago. Now, we have identified a related cause in the POU1F1 gene. This is only the second new canine model for human pituitary disease, making it quite significant," says Professor Hannes Lohi.Samples for the study were collected from Finnish and Swedish symptomatic and asymptomatic Karelian Bear Dogs."We managed to get samples from a total of eight sick puppies from five different litters. The puppies were as much as 20 centimetres smaller than normal, with many of them also having a puppy-like coat or substantial hair loss. Typical of the disease, their symptoms were varied. A handful of carriers of the POU1F1 variant were also found in Lapponian Herders in an analysis encompassing more than 8,000 dogs," says Kaisa Kyöstilä, PhD, the first author of the article.The study confirmed that the disease is inherited recessively, meaning that the affected dogs inherit the gene variant from both parents. Among Karelian Bear Dogs, only 8% of the breed carries the defect, and carriers do not develop the disease. The gene test based on the research finding can be used to identify carriers, avoid carrier-carrier combinations in breeding and eradicate this severe disease from the breed altogether.The latest POU1F1 gene discovery is already the third disease gene described in Karelian Bear Dogs. The research group has previously described gene finds associated with dwarfism (link in Finnish only) and hypophosphatasia.
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222095046.htm
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Researchers 'cautiously optimistic' about desert bighorn sheep recovery in Mojave Desert
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Desert bighorn sheep in the Mojave National Preserve in California and surrounding areas appear to be more resilient than previously thought to a respiratory disease that killed dozens of them and sickened many more in 2013, a new study has found.
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Clint Epps, a wildlife biologist at Oregon State University, and several co-authors, found that exposure to one of the bacteria associated with the disease is more widespread among bighorn sheep populations in the Mojave, and that its presence dates further back, than scientists thought. But they also found that the overall number of infected bighorn has declined since 2013 in the populations surveyed.Epps and his colleagues, including Nicholas Shirkey, an environmental scientist with the California Department of Fish and Wildlife and lead author of the paper in the "I wouldn't let my guard down, but I have been heartened to see that the bighorn are hanging on," said Epps, a professor in OSU's College of Agricultural Sciences.The 2013 respiratory disease outbreak puzzled scientists, who grew concerned that the disease could impact the long-term future of one of the few large mammals that can live in this harsh desert environment. Desert bighorn sheep, which weigh up to 250 pounds, are notable for their large curled horns and ability to climb steep, rocky terrain with speed and agility. They live in California, Nevada, Utah, Arizona, New Mexico and Texas, as well as Mexico.Epps, who began studying desert bighorn sheep in 1999, said they are a species that brings people together."I've seen people from all walks of life -- people who are hunters, people who are desert aficionados, people who love biodiversity, people who just love these things for their iconic beauty -- all coming together around the conservation management of this species," he said. "I have seen some really unusual partnerships."Shirkey added that the rare animals captivate people. "There's fewer than 5,000 desert bighorn in the state of California," he said. "There's probably that many deer in parts of some counties. They live in small numbers in very difficult places and even just seeing one, you feel like you've gotten to have a real special experience."The paper, published in the The 2013 outbreak of the pathogen mobilized interest in the Mojave populations of desert bighorn sheep, leading the California Department of Fish and Wildlife, the National Park Service, Epps and other partners to capture and release more animals to obtain blood samples to check their health and monitor population trends.The Mojave Desert occupies about 43,000 square miles, of which 59% is in California. The California piece of the Mojave is about the size of the state of West Virginia. That large size leads to distinct, though connected, populations of desert bighorn sheep throughout the Mojave in California. The California Department of Fish and Wildlife has captured sheep in 16 different mountain ranges.In 2013, they captured 70 desert bighorn sheep in eight of those populations. Sixty percent of them had antibodies to Mycoplasma ovipneumoniae, the pathogen that causes the respiratory diseases. In four subsequent years of capturing bighorn sheep in up to 12 of those regions, between 12% and 15% had the antibodies. While the percentage of bighorn with antibodies has declined across most populations since 2013, the researchers continue to identify additional ranges where the pathogen has been present.The researchers also tested blood samples that had been collected from desert bighorn sheep during the 1980s, 1990s and 2000s. The samples they tested, which are archived by the California Department of Fish and Wildlife, only represented four of the 16 populations.The researchers found evidence that bighorn sheep in those populations had been exposed to that pathogen in all three of those decades, leading them to question whether the antibodies were to the same strain as that observed during the 2013 outbreak or a less virulent strain. In one case, a population with evidence of exposure in 1989-90 appeared to have cleared the pathogen several years later, with subsequent tests failing to detect exposure until the 2013 outbreak."The findings in the paper show the importance of a sustained effort to collect data from these desert bighorn sheep," Epps said. "The data really help us understand what is happening with these populations so that we can make sure they survive."In addition to Epps and Shirkey, authors of the paper are: Annette Roug (shared first author), Thomas Besser, Vernon C. Bleich, Neal Darby, Daniella Dekelaita, Nathan Galloway, Ben Gonzales, Debra Hughson, Lora Konde, Ryan Monello, Paige R. Prentice, Regina Vu, John Wehausen, Brandon Munk (shared senior author) and Jenny Powers (shared senior author.)Funding for the research was provided by California Department of Fish and Game Federal Aid in Wildlife Restoration Project, Boone and Crockett Club, California Association of Professional Scientists, Foundation for North American Wild Sheep, National Rifle Association, Safari Club International, San Bernardino County Fish and Game Commission, Society for the Conservation of Bighorn Sheep, U.S. Department of Interior Bureau of Land Management, California Department of Fish and Wildlife, National Park Service, Oregon State University, Nevada Department of Wildlife, California Chapter of the Wild Sheep Foundation and the Desert Bighorn Council.
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Animals
| 2,021 |
February 22, 2021
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https://www.sciencedaily.com/releases/2021/02/210222092311.htm
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Electrical transmission lines have power to enhance habitat connectivity for wildlife
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Converting the ground under electrical transmission towers into spaces for wildlife can enable fragmented populations to connect with one another, increasing local biodiversity and providing animals around the globe an important tool for adapting to climate change, a new study found.
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"The most common way species respond to climate change is to try to shift their range -- i.e., go live somewhere else," Oregon State University scientist Virginia Morandini said. "When landscapes become fragmented, usually because of human activity, it greatly hinders animals' ability to move their range. That's why it's so important for biodiversity conservation to try to get their environments connected."For this study, Morandini teamed up with scientists from the Estacio?n Biolo?gica de Don?ana (Biological Station of Don?ana) in Seville, Spain, to plant native shrubs and seedlings under six towers in two 400-kilovolt lines running parallel through cereal cropland in Spain's Andalusia region. The area of each tower base is 100 square meters.Compared to each of four control sites -- two unmodified tower bases, plus two other unmodified 100-square-meter parcels nearby -- the researchers measured increased population density and diversity among the eight arthropods and four species of small mammals, including rats, mice, insects and spiders, that they trapped during the four-year study.The numbers of bird species and total birds observed rose as well, likely in connection with the other increases, said Morandini, a postdoctoral researcher in the OSU College of Agricultural Sciences.Land-use changes and climate change, in that order, are the two main causes for wildlife habitat loss around the world, Morandini notes. By the end of this century, climate change may take over the top spot."The construction of connected environments that enable species to follow the pace of climate change and thus decrease their extinction risk is a commonly voiced conversation strategy," she said. "Enhancing connectivity through networks of habitat corridors or stepping-stone patches has become a key concept in conservation biology and landscape ecology. That would increase resilience by boosting biological processes like dispersal and gene flow, allowing for recovery of small populations and spatial redistribution of populations."Highly mobile species like birds are somewhat able to deal with habitat fragmentation, but the species that Morandini and collaborators measured in this study are much less equipped to do so.Buying or renting large parcels of land to connect protected natural areas to one another would be cost prohibitive, but power transmission networks -- with towers every 200 meters of line -- are already in place in the developed nations where species are most affected by fragmentation."We wanted to see if the networks that carry electricity from power plants to substations could double as biodiversity reserves for small animals, using the tower bases to make a kind of rosary of diversity spots," Morandini said. "The European Union has 200,000 kilometers of transmission lines and the United States has 254,000. That means the EU has 1 million towers and the U.S. has 1.27 million, with 100 million and 127 million square meters of base area, respectively. That's a lot of room for native plants and wildlife habitat."Generally speaking, a power company pays rent to landowners, often farmers or agribusinesses, for the right to place towers on their land. Because it's hard to work the area under a tower with farm equipment, the owner usually doesn't use that space, opening the door to low-cost efforts by conservationists. The scientists spent roughly 450 Euros ($545 in U.S. dollars) per tower to effect the modifications, with no ongoing maintenance costs to speak of."We showed by modifying the tower bases as we did we were able to increase the density and diversity of several species of invertebrates and small mammals," Morandini said. "We could also make other types of modifications appreciated by different target animals. For example, including some water would help amphibians move though the power lines. Amphibians are among the groups most affected by global warming and landscape fragmentation."Miguel Ferrer of the Estacio?n Biolo?gica de Don?ana led the study, with his colleagues Manuela De Lucas and Elena Hinojosa joining him and Morandini in the collaboration.Red Ele?ctrica de Espan?a, a public-private power company in Spain, provided funding. Findings were published in
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Animals
| 2,021 |
February 19, 2021
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https://www.sciencedaily.com/releases/2021/02/210219124242.htm
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Animal evolution: glimpses of ancient environments
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Although amber looks like a somewhat unusual inorganic mineral, it is actually derived from an organic source -- tree resins. Millions of years ago, when this aromatic and sticky substance was slowly oozing from coniferous trees, insects and other biological material could become trapped in it. That is why some samples of amber contain fossilized specimens, preserved in a virtually pristine state, which afford fascinating snapshots of the flora and fauna of long-gone forests. Now, a research team led by LMU zoologists Viktor Baranov and Joachim Haug has made exciting finds in samples of amber from the Baltic region and Myanmar, which provide new insights into the ecology of two groups of ancient insects.
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In the Eocene period -- between 56 and 33.9 million years ago -- the Baltic amber forests covered (most likely around 38 million years ago) large areas of what is now Northern Europe, and were the source of most amber found in Europe. In one sample, the LMU team identified no less than 56 fly larvae, all of which were entombed while feasting on a single chunk of mammalian dung. "This fossil is particularly interesting, because the dung is full of plant residues, which implies the presence of at least moderately large herbivores in these forests," Baranov explains. On this basis, he and his colleagues assume that there must have been open areas of grassland nearby, corroborating earlier hypotheses. "The Baltic amber forest is often portrayed as a densely overgrown and humid jungle landscape. But it is much more likely that it was a more open, warm-to-temperate habitat," Baranov says.In other samples, the researchers found insect larvae whose modern descendants are mainly found in association with plants that are under chronic stress. "It has long been suspected that forests which produced large amounts of amber were ecologically under stress," says Haug. "That would be perfectly compatible with the presence of these larvae." High temperature and dry conditions are the most probable source of such stress.The unusual butterfly larva that Haug identified in amber from Myanmar is considerably older than the specimens from the Baltic. It dates to the Cretaceous, more than 100 million years ago, at a time when dinosaurs still dominated the Earth. Up until now, only four caterpillars from the Cretaceous had been discovered, and the new find is very different from all of them. "All of the previously discovered caterpillars were relatively naked," says Haug. "Our caterpillar is the first 'armored' specimen that has turned up -- it bears spines dorsally on some of its segments." The new specimen thus supports the idea that butterflies underwent an early phase of diversification and also reveals some aspects of their ecology. In modern caterpillars, such spines serve as a deterrent to predators -- more particularly, songbirds. "The rapid diversification of birds first sets in after the demise of the large dinosaurs, but small birds that may have fed on caterpillars were already extant during the Cretaceous," Haug points out.
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Animals
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February 19, 2021
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https://www.sciencedaily.com/releases/2021/02/210219095939.htm
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Ultraviolet 'television' for animals helps us better understand them
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University of Queensland scientists have developed an ultraviolet 'television' display designed to help researchers better understand how animals see the world.
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Until now, standard monitors on devices like televisions or computer screens have been used to display visual stimuli in animal vision studies, but none have been able to test ultraviolet vision -- the ability to see wavelengths of light shorter than 400 nanometres.Dr Samuel Powell, from the Queensland Brain Institute's Marshall lab, said this new technology will help unveil the secrets of sight in all sorts of animals, such as fish, birds and insects."Human TVs generally use three colours -- red, green and blue -- to create images, but our newly-developed displays have five, including violet and ultraviolet," Dr Powell said."Using this display, it's now possible to show animals simple shapes, to test their ability to tell colours apart, or their perception of motion by moving dot patterns."We affectionately call it the 'UV-TV', but I doubt that anyone would want one in their home!"You'd have to wear sunglasses and sunscreen while watching it, and the resolution is quite low -- 8 by 12 pixels in a 4 by 5 centimetre area -- so don't expect to be watching Netflix in ultraviolet anytime soon."This very low resolution is enough to show dot patterns to test fish perception, in what's known as an Ishihara test, which would be familiar to anyone who's been tested for colour blindness."In this test, humans read a number hidden in a bunch of coloured dots, but as animals can't read numbers back to us, they're trained to peck the 'odd dot' out of a field of differently coloured dots."Dr Karen Cheney from UQ's School of Biological Sciences said this technology will allow researchers to expand our understanding of animal biology."There are many colour patterns in nature that are invisible to us because we cannot detect UV," Dr Cheney said."Bees use UV patterns on flowers to locate nectar, for example, and fish can recognise individuals using UV facial patterns."We've recently started studying the vision of anemonefish or clownfish -- aka, Nemo -- which, unlike humans, have UV-sensitive vision."Our research is already showing that the white stripes on anemonefish also reflect UV, so we think UV colour signals may be used to recognise each other and may be involved in signalling dominance within their social group."Who knows what other discoveries we can now make about how certain animals behave, interact and think."This technology is allowing us to understand how animals see the world, helping answer significant questions about animal behaviour."
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Animals
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February 19, 2021
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https://www.sciencedaily.com/releases/2021/02/210219083848.htm
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Quartz crystals in the stomach of fossil bird complicates the mystery of its diet
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It's hard to know what prehistoric animals' lives were like -- even answering seemingly simple questions, like what they ate, can be a challenge. Sometimes, paleontologists get lucky, and pristine fossils will preserve an animal's stomach contents or provide other clues. In a new study in
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"I would say it's some kind of bizarre form of soft tissue preservation that we've never seen before," says Jingmai O'Connor, the associate curator of fossil reptiles at Chicago's Field Museum. "Figuring out what's in this bird's stomach can help us understand what it ate and what role it played in its ecosystem.""This paper tells us that the Enantiornithes, one important clade of fossil birds, still have no direct stomach traces or evidence," says Shumin Liu, a student at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and the paper's first author. "I was excited, it is a breakthrough about them."The fossil bird the researchers focused on is a specimen of Despite the vast number of finely preserved enantiornithines, none have been preserved with traces of food in their stomachs that could tell researchers what these birds ate. "We can identify the diet and reconstruct the digestive system for all these other groups of birds found in the deposits that record the Jehol Biota, except the enantiornithines, even though you have more enantiornithines than any other group," says O'Connor. "For these guys, we have no specimens or preserved evidence of diet, which is really weird." In the specimen O'Connor and her colleagues examined in this new paper, though, there was a clue: a previous study pointed out the presence of small rocks in its stomach.Many living birds have an organ called a gizzard -- a thick, muscular part of the stomach helps them digest food. They swallow small rocks, called gizzard stones, and these rocks make their way to the gizzard, where they help to crush up tough food. These gizzard stones, called gastroliths, have been found in some dinosaur and bird fossils, providing clues about what those animals ate -- they've been associated with diets of tough plant materials and seeds.But rocks in an animal's stomach aren't necessarily a sign that it's using them to crush up food. Some modern birds of prey swallow rocks called rangle to help dislodge matter from their digestive tract to clean it out. And sometimes, rocks have been found near the stomach cavities of dinosaur fossils that the creature swallowed accidentally, or the stones were just coincidentally near the fossil. "You have to make a differentiation between just a gastrolith and a gastrolith that's used as a gizzard stone," says O'Connor.While there's no clear evidence of gastroliths in the enantiornithine birds, a paper published in 2015 posited that a specimen of The researchers extracted a sample of the rocks in Bohaiornis's stomach and examined them under a scanning electron microscope. They then exposed the rocks to X-rays to determine which wavelengths the rocks absorbed. Since each mineral absorbs different wavelengths, this helped the researchers narrow down what these rocks were made of."We found that those pieces of rock that had been called gastroliths were chalcedony crystals," says O'Connor. "Chalcedony is basically quartz crystals that grow in sedimentary rocks. There hasn't been any evidence of this in the Jehol but there's plenty of evidence of it within the fossil record where chalcedony crystals will form within a clamshell, or sometimes chalcedony will replace the minerals making up the bones in a fossil." What's more, the chalcedony was all interconnected in one thin sheet of crystal, rather than separate rocks that the bird had swallowed.The amount of chalcedony present was wrong, too, if it were used to help with digestion. Scientific literature suggests that the rocks that birds consume as rangle account for about 3% of their body mass; since Bohaiornis was likely about 300 grams, the team would be looking for up to 9 grams worth of rangle. O'Connor says, "We weren't able to extract the entire sample and figure out how much it weighed, but Shumin was really clever, and she took a piece of chalcedony that weighed 3 grams, and it was huge" -- way bigger than the combined size of the bits of chalcedony in Bohaiornis's stomach.The combined evidence suggests that Bohaiornis didn't have gastroliths for helping crush food or rangle to help clean out its stomach after all. Or, at least, this specimen of Bohaiornis doesn't contain those gastroliths."We just have this absence of evidence, and paleontologists always say absence of evidence is not evidence of absence. But I always counter with, whoever came up with that adage never imagined having thousands of specimens that are complete and articulated, some preserving soft tissue," says O'Connor. If Early Cretaceous enantiornithines did employ gastroliths, it's awfully strange that none of the thousands of fossils show them.O'Connor notes that while none of the enantiornithine birds from the Jehol Formation show evidence of stomach contents, there's one from Spain with bits of freshwater shellfish in its stomach. But the mystery of what Bohaiornis ate, and why none of the Jehol enantiornithines have anything in their stomachs, remains."This study is important because this fossil is the one and only fossil record of Enantiornithes containing possible gastroliths, even possible real stomach traces in the Jehol. What's more, only this clade of fossil birds don't have stomach traces so far, whereas most other clades have these traces," says Liu."We're always trying to find some evidence, and the specimens that have been suggested to fill this gap just unfortunately don't do it," says O'Connor. "It's just part of the paleo game, part of science -- constantly correcting. I'm happy when we don't understand things, because it means there's research to do, it's exciting."
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Animals
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February 18, 2021
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https://www.sciencedaily.com/releases/2021/02/210218160413.htm
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Is odor the secret to bats' sex appeal?
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When falling in love, humans often pay attention to looks. Many non-human animals also choose a sexual partner based on appearance. Male birds may sport flashy feathers to attract females, lionesses prefer lions with thicker manes and colorful male guppies with large spots attract the most females. But bats are active in the dark. How do they attract mates? Mariana Muñoz-Romo, a senior Latin American postdoctoral fellow at the Smithsonian Tropical Research Institute (STRI) and National Geographic explorer, pioneers research to understand the role of odors in bat mating behavior.
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"Aside from their genitalia, most male and female bat species look identical at first glance. However, a detailed examination during mating season reveals odor-producing glands or structures that are only present in male bats. Long interested in this understudied sexual difference, and working with long-nosed bats, Leptonycteris curasoae, in Venezuela, Muñoz-Romo discovered that males exhibit an odorous dorsal patch in the mating season consisting of a mixture of saliva, feces, urine and/or semen that seems to attract reproductive females.Later in Panama, Muñoz-Romo investigated the "perfumes" from smelly crusts that male fringe-lipped bats, Trachops cirrhosus, meticulously apply to their forearms during mating season. These studies deepened her interest in odor and its role in bat mating systems, and her conviction that odor may be bats' secret weapon to choosing a mate in the dark."Studies across a range of mammalian species show that just by smelling a potential mate, an individual can assess its sex, age, sexual receptiveness, health, social status, group membership and identity. This is a whole lot of personal information in one sniff, suggesting that odor may be a more important factor for mate choice and reproduction.Alongside STRI staff scientist Rachel Page and Boston University bat ecologist, Thomas H. Kunz, Muñoz-Romo combed through all published articles on the topic. Together, they found reports of odor-producing structures in 121 bat species from 15 different bat families. This represents nearly 10% of all known bat species and over 70% of bat families. Odors come from very different parts of bats' bodies, from their heads and mouths to their wings or genitalia. Not only are chemical signals potent and effective for communication in dark conditions, they also do not impede the bats' ability to fly."We believe that these key factors -- nocturnality and powered flight -- combined with scent-producing glands common across mammals, promoted the evolution of a great diversity of the odorous displaying structures we find in bats," Muñoz-Romo said.Although researchers know very little about these structures so far, the new review of the subject opens up promising new avenues for bat research. There are potentially many more odor-related structures waiting to be discovered."Future investigations should consider the importance of the timing of odor production and sexual behavior, because most of these traits are displayed during a specific and usually short time of the year -- the mating season," Muñoz-Romo said. "Answering new questions about the nature and development of the odorous traits, as well as understanding which traits female bats prefer, are key to understanding why differences between males and females evolved. We also want to understand the chemistry of bat perfumes -- what compounds make them attractive."In another recent publication, Muñoz-Romo, Page and colleagues suggest that the size of the odorous crusts found on the forearms of male T. cirrhosus allow females to evaluate potential mates during the time of year when they were fertile."While differences between males and females (sexual dimorphism) in bats have long been overlooked, new tools are giving us an ever-expanding window into their previously cryptic social lives," Page said. "The patterns revealed here sharpen the focus of investigations going forward, in particular highlighting the importance of seasonally present odor-producing glands and soft tissues. With so many bat species still to be studied, it will be extremely exciting to see what lies on the horizon. We only wish that our dear friend and colleague, Tom Kunz, whose insight inspired this work, had lived to see the publication of this review."Members of the research team are affiliated with STRI, Universidad de Los Andes (Venezuela) and Boston University. The work supporting this review was funded by these three institutions at different points in time.
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Animals
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February 18, 2021
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https://www.sciencedaily.com/releases/2021/02/210218140123.htm
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Wolves prefer to feed on the wild side
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When there is a choice, wolves in Mongolia prefer to feed on wild animals rather than grazing livestock. This is the discovery by a research team from the University of Göttingen and the Senckenberg Museum Görlitz. Previous studies had shown that the diet of wolves in inland Central Asia consists mainly of grazing livestock, which could lead to increasing conflict between nomadic livestock herders and wild predatory animals like wolves. The study has been published in the journal
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Around three million people live in Mongolia, making it the most sparsely populated country in the world. In addition, there are more than 40 million grazing animals. These animals are not just a source of food but also the only source of income for more than half of the population. Livestock cultivation is leading to a massive change in Mongolia's landscape: areas close to nature are increasingly being converted into pastureland: in fact, one third of the country is now used for this purpose. This inevitably leads to conflict with the indigenous wild animals, especially large predators such as the wolf.Biologist and forest scientist Nina Tiralla from the University of Göttingen studied the feeding behaviour of wolves for her Master's thesis. Together with colleagues from the Senckenberg Museum, she analysed 137 wolf droppings collected during fieldwork in Mongolia between 2008 and 2012. "We were able to show that 89 percent of the wolves' diet consisted of wild ungulates, predominantly Siberian roe deer," says Tiralla. "The remaining 11 per cent consisted of small mammals such as hares or mice." Even remnants of insects and berries could be detected in the faeces -- but there was no trace of farmed animals. "This was surprising for us because previous studies had shown grazing animals to be the main food source for wolves," says Tiralla.The key difference could lie in the situation of the animals: unlike the earlier studies on Mongolian wolves, the samples examined in this study come from near-natural regions with high species diversity. "Although there is also a supply of grazing animals here, the wolves seem to prefer wild animals such as the Siberian roe deer as prey, possibly because they are easier and less dangerous to hunt," the authors explain. They conclude that if wolves live in a near-natural and species-rich landscape with sufficient prey, they pose only a very low threat to grazing livestock. This could apply not only in Mongolia, but in principle also to other countries.
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Animals
| 2,021 |
February 18, 2021
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https://www.sciencedaily.com/releases/2021/02/210218094536.htm
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Increasingly fragmented tiger populations may require 'genetic rescue'
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Despite being one of the world's most charismatic species, tigers face uncertain futures primarily due to habitat fragmentation, human-wildlife conflict and poaching. As global tiger populations decline, so does their genetic diversity. But until now it's been unclear how the animals' dwindling numbers are affecting them at the genetic level.
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To find out, researchers at Stanford University, the National Centre for Biological Sciences, India, and various zoological parks and NGOs sequenced 65 genomes from four of the surviving tiger subspecies. Their findings confirmed that strong genetic differences exist between different tiger subspecies but showed, surprisingly, that these differences emerged relatively recently, as Earth underwent a major climatic shift and our own species grew increasingly dominant.The research, detailed in a new paper published this week in the journal "The increasing dominance of humans across the world means that our understanding of which attributes of species and populations are best suited to the Anthropocene becomes ever more important," said Hadly, referring to the proposed geological epoch marked by significant human impact on the environment."Some populations are well adapted to a future dominated by humans and our new climates and others are not, so any type of management of species should be informed by what we can glean from their genomes," added Hadly, who is also a senior fellow at the Stanford Woods Institute for the Environment. "Conservation genomics is far from a perfect science, but this tiger study hints at the power of adequate sampling across both the species range and its genome."The study reveals that the world's existing tiger subspecies began exhibiting signs of dramatic and recent contractions starting only around 20,000 years ago -- a period that coincided with both the global transition out of the Pleistocene Ice Age and the rise of human dominance in Asia. Each subspecies of tiger the team studied showed unique genomic signatures as a consequence of their increasing isolation from one another.For example, local environmental genomic adaptation to cold temperatures was found in the Siberian (or Amur) tigers, the northernmost tigers found in the Russian Far East. These adaptations were absent in the other tiger subpopulations studied. Tigers from Sumatra, meanwhile, showed evidence of adaptations for body size regulation, which could help explain their overall smaller size. Despite these adaptations, tigers from these populations have low genetic diversity, suggesting that if populations continue to decline, genetic rescue may need to be considered.One form that rescue might take is through the mating of different tiger subspecies together as a way of increasing their genetic diversity and protecting against the ill effects of inbreeding. Inbreeding occurs when populations are so small and isolated from other populations that related individuals breed with each other. Over time, this leads to lower genomic diversity and to the emergence of recessive diseases, physical deformities and fertility problems that often result in behavioral, health and population declines. Although increasing genetic diversity is one goal, another might be to select for inherited traits that confer higher survival in a changing world.Even Bengal tigers from India, which comprise about 70 percent of the world's wild tigers and exhibit relatively high genomic diversity compared to other subspecies, showed signs of inbreeding in some populations, the study concluded."Some Bengal tiger populations are essentially small islands surrounded by an inhospitable sea of humanity. These tigers cannot disperse and so have only their close relatives to choose as mates," Hadly said.While many studies investigating endangered species using genomics sequences from a single or just a few individuals, this work reiterates that individuals are not likely to be representative of a population or species status. Further work investigating the consequences of potential inbreeding and diversity declines across the subspecies are needed."As genomics has become available to conservation, it is apparent that collaborative studies to investigate the diversity within species are critical," said study first author Ellie Armstrong, a Stanford PhD student in Hadly's lab. "Inferences made from single genomes, while excellent additions to our knowledge of diversity in general, cannot be extrapolated to entire species, especially when using captive animals to infer adaptation to complex habitat change."
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Animals
| 2,021 |
February 18, 2021
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https://www.sciencedaily.com/releases/2021/02/210218094510.htm
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Oil spill has long-term immunological effects in dolphins
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A study published in
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Bottlenose dolphins from an area that received prolonged and heavy oiling were temporarily captured, sampled, and released as part of health assessment programs. The animals were compared with dolphins from an area where no oil was observed.Investigators documented immunological alterations in bottlenose dolphins tested up to a decade following the oil spill that were similar in nature to those immediately following the spill. The effects were seen even in dolphins born after the spill. The nature of the immunological effects observed in dolphins were also similar to those in mice experimentally exposed to oil in the lab.The findings suggest that there are long-term consequences of oil exposure on the mammalian immune system, with possible multigenerational effects."The parallel between findings in dolphins exposed following the
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Animals
| 2,021 |
February 17, 2021
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https://www.sciencedaily.com/releases/2021/02/210217175148.htm
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Wolves, dogs and dingoes, oh my
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Dogs are generally considered the first domesticated animal, while its ancestor is generally considered to be the wolf, but where the Australian dingo fits into this framework is still debated, according to a retired Penn State anthropologist.
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"Indigenous Australians understood that there was something different about the dingoes and the colonial dogs," said Pat Shipman, retired adjunct professor of anthropology, Penn State. "They really are, I think, different animals. They react differently to humans. A lot of genetic and behavioral work has been done with wolves, dogs and dingoes. Dingoes come out somewhere in between."Wolves, dogs and dingoes are all species of the canidae family and are called canids. In most animals, hybridization between closely related species does not happen, or like female horses and male donkeys, produce mules -- usually non-fertile offspring. However, many canid species, including wolves, dingoes and dogs, can interbreed and produce fertile offspring. Defining species boundaries in canids becomes more difficult.Domestic dogs came to the Australian continent in 1788 with the first 11 ships of convicts, but dingoes were already there, as were aboriginal Australians who arrived on the continent about 65,000 years ago. A large portion of dingoes in Australia today have domestic dog in their ancestry, but dingoes came to Australia at least 4,000 years ago according to fossil evidence. Shipman believes that date may be even earlier, but no fossils have yet been found."Part of the reason I'm so fascinated with dingoes is that if you see a dingo through American eyes you say, 'that's a dog,'" said Shipman. "In evolutionary terms, dingoes give us a glimpse of what started the domestication process."Shipman reports her analysis of wolves, dogs and dingoes in a January 2021 special issue of the Dingoes, and the closely related New Guinea singing dogs, look like the default definition of dog, but they are not dogs."There is a basic doggy look to dingoes," said Shipman.Genetically and behaviorally they differ from dogs and are more like wolves in their inability to digest starches and their relationships with humans.Most domestic dogs evolved along with humans as humans became agriculturalists and moved to a diet containing large amounts of starch, whether from maize, rice, potatoes or wheat. Their genome changed to allow the digestion of these starches. Dingoes, like wolves, have very few of the genes for starch digestion.While indigenous Australians stole dingo puppies from their dens and raised them, these puppies generally left human homes at maturity and went off to breed and raise offspring. The ability to closely bond with humans is limited in dingoes, although present in dogs. Native Australians also did not manipulate dingo breeding, which is a hallmark of domestication.Dingoes are also well-adapted to the Australian outback and fare well in that environment. Domestic dogs that become feral do not survive well in the outback."Aboriginal Australians were not well-regarded as holders of knowledge or special skill when Europeans came to the continent," said Shipman. "So, no one thought to ask them about dingoes. Even recently, asking aboriginals for their scientific or behavioral knowledge really was not common."However, aboriginal Australians have a long history of living with dingoes in their lives. Many people argue that dingoes are just dogs -- strange dogs, but just dogs, said Shipman. But, according to aboriginals, dingoes are not dogs.With dingoes showing behaviors somewhere between wolves and dogs and exhibiting only slight genetic ability to consume starchy foods or tolerate captivity, Shipman concluded that "A dingo is a wolf on its way to becoming a dog, that never got there."
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Animals
| 2,021 |
February 16, 2021
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https://www.sciencedaily.com/releases/2021/02/210216185907.htm
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New Australian fossil lizard
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Some of Australia's most famous animals -- wombat, platypus, kangaroos and the extinct marsupial tiger thylacine -- have been traced back to their fossil ancestors in remarkable finds in central South Australia.
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Now a remote expedition to a large inland salt lake in 2017 has sifted through remains unearthed in Namba Formation deposits to describe a tiny new skink, an ancestor of Australia's well-known bluetongue lizards -- to be named in honour of world-renown Flinders University lizard researcher Professor Mike Bull.The new species, unveiled in the Royal Society's Open Science today, is described as Australia's oldest -- a 25 million-year-old skink named Proegernia mikebulli after the late Flinders University Professor Mike Bull.It was found by Flinders University and South Australian Museum palaeontologists and volunteers at a rich fossil site on Lake Pinpa located on the 602,000 square hectare Frome Downs Station, seven hours drive north of capital city Adelaide.Following the crusted shoreline of a salt lake, the team homed in on a cross section of sediments where fossil excavations of ancestors of koala, a predatory bird, and fragments of a thylacine were previously unearthed. Remains of prehistoric fish, platypus, dolphins and crocodilians have also been found nearby."It was 45?C in the shade that day and hard work digging through the clay, but it was definitely worth it once the tiniest of bone fragments turned out to be those of the oldest Australian skink," says lead author palaeo-herpetologist Dr Kailah Thorn, who conducted the research at Flinders University as part of her PhD.The once-verdant interior of Australia is considered the cradle of Australia's unique fauna and in particular its reptile diversity."Fossil lizards are often too small to be identified when you're in the field. Lizard skulls are made of more than 20 individual bones that all disarticulate when they fossilise," says Dr Thorn, who now works as curator of the Edward de Courcy Clarke Earth Sciences Museum at the University of Western Australia.The discovery of the tiny fossil lizards in an area the size of one million soccer fields was enabled by building an understanding of the geology of the region, and targeting fossiliferous bands of silt to thoroughly sieve and sort back at the lab, she explains."These lizard fossils owe their discovery to the patient sorting of tiny bones," says lead author, vertebrate palaeontologist Flinders University Associate Professor Trevor Worthy. "A teaspoon holds hundreds of tiny bones -- all revealed in translucent splendour under a microscope.""Once every 30 spoons something else is found among the fish -- usually a tiny mammal tooth. But the 2017 discovery of the oldest skink was a golden moment for a palaentologist," he says.When researchers placed the fossil in the evolutionary tree of lizards, it was found to be an early member of the Australian skink subfamily Egerniinae -- the group now encompassing bluetongues, sleepy lizards (shinglebacks), land mullets and spiny-tailed skinks.The newly described lizard Proegernia mikebulli is named after the late Flinders University Professor Mike Bull, who passed away suddenly in late 2016.Inspired generations of Australian herpetologists, Professor Bull's wide-ranging research career centred on social skinks from the Egerniinae subfamily, their behaviour, parasites, and conservation."Our colleague Professor Bull's long-term ecological studies of sleepy lizards were a massive contribution to biology," says co-author Matthew Flinders Professor Mike Lee (Flinders University / SA Museum)."The fossil record is essentially data from a long-term natural ecological study, so its fitting that this fossil lizards is named after in honour of Mike."
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Animals
| 2,021 |
February 16, 2021
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https://www.sciencedaily.com/releases/2021/02/210216115020.htm
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Alligator hearts keep beating no matter what
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Mammals and cold-blooded alligators share a common four-chamber heart structure -- unique among reptiles -- but that's where the similarities end. Unlike humans and other mammals, whose hearts can fibrillate under stress, alligators have built-in antiarrhythmic protection. The findings from new research were reported Jan. 27 in the journal
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"Alligator hearts don't fibrillate -- no matter what we do. They're very resilient," said Flavio Fenton, a professor in the School of Physics at the Georgia Institute of Technology, researcher in the Petit Institute for Bioengineering and Bioscience, and the report's corresponding author. Fibrillation is one of the most dangerous arrhythmias, leading to blood clots and stroke when occurring in the atria and to death within minutes when it happens in the ventricles.The study looked at the action potential wavelengths of rabbit and young alligator hearts. Both species have four-chambered hearts of similar size (about 3 cm); however, while rabbits maintain a constant heart temperature of 38 degrees Celsius, the body temperature of active, wild alligators ranges from 10 to 37 degrees Celsius. Heart pumping is controlled by an electrical wave that tells the muscle cells to contract. An electrical signal drives this wave, which must occur in the same pattern to keep blood pumping normally. In a deadly arrhythmia, this electrical signal is no longer coherent."An arrhythmia can happen for many reasons, including temperature dropping. For example, if someone falls into cold water and gets hypothermia, very often this person will develop an arrythmia and then drown," Fenton said.During the study, the researchers recorded changes in the heart wave patterns at 38 C and 23 C. "The excitation wave in the rabbit heart reduced by more than half during temperature extremes while the alligator heart showed changes of only about 10% at most," said Conner Herndon, a co-author and a graduate research assistant in the School of Physics. "We found that when the spatial wavelength reaches the size of the heart, the rabbit can undergo spontaneous fibrillation, but the alligator would always maintain this wavelength within a safe regime," he added.While alligators can function over a large temperature range without risk of heart trauma, their built-in safeguard has a drawback: it limits their maximum heart rate, making them unable to expend extra energy in an emergency.Rabbits and other warm-blooded mammals, on the other hand, can accommodate higher heart rates necessary to sustain an active, endothermic metabolism but they face increased risk of cardiac arrhythmia and critical vulnerability to temperature changes.The physicists from Georgia Tech collaborated with two biologists on the study, including former Georgia Tech postdoctoral fellow Henry Astley, now assistant professor in the Biomimicry Research and Innovation Center at the University of Akron's Department of Biology."I was a little surprised by how massive the difference was -- the sheer resilience of the crocodilian heart and the fragility of the rabbit heart. I had not expected the rabbit heart to come apart at the seams as easily as it did," noted Astley.Lower temperatures are one cause of cardiac electrophysiological arrhythmias, where fast-rotating electrical waves can cause the heart to beat faster and faster, leading to compromised cardiac function and potentially sudden cardiac death. Lowering the temperature of the body -- frequently done for patients before certain surgeries -- also can induce an arrhythmia.The researchers agree that this study could help better understand how the heart works and what can cause a deadly arrhythmia -- which fundamentally happens when the heart doesn't pump blood correctly any longer.The authors also consider the research a promising step toward better understanding of heart electrophysiology and how to help minimize fibrillation risk. Until December 2020, when Covid-19 took the top spot, heart disease was the leading cause of death in the United States and in most industrialized countries, with more people dying of heart disease than the next two causes of death combined.Astley said the research provides a deeper understanding of the natural world and insight into the different coping mechanisms of cold- and warm-blooded animals.Co-author Tomasz Owerkowicz, associate professor in the Department of Biology at California State University, San Bernardino, considers the findings "another piece of the puzzle that helps us realize how really cool non-human animals are and how many different tricks they have up their sleeves."He expressed hope that more researchers will follow their example and use a non-traditional animal model in future research."Everyone studies mammals, fruit flies, and zebrafish. There's such a huge wealth of resources among the wild animals that have not been brought to the laboratory setting that have such neat physiologies, that are waiting to be uncovered. All we have to do is look," he said.
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Animals
| 2,021 |
February 16, 2021
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https://www.sciencedaily.com/releases/2021/02/210216093022.htm
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Water is a probable vector for mammalian virus transmission
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Water is a necessity for all life but its availability can be limited. In geographical areas experiencing dry seasons, animals congregate near the few freshwater sources, often reaching large densities. At these sites many animals from different species come to the same spots to drink, potentially operating as key locations for pathogen transmission within and between species. An international team of scientists lead by the German Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) suggests that viruses can use restricted freshwater sources as a vector to be spread among animals. The key prediction of this idea is that animal viruses remain stable and infectious in water. The team tested this idea by sampling water holes in ecosystems of Africa and Mongolia with pronounced dry seasons and growing viruses in such water. The scientific results demonstrated that this was indeed possible and are published in
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The distribution of freshwater varies geographically and seasonally, with places such as East Africa and Central Asia experiencing pronounced seasonal shortages. Water scarcity results in frequent, unstable congregations of numerous wildlife species in the vicinity of freshwater sources. The objective of the scientific research work was to determine whether viral stability in restricted water sources is sufficient for some mammalian viruses, thereby enabling their spread through the medium of water.Equine herpesviruses (EHV) were selected as a model as they are known to remain stable and infectious in water for weeks under laboratory conditions and circulate in wildlife in both Africa and Mongolia. "We knew from our previous work, particularly with zebras in Africa, that equids become stressed when they are forced to aggregate in the dry season. When we looked at the effects of stress in captive zebras, we could see that it was associated with shedding of EHVs into the environment. This suggested that just at the time when animals are forced to congregate, they are most likely to be stressed and shed viruses. The stress is acting as a sort of signal to the virus to get into the water to infect more individuals," says Prof Alex Greenwood, the leader of this scientific work."Congregations also help explain some odd results from both captive and free-living wildlife, such as the infection of non-equids with EHVs, for example, rhinos," explains Dr Peter Seeber from the Leibniz-IZW who collected water and zebra samples in East Africa. "If rhinos share the water with equids, they are likely exposed to the virus," adds Dr Sanatana Soilemetzidou form the Leibnz-IZW, who collected the water and animal samples in Mongolia.To be validated, the entire concept of water as a viral vector hinged on showing that EHV remain stable in environmental water. "We were unsure what to expect given that culturing viruses from the environment is challenging given all the other microbes that can grow when you try to isolate a virus," comments Dr Anisha Dayaram, the lead author from the Leibniz-IZW. Dayaram and her colleagues succeeded in doing exactly that, using the water samples collected from both Africa and Mongolia. Under cell culture conditions they demonstrated that EHVs could indeed replicate and remained infectious.This seems to explain the rather odd result that EHVs seem to show limited viral evolution. Viruses tend to evolve rapidly but EHVs change little over time and are in this sense surprisingly stable. The EHVs found in Mongolia and Africa are nearly identical to those in domestic horses. This may represent a constraint or equilibrium state for the EHV found in water holes. "Our results suggest that the stability of EHV in water may be the result of a long evolutionary process, which has led such viruses to be truly adapted to using water as a vector," explains Dr Alexandre Courtiol, another Leibniz-IZW scientist involved in this scientific work.EHVs are not the only viruses that can be shed into and spread through water. Further research should uncover whether other viruses may use water in a similar way as vector to spread among animals. The work also suggests that understanding viral dynamics will require looking beyond virus host interactions in some cases and should include adaptations to transmission via the environment.
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Animals
| 2,021 |
February 15, 2021
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https://www.sciencedaily.com/releases/2021/02/210215131224.htm
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Tropical paper wasps babysit for neighbors
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Wasps provide crucial support to their extended families by babysitting at neighbouring nests, according to new research by a team of biologists from the universities of Bristol, Exeter and UCL published today [15 February] in
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The findings suggest that animals should often seek to help more distant relatives if their closest kin are less in need.Dr Patrick Kennedy, lead author and Marie Curie research fellow in the School of Biological Sciences at the University of Bristol, said: "These wasps can act like rich family members lending a hand to their second cousins. If there's not much more you can do to help your immediate family, you can turn your attention to the extended family."By closely observing twenty thousand baby wasps and their carers on colonies around the Panama Canal, the research team could determine the usefulness of workers on colonies of different sizes. They showed that workers become less useful as the number of colony members rises, due to a surplus of help.Andy Radford, Professor of Behavioural Ecology, also from Bristol and co-author, explained: "By helping more distant relatives who are more in need -- those living next door with fewer carers -- workers can pass on more copies of their genes overall. We believe that similar principles of diminishing returns might explain seemingly paradoxical acts of altruism in many other social animals."Dr Kennedy added: "The fact that these paper wasps in Central and South America help at other colonies is really bizarre when you consider that most wasps, ants and bees are extremely hostile to outsiders. To solve this puzzling behaviour, we combined mathematical modelling with our detailed field observations."Dr Kennedy continued: "We ended up being stung a lot. But it was worth it, because our results show that worker wasps can become redundant at home. A wasp on a colony with few larvae but lots of other workers becomes almost useless: the best thing to do is to babysit the larvae of other relatives."Since Darwin, biologists have been trying to understand how 'altruism' evolves in animals. At first glance, acts of selflessness to help other individuals do not seem to allow individuals to pass on their genes.Professor Radford said: "In 1964, the legendary biologist W. D. Hamilton figured out the cardinal rule of animal altruism. Lavish help on your family because they share many of your genes. Copies of your genes will triumph in the population."But the tropical paper wasps studied by the team baffled Hamilton back in 1964. In Brazil, he was surprised to notice that Polistes wasps were leaving their close family on their home nests and flying off to help the neighbours, who are less closely related.Previous work by co-author Seirian Sumner, Professor of Behavioural Ecology at University College London, showed that over half the workers in a Panamanian population were helping on multiple nests. Wasps usually viciously attack outsiders, so this babysitting suggested something unusual was going on.Professor Sumner explained: "Wasps offer amazing windows into the evolution of selflessness. There is so much going on in a wasp nest: power struggles, self-sacrifice, groups battling against the odds to survive... If we want to understand how societies evolve, we should look more deeply at wasps."This fieldwork was supported by the National Geographic Society and the Smithsonian Tropical Research Institute in Panama.
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Animals
| 2,021 |
February 12, 2021
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https://www.sciencedaily.com/releases/2021/02/210212123521.htm
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Study contradicts belief that whales learn songs from one another
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Humpback and bowhead whales are the only mammals other than humans thought to progressively change the songs they sing through a process of cultural learning.
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But maybe the humpbacks are no longer part of that trio. Humpbacks might be singing songs that are not as "cultured" as once assumed.A new study by a University at Buffalo researcher is directly contradicting the widely accepted cultural transmission hypothesis suggesting that whales learn their songs from other whales."It seems like that is not correct," says Eduardo Mercado, a professor of psychology in UB's College of Arts and Sciences. "Our findings indicate that neither cultural transmission nor social learning contributes significantly to how humpback whales change their songs over time."I think the results are provocative and will probably make other whale researchers livid or dismissive, but at least the discussion won't be boring!"The study, published Tuesday (Feb. 9) in the "The idea that humpback whales are a distinguished part of the animal kingdom because of their ability to culturally learn songs is apparently not true," says Mercado. "But to me, what the whales are doing is actually more impressive."Cultural transmission implies that what's heard is copied. That means it doesn't matter what is heard or what is copied. But what we found is very specific and precise, without a trace of arbitrary vocalization. The songs change over time in a fashion that's even more precise than what humans do when language develops."The talented club DJ serves as an appropriate metaphor for changing whale song."DJs can't just randomly go from one song to the next," says Mercado. "They have to think about beat matching, tempo and mood in order to maintain a continuous flow."I think that might be true of the whales. When they make changes, they do so in relation to what preceded it. They're basically beat matching when they change songs -- and we found similarities in populations that had no social contact or genetic links."Mercado says existing research claims that humpback populations isolated from one another do not change their songs in the same way. Each population is original, taking their songs in original directions."These things are not true," says Mercado. "I compare songs over 40 years and compare populations that have never been in contact with one another, and they're doing basically the same thing."Despite large and sometimes rapid changes, whales often end up singing similar songs, according to Mercado. The cultural transmission hypothesis is attractive in part because it's hard to imagine what mechanism might instigate the song variation.But previous research has relied heavily on subjectively defined categories. Songs sounding like a human snore would be placed in a "snore" category. Any subsequent analysis would depend on how well the categories captured the intricacies of the song."I didn't categorize things at all and used purely acoustic measurements," says Mercado, who specifically chose published records of data to avoid any suggestion of cherry picking the data. "This paper is based on direct measurements of sound features without any categorization or subjective labeling."Mercado says the results of the current study question the role of vocal imitation and cultural transmission in humpback whale song, but they do not resolve why the songs are changing."These results tell me that whales are sophisticated in ways that researchers and observers hadn't previously considered," says Mercado. "What we're hearing is a level of acoustic sophistication which is beyond the ability of humans."That's something that deserves both appreciation and further study. I'd like to examine why whale song changes and explore the benefit of that change."
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Animals
| 2,021 |
February 12, 2021
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https://www.sciencedaily.com/releases/2021/02/210212111914.htm
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Scientists identify how harmless gut bacteria 'turn bad'
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An international team of scientists has determined how harmless E. coli gut bacteria in chickens can easily pick up the genes required to evolve to cause a life-threatening infection. Their study, published in
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E. coli is a common bacterium that lives in the intestines of most animals, including humans. It is usually harmless when it stays in the gut, however it can become very dangerous if it invades the bloodstream, causing a systemic infection that can even lead to death.Avian pathogenic E.coli (APEC) is most common infection in chickens reared for meat or eggs. It can lead to death in up to 20 per cent of cases and causes multi-million pound losses in the poultry industry. The problem is made worse by increasing antibiotic resistance and infections also pose a risk of causing disease in humans.The team of scientists, led by the Milner Centre for Evolution at the University of Bath, sequenced and analysed the whole genomes of E. coli bacteria found in healthy and infected chickens bred at commercial poultry farms to better understand why and how these normally innocuous bugs can turn deadly.They found there was no single gene responsible for switching a harmless bacterium into a pathogenic one, but rather that it could be caused by several combinations of a diverse group of genes.Their results indicate that all bacteria in chicken intestines have the potential to pick up the genes they need to turn into a dangerous infection, through a process called horizontal gene transfer.Horizontal gene transfer enables bacteria to acquire new genetic material from other bacteria nearby. This can happen by scavenging DNA molecules from dead bacteria; by exchanging strands of DNA by having 'bacterial sex' or by getting infected by viruses which transfer DNA from one bacterium to another.Professor Sam Sheppard, from the Milner Centre for Evolution at the University of Bath, led the study. He said: "Previously we thought that E. coli became pathogenic by acquiring specific genes from other bugs, often packaged in mobile elements called plasmids."But our study compared the genomes of disease-causing and harmless E. coli in chickens and found that they can 'turn bad' simply by picking up genes from their environment."Bacteria do this all the time inside the guts of chicken, but most of the time the scavenged genes are detrimental to the bacteria so it becomes an evolutionary dead end."However, there are 26 billion chickens worldwide, representing around 70 per cent of all bird biomass on earth."That increases the likelihood of bacteria picking up genes that could help the bacteria survive and turn infectious, or even jump species to infect humans."The study authors stress the need to monitor strains that are most likely to become pathogenic so can treat them before they become dangerous.Professor Sheppard said: "We were surprised to find that it's not just a single strain that causes APEC, but any strain can potentially acquire the 'monster combination' of genes needed to turn bad."Strains with the potential to turn pathogenic could be identified using a similar method to that used to detect variant strains of Covid19. After whole genome sequencing, rapid PCR tests can be used to probe for specific genes that could lead to an APEC infection.Professor Sheppard said: "We identified around 20 genes that are common in pathogenic bugs and if we can look out for these key genes in a flock of birds, that would help farmers target those carriers before they cause a problem."
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Animals
| 2,021 |
February 12, 2021
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https://www.sciencedaily.com/releases/2021/02/210212094110.htm
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Lemurs show there's no single formula for lasting love
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Humans aren't the only mammals that form long-term bonds with a single, special mate -- some bats, wolves, beavers, foxes and other animals do, too. But new research suggests the brain circuitry that makes love last in some species may not be the same in others.
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The study, appearing Feb. 12 in the journal Red-bellied lemurs and mongoose lemurs are among the few species in the lemur family tree in which male-female partners stick together year after year, working together to raise their young and defend their territory.Once bonded, pairs spend much of their waking hours grooming each other or huddled side by side, often with their tails wrapped around each other's bodies. Males and females of these species spend a third of a lifetime with the same mate. The same cannot be said of their closest relatives, who change partners often.To biologists, monogamy is somewhat a mystery. That's in part because in many animal groups it's rare. While around 90% of bird species practice some form of fidelity to one partner, only 3% to 5% of mammals do. The vast majority of the roughly 6,500 known species of mammals have open relationships, so to speak."It's an uncommon arrangement," said lead author Nicholas Grebe, a postdoctoral associate in professor Christine Drea's lab at Duke University.Which raises a question: what makes some species biologically inclined to pair up for the long haul while others play the field?Studies over the last 30 years in rodents point to two hormones released during mating, oxytocin and vasopressin, suggesting that the key to lasting love may lie in differences in how they act on the brain.Some of the first clues came from influential research on prairie voles, small mouse-like mammals that, unlike most rodents, mate for life. When researchers compared the brains of monogamous prairie voles with their promiscuous counterparts, montane voles and meadow voles, they found that prairie voles had more "docking sites" for these hormones, particularly in parts of the brain's reward system.Since these "cuddle chemicals" were found to enhance male-female bonds in voles, researchers have long wondered if they might work the same way in humans.That's why the Duke-led team turned to lemurs. Despite being our most distant primate relatives, lemurs are a closer genetic match to humans than voles are.The researchers used an imaging technique called autoradiography to map binding sites for oxytocin and vasopressin in the brains of 12 lemurs that had died of natural causes at the Duke Lemur Center.The animals represented seven species: monogamous red-bellied and mongoose lemurs along with five promiscuous species in the same genus."They're really the only comparable natural experiment to look for biological signatures of monogamy in primates," Grebe said.Comparing the brain imaging results in lemurs with previous results in voles and monkeys revealed some noticeable differences in the density and distribution of hormone receptors. In other words, oxytocin and vasopressin appear to act on different parts of the brain in lemurs -- which means they may also have different effects, depending on their target cell's location.But within lemurs, the researchers were surprised to find few consistent differences between monogamous species and promiscuous ones."We don't see evidence of a pair-bond circuit" akin to that found in rodent brains, Grebe said.As a next step, the team is looking at how lemur couples behave toward each other if the actions of oxytocin are blocked, by feeding them an antagonist that temporarily prevents oxytocin from binding to its receptors in the brain.So what can lemurs teach us about love? The authors say their findings caution against drawing simple conclusions based on rodent experiments about how human social behaviors came to be.Oxytocin may be the "potion of devotion" for voles, but it may be the combined actions and interactions of multiple brain chemicals, along with ecological factors, that create long-lasting bonds in lemurs and other primates, including humans, Grebe said."There are probably a number of different ways through which monogamy is instantiated within the brain, and it depends on what animals we're looking at," Grebe said. "There's more going on than we originally thought."Other authors were: Annika Sharma at Duke, Sara Freeman at Utah State University, Michelle Palumbo at the California National Primate Research Center, Heather Patisaul at North Carolina State University, and Karen Bales at the University of California, Davis.This work was supported by grants from the National Science Foundation (SBE-1808803), the National Institute of Mental Health (NIMH R21MH115680), the Josiah Charles Trent Memorial Foundation Endowment Fund, the Charles Lafitte Foundation for Research, and Duke University.
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Animals
| 2,021 |
February 11, 2021
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https://www.sciencedaily.com/releases/2021/02/210211113943.htm
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Play and meaty food reduce hunting by cats
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Domestic cats hunt wildlife less if owners play with them daily and feed them a meat-rich food, new research shows.
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Hunting by cats is a conservation and welfare concern, but methods to reduce this are controversial and often rely on restricting cat behaviour in ways many owners find unacceptable.The new study -- by the University of Exeter -- found that introducing a premium commercial food where proteins came from meat reduced the number of prey animals cats brought home by 36%, and also that five to ten minutes of daily play with an owner resulted in a 25% reduction."Previous research in this area has focussed on inhibiting cats' ability to hunt, either by keeping them indoors or fitting them with collars, devices and deterrents," said Professor Robbie McDonald, of Exeter's Environment and Sustainability Institute."While keeping cats indoors is the only sure-fire way to prevent hunting, some owners are worried about the welfare implications of restricting their cat's outdoor access."Our study shows that -- using entirely non-invasive, non-restrictive methods -- owners can change what the cats themselves want to do."By playing with cats and changing their diets, owners can reduce their impact on wildlife without restricting their freedom."Play in the study involved owners simulating hunting by moving a feather toy on a string and wand so cats could stalk, chase and pounce. Owners also gave cats a toy mouse to play with after each "hunt," mimicking a real kill.It is not clear what elements of the meaty food led to the reduction in hunting."Some cat foods contain protein from plant sources such as soy, and it is possible that despite forming a 'complete diet' these foods leave some cats deficient in one or more micronutrients -prompting them to hunt," said Martina Cecchetti, the PhD student who conducted the experiments."However, meat production raises clear climate and environmental issues, so one of our next steps is to find out whether specific micronutrients could be added to cat foods to reduce hunting."We also plan to investigate whether different kinds of play have different effects, and whether combining strategies can reduce hunting even further."The study -- based on a 12-week trial of 355 cats in 219 households in south-west England -- also examined the effect of existing devices used to limit hunting by cats.Colourful "Birdsbesafe" collar covers reduced numbers of birds captured and brought home by 42%, but had no effect on hunting of mammals.Cat bells had no discernible overall effect -- although the researchers say the impact on individual cats varied widely, suggesting some cats learn to hunt successfully despite wearing a bell.Lisa George, from Helston in Cornwall, who looks after Minnie, a three-year-old tabby cat who took part in the trial, said: "Minnie loves to hunt. More often than not, she will bring her prey home and let it go in the house. We've had birds in the bedroom, rats in the waste paper bin (which took us three days to catch), rabbits in the utility room."On changing Minnie's food (previously supermarket own-brand), to Lily's Kitchen, I found she hardly hunted at all. This continued the whole time she was on this food. I can honestly say I couldn't believe the difference as regards her hunting behaviour."George Bradley, from project sponsors SongBird Survival, said: "This latest study we have funded is excellent news for birds."The data show that cat owners (like me) can make a few small and easy steps to really improve the health and happiness of our pets as well as make a really big difference for all our wildlife, especially our beloved songbirds."Making these easy-to-implement changes will be a win-win for birds, cats and cat owners."Dr Sarah Ellis, Head of Cat Advocacy at iCatCare, which is part of the advisory group for this research project, said: "We are really encouraged by the findings of this study."While many cat owners are wildlife lovers and find the killing and injuring of wild animals by their cats upsetting, many owners also feel that keeping their cats indoors or restricting their outdoor access would impact negatively on their cats' quality of life."At iCatCare, we are particularly excited about the positive effects of play -- this is an activity that owners can easily introduce at no or little cost, takes little time and is very cat-friendly."The mental and physical stimulation of predatory-like play are likely to help keep a cat in tip top condition and provide an appropriate behavioural outlet for its predatory behaviours."Dr Adam Grogan, Head of Wildlife at the RSPCA, welcomed the results of the study."The RSPCA cares for both cats and wild animals and we want to provide advice to cat owners that will benefit both cat and wild animal welfare," he said."This project provides us with alternatives for cat owners that are simple and effective and so easy to adopt."
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Animals
| 2,021 |
February 11, 2021
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https://www.sciencedaily.com/releases/2021/02/210211090123.htm
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Common pipistrelle bats attracted to wind turbines
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One of the most abundant bats in Europe may be attracted to wind turbines, a new study shows.
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The activity of common pipistrelle bats was monitored at 23 British wind farms and similar "control" locations close by without turbines.Activity was around a third higher at turbines than at control locations, and two thirds of occasions with high activity were recorded at turbines rather than the controls.The reasons for this are not clear. Possibilities include attraction to the turbines themselves, or the presence of more of the bats' insect prey around turbines."Either way it means the risk of fatality at wind turbines is increased, and probably explains the high fatalities of common pipistrelle bats seen at some wind farms across Europe," said Dr Suzanne Richardson.Common pipistrelle bats account for more than half of all bat fatalities at turbine sites in Europe."We know bats are killed by turbines worldwide, and reducing these fatalities is essential to ensuring a global increase in wind energy with minimal impact on bats," said Professor David Hosken, of the University of Exeter."To do that, we need to understand whether bats are actively attracted to, indifferent to, or repelled by, the turbines at large wind-energy installations."Our findings help explain why Environmental Impact Assessments conducted before the installation of turbines are poor predictors of actual fatality rates."Turbines are generally built in areas where bat activity is thought to be low, but this may not be an effective strategy if bats are attracted once turbines are built."Ongoing monitoring is required, and measures such as minimising blade rotation in periods of high collision risk are likely to be the most effective way to reduce fatalities."The study also monitored soprano pipistrelle bats, finding no conclusive evidence that this species is more active around turbines.Professor Fiona Mathews of the University of Sussex, who led the research, said: "Bat activity at wind farms is very variable."During periods of high wind speed, when most energy is generated, bat activity is low and so there is little risk to bats."In contrast, there can be high activity at turbines on nights with light winds and warm temperatures."Most of the attraction to turbines appears to be happening on these high activity nights."We have worked with the Statutory Nature Conservation Organisations and industry to produce guidance to help minimise the risks to bats."These include stopping blades rotating when no energy is being produced ('idling'). This is a win-win situation as little electricity generation is lost during these periods."The research was funded by the UK government's Department for Environment, Food and Rural Affairs (Defra), the Department of Energy and Climate Change, Natural England, Natural Resources Wales, Scottish Natural Heritage, RenewableUK and the Natural Environment Research Council (NERC).
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Animals
| 2,021 |
February 9, 2021
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https://www.sciencedaily.com/releases/2021/02/210209204123.htm
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Baby vampire bat adopted by mom's best friend
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During a study with captive vampire bats at the Smithsonian Tropical Research Institute (STRI) in Panama, a young vampire bat pup was adopted by an unrelated female after its mother died. Although this observation was not the first report of adoption in vampire bats, it is uniquely contextualized by more than 100 days of surveillance-camera footage. This footage captured by STRI research associate Gerry Carter's lab at Ohio State University reveals intimate details about the changing social relationships between the mother, the pup and the adoptive mother throughout their time in captivity.
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"The adoption took place after a very sad but ultimately serendipitous occurrence," said Imran Razik, then short-term fellow at STRI and doctoral student at the Ohio State University. "We realized after the mother died and the other female stepped in to adopt the baby, that we had recorded the entire social history of these two adult female bats who met for the first time in captivity. The strong relationship they formed based on grooming and sharing food with each other may have motivated this adoption."To learn more about how vampire bats form social bonds, researchers in Carter's lab captured vampire bats from three sites across Panama. These sites were all very distant from one another, such that bats from different sites were unrelated and had never met before. Their new home, a cage shrouded in black mesh fabric, was fitted with three infrared surveillance cameras that each recorded about six hours of footage every day for four months.Based on the footage, bats that were initially strangers began to form new social bonds, which are best defined by grooming and food-sharing interactions. Grooming other individuals is somewhat common, whereas food sharing is less common, especially among strangers.Vampire bats must eat often to survive -- typically every night. If a bat is unable to find a blood meal, it may receive regurgitated blood from a close social partner."To some extent, we were trying to see if we could influence partner choice between bats by manipulating if and when they could share food," Razik said. "We wanted to see how these grooming and food-sharing relationships were forming, so we kept track of all grooming and food-sharing interactions on the video recordings."When the mother bat, Lilith, unexpectedly died and her 19-day-old pup was adopted by another female, BD, the research team continued their observations."Shortly before Lilith died, I noticed that the pup would occasionally climb onto BD, and I suppose this may have initiated a cascade of neuroendocrine mechanisms that caused BD to start lactating," Razik said. BD was not pregnant and did not have a pup of her own, but Razik found that she was lactating on the day Lilith died. After Lilith's death, in addition to nursing, BD appeared to groom and share food with the pup more than any other female in the colony.A German researcher in the 1970s observed vampire bat adoptions several times in his captive colony, so this finding was not new. However, before leaving Panama, Razik gave a tour of the vampire bat project to one of STRI's emerita senior scientists, Mary Jane West-Eberhard, and she mentioned that it would be interesting to follow up on the relationships between the mother, the pup and the adopter. Carter and Rachel Page, STRI staff scientist and head of the Batlab in Gamboa, Panama, agreed that it was worth taking a closer look at the relationships between these bats.When Razik reviewed the videos after the experiment was finished, not only did it turn out that BD and Lilith had been primary grooming partners, but BD was also Lilith's top food donor. However, Lilith did not appear to share food with BD. Moreover, the data confirmed Razik's initial impression -- BD helped the pup at rates much higher than any other female."Another intriguing discovery was that BD and another bat, called BSCS, both of which had been in captivity before, were the two bats who groomed the pup the most," Razik said. "Now we're wondering if somehow the experience of being in captivity motivates individuals to invest in other bats at higher rates or adopt orphaned pups in critical need.""Compared to other bats, vampires make extraordinary investments in their offspring," Page said. "And we still don't know if, or how often, adoption may happen in the wild. But this was an amazing chance to better understand what kind of relationships might result in an adoption.""Studying adoption might give us insight into what immediate factors in the brain or environment affect parental-care decisions," Carter said. "As a new parent myself, I have come to realize the utter power of baby cuteness! I feel that my brain has been completely rewired. Most of us can understand the strong desire to adopt and care for a cute puppy or kitten, or to take on the ultimate responsibility of adopting a child. Regardless of why these traits exist, it is inherently fascinating to consider the neuroendocrine mechanisms that underlie them, the stimuli that trigger them, how they differ across species or individuals and how these traits might even be pre-adaptations for other forms of cooperation."This work was published in
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Animals
| 2,021 |
February 9, 2021
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https://www.sciencedaily.com/releases/2021/02/210209151837.htm
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Genetic evolution doesn't always take millions of years
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Love them or hate them, there's no doubt the European Starling is a wildly successful bird. A new study from the Cornell Lab of Ornithology examines this non-native species from the inside out. What exactly happened at the genetic level as the starling population exploded from just 80 birds released in New York City's Central Park in 1890, peaking at an estimated 200 million breeding adults spread all across North America? The study appears in the journal
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"The amazing thing about the evolutionary changes among starling populations since they were introduced in North America is that the changes happened in a span of just 130 years in parallel with a huge expansion in the bird's range and population size," says lead author Natalie Hofmeister, a doctoral candidate at the Cornell Lab. "For a long time we didn't think that was possible -- that it took millions of years for genetic mutations to change a genome."The genetic differences found among North American starlings are very subtle. In fact, after researchers sequenced the genomes of birds from widely distributed locations around the United States, the genomes were all remarkably alike -- any starling could undoubtedly mate successfully with another, no matter where they're originally from. But the researchers did find the genetic signatures of change in areas of the genome that control how starlings adapt to variations in temperature and rainfall. Study authors concluded the birds had undergone "rapid local adaptation," adjusting to conditions not found in their native European range.Another key factor is movement. The study points out that there's a lot of movement among starlings. All that movement means starlings kept establishing new populations as they spread westward, and each population had to adapt to new environments. The adaptation may not have resulted from a new mutation but from an existing genetic variation in the founding population."A genetic variation that might not have been useful in one environment could turn out to be very beneficial in another," Hofmeister explains. "So, a variation related to temperature and rainfall that enhanced survival became more common in a new environment." The massive size of the total starling population across North America meant these gene variants could be passed along across the generations.European Starlings in North America are unusual in another way. Species with a highly restricted gene pool -- a genetic bottleneck -- are more likely to become extinct because of fertility issues associated with in-breeding, a problem that endangered animals also face. The introduction of just 80 birds in Central Park (released in an attempt to introduce all the birds mentioned in Shakespeare's plays to North America) was one of many attempted introductions in other parts of the country. It's possible the resulting gene flow among these populations prevented the species from dying out. It's an area of speculation ripe for further study."What I think is really cool is that the starlings in North America appear to have adapted to different conditions across the range," Hofmeister says. "So, it wasn't just that they reproduced really quickly, and then just kept reproducing. It's that they specialized once they arrived in new areas."Despite their success and large numbers, the European Starling is now in steep decline, like so many other species in North America. The current population is half the size it was 50 years ago -- down from an estimated 166.2 million breeding birds in 1970 to 85.1 million (Rosenberg et. al. Science 2019) . The species is also declining in Europe.Though starlings are reviled for some of their less admirable habits and their impact on native species, Hofmeister says they're fascinating birds and really quite beautiful. And they're allowing scientists to follow one of the many threads that influence avian evolution.
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Animals
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February 9, 2021
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https://www.sciencedaily.com/releases/2021/02/210209151819.htm
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Researchers uncover hidden hunting tactics of wolves in Minnesota's Northwoods
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Wolves are arguably the most well-studied large predators in the world, yet new research shows there is still a lot to learn about their hunting tactics. Typically, wolves hunt large mammals like moose, deer, and bison in packs by outrunning, outlasting, and exhausting their prey. However, throughout the dense boreal forests in North America and Eurasia, during the summer wolves often hunt beavers by themselves.
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But how does a wolf catch a semi-aquatic prey that spends little time on land and never ventures far from the safety of its pond? Turns out with patience, and a lot of waiting.In a new paper published in the journal "Over a five-year period, we estimate that our field research team collectively put in over 15,000 person-hours to search nearly 12,000 locations where wolves had spent time. Through this effort, we ended up documenting 748 locations where wolves waited to ambush beavers but were unsuccessful, and 214 instances where wolves killed beavers," said Sean Johnson-Bice, a co-author of the study. "This dedicated fieldwork has provided unprecedented insight into the hunting tactics wolves use in boreal environments."Beavers have extremely poor eyesight, so they rely primarily on their well-developed sense of smell to detect predators on land -- and wolves appear to have learned this through time. Researchers discovered wolves choose ambushing sites within a few feet of where beavers are active on land because wolves have learned beavers cannot visually detect them. When doing so, wolves almost always choose ambushing sites that are downwind to avoid being smelled by beavers."The results are very clear," said Tom Gable, the study's lead-author: "89-94% of the ambushing sites were downwind, where beavers were likely unable to smell wolves."When staking out beavers, wolves appear to be surprisingly patient. They spend substantial periods of time waiting next to areas where beavers are active on land, such as near beaver dams and trails."Wolves waited an average of four hours during each stakeout. But they often waited eight-12 hours or more, and one wolf even waited-in-ambush for 30 hours," said study co-author Austin Homkes.The researchers note that these behaviors were not unique to a few wolves. Instead, wolves from multiple packs across several years used the same ambushing tactics, indicating that this behavior is widespread throughout the Greater Voyageurs Ecosystem and likely other ecosystems where wolves hunt beavers. Notably, wolves and beavers co-occur across much of the Northern Hemisphere so the implications have wide applicability."Gathering data to demonstrate how wind direction influences the ambushing behavior of predators has been difficult for animal ecologists," said co-author Joseph Bump. "Scientists have long-thought that ambush predators are able to strategically choose ambush sites in areas where prey are unable to detect them via scent. Until now though, documenting these hunting tactics in exhaustive detail proved extremely challenging."Ultimately, the study challenges the classic concept that wolves are solely cursorial predators (i.e., predators that kill their prey by outrunning and outlasting them). Instead, wolf-hunting strategies appear highly flexible, and they are able to switch between hunting modes (cursorial and ambush hunting) depending on their prey."It is the first systematic analysis of wolf ambushing behavior," said Gable. "It overturns the traditional notion that wolves rely solely on hunting strategies that involve pursuing, testing, and running down prey."
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Animals
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February 9, 2021
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https://www.sciencedaily.com/releases/2021/02/210209113831.htm
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Challenges of animal ownership during the pandemic should be considered alongside the potential benefits, study shows
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Animal owners frequently report concerns and worries relating to caring for their animal during the pandemic, new research suggests.
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The study, by the University of York, also revealed owners had increased their appreciation of their animals during the first lockdown phase. The notion that people "could not live without" their animals and that they were a "godsend" or a "lifeline" in the pandemic was frequently expressed.The study has been investigating the role of animals as sources of emotional and physical support during the pandemic. More than 40 per cent of UK households are estimated to own at least one animal.There was consensus among participants that companion animals constituted a reliable source of support, providing unconditional love, affection and companionship. Animals were frequently perceived as being able to enhance mood, reduce stress, and help people to cope generally with the COVID-19 lockdown phase. However, the study also showed that animal ownership may result in significant concerns that might have outweighed the benefits in some cases.Dr Elena Ratschen from the Department of Health Sciences said: "The findings complement and extend previous insights into the impact of human-animal interaction with both companion and non-companion animals."Dr Emily Shoesmith also from the Department of Health Sciences added: "What was interesting was many owners perceived their animal as helping them cope with the first lockdown phase, offering an important source of emotional support. However, concerns and worries relating to caring for their animal during this time were frequently reported and were likely to have exacerbated feelings of stress for the owner."Nearly 6,000 people across the UK took part in the research which asked participants a series of questions during the first lockdown, including outcomes related to mental health, wellbeing and loneliness; the human-animal bond and human-animal interactions.The final item of the survey invited free-text responses, allowing participants to describe any experiences of their human-animal relationships during the first lockdown phase. Four main themes were identified, including: the positive impact of animal ownership during the Covid-19 lockdown phase, concerns relating to animal ownership, grief and loss of an animal during the Covid-19 lockdown, and the impact of engaging with non-companion animals.Some participants said that their animals helped them cope with mental health conditions. One respondent said her dog helped "keep my anxiety levels down by talking to her when I'm out and breaking my focus on anything negative. I am terrified of catching COVID-19 but having the dog keeps me mentally and physically better in the current environment."Another respondent described how different animal species provided emotional support in different ways: "All my animals have helped keep me motivated, calm and happy during this time, not just the one I am closest to. Different species have different qualities: the dog is a close companion, but reptiles are interesting and calming to watch and guinea pigs are entertaining. General pet care tasks give purpose and structure to my day."Other people reported that their animals were able to provide unique emotional support as a result of their ability to respond to their owners in an intuitive manner, especially in times of distress. One participant said: "My whippet has really picked up on this, he stays by my side constantly and feeds and mirrors my emotions. He is hyper vigilant to my needs giving lots of attention and affection."Many participants also commented that animal ownership encouraged and promoted physical activity, especially for owners of dogs and horses. One respondent said "My dogs means I go out every day for exercise. Without them, I don't think I'd go out at all during this time."However, a number of participants expressed that despite the bond with their animal, this was not a replacement for human social contact, that had been considerably restricted during the lockdown phase. One person said: "My dogs and cats are not a replacement for human contact, which I am sorely missing. But they have been a welcome distraction and have given me something to focus on and stopped me from feeling so lonely."Negative aspects to animal ownership during lockdown were also described by a number of participants. Owners expressed they were often worried or concerned about various elements of ownership, including the possibility of animals carrying the Covid-19 virus, access to veterinary care, caring for their animals, and concerns about their animal experiencing separation-related problems upon their return to work. It was apparent that these concerns often exacerbated stress in participants due to the responsibilities and potential additional financial cost of animal ownership.Arranging alternative care for an animal whilst the owner was working outside of the home was often cited as a concern of animal ownership. Many people, primarily dog owners, noted that animal care that was readily available prior to lockdown had since been restricted, and this had resulted in feelings of anxiety. Some participants suggested that it would be beneficial for animal care to be easily accessible for key workers in the context of increased working hours.Due to financial uncertainty, participants expressed their concern over buying pet food and other necessities or worried about being able to provide healthcare if required and maintaining their animal's insurance. One respondent said "I worry for their health and wellbeing during these times, with the concern over financial difficulties if work becomes scarcer. They are important members of our family."There was also a general sense that interactions with wildlife and frequent contact with nature had a positive impact on mental health. Some participants suggested that seeing an animal in their natural environment provided opportunities for distraction from their inner feelings of distress due to the pandemic.
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Animals
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February 8, 2021
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https://www.sciencedaily.com/releases/2021/02/210208104615.htm
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Marmoset monkeys have personalities too
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In humans, differences in personalities have been evident since the ancient times. Personality in animals has long been ignored, but recently this question has received increasing research interest as it has been realized that personality has evolutionary and ecological significance. An international team of behavioral biologists from Austria, Brazil and the Netherlands, with Vedrana Å lipogor from the University of Vienna as leading author of the study, designed a set of tasks to assess personality of common marmosets. These results have just been published in
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Marmosets are small highly social New World monkeys that parallel humans in their social organization, as they live in cohesive family units, where parents act as breeders and their offspring help them raise the young. The researchers showed that captive monkeys living in Austria as well as those monkeys living under natural conditions in semi-arid Caatinga forests of Northeastern Brazil show consistent differences in their personalities, similarly to humans.In the personality tasks, the monkeys could explore and engage with a familiar environment, new foods, new objects, and situations mimicking a predatory situation (e.g. encountering a plastic toy snake or a strange-looking object). The researchers carefully observed these monkeys' reactions in the tasks, for instance when trying a piece of jackfruit or engaging with a colorful rattle shaped toy. Some individuals were fast to approach any novelty, while others were more careful; hereby showing a similar pattern to humans: for instance, some humans enjoy trying out new restaurants, whereas others prefer to eat in their favorite restaurant. What is more interesting, when comparing personality traits of monkeys in Austria across four years, the authors found that these monkeys are quite consistent in their personality traits (e.g., those that are explorative when they are younger, stay similarly explorative four years afterwards). The only exception to this rule were monkeys who changed their breeding status in the family units."We have found that those monkeys who became breeders, that is, dominant individuals in the group, also became bolder," says Vedrana Šlipogor, a postdoctoral fellow at the University of Vienna. "In humans and other non-human animals we see a similar pattern. People effective in leading positions often show higher levels of extraversion, as well as some other traits (e.g., high agreeableness and conscientiousness and low neuroticism). In homing pigeons, it has been shown that bolder individuals have a higher rank in the hierarchy and are likely to influence direction of collective movement, and subordinate field crickets who change their status to dominant, also show an increase in boldness, exploration and activity."It is especially interesting that this is the first time that researchers captured personality in wild marmoset monkeys. "We adapted our test battery from the well-controlled captive setting to the unpredictable conditions in the wild. In the wild, monkeys have plenty of things to do in their day-to-day lives, however, and in exchange for some bananas, they decided to participate in these tasks. We were pleased to discover that wild monkeys show a very similar personality structure as those in captivity," says Thomas Bugnyar, Professor of Cognitive Ethology at the University of Vienna and senior author of the study. "This gives further support that consistent variation in individuals can be reliably assessed with our personality test battery, both in captive and wild settings. It also gives us more confidence that we provide the best possible conditions to our monkeys in Austria, as they show such striking similarity to the marmosets in Brazil."
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Animals
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February 5, 2021
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https://www.sciencedaily.com/releases/2021/02/210205121245.htm
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Pangolin coronavirus could jump to humans, research suggests
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Scientists at the Francis Crick Institute have found important structural similarities between SARS-CoV-2 and a pangolin coronavirus, suggesting that a pangolin coronavirus could infect humans.
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While SARS-CoV-2 is thought to have evolved from a bat coronavirus, its exact evolutionary path is still a mystery. Uncovering its history is challenging as there are likely many undiscovered bat coronaviruses and, due to differences between bat coronaviruses and SARS-CoV-2, it is thought that the virus may have passed to humans via at least one other species.In their study, published in Antoni Wrobel, co-lead author and postdoctoral training fellow in the Structural Biology of Disease Processes Laboratory at the Crick, says: "By testing if the spike protein of a given virus can bind with cell receptors from different species, we're able to see if, in theory, the virus could infect this species.""Importantly here, we've shown two key things. Firstly, that this bat virus would unlikely be able to infect pangolins. And secondly that a pangolin virus could potentially infect humans."The team used cryo-electron microscopy to uncover in minute detail the structure of the pangolin coronavirus' spike protein, which is responsible for binding to and infecting cells. While some parts of the pangolin virus' spike were found to be incredibly similar to SARS-CoV-2, other areas differed.In terms of understanding the evolutionary path of SARS-CoV-2, this work does not confirm whether or not this pangolin virus is definitely part of the chain of evolution for SARS-CoV-2. But the findings do support various possible scenarios for how the coronavirus jumped from bats to humans. One potential route is that SARS-CoV-2 originated from a different, currently unknown bat coronavirus which could infect pangolins, and from this species it then moved to humans. Or alternatively, RaTG13 or a similar bat coronavirus might have merged with another coronavirus in a different intermediate species, other than a pangolin.Donald Benton, co-lead author and postdoctoral training fellow in the Structural Biology of Disease Processes Laboratory at the Crick, says: "We still don't have evidence to confirm the evolutionary path of SARS-CoV-2 or to prove definitively that this virus did pass through pangolins to humans.""However, we have shown that a pangolin virus could potentially jump to humans, so we urge caution in any contact with this species and the end of illegal smuggling and trade in pangolins to protect against this risk."Steve Gamblin, group leader of the Structural Biology of Disease Processes Laboratory at the Crick says: "A lot is still to be uncovered about the evolution of SARS-CoV-2, but the more we know about its history and which species it passed through, the more we understand about how it works, and how it may continue to evolve."This work builds upon previous studies from the Crick team, including research published in July 2020, which found that the bat coronavirus RaTG13 could not effectively bind to human receptors.The team are continuing to examine the spikes of SARS-CoV-2 and related coronaviruses, including other bat viruses, to better understand the mechanisms of infection and evolution.
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Animals
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February 5, 2021
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https://www.sciencedaily.com/releases/2021/02/210205104233.htm
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Birds living in natural habits can help inform captive care
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Bird species that live in their natural habitats can help zoos learn how to manage those in captivity, according to a new review.
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Birds are the most diverse group housed by zoos around the world, but zoo-based research tends not to focus on birds.A new article published in the journal Likewise, birds living under the care of humans can also help guide and develop conservation action for those living in the wild."Research into wild birds is extremely useful for furthering how birds are managed in zoos," said Dr Rose."For species of conservation concern, zoo professionals can be linked with field biologists to share information on how to best care for these species in captivity and how to develop and formulate conservation actions."We can use proxy species -- those common in zoos -- to develop practices for conservation that can be used for less familiar species that might be of concern and need help from information gathered through things such as captive breeding."Or we can promote the threats that these not-in-the-zoo species face by using the commoner species as an ambassador."We do this through my work at the Wildfowl & Wetlands Trust, promoting the rarer species of flamingo that are in the wild using the commoner ones we keep in the living collection."In the review, Dr Rose uses hornbills as an example, a species of bird that is essential to the long viability and sustainability of biodiversity in the rainforest.The helmeted hornbill, a critically endangered species, plays an important role in the dispersal of seeds within pristine, undistributed areas of south-east Asian rainforests.The population decline of the helmeted hornbill has been caused by poaching of the birds for their "ivory," the large casque on the bird's head and bill that can be up to 10% of its overall body mass.Whilst the helmeted hornbill is not found in captivity, other species of large hornbill are.By looking at the ecological role of the helmeted hornbill in its natural habitat, zoos have been able to design enclosures that will increase chances of reproduction.For example, by identifying the temperature and humidity range of hornbill nesting sites in the wild which are more likely to hatch eggs, zoos have been able to use this data to enable them to match these environmental conditions as closely as possible.A similar situation happened with the Guam kingfishers, a species that is extinct in the wild and reliant on captive breeding for its survival.Data from the nesting locations of the closely related Pohnpei kingfisher, found on a neighbouring island, showed that temperatures were hotter than those sometimes provided for captive Guam kingfishers.The findings led to zoos raising the temperature to improve nesting success amongst the species.Zoos have also been able to guide conservation action for hornbills living in the wild by monitoring the behaviour of these birds and discovering that using nest boxes enhances the quality of habitats for hornbills to breed in, which has led to these boxes being built in areas of the helmeted hornbill's range in Borneo.Expertise and financial support has been provided by several large zoological collections in European Association of Zoos and Aquaria (EAZA) and North American Association of Zoos and Aquariums (AZA) that has successfully seen wild rhinoceros hornbills, listed as vulnerable, fledge a chick from an artificial nest box in the Bornean rainforest."The effect of visitors on zoos can also help direct future research questions and increase understanding of birds under human care," adds Dr Rose."Developing zoo bird exhibits to theme them around specific conservation messages can be used to promote wider understanding of the threats faced by wild birds specifically and hopefully encourage human behaviour change that benefits ecosystem health."
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Animals
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February 5, 2021
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https://www.sciencedaily.com/releases/2021/02/210205210627.htm
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We're more like primitive fishes than once believed, new research shows
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People traditionally think that lungs and limbs are key innovations that came with the vertebrate transition from water to land. But in fact, the genetic basis of air-breathing and limb movement was already established in our fish ancestor 50 million years earlier. This, according to a recent genome mapping of primitive fish conducted by the University of Copenhagen, among others. The new study changes our understanding of a key milestone in our own evolutionary history.
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There is nothing new about humans and all other vertebrates having evolved from fish. The conventional understanding has been that certain fish shimmied landwards roughly 370 million years ago as primitive, lizard-like animals known as tetrapods. According to this understanding, our fish ancestors came out from water to land by converting their fins to limbs and breathing under water to air-breathing.However, limbs and lungs are not innovations that appeared as recent as once believed. Our common fish ancestor that lived 50 million years before the tetrapod first came ashore already carried the genetic codes for limb-like forms and air breathing needed for landing. These genetic codes are still present in humans and a group of primitive fishes.This has been demonstrated by recent genomic research conducted by University of Copenhagen and their partners. The new research reports that the evolution of these ancestral genetic codes might have contributed to the vertebrate water-to-land transition, which changes the traditional view of the sequence and timeline of this big evolutionary jump. The study has been published in the scientific journal "The water-to-land transition is a major milestone in our evolutionary history. The key to understanding how this transition happened is to reveal when and how the lungs and limbs evolved. We are now able to demonstrate that the genetic basis underlying these biological functions occurred much earlier before the first animals came ashore," stated by professor and lead author Guojie Zhang, from Villum Centre for Biodiversity Genomics, at the University of Copenhagen's Department of Biology.A group of ancient living fishes might hold the key to explain how the tetrapod ultimately could grow limbs and breathe on air. The group of fishes includes the bichir that lives in shallow freshwater habitats in Africa. These fishes differ from most other extant bony fishes by carrying traits that our early fish ancestors might have had over 420 million years ago. And the same traits are also present in for example humans. Through a genomic sequencing the researchers found that the genes needed for the development of lungs and limbs have already appeared in these primitive species.Using pectoral fins with a locomotor function like limbs, the bichir can move about on land in a similar way to the tetrapod. Researchers have for some years believed that pectoral fins in bichir represent the fins that our early fish ancestors had.The new genome mapping shows that the joint which connects the socalled metapterygium bone with the radial bones in the pectoral fin in the bichir is homologous to synovial joints in humans -- the joints that connect upper arm and forearm bones. The DNA sequence that controls the formation of our synovial joints already existed in the common ancestors of bonefish and is still present in these primitive fishes and in terrestrial vertebrates. At some point, this DNA sequence and the synovial joint was lost in all of the common bony fishes -- the socalled teleosts."This genetic code and the joint allows our bones move freely, which explains why the bichir can move around on land," says Guojie Zhang.Moreover, the bichir and a few other primitive fishes have a pair of lungs that anatomically resembles ours. The new study reveals that the lungs in both bichir and alligator gar also function in a similar manner and express same set of genes as human lungs.At the same time, the study demonstrates that the tissue of the lung and swim bladder of most extant fishes are very similar in gene expression, confirming they are homologous organs as predicted by Darwin. But while Darwin suggested that swim bladders converted to lungs, the study suggests it is more likely that swim bladders evolved from lungs. The research suggests that our early bony fish ancestors had primitive functional lungs. Through evolution, one branch of fish preserved the lung functions that are more adapted to air breathing and ultimately led to the evolution of tetrapods. The other branch of fishes modified the lung structure and evolved with swim bladders, leading the evolution of teleosts. The swim bladders allow these fishes to maintain buoyancy and perceive pressure, thus better survive under water."The study enlightens us with regards to where our body organs came from and how their functions are decoded in the genome. Thus, some of the functions related to lung and limbs did not evolve at the time when the water-to-land transition occurred, but are encoded by some ancient gene regulatory mechanisms that were already present in our fish ancestor far before landing. It is interesting that these genetic codes are still present in these 'living-fossil'' fishes, which offer us the opportunity to trace back the root of these genes," concludes Guojie Zhang.Primitive fish and humans also share a common and critical function in the cardio-respiratory system: The conus arteriosus, a structure in the right ventricle of our heart which might allow the heart to efficiently deliver the oxygen to the whole body, and which is also found in the bichir. However, the vast majority of bony fish have lost this structure. The researchers discovered a genetic element that appears to control the development of the conus arteriosus. Transgenic experiments with mice showed that when researchers removed this genetic element, the mutated mice died due to thinner, smaller right ventricles, which lead to congenital heart defects and compromised heart function.
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204143950.htm
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Fossil pigments shed new light on vertebrate evolution
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UCC palaeontologists have discovered new evidence that the fate of vertebrate animals over the last 400 million years has been shaped by microscopic melanin pigments.
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This new twist in the story of animal evolution is based on cutting-edge analyses of melanin granules -- melanosomes -- in many different fossil and modern vertebrates, including fish, amphibians, reptiles, birds and mammals. Melanin and melanosomes have traditionally been linked to outermost body tissues such as skin, hair and feathers, with important roles in UV protection and stiffening of tissues. Analyses of where different animals store melanin in the body, however, show that different vertebrate groups concentrate melanin in different organs, revealing shifts in how animals have used melanin over the last 400 million years.The study, published today in the journal "Most studies of fossil melanin have focussed on melanin in fossil feathers and skin, and what colours ancient animals had," said study leader Prof. McNamara. "By comparing melanin in different animals -- how much melanin they have, where in the body it occurs, what melanin type and composition is present -- and by studying fossils, we discovered new evidence for changes in the functions of melanin through deep time."The research shows that amphibians and reptiles concentrate melanin in internal organs, where it supports the immune system and stores metals. In birds and mammals, however, almost all melanin occurs in hair and feathers. This difference has an unexpected source -- evolution of the immune system and of warm-blooded lifestyles."There are pros and cons to having melanin in the body," said team member Dr Rossi. "Melanin is hugely beneficial, but it also generates free radicals, which are harmful. This creates a major problem for animals."During the evolution of hair and feathers, mammals and birds evolved more sophisticated immune systems than in amphibians and reptiles. This meant that large amounts of melanin were no longer necessary in internal organs. Melanin storage then shifted to hair and feathers, which are dead tissues, thereby removing harmful metals and free radicals from living body parts."Melanin is a two-sided coin," said Prof. McNamara. "It's useful, but toxic. Birds and mammals basically came up with an ingenious solution during the early Triassic -- pump melanin into new, outer, dead skin tissues that were evolving at the time. This set the scene for the evolution of the incredible diversity of plumage and fur patterning which we see today."The study also shows that key genes can be mapped onto colour patterns in fossils, tracking the genetic evolution of melanin through time, and that animals preferentially use less toxic forms of melanin. "There's still a lot about melanin genetics and physiology that we don't understand," said Dr Ducrest of Lausanne University. What's clear, however, is that the fossil record is a valuable source of information that we can use going forwards."
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204143209.htm
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DNA-based technique allows researchers to determine age of living beluga whales in Alaska
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Researchers can now determine the age and sex of living beluga whales in Alaska's Cook Inlet thanks to a new DNA-based technique that uses information from small samples of skin tissue.
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Accurate age estimates are vital to conservation efforts for Cook Inlet belugas, which were listed as endangered following a significant population decline in the 1990s. Previously, researchers could only determine the age of beluga whales by studying the teeth of dead animals.The new aging method uses DNA methylation data and machine learning to develop a model that captures the relationship between methylation and age. This relationship provides an epigenetic clock for beluga whales.Epigenetics broadly refers to non-heritable molecular modifications of DNA that change the way genes function. Methylation is one form of epigenetics; it is a biological process by which methyl groups are added to the DNA molecule. In mammals, there are places along the genome that become more methylated as an animal ages.The new method for determining Cook Inlet beluga whales' age represents a significant advance in understanding the life history of the species and will have applications to other whale species. The method also can be used to identify an animal's sex."The development of this tool and the use of the epigenetic clock is a major advance in the science of aging," said Eleanor Bors, the study's lead author. Bors worked on the project as a post-doctoral fellow at Oregon State University's Marine Mammal Institute. "We have the technology now to do this easily and it can become a routine part of research on beluga whales."The researchers' findings were just published in the journal Beluga whales are known for their distinctive white color and rounded heads. They average 13 feet in length and 3,150 pounds, and have a lifespan of up to 80 years. They are found in Alaska and throughout the Arctic.Cook Inlet beluga whales are a geographically and genetically distinct population that does not migrate. The population had numbered more than 1,000 in 1979 but declined sharply from 653 to 347 between 1994 and 1998, in part due to unregulated hunting.Hunting regulations were implemented in 2000 but the population has not rebounded. Today there are an estimated 279 beluga whales in the population, and they have been designated one of NOAA's "Species in the Spotlight," an initiative to bring greater attention and resources to species most highly at risk of extinction.A NOAA species recovery plan issued in 2016 highlighted the need to determine the age structure of the Cook Inlet beluga population to better understand growth, reproduction and survival rates.In toothed whales and dolphins, age is typically determined by examining teeth, which record age in growth layers similar to tree rings. But that option is only available once an animal has died. Using genomic information, which can be collected with a small biopsy dart, is an important development in the study of living whales and dolphins.Researchers were able to develop the DNA methylation technique in part because the beluga whale's genome had already been sequenced, Baker said.Working with tissue samples from 67 dead whales, the researchers measured methylation levels across tens of thousands of sites in the genome and determined that an effective clock model could be built using just 23 sites related to aging.The researchers used machine learning to develop an epigenetic age profile for the species based on their findings. Finally, researchers calibrated their findings against age information determined by teeth recovered from the same animals."With all of that information, we were able to accurately model the relationship between methylation and age," Bors said.Once the profile was built, researchers analyzed skin samples collected between 2016 and 2018 from 38 living whales. They were able to estimate ages and identify the sex of the animals using DNA methylation.The new aging method gives researchers an important piece of data to use in their work to understand and, they hope, identify ways to reverse the population decline, Wade said. For example, while belugas in other populations reach sexual maturity at about age 8 or 9, the researchers have found that among the Cook Inlet whales tested so far, just one between ages 10 and 19 was pregnant."If reproduction is substantially delayed like that, it's a signal that is surprising. That is an area we can explore further," said Wade. "We want to keep adding data to see what else we can learn. We see this aging technique as something we want to do routinely now."As additional samples are collected, the age profile for the species should continue to calibrate and refine itself, Baker added.One question for future research is whether this process for determining age is applicable to other beluga whale populations, or more broadly to other whales, dolphins and porpoises, the researchers said. Genetic information collected in the database also can be mined for other biological changes."There is a lot of interest in methylation as an indicator of stress, for example," Baker said. "I'm also interested in kinship relationships within the population, which will now be easier to determine by knowing the age of individuals."The research was supported by a grant from the North Pacific Research Board and the Paul G. Allen Frontiers Group.
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204131438.htm
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How elephants evolved to become big and cancer-resistant
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All things being equal, large, long-lived animals should have the highest risk of cancer.
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The calculation is simple: Tumors grow when genetic mutations cause individual cells to reproduce too quickly. A long life creates more opportunities for those cancerous mutations to arise. So, too, does a massive body: Big creatures -- which have many more cells -- should develop tumors more frequently.Why, then, does cancer rarely afflict elephants, with their long lifespans and gargantuan bodies? They are some of the world's largest land animals.A new study delves into this sizeable mystery, showing that elephants possess extra copies of a wide variety of genes associated with tumor suppression.But this phenomenon is not unique to elephants, scientists say: The research concluded that duplication of tumor suppressor genes is quite common among elephants' living and extinct relatives, including in small ones like Cape golden moles (a burrowing animal) and elephant shrews (a long-nosed insectivore). The data suggest that tumor suppression capabilities preceded or coincided with the evolution of exceptionally big bodies, facilitating this development.The study was published on Jan. 29 in the journal "One of the expectations is that as you get a really big body, your burden of cancer should increase because things with big bodies have more cells," says Lynch, PhD, assistant professor in the Department of Biological Sciences in the UB College of Arts and Sciences. "The fact that this isn't true across species -- a long-standing paradox in evolutionary medicine and cancer biology -- indicates that evolution found a way to reduce cancer risk."In the new study, "We explored how elephants and their living and extinct relatives evolved to be cancer-resistant," Lynch says. "We have past research looking at TP53, a well-known tumor suppressor. This time, we said, 'Let's just look at whether the entire elephant genome includes more copies of tumor suppressors than what you'd expect.' Is the trend general? Or is the trend specific to one gene? We found that it was general: Elephants have lots and lots and lots of extra copies of tumor suppressor genes, and they all contribute probably a little bit to cancer resistance."Though many elephant relatives harbor extra copies of tumor suppressor genes, the scientists found that elephant genomes possess some unique duplications that may contribute to tumor suppression through genes involved in DNA repair; resistance to oxidative stress; and cellular growth, aging and death."By determining how big, long-lived species evolved better ways to suppress cancer, we can learn something new about how evolution works and hopefully find ways to use that knowledge to inspire new cancer treatments," says Vazquez, PhD, a postdoctoral researcher at UC Berkeley who completed much of the project while earning his PhD at the University of Chicago.Elephants are a great case study for understanding the evolution of cancer protection because they belong to a group of mammals -- the Afrotherians -- that are mostly small-bodied.The study searched for extra copies of tumor suppressor genes in the DNA of Asian, African savanna and African forest elephants, as well as in the genomes of a number of fellow Afrotherians, such as Cape golden moles, elephant shrews, rock hyraxes, manatees, extinct woolly mammoths, extinct mastodons and more. The team also studied certain species belonging to a group of mammals called Xenarthra that is closely related to Afrotherians, and found some extra copies of tumor suppressors in those animals' genomes as well.Given the findings, Lynch wonders whether the duplication of tumor suppressors may have aided the evolution of other ancient large bodies within these groups."If you pick a weird mammal, there's a good chance that it will be in these groups, the Afrotherians and Xenarthrans: armadillos, aardvarks, sloths, anteaters, all of these weird mammals," Lynch says. "We found that within these groups of organisms, the ones we studied all seem to have extra copies of tumor suppressor genes. That may be why in the last Ice Age, there were giant sloths and ancient mega-armadillos. There's even an extinct species of manatee relative called the Steller's sea cow that was elephant-big. Extra copies of tumor suppressors may have helped all of these animals get really, really big."
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204131410.htm
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Horse remains reveal new insights into how Native peoples raised horses
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A new analysis of a horse previously believed to be from the Ice Age shows that the animal actually died just a few hundred years ago -- and was raised, ridden and cared for by Native peoples. The study sheds light on the early relationships between horses and their guardians in the Americas.
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The findings, published today in the journal In 2018, a Utah couple was doing landscaping in their backyard near the city of Provo when they unearthed something surprising: an almost complete skeleton of a horse about the size of a Shetland pony. Scientists and the media took note. Preliminary data suggested that the horse might be more than 10,000 years old."It was found in the ground in these geologic deposits from the Pleistocene -- the last Ice Age," said William Taylor, lead author of the new research and a curator of archaeology at the CU Museum of Natural History at the University of Colorado Boulder.Based on a detailed study of the horse's bones and DNA, however, Taylor and his colleagues concluded that it wasn't an Ice Age mammal at all. Instead, the animal was a domesticated horse that had likely belonged to Ute or Shoshone communities before Europeans had a permanent presence in the region.But Taylor is far from disappointed. He said the animal reveals valuable information about how Indigenous groups in the West looked after their horses."This study demonstrates a very sophisticated relationship between Indigenous peoples and horses," said Taylor, also an assistant professor in the Department of Anthropology. "It also tells us that there might be a lot more important clues to the human-horse story contained in the horse bones that are out there in libraries and museum collections."Taylor leads an effort funded by the U.S. National Science Foundation, called "Horses and Human Societies in the American West." And he's something akin to a forensic scientist -- except he studies the remains of ancient animals, from horses to reindeer. He said that researchers can learn a lot by collecting the clues hidden in bones."The skeleton that you or I have is a chronicle of what we've done in our lives," Taylor said. "If I were to keel over right now, and you looked at my skeleton, you'd see that I was right-handed or that I spend most of my hours at a computer."When Taylor first laid eyes on the Lehi horse in 2018, he was immediately skeptical that it was an Ice Age fossil. Ancient horses first evolved in North America and were common during the Pleistocene, he said, going extinct at about the same time as many other large mammals like mammoths. This horse, however, showed characteristic fractures in the vertebrae along its back."That was an eyebrow raiser," Taylor said.He explained that such fractures often occur when a human body bangs repeatedly into a horse's spine during riding -- they rarely show up in wild animals, and are often most pronounced in horses ridden without a frame saddle. So he and his colleagues decided to dig deeper.DNA analyses by coauthors at the University of Toulouse in France revealed that the Lehi horse was a roughly 12-year-old female belonging to the species Equus caballus (today's domestic horse). Radiocarbon dating showed that it had died sometime after the late 17th century. The horse also seemed to be suffering from arthritis in several of its limbs."The life of a domestic horse can be a hard one, and it leaves a lot of impacts on the skeleton," Taylor said.He added that scientists originally believed that the horse was so ancient in part because of its location deep in the sands along the edge of Utah Lake: Its caretakers appear to have dug a hole and intentionally buried the animal after it died, making it look initially as if it had come from Ice Age sediments.And despite the animal's injuries, which would have probably made the Lehi horse lame, people had continued to care for the mare -- possibly because they were breeding her with stallions in their herd.For Carlton Shield Chief Gover, a coauthor of the new study, the research is another example of the buried history of Indigenous groups and horses.He explained that most researchers have tended to view this relationship through a European lens: Spaniards brought the animals to the Americas on boats, and white settlers shaped how Native peoples interacted with them.But that view glosses over just how uniquely Indigenous the horse became in the Americas after those first introductions."There was a lot going on that Europeans didn't see," said Shield Chief Gover, a graduate student at CU Boulder and a tribal citizen of the Pawnee Nation. "There was a 200-year period where populations in the Great Plains and the West were adapting their cultures to the horse."For many Plains groups, horses quickly changed nearly every aspect of life."There was more raiding and fewer battles," Shield Chief Gover said. "Horses became deeply integrated into Plains cultures, and changed the way people moved, traded hunted and more."He and Taylor hope that their research will, alongside Indigenous oral traditions, help to shed light on those stories. Taylor, for his part, suspects that the Lehi horse may not be the only set of remains mistakenly shelved with Ice Age animals in museum collections around the country."I think there are a lot more out there like this," he said.
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204101700.htm
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Battling bugs help solve mysteries of weapon evolution
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Remember the first rule of fight club? That's right: You don't talk about fight club. Luckily, the rules of Hollywood don't apply to science. In new published research, University of Arizona researchers report what they learned when they started their own "fight club" -- an exclusive version where only insects qualify as members, with a mission to shed light on the evolution of weapons in the animal kingdom.
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In many animal species, fighting is a common occurrence. Individuals may fight over food, shelter or territory, but especially common are fights between males over access to females for mating. Many of the most striking and unusual features of animals are associated with these mating-related fights, including the horns of beetles and the antlers of deer. What is less clear is which individuals win these fights, and why they have the particular weapon shapes that they do."Biologists have generally assumed that the individual who inflicts more damage on their opponent will be more likely to win a given fight," said John J. Wiens, a professor in the University of Arizona Department of Ecology and Evolutionary Biology, who co-authored two recent studies on bug battles. "Surprisingly, this fundamental assumption had yet to be tested in an experimental study."To find out who wins fights and why, Zachary Emberts, a postdoctoral fellow in Wiens's lab and lead author of both studies, collected 300 male insects known as leaf-footed bugs from the desert near Tucson, Arizona, and staged one-on-one fights.In the summer, these bugs can be found occupying mesquite trees in great numbers, where they crowd the branches and jostle each other over access to females. The males fight using enlarged spikes on their hind legs.So, what does a fight between leaf-footed bugs look like? The best analogy, according to Emberts, is a college wrestling match.Configure"They come up on each other, and they lock each other in, and they will try to squeeze themselves toward one another with their weaponized legs, and that is how they inflict the damage," he said."Think of it as a wrestling match where the opponents sneak knives in," Wiens added.Emberts and Wiens were specifically interested in investigating whether damage influences who wins these fights. For this experiment, published in the journal In addition to the spikes on their legs, the males also have increased thickness in the part of their wings where the spikes usually strike, suggesting that this thickening acts as natural armor during fights. The researchers attached pieces of faux leather to the wings of 50 of their test insects, to provide extra armor against punctures from the spikes of rivals.The researchers found that individuals with this extra armor were 1.6 times more likely to win fights than individuals without extra armor or with the same amount of armor placed in a different location."This tells us that damage is important in who wins the fights," Emberts said. "This had previously been hypothesized, and it makes intuitive sense, but it had not been experimentally shown before."The other major question the researchers wanted to investigate: Why do weapons differ among species? Different species of leaf-footed bugs have different arrangements of spikes on their legs. For example, some sport a lone, big spike, while others have a row of several small ones."Evolution has produced an incredible diversity of weapons in animals, but we don't fully understand why," Emberts said. "And if selection favors weapons that inflict the most damage, then why don't all weapons look the same?"Emberts and Wiens said they chose to look at leaf-footed bugs because the damage from their spikes can easily be measured, as the weapons leave distinct holes in their opponents' wings. The holes don't close up, so once a bug suffers this kind of damage, it has to live with it for the rest of its life."We can directly count and measure the holes they make in their opponents' wings," Wiens said, "and we find that certain weapon morphologies cause more and bigger holes."In their second study, published in the journal They measured the shape and size of hindlimb spikes in 17 species of leaf-footed bugs from around the world. They also measured the average amount of damage on the forewing of each species, including the size and number of punctures from the spikes. The work was done in collaboration with Wei Song Hwang, curator of entomology at the National University of Singapore.The results revealed that some weapons are more effective than others at causing damage to opponents."This tells us that much of the weapon diversity seen in animals that fight over resources and mates can be explained by how well different weapons perform at inflicting damage," Wiens said. "How well the weaponry is performing -- how much damage it inflicts in fights -- is driving its diversification."In other words, certain blade designs provide an evolutionary edge (pun intended). But these results came with a surprise, too."Very different looking weapons can also inflict the same average amount of damage," Emberts said. "This tells us there could be multiple solutions to inflicting damage."For example, two distantly related species of leaf-footed bugs were found to cause almost identical amounts of damage: In one species, the males carry several spines on their femur, while the other species bears a single spine on the tibia."This finding helps answer the question, why don't all weapons evolve to look the same?" Wiens explained. "Rather than evolving towards one optimal weapon shape, there are very different shapes that perform almost as well, solving the mystery of why weapons look so different among species."The authors suggest that the basic principles that explain weapon diversity in leaf-footed bugs might also apply to other groups of animals in which different species have different weapon shapes, such as horned mammals.Emberts and Wiens have begun experiments to tease apart the physiological reasons underlying the evolutionary cost of suffering damage from fights. They say we should stay tuned for more news from UArizona's very own "Bug Fight Club."
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Animals
| 2,021 |
February 4, 2021
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https://www.sciencedaily.com/releases/2021/02/210204101648.htm
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Deadly white-nose syndrome changed genes in surviving bats
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Scientists have found genetic differences between bats killed by white-nose syndrome and bats that survived, suggesting that survivors rapidly evolve to resist the fungal disease, according to a Rutgers-led study with big implications for deciding how to safeguard bat populations.
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White-nose syndrome has killed millions of bats in North America since 2006, following its introduction from Europe. The syndrome, caused by the fungal pathogen Pseudogymnoascus destructans, is arguably the most catastrophic wildlife disease in history. It has led to unprecedented declines in many North American bat species, including the little brown bat ("Our finding that little brown bat populations have evolved, which could be why they survived, has large implications for management of bat populations going forward," said lead author Sarah Gignoux-Wolfsohn, a former postdoctoral associate at Rutgers University-New Brunswick now at the Smithsonian Environmental Research Center in Maryland. "Management decisions, such as whether to treat for white-nose syndrome or protect populations from other detrimental factors, can be informed by knowing which bats are genetically resistant to the disease.""The deployment of vaccines or treatments for the fungus may be most needed in populations with few disease-resistant individuals," said Gignoux-Wolfsohn, who led the study -- published in the journal The disease got its name because the fungus, which grows in cold, dark and damp places, sometimes looks like white fuzz on bats' faces, according to the White-Nose Syndrome Response Team led by the U.S. Fish and Wildlife Service. The fungus attacks the bare skin of bats when they're hibernating and relatively inactive. As it grows, the fungus causes changes in bats that make them become unusually active and burn up fat they need to survive winter. Infected bats may do strange things, such as fly outside in the daytime during winter.Before white-nose syndrome arrived in North America, the little brown bat was one of the most widespread bat species. The disease has caused populations to decline by about 78 percent, killing many hibernating colonies. Still, some populations appear to be recovering after significant declines, likely due to increased disease resistance.Scientists sequenced bat genomes from three hibernating colonies in abandoned mines in New York, New Jersey and Vermont to determine whether little brown bats evolved as a result of the disease. They compared the genomes of bats killed by white-nose syndrome to survivors in recovering populations to identify genetic differences that may be responsible for survival.The bats' evolution appears to have particularly affected genes associated with weight gain before hibernation and behavior during hibernation. Rapid evolution may have allowed the remaining bats to keep hibernating and survive infection that killed off millions of other bats."Evolution is often thought of as a process that happened long ago," Gignoux-Wolfsohn said. "We have found that it has also been happening right in our backyards and barns over the last decade."The scientists are conducting a similar study in Indiana bats (
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Animals
| 2,021 |
February 3, 2021
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https://www.sciencedaily.com/releases/2021/02/210203123525.htm
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Research findings can help to increase population size of endangered species
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The findings of a new study examining the behaviours of alligator and caiman hatchlings have enhanced our understanding of how we can conserve, and increase, the population of endangered crocodilian species.
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At adult size, there are key differences between the American alligator and the closely related spectacled caiman. However, at the time of hatching both species are tiny and might be expected to show similar behaviours in order to avoid being eaten by almost any carnivore around.Now, researchers at the Universities of Lincoln and Vienna have conducted comparative studies between the hatchlings of these crocodilian creatures and found that the alligators are more active and likely to explore their surroundings.The research, conducted at 'Crocodiles of the World', the only zoo in the UK specialising in keeping crocodilians, put American alligator and spectacled caiman hatchlings in unknown environments and presented them with unknown objects.The team found that the alligators moved around much more than the caimans in all conditions and approached the unknown objects closer than the caimans, behaviour which may reflect the strength of maternal protection they receive.Anna Wilkinson is Professor of Animal Cognition at the University of Lincoln, UK, and final author of the study. She said: "The findings of this study are exciting as they have important conservation implications."Several crocodilian species are endangered in the wild and one way to increase their population size is to release captive-bred juveniles into the wild. If the endangered species is a large crocodilian and at the top of the food chain, the juveniles should be allowed to grow to a larger size prior to release as they might have a lower natural predator avoidance."On the flip side, spectacled caimans are an invasive species in the natural range of other crocodilians, including the American alligator, and one reason for their success could be a higher survival rate of their hatchling because of their stronger tendency to avoid predators."First author Dr Stephan Reber, said: "During our research, the movements of the animals were coded automatically using a colour tracking software developed specifically for this study."We used automatic coding because it allows us to catch even very small differences in behaviour. The observed behavioural tendencies of the hatchlings are very reminiscent of those of adults. Adult American alligators are rather self-assured and confident, while adult spectacled caimans are, in comparison, a bit jumpier and more easily spooked."Hatchlings of the two species are probably equally susceptible to predators due to their similar size, but the researchers suggest that the different behaviour observed in the hatchlings is a reflection of the strength of maternal protection.All crocodilians are guarded by a parent (usually the mother) for a considerable amount of time after hatching. The strength of that protection depends on the adult size of the parents.Dr Reber explains: "American alligator mothers have no natural enemies in their habitat and can protect their hatchlings effectively against any predator. On the other hand, adult spectacled caimans have many predators, including cougars, jaguars and giant snakes. Therefore, American alligator hatchlings can afford to be more explorative under their mother's watchful eye, while spectacled caimans probably behave more inconspicuously to avoid attracting attention even if they are guarded."The findings of this study have been published in the eminent science journal
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Animals
| 2,021 |
February 3, 2021
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https://www.sciencedaily.com/releases/2021/02/210203123410.htm
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A deadly fungus is killing frogs, but the bacteria on their skin could protect them
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Researchers in Costa Rica have found that some bacteria on the skin of amphibians prevent growth of the fungus responsible for what has been dubbed 'the amphibian apocalypse'.
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Published in the journal The fungus infects the skin of amphibians, breaking down the cells. As amphibians breathe and regulate water through their skin, infection is often deadly. It is believed that almost 700 species of amphibian are vulnerable to the fungus, and Bd has led to the extinction of 90 amphibian species.In order to investigate why some amphibian populations in Costa Rica were more resilient to Bd that others, a research group led by Dr Adrian Pinto, Professor at the University of Costa Rica sampled the circulating strains of Bd and the skin microbiome of amphibians at different sites.To do this, the research group collected wild amphibians from areas of Costa Rica which had a history of Bd outbreaks. "Bd has previously been widely detected in Costa Rica, but this is the first study to isolate and compare the characteristics of different isolates," said Dr Pinto, "our work showed that the circulating strains of the pathogenic fungus belong to a highly virulent global strain known as BdGPL-2."They found that the bacteria on the skin of some surviving amphibians prevented growth of the fungus in the lab. "Amphibian species that survived decline harbor bacteria on their skin capable of inhibiting the growth of the pathogen. However, this inhibitory capacity varies according to which strain of the fungus is being tested," said Dr Pinto. "These findings suggest that locally adapted skin bacteria may offer protection from the disease."Although the researchers expected to see the highly virulent strain BdGPL-2 in Costa Rica, they did not expect to see so much variation in circulating strains. "We were surprised of the phenotypic variations among the pathogen isolates, including their different responses to the antagonistic bacteria," said Dr Pinto. "Local pathogen adaptations must be considered when designing mitigation strategies for this disease."Dr Pinto hopes to combine their findings with other disease control strategies to protect amphibian populations from decimation by Bd: "We will further study the ability of skin bacteria to protect amphibians against disease, as another tool to combat this plague alongside the creation of climate shelters and fostering the amphibians' own immune system," he said.Costa Rica is one of the countries that suffered a dramatic loss of amphibian species between the 1980 and 1990. In Costa Rica, there are currently 64 species of amphibians in some risk category according to the International Union for the Conservation of Nature. Species classified as critically endangered include the Holdridge's Toad (Incilius holdridgei), a native species found only in the mountain ranges of the central region; The Variable Harlequin Frog (Atelopus varius), a river species very sensitive to Bd, and several species of river tree frogs of the genus Isthmohyla that live in cold currents in high areas, a habitat where Bd proliferates successfully.Amphibians are one of the most diverse groups in the tropics and represent crucial links in food webs. Protecting them keeps ecosystems healthy since biological diversity is the basis for resilient forests, thus helping control pests and zoonotic infections.
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Animals
| 2,021 |
February 3, 2021
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https://www.sciencedaily.com/releases/2021/02/210203123404.htm
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European hibernating bats cope with white-nose syndrome which kills North American bats
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What are the reasons for such a contrast in outcomes? A scientist team led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) has now analysed the humoral innate immune defence of European greater mouse-eared bats to the fungus. In contrast to North American bats, European bats have sufficient baseline levels of key immune parameters and thus tolerate a certain level of infection throughout hibernation. The results are published in the journal
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During infections caused by Pseudogymnoascus destructans (Pd), North American bats arouse frequently from hibernation to trigger a more elaborate immune response, whereas European bats remain dormant, owing, as the new results reveal, to their competent baseline immunity. Not being able to deal with the fungus by baseline immunity causes North American bats to deplete fat stores before the end of winter bnecause of the need for additional and energetically expensive arousals, which ultimately leads to their starvation. European bats may also arouse once in a while when infected but their strong baseline immunity allows them to balance the tight energy budget better during winter hibernation.For this investigation, the scientists went to hibernation sites in Germany and studied 61 mouse-eared bats (Myotis myotis) with varying levels of natural infections by Pseudogymnoascus destructans. The animals were divided into three groups according to the severity of fungal infections (asymptomatic, mild symptoms, severe infection). Body mass and skeletal body size of bats was measured and blood samples taken from torpid animals. In addition, the team monitored in other conspecifics how often infected animals arose from hibernation. "We could show that there is no link between infection and the frequency of waking up from hibernation in the European greater mouse-eared bat," say Marcus Fritze and Christian C. Voigt, bat experts from the Department Evolutionary Ecology at Leibniz-IZW. "This is consistent with the idea that the fungus does not trigger an immune response in European hibernating bats but is rather kept under control by the bats' baseline immunity."In contrast, North American bats such as little brown bats (Myotis lucifugus) arouse frequently when infected by the fungus to elicit an immune response. Frequent arousal and the immune response require energy and prematurely deplete the body's fat stores before the winter has ended. The protein haptoglobin seems key in the bats' fight against the fungus. Haptoglobin is an acute phase protein, which can be produced by bats without large metabolic costs. "Our results demonstrated the central role of haptoglobin in the defence against the fungus. Interestingly, baseline levels of this protein are sufficient to protect the European host against the fungus and there is no need to actively synthesise the protein during the torpid phase," adds Gábor Á. Czirják, wildlife immunologist at the Department of Wildlife Diseases of the Leibniz-IZW.A second key finding of the team's investigation is that heavier European greater mouse-eared bats arouse from hibernation more frequently than lean conspecifics. This seems counterintuitive because each arousal event causes a depletion of fat stores. Well-nourished bats seem to assist their immune system by actively clearing off the external fungal hyphens from their body while being awake for short periods. Thus, heavy bats are in a healthier condition towards the end of hibernation than lean animals. Lean animals cannot afford to arouse as often and thus depend on the efficacy of the baseline immunity to control the fungus. The safety net of a competent immunity keeps European (and Asian) bats alive during infections with P. destructans but proves to be insufficient for North American bats.These results add further evidence that there are differences in the defence strategies against the causative agent of white-nose syndrome in European and North American bat species. Tolerance strategies aim to limit the impact of the fungal infection on the health of animals. Resistance strategies, on the other hand, try to actively reduce the load of pathogens. "Tolerance strategies are effective, as the immune defences of hibernating European mouse-eared bats show," Voigt summarises. "In North American bats, however, this ability is not present to a sufficient degree, possibly because the Pd fungus originated in Europe, giving European species a head start in developing efficient defence mechanisms."
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Animals
| 2,021 |
February 3, 2021
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https://www.sciencedaily.com/releases/2021/02/210203090518.htm
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More mammals are being struck by aircraft each year
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Investigators have published a global review of mammal strikes with aircraft, noting that events have been increasing by up to 68% annually. More mammals were struck during the landing phase of an aircraft's rotation than any other phase, according to the article published in
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By analyzing published information and mammal strike data from national aviation authorities in Australia, Canada, France, Germany, the United Kingdom, and the United States, researchers found that bats accounted for the greatest proportion of strikes in Australia; rabbits and dog-like carnivores in Canada, Germany, and the United Kingdom; and bats and deer in the United States. Average mammal strikes per year ranged from 1.2 to 38.7 across the countries analyzed, for every million aircraft movements.Over 30 years, the estimated cost of damage resulting from reported mammal strikes exceeded $103 million in the United States alone."Mammals are incredibly diverse and those involved in strike events are no exception. As we identified 47 countries which have reported strikes with mammals, the species involved ranged from some of the world's smallest mammals, such as voles, all the way up to the mighty giraffe and included mammals of all sizes in between. As strike events can affect everything from passenger safety, airline economics and local conservation, understanding the species composition and ecology of the local fauna at an airfield is paramount for effective strike mitigation," said lead author Samantha Ball of University College Cork, in Ireland.
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Animals
| 2,021 |
February 1, 2021
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https://www.sciencedaily.com/releases/2021/02/210201155438.htm
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How early tetrapods learned to live -- and eat -- on land
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New research out of the University of Chicago has found evidence that the lobe-finned fish species Tiktaalik roseae was capable of both biting and suction during feeding, similar to modern-day gars. These results, published on Feb. 1 in the
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T. roseae, a creature whose flat skull is reminiscent of an alligator, is a species that lived "right at the cusp of the transition from life in water to life on land," said senior author Neil Shubin, PhD, the Robert R. Bensley Distinguished Service Professor of Organismal Biology and Anatomy at UChicago. Studying its fossilized remains can provide new insights into how key traits for life on land originally evolved."Water is different from air, being much denser and more viscous," said first author Justin Lemberg, PhD, a postdoctoral researcher at UChicago. "This would have created unique problems for animals that were moving out of water and onto land for the very first time, including challenges in locomotion, reproduction, maintaining homeostasis and sensory processing and, of course, feeding. If you can't feed yourself on land, how can you colonize it?"Most aquatic vertebrate species use suction feeding to help pull prey into their mouths. To create suction, many species of fish can expand their skulls laterally to expand their mouths and produce negative pressure. This movement of the skull bones relative to one another is called cranial kinesis."Suction feeding is ineffective on land, because it no longer works from a distance and it's hard to create the pressure seal needed to draw something in," said Lemberg. "So terrestrial vertebrates had to turn to other methods to capture prey. But the fossil evidence for how this happened is ambiguous, much more so than the transition from fin to limb. We wanted to look specifically at the sutures in the T. roseae skull, where the bones fit together, to see if they could tell us how the skull was being used."The research team used advanced new computed tomography (CT) analysis to conduct a detailed examination of the morphology of the T. roseae skull. This allowed them to identify key new traits that had not been seen with other techniques, including sliding joints that would have allowed for the necessary cranial kinesis for the animal to expand its skull laterally to create suction."We discovered Tiktaalik in 2004 and at the time, prepared it with the classical methods, removing rock from the fossil grain by grain," said Shubin. "By the time Justin joined the project, we had access to this CT scanning technology, which lets us see the skull in 3D, taking each part out individually to see its shape and motion. Using the CT analysis transformed how we were able to think about the skull."Investigators noted distinct similarities between T. roseae and earlier work analyzing the skulls of alligator gar, a "living fossil" species previously thought to only use lateral snapping motions to capture prey. In a 2019 study, Lemberg et. al. found that gar use lateral snapping and suction synergistically while feeding, thanks to unique sliding joints in their skulls that help create suction while biting.These similarities led the researchers to believe that T. roseae may have fed in the same way, indicating that this adaptation likely evolved long ago, before animals ever colonized land."The thing that really stuns me is that every innovation, every invention used by tetrapods on land, originally appeared in some form in fish, including lungs, appendages, and now, feeding," said Shubin.Beyond teaching us about the evolution of our distant, fishy ancestors, better understanding of the biology and behavior of creatures like T. roseae can provide new insights into our own anatomy and development."The neat thing about the water-to-land transition is that it's deeply personal to us," said Lemberg. "How did we get to where we are now, and what are some of the evolutionary quirks we've adapted to get here?"Case in point: Lemberg pointed out that when analyzing the range of motion for the T. roseae skull, the three bones that appear to have moved the most are the bones that would eventually become incorporated into the mammalian middle ear."Those three bones in Tiktaalik are what we use to hear sound," Lemberg said. "A little bit of cranial kinesis that's maintained in modern mammals!"
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Animals
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February 1, 2021
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https://www.sciencedaily.com/releases/2021/02/210201113556.htm
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Controls needed to stop zebra mussels invading Great Britain
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New research by Swansea University scientists found that boat ramps facilitate the dispersal of the highly invasive zebra mussel (
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To contain the dispersion of this invasive species Dr Marta Rodriguez-Rey and co-authors suggest in the new study, that strict control measures and target monitoring around boat ramps should be implemented.Invasive bivalves are a problem as they can cause widespread environmental damage, and eradication has proved difficult. The zebra mussel is one of the most damaging invasive bivalves -- it reproduces fast, disperses widely, and damages the economy. In Great Britain, £5 million are lost each year due to pipe fouling and damage to water infrastructures caused by zebra mussels.In this study, the research team examined the distribution of the zebra mussel in Great Britain using a model to generate maps that can predict future dispersion. The model shows that distance to boat ramps is the best way to predict the mussel's distribution -- and mussels are more likely to be present within 3 km upstream of boat ramps.Dr Rodriguez-Rey said: "Using these maps, we detected many areas in most catchments currently without zebra mussel that have a high risk of becoming invaded. For instance, we know this mussel species is already established in some areas in the Thames River but not in all areas, and these free zones should be targeted for monitoring and prevention."
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Animals
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January 29, 2021
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https://www.sciencedaily.com/releases/2021/01/210129120300.htm
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How is human behavior impacting wildlife movement?
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For species to survive in the wild, maintaining connectivity between populations is critical. Without 'wildlife corridors', groups of animals are isolated, unable to breed and may die out. In assessing wildlife connectivity, many aspects of the landscape are measured, but the impact of human behaviour has largely been overlooked. Now, an international team led by the University of Göttingen and Humboldt University Berlin, introduce the concept of 'anthropogenic resistance', which should be studied to ensure sustainable landscapes for wildlife and people for the future. Their perspective article was published in the journal
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Landscapes around the world are increasingly affected by rapid urbanization, deforestation and similar developments driven by human activity. So far, data collection has largely focused on measuring properties of the land -- such as agriculture, urbanization, forestland, crops, or elevation. Other impacts from people are usually lumped together in categories such as population density, or distance from settlements or roads. The researchers propose that it is not merely the presence, absence, or number of people, but what the people are actually doing which affects wildlife movement. In fact, a range of psychological and socioeconomic factors can play a part in 'anthropogenic resistance'. Some examples of these factors include hunting, poaching or supplementary feeding.For their study, the researchers looked at three case studies in detail: wolves in Washington State; leopards in Iran; and large carnivores in central India. The same concept can be applied to other species: for example the Eurasian lynx, which are returning to their historical ranges; or roe deer who use croplands for both shelter and food but reduce their presence during the hunting season. In some parts of the world, cultural and religious beliefs can result in the tolerance of large carnivores, such as tigers and lions, despite substantial livestock losses and threats to human life. The researchers considered effects from beliefs, values and traditions to wildlife in different areas. The authors claim these nuanced differences in human behaviour strongly determine where wildlife may move and persist in a landscape.Professor Niko Balkenhol, from Wildlife Sciences at the University of Göttingen, explains, "Anthropogenic resistance is also relevant to the BearConnect project, which aims to understand the factors that determine connectivity in European populations of the brown bear. Bears are capable of moving across huge distances, as shown by bear JJ1, better known as 'Bruno', who travelled from the Italian Trento region all the way to Bavaria, where he was shot. It is important to note that, although Bruno was able to cross the physical landscape, he was stopped by the severe 'anthropogenic resistance' provided by humans who could not tolerate his behaviour.""Our paper shows that 'anthropogenic resistance' is an important piece of the puzzle for connectivity-planning to ensure the functionality of corridors for wildlife and people," says Dr Trishna Dutta, senior author of the study, also from Wildlife Sciences at the University of Göttingen. Dutta goes on to say: "It reveals that there are advantages for social and natural scientists to collaborate in understanding the effects of 'anthropogenic resistance' in future studies."
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Animals
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January 28, 2021
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https://www.sciencedaily.com/releases/2021/01/210128094233.htm
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Size matters: How the size of a male's weapons affects its anti-predator tactics
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Across many animal species there is great evolutionary pressure on males, who often engage in combat for the rights to copulation. This phenomenon, called sexual selection, often ends up favoring males with larger weapons, such as horns or pincers. Interestingly, scientists have noted that males endowed with smaller weapons adopt alternative reproductive tactics in some species. For example, instead of fighting other more powerful males, they may try to sneak around or disperse in search of a lonely female.
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Variability in sexual behavior according to a male's weapon size has been widely studied. However, it's worth noting that bigger is not always better. Though larger weapons usually help in fights for reproductive rights, they can also be a hinderance because they lower the animal's overall mobility. This has been proven in males of a species of Japanese rhinoceros beetle, who fall prey to predators more easily when their horns, which they use as weapons, are bigger. Could it be that, just as males with smaller weapons adopt alternative sexual tactics, males with larger weapons adopt different anti-predator strategies?In a recent study published in They obtained nearly two hundred male G. cornutus beetles from a laboratory and conducted two types of experiments. First, they pitted male beetles against one of their natural predators, a jumping spider. When attacked by the spider, most beetles froze in place, which seemed to cause the spider to quickly lose interest. On the other hand, the beetles that tried to struggle or run away were repeatedly attacked by the spider and killed. These initial experiments proved that tonic immobility is a useful anti-predator strategy.In the second series of experiments, the researchers measured the size of the mandibles of male beetles and then tried to get them to exhibit tonic immobility by gently touching their abdomen with a thin stick. Unlike previous behavioral studies, which exclusively focused on the duration of tonic immobility once triggered, the team also quantified the frequency of tonic immobility. Whereas no statistical relationship was found between weapon size and tonic immobility duration, a link was very apparent between weapon size and frequency; individuals with larger mandibles were generally more prone to exhibit tonic immobility when stimulated. Excited about the results, Dr. Kentarou Matsumura remarks: "For animals that fight with weapons, the costs of having larger weapons are well known. However, this is the first time we have scientifically determined that anti-predator tactics can vary among males according to their weapon size."The results and the research strategy adopted by the team will help biologists unravel the mysteries of the evolution of behaviors, as Miyatake explains: "As the first study of predator-avoidance tactics in animals that have weapons for male-to-male fighting, we believe this is an opportunity to delve deeper on the relationship between the evolution of weapons and anti-predator behavior." Miyatake also states that these new discoveries will spawn a new research topic in the evolution of survival tactics, which in turn will increase our overall scientific understanding of this challenging field in the future.What other fascinating evolutionary secrets could be hiding out there in the behaviors of different animals? Let us hope this study acts as a springboard for finding the answers!
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Animals
| 2,021 |
January 28, 2021
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https://www.sciencedaily.com/releases/2021/01/210128091217.htm
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Crunch! Underwater acoustics expose 'shell-crushing' sounds in a large marine predator
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"Shell-crushing" -- exactly what it sounds like -- is a predatory mode used by numerous marine life from crabs to octopuses to large fishes and mammals when they eat hard-shelled mollusks like clams, oysters and conchs. These predators have to break apart the shell using robust claws or fortified jaws to access the prey's soft tissues.
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Despite its prevalence in the marine environment, this feeding behavior has remained elusive to study remotely, particularly for larger marine animals that destroy shells almost completely, leaving behind little trace. Moreover, because they are highly mobile, scientists have difficulty in directly observing their foraging habits, which is why the ecology of shell-crushing (durophagy) remains poorly understood in larger marine predators and the ecosystems with which they interact. So, there is little understanding of where or when this happens.Using the whitespotted eagle ray (Aetobatus narinari) as a model, a team of scientists led by Florida Atlantic University's Harbor Branch Oceanographic Institute in collaboration with FAU's College of Engineering and Computer Science; Mote Marine Laboratory & Aquarium; and the Florida Institute of Technology, are the first to use passive acoustics to characterize how they consume hard-shelled mollusk prey in a controlled environment.Scientists both quantified and classified shell-crushing by monitoring underwater sounds using acoustic recorders. Results, published in the "Interactions between molluscan predators and shellfish often occur in low-visibility estuarine waters. Scientists need alternative non-visual based methods to continuously monitor, gather and document critical data that may have serious conservation ramifications," said Matt Ajemian, Ph.D., lead author, an assistant research professor at FAU's Harbor Branch and head of the Fisheries Ecology and Conservation (FEC) Lab, who worked with FAU Harbor Branch co-authors Laurent Chérubin, Ph.D., an associate research professor; and Breanna DeGroot, M.S., research coordinator. "Passive acoustics-based documentation of shell-crushing behavior has not been seriously considered as a tool to identify the ecological role of large, mobile molluscivores before this study. We knew from previous experience with these animals that the cracks they made during feeding were loud, almost like an explosion, but there were no data to support it at the time. That's what led us to conduct this initial study."Whitespotted eagle rays consume a wide variety of mollusk species, including both bivalves and gastropods. For the study, scientists recorded a total of 434 prey items being eaten by rays, spanning eight species of hard-shelled mollusks. On the menu: hard clams, banded tulip, crown conch, lettered olive, Florida fighting conch, lightning whelk, pear whelk and horse conch."Mollusks vary in texture, thickness and strength. The differences we observed in consumption signals and behavior associated with the two primary prey types analyzed are likely due to variations in these shell shapes," said Kim Bassos-Hull, M.Sc., co-author and senior biologist with Mote Marine Lab's Sharks & Rays Conservation Research Program. "It was clear that hard clams took a considerably longer time to process than banded tulip shells and all other gastropods. This was likely driven by the greater number of fractures rays needed to implement during processing and winnowing of hard clams presumably to access the prey's soft tissues."Signal characteristics of simulated crushing of hard clams in the field, which the researchers conducted by crushing clams by hand using modified heavy-duty pliers, also were similar to those recorded in the large, circular saltwater habitat."It's obviously hard to get a ray to eat on command in a particular time and place, so we had to get somewhat creative with the field testing," said Ajemian.Data from this study are critically important with respect to molluscan shellfish, which provide high-quality and high-value seafood to humans, and beneficial ecosystem services, yet sources of natural mortality from large predators are largely unknown for both natural and restored populations."The passive acoustics approach demonstrated in our study provides a unique, less-intrusive platform to remotely and directly observe predation events like shell fracture in the aquatic environment and support surveillance techniques to quantify predator-induced losses to these valuable resources, even in challenging environmental conditions," said Chérubin.The team is hoping this technology will be of utility in monitoring how many clams are being eaten by large predators like rays as restoration efforts ramp up around the state of Florida."We still have a lot of work to do on the automated detection-classification side of things, but this work brings us closer to remotely capturing predation in these elusive species," said Ajemian.
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Animals
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January 27, 2021
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https://www.sciencedaily.com/releases/2021/01/210127083901.htm
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New light shed on behavior of giant carnivorous dinosaur Spinosaurus
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New research from Queen Mary University of London and the University of Maryland, has reignited the debate around the behaviour of the giant dinosaur Spinosaurus.
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Since its discovery in 1915, the biology and behaviour of the enormous Spinosaurus has puzzled palaeontologists worldwide. It was recently argued that the dinosaur was largely an aquatic predator, using its large tail to swim and actively pursue fish in the water.The new study, published today in Palaeontologia Electronica, challenges this recent view of Spinosaurus suggesting that whilst it likely fed from the water, and may have swum, it wasn't well adapted to the life of an aquatic pursuit predator. Instead it was like a giant (if flightless) heron or stork -- snatching at fish from the shoreline while also taking any other small available prey on land or in water.The researchers compared the features of Spinosaurus with the skulls and skeletons of other dinosaurs and various living and extinct reptiles that lived on land, in the water or did both. They found that whilst there were several pieces of evidence that contradicted the aquatic pursuit predator concept, none contradicted the wading heron-like model, and various lines of evidence actively supported it.Dr David Hone, Senior Lecturer at Queen Mary and lead author on the project said: "The biology and ecology of Spinosaurus has been troubling palaeontologists for decades. Some recent studies have suggested that it was actively chasing fish in water but while they could swim, they would not have been fast or efficient enough to do this effectively. Our findings suggest that the wading idea is much better supported, even if it is slightly less exciting."Co-author Tom Holtz, Principal Lecturer in Vertebrae Paleontology, University of Maryland, said: "Spinosaurus was a bizarre animal even by dinosaur standards, and unlike anything alive today, so trying to understand its ecology will always be difficult. We sought to use what evidence we have to best approximate its way of life. And what we found did not match the attributes one would expect in an aquatic pursuit predator in the manner of an otter, sea lion, or short-necked plesiosaur."One of the key pieces of evidence unearthed by the researchers related to the dinosaur's ability to swim. Spinosaurus was already shown to be a less efficient swimmer than a crocodile, but also has fewer tail muscles than a crocodile, and due to its size would have a lot more drag in the water.Dr Hone said: "Crocodiles are excellent in water compared to land animals, but are not that specialised for aquatic life and are not able to actively chase after fish. If Spinosaurus had fewer muscles on the tail, less efficiency and more drag then it's hard to see how these dinosaurs could be chasing fish in a way that crocodiles cannot."Dr Holtz added: "We certainly add that the evidence points to Spinosaurus feeding partly, even mostly, in the water, probably more so than any other large dinosaur. But that is a different claim than it being a rapid swimmer chasing after aquatic prey." Though as Dr Hone concludes: "Whilst our study provides us with a clearer picture of the ecology and behaviour of Spinosaurus, there are still many outstanding questions and details to examine for future study and we must continue to review our ideas as we accumulate further evidence and data on these unique dinosaurs. This won't be the last word on the biology of these amazing animals."Originally found in Egypt, Spinosaurus is thought to be one of the largest carnivorous dinosaurs to exist probably reaching over 15 m in length. The first known Spinosaurus fossils were destroyed by Allied bombing during World War II, which has hampered palaeontologist's attempts to understand these unusual creatures. More recently the dinosaur found fame in the 2001 film Jurassic Park III, where it battles and defeats a Tyrannosaurus rex.
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Animals
| 2,021 |
January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126171644.htm
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When push comes to shove, what counts as a fight?
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Biologists often study animal sociality by collecting observations about several types of behavioral interactions. These interactions can be things like severe fights, minor fights, cooperative food sharing, or grooming each other.
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But to analyze animal behavior, researchers need to make decisions about how to categorize these interactions and how to code these behaviors during data collection. Turns out, this question can be complicated.Researchers at the University of Cincinnati dug into this tricky question while studying monk parakeets. In new research, published in the journal "Biologists have to deal with this question: are the behaviors that we categorize as unique actually perceived as unique by the animals?" Hobson said. "How do the animals classify those behaviors?"Biases can easily lead researchers astray in making these judgement calls. "If you look at chimpanzees, smiling is an aggressive behavior. But in humans, smiling is friendly," said van der Marel. "The behaviors look similar to us but the nuances of how the behaviors are used are very different."Monk parakeets are highly social parrots that live in large colonies where they often interact with other individuals. The parakeets spend a large proportion of the day fighting, especially top-ranked birds, which makes it easy to distinguish them from birds ranked lower in the dominance hierarchy, said O'Connell. The birds demonstrate aggression in many ways. They bite, of course. But monk parakeets also like to take another parrot's perch through menace or sheer force.UC biologists observed two types of this "king of the hill" behavior: "displacements," where one bird lunges at another bird and can bite to force that bird away, and "crowding," where a threatened bird moves before an aggressor is within biting range. The team coded these behaviors as distinct because they appeared to differ in the level of aggression, with displacements appearing as a more severe form of aggression with a higher potential for injury.The parakeets also used these behaviors somewhat differently, with displacements occurring much more often than the crowding.The question is: were these behaviors essentially used in the same ways by the birds, so that they could be treated as the same types of events in later analyses?Pooling two behaviors has major research benefits such as creating a richer dataset for future analyses. But pooling also carries a risk -- by generalizing, scientists could be losing nuances of behaviors that convey important information when considered alone, Hobson said.To get to the bottom of this question, the team turned to computational analysis. They created a new computer model that compared the real aggression patterns to ones that were randomized. This approach allowed the team to test whether treating the two behaviors as interchangeable caused any changes in the social structure. "On top of being a great lab bonding experience, it was an exciting opportunity to learn how to use simulations to help answer research questions" Prasher said.In the UC study, their computational analysis supported pooling the two behaviors. For the UC team, these results will help them plan their future analyses as they work to understand the complex social lives of these parakeets. More broadly, van der Marel said the new framework can also help other animal-behavior researchers make informed and data-driven decisions about when to pool together behaviors and when to separate them.
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Animals
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January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126171620.htm
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Ocean toxin a heartbreaking threat for sea otters
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Heart disease is a killer threat for southern sea otters feasting on domoic acid in their food web, according to a study led by the University of California, Davis.
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The study, published in the journal "Sea otters are an amazing indicator of what's happening in the coastal environment, not just to other marine animals, but to us, too, especially on the issue of domoic acid," said Christine K. Johnson, director of the EpiCenter for Disease Dynamics in the One Health Institute at the UC Davis School of Veterinary Medicine and senior author of the study.Domoic acid is a neurotoxin that accumulates in the food web, contaminating crabs and clams -- common prey for sea otters. It is produced by harmful algal blooms, which typically occur when water is unusually warm. For example, a massive warm water "blob" in 2015 created a widespread toxic bloom along the West Coast, causing domoic acid levels to spike and forcing the closure of that season's Dungeness crab fishery.Climate change projections indicate that toxic blooms and domoic acid exposure will continue to rise. The world's ocean temperatures in 2020 were the third highest on record, and all five of the oceans' hottest years on record occurred in the past five years.To identify the ecological drivers of heart disease, the scientists combined several domoic acid datasets with detailed life history data from 186 free-ranging southern sea otters in California from 2001 to 2017. Of those animals, necropsy reports show that heart disease was a cause of death for 34 of the 48 otters that died during that time.The scientists found that domoic acid exposure increased a sea otter's risk of dying with heart disease 1.7-fold. The risk is up to 2.5 times greater for otters consuming a high proportion of crab and clam, which accumulate domoic acid in their tissues, helping it persist in the food web.The study was also the first to demonstrate a disturbing and unexpected trend: Domoic acid exposure is especially detrimental for prime-age adult sea otters, whose survival is vital for population growth."That's worrisome for the long-term population recovery of southern sea otters, which are a threatened species," said lead author Megan Moriarty, a wildlife veterinarian who conducted this research for her Ph.D. in epidemiology at UC Davis. "This study emphasizes that domoic acid is a threat that isn't going away. It's a food web toxin and is pretty pervasive."Infection with Toxoplasma gondii, a parasite associated with wild and feral cat feces on land that makes its way to the ocean, also increased the risk of fatal heart disease 2.4-fold.Co-author Melissa Miller, a veterinarian and pathologist with the California Department of Fish and Wildlife and a UC Davis One Health Institute affiliate, recently led a separate study analyzing the causes of death of sea otters."Improving our understanding of the effects of domoic acid on the health and population recovery of southern sea otters is extremely important" said Miller of the domoic acid study. "Given their unique biology and specialized diet, sea otters are extremely vulnerable to toxic algal blooms, which are likely to worsen with climate change. So the results of this work have far-reaching implications."The study was funded by the Morris Animal Foundation and National Science Foundation.
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Animals
| 2,021 |
January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126134026.htm
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Vaccine shows potential against deadly leptospirosis bacteria
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Scientists have designed a single-dose universal vaccine that could protect against the many forms of leptospirosis bacteria, according to a study published today in
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An effective vaccine would help prevent the life-threatening conditions caused by leptospirosis, such as Weil's disease and lung haemorrhage, which are fatal in 10% and 50% of cases, respectively.Leptospirosis is caused by a diverse group of spirochetes called leptospires. A broad range of mammals, including rats, harbour the bacteria in their kidneys and release them into the environment through their urine. Humans and animals can then get infected after coming into contact with contaminated water or soil. In addition to having a major impact on the health of vulnerable human populations, leptospirosis is an economically important animal health problem, making it a significant One Health challenge. This means that collaborative efforts are needed across disciplines and sectors to improve public health outcomes against leptospirosis infection.The Leptospira family of bacteria is made up of 64 species with 300 different varieties (called serovars). This makes developing a vaccine challenging, because researchers need to find a common feature of the bacteria that will trigger an immune response."We have recently identified a novel protein called FcpA in the flagella of Leptospira which enables it to move and penetrate human and animal tissues," explains first author Elsio Wunder Jr, Associate Research Scientist in Epidemiology (Microbial Diseases) at Yale School of Public Health, Yale University, New Haven, US. "With this study, we wanted to see whether using engineered Leptospira that lacks a functional FcpA molecule has the potential for a vaccine that could provide major public health benefit."The mutated FcpA Leptospira was tested as an attenuated vaccine -- a live vaccine that cannot cause disease. After the vaccine was given to hamsters and mice, it disseminated throughout the body before being cleared within seven days in the hamsters and after two weeks in the mice. No traces of the mutated Leptospira could be detected in kidney tissue or blood after this time point, showing that the attenuated vaccine is cleared by the immune system before it results in disease or death.To test whether the vaccine candidate could protect against all types of Leptospira infection, they tested a single dose of the mutant Leptospira and compared this against heat-killed Leptospira to see whether they could prevent infection and disease by a range of similar and different serovars. Immunisation with the heat-killed vaccine gave partial protection against similar serovars but not against different serovars of Leptospira. By contrast, the attenuated vaccine (mutated Leptospira) provided cross-protection against serovars belonging to three different species of Leptospira, which encompass the majority of serovars of importance to human and animal health.Further analysis of the mice and hamsters after vaccination showed that they generated antibodies that recognised a wide range of proteins across the different species of Leptospira. Moreover, by studying the antibody response in detail, the team identified 41 different proteins that could be targets for future vaccines. The majority of these proteins (70%) looked similar across all 13 disease-causing species of Leptospira studied, suggesting they are likely to be important to the microbes' survival and would make effective future vaccine candidates."In this proof-of-concept study, we have shown that a universal leptospirosis vaccine candidate can prevent both death and kidney colonisation in animal models," concludes author Albert Ko, Department Chair and Professor of Epidemiology (Microbial Diseases) at Yale School of Public Health. "These findings take us one step closer to achieving the holy grail for the field, which is an effective vaccine that protects against the many Leptospira species and can be deployed as a broad solution to the human and animal health challenge caused by leptospirosis."
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Animals
| 2,021 |
January 25, 2021
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https://www.sciencedaily.com/releases/2021/01/210125113121.htm
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Dinosaur embryo find helps crack baby tyrannosaur mystery
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They are among the largest predators ever to walk the Earth, but experts have discovered that some baby tyrannosaurs were only the size of a Border Collie dog when they took their first steps.
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The first-known fossils of tyrannosaur embryos have shed light on the early development of the colossal animals, which could grow to 40 feet in length and weigh eight tonnes.A team of palaeontologists, led by a University of Edinburgh researcher, made the discovery by examining the fossilised remains of a tiny jaw bone and claw unearthed in Canada and the US.Producing 3D scans of the delicate fragments revealed that they belonged to baby tyrannosaurs -- cousins of The team's findings suggest that tyrannosaur eggs -- the remains of which have never been found -- were around 17 inches long. This could aid efforts to recognise such eggs in the future and gain greater insights into the nesting habits of tyrannosaurs, researchers say.The analysis also revealed that the three-centimetre-long jaw bone possesses distinctive tyrannosaur features, including a pronounced chin, indicating that these physical traits were present before the animals hatched.Little is known about the earliest developmental stages of tyrannosaurs -- which lived more than 70-million-years-ago -- despite being one of the most studied dinosaur families. Most tyrannosaur fossils previously studied have been of adult or older juvenile animals.The study, published in the Dr Greg Funston, of the University of Edinburgh's School of GeoSciences, who led the study, said: "These bones are the first window into the early lives of tyrannosaurs and they teach us about the size and appearance of baby tyrannosaurs. We now know that they would have been the largest hatchlings to ever emerge from eggs, and they would have looked remarkably like their parents -- both good signs for finding more material in the future. "
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Animals
| 2,021 |
January 25, 2021
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https://www.sciencedaily.com/releases/2021/01/210125094057.htm
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Women influenced coevolution of dogs and humans
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Man's best friend might actually belong to a woman.
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In a cross-cultural analysis, Washington State University researchers found several factors may have played a role in building the mutually beneficial relationship between humans and dogs, including temperature, hunting and surprisingly -- gender."We found that dogs' relationships with women might have had a greater impact on the dog-human bond than relationships with men," said Jaime Chambers, a WSU anthropology Ph.D. student and first author on the paper published in the While dogs are the oldest, most widespread domesticated animal, very few anthropologic studies have directly focused on the human relationship with canines. Yet when the WSU researchers searched the extensive collection of ethnographic documents in the Human Relations Area Files database, they found thousands of mentions of dogs.Ultimately, they located data from more than 844 ethnographers writing on 144 traditional, subsistence-level societies from all over the globe. Looking at these cultures can provide insight into how the dog-human relationship developed, Chambers said."Our modern society is like a blip in the timeline of human history," she said. "The truth is that human-dog relationships have not looked like they do in Western industrialized societies for most of human history, and looking at traditional societies can offer a wider vision."The researchers noted specific instances that showed dogs' utility, or usefulness, to humans, and humans' utility to dogs as well as the "personhood" of dogs -- when canines were treated like people, such as being given names, allowed to sleep in the same beds or mourned when they died.A pattern emerged that showed when women were more involved with dogs, the humans' utility to dogs went up, as did the dogs' personhood.Another prevalent trend involved the environment: the warmer the overall climate, the less useful dogs tended to be to humans."Relative to humans, dogs are really not particularly energy efficient," said Robert Quinlan, WSU anthropology professor and corresponding author on the paper. "Their body temperature is higher than humans, and just a bit of exercise can make them overheat on a hot day. We saw this trend that they had less utility to humans in warmer environments."Quinlan noted there were some exceptions to this with a few dog-loving cultures in the tropics, but it was a fairly consistent trend.Hunting also seemed to strengthen the dog-human connection. In cultures that hunted with dogs, they were more valued by their human partners: they were higher in the measures of dogs' utility to humans and in personhood. Those values declined, however, when food production increased whether it was growing crops or keeping livestock. This finding seemed to go against the commonly held perception of herding dogs working in concert with humans, but Quinlan noted that in many cultures, herding dogs often work alone whereas hunting requires a more intense cooperation.This study adds evidence to the evolutionary theory that dogs and humans chose each other, rather than the older theory that humans intentionally sought out wolf pups to raise on their own. Either way, there have been clear benefits for the dogs, Chambers said."Dogs are everywhere humans are," she said. "If we think that dogs are successful as a species if there are lots of them, then they have been able to thrive. They have hitched themselves to us and followed us all over the world. It's been a very successful relationship."
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Animals
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January 22, 2021
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https://www.sciencedaily.com/releases/2021/01/210122140630.htm
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From fins to limbs
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When tetrapods (four-limbed vertebrates) began to move from water to land roughly 390 million years ago it set in motion the rise of lizards, birds, mammals, and all land animals that exist today, including humans and some aquatic vertebrates such as whales and dolphins.
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The earliest tetrapods originated from their fish ancestors in the Devonian period and are more than twice as old as the oldest dinosaur fossils. They resembled a cross between a giant salamander and a crocodile and were about 1-2 meters long, had gills, webbed feet and tail fins, and were still heavily tied to water. Their short arms and legs had up to eight digits on each hand and foot and they were probably ambush predators, lurking in shallow water waiting for prey to come near.Scientists know how the fins of fish transformed into the limbs of tetrapods, but controversies remain about where and how the earliest tetrapods used their limbs. And, while many hypotheses have been proposed, very few studies have rigorously tested them using the fossil record.In a paper published January 22 in To reconstruct how limbs of the earliest known tetrapods functioned, Molnar, Pierce and co-authors John Hutchinson (Royal Veterinary College), Rui Diogo (Howard University), and Jennifer Clack (University of Cambridge) first needed to figure out what muscles were present in the fossil animals. A challenging task as muscles are not preserved in fossils, and the muscles of modern fish fins are completely different from those of tetrapod limbs. The team spent several years trying to answer the question, how exactly did the few simple muscles of a fin become dozens of muscles that perform all sorts of functions in a tetrapod limb?"Determining what muscles were present in a 360-million-year-old fossil took many years of work just to get to the point where we could begin to build very complicated musculoskeletal models," said Pierce. "We needed to know how many muscles were present in the fossil animals and where they attached to on the bones so we could test how they functioned."They built three-dimensional musculoskeletal models of the pectoral fin in To determine how the fins and limbs worked, the researchers used computational software originally developed to study human locomotion. This technique had been used recently to study locomotion in the ancestors of humans and also dinosaurs like Manipulating the models in the software, the team were able to measure two functional traits: the joint's maximum range of motion and the muscles' ability to move the fin or limb joints. The two measurements would reveal trade-offs in the locomotor system and allow the researchers to test hypotheses of function in extinct animals.The team found the forelimbs of all terrestrial tetrapods passed through three distinct functional stages: a "benthic fish" stage that resembled modern lungfish, an "early tetrapod" stage unlike any extinct animal, and a "crown tetrapod" stage with characteristics of both lizards and salamanders."The fin from "That was perhaps the most surprising," said Molnar. "I thought The results showed that early tetrapod limbs were more adapted for propulsion rather than weight bearing. In the water, animals use their limbs for propulsion to move themselves forward or backward allowing the water to support their body weight. Moving on land, however, requires the animal act against gravity and push downward with their limbs to support their body mass.This doesn't mean that early tetrapods were incapable of moving on land, but rather they didn't move like a modern-day living tetrapod. Their means of locomotion was probably unique to these animals that were still very much tied to the water, but were also venturing onto land, where there were many opportunities for vertebrate animals but little competition or fear from predators."These results are exciting as they independently support a study I published last year using completely different fossils and methods," said Pierce. "That study, which focused on the upper arm bone, indicated that early tetrapods had some capacity for land movement but that they may not have been very good at it."The researchers are closer to reconstructing the evolution of terrestrial locomotion, but more work is needed. They plan to next model the hind limb to investigate how all four limbs worked together. It has been suggested that early tetrapods were using their forelimbs for propulsion, but modern tetrapods get most of their propulsive power from the hind limb."We plan to look for any evidence of a shift from forelimb driven locomotion toward hind limb driving locomotion, like modern tetrapods," said Molnar. Looking at the forelimb and hind limb together could reveal more about the transition from water to land and how tetrapods eventually came to dominate the terrestrial realm.
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Animals
| 2,021 |
January 22, 2021
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https://www.sciencedaily.com/releases/2021/01/210122140619.htm
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Rediscovery of the 'extinct' Pinatubo volcano mouse
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In June 1991, Mount Pinatubo, a volcanic peak on the Philippine Island of Luzon, literally blew its top. It was the second-most powerful volcanic eruption of the 20th century, ten times stronger than Mount Saint Helens, and its effects were devastating. Lava and ash spewed into the surrounding environment in the Zambales Mountains, pooling in layers up to 600 feet thick in the valleys. Following the eruption, powerful typhoons and monsoon rains triggered landslides and ash flows that continued for many months. Eight hundred people lost their lives, and the lush forests that covered the mountain prior to the eruption were destroyed or severely damaged. In recent years, scientists returned to the region to survey the surviving mammal populations, and in a new paper in the Philippine Journal of Science, the team announced the rediscovery of a species of mouse that had long been feared to be extinct.
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"When Pinatubo blew up, probably the last thing on anyone's mind was that a little species of mouse was thought to live only on that one mountain, and might well have become extinct as a result. What we've learned subsequently really blew us away," says Larry Heaney, the Negaunee Curator of Mammals at Chicago's Field Museum and one of the paper's authors.In early 2011 and again in 2012, twenty years after the eruption, Field Museum researcher Danilo (Danny) Balete went to Mt. Pinatubo to study its mammal fauna. Over the course of several months, Balete and his team of field assistants (including local men from the Aeta tribe) surveyed the mammals on the mountain, from the bottom to near the top where the forest had been devastated by the eruption."Most of our field work on Luzon and elsewhere in the Philippines has been in natural forested habitats where mammals are most common" says Eric Rickart, Curator of Vertebrates at the Natural History Museum of Utah and lead author on the paper, "but Danny couldn't pass up an opportunity to see how mammals were faring on Mt. Pinatubo."There were no surveys of the mammals on Mt. Pinatubo prior to the eruption. However, specimens housed in the US National Museum of Natural History provided some records from lower elevations around the mountain. "Most of these early records were for common species of bats collected in the 1950s," says Heaney, "but one specimen was particularly intriguing-a small rodent that became the type specimen, and only example, of a new species described in 1962 as Apomys sacobianus, the Pinatubo volcano mouse."Conditions on Mt. Pinatubo were very harsh, and the survey work by Balete's team was both grueling and dangerous. Even after 20 years, evidence of the eruption was everywhere. The landscape was very unstable due to the constantly eroding ash and lahar deposits that made working in the steep terrain hazardous. It also greatly slowed the process of plant succession. Vegetation was a sparse mix of native and non-native plants, dense stands of grass (including bamboo), shrubs, low-growing vines, and few trees-all the characteristic of early stage second-growth habitat. It was a far cry from the old-growth tropical forest that covered the mountain before the eruption.Field surveys of small non-flying mammals elsewhere on Luzon have revealed that old-growth forests contain a great variety of native species and few, if any, non-native "pest" species of rats. But in heavily disturbed second-growth habitats, particularly areas near croplands, the reverse is the case-non-native rats are most abundant, and there are only a few hardy native species. "We thought the work on Pinatubo would confirm this general pattern, so we expected to see few if any of the native species," says Rickart.A specific motivation for the Pinatubo survey was to discover the fate of Apomys sacobianus, the Pinatubo volcano mouse. "After the eruption of Pinatubo, we looked for this mouse on other peaks in the Zambales Mountains but failed to find it," notes Heaney, "suggesting a very limited geographic distribution for the species. We thought the volcano might be the only place this mouse lived." And based on expectations from islands elsewhere, at the time it seemed possible that the species might have been lost because of the eruption.However, the survey of Pinatubo produced some very surprising results-a total of 17 species were documented, including eight bats, seven rodents (five native and two non-native species), and even two large mammals (wild pig and deer). Contrary to expectations, non-native rats were not at all common and were restricted to areas near Aeta croplands where such agricultural pests are often most abundant. Despite the fact that all areas surveyed supported sparse, scrubby second-growth vegetation rather than forest, native rodents were abundant everywhere.Most surprising of all, the most abundant species, overwhelmingly, was the volcano mouse Apomys sacobianus. Far from being wiped out by the eruption, this species was thriving in this greatly disturbed landscape along with other native species that also have a high tolerance for disturbance. "For some time, we've known that many of the small mammals of the Philippines can tolerate habitat disturbance, both natural and human-caused," Rickart says, "but most of them are geographically widespread, not locally endemic species which usually are viewed by conservation biologists as highly vulnerable."As Mt. Pinatubo recovers from the damage done by the eruption, the forests will return and other species of mammals will move in. "Mt. Pinatubo could be a wonderful place to establish a long-term project to monitor habitat recovery and community re-assembly following the eruption," says Rickart, "such information would be helpful in efforts to regenerate the many areas that have been deforested by people."After completing the Mt. Pinatubo mammal survey, Danny Balete returned to the Field Museum where he organized specimens and data from the survey, made some early notes for an eventual publication, and then set them aside to finish later. After he suddenly died in 2017 at age 56, Rickart and Heaney say that they picked up and completed the study as a tribute to Balete, who is now recognized as one of the most important figures in Philippine biodiversity science for his extensive research contributions, mentoring of younger colleagues, and promoting enjoyment of nature throughout the Philippines."Knowing that a species once thought to be vulnerable, even feared to be extinct, is actually thriving is the finest tribute to Danny that we can imagine," adds Heaney.
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Animals
| 2,021 |
January 22, 2021
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https://www.sciencedaily.com/releases/2021/01/210122112310.htm
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Chimpanzee friends fight together to battle rivals
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Chimpanzees, one of the closest relatives of humans, cooperate on a group level -- in combative disputes, they even cooperate with group members to whom they are not related. Those involved in fights with neighbouring groups put themselves at risk of serious injury or even death.
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Within the context of the Tai Chimpanzee Project researchers observed three chimpanzee communities in Tai National Park in Cote d'Ivoire documenting social relationships, territory range and intergroup encounters amongst others. "We have been able to analyze almost 500 vocal and physical battles from the last 25 years with participation of at least one of the three habituated communities, some of which have caused severe injury or death," says Liran Samuni, the first author of the study.The study showed that males, as well as females participate in the battles and that three factors increased the likelihood of participation in the intergroup encounter when there were many individuals participating, when maternal kin joined and when non-kin social bond partners were present. "It seems chimpanzees not only consider the sheer number in their sub-group when moving into battle, but they consider the presence of a trusted group member, who will support them in case of an attack," adds Catherine Crockford, senior author of the study. "These results suggest," Liran Samuni continues, "that the link between strong, enduring social relationships and costly collective acts is not uniquely human, but is present in one of our closest living relatives, the chimpanzee.""This study is part of a series of several investigations linking in-group cooperation with out-group competition," explains Roman Wittig, director of the Tai Chimpanzee Project and senior author of the studies. "We were able to show that out-group competition reduces chimpanzees' reproduction and their territory size. On the other hand, out-group competition increases in-group cohesion and, likely facilitated by the neurohormone oxytocin, reduces the likelihood of defection in battle."Data from the Tai Chimpanzee Project, with four neighboruing communities observed on a daily basis, will be a key source for scientific investigations into the ultimate and proximate causes of group-level cooperation. "The Tai chimpanzees can teach us," Roman Wittig points out, "what social tools enable human's unique capacity for large-scale cooperation with non-kin."
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Animals
| 2,021 |
January 20, 2021
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https://www.sciencedaily.com/releases/2021/01/210120204033.htm
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New starfish-like fossil reveals evolution in action
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Researchers from the University of Cambridge have discovered a fossil of the earliest starfish-like animal, which helps us understand the origins of the nimble-armed creature.
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The prototype starfish, which has features in common with both sea lilies and modern-day starfish, is a missing link for scientists trying to piece together its early evolutionary history.The exceptionally preserved fossil, named Cantabrigiaster fezouataensis, was discovered in Morroco's Anti-Atlas mountain range. Its intricate design -- with feathery arms akin to a lacework -- has been frozen in time for roughly 480 million years.The new species is unusual because it doesn't have many of the key features of its contemporary relatives, lacking roughly 60% of a modern starfish's body plan.The fossil's features are instead a hybrid between those of a starfish and a sea lily or crinoid -- not a plant but a wavy-armed filter feeder which fixes itself to the seabed via a cylindrical 'stem'.The discovery, reported in The find also means scientists can now use the new find as a template to work out how it evolved from this more basic form to the complexity of their contemporaries."Finding this missing link to their ancestors is incredibly exciting. If you went back in time and put your head under the sea in the Ordovician then you wouldn't recognize any of the marine organisms -- except the starfish, they are one of the first modern animals," said lead author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences.Modern starfish and brittle stars are part of a family of spiny-skinned animals called the echinoderms which, although they don't have a backbone, are one of the closest group of animals to vertebrates. Crinoids, and otherworldly creatures like the sea urchins and sea cucumbers are all echinoderms.The origin of starfish has eluded scientists for decades. But the new species is so well preserved that its body can finally be mapped in detail and its evolution understood. "The level of detail in the fossil is amazing -- its structure is so complex that it took us a while to unravel its significance," said Hunter.It was Hunter's work on both living and fossil echinoderms that helped him spot its hybrid features. "I was looking at a modern crinoid in one of the collections at the Western Australian Museum and I realised the arms looked really familiar, they reminded me of this unusual fossil that I had found years earlier in Morocco but had found difficult to work with," he said.Fezouata in Morocco is something of a holy grail for palaeontologists -- the new fossil is just one of the many remarkably well preserved soft-bodied animals uncovered from the site.Hunter and co-author Dr Javier Ortega-Hernández, who was previously based at Cambridge's Department of Zoology and is now based at Harvard University, named the species Cantabrigiaster in honour of the long history of echinoderm research at their respective institutions.Hunter and Ortega-Hernández examined their new species alongside a catalogue of hundreds starfish-like animals. They indexed all of their body structures and features, building a road map of the echinoderm skeleton which they could use to assess how Cantabrigiaster was related to other family members.Modern echinoderms come in many shapes and sizes, so it can be difficult to work out how they are related to one another. The new analysis, which uses extra-axial theory -- a biology model usually only applied to living species -- meant that Hunter and Ortega-Hernández could identify similarities and differences between the body plan of modern echinoderms and then figure out how each family member was linked to their Cambrian ancestors.They found that only the key or axial part of the body, the food groove -- which funnels food along each of the starfish's arms -- was present in Cantabrigiaster. Everything outside this, the extra-axial body parts, were added later.The authors plan to expand their work in search of early echinoderms. "One thing we hope to answer in the future is why starfish developed their five arms," said Hunter. "It seems to be a stable shape for them to adopt -- but we don't yet know why. We still need to keep searching for the fossil that gives us that particular connection, but by going right back to the early ancestors like Cantabrigiaster we are getting closer to that answer."
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Animals
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119194401.htm
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Amber-encased fossil shines light on evolution of bioluminescent insects
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Trapped in amber for ~100 million years, an exceptionally well-preserved, light-producing beetle sheds light on the diversification of bioluminescent beetles in the Cretaceous period and provides the missing fossil link between fireflies' living relatives.
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With over 3,500 described species, light-producing beetles are the most diverse bioluminescent terrestrial animals. Fireflies, fire beetles, glow-worm beetles and their kin use light to ward off predators, attract mates, and some females even use it to attract unsuspecting males to eat. Historically, despite their diversity, the evolution of bioluminescence in beetles has been poorly understood."Most light-producing beetles are soft-bodied and quite small, and so have a scant fossil record. However, this new fossil, found in amber from northern Myanmar, is exceptionally well-preserved, even the light organ on its abdomen is intact," said Dr. Chenyang Cai, research fellow at the University of Bristol and associate professor at NIGPAS.The presence of a light organ on the abdomen of the male provides direct evidence that that adults of Cretophengodes were capable of producing light, some 100 million years ago."The newly discovered fossil, preserved with life-like fidelity in amber, represents an extinct relative of the fireflies and the living families Rhagophthalmidae and Phengodidae," says Yan-Da Li from the Nanjing Institute of Geology and Palaeontology (NIGP) and Peking University in China.The majority of light-producing beetles fall into the giant superfamily Elateroidea with some 24 thousand known species and thousands more awaiting to be described. The discovery of this beetle, published in the "Elateroidea is one of the most heterogeneous groups of beetles and that has always been very difficult for entomologists to deal with, particularly because important anatomical innovations evolved many times independently in unrelated groups. The discovery of a new extinct elateroid beetle family is significant because it helps shed light on the evolution of these fascinating beetles," says Erik Tihelka from the School of Earth Sciences."We think that light production initially evolved in the beetle's soft and vulnerable larvae as a defensive mechanism to ward off predators. The fossil shows that by the Cretaceous, light production was taken up by the adults as well. It could have than been co-opted to serve other functions such as locating mates," says Robin Kundrata, an expert on elateroid beetles from Palacký University in the Czech Republic.Light producing beetles often have unusual adaptations. One of the most striking ones is that the females often don't look anything like their male counterparts and instead retain many larval features into adulthood."A good example of this is the trilobite beetle, where the females don't look like beetles at all and instead superficially resemble trilobites. This means that females often get overlooked when collecting in the field. We want to focus on these unusual beetles when searching the fossil record in the years to come," said Yan-Da Li.
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Animals
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119194334.htm
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Exploration of toxic Tiger Rattlesnake venom advances use of genetic science techniques
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The Tiger Rattlesnake possesses the simplest, yet most toxic venom of any rattlesnake species, and now new research from a team lead by a University of South Florida biologist can explain the genetics behind the predator's fearsome bite.
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Published in the new edition of "Their work is the most complete characterization of the venom gene-regulatory network to date and its identification of key mechanisms in producing the particularly toxic venom will help scientists explain a wide array of genetic questions."Simple genotypes can produce complex traits," Margres said. "Here, we have shown the opposite is also true -- a complex genotype can produce simple traits."Margres collaborated with colleagues at Clemson University, Florida State University and the University of South Alabama, in the project, which sought to explain whether trait differences are derived from differences in the number of genes, their sequence or how they are regulated. Their work is only the second time a rattlesnake genome has been decoded.An organism's genotype is the set of genes it carries, and its phenotype is all of its observable characteristics, which can be influenced by its genes, the environment in which it lives, and other factors. Evolutionary biologists work to understand how genes influence the variation in phenotype among otherwise similar organisms. In this case, they looked at why different species of rattlesnakes differ in venom composition and toxicity.Tiger Rattlesnakes are native to the Sonoran Desert of southern Arizona and northern Mexico where the relatively small pit viper preys on lizards and rodents. While some species of rattlesnakes have complex venoms that are the result of scores of genes, Margres said the Tiger Rattlesnake's venom is quite simple -- as few as 15 of its 51 toxic-producing genes actively drive the production of proteins and peptides that attacks its prey's nervous system, forces blood pressure to drop and causes blood clotting to cease.The team found that the number of venom genes greatly exceeds the number of proteins produced in the simple phenotype, indicating a complex process was at the heart of the toxic venom and the Tiger Rattlesnakes even has toxic genes to spare."Only about half of the venom genes in the genotype were expressed," Margres said. "To me, the interesting part is why are the non-expressed genes still present? These genes can make functional toxins, they just don't. That needs to be explored further."Beyond understanding this one species of venomous snake, Margres said the research will help advance genetic science by showing the techniques more commonly used on genetic research on mice and fruit flies, organisms that are often used in genetic studies, can also work when applied to less-studied organisms like snakes. The team used genetic sequencing techniques that are common in human genetics research and in doing so, opened the door for scientists to understand the genotype-phenotype relationship in many other organisms.Another potential side benefit of the research, Margres said, is that snake venom is used in medicine for humans to combat stroke and high blood pressure. The more scientists understand about venom, the better medical engineering can apply that knowledge in drug discovery and development.The research was funded by the National Science Foundation and Clemson University.Video:
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Animals
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119114433.htm
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All-purpose dinosaur opening reconstructed
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For the first time ever, a team of scientists, led by the University of Bristol, have described in detail a dinosaur's cloacal or vent -- the all-purpose opening used for defecation, urination and breeding.
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Although most mammals may have different openings for these functions, most vertebrate animals possess a cloaca.Although we know now much about dinosaurs and their appearance as feathered, scaly and horned creatures and even which colours they sported, we have not known anything about how the vent appears.Dr Jakob Vinther from the University of Bristol's School of Earth Sciences, along with colleagues Robert Nicholls, a palaeoartist, and Dr Diane Kelly, an expert on vertebrate penises and copulatory systems from the University of Massachusetts Amherst, have now described the first cloacal vent region from a small Labrador-sized dinosaur called Psittacosaurus, comparing it to vents across modern vertebrate animals living on land.Dr Vinther said: "I noticed the cloaca several years ago after we had reconstructed the colour patterns of this dinosaur using a remarkable fossil on display at the Senckenberg Museum in Germany which clearly preserves its skin and colour patterns."It took a long while before we got around to finish it off because no one has ever cared about comparing the exterior of cloacal openings of living animals, so it was largely unchartered territory."Dr Kelly added: "Indeed, they are pretty non-descript. We found the vent does look different in many different groups of tetrapods, but in most cases it doesn't tell you much about an animal's sex."Those distinguishing features are tucked inside the cloaca, and unfortunately, they're not preserved in this fossil."The cloaca is unique in its appearance but exhibits features reminiscent to living crocodylians such as alligators and crocodiles, which are the closest living relatives to dinosaurs and other birds.The researchers note that the outer margins of the cloaca are highly pigmented with melanin. They argue that this pigmentation provided the vent with a function in display and signalling, similar to living baboons and some breeding salamanders.The authors also speculate that the large, pigmented lobes on either side of the opening could have harboured musky scent glands, as seen in living crocodylians.Birds are one the few vertebrate groups that occasionally exhibit visual signalling with the cloaca, which the scientists now can extend back to the Mesozoic dinosaur ancestors.Robert Nicholls said: "As a palaeoartist, it has been absolutely amazing to have an opportunity to reconstruct one of the last remaining features we didn't know anything about in dinosaurs."Knowing that at least some dinosaurs were signalling to each other gives palaeoartists exciting freedom to speculate on a whole variety of now plausible interactions during dinosaur courtship. It is a game changer!"
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Animals
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119114427.htm
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Obese, snoring mini pigs show how air flows through the throat during sleep apnea
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With a small snout, a short and curled tail, and a big, round stomach, mini pigs are the epitome of cute -- and sometimes, they snore. Now, researchers think these snoring pigs can be used to study obstructive sleep apnea. A study appearing January 19 in the journal
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"These are very fat pigs," says first author Zi-Jun Liu, a research professor and principal investigator in the Department of Orthodontics at the University of Washington.Because sleep apnea -- a common obstruction of the airway that in humans causes someone to repeatedly wake up -- currently has only a few cumbersome or invasive treatments, Liu and colleagues sought to better understand the mechanism behind the disease.They looked at Yucatan mini pigs, two obese and three of normal weight, in part because they're comparable in both airway structure and size to humans. These pigs might be "mini," but they're still 100 pounds at normal weight. The obese pigs are even heavier. "To give some context, normal human body mass index (BMI) range around 25-28, with obesity reached at over 30-35. In pigs, normal BMIs range from 30 to 35, with obesity reached over 50," says Liu.But even more importantly, obesity in mini pigs can actually cause them to get sleep apnea. In other animal models, like rats and rabbits, the researchers either have to make the animal gain weight to have sleep issues, which still wouldn't confirm sleep apnea in the animal, or they block the airway to make unnaturally occurring sleep apnea. "That's the most important finding," says Liu. "This naturally occurring sleep apnea in these Yucatan mini pigs was validated."After sedating the subjects, Liu and colleagues observed multiple episodes of sleep apnea per hour in both obese pigs, while only one of the normal weight pigs displayed episodes. In natural sleep, only the obese mini pigs had sleep apnea episodes -- and had as many as 35 per hour. While the researchers did not witness any episodes of snoring in the normal weight mini pigs, the obese pigs emitted a low, dinosaur-like snoring in both sedated and natural sleep.Liu and colleagues also studied all five mini pigs in an MRI machine while they were in sedated sleep. Sleep apnea is known to be caused by anatomical restrictions of the nose and throat that cause stoppages of airflow, but the dynamics of how air flows through these passages and the mechanisms that cause the airflow to stop are not well understood. The researchers used the MRI scans they took to construct a 3D replica of the pigs' airways, finding that the obese pigs had significantly more narrowing in the throat and that there was a 25% increase in airflow velocity through these narrowest regions.One of the researchers' hypotheses was that the sleep apnea was caused by what's known as "turbulence" in the airway. "You might be familiar with the term turbulence from when you ride an airplane. It's air that's circulated in just the local area, which of course on an airplane causes it to jump up and down," says Liu. In the airways of the pigs, turbulence formation could be caused by a combination of an abrupt change in the shape of the airflow pathway and high airflow velocity -- and the researchers hypothesized that it might be the reason that air stops flowing in sleep apnea. The findings from the pigs, however, showed that was not the case: despite the narrowing of the pharynx and the increase in airflow velocity, the researchers didn't find any turbulence in the pigs' airways.Liu says that conducting this research came with numerous challenges. It required monitoring 150-200 pound obese mini pigs, with all the bells and whistles of human sleep monitoring: devices to monitor the air flow dynamics, the chest and abdomen movements, the brain and muscle activity, oxygen saturation, and more needed to be hooked up to the pigs at all times to get proper data.The researchers add that, while this research showed that mini pigs can provide a naturally occurring animal model to examine sleep apnea and gave a greater understanding to how sleep apnea affects the body, more must be done to find a long-term solution for and mechanisms behind this disease. "Despite our findings, the sleep apnea mechanism is still not quite understood," says Liu. "There are of course anatomic reasons, but the functional reasons behind it are still up for debate."This work was supported by a grant from National Institute of Dental and Craniofacial Research (NIDCR) and the Morell Research Fund for the Summer Research Fellowship (SURF) from University of Washington School of Dentistry.
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Animals
| 2,021 |
January 18, 2021
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https://www.sciencedaily.com/releases/2021/01/210118113117.htm
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New management approach can help avoid species vulnerability or extinction
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More than 3,000 animal species in the world today are considered endangered, with hundreds more categorized as vulnerable. Currently, ecologists don't have reliable tools to predict when a species may become at risk.
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A new paper published in One of the challenges of predicting species at risk is presented when a shift from relative security to vulnerability is that transient risk factors may not be known."A species or an ecosystem may seem perfectly stable when it unpredictably becomes vulnerable, even in the absence of an obvious stressor," said Tessa Francis, lead ecosystem ecologist at the Puget Sound Institute, University of Washington Tacoma, managing director of the Ocean Modeling Forum, University of Washington, and lead author of the paper. "In some cases, modeling interactions between species or ecosystem dynamics can help managers identify potential corrective actions to take before the species or system collapses."Ying-Cheng Lai, a professor of electrical engineering and physics at Arizona State University, focused on the mathematical modeling process of the research."The Mexican gray wolf is an example of an endangered species that is experiencing a population resurgence in some areas, yet remains vulnerable in others," said Lai. "The predator-prey relationship between the Mexican gray wolf and elk, mule, white-tailed deer, pronghorn, javelina, rabbits, and other small mammals is an example of how interspecies relationships can affect endangerment. In a general predator-prey relationship, a significant reduction in the prey population can make the predator endangered."These kinds of interactions, plus other factors such as the species decay rate, migration, the capacity of the habitat, and random disturbances, are included in the mathematical prediction model," Lai continued, "and it turns out that, more common than usually thought, the system evolution dynamics can just be transient. Transients in ecosystems can be good or bad, and we want to develop control strategies to sustain the good ones and eliminate the bad ones," said Lai.Alan Hastings, a theoretical ecologist at UC Davis and an external faculty member at the Santa Fe Institute, notes that "As we apply these mathematical models to understanding systems on realistic, ecologic time scales, we unveil new approaches and ideas for adaptive management."The goal is to develop management strategies to both extend a positive ecosystems as long as possible and to design recovery systems to support resurgence from vulnerable states," said Hastings. "Over time, as successful predictions are incorporated into the mathematical model, the tool will become more accurate."But mathematical models are not a panacea, cautions Dr. Francis. "While models can be useful in playing out 'what ifs' and understanding hypothetical consequences of management interventions, just as important is changing the way we view ecosystems and admitting that things are often less stable than they appear."Additional contributors to the research include: Karen C. Abbott, Case Western Reserve University; Kim Cuddington, University of Waterloo; Gabriel Gellner, University of Guelph; Andrew Morozov, University of Leicester, Russian Academy of Sciences; Sergei Petrovskii: University of Leicester, and Mary Lou Zeeman: Bowdoin College.The team, with sponsorship from the National Institute for Mathematical and Biological Synthesis (NIMBioS) through the University of Tennessee, has been working together as a study group named "NIMBioS Working Group: Long Transients and Ecological Forecasting." The group has produced a number of papers focused on developing mathematical models to understand long transients in ecosystems.
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Animals
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January 15, 2021
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https://www.sciencedaily.com/releases/2021/01/210115110327.htm
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Divergences between scientific and Indigenous and Local Knowledge can be helpful
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Divergences between scientific and Indigenous and Local Knowledge can provide a better understanding of why local pastoralists may be willing, or not, to participate in conservation initiatives for carnivores, a study from University of Helsinki suggests.
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Carnivore conservation has historically been based primarily on scientific knowledge using a wide range of sampling methods, such as camera trapping and track surveys. However, the estimates of these common ecological sampling methods can be quite uncertain and can depend on accessibility and geology, which is the case of many remote areas, such as Sibiloi National Park in Northern Kenya. For this reason, the inclusion of local communities that share land with carnivore species has been encouraged to enhance conservation."I remember at the beginning of the project, many local pastoralists told me that they see cheetahs running at full speed. However, despite their accurate descriptions, I was very sceptical about it, as I did not have any image from my camera traps. A year later, I got a photograph of a cheetah holding a grant gazelle. On that day, I recognized that local pastoralists were correct all along. I acknowledged the importance of complementing scientific knowledge with Indigenous and Local Knowledge of local pastoralists that share their day-by-day lives next to those carnivores," describes Miquel Torrents-Ticó, a PhD student from the Faculty of Biological and Environmental Sciences at the University of Helsinki, and the lead author of the study.Indigenous and Local Knowledge is held by the local community and handed down through generations of continuous interactions with their environment. Traditionally, there has been a tendency to compare Indigenous and Local Knowledge with scientific knowledge looking especially for convergences to enhance wildlife management. However, there are also divergences between scientific and Indigenous and Local Knowledge that have been less studied because they can indicate stakeholders' conflicts and can create challenges in effectively implementing conservation actions."The idea of this study was to complement information derived from camera trapping, track surveys and semi-structured interviews of local pastoralists acknowledging the divergences and explaining the unknown status of carnivores of the remote area of Sibiloi," explains Miquel Torrents-Ticó.Although in the past, Sibiloi National Park in Northern Kenya, had a rich mammalian fauna, nowadays, large animals have decreased sharply. Surprisingly, researchers know very little of this process of biodiversity loss due to Sibiloi' isolated location, and it is not clear which species remain and how threatened they are."Many local Daasanach remember with joy the time when as children they used to see lions, leopards and cheetahs in Sibiloi," says Torrents-Ticó. "However, our study shows a new reality of Sibiloi with some carnivore species already gone, such as lions, and many others present in very low numbers, such as cheetahs and striped hyaenas."In view of these results, the authors call for an urgent need for conservation actions before Sibiloi reaches a dramatic point of no return, where all carnivores will be extinct from the area.This study highlights that carnivores abundances obtained by complementing scientific and Indigenous and Local Knowledge can diverge, which can provide a wider picture of human-carnivores relationships and conservation contexts. For instance, carnivore species that have a high impact on local pastoralists' livelihoods and safety can be perceived as being more abundant by local pastoralists, even if the abundances obtained from ecological scientific methods are low."Divergences between scientific and Indigenous and Local Knowledge due to high perceptions of risk and damage should be considered in order to take into account local pastoralists views, and in this way, make conservation more inclusive," emphasizes Torrents-Ticó.
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Animals
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January 15, 2021
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https://www.sciencedaily.com/releases/2021/01/210115091359.htm
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Snakes evolve a magnetic way to be resistant to venom
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Certain snakes have evolved a unique genetic trick to avoid being eaten by venomous snakes, according to University of Queensland research.
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Associate Professor Bryan Fry from UQ's Toxin Evolution Lab said the technique worked in a manner similar to the way two sides of a magnet repel each other."The target of snake venom neurotoxins is a strongly negatively charged nerve receptor," Dr Fry said."This has caused neurotoxins to evolve with positively charged surfaces, thereby guiding them to the neurological target to produce paralysis."But some snakes have evolved to replace a negatively charged amino acid on their receptor with a positively charged one, meaning the neurotoxin is repelled."It's an inventive genetic mutation and it's been completely missed until now."We've shown this trait has evolved at least 10 times in different species of snakes."The researchers found that the Burmese python -- a slow-moving terrestrial species vulnerable to predation by cobras -- is extremely neurotoxin resistant."Similarly, the South African mole snake, another slow-moving snake vulnerable to cobras, is also extremely resistant," Dr Fry said."But Asian pythons which live in trees as babies, and Australian pythons which do not live alongside neurotoxic snake-eating snake, do not have this resistance."We've long known that some species -- like the mongoose -- are resistant to snake venom through a mutation that physically blocks neurotoxins by having a branch-like structure sticking out of the receptor, but this is the first time the magnet-like effect has been observed.""It has also evolved in venomous snakes to be resistant to their own neurotoxins on at least two occasions."The discovery was made after the establishment of UQ's new $2 million biomolecular interaction facility, the Australian Biomolecular Interaction Facility (ABIF)."There's some incredible technology at the ABIF allowing us to screen thousands of samples a day," Dr Fry said."That facility means we can do the kinds of tests that would have just been science fiction before, they would have been completely impossible."The Australian Biomolecular Interaction Facility (ABIF) was funded through a $1 million Australian Research Council Linkage Infrastructure, Equipment and Facilities (LIEF) grant, with $1 million contributing funding from UQ, Griffith University, Queensland University of Technology, James Cook University, and the University of Sunshine Coast.
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Animals
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January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114095802.htm
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Penned release of green geckos has potential to help preserve threatened native species
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University of Otago researchers have added another piece to the puzzle about how best to translocate New Zealand lizards for conservation purposes -- confine them.
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In a paper just published in the It was the first time such a method had been used with the species and the researchers found it worked well. The geckos' area use decreased over time, indicating territory establishment.Co-author Dr Jo Monks, Otago Honorary Research Fellow and Department of Conservation Science Advisor, says translocations of reptiles and amphibians has, historically and globally, been notoriously unsuccessful. However, recent penned release success of jewelled geckos prompted them to try with a different species."By understanding the behavioural response of barking geckos to a penned release, this research is helping us to understand which techniques best help a new population of geckos establish following translocation to a new site," she says.Barking geckos are one of nine green gecko, moko-k?k?riki, species that only live in Aotearoa New Zealand. They are considered 'At Risk -- Declining' under New Zealand's Threat Classification System due to ongoing predicted declines from habitat destruction and predation by introduced mammals.Many green gecko populations have undergone decline in numbers and locations due to predators, habitat modification, and poaching for illegal trade, but little research on their ecology exists."Protecting barking geckos and other reptiles of Aotearoa is important in its own right and for the mauri of ecosystems in which they have important roles as pollinators and seed dispersers as well as being predators of invertebrates and prey of larger animals," Dr Monks says.There is potential for penned release to work for a wide range of fauna where initial dispersal following translocation could be detrimental to species establishment. It has been done for birds and lizards in Aotearoa.
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Animals
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113144417.htm
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Scientists discover new 'spectacular' bat from West Africa
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A group of scientists led by the American Museum of Natural History and Bat Conservation International have discovered a new species of a striking orange and black bat in a mountain range in West Africa. The species, which the researchers expect is likely critically endangered, underscores the importance of sub-Saharan "sky islands" to bat diversity. The species is described today in the journal
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"In an age of extinction, a discovery like this offers a glimmer of hope," said Winifred Frick, chief scientist at Bat Conservation International and an associate research professor at the University of California, Santa Cruz. "It's a spectacular animal. It has this bright-orange fur, and because it was so distinct, that led us to realize it was not described before. Discovering a new mammal is rare. It has been a dream of mine since I was a child."In 2018, Frick and her colleagues at Bat Conservation International and the University of Maroua in Cameroon were in the Nimba Mountains in Guinea conducting field surveys in natural caves and mining tunnels, known as adits, that were built in the 1970s and 1980s and have since been colonized by bats. In collaboration with the local mining company, Société des Mines de Fer de Guinée (SMFG), the scientists are trying to understand which bat species use which adits and at what times of the year. Of particular interest is Lamotte's roundleaf bat, Hipposideros lamottei, which is listed by the International Union for Conservation of Nature (IUCN) as critically endangered and has only ever been recorded in the Nimba Mountains. Much of its known population lives in the adits, which are in different states of collapse and will disappear in time. While surveying for this bat, the researchers found something peculiar -- a bat that looked nothing like Lamotte's roundleaf bat and did not match the descriptions of any other species that they knew occurred in the area. Later that night, they called on American Museum of Natural History Curator Nancy Simmons, a bat expert and chair of the Museum's Department of Mammalogy, for help."As soon as I looked at it, I agreed that it was something new," said Simmons, the lead author of the paper and Bat Conservation International Board member. "Then began the long path of documentation and gathering all the data needed to show that it's indeed unlike any other known species."Through morphological, mor¬phometric, echolocation, and genetic data, including comparative data from collections at the Museum, the Smithsonian National Museum of Natural History, and the British Museum, the scientists described the new species, which they named Myotis nimbaensis ("from Nimba") in recognition of the mountain range in which it is found. A chain of "African sky islands," the Nimba Mountains have peaks rising between 1,600-1,750 meters (about 1 mile) above sea level and are surrounded by drastically different lowland habitats. As such, they are home to exceptional biodiversity, including bats."In addition to the Lamotte's roundleaf bat, it's possible Myotis nimbaensis could be the second bat species found only in this particular mountain range," said Jon Flanders, Bat Conservation International's director of endangered species interventions.This study is part of an ongoing effort critical in helping the Nimba Mountain bats survive. Bat Conservation International and SMFG have already started working together to build new tunnels, reinforced to last for centuries and in habitat away from the mining project, for the Lamotte's roundleaf bat. And although little is known yet about the population and range of Myotis nimbaensis, efforts like this will likely help it as well.Further information:
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Animals
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113120742.htm
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Asian butterfly mimics other species to defend against predators
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Many animal and insect species use Batesian mimicry -- mimicking a poisonous species -- as a defense against predators. The common palmfly
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David Lohman, an epidemiologist with The Graduate Center, CUNY and tThe City College of New York, and his collaborators studied the genome of 45 samples representing 18 butterfly subspecies across Asia to determine their evolutionary history and establish which genes are responsible for the color variation in females. They found that neither the orange nor brown females had a common recent ancestor. Their study appears in the journal Proceedings of the Royal Society B."The conventional wisdom is that once something evolves and you lose it, it's hard to re-evolve it," said Lohman. "That suggests something is acting like a switch, switching the gene on or off."The researchers found two DNA nucleotides on the The "Evolution of a phenotype can be more plastic than we thought," said Shen-Horn Yen, one of Lohman's collaborators from the Department of Biological Sciences, National Sun Yat-Sen University, Taiwan.To Lohman, studying
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Animals
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113120723.htm
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Researchers uncover viral small RNAs in mosquito cells
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Researchers from Boston University School of Medicine (BUSM) provide a new genomics resource that details the small RNA transcriptomes (gene expression) of four bio-medically important mosquito species.
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This is the first study to provide a platform for biologists to compare the characteristics of these small RNAs between these four mosquitoes as well as the most widely used insects for genetic experiments, the fruit fly, Drosophila. Although previous studies looked at each of the individual mosquito species separately, this study is the first to allow comparisons between all four species."Although mosquitoes are related to Drosophila, they have very different genomes. In addition, mosquitos bite humans for blood meals that allow them to reproduce and but unfortunately allows serious human pathogens like viruses to infect us and cause diseases like yellow fever virus, dengue fever virus, zika virus and eastern equine encephalitis virus," explained corresponding author Nelson Lau, PhD, associate professor of biochemistry at Boston University School of Medicine (BUSM).The researchers obtained cell cultures and dissected samples of the mosquito species Anopheles gambiae, Culex quinquefasciatus, Aedes aegypti and Aedes albopictus. They extracted and purified the small RNA molecules, created libraries for high-throughput sequencing, and then developed a special bioinformatics platform to provide thorough genomic analysis of these small RNAs. They provide all this analysis in a database website for the public to access at The four mosquito species have global impacts on human health. Anopheles is the major vector for the parasite causing malaria, but is not known to transmit many viruses. In contrast, Culex and Aedes mosquitoes are well known to pass viruses between humans during mosquito bites, but it is still unknown why there is this difference between mosquito species for this capacity to spread viruses.According to the researchers this study will allow for better biochemical studies in mosquito cells. "If we can find weaknesses in the small RNA pathways of mosquitoes to make them more intolerant of viruses, perhaps they won't be so able to pass the virus from biting one human to the next human victim."This study was a collaboration between the Lau lab in the Department of Biochemistry and the John Connor and Tonya Colpitts labs of the BU National Emerging Infectious Disease Laboratory (NEIDL) as well as many other mosquito biologists in the USA and the United Kingdom.The findings appear online in the journal
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Animals
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113100822.htm
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Bacteria carried by mosquitoes may protect them against pesticides
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A common bacterial species naturally infecting mosquitoes may actually be protecting them against specific mosquito pesticides, a study has found.
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Wolbachia -- a bacterium that occurs naturally and spreads between insects -- has become more frequently used in recent years as a means of controlling mosquito populations.Scientists at the University of Reading, and the INBIOTEC-CONICET and the National University of San Juan in Argentina, studied the effect of Wolbachia on a common mosquito species and found those carrying the bacteria were less susceptible to widely used pesticides.Dr Alejandra Perotti, an Associate Professor in invertebrate biology at the University of Reading, and a co-author of the study, said: "This shows the importance of looking more closely at how bacteria in mosquitoes and pesticides interact, especially at a time when new plans are being formulated for which methods to use, where to use them and which species to target."Mosquitoes transmit several diseases like dengue fever, malaria, zika and yellow fever to humans through their bites, and collectively kill more than a million people worldwide every year.In the new study, published in This is one of the most widespread species in countries with hotter climates. The mosquito species transmits several diseases, a wide range of viruses such as the West Nile Virus (WNV), the San Luis Encephalitis Virus (SLEV) and the Venezuelan Equine Encephalitis Virus, and in addition a variety of parasites (filarial worms) in Central and South America, Africa and Asia.The team found that the mosquito larvae naturally infected by an Argentinian native strain of Wolbachia were less susceptible to three bacterial pesticides (Bacillus thuringiensis israelensis, Bacillus wiedmannii biovar thuringiensis, and Lysinibacillus sphaericus), two of which are commercially available and used in many countries to control mosquito populations.
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Animals
| 2,021 |
January 12, 2021
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https://www.sciencedaily.com/releases/2021/01/210112110120.htm
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Fossils' soft tissues helping to solve puzzle that vexed Darwin
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Remarkably well-preserved fossils are helping scientists unravel a mystery about the origins of early animals that puzzled Charles Darwin.
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Analysis of the 547 million-year-old remains has enabled researchers to trace the ancestry of some of the world's earliest animals further back than ever before.Their study has uncovered the first known link between animals that evolved during the so-called Cambrian Explosion some 540 million-years-ago and one of their early ancestors.Until recently, little was known about the origins of animals that evolved during the Cambrian event because of a lack of well-preserved fossil evidence.The mysterious origins of animals that evolved at this time -- when the diversity of life on Earth increased rapidly, giving rise to almost all modern-day animal groups -- baffled 19th century naturalist Charles Darwin. It is often referred to as Darwin's dilemma.Prior to the new study, it had proven difficult to trace links with earlier animals because their soft tissues -- which provide vital clues about the animals' ancestry -- almost always break down over time.During fieldwork in Namibia, scientists from the University of Edinburgh unearthed the fossil remains of tiny animals -- known as Namacalathus -- that resemble a pin cushion attached to a short stalk.Using an x-ray imaging technique, the team found some of the animals' soft tissues immaculately preserved inside the fossils by a metallic mineral called pyrite. Until now, scientists had only ever identified skeletal remains of Namacalathus.Studying the soft tissues -- and comparing them with those in animals that evolved later -- revealed that Namacalathus was an early ancestor of species that appeared during the Cambrian Explosion. Among them are types of prehistoric worms and molluscs.The study, published in the journal Professor Rachel Wood, of the University of Edinburgh's School of GeoSciences, said: "These are exceptional fossils, which give us a glimpse into the biological affinity of some of the oldest animals."They help us trace the roots of the Cambrian Explosion and the origin of modern animal groups. Such preservation opens up many new avenues of research into the history of life which was previously not possible."
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Animals
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111190104.htm
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Levels of stress hormone in saliva of newborn deer fawns may predict mortality
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The first-ever study of the levels of the stress hormone cortisol in the saliva of newborn white-tailed deer fawns yielded thought-provoking results that have Penn State researchers suggesting predation is not the only thing in the wild killing fawns.
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"We think the hormone offers a way to evaluate factors in the environment that affect fawns, such as disease, but are difficult to evaluate when just looking at a carcass that has been picked over by predators," said researcher Duane Diefenbach, adjunct professor of wildlife ecology. "By then, it's impossible to be certain what truly caused the fawn's demise."Diefenbach, leader of Penn State's Pennsylvania Cooperative Fish and Wildlife Research Unit in the College of Agricultural Sciences, has a unique perspective on fawn mortality and the impact of predators. In 2000 and again in 2015, he led studies of fawn mortality in Pennsylvania. Both of those research projects included an assessment of predator effects on fawns in the state.In the cortisol study, led by Tess Gingery, a research technologist in the Department of Ecosystem Science and Management, salivary cortisol concentrations in 19 newborn fawns were evaluated in May and June 2017. Saliva was actually collected from 34 newborn fawns in two study areas, but some samples had to be discarded in the lab for insufficient quantity or poor quality.To facilitate capture of those fawns, from January to April of that year, the Pennsylvania Game Commission captured pregnant adult female deer using rocket nets and single-gate traps and inserted vaginal implant transmitters. Those devices -- often referred to as VITs -- notified researchers when and where the does gave birth.Several hours after getting a signal, a crew would scramble to find and process the fawn. The cortisol measuring was just some of the data collected before it was released unharmed to its mother, that lingered nearby. It was important to collect the saliva quickly, however, Gingery explained."We know from research performed on adult deer at another university that it takes 20 minutes from the moment the stress hormone cortisol is released from the brain into the body that it shows up in their saliva," she said. "We needed to measure the fawn's 'baseline' cortisol levels, before the stress from capture and being handled kicked in. So, we sopped up saliva with swabs as soon as we could."While still in the field, researchers separated the saliva from swabs in portable centrifuges and froze the samples for transport to Penn State for analysis.There is a lot of evidence that suggests cortisol can be bad for an individual's survival, body condition, brain development and immune system, Gingery pointed out. Researchers hypothesized that high cortisol concentrations would be bad for newborn fawns' survival, and the data supported their prediction."Fawns that had higher cortisol concentrations in their saliva had lower survival, but we don't know if the high cortisol concentrations caused higher mortality or not," Gingery said. "It could be that elevated stress hormones reflect a fawn's experience with stressful situations rather than causing fawn mortality. For example, a fawn may be starving, which can elevate stress hormone levels, and the lack of food kills the fawn rather than the elevated stress hormone levels."The research findings, recently published in "This research could explain why Delaware -- which has zero predators -- found similar fawn-survival rates to Pennsylvania in a recent study," he said. "Factors other than predation, such as physiological responses like the cortisol we measured, may influence mortality more than predation. As such, the heavy focus on predation in fawn research may be misguided."This research was supported by the U.S. Geological Survey, the Pennsylvania Game Commission and Penn State's Cooperative Fish and Wildlife Research Unit.
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Animals
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