Chapter 6. Evolution of the Brain and Behavior
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By Michael Price BOSTON--Among mammals, primates are unique in that certain species have three different types of light-sensitive cone cells in their eyes rather than two. This allows humans and their close relatives to see what we think of as the standard spectrum of color. (Humans with red-green color blindness, of course, see a different spectrum.) The standard explanation for why primates developed trichromacy, as this kind of vision is called, is that it allowed our early ancestors to see colorful ripe fruit more easily against a background of mostly green forest. A particular Old World monkey, the rhesus macaque (pictured), has a genetic distinction that offers a convenient natural test of this hypothesis: a common genetic variation makes some females have three types of cone cells and others have two. Studies with captive macaques has shown that trichromatic females are faster than their dichromatic peers at finding fruit, but attempts to see whether that’s true for wild monkeys has been complicated by the fact that macaques are hard to find, and age and rank also play big roles in determining who eats when. A vision researcher reported today at the annual meeting of AAAS, which publishes Science, that after making more than 20,000 individual observations of 80 different macaques feeding from 30 species of trees on Cayo Santiago, Puerto Rico, she can say with confidence that wild trichromatic female monkeys do indeed appear to locate and eat fruit more quickly than dichromatic ones, lending strong support to the idea that this advantage helped drive the evolution of trichromacy in humans and our relatives. © 2017 American Association for the Advancement of Science.
Elizabeth Eaton A prehistoric marine reptile may have given birth to its young alive. A fossil from South China may be the first evidence of live birth in the animal group Archosauromorpha, scientists report February 14 in Nature Communications. Today Archosauromorpha is represented by birds and crocodiles — which both lay eggs. Whether this fossil really is the first evidence of live birth in Archosauromorpha depends on how another group of semiaquatic animals is classified, says Michael Caldwell, a vertebrate paleontologist with the University of Alberta in Canada. Placement of Choristodera, a now-extinct group that included a freshwater reptile that gave live birth, remains murky, with some researchers putting them with Archosauromorpha and others with a group that includes snakes and lizards. “Our discovery is the first of live birth in reptiles with undoubted archosauromorph affinity,” says Jun Liu, a paleontologist at Hefei University of Technology in China. Researchers have speculated that the biology of archosauromorphs prevented their reproductive traits from evolving, says study coauthor Chris Organ, an evolutionary biologist with Montana State University in Bozeman. This find may disprove that view. “Ancestrally, the science suggests that live birth is not absolutely prohibited,” Organ says. Even though birds and crocodiles haven’t yet evolved to give life birth, this discovery suggests that it’s possible. |© Society for Science & the Public 2000 - 2016
By Virginia Morell Strange as it might seem, not all animals can immediately recognize themselves in a mirror. Great apes, dolphins, Asian elephants, and Eurasian magpies can do this—as can human kids around age 2. Now, some scientists are welcoming another creature to this exclusive club: carefully trained rhesus monkeys. The findings suggest that with time and teaching, other animals can learn how mirrors work, and thus learn to recognize themselves—a key test of cognition. “It’s a really interesting paper because it shows not only what the monkeys can’t do, but what it takes for them to succeed,” says Diana Reiss, a cognitive psychologist at Hunter College in New York City, who has given the test to dolphins and Asian elephants in other experiments. The mirror self-recognition test (MSR) is revered as a means of testing self-awareness. A scientist places a colored, odorless mark on an animal where it can’t see it, usually the head or shoulder. If the animal looks in the mirror and spontaneously rubs the mark, it passes the exam. Successful species are said to understand the concept of “self” versus “other.” But some researchers wonder whether failure is simply a sign that the exam itself is inadequate, perhaps because some animals can’t understand how mirrors work. Some animals—like rhesus monkeys, dogs, and pigs—don’t recognize themselves in mirrors, but can use them to find food. That discrepancy puzzled Mu-ming Poo, a neurobiologist at the Shanghai Institutes for Biological Sciences in China, and one of the study’s authors. “There must be some transition between that simple mirror use and recognizing yourself,” he says. © 2017 American Association for the Advancement of Science.
By Sam Wong Here’s looking at you, squid. Cock-eyed squid have one huge, bulging eye and another normal-sized eye, but the reason has remained a mystery. Now we have an answer. Kate Thomas of Duke University in North Carolina studied 161 videos of the creatures collected over 26 years by remotely operated submarines in Monterey Bay, California. The findings provide the first behavioural evidence that the two eyes are adapted to look in different directions. The large one points upwards to spot prey silhouetted against the sky. The smaller one points downwards to spot bioluminescent organisms against the darkness below. The squid, from the histioteuthid family, live at depths of 200 to 1000 metres, where little light penetrates. The videos show that the squid normally swims with its tail end pointing upwards, but tilted so the large eye is consistently oriented towards the sky. Based on measurements of the eyes and the light levels they would be exposed to, Thomas and her colleagues calculated that having a big upward-pointing eye greatly improves visual perception, while a downward-pointing eye would gain little from being large. “That gives you the context for how this trait might have evolved,” says Thomas. Some of the squid’s prey, such as lanternfish and shrimp, have luminescent undersides so they are camouflaged against the sunlight when seen from below. Yellow pigmentation in the lens of the squid’s large eye may help it distinguish between sunlight and bioluminescence. © Copyright Reed Business Information Ltd.
By STEPH YIN If you’re reading this at home, pause and put on a song you can’t resist dancing to. Go on, bop your head to the beat. Let yourself wiggle a bit. Throw in some arms and legs. If you’re reading this at work, maybe imagine these things at your desk. As you’re dancing, pay attention to where and how you’re moving. How much are you swaying your hips? Are your legs moving together or independently of each other? How vigorously are you moving your torso? You should note those movements, because very specific patterns may make some people appear to be better dancers than others. That’s the conclusion of a study published on Thursday in Scientific Reports, in which researchers asked 200 people to rate 39 female dancers. A few features stood out as contributing to higher-quality dance: big hip swings, and the right and left limbs moving independently of one another (which the researchers describe as asymmetric arm and thigh movements). The researchers speculate that those moves serve two purposes for heterosexual women. “One is, they’re showing off their reproductive quality, perhaps their hormonal status, to males,” said Nick Neave, an associate professor of psychology at Northumbria University in England and an author of the paper. “Another is, they’re showing off how good they are to female rivals.” In 2011, the same researchers reported that women preferred certain dance moves by men, especially exaggerated movements in the upper body. In other studies, Dr. Neave and his colleagues have found links between male dance attractiveness and risk-taking, as well as handgrip strength, a marker for overall body strength. “We know that dance moves are signaling strength and vigor in males,” Dr. Neave said. “Now we’re beginning to do the same research with females.” In the study, his team asked 39 female university students in Britain to dance alone to a drum beat. The researchers used a motion-capture system to track the women’s moves. They animated each dancer as an avatar to try to make sure that only the dance movements — and no other physical features — would affect ratings. Then they recruited 57 men and 143 women to watch 15-second clips of the avatars and rate them each on a numeric scale. © 2017 The New York Times Company
Scientists who spent years listening to the communication calls of one of our closest ape relatives say their eavesdropping has shed light on the origin of human language. Dr Adriano Reis e Lameira from Durham University recorded and analysed almost 5,000 orangutan "kiss squeaks". He found that the animals combined these purse-lipped, "consonant-like" calls to convey different messages. This could be a glimpse of how our ancestors formed the earliest words. The findings are published in the journal Nature Human Behaviour. "Human language is extraordinarily advanced and complex - we can pretty much transmit any information we want into sound," said Dr Reis e Lameira. "So we tend to think that maybe words evolved from some rudimentary precursor to transmit more complex messages. "We were basically using the orangutan vocal behaviour as a time machine - back to a time when our ancestors were using what would become [those precursors] of consonants and vowels." The team studied kiss squeaks in particular because, like many consonants - the /t/, /p/, /k/ sounds - they depend on the action of the lips, tongue and jaw rather than the voice. "Kiss squeaks do not involve vocal fold action, so they're acoustically and articulatory consonant-like," explained Dr Reis e Lameira. In comparison to research into vowel-like primate calls, the scientists explained, the study of consonants in the evolution of language has been more difficult. But as Prof Serge Wich from Liverpool John Moores University, a lead author in the study, said, they are crucial "building blocks" in the evolution of language. "Most human languages have a lot more consonants than vowels," said Prof Wich. "And if we have more building blocks, we have more combinations." © 2017 BBC.
Bruce Bower Hunter-gatherers and farming villagers who live in worlds without lightbulbs or thermostats sleep slightly less at night than smartphone-toting city slickers, researchers say. “Contrary to conventional wisdom, people in societies without electricity do not sleep more than those in industrial societies like ours,” says UCLA psychiatrist and sleep researcher Jerome Siegel, who was not involved in the new research. Different patterns of slumber and wakefulness in each of these groups highlight the flexibility of human sleep — and also point to potential health dangers in how members of Western societies sleep, conclude evolutionary biologist David Samson of Duke University and colleagues. Compared with other primates, human evolution featured a shift toward sleeping more deeply over shorter time periods, providing more time for learning new skills and knowledge as cultures expanded, the researchers propose. Humans also evolved an ability to revise sleep schedules based on daily work schedules and environmental factors such as temperature. Samson’s team describes sleep patterns in 33 East African Hadza hunter-gatherers over a total of 393 days in a paper published online January 7 in the American Journal of Physical Anthropology. The team’s separate report on slumber among 21 rural farmers in Madagascar over 292 days will appear later this year in the American Journal of Human Biology. |© Society for Science & the Public 2000 - 201
By Helen Briggs BBC News The idea that dogs are more intelligent than cats has been called into question. Japanese scientists say cats are as good as dogs at certain memory tests, suggesting they may be just as smart. A study - involving 49 domestic cats - shows felines can recall memories of pleasant experiences, such as eating a favourite snack. Dogs show this type of recollection - a unique memory of a specific event known as episodic memory. Humans often consciously try to reconstruct past events that have taken place in their lives, such as what they ate for breakfast, their first day in a new job or a family wedding. These memories are linked with an individual take on events, so they are unique to that person. Saho Takagi, a psychologist at Kyoto University, said cats, as well as dogs, used memories of a single past experience, which may imply they have episodic memory similar to that of humans. "Episodic memory is viewed as being related to introspective function of the mind; our study may imply a type of consciousness in cats," she told BBC News. "An interesting speculation is that they may enjoy actively recalling memories of their experience like humans." The Japanese team tested 49 domestic cats on their ability to remember which bowl they had already eaten out of and which remained untouched, after a 15-minute interval. © 2017 BBC
By NANCY L. SEGAL and SATOSHI KANAZAWA In 1973, the biologist Robert Trivers and the computer scientist Dan Willard made a striking prediction about parents and their offspring. According to the principles of evolutionary theory, they argued, the male-to-female ratio of offspring should not be 50-50 (as chance would dictate), but rather should vary as a function of how good (or bad) the conditions are in which the parents find themselves. Are the parents’ resources plentiful — or scarce? The Trivers-Willard hypothesis holds that when their conditions are good, parents will have more male offspring: Males with more resources are likely to gain access to more females, thereby increasing the frequency with which their genes (and thus their parents’ genes) are preserved in future generations. Conversely, male offspring that lack resources are likely to lose out to males that have more resources, so in bad conditions it pays for parents to “invest” more in daughters, which will have more opportunities to mate. It follows, as a kind of corollary, that when parents have plentiful resources they will devote those resources more to their sons, whereas when resources are scarce, parents will devote them more to their daughters. In short: If things are good, you have more boys, and give them more stuff. If things are bad, you have more girls, and give more of your stuff to them. Is this hypothesis correct? In new research of ours, to be published in the April issue of The Journal of Experimental Child Psychology, we suggest that in the case of breast-feeding, at least, it appears to be. In recent years, evidence has emerged suggesting that in various mammalian species, breast milk — which is, of course, a resource that can be given to children — is tailored for the sex of each offspring. For example, macaque monkey mothers produce richer milk (with higher gross energy and fat content) for sons than for daughters, but also provide greater quantities of milk and higher concentrations of calcium for daughters than for sons. © 2017 The New York Times Company
By NICHOLAS ST. FLEUR The tale of the Tasmanian tiger was tragic. Once numerous across Tasmania, the doglike marsupial was branded a sheep killer by colonists in the 1830s and hunted to extinction. The last of its kind, Benjamin, died in a zoo in 1936, and with it many secrets into the animals’ lives were lost. The striped creature, which is also known as the thylacine, was hardly studied when it was alive, depriving scientists of understanding the behavior of an important predator from Australia’s recent biological past. Now, for the first time, researchers have performed neural scans on the extinct carnivore’s brain, revealing insights that had been lost since the species went extinct. “Part of the myth about them is what exactly did they eat, how did they hunt and were they social?” said Dr. Gregory Berns, a neuroscientist at Emory University and lead author on the study, which was published Wednesday in the journal PLOS One. “These are questions nobody really knows the answers to.” Dr. Berns’s main research pertains to dogs and the inner workings of the canine brain, but after learning more about Tasmanian tigers, he became fascinated by the beasts. With their slender bodies, long snouts and sharp teeth, Tasmanian tigers looked as if they could be related to dogs, wolves or coyotes. But actually they are separated by more than 150 million years of evolution. It is a classic example of convergent evolution, in which two organisms that are not closely related develop similar features because of the environment they adapted to and the ecological role they played. To better understand thylacines, Dr. Berns spent two years tracking down two preserved Tasmanian tiger brains, one at the Smithsonian Institution and the other at the Australian Museum. Their brains, like those of all marsupials, are very different from the brains of placental mammals. The biggest difference is that they lack a corpus callosum, which is the part of the brain that connects the left and right hemispheres. © 2017 The New York Times Company
Claudia Dreifus Geneticists tell us that somewhere between 1 and 5 percent of the genome of modern Europeans and Asians consists of DNA inherited from Neanderthals, our prehistoric cousins. At Vanderbilt University, John Anthony Capra, an evolutionary genomics professor, has been combining high-powered computation and a medical records databank to learn what a Neanderthal heritage — even a fractional one — might mean for people today. We spoke for two hours when Dr. Capra, 35, recently passed through New York City. An edited and condensed version of the conversation follows. Q. Let’s begin with an indiscreet question. How did contemporary people come to have Neanderthal DNA on their genomes? A. We hypothesize that roughly 50,000 years ago, when the ancestors of modern humans migrated out of Africa and into Eurasia, they encountered Neanderthals. Matings must have occurred then. And later. One reason we deduce this is because the descendants of those who remained in Africa — present day Africans — don’t have Neanderthal DNA. What does that mean for people who have it? At my lab, we’ve been doing genetic testing on the blood samples of 28,000 patients at Vanderbilt and eight other medical centers across the country. Computers help us pinpoint where on the human genome this Neanderthal DNA is, and we run that against information from the patients’ anonymized medical records. We’re looking for associations. What we’ve been finding is that Neanderthal DNA has a subtle influence on risk for disease. It affects our immune system and how we respond to different immune challenges. It affects our skin. You’re slightly more prone to a condition where you can get scaly lesions after extreme sun exposure. There’s an increased risk for blood clots and tobacco addiction. To our surprise, it appears that some Neanderthal DNA can increase the risk for depression; however, there are other Neanderthal bits that decrease the risk. Roughly 1 to 2 percent of one’s risk for depression is determined by Neanderthal DNA. It all depends on where on the genome it’s located. © 2017 The New York Times Company
By Avi Selk “Oh Long Johnson,” a cat once said, back in the primordial history of Internet memes. “Oh Don Piano. Why I eyes ya.” Or so said the captions — appended to the gibberish of a perturbed house cat on “America's Funniest Home Videos” in 1999 and rediscovered in the YouTube era, when millions of people heard something vaguely human echo in a distant species. It was weird. And hilarious. And just maybe, profound. As the “Oh Long Johnson” craze was fading a few years ago, a wave of scientific discoveries about apes and monkeys began upending old assumptions about the origins of language. Only humans could willfully control their vocal tracts, went the established wisdom. Until Koko the gorilla coughed on command. Surely, then, our vowels were ours alone. But this month, researchers picked up British ohs in the babble of baboons. Study after study is dismantling a hypothesis that has stood for decades: that the seeds of language did not exist before modern humans, who got all the way to Shakespeare from scratch. And if so much of what we thought we knew about the uniqueness of human speech was wrong, some think it's time to take a second look at talking pet tricks. “It's humbling to understand that humans, in the end, are just another species of primate,” said Marcus Perlman, who led the Koko study in 2015. © 1996-2017 The Washington Post
Ian Sample Science editor Tempting as it may be, it would be wrong to claim that with each generation humans are becoming more stupid. As scientists are often so keen to point out, it is a bit more complicated than that. A study from Iceland is the latest to raise the prospect of a downwards spiral into imbecility. The research from deCODE, a genetics firm in Reykjavik, finds that groups of genes that predispose people to spend more years in education became a little rarer in the country from 1910 to 1975. The scientists used a database of more than 100,000 Icelanders to see how dozens of gene variants that affect educational attainment appeared in the population over time. They found a shallow decline over the 65 year period, implying a downturn in the natural inclination to rack up qualifications. But the genes involved in education affected fertility too. Those who carried more “education genes” tended to have fewer children than others. This led the scientists to propose that the genes had become rarer in the population because, for all their qualifications, better educated people had contributed less than others to the Icelandic gene pool. Spending longer in education and the career opportunities that provides is not the sole reason that better educated people tend to start families later and have fewer children, the study suggests. Many people who carried lots of genes for prolonged education left the system early and yet still had fewer children that the others. “It isn’t the case that education, or the career opportunities it provides, prevents you from having more children,” said Kari Stefansson, who led the study. “If you are genetically predisposed to have a lot of education, you are also predisposed to have fewer children.” © 2017 Guardian News and Media Limited
By Virginia Morell Only three known species go through menopause: killer whales, short-finned pilot whales, and humans. Two years ago, scientists suggested whales do this to focus their attention on the survival of their families rather than on birthing more offspring. But now this same team reports there’s another—and darker—reason: Older females enter menopause because their eldest daughters begin having calves, leading to fights over resources. The findings might also apply to humans, the scientists say. “What an interesting paper,” says Phyllis Lee, a behavioral ecologist at the University of Stirling in the United Kingdom, who was not involved in the study. “It brings two perspectives on menopause neatly together, and provides an elegant model for its rarity.” The new work came about when Darren Croft, a behavioral ecologist at the University of Exeter in the United Kingdom, and his colleagues looked back on their 2015 killer whale menopause study. “That showed how they helped and why they lived so long after menopause, but it didn’t explain why they stop reproducing,” he says, noting that in other species, such as elephants, older females also share wisdom and knowledge with their daughters, but continue to have calves. © 2017 American Association for the Advancement of Science.
By Peter Godfrey-Smith Adapted from Other Minds: The Octopus, the Sea and the Deep Origins of Consciousness, by Peter Godfrey-Smith. Copyright © 2016 by Peter Godfrey-Smith. Someone is watching you, intently, but you can't see them. Then you notice, drawn somehow by their eyes. You're amid a sponge garden, the seafloor scattered with shrublike clumps of bright orange sponge. Tangled in one of these sponges and the gray-green seaweed around it is an animal about the size of a cat. Its body seems to be everywhere and nowhere. The only parts you can keep a fix on are a small head and the two eyes. As you make your way around the sponge, so, too, do those eyes, keeping their distance, keeping part of the sponge between the two of you. The creature's color perfectly matches the seaweed, except that some of its skin is folded into tiny, towerlike peaks with tips that match the orange of the sponge. Eventually it raises its head high, then rockets away under jet propulsion. A second meeting with an octopus: this one is in a den. Shells are strewn in front, arranged with some pieces of old glass. You stop in front of its house, and the two of you look at each other. This one is small, about the size of a tennis ball. You reach forward a hand and stretch out one finger, and one octopus arm slowly uncoils and comes out to touch you. The suckers grab your skin, and the hold is disconcertingly tight. It tugs your finger, tasting it as it pulls you gently in. The arm is packed with sensors, hundreds of them in each of the dozens of suckers. The arm itself is alive with neurons, a nest of nervous activity. Behind the arm, large round eyes watch you the whole time. © 2017 Scientific American
By Tanya Lewis To the untrained listener, a bunch of babbling baboons may not sound like much. But sharp-eared experts have now found that our primate cousins can actually produce humanlike vowel sounds. The finding suggests the last common ancestor of humans and baboons may have possessed the vocal machinery for speech—hinting at a much earlier origin for language than previously thought. Researchers from the National Center for Scientific Research (CNRS) and Grenoble Alpes University, both in France, and their colleagues recorded baboons in captivity, finding the animals were capable of producing five distinct sounds that have the same characteristic frequencies as human vowels. As reported today in PLoS ONE, the animals could make these sounds despite the fact that, as dissections later revealed, they possess high voice boxes, or larynxes, an anatomical feature long thought to be an impediment to speech. “This breaks a serious logjam” in the study of language, says study co-author Thomas Sawallis, a linguist at the University of Alabama. “Theories of language evolution have developed based on the idea that full speech was only available to anatomically modern Homo sapiens,” approximately 70,000 to 100,000 years ago, he says, but in fact, “we could have had the beginnings of speech 25 million years ago.” The evolution of language is considered one of the hardest problems in science, because the process left no fossil evidence behind. One practical approach, however, is to study the mechanics of speech. Language consists roughly of different combinations of vowels and consonants. Notably, humans possess low larynxes, which makes it easier to produce a wide range of vowel sounds (and as Darwin observed, also makes it easier for us to choke on food). A foundational theory of speech production, developed by Brown University cognitive scientist Philip Lieberman in the 1960s, states the high larynxes and thus shorter vocal tracts of most nonhuman primates prevents them from producing vowel-like sounds. Yet recent research calls Lieberman’s hypothesis into question. © 2017 Scientific American
By Victoria Gill Science reporter, BBC News Researchers have used camera traps to film tool-use that is unique to chimpanzees in Ivory Coast. The footage revealed that the clever primates habitually make special water-dipping sticks - chewing the end of the stick to turn it into a soft, water-absorbing brush. Primate researchers examined the "dipping sticks" and concluded they were made specifically for drinking. The findings are reported in the American Journal of Primatology. Lead researcher Juan Lapuente, from the Comoe Chimpanzee Conservation Project, in Ivory Coast, explained that using similar brush-tipped sticks to dip into bees' nests for honey was common in chimpanzee populations across Africa. "But the use of brush-tipped sticks to dip for water is completely new and had never been described before," he told BBC News. "These chimps use especially long brush tips that they make specifically for water - much longer than those used for honey." The researchers tested the chimps' drinking sticks in an "absorption experiment", which showed that the particularly long brush-tips provided an advantage. "The longer the brush, the more water they collect," said Mr Lapuente. "This technology allows Comoe chimpanzees to obtain water from extremely narrow and deep tree holes that only they - and no other animal - can exploit, which [gives] them a superb adaptive advantage to survive in this dry and unpredictable environment." © 2017 BBC.
Link ID: 23075 - Posted: 01.10.2017
By Drake Baer Convergent evolution is what happens when nature takes different courses from different starting points to arrive at similar results. Consider bats, birds, and butterflies developing wings; sharks and dolphins finding fins; and echidnas and porcupines sporting spines. Or, if you want to annoy a traditionalist scientist, talk about humans and octopuses — and how they may both have consciousness. This is the thrust of Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, a new book by the scuba-diving, biology-specializing philosopher Peter Godfrey-Smith, originally of Australia and now a distinguished professor at the City University of New York’s graduate center. The book was written up by Olivia Judson in The Atlantic, and you should read the whole thing, but what I find mesmerizing is how categorically other the eight-tentacled ink-squirters are, and how their very nature challenges our conceptualizations of intelligence. “If we can make contact with cephalopods as sentient beings, it is not because of a shared history, not because of kinship, but because evolution built minds twice over,” Godfrey-Smith is quoted as saying. “This is probably the closest we will come to meeting an intelligent alien.” (He’s not the first to think so: The Hawaiian creation myth holds that octopuses are the only creatures left over from an earlier incarnation of the Earth, making them more proto-terrestrials than extraterrestrials.) © 2016, New York Media LLC.
By STEPH YIN Inuit who live in Greenland experience average temperatures below freezing for at least half of the year. For those who live in the north, subzero temperatures are normal during the coldest months. Given these frigid conditions, anthropologists have wondered for decades whether the Inuit in Greenland and other parts of the Arctic have unique biological adaptations that help them tolerate the extreme cold. A new study, published on Wednesday in Molecular Biology and Evolution, identifies gene variants in Inuit who live in Greenland, which may help them adapt to the cold by promoting heat-generating body fat. These variants possibly originated in the Denisovans, a group of archaic humans who, along with Neanderthals, diverged from modern humans about half a million years ago. “As modern humans spread around the world, they interbred with Denisovans and Neanderthals, who had already been living in these different environments for hundreds of thousands of years,” said Rasmus Nielsen, a professor of integrative biology at the University of California, Berkeley and an author of the paper. “This gene exchange may have helped some modern humans adapt to and conquer new environments.” The new study follows earlier research by Dr. Nielsen and colleagues, which found genetic mutations that might help the Inuit metabolize unsaturated fatty acids common in their diet of whales, seals and fish. In this study, Dr. Nielsen’s team focused on another distinct region in the Inuit genome, which seems to affect body fat distribution and other aspects of development. The researchers compared the genomes of nearly 200 Inuit with genomes of Neanderthals, Denisovans and modern populations around the world. © 2016 The New York Times Company
Link ID: 23011 - Posted: 12.23.2016
Ramin Skibba The high-pitched squeals of the humble bat may be as complex as the calls of dolphins and monkeys, researchers have found. A study published on 22 December in Scientific Reports1 reveals that the fruit bat is one of only a few animals known to direct its calls at specific individuals in a colony, and suggests that information in the calls of many social animals may be more detailed than was previously thought. Bats are noisy creatures, especially in their crowded caves, where they make calls to their neighbours. “If you go into a fruit-bat cave, you hear a cacophony,” says Yossi Yovel, a neuroecologist at Tel Aviv University in Israel who led the study. Until now, it has been difficult to separate this noise into distinct sounds, or to determine what prompted the individual to make a particular call. “Animals make sounds for a reason,” says Whitlow Au, a marine-bioacoustics scientist at the University of Hawaii at Manoa. “Most of the time, we don’t quite understand those reasons.” To find out what bats are talking about, Yovel and his colleagues monitored 22 captive Egyptian fruit bats (Rousettus aegyptiacus) around the clock for 75 days. They modified a voice-recognition program to analyse approximately 15,000 vocalizations collected during this time. The program was able to tie specific sounds to different social interactions captured by video, such as when two bats fought over food. © 2016 Macmillan Publishers