Chapter 6. Evolution of the Brain and Behavior

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Links 1 - 20 of 2006

By Ryan Dalton You might be forgiven for having never heard of the NotPetya cyberattack. It didn’t clear out your bank account, or share your social media passwords, or influence an election. But it was one of the most costly and damaging cyberattacks in history, for what it did target: shipping through ports. By the time the engineers at Maersk realized that their computers were infected with a virus, it was too late: worldwide shipping would grind to a halt for days. Imagine a similar situation, in which the target was another port: the synapse, the specialized port of communication between neurons. Much of our ability to learn and remember comes down to the behavior of synapses. What would happen then, if one neuron infected another with malware? Ports and synapses both run on rules, meant to ensure that their cargo can be exchanged not only quickly and reliably, but also adaptably, so that they can quickly adjust to current conditions and demands. This ‘synaptic plasticity’, is fundamental to the ability of animals to learn, and without it we would no more be able to tie our shoes than to remember our own names. Just as shipping rules are determined by treaties and laws, the rules of synaptic plasticity are written into a multitude of genes in our DNA. For example, one gene might be involved in turning up the volume on one side of the synapse, while another gene might ask the other side of the synapse to turn up the gain. Studying the function of these genes has been one of the core approaches to understanding what it is, at the microscopic level, to learn and to remember. © 2018 Scientific American

Keyword: Learning & Memory; Intelligence
Link ID: 25782 - Posted: 12.12.2018

Bruce Bower A nearly complete hominid skeleton known as Little Foot has finally been largely freed from the stony shell in which it was discovered in a South African cave more than 20 years ago. And in the first formal analyses of the fossils, researchers say the 3.67-million-year-old Little Foot belonged to its own species. In four papers posted online at bioRxiv.org between November 29 and December 5, paleoanthropologist Ronald Clarke of the University of the Witwatersrand in Johannesburg and colleagues assign Little Foot to a previously proposed species, Australopithecus prometheus, that has failed to gain traction among many researchers. Clarke has held that controversial view for more than a decade (SN: 5/2/15, p. 8). He found the first of Little Foot’s remains in a storage box of fossils from a site called Sterkfontein in 1994. Excavations of the rest of the skeleton began in 1997. Many other researchers, however, regard Little Foot as an early member of a hominid species called Australopithecus africanus. Anthropologist Raymond Dart first identified A. africanus in 1924 from an ancient youngster’s skull called the Taung Child. Hundreds of A. africanus fossils have since been found in South African caves, including Sterkfontein. One of those caves, Makapansgat, produced a partial braincase that Dart assigned to A. prometheus in 1948. But Dart dropped that label after 1955, assigning the braincase and another Makapansgat fossil to A. africanus. |© Society for Science & the Public 2000 - 2018.

Keyword: Evolution
Link ID: 25778 - Posted: 12.12.2018

By JoAnna Klein A macaw named Poncho starred in movies like “102 Dalmatians,” “Dr. Doolittle” and “Ace Ventura: Pet Detective” before retiring in England. She recently celebrated her 90th birthday. Alex, an African grey parrot who lived to 31, knew colors, shapes and numbers, and communicated using basic expressions. He could do what toddlers only do after a certain stage of development — know when something is hidden from view. And they’re just two of the many parrots in the world who have surprised us with their intelligence, skills and longevity. “Nature does these experiments for us, and then we have to go and ask, how did this happen?” said Dr. Claudio Mello, a neuroscientist at Oregon Health and Science University. So he and a team of nearly two dozen scientists looked for clues in the genome of the blue-fronted Amazon parrot in Brazil, his home country. After comparing its genome with those of dozens of other birds, the researchers’ findings suggest that evolution may have made parrots something like the humans of the avian world. In some ways, the long-lived feathered friends are as genetically different from other birds as humans are from other primates. Their analysis, published Thursday in Current Biology, also highlights how two very different animals — parrots and humans — can wind up finding similar solutions to problems through evolution. A general rule of life span in birds and other animals is the bigger or heavier you are, the longer you live. A small bird like a finch may live five to eight years, while bigger ones like eagles or cranes can live decades. The blue-fronted Amazon and some other parrots are even more exceptional, in that they can live up to 66 years — in some cases outliving their human companions. © 2018 The New York Times Company

Keyword: Intelligence; Evolution
Link ID: 25764 - Posted: 12.08.2018

One of the animals that's thought to give creatures like apes, dolphins and crows a run for their money when it comes to intelligence is the octopus. For those other animals, there's a pattern to how they evolved to be so smart — they live long, socially complex lives. But that's not the case for octopuses that live solitary lives for the year or two they usually survive. Now scientists think they've figured out how the octopus became so so smart, and it has to do with the loss of their shell through evolution. "Octopuses, unlike many other molluscs, they do not have a protective shell," said Piero Amodio, the lead author on the new study published in the journal Trends in Ecology & Evolution about how cephalopods (octopuses and their relatives) gained their intelligence. "So [octopuses] are very, very vulnerable to many kinds of predators — from fishes to marine mammals to birds — and the idea is that by becoming quite smart, this is a kind of weapon they can use to avoid being eaten." Amodio, a PhD student at the University of Cambridge, told Quirks & Quarks host Bob McDonald that this evolutionary process differs from those that led to intelligence in other groups of vertebrates. Intelligence in other vertebrates is thought to have arisen because they live long and socially complex lives. Building a brain is a metabolically labour intensive process, so it's a big investment for an animal to develop a big brain like in apes, dolphins, and crows — an investment they get a return on when they live a long time. ©2018 CBC/Radio-Canada.

Keyword: Evolution; Intelligence
Link ID: 25763 - Posted: 12.08.2018

By C. Claiborne Ray Q. Do lizards dream like people do? A. Some species of lizards do have two sleep phases, one resembling the dreaming phase of human beings, other mammals and birds. In 2016, a study of the central bearded dragon, Pogona vitticeps, found slow-wave and rapid-eye-movement states that cycled back and forth in 80-second increments over sleep periods of six to 10 hours. In other animals, slow-wave sleep is usually described as deep, dreamless sleep, while rapid eye movements are linked to shallower sleep and dreaming. Recently scientists in France collected data on brain activity, heart rates and behavioral patterns, including eye movement, in the sleeping Argentine black-and-white tegu (Salvator merianae). The scientists also documented two sleep states, suggesting that the animals do experience something like R.E.M. sleep. In both studies, the researchers suggested that dreaming may have originated with a common ancestor of mammals, birds and lizards, rather than developing independently in various species. © 2018 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 25760 - Posted: 12.08.2018

By Carl Zimmer To demonstrate how smart an octopus can be, Piero Amodio points to a YouTube video. It shows an octopus pulling two halves of a coconut shell together to hide inside. Later the animal stacks the shells together like nesting bowls — and carts them away. “It suggests the octopus is carrying these tools around because it has some understanding they may be useful in the future,” said Mr. Amodio, a graduate student studying animal intelligence at the University of Cambridge in Britain. But his amazement is mixed with puzzlement. For decades, researchers have studied how certain animals evolved to be intelligent, among them apes, elephants, dolphins and even some birds, such as crows and parrots. But all the scientific theories fail when it comes to cephalopods, a group that includes octopuses, squid and cuttlefish. Despite feats of creativity, they lack some hallmarks of intelligence seen in other species. “It’s an apparent paradox that’s been largely overlooked in the past,” said Mr. Amodio. He and five other experts on animal intelligence explore this paradox in a paper published this month in the journal Trends in Ecology and Evolution. For scientists who study animal behavior, intelligence is not about acing a calculus test or taking a car apart and putting it back together. Intelligence comprises sophisticated cognitive skills that help an animal thrive. That may include the ability to come up with solutions to the problem of finding food, for example, or a knack for planning for some challenge in the future. Intelligent animals don’t rely on fixed responses to survive — they can invent new behaviors on the fly. © 2018 The New York Times Company

Keyword: Intelligence; Evolution
Link ID: 25741 - Posted: 12.01.2018

Susan Milius Mom nurses her young for weeks on milk that has four times the protein of a cow’s. Yet this mother’s not a mammal. She’s a jumping spider with eight legs and a taste for fruit flies. We mammals have named ourselves after our mammary glands. Yet other animals, from tsetse flies to pigeons, secrete their own versions of milk for their babies. The newly discovered nursing in Toxeus magnus could be the most mammal-like of all, a research team from China proposes in the Nov. 30 Science. Biologists have recognized T. magnus as a species since 1933, but a small spider’s mothering habit was easy to miss. The spiders hunt beasts such as fruit flies and will retreat to a little nest, perhaps attached to a leaf, to raise a family. Study coauthor Zhanqi Chen of the Chinese Academy of Sciences in Menglunzhen, who studies spider behavior, noticed several T. magnus sharing a nest in 2012 and wondered if the species had some sort of extended parental care. It was another five years before he spotted the nursing behavior, when a spiderling clamped itself against mom’s underside one exciting July night in 2017. With a T. magnus female under a microscope, a gentle finger push on the underside of the abdomen will squeeze a tiny bead of white liquid out of a crease called an epigastric furrow, the researchers say. For the first week or so after eggs hatch, a spider mom leaves milk droplets around the nest for the crawling dots of her young to drink. Then nursing turns more mammalian, with little ones pressing themselves against their mother’s body. |© Society for Science & the Public 2000 - 2018

Keyword: Sexual Behavior; Evolution
Link ID: 25737 - Posted: 11.30.2018

By Virginia Morell Like any fad, the songs of humpback whales don’t stick around for long. Every few years, males swap their chorus of squeaks and groans for a brand new one. Now, scientists have figured out how these “cultural revolutions” take place. All male humpbacks in a population sing the same song, and they appear to learn new ones somewhat like people do. Males in the eastern Australian population of humpbacks, for example, pick up a new song every few years from the western Australian population at shared feeding grounds or while migrating. Over the next few years, the songs spread to all South Pacific populations. To understand how the whales learn the novel ballads, scientists analyzed eastern Australian whale songs over 13 consecutive years. Using spectrograms of 412 song cycles from 95 singers, the scientists scored each tune’s complexity for the number of sounds and themes, and studied the subtle variations individual males can add to stand out. Complexity increased as the songs evolved (as heard in the video below), the team reports today in the Proceedings of the Royal Society B. But after a song revolution, the ballads became shorter with fewer sounds and themes. The revolutionary songs may be less complex than the old ones because the whales can only learn a certain amount of new material at a time, the scientists conclude. That could mean that although humpback whales are still the crooners of the sea, their learning skills are a bit limited. © 2018 American Association for the Advancement of Scienc

Keyword: Animal Communication; Language
Link ID: 25705 - Posted: 11.21.2018

Ned Rozell Alaska chickadees have proven themselves brainier than Colorado chickadees. A researcher at the University of California Davis once compared black-capped chickadees from Anchorage to chickadees from Windsor, Colorado, and found that the Alaska birds cached more sunflower seeds and found the seeds quicker when they later searched for them. The Alaska chickadees also had brains that contained more neurons than those of Colorado chickadees. Vladimir Pravosudov of the UC Davis psychology department performed the study to test the notion that northern birds would be better at hiding and finding seeds than birds in a more moderate climate. He chose to capture birds in Anchorage, which has a day length of about 5 hours, 30 minutes on Dec. 22, and compare them to birds he captured near Windsor, about 50 miles north of Denver, where the Dec. 22 day length is about 9 hours, 15 minutes. With the help of biologist Colleen Handel of the U.S. Geological Survey in Anchorage, Pravosudov captured 15 black-capped chickadees using a mist net at bird feeders around Anchorage in fall 2000. He later captured 12 black-capped chickadees near Windsor. All the birds went to his lab in Davis, where he gave them the same food and amount of daylight for 45 days. After 45 days he tested eight birds from Alaska and eight from Colorado in a room with 70 caching holes drilled in wooden blocks and trees. In late summer through fall, black-capped chickadees gather and hide seeds, insects and other foods to retrieve later, when they have fewer hours of daylight to feed and less food is available. Though black-capped chickadees live their entire lives within a few square acres, the species ranges from as far north as Anaktuvuk Pass in Alaska to as far south as New Mexico. © 2018 Anchorage Daily News

Keyword: Learning & Memory; Evolution
Link ID: 25689 - Posted: 11.16.2018

Bruce Bower Neandertals are shaking off their reputation as head bangers. Our close evolutionary cousins experienced plenty of head injuries, but no more so than late Stone Age humans did, a study suggests. Rates of fractures and other bone damage in a large sample of Neandertal and ancient Homo sapiens skulls roughly match rates previously reported for human foragers and farmers who have lived within the past 10,000 years, concludes a team led by paleoanthropologist Katerina Harvati of the University of Tübingen in Germany. Males suffered the bulk of harmful head knocks, whether they were Neandertals or ancient humans, the scientists report online November 14 in Nature. “Our results suggest that Neandertal lifestyles were not more dangerous than those of early modern Europeans,” Harvati says. Until recently, researchers depicted Neandertals, who inhabited Europe and Asia between around 400,000 and 40,000 years ago, as especially prone to head injuries. Serious damage to small numbers of Neandertal skulls fueled a view that these hominids led dangerous lives. Proposed causes of Neandertal noggin wounds have included fighting, attacks by cave bears and other carnivores and close-range hunting of large prey animals. Paleoanthropologist Erik Trinkaus of Washington University in St. Louis coauthored an influential 1995 paper arguing that Neandertals incurred an unusually large number of head and upper-body injuries. Trinkaus recanted that conclusion in 2012, though. All sorts of causes, including accidents and fossilization, could have resulted in Neandertal skull damage observed in relatively small fossil samples, he contended (SN: 5/27/17, p. 13). |© Society for Science & the Public 2000 - 2018.

Keyword: Evolution; Aggression
Link ID: 25686 - Posted: 11.15.2018

By Virginia Morell When wild orangutans spot a predator, they let out a loud “kiss-squeak,” a call that sounds like a human smooching. That noise tells tigers and other enemies, “I’ve seen you,” scientists believe, and it also lets other orangutans know danger is near. Now, researchers report having heard orangutans making this call long after predators have passed—the first evidence that primates other than humans can “talk” about the past. “The results are quite surprising,” says Carel van Schaik, a primatologist at the University of Zurich in Switzerland who was not involved in the work. The ability to talk about the past or the future “is one of the things that makes language so effective,” he says. That suggests, he adds, that the new findings could provide clues to the evolution of language itself. Many mammals and birds have alarm calls, some of which include information on the type and size of a predator, its location and distance, and what level of danger it poses. But until now, researchers have never heard wild animals announcing danger after the fact. Adriano Reis e Lameira, a postdoctoral student at the University of St. Andrews in the United Kingdom, was examining alarm calls in orangutans in Sumatra’s dense Ketambe forest, where the primates have been observed for nearly 40 years. He set up a simple experiment to investigate their alarm calls: A scientist draped in a tiger-striped, spotted, or plain sheet walked on all fours along the forest floor, right underneath lone female orangutans sitting in trees at heights of 5 to 20 meters above the ground. © 2018 American Association for the Advancement of Science

Keyword: Evolution; Language
Link ID: 25685 - Posted: 11.15.2018

By Neil Genzlinger Dorothy L. Cheney, whose careful research into how primates live and communicate revealed the surprising complexity of their thought processes and social structures, died on Friday at her home in Devon, Pa. She was 68. Her husband and research partner, Robert M. Seyfarth, said the cause was breast cancer. “Cheney was a spectacular scientist,” Robert M. Sapolsky, a professor of biology and neurology at Stanford University and the author of books like “A Primate’s Memoir,” said by email. “Along with Robert Seyfarth, she did wonderfully clever, elegant field experiments that revealed how other primates think about the world — showing that they think in far more sophisticated and interesting ways than people anticipated.” Rather than doing their research in laboratories, Dr. Cheney and Dr. Seyfarth spent long stretches in the wilds of Africa and elsewhere, studying gorillas, baboons, vervet monkeys and other animals. One of their best-known experiments, conducted in Kenya in 1977, showed that vervets made distress sounds not just involuntarily, out of fear, but to convey a specific message about a given threat. They hid loudspeakers in bushes, played recorded sounds of vervets and watched the reaction. A particular bark sent the animals scurrying up trees because it was a warning about leopards; a low-pitched staccato noise had them looking skyward for predatory eagles. They summarized their research in their first book, “How Monkeys See the World: Inside the Mind of Another Species” (1990). Later research in Botswana included insights into the hierarchical nature of baboon societies and its possible evolutionary effects. “Because Western scientists learned about primates by examining corpses or observing single animals brought home as pets,” they wrote in their 2007 book, “Baboon Metaphysics: The Evolution of a Social Mind,” “few if any ever learned what can be discovered only through long, patient observation: that the most human features of monkeys and apes lie not in their physical appearance but in their social relationships.” © 2018 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 25683 - Posted: 11.15.2018

Jennifer Leman Some moths aren’t so easy for bats to detect. The cabbage tree emperor moth has wings with tiny scales that absorb sound waves sent out by bats searching for food. That absorption reduces the echoes that bounce back to bats, allowing Bunaea alcinoe to avoid being so noticeable to the nocturnal predators, researchers report online November 12 in the Proceedings of the National Academy of Sciences. “They have this stealth coating on their body surfaces which absorbs the sound,” says study coauthor Marc Holderied, a bioacoustician at the University of Bristol in England. “We now understand the mechanism behind it.” Bats sense their surroundings using echolocation, sending out sound waves that bounce off objects and return as echoes picked up by the bats’ supersensitive ears (SN: 9/30/17, p. 22). These moths, without ears that might alert them to an approaching predator, have instead developed scales of a size, shape and thickness suited to absorbing ultrasonic sound frequencies used by bats, the researchers found. The team shot ultrasonic sound waves at a single, microscopic scale and observed it transferring sound wave energy into movement. The scientists then simulated the process with a 3-D computer model that showed the scale absorbing up to 50 percent of the energy from sound waves. What’s more, it isn’t just wings that help such earless moths evade bats. Other moths in the same family as B. alcinoe also have sound-absorbing fur, the same researchers report online October 18 in the Journal of the Acoustical Society of America. |© Society for Science & the Public 2000 - 2018

Keyword: Hearing; Evolution
Link ID: 25679 - Posted: 11.14.2018

David Sington Aubrey Manning’s hugely popular 1998 BBC series Earth Story, about the evolution and shaping of the planet Earth, inspired a generation and led to a noticeable increase in students applying to read earth sciences. Yet, Aubrey, who has died aged 88, was not a geologist, but an ethologist, whose work made an important contribution to the understanding of how animal behaviour plays a role in the evolution of new species. In a series of experiments at Oxford and Edinburgh universities – he was professor of natural history (1973-97) at the latter – Aubrey showed how mutations in genes that affect the behaviour of fruit flies could lead to reproductive isolation, a key mechanism in the creation of new species. This work laid the foundation for the modern study of the evolutionary genetics of behaviour. His 1967 publication An Introduction to Animal Behaviour, now in its sixth edition, is still the standard textbook in its field, and his lectures were so popular – packed with students from many other courses – that the university took to scheduling them for 9am on Mondays as the most effective way to get undergraduates out of bed. It was this reputation as a superb communicator of science that led the BBC to his door. When as its producer I approached him in 1997 to present Earth Story, Aubrey, with typical modesty, protested that I had the wrong man and insisted on introducing me to his geological colleagues. However, it was the very fact that the subject was new to him that was the secret of the ventures success. © 2018 Guardian News and Media Limited

Keyword: Evolution
Link ID: 25667 - Posted: 11.12.2018

By James Gorman David Hu was changing his infant son’s diaper when he got the idea for a study that eventually won him the Ig Nobel prize. No, not the Nobel Prize — the Ig Nobel prize, which bills itself as a reward for “achievements that make people laugh, then think.” As male infants will do, his son urinated all over the front of Dr. Hu’s shirt, for a full 21 seconds. Yes, he counted off the time, because for him curiosity trumps irritation. That was a long time for a small baby, he thought. How long did it take an adult to empty his bladder? He timed himself. Twenty-three seconds. “Wow, I thought, my son urinates like a real man already.” He recounts all of this without a trace of embarrassment, in person and in “How to Walk on Water and Climb up Walls: Animal Movements and the Robotics of the Future,” just published, in which he describes both the silliness and profundity of his brand of research. No one who knows Dr. Hu, 39, would be surprised by this story. His family, friends, the animals around him — all inspire research questions. His wife, Jia Fan, is a marketing researcher and senior data scientist at U.P.S. When they met, she had a dog, and he became intrigued by how it shook itself dry. So he set out to understand that process. Now, he and his son and daughter sometimes bring home some sort of dead animal from a walk or a run. The roadkill goes into the freezer, where he used to keep frozen rats for his several snakes. (The legless lizard ate dog food). “My first reaction is not, oh, it’s gross. It’s ‘Do we have space in our freezer,’” Dr. Fan said. He also saves earwax and teeth from his children, and lice and lice eggs from the inevitable schoolchild hair infestations. “We have separate vials for lice and lice eggs,” he pointed out. © 2018 The New York Times Company

Keyword: Movement Disorders; Evolution
Link ID: 25650 - Posted: 11.06.2018

By James Gorman If you love spiders, you will really love jumping spiders. (If you hate spiders, try reading this article on dandelions.) O.K., if you’re still here, jumping spiders are predators that stalk their prey and leap on them, like a cat. They are smart, agile and have terrific eyesight. It has been clear for a long time that their vision is critical to the way they hunt, and to the accuracy of their leaps. But a lot has remained unknown about the way their eyes work together. To find out more, Elizabeth Jakob, a spider biologist at the University of Massachusetts, led a team of researchers from the United States, Kenya and New Zealand in an investigation of spider vision. The first step was getting a custom-built spider eye tracker, similar to ones used on humans, to follow a spider’s gaze. Actually, Dr. Jakob had two made, probably the only two in the world. She has one and her colleagues in New Zealand have the other. Jumping spiders have eight eyes. Two big eyes, right in the center of what you might call the spider’s forehead, are the principal ones, and they pick up detail and color. Of the other three pairs, a rear set looks backward, a middle set is as yet a bit of a mystery, and the foremost detect motion. The lenses of the main eyes are attached by flexible tubes to retinas. A camera was set up to look down those tubes and see the activity of the retinas, which look a bit like boomerangs. The inside of the spider’s head was lit by ultraviolet light, which penetrates the outer carapace. But as accurate as the main eyes are, they only see what is in front of them. If they had to find prey, it would be like using a narrow flashlight beam to explore a dark room. Not very efficient. The researchers found that the front pair of secondary eyes, the motion detectors, tell the main pair of eyes where to look. When they were painted over temporarily and the spider was presented with moving images, it had no idea where to look. © 2018 The New York Times Company

Keyword: Vision; Evolution
Link ID: 25648 - Posted: 11.06.2018

By Daniel Engber Two decades ago, in late summer 1998, the journal Nature came out with an outrageous claim: Both women and men, a research paper argued, prefer faces with more “girlish” features. The authors of the study, based in Scotland and Japan, had expected the opposite result—that square-jawed, hunky faces, more Harrison Ford than Leonardo DiCaprio, would be deemed more attractive. “Our team has been working on this study for four years,” one of the scientists, Ian Penton-Voak, told the New York Times in advance of publication. “When it was found early on that there was a preference for feminized male faces, nobody believed it, so we did it again, and again. The preference for a feminized face keeps coming up.” Could it really be the case that everyone prefers a man with a gentle nose and a low-T brow? If so, then why are (or were) Harrison Ford and Leonardo DiCaprio both considered highly sexy? And what about the other sexy ’90s dyads of George Clooney and Jude Law, and Johnny Depp and Nick Nolte? The Nature data were no less perplexing for evolutionary psychologists like Penton-Voak. From that field’s perspective, manly features are indicative of a male’s reproductive fitness. Given this assumption, one might guess that women have evolved to find those traits the most appealing, since they help identify the sort of men with whom you could make the strongest, most immunocompetent children. What would women get from delicate men? A year later, in the summer of ’99, Penton-Voak and colleagues offered the beginnings of an explanation. For a second study, also out in Nature, and also drawn from research done in Scotland and Japan, they once again asked young women to evaluate male faces that had been digitally feminized to varying degrees—only now they had the women do so twice, at different points during their menstrual cycles. They found that a woman’s predilection for men with girlish features waxed and waned throughout the lunar month: When she looked at faces in the days leading up to ovulation, her tastes would tend a bit more masculine; later on she’d flip back the other way. © 2018 The Slate Group LLC

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 25619 - Posted: 10.26.2018

By Victoria Gill Science correspondent, BBC News Clever, tool-using crows have surprised scientists once again with remarkable problem-solving skills. In a task designed to test their tool-making prowess, New Caledonian crows spontaneously put together two short, combinable sticks to make a longer "fishing rod" to reach a piece of food. The findings are published in the journal Scientific Reports. Scientists say the demonstration is a "window into how another animals' minds work". How do you test a bird's tool-making skills? New Caledonian crows are known to spontaneously use tools in the wild. This task, designed by scientists at the Max Planck Institute for Ornithology in Seewiesen, Germany, and the University of Oxford, presented the birds with a novel problem that they needed to make a new tool in order to solve. It involved a "puzzle box" containing food behind a door that left a narrow gap along the bottom. With the food deep inside the box and only short sticks - too short to reach the food - the crows were left to work out what to do. The sticks were designed to be combinable - one was hollow to allow the other to slot inside. And with no demonstration or help, four out of the eight crows inserted one stick into another and used the resulting longer tool to fish for and extract the food from the box. "They have never seen this compound tool, but somehow they can predict its properties," explained one of the lead researchers, Prof Alex Kacelnik. "So they can predict what something that does not yet exist would do if they made it. Then they can make it and they can use it. © 2018 BBC

Keyword: Intelligence; Evolution
Link ID: 25615 - Posted: 10.25.2018

By Diana Kwon Spanish neuroscientist Santiago Ramón y Cajal revolutionized the study of the brain when he observed neurons for the first time. His investigations, now more than 100 years old, revealed intricate details of nerve cells in many different animals, including humans—rootlike dendrites attached to bulbous cell bodies, from which extend long, slender axons. Cajal’s examinations also revealed dendrites (via which nerve cells receive signals from other neurons) were much longer in humans than in rodents and other animals, even other non-human primates. A new study, published this week in Cell, shows that in people these antennalike projections also have distinct electrical properties that may help explain how the brain processes arriving information. Scientists have been meticulously studying dendrites in the decades since Cajal’s initial observations. Still, “the only thing we really knew about human dendrites was their anatomy,” Massachusetts Institute of Technology neuroscientist Mark Harnett says. “There was a lot of potential for human dendrites to be doing something different because of their length, but there was no published work, as far as I know, on their actual electrical properties.” So Harnett and his colleagues set out to investigate whether the length of dendrites affected electrical signals transmitted through them. With the help of a neurologist, Sydney Cash of Massachusetts General Hospital, they were able to obtain brain tissue that had been removed from epilepsy patients undergoing routine surgery to help allay seizures—a procedure in which physicians routinely remove part of the temporal cortex to get to the hippocampus, a structure deep inside the brain where seizures typically originate. © 2018 Scientific American

Keyword: Brain imaging; Evolution
Link ID: 25594 - Posted: 10.20.2018

By Jason Bittel The first mammals first lived some 160 million years ago, in a world ruled by reptiles. And now scientists suggest that hiding in the dark from these terrifying beasts may have left an imprint in mammals’ genes that can still be seen today. Most mammals were no bigger than a squirrel back then, and it would have been much safer to come out only at night, thereby avoiding most of the nastiest maws and claws. A new study published Thursday in Current Biology suggests that living largely in the dark for millions of years might explain how mammals lost a light-sensitive trick that nearly every other living thing possesses. You see, if you were to examine the DNA of a turtle, an orchid, a coral, or even a bacterium, you would find a quirky little set of genes that allows these organisms to repair damage caused by one kind of sunlight with energy absorbed from another kind of sunlight. Think of it like a solar panel that is both harmed and healed by the sun. How is it possible that we lost an evolutionary strategy so advantageous it’s been found in every other living thing where scientists have looked for it? Well, you might blame the dinosaurs—or at least how scary they were. All that time spent in darkness, when most dinosaurs weren’t active, may have affected the way placental mammals evolved. Scientists call this theory the “nocturnal bottleneck,” and it’s supported by various mammalian oddities such as the shape of our eyes, the composition of our retinas, and our heightened senses of smell and hearing—all of which point to a long history of living in the dark.

Keyword: Biological Rhythms; Evolution
Link ID: 25572 - Posted: 10.15.2018