By Roberta McLain Two small genetic changes reshaped the human pelvis, setting our early ancestors on the path to upright walking, scientists say. One genetic change flipped the ilium — the bone your hands rest on when you put them on your hips — 90 degrees. The rotation reoriented the muscles that attach to the pelvis, turning a system for climbing and running on all four legs into one for standing and walking on two legs. The other change delayed how long it takes for the ilium to harden from soft cartilage into bone, evolutionary biologist Gayani Senevirathne of Harvard University and colleagues report in the Sept. 25 Nature. The result: a distinctive bowl-shaped pelvis that supports an upright body. While nonhuman primates can walk upright to some extent, they typically move on all fours. The newly identified changes to human pelvic development were “essential for creating and shifting muscles that are usually on the back of the animal, pushing the animal forward, to now being on the sides, helping us stay upright as we walk,” says coauthor Terence Capellini, a Harvard evolutionary biologist. The researchers examined tiny slices of developing pelvic tissue from humans, chimpanzees and mice under a microscope, and paired those findings with CT imaging. Human ilium cartilage grows sideways, not vertically as it does in other primates, the team found. What’s more, the cartilage transitions to bone more slowly than in nonhuman primates and in other human body parts. Together, these shifts allow the pelvis to expand sideways and maintain its wide, bowl-like shape as it grows. © Society for Science & the Public 2000–2025.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 29986 - Posted: 10.29.2025

By Keith Schneider Jane Goodall, one of the world’s most revered conservationists, who earned scientific stature and global celebrity by chronicling the distinctive behavior of wild chimpanzees in East Africa — primates that made and used tools, ate meat, held rain dances and engaged in organized warfare — died on Wednesday in Los Angeles. She was 91. Her death, while on a speaking tour, was confirmed by the Jane Goodall Institute, whose U.S. headquarters are in Washington, D.C. When not traveling widely, she lived in Bournemouth, on the south coast of England, in her childhood home. Dr. Goodall was 29 in the summer of 1963 when National Geographic magazine published her 7,500-word, 37-page account of the lives of primates she had observed in the Gombe Stream Chimpanzee Reserve in what is now Tanzania. The National Geographic Society had been financially supporting her field studies there. The article, with photographs by Hugo van Lawick, a Dutch wildlife photographer whom she later married, also described Dr. Goodall’s struggles to overcome disease, predators and frustration as she tried to get close to the chimps, working from a primitive research station along the eastern shore of Lake Tanganyika. On the scientific merits alone, her discoveries about how wild chimpanzees raised their young, established leadership, socialized and communicated broke new ground and attracted immense attention and respect among researchers. Stephen Jay Gould, the evolutionary biologist and science historian, said her work with chimpanzees “represents one of the Western world’s great scientific achievements.” On learning of Dr. Goodall’s documented evidence that humans were not the only creatures capable of making and using tools, Louis Leakey, the paleoanthropologist and Dr. Goodall’s mentor, famously remarked, “Now we must redefine ‘tool,’ redefine ‘man,’ or accept chimpanzees as humans.” © 2025 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 29953 - Posted: 10.04.2025

By Carl Zimmer Charles Darwin unveiled his theory of evolution in 1859, in “On the Origin of Species.” But it took him another 12 years to work up the courage to declare that humans evolved, too. In “The Descent of Man,” published in 1871, Darwin argued that humans arose from apes. And one of the most profound changes they underwent was turning into upright walkers. “Man alone has become a biped,” Darwin wrote. Bipedalism, he declared, was one of humanity’s “most conspicuous characters.” Scientists have now discovered some of the crucial molecular steps that led to that conspicuous character millions of years ago. A study published in the journal Nature on Wednesday suggests that our early ancestors became bipeds, as old genes started doing new things. Some genes became active in novel places in the human embryo, while others turned on and off at different times. Scientists have long recognized that a key feature for walking upright is a bone called the ilium. It’s the biggest bone in the pelvis; when you put your hand on your hip, that’s the ilium you feel. The left and right ilium are both fused to the base of the spine. Each ilium sweeps around the waist to the front of the belly, creating a bowllike shape. Many of the leg muscles we use in walking are anchored to the ilium. The bone also supports the pelvic floor, a network of muscles that acts like a basket for our inner organs when we stand up. As vital as the ilium is to everyday life, the bone can also be a source of suffering. The ilium can flare up with arthritis, grow brittle in old age, especially in women, and fracture from a fall. Genetic disorders can deform it, making walking difficult. The ilium also forms much of the birth canal — where babies can sometimes get stuck, endangering the mother’s life. © 2025 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: 29906 - Posted: 08.30.2025

Nicola Davis Science correspondent Big hands might mean big feet, but it seems long thumbs are linked to large brains – at least in primates. Researchers say the results suggest the brain co-evolved with manual dexterity in such mammals. “We imagine an evolutionary scenario in which a primate or human has become more intelligent, and with that comes the ability to think about action planning, think about what you are doing with your hands, and realise that actually you are more efficient at doing it one way or another,” said Dr Joanna Baker, lead author of the research from the University of Reading. “And those that have longer thumbs or more ability to manipulate the objects in the way that the mind can see were likely to be more successful.” Large brains and manual dexterity are both thought to have played an important role in human evolution, with opposable thumbs a key feature that enabled a greater ability to grip and manipulate items – including tools. However, with some other primates having partly opposable thumbs, questions have remained over whether other changes in the hand – such as thumb length – could also be important in the evolution of tool use. “In general terms, you can say that the longer the thumb you have, the more motion you have to pick up and control small objects,” said Baker. To explore the issue Baker and colleagues studied the estimated brain mass and thumb length of 94 primate species, from five of our ancient hominin relatives to lemurs. The results, published in the journal Communications Biology, reveal humans and most other hominins have thumbs that are significantly longer than would be predicted based on the hand proportions of primates as a while. However, further analysis revealed an intriguing pattern. “When you have longer thumbs relative to your overall hand, that tends to come in conjunction with overall increased brain size,” said Baker. © 2025 Guardian News & Media Limited

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: 29902 - Posted: 08.27.2025

By Tim Vernimmen Mexican tetras are a most peculiar fish species. They occur in many rivers and lakes across Mexico and southern Texas, where they look perfectly ordinary. But unlike most other fishes, tetras also live in caves. And there, in the absence of light, they look dramatically different: They’re very pale and, remarkably, they lack eyes. Time and again, whenever a population was swept into a cave and survived long enough for natural selection to have its way, the eyes disappeared. “But it’s not that everything has been lost in cavefish,” says geneticist Jaya Krishnan of the Oklahoma Medical Research Foundation. “Many enhancements have also happened.” Though the demise of their eyes continues to fascinate biologists, in recent years attention has shifted to other intriguing aspects of cavefish biology. It has become increasingly clear that they haven’t just lost sight, but also gained many adaptations that help them to thrive in their cave environment, including some that may hold clues to treatments for obesity and diabetes in people. It has long been debated why the eyes were lost. Some biologists used to argue that they just withered away over generations because cave-dwelling animals with faulty eyes experienced no disadvantage. But another explanation is now considered more likely, says evolutionary physiologist Nicolas Rohner of the University of Münster in Germany: “Eyes are very expensive in terms of resources and energy. Most people now agree that there must be some advantage to losing them, if you don’t need them.” Scientists have observed that mutations in different genes involved in eye formation have led to eye loss. In other words, says Krishnan, “different cavefish populations have lost their eyes in different ways.”

Related chapters from BN: Chapter 10: Vision: From Eye to Brain; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 29885 - Posted: 08.13.2025

By Sofia Caetano Avritzer The original paleo diet might have included fewer succulent steaks and more juicy maggots. Neandertals are often depicted at the top of the food chain for their time, consuming as much meat as lions or hyenas. But maggots growing on rotting meat might have been the real signature dish of the Neandertal diet, researchers report July 25 in Science Advances. The idea that Neandertals were extreme carnivores comes partly from the high levels of a specific type of nitrogen called N-15 in their bones. Nitrogen has two stable forms. N-14 is lighter and a lot more common in nature, while N-15 is heavier and much rarer. When an animal eats a plant with both types of nitrogen, it will keep more N-15 than N-14 in its body after digestion. If that animal gets eaten, its predator will have an even higher proportion of N-15. That makes this molecule more prominent in animals that eat a lot of meat, says Melanie Beasley, a biological anthropologist at Purdue University in West Lafayette, Ind. The proportion of N-15 to N-14 found in Neandertal bones is similar to that found in animals like hyenas, which eat almost exclusively meat, Beasley says. But humans can’t consume as much meat as specialized carnivores, says Karen Hardy, a prehistoric archeologist at the University of Glasgow in Scotland. Without a balanced diet, the human body transforms protein into energy instead of using it to develop muscle, hormones and more. This creates toxic waste products that can cause nausea, diarrhea and even death. So, if Neandertals probably couldn’t eat as much meat as lions or hyenas, where does all the N-15 come from? Rotting meat. © Society for Science & the Public 2000–2025.

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: 29866 - Posted: 07.26.2025

By Asher Elbein True friends, most people would agree, are there for each other. Sometimes that means offering emotional support. Sometimes it means helping each other move. And if you’re a superb starling — a flamboyant, chattering songbird native to the African savanna — it means stuffing bugs down the throats of your friends’ offspring, secure in the expectation that they’ll eventually do the same for yours. Scientists have long known that social animals usually put blood relatives first. But for a study published Wednesday in the journal Nature, researchers crunched two decades of field data to show that unrelated members of a superb starling flock often help each other raise chicks, trading assistance to one another over years in a behavior that was not previously known. “We think that these reciprocal helping relationships are a way to build ties,” said Dustin Rubenstein, a professor of ecology at Columbia University and an author of the paper. Superb starlings are distinctive among animals that breed cooperatively, said Alexis Earl, a biologist at Cornell University and an author of the paper. Their flocks mix family groups with immigrants from other groups. New parents rely on up to 16 helpers, which bring chicks extra food and help run off predators. Dr. Rubenstein’s lab has maintained a 20-year field study of the species that included 40 breeding seasons. It has recorded thousands of interactions between hundreds of the chattering birds and collected DNA to examine their genetic relationships. When Dr. Earl, then a graduate student in the lab, began crunching the data, she and her colleagues weren’t shocked to see that birds largely helped relatives, the way an aunt or uncle may swoop in to babysit and give parents a break. © 2025 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Higher Cognition
Link ID: 29780 - Posted: 05.10.2025

By Gayoung Lee edited by Allison Parshall Crows sometimes have a bad rap: they’re said to be loud and disruptive, and myths surrounding the birds tend to link them to death or misfortune. But crows deserve more love and charity, says Andreas Nieder, a neurophysiologist at the University of Tübingen in Germany. They not only can be incredibly cute, cuddly and social but also are extremely smart—especially when it comes to geometry, as Nieder has found. In a paper published on Friday in Science Advances, Nieder and his colleagues report that crows display an impressive aptitude at distinguishing shapes by using geometric irregularities as a cognitive cue. These crows could even discern quite subtle differences. For the experiment, the crows perched in front of a digital screen that, almost like a video game, displayed progressively more complex combinations of shapes. First, the crows were taught to peck at a certain shape for a reward. Then they were presented with that same shape among five others—for example, one star shape placed among five moon shapes—and were rewarded if they correctly picked the "outlier." “Initially [the outlier] was very obvious,” Nieder says. But once the crows appeared to have familiarized themselves with how the “game” worked, Nieder and his team introduced more similar quadrilateral shapes to see if the crows would still be able to identify outliers. “And they could tell us, for instance, if they saw a figure that was just not a square, slightly skewed, among all the other squares,” Nieder says. “They really could do this spontaneously [and] discriminate the outlier shapes based on the geometric differences without us needing them to train them additionally.” Even when the researchers stopped rewarding them with treats, the crows continued to peck the outliers. © 2024 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: 29741 - Posted: 04.12.2025

By Adam Nossiter Ralph Holloway, an anthropologist who pioneered the idea that changes in brain structure, and not just size, were critical in the evolution of humans, died on March 12 at his home in Manhattan. He was 90. His death was announced by Columbia University’s anthropology department, where he taught for nearly 50 years. Mr. Holloway’s contrarian idea was that it wasn’t necessarily the big brains of humans that distinguished them from apes or primitive ancestors. Rather, it was the way human brains were organized. Brains from several million years ago don’t exist. But Dr. Holloway’s singular focus on casts of the interiors of skull fossils, which he usually made out of latex, allowed him to override this hurdle. He “compulsively collected” information from these casts, he wrote in a 2008 paper. Crucially, they offered a representation of the brain’s exterior edges, which allowed scientists to get a sense of the brain’s structure. Using a so-called endocast, Dr. Holloway was able to establish conclusively, for instance, that a famous and controversial two-million-year-old hominid fossil skull from a South Africa limestone quarry, known as the Taung child, belonged to one of mankind’s distant ancestors. The Taung child’s brain was small, leading many to doubt the conclusion of Raymond Dart, the anatomist who discovered it in the 1920s, that it was a human ancestor. In 1969, Dr. Holloway took his family to South Africa to meet the elderly Dr. Dart, to examine the natural limestone endocast that the Taung child’s positioning in the quarry had created and to make an endocast of his own. “I became convinced that the Taung endocast needed independent study,” he wrote in 2008, in order to “find an objective method(s) for deciding whether the cortex was reorganized as Dart had previously claimed,” so many years before. Dr. Holloway focused on a crescent-shaped furrow, called the lunate sulcus, at the back of the endocast. In his view, it was positioned like a human’s, which suggested to him that Dr. Dart had been right all along. © 2025 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 29727 - Posted: 04.05.2025

By Calli McMurray, Angie Voyles Askham, Claudia López Lloreda, Shaena Montanari Neuroscience can sometimes feel like an old mouse club—but it wasn’t always that way. In the 1960s and ’70s, neuroscientists routinely put on their field boots to search for the “animal that was expert at doing the task that you were interested in studying,” says Eve Marder, university professor of biology at Brandeis University. “People studied insects and annelids and mollusks and every kind of animal imaginable. And if they could have studied elephants, they would have.” Many fundamental—and Nobel-prize-winning—discoveries emerged from this approach. Recording from the squid’s giant axon, for example, revealed how action potentials work; experiments in sea slugs illuminated the molecular changes that drive learning and memory; work in barn owls unraveled sound localization; and studies in horseshoe crabs first exposed lateral inhibition in photoreceptors. But by the end of the 20th century, model diversity had fallen out of vogue. A small band of neuroethologists continued to explore animals off the beaten path, but the majority of neuroscientists soon jumped over to standard animal models, Marder says. Many of today’s common model organisms—including the mouse, zebrafish, roundworm and fruit fly—soared in popularity because they are cheap, easy to work with and quick to raise in a lab. The invention of molecular and genetic tools tailored to these species only increased their appeal, as did attention from the U.S. federal government. In 1999, the National Institutes of Health (NIH) published a list of 13 canonical model organisms for biomedical research, and in 2004 the organization’s “road map” encouraged the use of research animals for which genetic tools were available. Now, two decades later, a non-model organism “renaissance” is underway, says Ishmail Abdus-Saboor, associate professor of biological sciences at Columbia University, as a growing number of neuroscientists step outside of the model organism box. This shift is largely due to cost reductions and technological advances in “species-neutral” techniques, says Sam Reiter, assistant professor of computational neuroethology at the Okinawa Institute of Science and Technology, such as high-throughput extracellular recordings, machine-learning-based behavioral tracking, genome and transcriptome sequencing, and gene-editing tools. “This lets researchers quickly reach close to the cutting edge, even if working on an animal where little is known.” © 2024 Simons Foundation

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 29605 - Posted: 12.21.2024

By Sofia Quaglia It’s amazing what chimpanzees will do for a snack. In Congolese rainforests, the apes have been known to poke a hole into the ground with a stout stick, then grab a long stem and strip it through their teeth, making a brush-like end. Into the hole that lure goes, helping the chimps fish out a meal of termites. How did the chimps figure out this sophisticated foraging technique and others? “It’s difficult to imagine that it can just have appeared out of the blue,” said Andrew Whiten, a cultural evolution expert from the University of St. Andrews in Scotland who has studied tool use and foraging in chimpanzees. Now Dr. Whiten’s team has set out to demonstrate that advanced uses of tools are an example of humanlike cultural transmission that has accumulated over time. Where bands of apes in Central and East Africa exhibit such complex behaviors, they say, there are also signs of genes flowing between groups. They describe this as evidence that such foraging techniques have been passed from generation to generation, and innovated over time across different interconnected communities. In a study published on Thursday in the journal Science, Dr. Whiten and colleagues go as far as arguing that chimpanzees have a “tiny degree of cumulative culture,” a capability long thought unique to humans. From mammals to birds to reptiles and even insects, many animals exhibit some evidence of culture, when individuals can socially learn something from a nearby individual and then start doing it. But culture becomes cumulative over time when individuals learn from others, each building on the technique so much that a single animal wouldn’t have been able to learn all of it on its own. For instance, some researchers interpret using rocks as a hammer and anvil to open a nut as something chimpanzees would not do spontaneously without learning it socially. Humans excel at this, with individual doctors practicing medicine each day, but medicine is no one single person’s endeavor. Instead, it is an accumulation of knowledge over time. Most chimpanzee populations do not use a complex set of tools, in a specific sequence, to extract food. © 2024 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: 29573 - Posted: 11.23.2024

By Ann Gibbons As the parent of any teenager knows, humans need a long time to grow up: We take about twice as long as chimpanzees to reach adulthood. Anthropologists theorize that our long childhood and adolescence allow us to build comparatively bigger brains or learn skills that help us survive and reproduce. Now, a study of an ancient youth’s teeth suggests a slow pattern of growth appeared at least 1.8 million years ago, half a million years earlier than any previous evidence for delayed dental development. Researchers used state-of-the art x-ray imaging methods to count growth lines in the molars of a member of our genus, Homo, who lived 1.77 million years ago in what today is Dmanisi, Georgia. Although the youth developed much faster than children today, its molars grew as slowly as a modern human’s during the first 5 years of life, the researchers report today in Nature. The finding, in a group whose brains are hardly larger than chimpanzees, could provide clues to why humans evolved such long childhoods. “One of the main questions in paleoanthropology is to understand when this pattern of slow development evolves in [our genus] Homo,” says Alessia Nava, a bioarchaeologist at the Sapienza University of Rome who is not part of the study. “Now, we have an important hint.” Others caution that although the teeth of this youngster grew slowly, other individuals, including our direct ancestors, might have developed faster. Researchers have known since the 1930s that humans stay immature longer than other apes. Some posit our ancestors evolved slow growth to allow more time and energy to build bigger brains, or to learn how to adapt to complex social interactions and environments before they had children. To pin down when this slow pattern of growth arose, researchers often turn to teeth, especially permanent molars, because they persist in the fossil record and contain growth lines like tree rings. What’s more, the dental growth rate in humans and other primates correlates with the development of the brain and body.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 29562 - Posted: 11.16.2024

Ari Daniel The birds of today descended from the dinosaurs of yore. Researchers have known relatively little, however, about how the bird's brain took shape over tens of millions of years. "Birds are one of the most intelligent groups of living vertebrate animals," says Daniel Field, a vertebrate biologist at the University of Cambridge. "They really rival mammals in terms of their relative brain size and the complexity of their behaviors, social interactions, breeding displays." Now, a newly discovered fossil provides the most complete glimpse to date of the brains of the ancestral birds that once flew above the dinosaurs. The species was named Navaornis hestiae, and it's described in the journal Nature. Piecing together how bird brains evolved has been a challenge. First, most of the fossil evidence dates back to tens of millions of years before the end of the Cretaceous period when dinosaurs went extinct and birds diversified. In addition, the fossils of feathered dinosaurs that have turned up often have a key problem. "They're beautiful, but they're all like roadkill," says Luis Chiappe, a paleontologist and curator at the Natural History Museum of Los Angeles County. "They're all flattened and there are aspects that you're never going to be able to recover from those fossils." The shape and three-dimensional structure of the brain are among those missing aspects. But in 2016, Brazilian paleontologist William Nava discovered a remarkably well-preserved fossil in São Paulo state. It came from a prehistoric bird that fills in a crucial gap in understanding of how modern bird brains evolved. © 2024 npr

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: 29561 - Posted: 11.16.2024

By Kerri Smith Infographics by Nik Spencer There must be something about the human brain that’s different from the brains of other animals — something that enables humans to plan, imagine the future, solve crossword puzzles, tell sarcastic jokes and do the many other things that together make our species unique. And something that explains why humans get devastating conditions that other animals don’t — such as bipolar disorder and schizophrenia. Brain size is tightly correlated with body size in most animals. But humans break the mould. Our brains are much larger than expected given our body size. Here are some animals’ brains ranked according to size. Researchers often use a ratio called the encephalization quotient (EQ) to get an idea of how much larger or smaller an animal’s brain is compared with what would be expected given its body size. The EQ is 1.0 if the brain to body mass ratio meets expectations. Here are their brains scaled according to their EQ, with the actual brain sizes represented by dotted lines. The mouse brain is half as big as expected for its body size. The human brain is more than seven times the expected size. Although evolution has enlarged the human brain, it hasn’t done so uniformly: some brain areas have ballooned more than others. One particularly enlarged region is the cortex, an area that carries out planning, reasoning, language and many other behaviours that humans excel at. Other areas, such as the cerebellum — an area at the back of the brain that is densely populated with neurons, and which helps to conduct movement and planning — have expanded too. The prefrontal cortex has a similar structure in both chimps and humans, although it takes up much more real estate in the human brain than in the chimp brain.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 29539 - Posted: 11.02.2024

By Brandon Keim 1 How We Think About Animals Has a Long, Complicated History Back when I first started writing about scientific research on animal minds, I had internalized a straightforward historical narrative: The western intellectual tradition held animals to be unintelligent, but thanks to recent advances in the science, we were learning otherwise. The actual history is so much more complicated. The denial of animal intelligence does have deep roots, of course. You can trace a direct line from Aristotle, who considered animals capable of feeling only pain and hunger, to medieval Christian theologians fixated on their supposed lack of rationality, to Enlightenment intellectuals who likened the cries of beaten dogs to the squeaking of springs. But along the way, a great many thinkers, from early Greek philosopher Plutarch on through to Voltaire, pushed back. They saw animals as intelligent and therefore deserving of ethical regard, too. Those have always been the stakes of this debate: If animals are mindless then we owe them nothing. Through that lens it’s no surprise that societies founded on exploitation—of other human beings, of animals, of the whole natural world—would yield knowledge systems that formally regarded animals as dumb. The Plutarchs and Voltaires of the world were cast to the side. The scientific pendulum did swing briefly in the other direction, thanks in no small part to the popularity of Charles Darwin. He saw humans as related to other animals not only in body but in mind, and recognized rich forms of consciousness even in earthworms. But the backlash to that way of thinking was fierce, culminating in a principle articulated in the 1890s and later enshrined as Morgan’s Canon: An animal’s behavior should not be interpreted as evidence of a higher psychological faculty until all other explanations could be ruled out. Stupidity by default. © 2024 NautilusNext Inc.,

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Higher Cognition
Link ID: 29399 - Posted: 07.23.2024

By Dennis Normile For several decades, evidence has accumulated that animals turn to medicinal plants to relieve their ailments. Chimpanzees (and some other species) swallow leaves to mechanically clear the gut of parasites. Chimps also rely on the ingested pith of an African relative of the daisy, Vernonia amygdalina, to rid themselves of intestinal worms. Dolphins rub against antibacterial corals and sponges to treat skin infections. And recently, a male Sumatran orangutan was observed chewing the leaves of Fibraurea tinctoria, a South Asian plant with antibacterial and anti-inflammatory properties, and dabbing the juice onto a wound. These instances of animals playing doctor with therapeutic plants have typically been identified one by one. Today, in PLOS ONE, a multinational team proposes adding 17 samples from 13 plant species to the chimpanzee pharmacopia. “The paper provides important new findings about self-medication behavior in wild chimpanzees,” a topic that’s still relatively unknown, says Isabelle Laumer, a cognitive biologist at the Max Planck Institute of Animal Behavior and lead author on the orangutan self-medication paper who was not involved in the new chimp research. Observers with the team behind today's paper spent 4 months with each of two chimp communities habituated to human observers in Uganda’s Budongo Forest. The researchers supplemented their own observations with historical data. From the 170 chimps in the two communities, the observers zeroed in on 51 individuals suffering bacterial infections and inflammation as indicated by abnormal urine composition, diarrhea, traces of parasites, or apparent wounds. For 10 hours a day they followed the sick chimps through the forest, noting which plants they ate and when, and watching in particular to see whether the animals went out of their way to find and consume plants not part of their usual diet. In one example, researchers observed an individual suffering from diarrhea very briefly venture outside the group’s safe home territory to eat a small amount of dead wood from Alstonia boonei, a tree in the dogbane family. Chimps rarely eat dead wood, which is not nutritious for them, the team says.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 29364 - Posted: 06.24.2024

By Kermit Pattison Since the Stone Age, hunters have brought down big game with spears, atlatls, and bows and arrows. Now, a new study reveals traditional societies around the globe also relied on another deadly but often-overlooked weapon: our legs. According to a report published today in Nature Human Behaviour, running down big game such as antelope, moose, and even kangaroos was far more widespread than previously recognized. Researchers documented nearly 400 cases of endurance pursuits—a technique in which prey are chased to exhaustion—by Indigenous peoples around the globe between the 16th and 21st centuries. And in some cases, they suggest, it can be more efficient than stealthy stalking. The findings bolster the idea that humans evolved to be hunting harriers, says Daniel Lieberman, an evolutionary biologist at Harvard University. “Nobody else has come up with any other explanation for why humans evolved to run long distances,” says Lieberman, who adds that he’s impressed with the paper’s “depth of scholarship.” For decades, some anthropologists have argued that endurance running was among the first hunting techniques employed by early hominins in Africa. Advocates suggest subsequent millennia spent chasing down prey shaped many unique human features, including our springy arched feet, slow-twitch muscle fibers optimized for efficiency, heat-shedding bare skin, and prodigious ability to sweat. The “born to run” idea has become something of an origin story among many endurance athletes. But a pack of skeptics has dogged the theory. Critics cited the higher energetic costs of running over walking and noted that accounts of persistence hunting among modern foragers are rare. Yet hints of such pursuits kept popping up as Eugène Morin, an archaeologist at Trent University and co-author of the new paper, scoured the literature for a book he was writing on hunting among traditional societies. As he pored over early accounts by missionaries, travelers, and explorers, he repeatedly found descriptions of long-distance running and tracking. © 2024 American Association for the Advancement of Science.

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: 29309 - Posted: 05.16.2024

By Lucy Cooke When Frans de Waal was a psychology student at Nijmegen University (renamed in 2004 to Radboud University), in the Netherlands, he was tasked with looking after the department’s resident chimpanzees—Koos and Nozem. De Waal couldn’t help but notice how his charges became sexually aroused in the presence of his fellow female students. So, one day, de Waal decided to don a skirt, a pair of heels, and speak “in a high-pitched voice” to test their response. The chimps remained resolutely unstimulated by de Waal’s drag act, leading the young scientist to conclude there must be more to primate sexual discrimination than previously thought. De Waal died from stomach cancer on March 14 at his home in Georgia. He was 75. One of de Waal’s first forays into scientific experimentation demonstrates the playful curiosity and taboo-busting that underscored his extraordinary career as a primatologist. He was the recipient of numerous high-profile awards from the prestigious E.O. Wilson Literary Science Award to the Ig Nobel Prize—a satirical honor for research that makes people laugh and think. De Waal won the latter, with equal pride, for co-authoring a paper on chimpanzees’ tendency to recognize bums better than faces. It was this combination of humor, compassion, and iconoclastic thinking that drew me to his work. I first met him through his popular writing. The acclaimed primatologist was author of hundreds of peer-reviewed academic papers, but he was also that rare genius who could translate the complexities of his research into a highly digestible form, readily devoured by the masses. He was the author of 16 books, translated into over 20 languages. His public lectures were laced with deadpan humor, and a joy to attend. He saw no tension between being taken seriously as a pioneering scientist and hosting a Facebook page devoted to posting funny animal content. De Waal just loved watching animals. He was, by his own admission, a born naturalist. Growing up in a small town in southern Netherlands, he’d bred stickleback fish and raised jackdaw birds. So, it was only natural he’d wind up scrutinizing animal behavior for a career. What set de Waal’s observations apart was his ability to do so with fresh eyes. Where others could only see what they expected to see, de Waal managed to study primates outside of the accepted paradigms of the time. © 2024 NautilusNext Inc.,

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: 29208 - Posted: 03.23.2024

By Shaena Montanari When Nacho Sanguinetti-Scheck came across a seal study in Science in 2023, he saw it as confirmation of the “wild” research he had recently been doing himself. In the experiment, the researchers had attached portable, noninvasive electroencephalogram caps, custom calibrated to sense brain waves through blubber, to juvenile northern elephant seals. After testing the caps on five seals in an outdoor pool, the team attached the caps to eight seals free-swimming in the ocean. The results were striking: In the pool, the seals slept for six hours a day, but in the open ocean, they slept for just about two. And when seals were in REM sleep in the ocean, they flipped belly up and slowly spiraled downward, hundreds of meters below the surface. It was “one of my favorite papers of the past years,” says Sanguinetti-Scheck, a Harvard University neuroscience postdoctoral researcher who studies rodent behavior in the wild. “It’s just beautiful.” It was also the kind of experiment that needed to be done beyond the confines of a lab setting, he says. “You cannot see that in a pool.” Sanguinetti-Scheck is part of a growing cadre of researchers who champion the importance of studying animal behavior in the wild. Studying animals in the environment in which they evolved, these researchers say, can provide neuroscientific insight that is truly correlated with natural behavior. But not everyone agrees. In February, a group of about two dozen scientists and philosophers gathered in snowy, mountainous Terzolas, Italy, to wrestle with what, exactly, “natural behavior” means. “People don’t really think, ‘Well, what does it mean?’” says Mateusz Kostecki, a doctoral student at Nencki Institute of Experimental Biology in Poland. He helped organize the four-day workshop as “a good occasion to think critically about this trend.” © 2024 Simons Foundation

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: 29205 - Posted: 03.21.2024

By Alex Traub Frans de Waal, who used his study of the inner lives of animals to build a powerful case that apes think, feel, strategize, pass down culture and act on moral sentiments — and that humans are not quite as special as many of us like to think — died on Thursday at his home in Stone Mountain, Ga. He was 75. The cause was stomach cancer, his wife, Catherine Marin, said. A psychologist at Emory University in Atlanta and a research scientist at the school’s Yerkes National Primate Research Center, Professor de Waal objected to the common usage of the word “instinct.” He saw the behavior of all sentient creatures, from crows to persons, existing on the same broad continuum of evolutionary adaptation. “Uniquely human emotions don’t exist,” he argued in a 2019 New York Times guest essay. “Like organs, the emotions evolved over millions of years to serve essential functions.” The ambition and clarity of his thought, his skills as a storyteller and his prolific output made him an exceptionally popular figure for a primatologist — or a serious scientist of any kind. Two of his books, “Are We Smart Enough to Know How Smart Animals Are?” (2016) and “Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves” (2019), were best sellers. In the mid-1990s, when he was speaker of the House, Newt Gingrich put Professor de Waal’s first book, “Chimpanzee Politics” (1982), on a reading list for Republican House freshmen. The novelists Claire Messud and Sigrid Nunez both told The New York Times that they liked his writing. The actress Isabella Rossellini hosted a talk with him in Brooklyn last year. Major philosophers like Christine Korsgaard and Peter Singer wrote long, considered responses to his ideas. © 2024 The New York Times Company

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: 29200 - Posted: 03.21.2024