Links for Keyword: Evolution

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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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27190 - Posted: 04.15.2020

By Alexandra Horowitz Recently, in communities under quarantine or stay-at-home orders, residents have looked out their windows to find wild animals that usually stay on the fringes of the city or emerge only at night suddenly appearing in daylight in the middle of the street. The reason is us: Human activity disturbs animals. Even our presence — simply observing, as bird-watchers, or field biologists, or nature-loving hikers — changes their behavior. The ecologist Carl Safina (author of “Beyond Words” and “Song for the Blue Ocean”) is no agnostic observer. He sees humans as destroying the world for nonhuman animals, to say nothing of destroying the animals themselves, and would like us to stop, please. The question for him, and for anyone with this conviction, is: Short of quarantining the human race, what’s the best way to do this? Fifty years ago, the biologist Robert Payne first eavesdropped on a humpback whale community and heard whale song. He spread the word about their ethereal, beautiful forms of communication, and the world looked at whales differently. Since that time, whaling has sharply declined. Today, many advocates for animals appeal to species’ cognitive abilities to argue for their better treatment. They’re so smart or humanlike, the argument goes, we should be treating them better. Such is the vestige of the scala naturae that has awarded all lives a certain value — with humans on top, of course. © 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: 27185 - Posted: 04.14.2020

Amy Schleunes The brains of Australopithecus afarensis, a hominin species that lived in eastern Africa more than 3 million years ago, were organized in a manner similar to those of apes, report the authors of a study published on April 1 in Science Advances, but they also indicate a slow growth period like that found in modern humans. “The fact that protracted brain growth emerged in hominins as early as 3.3 Ma ago could suggest that it characterized all of subsequent hominin evolutionary history,” the authors write in the paper, though brain development patterns in hominins may not have followed a linear trajectory in the evolutionary process that led to modern humans. Whatever the evolutionary pattern, they say, the extended brain growth period in A. afarensis “provided a basis for subsequent evolution of the brain and social behavior in hominins and was likely critical for the evolution of a long period of childhood learning.” P. Gunz et al., “Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth,” Science Advances, doi:10.1126/sciadv.aaz4729, 2020. © 1986–2020 The Scientist

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27177 - Posted: 04.10.2020

By Bruce Bower Lucy’s kind had small, chimplike brains that, nevertheless, grew at a slow, humanlike pace. This discovery, reported April 1 in Science Advances, shows for the first time that prolonged brain growth in hominid youngsters wasn’t a by-product of having unusually large brains. An influential idea over the last 20 years has held that extended brain development after birth originated in the Homo genus around 2.5 million years ago, so that mothers — whose pelvic bones and birth canal had narrowed to enable efficient upright walking — could safely deliver babies. But Australopithecus afarensis, an East African hominid species best known for Lucy’s partial skeleton, also had slow-developing brains that reached only about one-third the volume of present-day human brains, say paleoanthropologist Philipp Gunz of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues. And A. afarensis is roughly 3 million to 4 million years old, meaning slow brain growth after birth developed before members of the Homo genus appeared, perhaps as early as 2.8 million years ago (SN: 3/4/15). Too few A. afarensis infants have been studied to calculate the age at which this species attained adult-sized brains, Gunz cautions. The brains of human infants today reach adult sizes by close to age 5, versus an age of around 2 or 3 for both chimps and gorillas. In the new study, Gunz and colleagues estimated brain volumes for six A. afarensis adults and two children, estimated to have been about 2 years and 5 months old. The kids had brains that were smaller than adult A. afarensis brain sizes in a proportion similar to human children’s brains at the same age relative to adult humans. © Society for Science & the Public 2000–2020.

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: 27163 - Posted: 04.02.2020

By Virginia Morell Whether it’s calculating your risk of catching the new coronavirus or gauging the chance of rain on your upcoming beach vacation, you use a mix of statistical, physical, and social information to make a decision. So do New Zealand parrots known as keas, scientists report today. It’s the first time this cognitive ability has been demonstrated outside of apes, and it may have implications for understanding how intelligence evolved. “It’s a neat study,” says Karl Berg, an ornithologist and parrot expert at the University of Texas Rio Grande Valley, Brownsville, who was not involved with this research. Keas already had a reputation in New Zealand—and it wasn’t a great one. The olive-brown, crow-size birds can wield their curved beaks like knives—and did so on early settlers’ sheep, slicing through wool and muscle to reach the fat along their spines. These days, they’re notorious for slashing through backpacks for food and ripping windshield wipers off cars. To see whether keas’ intelligence extended beyond being mischievous, Amalia Bastos, a doctoral candidate in comparative psychology at the University of Auckland, and colleagues turned to six captive keas at a wildlife reserve near Christchurch, New Zealand. The researchers taught the birds that a black token always led to a tasty food pellet, whereas an orange one never did. When the scientists placed two transparent jars containing a mix of tokens next to the keas and removed a token with a closed hand, the birds were more likely to pick hands dipped into jars that contained more black than orange tokens, even if the ratio was as close as 63 to 57. That experiment combined with other tests “provide conclusive evidence” that keas are capable of “true statistical inference,” the scientists report in today’s issue of Nature Communications. © 2020 American Association for the Advancement of Science

Related chapters from BN: Chapter 18: Attention and Higher Cognition; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 14: Attention and Higher Cognition
Link ID: 27092 - Posted: 03.04.2020

By Veronique Greenwood When you look at a reconstruction of the skull and brain of Neoepiblema acreensis, an extinct rodent, it’s hard to shake the feeling that something’s not quite right. Huddled at the back of the cavernous skull, the brain of the South American giant rodent looks really, really small. By some estimates, it was around three to five times smaller than scientists would expect from the animal’s estimated body weight of about 180 pounds, and from comparisons to modern rodents. In fact, 10 million years ago the animal may have been running around with a brain weighing half as much as a mandarin orange, according to a paper published Wednesday in Biology Letters. The glory days of rodents, in terms of the animals’ size, were quite a long time ago, said Leonardo Kerber, a paleontologist at Universidade Federal de Santa Maria in Brazil and an author of the new study. Today rodents are generally dainty, with the exception of larger creatures like the capybara that can weigh as much as 150 pounds. But when it comes to relative brain size, N. acreensis, represented in this study by a fossil skull unearthed in the 1990s in the Brazilian Amazon, seems to be an extreme. The researchers used an equation that relates the body and brain weight of modern South American rodents to get a ballpark estimate for N. acreensis, then compared that with the brain weight implied by the volume of the cavity in the skull. The first method predicted a brain weighing about 4 ounces, but the volume suggested a dinky 1.7 ounces. Other calculations, used to compare the expected ratio of the rodent’s brain and body size with the actual fossil, suggested that N. acreensis’ brain was three to five times smaller than one would expect. © 2020 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27035 - Posted: 02.13.2020

Kristen S. Morrow Human beings used to be defined as “the tool-maker” species. But the uniqueness of this description was challenged in the 1960s when Dr. Jane Goodall discovered that chimpanzees will pick and modify grass stems to use to collect termites. Her observations called into question homo sapiens‘ very place in the world. Since then scientists’ knowledge of animal tool use has expanded exponentially. We now know that monkeys, crows, parrots, pigs and many other animals can use tools, and research on animal tool use changed our understanding of how animals think and learn. Studying animal tooling – defined as the process of using an object to achieve a mechanical outcome on a target – can also provide clues to the mysteries of human evolution. Our human ancestors’ shift to making and using tools is linked to evolutionary changes in hand anatomy, a transition to walking on two rather than four feet and increased brain size. But using found stones as pounding tools doesn’t require any of these advanced evolutionary traits; it likely came about before humans began to manufacture tools. By studying this percussive tool use in monkeys, researchers like my colleagues and I can infer how early human ancestors practiced the same skills before modern hands, posture and brains evolved. Understanding wild animals’ memory, thinking and problem-solving abilities is no easy task. In experimental research where animals are asked to perform a behavior or solve a problem, there should be no distractions – like a predator popping up. But wild animals come and go as they please, over large spaces, and researchers cannot control what is happening around them. © 2010–2020, The Conversation US, Inc.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26947 - Posted: 01.10.2020

By Eva Frederick One day in 2014, primatologist Yuko Hattori was trying to teach a mother chimpanzee in her lab to keep a beat. Hattori would play a repetitive piano note, and the chimp would attempt to tap out the rhythm on a small electronic keyboard in hopes of receiving a tasty piece of apple. Everything went as expected in the experiment room, but in the next room over, something strange was happening. Another chimpanzee, the mother’s son, heard the beat and began to sway his body back and forth, almost as if he were dancing. “I was shocked,” Hattori says. “I was not aware that without any training or reward, a chimpanzee would spontaneously engage with the sound.” Hattori has now published her research showing that chimps respond to sounds, both rhythmic and random, by “dancing.” “This study is very thought-provoking,” says Andrea Ravignani, a cognitive biologist at the Seal Rehabilitation and Research Centre who researches the evolution of rhythm, speech, and music. The work, she says, could shed light on the evolution of dancing in humans. For their the study, Hattori and her colleague Masaki Tomonaga at Kyoto University played 2-minute clips of evenly spaced, repetitive piano tones (heard in the video above) to seven chimpanzees (three males and four females). On hearing the sound, the chimps started to groove, swaying back and forth and sometimes tapping their fingers or their feet to the beat or making howling “singing” sounds, the researchers report today in the Proceedings of the National Academy of Sciences. All of the chimps showed at least a little bit of rhythmic movement, though the males spent much more time moving to the music than females. © 2019 American Association for the Advancement of Science.

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: 26916 - Posted: 12.26.2019

By Bruce Bower Homo erectus, a humanlike species that dispersed from Africa into parts of Europe and Asia roughly 2 million years ago, eventually reached the Indonesian island of Java before dying out. Scientists say they have now resolved a controversy over just how long ago the last known H. erectus inhabited the Southeast Asian island. New evidence narrows the timing of this hominid’s final stand on Java to between 117,000 and 108,000 years ago, says a team led by geochronologists Yan Rizal of Indonesia’s Bandung Institute of Technology and Kira Westaway of Macquarie University in Sydney. The scientists present their results December 18 in Nature. If the findings hold up to scrutiny, the fossils would be the last known occurrence of H. erectus anywhere in the world, and would show that the hominid was part of a complex interplay among different Homo species in Southeast Asia that started more than 100,000 years ago. Excavations at Java’s Ngandong site from 1931 to 1933 uncovered 12 skullcaps and two lower leg bones from H. erectus. Since then, uncertainty about how Ngandong sediment layers formed and confusion about the original location of the excavated fossils has led to dramatically contrasting age estimates for the finds. A 1996 report in Science dated the Ngandong specimens to between 53,000 and 27,000 years ago, suggesting that H. erectus had lived alongside Homo sapiens in Indonesia (SN: 12/14/96). But a more recent analysis greatly increased the estimated age of the Java fossils, dating them to around 550,000 years ago (SN: 4/16/10). © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26905 - Posted: 12.19.2019

By Bruce Bower An ancient ape that was larger than a full-grown male gorilla has now revealed molecular clues to its evolutionary roots. Proteins extracted from a roughly 1.9-million-year-old tooth of the aptly named Gigantopithecus blacki peg it as a close relative of modern orangutans and their direct ancestors, say bioarchaeologist Frido Welker of the University of Copenhagen and his colleagues. Protein comparisons among living and fossil apes suggest that Gigantopithecus and orangutan forerunners diverged from a common ancestor between around 10 million and 12 million years ago, Welker’s group reports November 13 in Nature. Since it was first described in 1935, based on a molar purchased from a traditional Chinese drugstore in Hong Kong, G. blacki has stimulated debate over its evolutionary links to other ancient apes. Almost 2,000 isolated teeth and four partial jaws of G. blacki have since been found in southern China and nearby parts of Southeast Asia. G. blacki fossils date from around 2 million to almost 300,000 years ago. The sizes of individual teeth and jaws indicate that G. blacki weighed between 200 and 300 kilograms. Proteins preserve better in teeth and bones than DNA does, but both molecular forms break down quickly in hot, humid settings. “We were surprised to find any proteins this old at all, especially in a fossil from a subtropical environment,” Welker says. Proteins consisting of chains of amino acids can be used to sort out living and fossil species of various animals, including hominids (SN: 5/1/19). © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26818 - Posted: 11.14.2019

By Karinna Hurley Part of the Museum of Natural History in Paris, the Jardin des Plantes, on the left bank of the Seine River, hosts a collection of galleries and gardens. A couple of miles away, the larger museum also includes the Museum of Mankind, which is, in part, an exploration of what it means to be human. There, like in many other museums worldwide, you can view a collection of stone tools used by the earliest humans. Tool use was long believed to be unique to our species—a defining feature, like language. Utilizing objects to achieve goals is not just a demonstration of advanced cognitive capabilities; it is largely through our symbolic and material tools that we share and transmit culture. In 1960 primatologist Jane Goodall observed wild chimpanzees making and using tools. A connection between humans and other animals, in how we think and learn, was captivating news. Since then, scientists have gone on to establish tool use in a relatively small number of other species. And observations of learning to use a tool from other group members, rather than instinctively, have been even more rare—until now. The Jardin des Plantes is also home to a special couple, Priscilla and Billie. Along with at least one of their daughters, these Visayan warty pigs—residents of the garden’s zoo—are the first in any pig species to be identified using tools and, even more remarkably, to apparently transmit this behavior through social learning. The discovery was made by chance by ecologist Meredith Root-Bernstein, who was watching the family from outside its enclosure. Priscilla, working on building a nest, picked up a piece of bark in her mouth and used it to aid her digging. For six weeks Root-Bernstein frequently returned to the zoo to try to again catch her in the act. Although she didn’t do so, she did notice the digging tool moved among different areas of the enclosure and always near a recently constructed nest. © 2019 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: 26817 - Posted: 11.14.2019

By Elizabeth Preston A pack of baldheaded, boldly plumaged birds steps through the grass shoulder to shoulder, red eyes darting around. They look like middle schoolers seeking a cafeteria table at lunchtime. Perhaps they’re not so different. A study published Monday in Current Biology shows that the vulturine guineafowl of eastern Africa, like humans, have many-layered societies. In the past, scientists hypothesized that such social structures require a lot of brainpower. But the pea-brained guineafowl are revealing the flaws in that assumption. Damien Farine, who led the research and is an ornithologist at the Max Planck Institute of Animal Behavior who studies collective behavior, first worked in Kenya during his postdoctoral research on baboon societies. Baboons are a model for researchers trying to understand how human society evolved. Some kinds of baboons live in groups within groups, a structure that’s called a multilevel society. “Humans are the classic multilevel society,” Dr. Farine said. Imagine a human family living in a village: The family might be friendly with other families within the village, which in turn might have ties to neighboring villages, and so on. “People have long hypothesized that living in complex society is one of the reasons why we’ve evolved such large brains,” Dr. Farine said. Researchers have found evidence for multilevel societies in some other large-brained mammals, such as monkeys, elephants, giraffes and sperm whales. But as Dr. Farine studied baboons, he also watched the vulturine guineafowl wandering around his study site. “I was really struck by the social behavior that they exhibited,” he said. These hefty birds can fly, but rarely choose to. Instead, they stroll across the landscape in packs, often walking so closely that their bodies touch. They may chase each other or fight to maintain their strict hierarchies. But at other times they engage in friendly behaviors like sharing food. Their groups are unusually large for birds, sometimes including 60 or more individuals. And while most other social birds are very territorial, Dr. Farine says, groups of vulturine guineafowl don’t mind sharing turf. © 2019 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26789 - Posted: 11.05.2019

By Carl Zimmer Evolutionary biologists retrace the history of life in all its wondrous forms. Some search for the origin of our species. Others hunt for the origin of birds. On Thursday, a team of researchers reported an important new insight into the origin of zombies — in this case, ants zombified by a fungus. Here’s how it works: Sometimes an ant, marching about its business outdoors, will step on a fungal spore. It sticks to the ant’s body and slips a fungal cell inside. The fungus, called Ophiocordyceps, feeds on the ant from within and multiplies into new cells. But you wouldn’t know it, because the ant goes on with its life, foraging for food to bring back to the nest. All the while, the fungus keeps growing until it makes up nearly half of the ant’s body mass. When Ophiocordyceps is finished feeding on its host, the fungal cells gather inside the ant’s body. They form a mat and push needlelike projections into the ant’s muscle cells. The fungal cells also send chemical signals to the ant’s brain, causing the host to do something strange. The ant departs its nest and climbs a nearby plant. In the tropics, where many species of Ophiocordyceps live, the fungus drives ants upward, to a leaf above the ground. The ant bites down, its jaws locking as it dies. The fungus sends out sticky threads that glue the corpse to the leaf. And now it is ready to take the next step in its life cycle: Out of the ant’s head bursts a giant stalk, which showers spores onto the ant trails below. “The ants are walking over a minefield,” said David Hughes, an expert on Ophiocordyceps at Pennsylvania State University. © 2019 The New York Times Company

Related chapters from BN: Chapter 1: Introduction: Scope and Outlook; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 20:
Link ID: 26754 - Posted: 10.25.2019

Tara Boyle Some of Laurie Santos's most insightful research was sparked by an embarrassing incident. One day, monkeys — her research subjects — stole all the fruit she needed to run a study. She left the research site early for the day. On the boat ride home from Cayo Santiago, the island where the monkeys lived, Santos reflected on the monkeys' mischief. "It's not just that we're dumb researchers and they can outsmart us," she says. "They're specifically trying to steal from us when we're not aware of what they're doing." Santos, a professor of psychology at Yale University, decided to study the monkeys' theft. She found that they selectively stole from the person who couldn't see them. "In other words, they're rationally calculating whether or not someone could detect that they're about to do something dastardly," she says. It was behavior befitting a human. Over the years Santos has discovered other similarities in how humans and non-human primates act. She's also pinpointed important differences, helping us understand which capacities are unique to humans. This comparison between humans and other animals, Santos says, is essential for making any claims that humans are unique. "There's no way to study what makes humans special if you only study humans. You actually have to turn to all the other critters in the animal kingdom," she says. © 2019 npr

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26739 - Posted: 10.23.2019

By Rachel Nuwer In the perennial battle over dogs and cats, there’s a clear public relations winner. Dogs are man’s best friend. They’re sociable, faithful and obedient. Our relationship with cats, on the other hand, is often described as more transactional. Aloof, mysterious and independent, cats are with us only because we feed them. Or maybe not. On Monday, researchers reported that cats are just as strongly bonded to us as dogs or infants, vindicating cat lovers across the land. “I get that a lot — ‘Well, I knew that, I know that cats like to interact with me,’” said Kristyn Vitale, an animal behavior scientist at Oregon State University and lead author of the new study, published in Current Biology. “But in science, you don’t know that until you test it.” Research into cat behavior has lagged that into dogs. Cats are not social animals, many scientists assumed — and not as easy to work with. But recent studies have begun to plumb the depth of cats’ social lives. “This idea that cats don’t really care about people or respond to them isn’t holding up,” Ms. Vitale said. In a study in 2017, Ms. Vitale and her colleagues found that the majority of cats prefer interacting with a person over eating or playing with a toy. In a 2019 study, the researchers found that cats adjust their behavior according to how much attention a person gives them. Other researchers have found that cats are sensitive to human emotion and mood, and that cats know their names. Scientists had arrived at conflicting findings about whether cats form attachments to their owners, however, so Ms. Vitale and her colleagues designed a study to more explicitly test the hypothesis. They recruited owners of 79 kittens and 38 adult cats to participate in a “secure base test,” an experiment commonly used to measure bonds that dogs and primates form with caretakers. © 2019 The New York Times Company

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 26647 - Posted: 09.25.2019