Found 229 Resources containing: Lemur
Giant lemurs went extinct at some point in the last 2,000 years—but in a newly-discovered “lemur graveyard," they're still a jaw-dropping presence. A team of divers found hundreds of giant lemur skeletons—along with fossils from other extinct species—in an underwater cave deep beneath a Madagascar national park.
Scientists think that the giant lemurs found in the cave washed in over time, National Geographic reports. There, they decomposed in a relatively peaceful environment that left the skeletons marvelously intact. Because the skeletons are so well-preserved, they offer an “unprecedented look” at a species—lemurs so huge, they are being compared to gorillas.
Scientists hope to use the information yielded by the giant lemur cache to shed new light on the now-extinct species. It is estimated that there were up to 50 species of lemur living on Madagascar when the island became populated by humans, but only 33 survive. And while some believe humans hunted giant lemurs into oblivion, recent research on their DNA suggests a small population size may have been to blame—which means the underwater find is even more precious to researchers.
And the lemur bones represent only one find in the underwater graveyard. Scientists also uncovered the bones of an extinct elephant bird and representatives of a long list of other species, from rodents to ancient crocodiles. They believe even more skeletons might be buried under the sea floor. Alfred Rosenberger, an anthropologist and archaeologist who led the international team of cave divers and paleontologists, said in a release that the project is only just getting started:
This is the success of just phase one.…[The discovery is] the beginning of a complex international project that has a lot of long, hard work in store.
The human-driven extinction of fruit-eating lemurs on Madagascar has created multiple "orphan" plant species with precarious futures because their primary seed dispersers are gone, scientists say.
The findings, detailed in this week's issue of the journal of the Proceedings of the National Academy of Sciences, could have implications for conservation efforts not only in Madagascar, but around the world.
Among the world’s most unique primates, lemurs play a vital role in Madagascar as seed dispersers for many plants and are essential for maintaining healthy and diverse forests on the island. Fruits make up a large part of many lemurs' diets, and the animals will often ingest whole seeds and then poop them out far from the parent tree, thus helping the plants spread.
"In other tropical areas, the primary seed dispersers are birds, but in Madagascar, that's not the case," says study first-author Sarah Federman, a graduate student at Yale University. "The burden of seed dispersal falls mainly on lemurs, of which there are very few."The researchers examined lemur features, like the skull of this mouse lemur, to identify what seeds the primates may have had a role in dispersing. (Courtesy Sarah Federman)
That number is dwindling even further. Scientists estimate that in the past few thousand years, at least 17 lemur species on Madagascar have been driven to extinction by human activity, through either direct hunting or loss of habitat.
To investigate how these extinctions have affected Madagascar's forests, Federman and her team matched the diets of extinct lemurs with the seeds of plants on the island, including some plant species that scientists suspected were “orphans”--plants that did not have any existing animal seed dispersers.
To infer whether the extinct lemurs were capable of eating and dispersing the seeds, the group analyzed the animals' gape sizes–how wide their jaws could open–as well as other clues, such as their tooth shapes and dental wear.
The scientists concluded that many of the extinct lemur species they examined had once indeed been seed dispersers. Furthermore, one large extinct lemur in particular, called Pachylemur, was likely the primary disperser for a group of orphan plants on the island called Canarium. More than 30 Canarium tree species are found on Madagascar, and the largest of these have seeds that resemble large olives and are too big for Madagascar's existing lemurs to eat.
Bereft of their main seed dispersers, today's Canariums must rely on less-effective secondary dispersers such as strong winds and rodents to spread their seeds, but their days could be numbered, Federman and her team concluded.A golden-crowned sifaka, one of Madagascar's rarest lemurs. (Courtesy Sarah Federman)
The group also identified living lemur species–including several endangered species–that occupy essential dispersal niches. If these lemurs also disappear, the scientists warn, the health and diversity of Madagascar’s forests could be jeopardized.
Mauro Galetti, an ecologist at Paulo State University in Brazil, says the new findings foreshadow what could happen in many other regions, such as continental Africa, Asia and South America, as large fruit-eating animals such as elephants, gorillas, and rhinos are driven to extinction.
"More and more we find evidence for the importance of large frugivores [(fruit-eaters)]to our planet," says Galetti, who was not involved in the study.
Federman says her group's findings have practical and even philosophical ramifications for species conservation.
"Traditionally, conservation tended to be species-specific ... but now people are moving toward more ecosystem-level projects because we’ve realized that you can't protect a species in a vacuum," she says. "Our analysis facilitates thinking about how Madagascar’s lemurs fit into their ecosystems, but it also raises the question of what do you do with a tree that can no longer disperse its seeds. Do we intervene? Or do we just let it go extinct?"
It sounds like something out of a crime show: police pouring through data from surveillance cameras, using facial recognition software to nab the perp. But now, researchers have adapted this software for use in the forests of Madagascar, identifying and tracking the whereabouts of endangered lemurs.
As the BBC reports, the software, known as LemurFaceID, allows scientists to more effectively track and protect the primates. The software can distinguish individual lemurs from digital photographs with greater than 97-percent accuracy. Researchers hope the tool will improve conservation of the species while providing a more humane, noninvasive way to identify individual lemurs. The team recently published their work in the journal BioMed Central Zoology.
To track lemurs, scientists traditionally trapped and tagged individual animals. They cataloged their physical characteristics—body size, markings, notable scars or injuries. But tracking these lemurs as their appearance changes over time is both time consuming and challenging, hampering long-term studies.
“[We] weren’t particularly satisfied with the common approaches used in lemur research,” Rachel Jacobs, a co-author on the paper, tells the BBC. “[S]o we aimed to do something different with red-bellied lemurs, and we sought the expertise of our computer science collaborators.”
To develop the software, Jacobs, a biological anthropologist from George Washington University, turned Anil Jain, a biometrics expert and distinguished professor at Michigan State University.
Jain and his students in the computer science department created a dataset comprising 462 images of 80 red-bellied lemurs primarily taken in Ranomafana National Park in Madagascar. The researchers also included an additional 190 images of other lemur species to help expand the software’s capacity. To identify an individual, LemurFaceID first identifies its eyes and then analyzes the characteristics of each surrounding pixel in the image.
“Like humans, lemurs have unique facial characteristics that can be recognized by this system,” Jain tells MSU Today.
The new software will give lemur researchers and conservationists a new tool for tracking lemurs over time. Long-term data provides researchers with crucial metrics to measure population growth and decline, like the rates of infant and juvenile mortality.
The software could also aid in the fight against illegal captures of the big-eyed primates. With only a clear digital image, locals and tourists can report sightings to law enforcement and researchers to quickly identify captive lemurs.
The researchers believe LemurFaceID could be adapted to protect other mammals with variable facial and skin patterns as well. Jain tells MSU Today that he believes the software could work for bears, red pandas, raccoons and sloths.
The National Zoological Park’s 23-year-old male red-ruffed lemur, Joven, enjoys a tasty St. Patrick’s Day frozen treat made of apples, pears, cucumbers, honeydew and diluted […]
The post A St. Partick’s Day treat for the Zoo’s red-ruffed lemur appeared first on Smithsonian Insider.
Subjects watched demonstrators for varying amounts of time. When given the pipe, each of the subjects in both groups opened the door on their first attempt using the method they had seen demonstrated.
The post Lemurs exhibit ability for social learning in zoo experiment appeared first on Smithsonian Insider.
Structural characterization of neutral and acidic oligosaccharides in the milks of strepsirrhine primates: greater galago, aye-aye, Coquerel's sifaka and mongoose lemur
With their small furry bodies and large inquisitive eyes, gray mouse lemurs can seem like a cross between a pug and an alien. In fact, these Madagascar primates share much in common with us. For one, they feel mounting stress as their forest habitat is destroyed—and new research shows how living under constant pressure can hurt their survival.
Mouse lemurs are a subgroup of lemurs that boast the title of smallest primates on Earth. The gray mouse lemur (Microcebus murinus), which measures in at just under a foot from nose to tail and weighs around two ounces, is the largest species within that group. It's currently considered to be a species of "Least Concern" by the International Union for Conservation of Nature's "Red List," but the organization does note that the population of gray mouse lemurs is declining due largely to habitat loss.
Overall, Madagascar's dozens of lemur species have long faced threats from deforestation and hunting by humans. "It's well known that this species is under very high pressure from anthropogenic activities and habitat loss," Josué Rakotoniaina, an ecologist at Germany's Georg-August University of Göttingen, says of his choice to scrutinize these petite primates in particular. "But there was no study of how those human activities can affect these animals ecologically."
Mouse lemurs are proving surprisingly useful to scientists studying human diseases, thanks to their conveniently small size (about double the size of a mouse, with a tail up to twice the length of their body) and genetic similarity to us (they’re primates, like us and unlike mice). In recent years, scientists have found that they make the perfect model for looking at obesity, eye disease and even neurological disorders like Alzheimer’s disease and dementia.
Rakotoniaina wanted to see how the stress that environmental pressures caused in these lemurs impacted the animals, particularly when it came to their survival and reproduction. Prior research has shown that the hormones released when a person or non-human animal undergoes stress are useful in the short-term for fighting or fleeing from threats, whether from a predator or a street brawl, but physiologically harmful when experienced for long periods. (To be clear, the researchers used “stress” to mean the body’s response to any kind of situation causing hardship, whether it be fear, lack of food or shelter or inability to find a mate.)
Hormones like cortisol—a steroid found in the blood, saliva, urine, hair and feces of humans and other animals—are often measured by ecologists as a proxy for the health of a group of organisms. But samples from blood or urine capture only the stress levels at a certain point in time for that animal, making it difficult to draw conclusions about the dangerous long-term stress that organism is facing. To get around that issue, Rakotoniaina turned to something most mammals have in abundance: hair.
Hair has many remarkable qualities. For one, as it slowly grows, it preserves traces of an animal’s condition and environment in a timeline that scientists can later interpret, not unlike tree rings or sediment or ice cores. By taking samples of hair from wild gray mouse lemurs that were trapped and released, ecologists can see how the lemurs' cortisol levels have changed over the course of time that those hairs grew, giving a much more complete picture of the long-term stress faced by the animal.
With data from colleagues at the German Primate Center, Rakotoniaina was able to obtain hair samples and keep track of a population of 171 gray mouse lemurs in Madagascar's Kirindy Forest for two years starting in 2012. By connecting the measured cortisol levels to how the lemurs fared during those years, Rakotoniaina and his colleagues found that lemurs showing lower levels of cortisol had an average chance of survival that was 13.9 percent higher than the lemurs with higher cortisol levels, according to their research published today in the journal BMC Ecology.
Though the study did not try to figure out exactly how the stress levels make the lemurs less likely to survive, Rakotoniaina speculates that it could be due to a variety of factors, including stressed lemurs being more vulnerable to disease from weakened immune systems, and less able to react effectively in various life situations that come with normal stress.
For example, a part of the study tracked 48 lemurs during their mating season and found that the stressed lemurs, particularly male ones, had higher chances of dying than the overall average. This was likely because they could not handle the additional stresses of mating on top of survival. Rakotoniaina and his colleagues are planning next to figure out how exactly the stress is hurting these lemurs by more closely tracking their health over time.
With these results, Rakotoniaina sees great use for easily obtained and non-invasive hair samples in studying the health and population dynamics of other mammals or lemur species.
"It's a really huge advance in this field," Rakotoniaina says, noting that this method could be used by conservationists as an accurate barometer for monitoring the animals their tracking and whether their conservation methods are working effectively.
Michael Romero, a biologist at Tufts University who researches stress physiology, says there haven't been many studies trying to link an animal's response to stress to its survival, and those that have been done haven't had consistent results.
The study "is an exciting addition to the work on the role of the stress response in helping wild animals survive in their natural habitats," says Romero, who wasn't involved in the study. He sees the new research as a step toward understanding how specific stressful events, especially those caused by humans, can impact an animal's life.
However, Romero does caution that the response to stress that Rakotoniaina's study measured is relatively small. "Whether such a small effect will be a reliable marker is still an open question," he says.
Madagascar is home to many unique and threatened mammals, such as lemurs and small hedgehog-like creatures called tenrecs. Most people wouldn’t think of consuming one of these animals, but for many in Madagascar, bushmeat is on the menu. Scientists assumed that people turned to wild meat just to survive, but two new studies that examine the entire supply chain for this meat have found that consumption of wild mammals in Madagascar is common and far more open a practice than anyone had suspected.
“One of the issues that’s maybe stymied progress [in thwarting the bushmeat trade] is that it always felt like there was a fight between: Are they people starving? Or are they just rich and they want to eat bushmeat as a luxury good?” says the studies’ lead author Kim Reuter, a biologist previously of Temple University and now at Conservation International in Nairobi. “But I want people to see that the reality is less homogenous, in that these are normal people” eating these animals.
In many cases, ordinary people are buying wild meat when they have some extra money, and the commercial part of the bushmeat trade is out in the open and easy to find, Reuter and her colleagues report in PLOS One and an upcoming paper in Environmental Conservation.A cook prepares wild bat for a restaurant in Madagascar. (Kim Reuter)
Reuter and her colleagues interviewed people in cities and rural towns across northern Madagascar, including in the capital, Antananarivo, in May through August 2013. At every fifth house, the scientists knocked and asked the head of the household about their meat preferences and meat consumption during the last three days, as well as over their lifetime.
The study area covered a cross-section of northern Madagascar, ranging from urban to rural and including many ethnic and religious groups. Some 83 percent of those surveyed said they held taboos against eating certain kinds of meat. These taboos varied by religion, tribe, family and region. Muslims, for example, are not supposed to eat any forest animals, including bushmeat. And families often have taboos against eating specific animals, such as lemurs or tenrecs, which some believe to be associated with bad agricultural harvests.
Reuter’s team heard other reasons for avoiding bushmeat, as well. “We're in this village in the middle of nowhere,” she recalls, “and this old guy would just tell us, ‘Oh, I don’t eat any lemurs anymore. It’s bad for my cholesterol.’”
Still, 78 percent of people surveyed had eaten wild meat in their lifetimes, and 31 percent had eaten it in the previous six to eight months.
Those surveyed gave different reasons for eating different mammals. For example, they often ate carnivores like the cat-like fossa because the animals ate human food or were threatening farm animals. Lemurs and tenrecs tended to be consumed for subsistence, in contrast, and bats and wild pig were eaten when people had income to spend.
A smaller study, from 2014, had estimated that 98 percent of wild meat in Madagascar was obtained informally, through hunting, bartering or gifting. But Reuter’s team found that in rural areas, about 30 percent of the bat and lemur meat was purchased. And urban residents, their survey showed, purchased 56 percent of the bat meat they ate and 62 percent of their wild pig meat in markets or restaurants. The commercial trade in urban areas was concentrated in a few well-known market stalls and restaurants. Reuter also saw packaged, frozen wild pig available in some supermarkets.In Madagascar, some market stalls openly sell bushmeat, such as wild pig. (Haley Randell)
These markets and restaurants were not hard to find. “Once we started asking,” says Reuter, “everyone was like, ‘Of course, that place down the street, didn’t you know?’” She had even eaten at one restaurant without noticing that bushmeat was on the menu.
“This type of comprehensive study is really important,” says Drew Cronin, a conservation biologist at Drexel University who studies the bushmeat market in Equatorial Guinea in Africa. “It's hard to target conservation planning unless you've been out there and have the on-the-ground knowledge.”
This new trove of information about wild meat eating suggests that better enforcement of the law help to conserve the rare fauna of Madagascar, says Reuter. Hunting is currently limited by law, but she says none of the hunters she met had a permit to hunt because rules are overly complex and not well-communicated. Outlawing all hunting wouldn’t be a great option, however, because some people do need bushmeat to survive, she says. Conservation efforts might be better spent on targeting the commercial trade in bushmeat at markets and restaurants.
In addition, says Cronin, “Education and outreach is pretty much always positive. The only drawback is, it's a long game.”
During her research, Reuter also noticed that some bat, wild pig and tenrec meat was priced high enough that it’s probably aimed at the tourist market. She suggests educating tourists and adopting a voluntary labeling scheme for meat that has been obtained legally, such as from wild pigs that threatened livestock.
“I believe that if we don’t act on this now,” she says, “it doesn’t matter what research we do. There won’t be much bushmeat left in 10 years to study.”