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Wild Inside the National Zoo: Primate Parenthood

Smithsonian Channel
Red-ruffed lemur Molly and Allen's swamp monkey Layla are both first-time mothers. Join caretakers at Smithsonian's National Zoo as they introduce us to their adorable newborns and show us how each parent is handling her new role. From: WILD INSIDE THE NATIONAL ZOO: Primate Parenthood

Why This Elephant in India Is Blowing Smoke

Smithsonian Magazine

It’s not unheard of for animals to learn to smoke—there’s a chimp at a North Korean zoo famous for lighting up and earlier this month an orangutan in Indonesia was caught expertly smoking a cigarette. But another animal that appears to be smoking is a head scratcher; Jeanna Bryner at LiveScience reports that biologists in India recently recorded an Asian elephant blowing out puffs of what appears to be smoke in the middle of the forest.

The puffing pachyderm was found by Vinay Kumar, Assistant Director of the Wildlife Conservation Society’s India Program while he and his colleagues were out checking camera traps in Nagarahole National Park and Tiger Reserve in the state of Karnataka. In the video, the elephant appears to pick up and stuff chunks of charcoal into her mouth before exhaling a plume of what looks like smoke. “In India, the Forest Department burns fire lines to create fire breaks that can help control forest fires, Kumar tells Bryner. “And this effort leaves behind wood charcoal on the forest floor.”

According to a press statement from the WCS, researchers aren’t sure exactly what the elephant is doing, but it’s probably not just fooling around. Charcoal is known for its ability to bind with toxins and works as a laxative. So eating the charcoal may serve as a sort of wildlife medicine for the elephant. Charcoal is readily available in most places after forest fires or lightning strikes.

“I believe the elephant may have been trying to ingest wood charcoal,” WCS elephant biologist Varun Goswami says in the statement. “She appeared to be picking up pieces from the forest floor, blowing away the ash that came along with it, and consuming the rest.”

Such animal self-medication using natural materials is called zoopharmacognosy. And it's relatively common in the animal world; anyone who has a cat or dog that ate grass till it barfed has witnessed the phenomenon. But there are more sophisticated examples as well.

Red colobus monkeys on the island of Zanzibar, for instance, have been observed eating charcoal to counteract toxic substances in their diets. In another study, reports Joel Shurkin at PNAS, researchers near Salonga National Park in the Congo witnessed bonobos carefully collecting certain sandpapery leaves and carefully placing them on their tongue, balling them up and swallowing them whole. It’s believed they use the scratchy leaves, which are not a normal part of their diet, as a way of scouring parasites from their systems.

Other examples include red and green macaws that eat clay to kill bacteria and aid digestion, spider monkeys that consume leaves that may improve fertility, lemurs that eat leaves that spur milk production and pregnant elephants in Kenya that munch leaves that may speed up delivery.

While it's not clear how much of this behavior is innate and how much is learned, at least one species shows that animals are aware of chemicals in their environment and their potential uses. House finches in Mexico City figured out that lining their nests with nicotine-laced cigarette butts helps keep out mites, lice and other potential parasites.

Why Some Mammals Kill Babies of Their Own Kind

Smithsonian Magazine

Step inside the mind of a killer. In what may seem like a cruel act in nature, males of certain mammal species are sometimes driven to kill babies of their own species. The main culprit, biologists think, is the species' social structure and reproductive strategy. Looking across hundreds of species, infanticide is more common in mammals when a few males must compete to reproduce with several females.

Across the animal kingdom, infanticide has been observed in totally disparate mammal species, from dolphins to lions to baboons. Since it was first witnessed in the wild, researchers have come up with a variety of explanations as to why males might kill infants of their own species. The newborns could be seen as exploiting or competing for resources. Some experts even suggested that it might be purely pathological, but with a clear gain for the killer (in reproductive success), that theory has largely been kicked to the curb. Most researchers instead agree that “infanticide can be an evolved reproductive strategy in males, and sometimes females as well,” says Sarah Hrdy, an anthropologist at the University of California at Davis, who first proposed the idea in the 1970s.

Still, teasing out the intricacies of why it evolved in some mammals and not others has been tricky. Dieter Lukas, a zoologist at the University of Cambridge, and his colleague Elise Huchard, a behavioral ecologist at the French National Centre for Scientific Research, wanted to see if they could find a common denominator for infanticide and its consequences. They looked at observational studies of 260 species in total—119 that practice infanticide and 141 that don't—and only included observations where the kill was confirmed and the killer was clearly male.

After comparing different factors related to social structure and mating behavior, a pattern emerged. Males committed infanticide more frequently in species where males and females lived together and a few males dominated as mates—but only remained at the top of the pack for brief periods of time. The practice was also associated with non-annual or seasonal reproduction cycles, meaning females could mate whenever. Through infanticide, males can eliminate the offspring of their competition and get the female back to full baby-making capacity faster, the team reports in a study published today in Science.

Image by Elise Huchard. A calmer scene of a Chacma baboon social group. (original image)

Image by Elise Huchard. A mouse lemur (Microcebus murinus) infant in the wild. Mouse lemur females may try to avoid infanticide by mating with multiple males, which comes with other advantages as well. (original image)

Image by Courtesy of Flickr users Marie and Alistair Knock. Lion cubs (Panthera leo), like the one pictured above in Kenya, may be cute, but they can be easy prey for competitive males. (original image)

Image by Courtesy of Flickr user Joachim S. Müller. While male meerkats (Suricata suricatta) don't practice infanticide, but female meerkats are notorious for killing the infants of rivals. (original image)

“Infanticide is probably the most extreme manifestation of sexual conflict in mammals, with a major fitness cost for mothers who lose their offspring, in which they have already invested lots of time and energy,” says Huchard. So females have evolved counter-strategies. One of those strategies might be monogamy, as a study in the Proceedings of the National Academy of Sciences suggested last year. But Lukas and Huchard found that females seem to do just the opposite to prevent a baby’s murder. Across the same swath of species, the researchers examined the frequency of infanticide against testes size. That's a proxy for female promiscuity, because the more promiscuous the females, the more sperm the male needs to ensure mating success. Species with larger testes had evolved infanticidal behavior earlier on in their family tree. A male lion or monkey can’t exactly demand a paternity test, so it makes sense: If a male thinks the baby is his, he’s less likely to kill it.

“Selection for larger testicles, which [the authors] describe in their paper, is a male counter-strategy to that female counter-strategy, which gives you an idea of how dynamic and complicated evolution of reproductive strategies can be,” says Hrdy, who was not affiliated with the study. “We cannot understand what one sex is doing without also taking into account what has been going on in the other.”

Plenty of females commit infanticide, too. Earlier this year, a female sloth bear at the National Zoo shockingly ate two cubs—perhaps because she could sense they were ill. “It may sound harsh, but the strategy is for the mother to favor her own survival and thus have at least a chance of breeding under more favorable circumstances in the future,” explains Leslie Digby, an evolutionary anthropologist at Duke University.

Then there are females who kill the offspring of rivals, probably to give their own kids a better shot at survival with either more resources or more protection from a male father figure. Some females might have a counter-strategy for that as well. Take banded mongooses—subordinate females have their litters on the same day as dominant females. All the newborns live in the same burrow, so the dominant female doesn’t know which kids to kill.

The next step for Lukas and Huchard will be to examine the evolutionary underpinnings of female baby-killers across mammal species. Overall, Lukas adds, the work highlights how social interactions can be powerful drivers of evolution. “Even with something like this very aggressive behavior, if the social circumstances change, the male will not kill the offspring,” he says. “We always think about evolution as adapting to the environment. We sometimes tend to forget how other individuals are actually a massive part of our environment.”

Why People Turn to Lemurs and Other Endangered Animals for Dinner in Madagascar

Smithsonian Magazine

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.”

Why Paleontologists Should Love Meat-Eaters

Smithsonian Magazine

Let's face it: Carnivory isn’t for everyone. (Try taking a vegetarian to a steakhouse if you need further convincing.) But there is one case in which paleontologists agree that chewing flesh is an unassailable good: Meat-eaters helped make our remarkable fossil record.

Consider an unfortunate human known to experts as SK 54. We don’t know whether this young Paranthropus was happily skipping along or grumpily trudging through the veldt just before tragedy struck, but what we do know is that this prehistoric human became a leopard’s dinner. Two rounded punctures in the 1.5 million year old skull roof mark where a big cat dragged the youngster off by the head, the big cat’s interpretation of getting take-out.

It’d be easy to look at SK 54’s fate as a chilling reminder that humans spent millions of years as prey. Not merely being killed, but more specifically getting eaten, is an enduring fear. But for paleontologists, there’s a deeper lesson here: Far from being an anomaly, SK 54 represents one of many fossils that may never have made it into the fossil record without the hunger-motivated intervention of prehistoric carnivores. By helping themselves to a hot meal, meat eaters assembled a record of our past.

The textbook version of fossilization goes something like this. Alive or dead, an organism needs to be rapidly buried. Sand, mud, ash—almost any sediment will do. This geologic blanket keeps the bones safe from scavengers that would otherwise destroy and scatter the remains. Carnivores are thus cast in the role of natural enemies of paleontologists. But, in truth, fossil hunters owe a debt of gratitude to a variety of prehistoric predators—especially those who preyed on our own predecessors.

Consider the crocodile. Dozens of schlock horror movies have banked on the terror of being snaffled up by the toothy saurians, but the reptilian ambush predators of Olduvai Gorge actually did paleontologists a valuable service.

Back in the days that Homo habilis was wandering around Tanzania, around 1.8 million years ago, Olduvai was a marshland inhabited by huge, horned crocodiles. It’s difficult to say whether these prehistoric giants were able to catch the prehistoric people fresh or scavenged bodies, but a Homo habilis foot and two leg bones bear crocodile bite marks. This led paleontologist Christopher Brochu and colleagues to name the Olduvai predator Crocodylus anthropophagus – the human-eating crocodile. And while such scenes might be unsettling to envision, those crocodiles dragged human remains into an environment where sediment was being laid down and therefore fossilization could take place.

The giant hyenas of China’s Dragon Bone Hill provided a similar service. While Homo erectus – famously known of Peking Man upon discovery – are indeed found in the 750,000 – 200,000 year old sediments of the cave, the most numerous fossils belong to Pachycroctua bervirostris – a stocky hyena as heavy as a lion. This was their turf, and, according to paleoanthropologist Noel Boaz and colleagues, damage to the Homo erectus bones only reinforces the conclusion.

The perforations on this Paranthropus skull cap show where this early human was punctured and dragged by a leopard. Ultimately, the mutilated skull became a valuable addition to the fossil record. (The Natural History Museum / Alamy )

About 67 percent of Homo erectus bones found at the site show signs of gnawing by large carnivores, and the giant hyena in particular. There are some indications that the Homo erectus sometimes used the cave as a refuge, their tools and evidence of fire giving away their efforts to hunker down, but the overwhelming signal was that hyenas were bringing the humans back to their den to consume at their leisure.

It was a grisly process. After finishing the meat of the body, the hyenas likely ate the easily-available muscles on the outside of the skull, Boaz and coauthors proposed, before cracking off the lower jaw to get to the tongue. From there the hyenas may have braced the skulls against the cave floor to break open the cranium to get the fatty brain inside, a delicacy for the carnivores. Yet while we might wish that Pachycrocuta were gentler with our ancient relatives, their efforts nevertheless scattered Homo erectus bones in a place where they could be buried and held safely until discovery. While most of these Homo erectus bones were later lost in transit – an open mystery of Sherlockian proportions – and only survive today as casts of the originals, they were an international sensation when discovered and were among the richest human bonebeds ever found. Thanks, hyenas.

The more paleontologists and anthropologists look at the fossil record, the more it’s apparent that meat-eating animals have helped make the fossil record we now study. Owls and other birds of prey, for example, have kept a long-running record of small mammals in the pellets they deposit, and crocodylians have been unwittingly contributing to the fossil record for over 47 million years. Big cats have had a paw in shaping our view of the past, too. Leopards have been stashing their prey in caves for millions of years, and, even in recent history, cougars have made enough of a habit of stashing kills in hard-to-get places that they can sometimes confuse archaeologists. Even lions, who were thought to almost never accumulate bones, can sometimes stash impressive skeletal assemblages.

Carnivore contributions to the fossil record haven’t stopped. Today, meat-eaters in Africa like hyenas, jackals and big cats are all adding to tomorrow’s fossil record, says says Smithsonian National Museum of Natural History paleoanthropologist Briana. Of these, hyenas are our heroes. The reason why, Pobiner notes, is “mainly feeding their babies in their dens, which can be already underground.” It’s a ready-made situation for future fossilization. They may destroy a fair amount of their meals, to be sure, but better to have leftovers than no future fossils at all.

Our helpful carnivore neighbors have done more than just increase the sample size of hominin remains. They’ve also helped anthropologists put us in our place. Early visions of prehistoric people saw them as exceptionally violent and brutish. The damage on SK 54 and on the Dragon Bone Hill humans were originally interpreted to be signs of murder, and even cannibalism. But realizing that early humans were often prey helped usher in a more nuanced vision of our ancestors. These were people struggling to survive while also learning from the carnivores we feared and competed with.

Once our ancestors stopped cowering in the shadow of predators and stepped into the carnivore guild ourselves, using stone tools to stand in for slicing teeth, they inadvertently started to create a fossilized record of their favorite foodstuffs. The menu has ranged from mammoth to lemurs to seafood, scattered through caves and collected in middens. People creates records of their meals just as carnivores contributed to our own story. Which just goes to show: A hominin’s trash is a paleontologist’s treasure. 

Why Are Lemurs Such Good Climbers?

Smithsonian Channel
Lemurs spend a lot of time in trees, so they've gotten pretty good at climbing them. A caretaker at Smithsonian's National Zoo walks us through their physical adaptations that make this incredible skill possible. #ZooQs From: WILD INSIDE THE NATIONAL ZOO: Primate Parenthood

Where Have the Trees of Guam Gone?

Smithsonian Magazine

Guam Papaya TreeGuam Papaya Tree

Scientists believe the absence of seed-dispersing birds is thinning the forests on the island of Guam. Photo by Isaac Chellman

Visitors to Guam’s forests find them quiet–eerily so: No chirping of birds can be heard overhead. But slithering in the shadows on the ground are snakes, each some six feet long. Brown tree snakes made their debut on Guam, the southernmost island in the Mariana Archipelago, when islanders were rebuilding after World War II. Most likely, they were stowaways in lumber shipments heading north through the Pacific Ocean from New Guinea. They quickly began feasting on the birds and small lizards they discovered in Guam’s dense forests, and–free to slither through the mountainous terrain without predators of their own–they completed an invasion of the island at a pace of one mile per year. By the late 1940s, the forests had largely fallen silent, and now, all of Guam’s native bird species are history.

Last fall, scientists from Rice University and the University of Guam published one of the first studies of the island’s extinct forest birds, which include species such as the Mariana fruit dove, Guam flycatcher and Rufous fantail. They focused on how the absence of birds has caused a spike in the spider population, which is 40 times greater on Guam than nearby islands.

Now, the researchers are turning their attention to the issue of Guam’s thinning forests—a consequence, they also believe, of the bird deficit. This summer they’ll launch a four-year study of 16 tree species, looking at how the loss of birds, which scatter seeds, is affecting tree distribution.

Brown Treesnake

The brown tree snake has obliterated nearly all of Guam’s bird species since it was introduced during World War II. Photo by Isaac Chellman

The study has its roots in an a-ha moment that lead scientist Haldre Rogers recently had while conducting another seed-dispersal study in Guam’s forests. “I noticed that there seemed to be a lot of gaps and that the pioneer tree species–such as papaya and sumak–were difficult to find on Guam, compared to nearby islands,” she explained to Surprising Science. She discovered that there were in fact twice as many such gaps on Guam per unit area of forest. 

Pioneer trees, which are the first to appear after a disruption to the ecosystem and thrive in the full sunlight of open spaces in the forest, have small seeds that are consumed by small birds. “Without birds to move their seeds to these sunny spots in the forest, these quick-growing trees may be less likely to germinate or grow to their full size,” Rogers hypothesized.

The problem with such thinning is that it could change the structure of Guam’s forests. “There’s a concern that may become filled with open areas and start to look more like Swiss cheese than a closed canopy forest,” Rogers said. In other words, what were once cool, dark forests could transform into hot, open sunny ones.

There are other possible explanations for the tree-thinning: An undiscovered forest disease could be targeting pioneer species, or mammals like pigs and deer might have a strong taste for the trees. But according to Rogers, there isn’t strong evidence to support either of these scenarios. The upcoming study will attempt to determine the cause definitively.

Mariana Fruit Dove

The Mariana fruit dove was driven to extinction by the brown tree snake on Guam and is highly endangered on other islands in the Mariana Archipelago. Photo by Isaac Chellman

To that end, the researchers will cut down individual trees in various spots within Guam’s forests, creating new gaps in the forest. They’ll also remove trees from locations on two nearby islands that are still brimming with birds. Then they’ll monitor how long it takes the spaces to fill in and take note of which seedlings thrive on Guam versus on the other islands. It may seem that to get their results they’re destroying what they’re trying to study, but in actuality they’re taking down a tiny percentage of the island’s trees–20 total.

Guam’s situation is similar to that of tropical regions worldwide. “Animals involved in seed-dispersal are in decline in a lot of tropical forests around the world right now,” the co-principal investigator of the study, Amy Dunham, said in a statement. “It’s very important to understand the implications of those declines.” So far scientists have looked into the role of endangered mammals like lemursgiant tortoises (PDF) and African forest elephants (PDF) in seed dispersal, but the upcoming study will be one of the first to focus on endangered birds.

It’s also the rare study to examine what happens when seed dispersal completely ceases–Guam being the only place in the world to experience whole-island forest bird loss in modern times. “The situation on Guam–which is tragic–provides us with a unique opportunity to see what happens when all seed-dispersal services provided by animals are lost from an entire ecosystem,” Dunham said. 

The snakes, meanwhile, continue to dominate the island of Guam. The U.S. Department of Agriculture traps approximately 6,000 brown tree snakes each year, and yet there are still nearly two million slithering around the island. The snakiest patches contain 14,000 of the reptiles per square mile–one of the highest snake concentrations in the world.

In February, the Department of Agriculture embarked on a new tactic for tackling the snake problem: dropping dead mice laced with acetaminophen, which is fatal to them, into the jungle. ”We are taking this to a new phase,” Daniel Vice of the Department of Agriculture’s branch that focuses on wildlife services in Hawaii, Guam and other U.S. held Pacific Islands, said in a recent interview. “There really is no other place in the world with a snake problem like Guam.”

What Does It Mean to Be a Species? Genetics Is Changing the Answer

Smithsonian Magazine

For Charles Darwin, "species" was an undefinable term, "one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other." That hasn't stopped scientists in the 150 years since then from trying, however. When scientists today sit down to study a new form of life, they apply any number of more than 70 definitions of what constitutes a species—and each helps get at a different aspect of what makes organisms distinct.

In a way, this plethora of definitions helps prove Darwin’s point: The idea of a species is ultimately a human construct. With advancing DNA technology, scientists are now able to draw finer and finer lines between what they consider species by looking at the genetic code that defines them. How scientists choose to draw that line depends on whether their subject is an animal or plant; the tools available; and the scientist’s own preference and expertise.

Now, as new species are discovered and old ones thrown out, researchers want to know: How do we define a species today? Let’s look back at the evolution of the concept and how far it’s come.

Perhaps the most classic definition is a group of organisms that can breed with each other to produce fertile offspring, an idea originally set forth in 1942 by evolutionary biologist Ernst Mayr. While elegant in its simplicity, this concept has since come under fire by biologists, who argue that it didn't apply to many organisms, such as single-celled ones that reproduce asexually, or those that have been shown to breed with other distinct organisms to create hybrids.

Alternatives arose quickly. Some biologists championed an ecological definition that assigned species according to the environmental niches they fill (this animal recycles soil nutrients, this predator keeps insects in check). Others asserted that a species was a set of organisms with physical characteristics that were distinct from others (the peacock's fanned tail, the beaks of Darwin's finches).

The discovery of DNA's double helix prompted the creation of yet another definition, one in which scientists could look for minute genetic differences and draw even finer lines denoting species. Based on a 1980 book by biologists Niles Eldredge and Joel Cracraft, under the definition of a phylogenetic species, animal species now can differ by just 2 percent of their DNA to be considered separate. 

"Back in 1996, the world recognized half the number of species of lemur there are today," says Craig Hilton-Taylor, who manages the International Union for the Conservation of Nature's Red List of threatened species. (Today there are more than 100 recognized lemur species.) Advances in genetic technology have given the organization a much more detailed picture of the world's species and their health.

These advances have also renewed debates about what it means to be a species, as ecologists and conservationists discover that many species that once appeared singular are actually multitudes. Smithsonian entomologist John Burns has used DNA technology to distinguish a number of so-called "cryptic species"—organisms that appear physically identical to a members of a certain species, but have significantly different genomes. In a 2004 study, he was able to determine that a species of tropical butterfly identified in 1775 actually encompassed 10 separate species.

In 2010, advanced DNA technology allowed scientists to solve an age-old debate over African elephants. By sequencing the rarer and more complex DNA from the nuclei of elephant cells, instead of the more commonly used mitochondrial DNA, they determined that African elephants actually comprised two separate species that diverged millions of years ago.

"You can no more call African elephants the same species as you can Asian elephants and the mammoth," David Reich, a population geneticist and lead author on the study, told Nature News.

Smithsonian entomology curator W. Donald Duckworth studies a tray of moth specimens in 1975. Taxonomists have traditionally relied on physical characteristics to tease apart species. (Kjell Bloch Sandved / Smithsonian Archives)

In the wake of these and other paradigm-shifting discoveries, Mayr’s original concept is rapidly falling apart. Those two species of African elephants, for instance, kept interbreeding as recently as 500,000 years ago. Another example falls closer to home: Recent analyses of DNA remnants in the genes of modern humans have found that humans and Neanderthals—usually thought of as separate species that diverged roughly 700,000 years agointerbred as recently as 100,000 years ago.

So are these elephants and hominids still separate species?

This isn't just an argument of scientific semantics. Pinpointing an organism's species is critical for any efforts to protect that animal, especially when it comes to government action. A species that gets listed on the U.S. Endangered Species Act, for example, gains protection from any destructive actions from the government and private citizens.These protections would be impossible to enforce without the ability to determine which organisms are part of that endangered species.

At the same time, advances in sequencing techniques and technology are helping today’s scientists better piece together exactly which species are being impacted by which human actions.

"We're capable of recognizing almost any species [now]," says Mary Curtis, a wildlife forensic scientist who leads the genetics team at the U.S. Fish and Wildlife Service's Forensics Laboratory. Her lab is responsible for identifying any animal remains or products that are suspected to have been illegally traded or harvested. Since adopting DNA sequencing techniques more than 20 years ago, the lab has been able to make identifications much more rapidly, and increase the number of species it can reliably recognize by the hundreds.

"A lot of the stuff we get in in genetics has no shape or form," Curtis says. The lab receives slabs of unidentified meat, crafted decorative items or even the stomach contents of other animals. Identifying these unusual items is usually out of the reach of taxonomic experts using body shape, hair identification and other physical characteristics. "We can only do that with DNA," Curtis says.

Still, Curtis, who previously studied fishes, doesn't discount the importance of traditional taxonomists. "A lot of the time we're working together," she says. Experienced taxonomists can often quickly identify recognizable cases, leaving the more expensive DNA sequencing for the situations that really need it.

Not all ecologists are sold on these advances. Some express concerns about "taxonomic inflation," as the number of species identified or reclassified continues to skyrocket. They worry that as scientists draw lines based on the narrow shades of difference that DNA technology enables them to see, the entire concept of a species is being diluted.

"Not everything you can distinguish should be its own species," as German zoologist Andreas Wilting told the Washington Post in 2015. Wilting had proposed condensing tigers into just two subspecies, from the current nine.

Other scientists are concerned about the effects that reclassifying once-distinct species can have on conservation efforts. In 1973, the endangered dusky seaside sparrow, a small bird once found in Florida, missed out on potentially helpful conservation assistance by being reclassified as a subspecies of the much more populous seaside sparrow . Less than two decades later, the dusky seaside sparrow was extinct.

Hilton-Taylor isn’t sure yet when or how the ecological and conservation communities will settle on the idea of a species. But he does expect that DNA technology will have a significant impact on disrupting and reshaping the work of those fields. “Lots of things are changing,” Hilton-Taylor says. “That's the world we're living in.”

This uncertainty is in many ways reflective of the definition of species today too, Hilton-Taylor says. The IUCN draws on the expertise of various different groups and scientists to compile data for its Red List, and some of those groups have embraced broader or narrower concepts of what makes a species, with differing reliance on DNA. “There's such a diversity of scientists out there,” Hilton-Taylor says. “We just have to go with what we have.”

We Burn Just Half the Calories Other Mammals Do

Smithsonian Magazine

Humans and other primates—with the exception of the tiny mouse lemur—have a signficant edge over other large mammals. According to new research, we require half the amount of energy to get through our day as a mammal of equal size. And it's thanks to this energetic advantage that we enjoy such long lives.

It also explains why, while other mammals take just weeks or months to grow up, it takes humans years and years.

A team of scientists studied energy expenditures of 17 primate species in zoos, sanctuaries and in the wild. They measured metabolic rate using an established method called "doubly labeled water," which involves dosing the study subject with a special isotope of oxygen and watching how the creature's system processes it into carbon dioxide over time. After collecting this data from primates, the researchers compared it to known values for other mammals, taken from previously published studies. Controlling for body size, primates burn about 50 percent fewer calories than other animals, they found. 

The team has no idea why primates burn so little energy. "What's more, the difference is not easily explained by differing activity levels: a human would need to run a whole marathon every day to be on an even energetic footing with mammals that aren't primates," the lead author told the New Scientist

Surprisingly, the researchers also found that the primates housed at zoos and sanctuaries burned through the same amount of energy as those in the wild, the New Scientist adds. It's a hint that there might be some energetic sweet spot that our bodies condition themselves to, regardless of what sort of lifestyle we lead.


Watch: The Panda Cub’s Favorite Game Is Belly Flopping Out of Trees

Smithsonian Magazine

At the Smithsonian’s National Zoo, tree-dwelling animals—including lemurs, sloth, monkeys, apes and orangutans swinging from branch to branch—are a common attraction. Visitors were clearly delighted, however, to encounter a giant panda cub climbing a tree before falling to the ground in a majestic belly flop.

Bei Bei, the Zoo’s youngest panda, has captivated viewers since his birth in August 2015, and a new video from the Zoo shows that the cub has no plans of slowing down. In the clip, Bei Bei demonstrates his climbing skills with an added twist: letting go of the tree and tumbling downward with apparent glee.

In a note accompanying the video, the Zoo explains that Bei Bei is making the most of playtime, not just falling with reckless abandon: “#BeiBei has been working on his dismounts out of the trees! Giant pandas are extremely adept climbers and will often climb trees during play sessions, they also are built to withstand falls. It seems like Bei Bei has turned falling into a game.”

Veracia sp

NMNH - Paleobiology Dept.

Veracia sp

NMNH - Paleobiology Dept.

Varecia variegata

NMNH - Vertebrate Zoology - Mammals Division

Varecia variegata

NMNH - Vertebrate Zoology - Mammals Division

Varecia variegata

NMNH - Vertebrate Zoology - Mammals Division

Varecia variegata

NMNH - Vertebrate Zoology - Mammals Division

Varecia variegata

NMNH - Vertebrate Zoology - Mammals Division

Tiny Fossils Reveal the Rise of Mammals on Madagascar

Smithsonian Magazine

Life on Madagascar is unlike life anywhere else in the world. The vast majority of the island’s creatures are only found within its borders, from the lemurs hopping through the trees to the colorful reptiles that clamber through the undergrowth and over stretches of desert.

Islands are often hot spots of biodiversity because isolation is usually an essential ingredient for evolution. Organisms that wind up on islands, separated from their mainland haunts, can become adapted to different habitats than those of their ancestors, much like the many varieties of Darwin’s finches. If the celebrated naturalist had visited Madagascar instead of the Galápagos, “Darwin’s lemurs” might instead be the textbook standard.

But Madagascar has long presented a mystery: The island's fossil record has been nearly blank between about 66 million years ago and 26,000 years ago, leaving biologists to ponder how today's fantastic display of biodiversity came to be after the end of the Age of Dinosaurs.

“Madagascar has some of the most endemic, endangered and bizarre plants and animals on the planet,” says paleontologist Karen Samonds of Northern Illinois University. “Yet we know very little about how they arrived.” Now, thanks to years of backbreaking work and careful sifting of tiny fossils, Samonds and her colleagues are starting to piece together Madagascar’s missing evolutionary tale.

Paleontologists and geologists had previously determined that proto-Madagascar, at the time attached to ancient India, split off from mainland Africa about 135 million years ago. About 88 million years ago, Madagascar and India parted ways, leaving the dinosaurs, mammals, and other creatures there to spin off into strange new forms.

Recent discoveries from rocks dating to about 70 to 66 million years ago include the predatory, knobby-headed Majungasaurus, the armored sauropod Rapetosaurus and the gopher-like early mammal Vintana. After that, the fossil trail picks up again around 26,000 years ago, when enormous lemurs, elephant birds, dwarfed hippos and other now-extinct forms called the island home. But what happened in the long interval in-between? That mystery is what drew Samonds to the island.

“I love the challenge of exploration to remote areas,” Samonds says. “It was clear that finding this ‘missing piece’ in the Cenozoic fossil record had huge potential to answer many different research questions.”

Her team's persistence has been paying off. In 2009, Samonds and her colleagues announced the discovery of a 40-million-year-old sea cow they named Eotheroides lambondrano. This was the first good mammal fossil found in the gap between the reign of the dinosaurs and the late Pleistocene.

The sea cow was uncovered near the little village of Ampazony on the northwestern coast of Madagascar. Not very far away, across the mouth of the Betsiboka River, sits another fossil site that holds even more potential. Its name is Nosy Makamby, and it is just a little spit of land off the coast of the main island.

Previous paleontologists had found fragments of sea cow there at the beginning of the 20th century, but at between 23 and 5 million years old, these were geologically younger than the beast Samonds and her team named. Nosy Makamby looked to hold additional pieces of the Cenozoic puzzle.

The Nosy Makamby site on Madagascar. (Karen Samonds)

During a decade of fieldwork on Nosy Makamby, “the biggest challenge we have is dealing with the ocean tides,” Samonds says. “We camp on the beach, and some of our sites are underwater during certain times of the day.” The team has to carefully coordinate when the island’s fossil-bearing rocks are above the waves.

“A few times we have stubbornly tried to push our window of opportunity and have gotten really stuck”, Samonds says. For instance, after recent cyclones washed away a significant part of the beach, an especially high tide nearly washed out their camp, leading to a waterlogged night. Yet the draw of discovering remnants from an unknown time period keeps the paleontologists going back year after year.

Some of the fossils discovered by the team can be seen with the naked eye. These big bones are prepared for study back in the lab, using tools called airscribes that delicately chip away stone from bone. Not a scrap goes to waste, though. Tiny fossils hide in the mix, and so the matrix chipped off the big bones is left to dissolve in acetic acid and screened through a small sieve. This reveals some of the smaller bones that would have otherwise been missed.

From the fossils recovered so far, it seems that Nosy Makamby was a near-shore marine habitat back in the Miocene, too.

“The most common fossils we discover are animals that live in the ocean near the shore like snails, stingrays, sharks, fish, crocodiles and turtles,” Samonds says. Just last year, the team found more sea cow material, including a lower jaw and possibly another piece of skull. But to Samonds, “the most exciting recent finds are tiny terrestrial animal fossils” that include the teeth and bones of animals such as bats and rodents.

“For each group we find, they fill a gap of knowledge,” Samonds says. Prior to the discovery of Eotheroides, she notes, sea cows were thought to have evolved in the Northern Hemisphere and spread south. But the sea cow from Madagascar in the Southern Hemisphere is so archaic that “it has really turned our perception of sea cow evolution upside down.”

The team has also found fossils of roundleaf bats in the island's Miocene rock, which is not entirely surprising because the animals are found in strata of the same age in many parts of the world. Still, their presence in Madagascar “represents a range expansion, and since they are found in Madagascar today, it helps us bracket their arrival time.”

Each new expedition brings back more fossils and the potential to add a few pieces to the story of how life on Madagascar became so beautiful and strange.

“Since I work in a time period we know virtually nothing about what lived on the island, pretty much everything we find is surprising in some way,” Samonds says. These not only include the beginnings of lineages still alive today, but perhaps even groups of animals that made it to Madagascar but went extinct long before humans arrived.

Samonds is optimistic that she and her team will uncover more of these lost worlds: “We could have some pretty interesting surprises ahead in the fossil record.”

This Leaping Lemur Lady Rules the Bunch (4K)

Smithsonian Channel
Ring-tail lemurs are highly social, extremely adaptable and, like all lemurs, led by a dominant female - and she doesn't put up with any dissent in her ranks, especially in the males. From the Series: Land of Primates: Lemurs of Madagascar

These Feisty Female Lemurs Fight With Babies on Their Backs

Smithsonian Channel
In ring-tailed lemur society, it's the females who call the shots. They live in groups of up to 30 members and the alpha female will fight hard to protect her territory. From the Series: Amazing Monkeys: Conquest of Africa

These Ecologists Borrowed Tricks From Astrophysicists to Count Endangered Orangutans

Smithsonian Magazine

In the last century, orangutan numbers have dropped dramatically. The primate’s total on the island of Borneo is down from roughly 230,000 to about 104,000 individuals, while only 7,500 remain on the Indonesian island of Sumatra.

When it comes to critically endangered species, however, rough estimates aren’t good enough to help ensure their survival. That’s why an unlikely combo of ecologists and astrophysicists has teamed up to use cutting edge drone technology to try and count the animals from the sky.

In a video from WWF UK, primatologist Serge Wich from Liverpool John Moores University explains that counting orangutans is a slow and costly endeavor. Typically, researchers trek through the forest, counting nests and deriving population estimates from their observations.

In their latest project, Wich and astro-ecologist Claire Burke, also of Liverpool John Moores University, tested a new approach. They outfitted a drone with the same type of thermal imaging camera used by astronomers to look at the stars to see if they could spot the heat signatures of orangutans and their nests.

Over the course of six days, the team—which also included members of the WWF and orangutan conservation group HUTAN—conducted 28 10-minute drone flights at the Sepilok Orangutan Rehabilitation Centre and the Kinabatangan Orangutan Conservation Project in the heavily forested Malaysian state of Sabah. In total, the drone crew found 41 orangutans in the trees, all of which were confirmed by observers on the ground. They recently presented their work at the British Ecological Society’s Unifying Tropical Ecology Conference in Edinburgh, Scotland.

Because the tropical forests of Sabah are so hot and humid, the team was uncertain whether the thermal imaging would be able to distinguish between the apes and the background environment at all. Yessenia Funes at Earther reports that the team found the system wasn’t very reliable during the day, but worked well before 9 a.m. and after 7 p.m. when the air temperature is cool enough to differentiate from the apes’ body heat.

Burke tells Funes that previous tries to track tropical animals using thermal cameras just couldn’t get a fine enough resolution to work. The more finely tuned instruments used by astrophysicists, however, were able to give usable pictures.

“In thermal images, animals shine in a similar way to stars and galaxies, so we used techniques from astronomy to detect and distinguish them,” she says in a press release. “We were not sure at all whether this would work, but with the thermal-infrared camera we could see the orangutans quite clearly because of their body heat, even during fog or at night.”

Orangutans weren’t the only species caught on camera. The drones also picked up on a troop of proboscis monkeys and a group of pygmy elephants. In previous tests, the team also used the drone to track Mexican spider monkeys and rabbits in South Africa. Next, they will next try to find critically endangered Lac Alaotra bamboo lemurs in Madagascar. Eventually, they want their thermal drones to keep tabs on all sorts of animals.

“Rhinos, elephants—you name it, we want to do it,” Burke tells Funes.

The goal is to create a system in which an algorithm can identify the thermal fingerprint of individual species. “In the future, we hope to be able to track, distinguish and monitor large numbers of different species of animals in real time, all around the globe, so that this technology can be used to make a real impact on conservation and stop poaching before it happens,” Burke says in the release.

This is not the only way drones are revolutionizing ecology. Drones are being used to collect samples from plumes shot out of whale blowholes; estimate numbers of nesting birds, seals; and turtles and to monitor things like land use change and deforestation.

The Plight of the Right Whale

Smithsonian Magazine

From 800 feet above the Gulf of Saint Lawrence off the coast of Quebec’s Gaspé Peninsula, I peer out of the window of a Twin Otter airplane. The sun glares back from the blue expanse below. In the cabin, a Fisheries and Oceans Canada survey team records sightings of seals, porpoises, dolphins and even basking sharks. Soon we see whales—minkes, fins, humpbacks. The crew is nonchalant. But when a pod of North Atlantic right whales comes into view, the buzz of excitement fills the plane.

The pilot banks to circle, and the crew gathers to one side for a better view. The right whales appear prehistoric, with giant heads covered in callosities—patches of roughened skin unique to each animal. To scoop up copepods, the tiny zooplankton that make up their diet, right whales have gaping mouths and plates of baleen that can reach eight feet long. Their bodies defy all expectations, comically rotund yet strangely elegant as they glide through the sea. Rapt, we watch the huge mammals lunge and dive with a playful innocence that belies the gravity of their situation.

With an estimated 450 individuals remaining, right whales could be functionally extinct in 20 years. Swimming with open mouths, they easily become entangled in the ropes that connect crab and lobster traps to buoys at the surface. As they thrash to free themselves, they often make the entanglement worse. Right whales can drag fishing gear for months before slowly drowning, and collisions with ships also thin their numbers. While reliable data on ship strikes isn’t readily available, necropsies show blunt force trauma as a frequent cause of death.

Image by Nick Hawkins. ‘Callosities’ are patches of roughened skin unique to each whale. Researchers use the patterns to identify individual right whales. (original image)

Image by Nick Hawkins. Aerial view of North Atlantic right whales (Eubalaena glacialis</I>) engaged in a surface active group., with female out front being pursued by males. Known as a "SAG" to researchers, it has a fairly broad definition: two or more whales within a body length interacting at the surface. Typically, the SAG is comprised of one female and a number of males competing with each other to mate with her. Some SAGs are extremely active, with a lot of rolling and white water, whereas others are more sedate. The number of animals in a SAG can range from two or three to more than 40. (original image)

Image by Nick Hawkins. A North Atlantic right whale breaches in the Bay of Fundy, New Brunswick, Canada. With an estimated 450 individuals remaining, the species is among the rarest and most endangered of large whales. (original image)

Image by Nick Hawkins. A right whale named "Lemur" has a significant injury on its tail from the propeller of a large boat. Researchers have also twice observed Lemur entangled in fishing gear. (original image)

It’s not the first time the species has faced an anthropogenic demise. Because they’re slow-moving and float when killed, they were named the ‘right’ whales to hunt. After three centuries of relentless whaling, right whales were reduced to an estimated 60 reproductive individuals by the early 20th century. With protections, their numbers gradually increased, and at the turn of the 21st century, there were just over 500 North Atlantic right whales—nothing near historical abundance, but a recuperating population nonetheless.

More recently, however, things have again taken a turn for the worse. Right whale calving grounds are off the coast of Georgia and Florida. Their annual summer migration takes them up to the Gulf of Maine and Bay of Fundy, where copepods were formerly abundant for the whales to feed on. But climate change is shifting copepod distributions, and right whales have been following their food farther north, up to the Gulf of Saint Lawrence. In this totally new marine environment, the large animals come into conflict with industries unaccustomed to their presence, and the whales are dying at an alarming rate.

Scientists are scrambling to understand these new migration patterns to better protect the whales. The good news is that recent management strategies—like fishing closures and shipping lane changes—show promise of keeping harm out of the whales’ way. While 17 right whales died in 2017, only two have been lost so far this year, neither of them in waters protected by the new measures.

Right whales breaching in the North Atlantic as seen from an aircraft. (Nick Hawkins)

Back in the air, the crew on the Twin Otter immediately radios in their sighting. Their colleagues on the management side need up-to-the-minute information on the locations of the whales. Aerial surveys provide that data, but daily flights are resource intensive, so scientists are developing a new generation of acoustic technologies that can lend a hand. Most intriguing is an autonomous ocean ‘glider’ adapted to monitor whales.

The instrument measures five feet and looks more like a miniature space rocket than a marine vehicle. To cover great swaths of the ocean using little energy, it harnesses some basic science. The glider changes its own density to descend, slowly. Because it has wings, it ‘glides’ forward as it sinks. At a specified depth, it automatically adjusts for positive buoyancy and ascends, still advancing forward. On a single battery, the glider can cruise along at 0.6 mph for up to four months.

The gliders are equipped with hydrophones that use clever software to compare the sounds they hear with an onboard library of whale calls. The computer makes accurate identifications, transmitting real-time whale locations directly to researchers. The hydrophones are also being tested on buoys to listen for passing whales, and because these devices can be deployed for long periods of time, they provide a wealth of data. Persistent and cost-effective, acoustic monitoring technologies will never fully replace aircraft surveys, but they’re an important part of the picture.

Image by Nick Hawkins. Powerless, researchers looked on as whale #3960 tried to wrestle free of crabbing gear, its skin rubbed raw by the ropes. Although the whale eventually freed itself, it will forever bear the marks of its entanglement. (original image)

Image by Nick Hawkins. The unique v-shaped blow of a North Atlantic right whale (Eubalaena glacialis) created by the two nostrils being set at angles to each other. Right whales are the only whale species to exhibit this. (original image)

Image by Nick Hawkins. Right whales congregate in a unique type of behavior called ‘surface active groups.’ Here, a male peers out of the water while trying to slide into position to mate with a female. (original image)

Image by Nick Hawkins. The Ocean Tracking Network (OTN) deploys an autonomous glider off Halifax, Nova Scotia. The gliders provide oceanographic data and record the presence of right whales by listening for their vocalizations. This information helps researchers to understands changing oceanic conditions and whale behaviors. (original image)

Image by Nick Hawkins. Whale watchers observe a group of North Atlantic right whales (Eubalaena glacialis) in the Bay of Fundy, New Brunswick, Canada. (original image)

Closing fishing zones, rerouting ships and imposing speed limits can mitigate risks to right whales, but they don’t eliminate them. And fishing closures in particular have rippling economic effects on communities that rely on crab and lobster.

“Once we saw the presence of whales, we knew that for our fishery to survive, these whales had to thrive,” says Robert Haché of the Acadian Crabbers Association.

Fisheries can reduce their impact by using ropes with reduced breaking strength—sturdy enough to rein in traps but not a struggling whale. However, one innovation promises to revolutionize the industry: ropeless traps. Designs vary, but all allow fishers to deploy and retrieve their traps without leaving ropes in the water column. In one model, a trap is furnished with a spool of rope attached to a buoy on the end. Using an acoustic signal, the fisher triggers a mechanism to release the buoy, which shoots to the surface pulling rope from the spool so the trap can be recovered and checked for crustaceans.

But such designs have yet to achieve widespread use. On a research cruise this summer, Amy Knowlton and her team from the New England Aquarium and Dalhousie University came across whale #3960 trapped in struggle to survive. With ropes wrapped around his head, through his mouth and even between his baleen, the whale flailed in anguish. He struggled to breath, the gear covering his blowhole. “My heart sank,” says Knowlton, who has been studying North Atlantic right whales for 35 years. She thought #3960’s fate was sealed.

Crab gear wreaks havoc on a right whale’s sensitive baleen. Researchers watched helplessly as whale #3960 struggled for hours, finally freeing itself. (Nick Hawkins)

For hours, the crew looked on, helpless, while the whale dove repeatedly in a desperate attempt to free itself of the snare. Then, all of a sudden, it surfaced without the entangling fishing gear and took off at considerable speed. For people on the front lines, it’s the small victories that sustain the fight.

The future of North Atlantic right whales depends on our ability to reduce the impacts of fishing and shipping, Knowlton says. We can save them, she tells me with confidence. Our own innovations have pushed them nearly to extinction, but perhaps new technologies, like acoustic monitoring and ropeless fishing, could help bring these ocean giants back from the brink.

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