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By Christa Lesté-Lasserre In the animal kingdom, killer whales are social stars: They travel in extended, varied family groups, care for grandchildren after menopause, and even imitate human speech. Now, marine biologists are adding one more behavior to the list: forming fast friendships. A new study suggests the whales rival chimpanzees, macaques, and even humans when it comes to the kinds of “social touching” that indicates strong bonds. The study marks “a very important contribution to the field” of social behavior in dolphins and whales, says José Zamorano-Abramson, a comparative psychologist at the Complutense University of Madrid who wasn’t involved in the work. “These new images show lots of touching of many different types, probably related to different kinds of emotions, much like the complex social dynamics we see in great apes.” Audio and video recordings have shown how some marine mammals maintain social structures—including male dolphins that learn the “names” of close allies. But there is little footage of wild killer whales—which hunt and play in open water. Although the whales only swim at about 6 kilometers per hour, it’s hard to fully observe them from boats, and they might not act naturally near humans, Zamorano-Abramson says. That’s where drone technology came swooping in. Michael Weiss, a behavioral ecologist at the Center for Whale Research in Friday Harbor, Washington, teamed up with colleagues to launch unmanned drones from their 6.5-meter motorboat and from the shores of the northern Pacific Ocean, flying them 30 to 120 meters above a pod of 22 southern resident killer whales. That was high enough to respect federal aviation requirements—and not bother the whales. They logged 10 hours of footage over a 10-day period, marking the first time drones have been used to study friendly physical contacts in any cetacean. © 2021 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 27864 - Posted: 06.19.2021

By Richard Sima An elephant’s trunk is a marvel of biology. Devoid of any joints or bone, the trunk is an appendage made of pure muscle that is capable of both uprooting trees and gingerly plucking individual leaves and also boasts a sense of smell more powerful than a bomb-sniffing dog’s. Elephants use their trunks in a variety of ways. They use it to drink, store and spray water, and they also blow air through it to communicate — their 110-decibel bellows can be heard for miles. “It’s like a muscular multitool,” said Andrew Schulz, a mechanical engineering doctoral student at the Georgia Institute of Technology. In a study published Wednesday in The Journal of the Royal Society Interface, Mr. Schulz and his colleagues reported on how elephants can use their trunks for yet another function: applying suction to grab food, a behavior previously thought to be exclusive to fishes. Despite the ubiquity of elephants in children’s books and nature documentaries, there are numerous gaps in scientific knowledge about the biomechanics of their trunks that the new study helps fill. For example, the most recent detailed account of elephant trunk anatomy is a hand-drawn monograph that was published in 1908, Mr. Schulz said. Contrary to popular belief, the trunk does not act like a straw. “What they do is actually drink water into their trunk and they store it,” Mr. Schulz said. “So the elephant trunk is actually like a trunk.” Mr. Schulz completed his research in the lab of David Hu, which studies how animals move and function with an eye toward applying the discoveries toward human engineering problems. He said one reason elephants’ anatomy is poorly understood is because they are difficult to work with. © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27840 - Posted: 06.02.2021

By Natalie Angier Julia, her friends and family agreed, had style. When, out of the blue, the 18-year-old chimpanzee began inserting long, stiff blades of grass into one or both ears and then went about her day with her new statement accessories clearly visible to the world, the other chimpanzees at the Chimfunshi wildlife sanctuary in Zambia were dazzled. Pretty soon, they were trying it, too: first her son, then her two closest female friends, then a male friend, out to eight of the 10 chimps in the group, all of them struggling, in front of Julia the Influencer — and hidden video cameras — to get the grass-in-the-ear routine just right. “It was quite funny to see,” said Edwin van Leeuwen of the University of Antwerp, who studies animal culture. “They tried again and again without success. They shivered through their whole bodies.” Dr. van Leeuwen tried it himself and understood why. “It’s not a pleasant feeling, poking a piece of grass far enough into the ear to stay there,” he said. But once the chimpanzees had mastered the technique, they repeated it often, proudly, almost ritualistically, fiddling with the inserted blades to make sure others were suitably impressed. Julia died more than two years ago, yet her grassy-ear routine — a tradition that arose spontaneously, spread through social networks and skirts uncomfortably close to a human meme or fad — lives on among her followers in the sanctuary. The behavior is just one of many surprising examples of animal culture that researchers have lately divulged, as a vivid summary makes clear in a recent issue of Science. Culture was once considered the patented property of human beings: We have the art, science, music and online shopping; animals have the instinct, imprinting and hard-wired responses. But that dismissive attitude toward nonhuman minds turns out to be more deeply misguided with every new finding of animal wit or whimsy: Culture, as many biologists now understand it, is much bigger than we are. © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27809 - Posted: 05.08.2021

By Charles Choi Even after ancient humans took their first steps out of Africa, they still unexpectedly may have possessed brains more like those of great apes than modern humans, a new study suggests. For decades, scientists had thought modern humanlike organization of brain structures evolved soon after the human lineage Homo arose roughly 2.8 million years ago (SN: 3/4/15). But an analysis of fossilized human skulls that retain imprints of the brains they once held now suggests such brain development occurred much later. Modernlike brains may have emerged in an evolutionary sprint starting about 1.7 million years ago, researchers report in the April 9 Science. What sets modern humans apart most from our closest living relatives, the great apes, is most likely our brain. To learn more about how the modern human brain evolved, the researchers analyzed replicas of the brain’s convoluted outer surface, re-created from the oldest known fossils to preserve the inner surfaces of early human skulls. The 1.77-million to 1.85-million-year-old fossils are from the Dmanisi archaeological site in the modern-day nation of Georgia and were compared with bones from Africa and Southeast Asia ranging from roughly 2 million to 70,000 years old. The scientists focused on the brain’s frontal lobes, which are linked with complex mental tasks such as toolmaking and language. Early Homo from Dmanisi and Africa still apparently retained a great ape–like organization of the frontal lobe 1.8 million years ago, “a million or so years later than previously thought,” says paleoanthropologist Philipp Gunz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who did not take part in this study. © Society for Science & the Public 2000–2021.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27768 - Posted: 04.10.2021

By Annie Roth A few years ago, Sayaka Mitoh, a Ph.D. candidate at Nara Women’s University in Japan, was perusing her lab’s vast collection of sea slugs when she stumbled upon a gruesome sight. One of the lab’s captive-raised sea slugs, an Elysia marginata, had somehow been decapitated. When Ms. Mitoh peered into its tank to get a better look, she noticed something even more shocking: The severed head of the creature was moving around the tank, munching algae as if there was nothing unusual about being a bodiless slug. Ms. Mitoh also saw signs that the sea slug’s wound was self-inflicted: It was as if the sea slug had dissolved the tissue around its neck and ripped its own head off. Self-amputation, known as autotomy, isn’t uncommon in the animal kingdom. Having the ability to jettison a body part, such as a tail, helps many animals avoid predation. However, no animal had ever been observed ditching its entire body. “I was really surprised and shocked to see the head moving,” said Ms. Mitoh, who studies the life history traits of sea slugs. She added that she expected the slug “would die quickly without a heart and other important organs.” But it not only continued to live, it also regenerated the entirety of its lost body within three weeks. This prompted Ms. Mitoh and her colleagues to conduct a series of experiments aimed at figuring out how and why some sea slugs guillotine themselves. The results of their experiments, published Monday in Current Biology, provide evidence that Elysia marginata, and a closely related species, Elysia atroviridis, purposefully decapitate themselves in order to facilitate the growth of a new body. Although more research is needed, the researchers suspect these sea slugs ditch their bodies when they become infected with internal parasites. © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27727 - Posted: 03.11.2021

James Doubek By being able to wait for better food, cuttlefish — the squishy sea creatures similar to octopuses and squids — showed self-control that's linked to the higher intelligence of primates. It was part of an experiment by Alex Schnell from the University of Cambridge and colleagues. "What surprised me the most was that the level of self-control shown by our cuttlefish was quite advanced," she tells Lulu Garcia-Navarro on Weekend Edition. The experiment was essentially a take on the classic "marshmallow" experiment from the 1960s. In that experiment, young children were presented with one marshmallow and told that if they can resist eating it, unsupervised, for several minutes, they will get two marshmallows. But if they eat it that's all they get. The conventional wisdom has been that children who are able to delay gratification do better on tests and are more successful later in life. (There are of course many caveats when talking about the human experiments.) To adapt the experiment for cuttlefish, the researchers first figured out the cuttlefish's favorite food: live grass shrimp; and their second-favorite food: a piece of king prawn. Instead of choosing one or two marshmallows, the cuttlefish had to choose either their favorite food or second-favorite food. "Each of the food items were placed in clear chambers within their tank," Schnell says. "One chamber would open immediately, whereas the other chamber would only open after a delay." © 2021 npr

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27724 - Posted: 03.11.2021

By Jonathan Lambert One Volta’s electric eel — able to subdue small fish with an 860-volt jolt — is scary enough. Now imagine over 100 eels swirling about, unleashing coordinated electric attacks. Such a sight was assumed to be only the stuff of nightmares, at least for prey. Researchers have long thought that these eels, a type of knifefish, are solitary, nocturnal hunters that use their electric sense to find smaller fish as they sleep (SN: 12/4/14). But in a remote region of the Amazon, groups of over 100 electric eels (Electrophorus voltai) hunt together, corralling thousands of smaller fish together to concentrate, shock and devour the prey, researchers report January 14 in Ecology and Evolution. “This is hugely unexpected,” says Raimundo Nonato Mendes-Júnior, a biologist at the Chico Mendes Institute for Biodiversity Conservation in Brasilia, Brazil who wasn’t involved in the study. “It goes to show how very, very little we know about how electric eels behave in the wild.” Group hunting is quite rare in fishes, says Carlos David de Santana, an evolutionary biologist at the Smithsonian’s National Museum of Natural History in Washington, D.C. “I’d never even seen more than 12 electric eels together in the field,” he says. That’s why he was stunned in 2012 when his colleague Douglas Bastos, now a biologist at the National Institute of Amazonian Research in Manaus, Brazil, reported seeing more than 100 eels congregating and seemingly hunting together in a small lake in northern Brazil. © Society for Science & the Public 2000–2021.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27647 - Posted: 01.15.2021

By Isabella Backman Even tough male chimps need their moms. Chimpanzees live in a male-dominated society, where most of their valuable allies are other males. However, as young male chimpanzees become adults, they continue to maintain tight bonds with their mothers, a new study reveals. And for about one-third of them, this mother-son relationship is the closest one they have. The dramatic changes of adolescence are difficult for chimps, just like they are for humans, says Elizabeth Lonsdorf, a primatologist at Franklin & Marshall College who was not involved in the study. And “sure enough,” she says, “their moms remain a key social partner during this turbulent time.” Previous research has shown chimpanzee mothers provide their sons support that goes far beyond nursing. Young male chimps that are close with their moms grow bigger and have a greater chance of survival. What’s more, losing their mothers after weaning, but before age 12, hinders the ability of young chimps to compete with other males and reproduce. To see whether this bond extends later into life, researchers followed 29 adolescent (9 to 15 years old) and young adult (16 to 20 years old) male chimpanzees at a research site in Kibale National Park in Uganda. For 3 years, they observed the chimps from a distance, recording any social interaction they witnessed. These included grooming, comforting behaviors such as holding hands or shoulder pats, looking back for or waiting for other individuals, offering support during conflicts, and sitting near each other. © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 27633 - Posted: 12.22.2020

By Bruce Bower Bonobos display responsibility toward grooming partners akin to that of people working together on a task, a new study suggests. Until now, investigations have shown only that humans can work jointly toward a common goal presumed to require back-and-forth exchanges and an appreciation of being obligated to a partner (SN: 10/5/09). Primate biologist Raphaela Heesen of Durham University in England and colleagues studied 15 of the endangered great apes at a French zoological park. The researchers interrupted 85 instances of social grooming, in which one ape cleaned another’s fur, and 26 instances of self-grooming or solitary play. Interruptions consisted either of a keeper calling one bonobo in a grooming pair to come over for a food reward or a keeper rapidly opening and closing a sliding door to an indoor enclosure, which typically signaled mealtime and thus attracted both bonobos. Social grooming resumed, on average, 80 percent of the time after food rewards and 83 percent of the time after sliding-door disruptions, the researchers report December 18 in Science Advances. In contrast, self-grooming or playing alone was resumed only around 50 percent of the time, on average. © Society for Science & the Public 2000–2020

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 27629 - Posted: 12.19.2020

By Veronique Greenwood Some 230 million years ago, in the forests of what humans would eventually call Brazil, a small bipedal dinosaur zipped after its prey. It had a slender head, a long tail and sharp teeth, and it was about the size of a basset hound. Buriolestes schultzi, as paleontologists have named the creature, is one of the earliest known relatives of more famous dinosaurs that emerged 100 million years later: the lumbering brachiosaurus, up to 80 feet long and weighing up to 80 metric tons, the likewise massive diplodocus, as well as other sauropod dinosaurs. By the time the Jurassic period rolled around and the time of Buriolestes had passed, these quadrupedal cousins had reached tremendous size. They also had tiny brains around the size of a tennis ball. Buriolestes’s brain was markedly different, scientists who built a 3-D reconstruction of the inside of its skull report in a paper published Tuesday in the Journal of Anatomy. The brain was larger relative to its body size, and it had structures that were much more like those of predatory animals. The findings suggest that the enormous herbivores of later eras, whose ancestors probably looked a lot like Buriolestes, lost these features as they transitioned to their ponderous new lifestyle. It’s also a rare glimpse into dinosaurs’ neural anatomy at a very early moment in their evolution. In 2009, Rodrigo Müller of the Universidade Federal de Santa Maria and colleagues discovered the first partial Buriolestes fossil in southern Brazil. In 2015, they uncovered another Buriolestes nearby — and this time, to their excitement, the dinosaur’s skull was nearly all there. They used computed tomography scanning to get a peek inside, drawing inferences about the brain from the contours of the cavity left behind. They found that one portion of the cerebellum, the floccular lobe, was particularly large in Buriolestes. © 2020 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27566 - Posted: 11.04.2020

By Bruce Bower A type of bone tool generally thought to have been invented by Stone Age humans got its start among hominids that lived hundreds of thousands of years before Homo sapiens evolved, a new study concludes. A set of 52 previously excavated but little-studied animal bones from East Africa’s Olduvai Gorge includes the world’s oldest known barbed bone point, an implement probably crafted by now-extinct Homo erectus at least 800,000 years ago, researchers say. Made from a piece of a large animal’s rib, the artifact features three curved barbs and a carved tip, the team reports in the November Journal of Human Evolution. Among the Olduvai bones, biological anthropologist Michael Pante of Colorado State University in Fort Collins and colleagues identified five other tools from more than 800,000 years ago as probable choppers, hammering tools or hammering platforms. The previous oldest barbed bone points were from a central African site and dated to around 90,000 years ago (SN: 4/29/95), and were assumed to reflect a toolmaking ingenuity exclusive to Homo sapiens. Those implements include carved rings around the base of the tools where wooden shafts were presumably attached. Barbed bone points found at H. sapiens sites were likely used to catch fish and perhaps to hunt large land prey. The Olduvai Gorge barbed bone point, which had not been completed, shows no signs of having been attached to a handle or shaft. Ways in which H. erectus used the implement are unclear, Pante and his colleagues say. © Society for Science & the Public 2000–2020.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27543 - Posted: 10.24.2020

By Meagan Cantwell Although bird brains are tiny, they’re packed with neurons, especially in areas responsible for higher level thinking. Two studies published last month in Science explore the structure and function of avian brains—revealing they are organized similarly to mammals’ and are capable of conscious thought. © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27541 - Posted: 10.24.2020

By Jake Buehler Naked mole-rats — with their subterranean societies made up of a single breeding pair and an army of workers — seem like mammals trying their hardest to live like insects. Nearly 300 of the bald, bucktoothed, nearly blind rodents can scoot along a colony’s labyrinth of tunnels. New research suggests there’s brute power in those numbers: Like ants or termites, the mole-rats go to battle with rival colonies to conquer their lands. Wild naked mole-rats (Heterocephalus glaber) will invade nearby colonies to expand their territory, sometimes abducting pups to incorporate them into their own ranks, researchers report September 28 in the Journal of Zoology. This behavior may put smaller, less cohesive colonies at a disadvantage, potentially supporting the evolution of bigger colonies. Researchers stumbled across this phenomenon by accident while monitoring naked mole-rat colonies in Kenya’s Meru National Park. The team was studying the social structure of this extreme form of group living among mammals (SN: 6/20/06). Over more than a decade, the team trapped and marked thousands of mole-rats from dozens of colonies by either implanting small radio-frequency transponder chips under their skin, or clipping their toes. One day in 1994, while marking mole-rats in a new colony, researchers were surprised to find in its tunnels mole-rats from a neighboring colony that had already been marked. The queen in the new colony had wounds on her face from the ravages of battle. It looked like a war was playing out down in the soil. © Society for Science & the Public 2000–2020.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27538 - Posted: 10.21.2020

By Bret Stetka With enough training, pigeons can distinguish between the works of Picasso and Monet. Ravens can identify themselves in a mirror. And on a university campus in Japan, crows are known to intentionally leave walnuts in a crosswalk and let passing traffic do their nut cracking. Many bird species are incredibly smart. Yet among intelligent animals, the “bird brain” often doesn’t get much respect. Two papers published today in Science find birds actually have a brain that is much more similar to our complex primate organ than previously thought. For years it was assumed that the avian brain was limited in function because it lacked a neocortex. In mammals, the neocortex is the hulking, evolutionarily modern outer layer of the brain that allows for complex cognition and creativity and that makes up most of what, in vertebrates as a whole, is called the pallium. The new findings show that birds’ do, in fact, have a brain structure that is comparable to the neocortex despite taking a different shape. It turns out that at a cellular level, the brain region is laid out much like the mammal cortex, explaining why many birds exhibit advanced behaviors and abilities that have long befuddled scientists. The new work even suggests that certain birds demonstrate some degree of consciousness. The mammalian cortex is organized into six layers containing vertical columns of neurons that communicate with one another both horizontally and vertically. The avian brain, on the other hand, was thought to be arranged into discrete collections of neurons called nuclei, including a region called the dorsal ventricular ridge, or DVR, and a single nucleus named the wulst. In one of the new papers, senior author Onur Güntürkün, a neuroscientist at Ruhr University Bochum in Germany, and his colleagues analyzed regions of the DVR and wulst involved in sound and vision processing. To do so, they used a technology called three-dimensional polarized light imaging, or 3D-PLI—a light-based microscopy technique that can be employed to visualize nerve fibers in brain samples. The researchers found that in both pigeons and barn owls, these brain regions are constructed much like our neocortex, with both layerlike and columnar organization—and with both horizontal and vertical circuitry. They confirmed the 3D-PLI findings using biocytin tracing, a technique for staining nerve cells. © 2020 Scientific American

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27487 - Posted: 09.25.2020

By Elizabeth Preston This is Panurgus banksianus, the large shaggy bee. It lives alone, burrowed into sandy grasslands across Europe. It prefers to feed on yellow-flowered members of the aster family. The large shaggy bee also has a very large brain. Just like mammals or birds, insect species of the same size may have different endowments inside their heads. Researchers have discovered some factors linked to brain size in back-boned animals. But in insects, the drivers of brain size have been more of a mystery. In a study published Wednesday in Proceedings of the Royal Society B, scientists scrutinized hundreds of bee brains for patterns. Bees with specialized diets seem to have larger brains, while social behavior appears unrelated to brain size. That means when it comes to insects, the rules that have guided brain evolution in other animals may not apply. “Most bee brains are smaller than a grain of rice,” said Elizabeth Tibbetts, an evolutionary biologist at the University of Michigan who was not involved in the research. But, she said, “Bees manage surprisingly complex behavior with tiny brains,” making the evolution of bee brains an especially interesting subject. Ferran Sayol, an evolutionary biologist at University College London, and his co-authors studied those tiny brains from 395 female bees belonging to 93 species from across the United States, Spain and the Netherlands. Researchers beheaded each insect and used forceps to remove its brain, a curled structure that’s widest in the center. “It reminds me a little bit of a croissant,” Dr. Sayol said. One pattern that emerged was a connection between brain size and how long each bee generation lasted. Bees that only go through one generation each year have larger brains, relative to their body size, than bees with multiple generations a year. © 2020 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27476 - Posted: 09.16.2020

Primatologists observed that different groups of bonobos have different dietary preferences — indicating a form of "culture" among the animals. AILSA CHANG, HOST: Bonobos, like chimpanzees, are one of our closest living relatives. We share about 99% of our DNA. These endangered apes are covered in incredibly black hair. LIRAN SAMUNI: And what's very nice is that they have extremely pink lips, almost as if they put the lipstick on. SACHA PFEIFFER, HOST: That's Liran Samuni, a primatologist at Harvard University. Now her team has discovered that wild bonobos share more than just DNA with humans and chimps. They also appear to share our penchant for culture. SAMUNI: We already had some information about chimpanzees that they have the ability for culture. But it was always this kind of a puzzle about bonobos. CHANG: So for more than four years, the researchers tracked two bonobo groups in the Democratic Republic of Congo, documenting the apes' social interactions and what they hunted. And they found a striking dietary difference. SAMUNI: So we had one group which specialized on the hunting of a small antelope called duiker, while the other bonobo group specialized on the hunting of anomalure, which is a gliding rodent. PFEIFFER: Samuni says think about it in the context of humans. You might have two cultures living near or among each other, but one prefers chicken; the other prefers beef. CHANG: Samuni's colleague at Harvard Martin Surbeck says that's important because it shows that the two groups of bonobos have different preferences despite their overlapping range. © 2020 npr

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 27465 - Posted: 09.12.2020

By Priyanka Runwal Everyone needs to cool off on a scorching summer day, even chimpanzees. Where do the primates go on sizzling days when woodlands and forests don’t provide respite from the heat? But not just any chimps. New research shows that on Senegal’s savannas, home to a population of chimpanzees that has long fascinated scientists for their distinct behaviors, you’re more likely to find mama chimps than adult males or non-lactating females hiding out in cool caves. Their visits coincided with the hottest times of day and became more frequent during the hottest months of the year, according to the study published last month in the International Journal of Primatology. They also made these visits despite the risks of encounters with predators, showing how important the locations are for helping them survive and bring up babies in a challenging landscape that is threatened by human activities. In southeastern Senegal, temperatures spike to 110 degrees Fahrenheit and fires burn large parts of the landscape over a seven-month dry season. Several natural cave formations pock the terrain, and they can be up to 55 degrees cooler than the surrounding grasslands. The region is also home to the northernmost population of western chimpanzees, a critically endangered subspecies that mostly lives in large swathes of open grasslands and woodlands in this area. In 2001, Jill Pruetz, a primatologist then at Iowa State University, gathered evidence of western chimpanzees using caves in the area, suspecting that they used them to escape the heat and possibly avoid heat stroke and other ill health effects of the dry season. But she reached few conclusions about whether all of the chimps used the caves as often as others. Kelly Boyer Ontl, a primatologist at Ball State University in Indiana and lead author of the new study, said, “I was really interested in finding out what chimpanzees are doing in caves, when are they using it and who’s going in there.” © 2020 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 27409 - Posted: 08.08.2020

By Amanda Heidt Human beings typically don’t leave the nest until well into our teenage years—a relatively rare strategy among animals. But corvids—a group of birds that includes jays, ravens, and crows—also spend a lot of time under their parents’ wings. Now, in a parallel to humans, researchers have found that ongoing tutelage by patient parents may explain how corvids have managed to achieve their smarts. Corvids are large, big-brained birds that often live in intimate social groups of related and unrelated individuals. They are known to be intelligent—capable of using tools, recognizing human faces, and even understanding physics—and some researchers believe crows may rival apes for smarts. Meanwhile, humans continue to grow their big brains and build up their cognitive abilities during childhood, as their parents feed and protect them. “Humans are characterized by this extended childhood that affects our intelligence, but we can’t be the only ones,” says Natalie Uomini, a cognitive scientist at the Max Planck Institute for the Science of Human History. But few researchers have studied the impact of parenting throughout the juvenile years on intelligence in nonhumans. To study the link between parental care and intelligence in birds, Uomini and her team created a database detailing the life history of thousands of species, including more than 120 corvids. Compared with other birds, they found corvids spend more time in the nest before fledging, more days feeding their offspring as adults, and more of their life living among family. The results, reported last week in the Philosophical Transactions of the Royal Society B, also confirm corvids have unusually large brains compared with many other birds. Birds need to be light for flight, but a raven’s brain accounts for almost 2% of its body mass, a value similar to humans. © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27295 - Posted: 06.09.2020

By Ann Gibbons If you think you got your freckles, red hair, or even narcolepsy from a Neanderthal in your family tree, think again. People around the world do carry traces of Neanderthals in their genomes. But a study of tens of thousands of Icelanders finds their Neanderthal legacy had little or no impact on most of their physical traits or disease risk. Paleogeneticists realized about 10 years ago that most Europeans and Asians inherited 1% to 2% of their genomes from Neanderthals. And Melanesians and Australian Aboriginals get another 3% to 6% of their DNA from Denisovans, Neanderthal cousins who ranged across Asia 50,000 to 200,000 years ago or so. A steady stream of studies suggested gene variants from these archaic peoples might raise the risk of depression, blood clotting, diabetes, and other disorders in living people. The archaic DNA may also be altering the shape of our skulls; boosting our immune systems; and influencing our eye color, hair color, and sensitivity to the Sun, according to scans of genomic and health data in biobanks and medical databases. But the new study, which looked for archaic DNA in living Icelanders, challenges many of those claims. Researchers from Aarhus University in Denmark scanned the full genomes of 27,566 Icelanders in a database at deCODE Genetics in Iceland, seeking unusual archaic gene variants. The researchers ended up with a large catalog of 56,000 to 112,000 potentially archaic variants—and a few surprises. They found, for example, that Icelanders had inherited 3.3% of their archaic DNA from Denisovans and 12.2% from unknown sources. (84.5% came from close relatives of the reference Neanderthals.) © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 27211 - Posted: 04.24.2020

Peter Rhys-Evans For the past 150 years, scientists and laypeople alike have accepted a “savanna” scenario of human evolution. The theory, primarily based on fossil evidence, suggests that because our ancestral ape family members were living in the trees of East African forests, and because we humans live on terra firma, our primate ancestors simply came down from the trees onto the grasslands and stood upright to see farther over the vegetation, increasing their efficiency as hunter-gatherers. In the late 19th century, anthropologists only had a few Neanderthal fossils to study, and science had very little knowledge of genetics and evolutionary changes. So this savanna theory of human evolution became ingrained in anthropological dogma and has remained the established explanation of early hominin evolution following the genetic split from our primate cousins 6 million to 7 million years ago. But in 1960, a different twist on human evolution emerged. That year, marine biologist Sir Alister Hardy wrote an article in New Scientist suggesting a possible aquatic phase in our evolution, noting Homo sapiens’s differences from other primates and similarities to other aquatic and semi-aquatic mammals. In 1967, zoologist Desmond Morris published The Naked Ape, which explored different theories about why modern humans lost their fur. Morris mentioned Hardy’s “aquatic ape” hypothesis as an “ingenious” theory that sufficiently explained “why we are so nimble in the water today and why our closest living relatives, the chimpanzees, are so helpless and quickly drown.” © 1986–2020 The Scientist

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Link ID: 27190 - Posted: 04.15.2020