By Jake Currie One theory, the social brain hypothesis, says we owe our massive noggins in part to the evolutionary pressure exerted by the demands of large social groups. Because we needed to keep a running tally of friends and foes to navigate thorny hierarchies and shifting alliances, we had to have brains that were up to the task (which is why this theory is also known as the Machiavellian intelligence hypothesis). In many animals, especially mammals, there does seem to be a correlation between social group size and brain size. But there’s at least one big exception to this rule: cephalopods. Cephalopods like octopuses have huge brains but aren’t really known for their gregarious behavior. They tend to live solitary lives, mating without forming pair bonds and reproducing without parenting their young. In fact, their behavior can stray into the downright anti-social—many species are territorial, aggressive, and cannibalistic. Still, they’re incredibly intelligent. Octopuses use tools, solve problems, and even like to play. So if sociality can’t explain big cephalopod brains, what can? In a new paper published in iScience, an international team of researchers proposed a new version of the cultural brain hypothesis. This hypothesis—first advanced by one of the authors of the current study—states that big brains evolved to handle mountains of information that are learned both socially and asocially. In this latest research, the team focuses solely on the asocial pathway to brain evolution. To test their asocial brain hypothesis, the team compiled data on cephalopod brain size as well as ecological, behavioral, and social factors from 79 cephalopod species. They found that several ecological factors seemed to correlate with big cephalopod brains, especially the complexity of their habitats. Cephalopods that lived on the ocean floor and in shallow pools—where cleverness can be rewarded with calorie-rich prey—tended to have larger brains. Sociality, on the other hand, showed no such correlation.

Keyword: Evolution
Link ID: 30317 - Posted: 07.11.2026

By Jim Robbins Imagine a chicken that could speak or a pigeon with a voice rivaling that of the most musical songbirds. Granted, the world probably doesn’t need any gossiping chickens or pigeons breaking out in song. But why some birds learn to create a deep repertoire and others are unable to has long been a research focus of the neurobiologist Erich D. Jarvis. “Vocal learning, just like spoken language itself, is a rare trait,” said Dr. Jarvis, who directs the Neurogenetics of Language laboratory at Rockefeller University in New York. He studies the small group of species capable of speech, focusing on birds and mice, and he has long hoped to genetically engineer an animal that can vocalize in new ways. Introducing manipulated genes into the brain of a bird or a mouse that doesn’t vocalize could create that ability and provide new clues into the origins of speech. It may also one day help in finding treatments for people with speech problems or brain disorders. Dr. Jarvis, 60, didn’t start his career in neuroengineering. He once hoped to become a professional dancer, performing ballet at Manhattan’s renowned High School for the Performing Arts and then studying at the Alvin Ailey dance school. He was a member of the Westchester Ballet Company when he began wondering how the brain was able to create dance movements. His mentor at Rockefeller was Fernando Nottebohm, the researcher who discovered in the early 1980s that songbird brains generate new neurons each spring to enable them to sing. That revolutionary understanding of neurogenesis led to further findings that all brains, including human ones, grow new neurons throughout life. Until then, it had been scientific gospel that people came into the world with a fixed number. From 2002 to 2005, Dr. Jarvis helped lead the Avian Brain Nomenclature Consortium, a project that renamed the regions of the avian brain to show that it was remarkably sophisticated. The research undermined the use of the term “bird brain” as a pejorative. © 2026 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 30316 - Posted: 07.08.2026

By Sandy Ong On a Sunday afternoon in April, the main minibus terminal in Sukabumi, Indonesia, looked sleepy from the outside. But in an open space round the back, hundreds of men were gathered. Amid chatter and cigarette smoke, the air buzzed with excitement, for one of the region’s biggest bird-singing competitions was set to begin, and a motorbike was among the prizes. As the day progressed, dozens of songbirds were brought out for their 10-minute rounds, from tiny garden sunbirds and grey-cheeked bulbuls to larger oriental magpie-robins and orange-headed thrushes. Then the emcee announced the main event — the singing contest among the highly popular, strikingly handsome white-rumped shamas — and a hush fell over the crowd. The shamas’ owners murmured final words of encouragement and stepped away from their cages. Judges swept in with clipboards, assessing each bird for its song, ability to hold a steady tune, volume and showmanship. Soon it was down to a final two birds . . . and then “Baby White” was crowned the winner amid cheers from the crowd. Many men gathered on a patio beneath hanging cages holding songbirds Since the 1970s, songbird competitions have grown in popularity across Indonesia. With goats, motorcycles, watches and money (sometimes worth up to 10 years’ salary) up for grabs, the events are driving hordes of people to keep songbirds as pets. Indonesians have a long-standing culture of keeping birds as pets, and songbirds are especially popular, prized by collectors for their melodious singing and colorful plumage. “I keep songbirds as a hobby, to relieve stress and also gain a bit of money,” explained Harry Gunawan, a 78-year-old businessman and owner of 39 shamas, including the multiple prizewinning Baby White, while waiting for his new motorbike. Gunawan’s shamas are among an estimated 66 million to 84 million caged birds that are kept across Java, the island where 56 percent of Indonesia’s population lives and one in three households owns birds. These include more than 3 million white-rumped shamas and 2 million oriental magpie-robins. Wild birds are believed to be better songsters; hence, many are trapped in forests then crammed into tiny crates, drainpipes and even plastic bottles, destined for pet markets in Jakarta, Surabaya and other big cities. Birds that survive the journey — estimates of mortality rates range from 30 to 80 percent — will spend the rest of their lives confined to cages.

Keyword: Animal Communication; Language
Link ID: 30315 - Posted: 07.08.2026

By Natalia Mesa To accurately navigate the world, an animal must learn, remember and continually update how its body position relates to what it sees in the world around it. New findings reveal the circuit mechanisms responsible for this process in fruit flies—and upend a widely held assumption that this kind of learning relies on dopamine. The research “solves this long-standing problem of how you learn about landmarks in the world,” says Lisa Giocomo, professor of neurobiology at Stanford University, who was not involved in the study. “Over the last decade, some of the biggest insights into how the brain generates algorithms for navigational systems have come from Drosophila,” she says. “It’s been astonishing to see what’s been possible with that system.” When a neuron in a fly’s internal compass activates at the same time as a cell responding to a visual landmark, a third type of cell called an EL neuron releases the neuromodulator octopamine onto the visual inputs, according to the work, posted as a preprint in December 2025 and presented at the Jane Coffin Childs Symposium in May 2026. Octopamine acts as a signal that modifies the connection between the compass and visual cells, anchoring the fly’s sense of direction to visual cues. To their knowledge, the synaptic and circuit mechanisms the fly uses to update its internal compass work unlike any yet described, the study investigators say. “It’s a completely new learning mechanism, basically,” says Stanley Heinze, senior lecturer of sensory biology at Lund University, who was not involved in the study. Fruit flies, like other animals, have an internal compass made up of head direction cells that selectively activate based on the direction the fly faces. The fly’s internal representation of the world drifts without visual input but quickly reorients when familiar landmarks reappear. © 2026 Simons Foundation

Keyword: Learning & Memory; Evolution
Link ID: 30313 - Posted: 07.08.2026

By Libby Riddle A bear might seem like the scariest thing you could run into in a national park. But a new study suggests maybe you should be more worried about elk. Out of nearly 3,000 wildlife incidents in Canadian national parks, more than half involved an elk, researchers report July 2 in Frontiers in Conservation Science. But the risk of tangling with a given species also depended on what people were doing, say Holly Landles and conservation biologist Shashank Balakrishna of the University of York in England. Camping out? Be wary of elk grazing near your campsite. Quietly hiking or wildlife watching? Watch out for bears using the same trails. “By identifying situations where a potential conflict scenario is more likely, we can help visitors make informed decisions that improve safety whilst also reducing unnecessary disturbance to wildlife,” says Landles, who conducted this research as an undergraduate at York. Landles and Balakrishna analyzed 2,878 aggressive wildlife incidents from 2010 to 2023 involving five animals: black bears, grizzly bears, elk, coyotes and mule deer. Aggressive behaviors included chasing, attacking or bluffing a charge. The analysis identified which animal–human activity combinations were especially risky. Elk topped the list, involved in 62 percent of all the incidents. One of the riskiest combos was elk and camping — the animals turned up in 84 percent of campground incidents. This may be because Canada’s peak camping season aligns with when the animals mate and give birth — times of heightened aggression for the species. “Elk are herbivorous herd animals that don’t immediately inspire fear like a carnivore does,” Balakrishna says. Visitors may underestimate how aggressive they can be. © Society for Science & the Public 2000–2026.

Keyword: Aggression
Link ID: 30308 - Posted: 07.04.2026

By Nora Bradford Mirrors are tricky. Even humans aren’t born with an intuitive understanding of them; we have to learn how they work. Now, scientists have discovered that the California two-spot octopus (Octopus bimaculoides) can also learn to use mirrors, researchers report June 3 in Current Biology. When brainstorming octopus experiments, Mary Kieseler, a neuroscientist at the University of Fribourg in Switzerland, had wondered whether the famously smart creatures could pass the mirror test, which evaluates if an animal can identify itself in a mirror. Because of the challenging logistics the mirror self-recognition test would entail underwater, Kieseler and her team decided to first study whether octopuses could use mirrors as a tool to do something they’re already great at. And octopuses are great at hunting prey. The team began by habituating three wild-caught octopuses to a mirror covering half their tank. They let the octopuses hide from the mirror and even explore the other half of the tank behind it. After the octopuses became comfortable with seeing their reflection and eating in front of the mirror, the team gave them a task: Find a hidden jar with a tasty crab inside, placed where the snack could be found using only its reflection in the mirror. Initially, the octopuses approached the mirror, then turned around to find their prey. But after about 10 to 12 trials, each animal learned to crawl directly to the crab without the mirror pit stop. When using real crabs, there was no way to know whether the octopuses might have been relying on smell or another nonvisual sense to hunt, so Kieseler and her team came up with one final test. Rather than using real crabs, the team used virtual ones. © Society for Science & the Public 2000–2026

Keyword: Intelligence; Learning & Memory
Link ID: 30305 - Posted: 07.01.2026

By K. R. Callaway Strutting and fluttering around cities, pigeons have adapted to an ever-shifting environment. But their environment isn’t the only thing that’s constantly changing. New research suggests the birds themselves avoid stability in their decision-making, instead choosing to live “at the edge of chaos.” As model species for learning and behavior, these birds are helping researchers test a century-old law about how humans and other creatures learn. When learning something new, people and animals alike tend to repeat behaviors that are rewarded. First proposed by Edward Thorndike in 1898, this principle is so well established in psychology that it's become known as the law of effect. But the law implies that beyond making a behavior more frequent, rewards also make it more consistent: reducing variability in the specific way behaviors are performed over time. Although scientists have repeatedly tested whether rewards increase the frequency of behaviors, their effect on consistency is less well studied. University of Iowa experimental psychologist Edward A. Wasserman and his colleagues decided to put it to the test in pigeons—a species that has been integral to the study of learning at the university’s Comparative Cognition Laboratory for more than 50 years. And the study’s results, published in the Journal of Experimental Psychology: Animal Learning and Cognition, suggest these birds experience variability as the spice of life. To see how rewarded behaviors vary, the researchers gave pigeons a series of five colorful buttons to peck. They could peck any buttons in any order, but as long as they pecked five times, a treat would appear. Based on previous theories of learning, the scientists expected the pigeons might eventually slip into a routine—perhaps choosing to repeat patterns they know work or simply pecking the button nearest to them five times. Instead they continued pecking in a variety of patterns. © 2026 SCIENTIFIC AMERICAN,

Keyword: Learning & Memory; Evolution
Link ID: 30304 - Posted: 07.01.2026

Ian Sample Science editor A scientist who decoded the vocalisations that a bird uses to communicate has won a $100,000 prize for making progress towards a world in which humans can talk to the animals – without being met with a blank response. Dr Julie Elie at the University of California, Berkeley, was awarded the 2026 Coller-Dolittle prize for two-way interspecies communication after working out the 11 core calls in the zebra finch vocabulary and their meanings. Her work revealed how the birds announce who they are and what they are doing, and recognise one another regardless of what they are saying by using individual signatures. She also found that at times, the birds confused calls with similar meanings more than those that sounded the same. “I’m really super-honoured,” Elie said on winning the prize, adding that she hoped the work was a step forwards in the “great endeavour” to communicate with animals. Prof Yossi Yovel, a zoologist at Tel Aviv University and chair of the panel of judges, said the work marked “a key moment in the field”. The prize was launched in 2024 by the Jeremy Coller Foundation, which promotes awareness of animal welfare and animal sentience, in partnership with Tel Aviv University. Beyond the annual prizes for progress, the foundation has established a $10m grand prize for cracking the problem of two-way human-animal communication. Elie decided to study zebra finches because they are so vocal – meaning they produce plenty of data. “The question I asked myself when hearing these chatty songbirds was what are they saying?” she said. For more than a decade, Elie observed and recorded the sounds the birds made and classified the calls according to the situation and the bird that made them. She then used machine learning to analyse what and how information was encoded in the calls. Finally, she ran tests that showed the birds agreed with her classification. © 2026 Guardian News & Media Limited

Keyword: Animal Communication; Language
Link ID: 30301 - Posted: 06.27.2026

By Emily Anthes Humor is deeply personal. A punchline or a pratfall that leaves one person doubled over in delight might elicit blank stares from another. But laughter is universal, an innate instinct shared by humans everywhere. And not just humans. Chimps chuckle, gorillas guffaw, bonobos bust a gut. All the planet’s great apes laugh, and they often do so in the same kind of regular, repeating rhythm that humans do, scientists found in a small new study. The research sheds light on how laughter evolved with and among great apes, becoming faster and more variable in humans than in these other primate species. While nonhuman apes appeared to laugh in ways that were largely fixed, humans were more flexible in their expressions of mirth, changing up the tempo of their chuckles depending on the circumstance, the scientists found. “I think we can say we are the masters of laughter,” said Chiara De Gregorio, a research fellow at the University of Warwick in Britain and an author of the study. “We can have a small, polite laugh in front of the Queen of England, and then we are in the pub with our friends, and we laugh so much in a different way. We can even laugh in a way that communicates to the other person that we actually didn’t find the joke they said funny.” This wide-ranging repertoire requires significant vocal flexibility and control — the same skills that humans would have needed for spoken language. The study demonstrates the “uniqueness of human laughter,” said Greg Bryant, a cognitive scientist at the University of California, Los Angeles, who was not involved in the new research. “It provides a window into human vocal evolution.” In the new study, which was published on Thursday in the journal Communications Biology, the researchers analyzed the recorded laughter of four children and 13 young, captive apes: four orangutans, two gorillas, three bonobos and four chimpanzees. Some of the recordings featured laughter produced during play, while others captured laughter elicited by tickling. © 2026 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 30298 - Posted: 06.27.2026

Zoe Beketova When Adam Douglass began to study the tiny, transparent fish in the Danionella genus about 10 years ago, he had to get his animals from an out-of-state fish shop, where they were sold as an exotic pet breed. “The only information at all about trying to grow them in captivity came from online,” says Douglass, a neurobiologist at the University of Utah. Compared with zebrafish, which by that point had been a model species for biology research for decades, Danionella was little known to scientists. How things have changed. Last week, the Janelia Research Campus, the in-house research arm of the behemoth Howard Hughes Medical Institute (HHMI), announced a 10-year, roughly $1 billion research effort focused on using Danionella as a model for how brain cells and circuits drive complex behaviors in vertebrates. The effort will also draw on cutting-edge artificial intelligence (AI) tools to make sense of all the new data on the fish. “I think this is one of the most exciting opportunities that we’ve faced in the entire history of Janelia,” says neuroscientist Nelson Spruston, Janelia’s vice president and executive director. “There are a lot of structures in the brain and the rest of the body of fish that are identifiably similar to those of humans,” he adds, and there’s a long history of simple model organisms “leading to important insights that eventually result in cures and treatments for devastating diseases.” Danionella’s growing popularity comes from one (literally) clear advantage: Unlike zebrafish, which are transparent only for the first few weeks of their 3- to 4-year lives, Danionella remain so, meaning their brain is still visible—and easier to image—when they reach adulthood and engage in behaviors such as schooling, navigation, and courtship. The fish, only about the size of a grain of rice, never grow scales, develop pigmentation, or form a complete, bony skull. “All of these features that stand in the way of being able to get photons into and out of your skull [for imaging] are not there,” says Douglass, who has watched Danionella become a focus of dozens of labs worldwide

Keyword: Development of the Brain; Brain imaging
Link ID: 30294 - Posted: 06.24.2026

Nicola Davis Science correspondent From “Howdy” to “G’day”, English – like other languages – is rich in dialects. Now researchers have found sperm whales on different sides of the Mediterranean show similar variations in their vocalisations. Sperm whales communicate vocally using sequences of short clicks called codas. However, the rhythmic pattern of these clicks, known as the dialect, can differ between different matriarchal groups. Crucially, one group of sperm whales will only associate with another if they share the same dialect and hence belong to the same “vocal clan”. “The dialect is used to form social structures, within which these animals will cooperate,” said Dr Luke Rendell, of the University of St Andrews and a co-author of the new study, noting similarities in how humans might be more comfortable striking up a conversation with someone who sounds similar to themselves. a whale Now Rendell and colleagues say they have discovered two different dialects among Mediterraean sperm whales – a small, endangered population of a few thousand individuals that are thought to have first entered these waters about 20,000 years ago. What’s more, they say the finding offers new insights into how sperm whale dialects arise. Writing in the journal Proceedings of the Royal Society B, the team note genetic studies have previously suggested Mediterranean sperm whales have become isolated from other sperm whales. There are also signs that mating between those in the western and eastern Mediterranean basins is restricted, although individuals have been spotted moving between the two. © 2026 Guardian News & Media Limited

Keyword: Animal Communication; Language
Link ID: 30292 - Posted: 06.24.2026

By Jake Buehler A series of sharp cracks splits the nighttime air in a forest in the Andean foothills. But this isn’t the sound of boots snapping twigs underfoot. It’s a bird. Male scissor-tailed nightjars (Hydropsalis torquata) create these abrupt sounds by hitting the bones in their wings together in a forceful snap, researchers report in the May Journal of Avian Biology. Nightjars are largely nocturnal, insect-eating birds related to hummingbirds and swifts. H. torquata males are unusual for their exceptionally long, paired tail feathers. These males were already known to make explosive cracking noises at night as a mating signal to any nearby females. But little was understood about how they were doing it, says Juan Ignacio Areta, an evolutionary naturalist at Instituto de Bio y Geociencias del Noroeste Argentino in Salta, Argentina. “Many nocturnal animals are well known for being extremely silent, such as the ‘silent’ flight of owls,” Areta says. “We wanted to learn how it was possible for a nocturnal animal to make these loud sounds.” In late 2022, Areta and Christopher Clark — a behavioral ecologist at the University of California, Riverside — covertly filmed the male birds at night along a forest road near Salta. They used high-speed infrared cameras and then compared the footage to the sounds they were recording. Often, the nightjars would hop off the ground and swing their wings together behind their backs, creating a loud clack upon impact. Sometimes the males did this while flying or while mating with a female. The birds weren’t just hitting their feathers together. It was clear to the researchers that the snaps came from the wrist bones colliding just below the last bend in the wing. Areta and Clark think the bones vibrating from the forceful collision create the abrupt snapping sound. © Society for Science & the Public 2000–2026.

Keyword: Animal Communication; Sexual Behavior
Link ID: 30273 - Posted: 06.10.2026

By Claire L. Evans It was the dead of winter in Boston. The surface of the Charles River was frozen solid. But Zachary Kelso (opens a new tab) braved the biting cold to finally put to rest a mystery that has haunted neuroscience labs for over half a century. To do that, Kelso, a research assistant in the Harvard lab of the neuroscientist Sam Gershman (opens a new tab), needed some worms. Specifically, planarians: arrow-headed flatworms, which are among the simplest creatures to possess a brain and a nervous system with bilateral symmetry like ours. Normally, labs order these widely used model organisms from biological supply companies. But the mail-order worms weren’t up to snuff. So Gershman had dispatched Kelso to the Charles’ icy banks to catch some wild ones. “I thought, ‘I’m going to look crazy because I’m using a hammer to beat through the ice,’” Kelso recalled. “So I wore the more business end of business casual.” In philosophy, “qualia” refers to the subjective qualities of our experience: what it’s like for Alice to see blue or for Bob to feel delighted. Qualia are “the ways things seem to us,” as the late philosopher Daniel Dennett put it. In these essays, our columnists follow their curiosity, and explore important but not necessarily answerable scientific questions. It wouldn’t be the last time Kelso found himself in this situation. The Charles River planarians, it turned out, didn’t cut it either. Neither did the worms he sourced while stream-hopping around Eugene, Oregon, in March 2025. Nor did the ones he fished from Michigan lakes that June — this time in thigh-high waders — while picnicking families gawked from shore. Kelso diligently turned over rocks, angled with bits of meat tied to a string, and even followed maps from a vintage guidebook called The Fresh-Water Triclads of Michigan (opens a new tab). But his adventure was fruitless. Sure, he caught plenty of planarians. But back in Gershman’s lab, none of them would do what they were supposed to do. (C) Simons Foundation

Keyword: Learning & Memory; Evolution
Link ID: 30272 - Posted: 06.06.2026

By Erin Garcia de Jesús Buff-tailed bumblebees can figure out on their own how to use a ball as a ladder to nab sugar from an out-of-reach fake flower, researchers report in the June 4 Science. The insects worked out the trick without specific training for the solution, suggesting a remarkable capacity for solving problems. Bumblebees are brainy, with studies showing they may have emotions and can teach one another to score goals in a six-legged version of soccer. The new finding adds yet another skill to their repertoire. “Spontaneous problem-solving is something that has never been shown in any invertebrate before,” says Olli Loukola, a behavioral ecologist at the University of Oulu in Finland. Vertebrates including chimpanzees and parrots can problem solve on their own, although researchers typically focus on captive animals with plenty of experience working out puzzles. “Our study is the first one where we can be 100 percent sure that these individuals don’t have any prior experience about any problem-solving tasks,” Loukola says. Loukola and colleagues first taught bees two necessary associations: Balls are moveable objects and a blue ring — representing a flower — means food. The team then let the bees loose in plexiglass arenas too small for them to fly to reach a blue ring printed on the ceiling. © Society for Science & the Public 2000–2026.

Keyword: Learning & Memory; Intelligence
Link ID: 30271 - Posted: 06.06.2026

By Sara Novak Whether tucked away in a colony of coral, hidden in the darkness of an aquatic cave or floating catatonic just above the ocean floor, fish take opportunities for rest and recovery, just as we do. Like humans, most fish are diurnal, meaning they sleep mostly at night; while they don’t have eyelids, and therefore can’t shut out the darkness, light does disrupt their sleep. And just like us, when they snooze they’re motionless and slow to respond to environmental stimuli. If you deprive them of sleep, they will make up for the loss by sleeping longer the next night. Now, a new study, released this month in Nature Communications, shows just how much fish sleep really does resemble our own. By tracking eye movements of zebrafish, the researchers were able to identify four different substates of sleep, akin to the “stages” of sleep that scientists have described in humans. “There’s complexity to their sleep structure,” said Jennifer Mengbo Li, a co-author of the study and a neuroscientist at the Max Planck Institute for Biological Cybernetics in Germany. Three of the four substates happen at night, lasting a total of 10 hours. The first — and deepest — is characterized by a stone-cold stare. As the waking hours near, a second, lighter substate sets in: The zebrafish’s eyes twitch, sideways in the same direction, before moving slowly back to center. In the third substate, entered as morning approaches, both eyes turn to the same side and stay there. During the fourth and final substate, which takes place in brief bursts during the day, the zebrafish’s eyes move back and forth, as if sweeping the surroundings for potential risks. But the eyes can be deceiving: These five-to-10-minute naps are deep enough that much of the brain activity is suppressed, and the zebrafish are hard to wake up. © 2026 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 30263 - Posted: 05.30.2026

By Yasemin Saplakoglu When an optometrist shines a bright light into your eyes, a vast, branching tree sprouts in your field of vision. This is the shadow of blood vessels. Though we normally can’t perceive them, these vessels always occlude a portion of what we see, and for an important reason. They power the retina, a thin layer of nerve tissue in the back of the eye that communicates light signals to the brain. The retina is one of the body’s most energetically expensive tissues. Built from complex networks of sometimes more than 100 different types of neurons, retinal tissue consumes two to three times more energy than the same mass of typical brain tissue. That’s why most vertebrate retinas, including our own, are furrowed with dense, branching networks of blood vessels: to deliver oxygen and other ingredients for producing energy. But there’s a significant exception to this rule. Birds have retinas that mostly lack blood vessels. This may seem especially strange given birds’ exceptional vision. The bird retina is “one of the most metabolically active tissues in the animal kingdom, yet it worked with no apparent blood perfusion,” said Christian Damsgaard (opens a new tab), an evolutionary physiologist at Aarhus University. “It was a complete paradox.” For centuries this has puzzled scientists, who figured that the bird retina must obtain oxygen through a unique, undiscovered process. Damsgaard is the lead author of a study, published in the journal Nature (opens a new tab) in January 2026, that showed for the first time that bird retinas don’t have some unusual adaptation for acquiring oxygen — they survive without it entirely. Instead, to bring energy to the tissue, they use a process called anaerobic glycolysis that is significantly less efficient than oxygen-powered metabolism but gets the job done. © 2026.Simons Foundation

Keyword: Vision; Evolution
Link ID: 30247 - Posted: 05.16.2026

By Hannah Thomasy For nearly a decade, Vincent Bombail has been tickling rats. It’s been a standard technique used in the study of animal happiness. But not all rats particularly enjoy the experience, data show. Female rats prefer gentler, more playful tickling than males, Bombail and his colleagues report April 15 in Biology Letters. The findings suggest that the same physical experience evokes a different emotional response in different individuals, potentially influencing the results of studies on animal happiness. “This research helps us understand these animals as playful but also rich and complex and having opinions,” says Daniel Weary, an animal welfare scientist at the University of British Columbia who was not involved in the study. “Understanding the affective lives of animals is actually one of the coolest and most difficult questions there is in science,” he says. As early as the 1930s, researchers deliberately exposed rats to standardized negative experiences to study the physical effects of stress. Figuring out how to study positive experiences took longer. It wasn’t until the 1990s that researchers developed the standard tickling protocol, where a researcher flips a rat over, pins it on its back and tickles its belly. The protocol is intended to mimic the rough-and-tumble play of young male rats. © Society for Science & the Public 2000–2026.

Keyword: Emotions; Evolution
Link ID: 30242 - Posted: 05.16.2026

Liam Drew Three hearts; blue blood; no skeleton; arms like tongues. These are just some of the alien features of octopuses, squid and cuttlefish — members of the cephalopod family. The outlandish list continues. Cephalopod skin can taste chemicals, sense light and change colour and texture rapidly. In many species, the sucker-covered arms can even regenerate. These invertebrates have evolved independently from the vertebrate lineage for more than 600 million years. Their last common ancestor was probably a worm-like creature with a rudimentary nervous system and eye-like patches of light-sensitive cells. Despite this evolutionary gulf, vertebrates and these highly specialized molluscs share strange similarities. Their eyes, for example. “It’s eerie how similar they ended up,” says Cristopher Niell, a neuroscientist at the University of Oregon in Eugene. “The convergent evolution of the eye still blows my mind.” Now, one similarity is spurring a boom in cephalopod neuroscience. Around 400 million years ago, cuttlefish, squid and octopuses diverged from the only other living cephalopods — the nautiluses. They then lost their protective shells and evolved brains that are uniquely large among invertebrates. These brains bestow the soft-bodied cephalopods with high intelligence. Cuttlefish, squid and octopuses have excellent memories, use tools and are adept problem-solvers; they have a concept of time and are capable of delayed gratification. Cephalopods are the only non-vertebrate animals that have big, smart brains, says Cliff Ragsdale, a comparative neuroscientist at the University of Chicago in Illinois. And that presents a unique opportunity. Neuroscientists have gained a wealth of knowledge about how vertebrate brains work, but are increasingly looking to cephalopods for insights into ways to build large, high-functioning nervous systems. © 2026 Springer Nature Limited

Keyword: Evolution; Intelligence
Link ID: 30231 - Posted: 05.02.2026

Nicola Davis Science correspondent It has long been known that dogs have less between their ears than wolves, but now research has suggested their brains started to get smaller at least 5,000 years ago. Experts say the results offer fresh insights into the domestication of our canine companions. However, the findings are unlikely to explain why your spaniel will only drink from a muddy puddle: the researchers say a reduction in brain size does not mean dogs are dafter than their wolf-like ancestors. “The way our dogs live nowadays doesn’t give them the opportunity to always express most of their intelligence,” said Dr Thomas Cucchi, first author of the study from the French National Centre for Scientific Research. “But they are extremely clever and domestication didn’t make them stupid, but made them really capable of reading us and communicating with us.” The relationship between humans and canines is ancient, with research revealing the oldest direct genetic evidence for domestic dogs dates back more than 15,000 years. But while a reduction in brain size is typically considered a hallmark of domestication, there has long been debate over exactly when dogs ended up with smaller brains than wolves, with some experts suggesting this may have occurred early in the dog-human relationship. However, others argue smaller brain size is not a hallmark of domestication but instead reflects the emergence of pedigree breeds in the last 200 years. Writing in the journal Royal Society Open Science, Cucchi and colleagues studied CT scans of the skulls of 22 prehistoric wolves and dogs, dating from 35,000 to 5,000 years ago, as well as CT scans from the skulls of 59 modern wolves and 104 modern dogs. The latter included different modern breeds as well as stray or “village” dogs, and dingoes. © 2026 Guardian News & Media Limited

Keyword: Evolution
Link ID: 30220 - Posted: 04.29.2026

By Jake Currie Chimpanzees and humans share 98 percent of their genomes, so what’s in that 2 percent that makes us uniquely human? According to a new study published in Science Advances, a tiny portion of these genes play an outsized role in our language skills—and Neanderthals had the same sequences. Subscribe to skip ads Featured Video These segments of the human genome, known as Human Ancestor Quickly Evolved Regions (HAQERs) are non-coding sequences that showed accelerated evolution after humans split from the ancestor they shared with apes. Even though they represent only 0.1 percent of our genes, they’re responsible for the neural “hardware” for language. “What we’re seeing is how a very small part of the genome can have an outsized influence, not just on who we were as a species, but on who we are as individuals,” study author Jacob Michaelson of the University of Iowa said in a statement. “These aren’t genes we’re talking about. They’re regulatory regions that act like the volume knob on genes.” The HAQERs also interact with another vital speech gene: FOXP2. Identified in 1998, FOXP2 is a transcription factor active in the development of the neural circuitry of language use, and mutations in the gene can cause speech problems. “So, if the HAQERs are like volume knobs that can be turned, FOXP2 is one of the hands that is turning these volume knobs,” Michaelson said. © Nautilus 2026

Keyword: Language; Evolution
Link ID: 30215 - Posted: 04.26.2026