By Phie Jacobs Is there really such a thing as a “male” or “female” brain? Sex certainly seems to affect a person’s risk of developing various psychiatric and other brain-related conditions—but scientists aren’t entirely sure why. Attention-deficit/hyperactivity disorder for example, is more commonly diagnosed in individuals who were assigned male at birth (AMAB), whereas those assigned female at birth (AFAB) are more likely to exhibit symptoms of anxiety. It’s unclear, however, whether these differences are actually driven by sex, or have more to do with how people are perceived and treated based on their sex or gender. Now, new research suggests sex and gender are associated with distinct brain networks. Published today in Science Advances, the findings draw on brain imaging data from nearly 5000 children to reveal that gender and sex aren’t just distinct from one another in society—they also play unique roles in biology. In science, the term “biological sex” encompasses a variety of genetic, hormonal, and anatomical characteristics. People are typically assigned “male” or “female” as their sex at birth, although the medical establishment in recent years has begun to acknowledge that sex doesn’t always fall neatly into binary categories. Indeed, about 0.05% of children born in the United States are assigned intersex at birth. Gender, by contrast, has more to do with a person’s attitudes, feelings, and behavior—and may not always align with the sex they were assigned at birth. These nuances often go unrecognized in neuroscience, says Sheila Shanmugan, a reproductive psychiatrist at the University of Pennsylvania who wasn’t involved in the new study. Sex and gender-based differences in the brain “have historically been understudied,” she explains, “and terms describing each are often conflated.” © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Brain imaging
Link ID: 29393 - Posted: 07.13.2024

By Claire Yuan Men and women experience pain differently, and until now, scientists didn’t know why. New research says it may be in part due to differences in male and female nerve cells. Pain-sensing nerve cells from male and female animal tissues responded differently to the same sensitizing substances, researchers report June 3 in Brain. The results suggest that at the cellular level, pain is produced differently between the sexes. The results might allow researchers “to come up with drugs that would be specific to treat female patients or male patients,” says Katherine Martucci, a neuroscientist who studies chronic pain at Duke University School of Medicine and was not involved in the study. “There’s no debate about it. They’re seeing these differences in the cells.” Some types of chronic and acute pain appear more often in one sex, but it’s unclear why. For instance, about 50 million adults in the United States suffer from chronic pain conditions, many of which are more common in women (SN: 5/22/23). Similar disparities exist for acute conditions. Such differences prompted pain researcher Frank Porreca of the University of Arizona Health Sciences in Tucson and colleagues to study nerve cells called nociceptors, which can act like alarm sensors for the body. The cells’ pain sensors, found in skin, organs and elsewhere in the body, can detect potentially dangerous stimuli and send signals to the brain, which then interprets the information as pain. In some cases, the nerve cells can become more sensitive to outside stimulation, registering even gentle sensations — like a shirt rubbing sunburned skin — as pain. © Society for Science & the Public 2000–2024.

Keyword: Pain & Touch; Sexual Behavior
Link ID: 29366 - Posted: 06.24.2024

By Sara Reardon Specific nerve cells on the penis and clitoris detect vibrations and then become activated, causing sexual behaviours such as erections, a study in mice has revealed1. The findings could lead to new treatments for conditions such as erectile dysfunction, or for restoring sexual function in people with lower-body paralysis. Krause corpuscles — nerve endings in tightly wrapped balls located just under the skin — were first discovered in human genitals more than 150 years ago. The structures are similar to touch-activated corpuscles found on people’s fingers and hands, which respond to vibrations as the skin moves across a textured surface. But there is little research into how the genital corpuscles work and how they are involved in sex, probably because the topic is sometimes considered taboo. “It’s been hard to get people to work on this because some people have a hard time talking about it,” says David Ginty, a sensory neurobiologist at Harvard Medical School in Boston, Massachusetts, who led the team that conducted the latest research. “But I don’t, because the biology is so interesting.” Ginty and other sensory biologists have long wanted to study these mysterious neuron balls. But activating and tracking specific neurons was nearly impossible until advanced molecular techniques emerged in the past 20 years. In a 19 June paper in Nature1, Ginty and his collaborators activated the Krause corpuscles in both male and female mice using various mechanical and electrical stimuli. The neurons fired in response to low-frequency vibrations in the range of 40–80 hertz. Ginty notes that these frequencies are generally used in many sex toys; humans, it seems, realized that this was the best way to stimulate Krause corpuscles before any official experiments were published. © 2024 Springer Nature Limited

Keyword: Sexual Behavior; Pain & Touch
Link ID: 29365 - Posted: 06.24.2024

By Virginia Morell Leaping over waves or body surfing side by side, dolphins are a fun-loving bunch. But their frolicking—and that of species from hyenas to humans—has long baffled evolutionary biologists. Why expend so much energy on play? A new study offers an intriguing explanation: Juvenile male dolphins use play to acquire the skills required for fathering calves, researchers report today in the Proceedings of the National Academy of Sciences. Most significantly, the scientists found the most playful males go on to have more calves as adults. The study is likely to spur further research into play behavior in additional species, other scientists say. “It’s exciting research, and it solves an evolutionary puzzle,” says Jennifer Smith, a behavioral ecologist at the University of Wisconsin–Eau Claire. “This is the first study to link play behavior in the wild to reproductive success.” Since 1982, scientists have observed some 200 male Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the exceptionally clear waters of Shark Bay in Australia. About 20 years ago, the researchers noticed that young males, 4 to 12 years old, often played together as if they were herding a fertile female, flanking her on either side, while swimming in sync with each other and making popping vocalizations. This kind of “synchronicity is crucial for male reproduction,” says Kathryn Holmes, a behavioral biologist with the Shark Bay Dolphin Research project and lead author of the new study. The young dolphins’ behaviors were strikingly similar to those of the adults. “We wondered if this was ‘play practice’ for the adult behaviors,” Holmes says. So she and her colleagues closely tracked 28 juvenile males for 4 to 5 months over several years, recording their interactions and play behaviors. When socializing, the males “played almost continuously,” Holmes says. “They seemed to never tire of their games.” © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 29353 - Posted: 06.11.2024

By Amorina Kingdon Like most humans, I assumed that sound didn’t work well in water. After all, Jacques Cousteau himself called the ocean the “silent world.” I thought, beyond whales, aquatic animals must not use sound much. How wonderfully wrong I was. In water a sound wave travels four and a half times faster, and loses less energy, than in air. It moves farther and faster and carries information better. In the ocean, water exists in layers and swirling masses of slightly different densities, depending on depth, temperature, and saltiness. The physics-astute reader will know that the density of the medium in which sound travels influences its speed. So, as sound waves spread through the sea, their speed changes, causing complex reflection or refraction and bending of the sound waves into “ducts” and “channels.” Under the right circumstances, these ducts and channels can carry sound waves hundreds and even thousands of kilometers. What about other sensory phenomena? Touch and taste work about the same in water as in air. But the chemicals that tend to carry scent move slower in water than in air. And water absorbs light very easily, greatly diminishing visibility. Even away from murky coastal waters, in the clearest seas, light vanishes below several hundred meters and visibility below several dozen. So sound is often the best, if not only, way for ocean and freshwater creatures to signal friends, detect enemies, and monitor the world underwater. And there is much to monitor: Earthquakes, mudslides, and volcanic activity rumble through the oceans, beyond a human’s hearing range. Ice cracks, booms, and scrapes the seafloor. Waves hiss and roar. Raindrops plink. If you listen carefully, you can tell wind speed, rainfall, even drop size, by listening to the ocean as a storm passes. Even snowfall makes a sound. © 2024 NautilusNext Inc.,

Keyword: Animal Communication; Sexual Behavior
Link ID: 29341 - Posted: 06.04.2024

By Sumeet Kulkarni As spring turns to summer in the United States, warming conditions have started to summon enormous numbers of red-eyed periodical cicadas out of their holes in the soil across the east of the country. This year sees an exceptionally rare joint emergence of two cicada broods: one that surfaces every 13 years and another with a 17-year cycle. They last emerged together in 1803, when Thomas Jefferson was US president. This year, billions or even trillions of cicadas from these two broods — each including multiple species of the genus Magicicada — are expected to swarm forests, fields and urban neighbourhoods. To answer readers’ cicada questions, Nature sought help from three researchers. Katie Dana is an entomologist affiliated with the Illinois Natural History Survey at the University of Illinois at Urbana-Champaign. John Lill is an insect ecologist at George Washington University in Washington DC. Fatima Husain is a cognitive neuroscientist at the University of Illinois at Urbana-Champaign. Their answers have been edited for length and clarity. Why do periodical cicadas have red eyes? JL: We’re not really sure. We do know that cicadas’ eyes turn red in the winter before the insects come out. The whole coloration pattern in periodical cicadas is very bright: red eyes, black and orange wings. They’re quite different from the annual cicadas, which are green and black, and more camouflaged. It’s a bit of an enigma why the periodical ones are so brightly coloured, given that it just makes them more obvious to predators. There are no associated defences with being brightly coloured — it kind of flies in the face of what we know about bright coloration in a lot of other animals, where usually it’s some kind of signal for toxicity. There also exist mutants with brown, orange, golden or even blue eyes. People hunt for blue-eyed ones; it’s like trying to find a four-leaf clover. © 2024 Springer Nature Limited

Keyword: Animal Communication; Sexual Behavior
Link ID: 29339 - Posted: 06.04.2024

Sacha Pfeiffer A few weeks ago, at about 6:45 in the morning, I was at home, waiting to talk live on the air with Morning Edition host Michel Martin about a story I'd done, when I suddenly heard a loud metallic hammering. It sounded like a machine was vibrating my house. It happened again about 15 seconds later. And again after that. This rhythmic clatter seemed to be coming from my basement utility closet. Was my furnace breaking? Or my water heater? I worried that it might happen while I was on the air. Luckily, the noise stopped while I spoke with Michel, but restarted later. This time I heard another sound, a warbling or trilling, possibly inside my chimney. Was there an animal in there? I ran outside, looked up at my roof — and saw a woodpecker drilling away at my metal chimney cap. I've seen and heard plenty of woodpeckers hammer on trees. But never on metal. So to find out why the bird was doing this, I called an expert: Kevin McGowan, an ornithologist at the Cornell Lab of Ornithology who recently created a course called "The Wonderful World of Woodpeckers." McGowan said woodpeckers batter wood to find food, make a home, mark territory and attract a mate. But when they bash away at metal, "what the birds are trying to do is make as big a noise as possible," he said, "and a number of these guys have found that — you know what? If you hammer on metal, it's really loud!" Woodpeckers primarily do this during the springtime breeding season, and their metallic racket has two purposes, "basically summarized as: All other guys stay away, all the girls come to me," McGowan said. "And the bigger the noise, the better." © 2024 npr

Keyword: Sexual Behavior; Animal Communication
Link ID: 29333 - Posted: 06.02.2024

By Clay Risen Academic conferences are usually staid affairs, but the 1973 International Symposium on Gender Identity, held in Dubrovnik, Yugoslavia, was an exception. Everything was peaceful until a psychologist named John Money stood and yelled, “Mickey Diamond, I hate your guts!” Milton Diamond, a sexologist who had gone by Mickey since childhood, was sitting on the other side of the room. Dr. Money and Dr. Diamond were bitter rivals: Dr. Money, a nationally recognized researcher at Johns Hopkins University, had long argued that sexual and gender identity are neutral at birth and shaped primarily by an infant’s surroundings. Dr. Diamond, who was just beginning his career at the University of Hawaii, strongly disagreed, and had said so repeatedly — including in a widely read 1965 critique of Dr. Money’s work. He took particular issue with Dr. Money’s recommendation that intersex infants have surgery to “correct” their genitals. Dr. Money rushed over to Dr. Diamond, getting in his face, furiously insisting he was right. Dr. Diamond only replied, “The data is not there.” At one point, eyewitnesses reported that Dr. Money slugged Dr. Diamond, though Dr. Diamond later said he didn’t remember it. The incident, reported by the journalist John Colapinto in Rolling Stone magazine and in a subsequent book, “As Nature Made Him: The Boy Who Was Raised as a Girl” (2000), was especially heated because of a recent announcement by Dr. Money. He had been working with a child who in 1965, after his penis was irreparably damaged during a circumcision, had undergone further surgery to remove his male genitalia. The child was then raised as a girl, taking on all the conventional physical and emotional characteristics of a female adolescent — happily, Dr. Money said. Though the child was not born intersex, Dr. Money claimed that the case proved that gender and sexual identity were malleable and that intersex children should indeed receive surgery. © 2024 The New York Times Company

Keyword: Sexual Behavior
Link ID: 29297 - Posted: 05.09.2024

By Gillian Dohrn “Puppy-dog eyes didn’t just evolve for us, in domestic dogs,” says comparative anatomist Heather Smith. Her team’s work has thrown a 2019 finding1 that the muscles in dogs’ eyebrows evolved to communicate with humans in the doghouse by showing that African wild dogs also have the muscles to make the infamous pleading expression. The study was published on 10 April in The Anatomical Record2. Now, one of the researchers who described the evolution of puppy-dog eyebrow muscles is considering what the African dog discovery means for canine evolution. “It opens a door to thinking about where dogs come from, and what they are,” says Anne Burrows, a biological anthropologist at the Duquesne University in Pittsburgh, Pennsylvania, and author of the earlier paper. The 2019 study garnered headlines around the world when it found that the two muscles responsible for creating the sad–sweet puppy-dog stare are pronounced in several domestic breeds (Canis familiaris), but almost absent in wolves (Canis lupus). If the social dynamic between humans and dogs drove eyebrow evolution, Smith wondered whether the highly social African wild dog might also have expressive brows. African wild dogs (Lycaon pictus) are native to sub-Saharan Africa. Between 1997 and 2012, their numbers dropped by half in some areas. With only 8,000 or so remaining in the wild, studying them is difficult but crucial for conservation efforts. Smith, who is based at Midwestern University in Glendale, Arizona, and her colleagues dissected a recently deceased African wild dog from Phoenix Zoo. They found that both the levator anguli oculi medalis (LAOM) and the retractor anguli oculi lateralis (RAOL) muscles, credited with creating the puppy-dog expression, were similar in size to those of domestic dog breeds.

Keyword: Emotions; Sexual Behavior
Link ID: 29295 - Posted: 05.07.2024

By Elizabeth Anne Brown The beluga whale wears its heart on its sleeve — or rather, its forehead. Researchers have created a visual encyclopedia of the different expressions that belugas (Delphinapterus leucas) in captivity seem to make with their highly mobile “melon,” a squishy deposit of fat on the forehead that helps direct sound waves for echolocation. Using muscles and connective tissue, belugas can extend the melon forward until it juts over their lips like the bill of a cap; mush it down until it’s flattened against their skull; lift it vertically to create an impressive fleshy top hat; and shake it with such force that it jiggles like Jell-O. “If that doesn’t scream ‘pay attention to me,’ I don’t know what does,” says animal behaviorist Justin Richard of the University of Rhode Island in Kingston. “It’s like watching a peacock spread their feathers.” Before Richard became a scientist, he spent a decade as a beluga trainer at the Mystic Aquarium in Connecticut, working closely with the enigmatic animals. “Even as a trainer, I knew the shapes meant something,” Richard says. “But nobody had been able to put together enough observations to make sense of it.” Over the course of a year, from 2014 to 2015, Richard and colleagues recorded interactions between four belugas at the Mystic Aquarium. Analyzing the footage revealed that the belugas make five distinct melon shapes the scientists dubbed flat, lift, press, push and shake. The belugas sported an average of nearly two shapes per minute during social interaction, the team reports March 2 in Animal Cognition. © Society for Science & the Public 2000–2024

Keyword: Animal Communication; Evolution
Link ID: 29291 - Posted: 05.03.2024

By Michael S. Rosenwald Prairie voles are stocky rodents and Olympian tunnellers that surface in grassy areas to feast on grass, roots and seeds with their chisel-shaped teeth, sprouting migraines in farmers and gardeners. But to Larry Young, they were the secret to understanding romance and love. Professor Young, a neuroscientist at Emory University in Atlanta, used prairie voles in a series of experiments that revealed the chemical process for the pirouette of heart-fluttering emotions that poets have tried to put into words for centuries. He died on March 21 in Tsukuba, Japan, where he was helping to organize a scientific conference. He was 56. The cause was a heart attack, his wife, Anne Murphy, said. With their beady eyes, thick tails and sharp claws, prairie voles are not exactly cuddly. But among rodents, they are uniquely domestic: They are monogamous, and the males and females form a family unit to raise their offspring together. “Prairie voles, if you take away their partner, they show behavior similar to depression,” Professor Young told The Atlanta-Journal Constitution in 2009. “It’s almost as if there’s withdrawal from their partner.” That made them ideal for laboratory studies examining the chemistry of love. In a study published in 1999, Professor Young and his colleagues exploited the gene in prairie voles associated with the signaling of vasopressin, a hormone that modulates social behavior. They boosted vasopressin signaling in mice, which are highly promiscuous. Headline writers were amused. “Gene Swap Turns Lecherous Mice Into Devoted Mates,” The Ottawa Citizen declared. The Fort Worth Star-Telegram: “Genetic Science Makes Mice More Romantic.” The Independent in London: “‘Perfect Husband’ Gene Discovered.” © 2024 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29288 - Posted: 05.03.2024

By Joshua Cohen In the U.S., 23 states have passed legislation to ban medicalized care for minors with gender dysphoria, or the experience of distress that can occur when a person’s gender identity does not match the sex they were assigned at birth. On the other hand, 12 state legislatures have introduced laws to protect access to youth transgender care. Such care can include puberty blockers, which are medications that suppress the body’s production of sex hormones, and cross-sex hormones like testosterone or estrogen that alter secondary sex characteristics. It also may include sexual reassignment surgery in rare instances. U.S. policies on both ends of the spectrum are not science-driven but rather emanate from polar-opposite ideologies. Unlike in Europe, there doesn’t appear to be room for a non-ideological process for determining what the best care is that weighs the emerging clinical evidence and adjusts policies accordingly. As reported in Axios, state efforts to restrict various forms of transgender medicine are being fueled by religious groups that aim to shape policy based on their strongly held beliefs around the immutability of gender and family. Faith-based objections to transgender care come from a worldview in which God created humans as male or female. Here, the role of parents’ rights features prominently, as well as a conviction that adolescents are insufficiently mature to decide on trans alterations to their bodies. Moreover, lawmakers point out that some young people later regret having had irreversible body-altering treatment. The bans on care can be driven by extreme religious views. In one example, The Associated Press reported last year that Oklahoma state Sen. David Bullard introduced what he called the “Millstone Act” — a bill that would make the act of providing gender transition procedures to anyone under the age of 26 a felony — by citing a Bible passage that suggests those who cause children to sin should be drowned. The age limit was later lowered to 18.

Keyword: Sexual Behavior
Link ID: 29287 - Posted: 05.03.2024

In 2023, students protested against a new policy in Texas, where parents would be notified if their child asks to be identified as transgender.Credit: Brett Coomer/Houston Chronicle/Getty This week, Nature is launching a collection of opinion articles on sex and gender in research. Further articles will be published in the coming months. The series will highlight the necessity and challenges of studying a topic that is both hugely under-researched and, increasingly, the focus of arguments worldwide — many of which are neither healthy nor constructive. Some scientists have been warned off studying sex differences by colleagues. Others, who are already working on sex or gender-related topics, are hesitant to publish their views. Such a climate of fear and reticence serves no one. To find a way forward we need more knowledge, not less. Nearly 20 researchers from diverse fields, including neuroscience, psychology, immunology and cancer, have contributed to the series, which provides a snapshot of where scholars studying sex and gender are aligned — and where they are not. In time, we hope this collection will help to shape research, and provide a reference point for moderating often-intemperate debates. In practice, people use sex and gender to mean different things. But researchers studying animals typically use sex to refer to male and female individuals, as defined by various anatomical and other biological features. In studies involving humans, participants are generally asked to identify their own sex and/or gender category. Here, gender usually encompasses social and environmental factors, including gender roles, expectations and identity. © 2024 Springer Nature Limited

Keyword: Sexual Behavior
Link ID: 29281 - Posted: 05.02.2024

By Tim Vernimmen Most amphibians aren’t exactly doting parents — they just find a partner and release as many eggs or sperm as possible, in hopes that viable larvae will hatch from at least some fertilized eggs, and at least some of those larvae will survive to adulthood. Yet in as many as one in five amphibian species, one or both parents stick around to care for their offspring, using a staggering variety of strategies. The most well-known amphibian parents are the brightly colored poison frogs, a group of around 200 species that will repeatedly be leaping into view in this article. Yet their parenting skills may not be as exceptional as once thought, says biologist Jennifer Stynoski of the University of Costa Rica, who decided to study this group when she spotted them on a field trip as a student years ago. “I think they’ve just received a lot of attention because they’re so beautiful. They’re very cute to study.” So — what makes an exemplary amphibian parent? Much remains to be discovered, but some common principles have emerged. Stay away from the water Unlike reptiles and the birds that evolved from them, the ancestors of today’s amphibians never developed eggs with tough, watertight shells. This means their eggs need water to survive, as do the gilled larvae that usually come wriggling out. Yet the ponds in which many amphibians deposit their eggs are full of other animals, many eager to supplement their diet by slurping up a mouthful of eggs. “This must be one reason why so many species have evolved ways to lay their eggs away from the water,” says behavioral ecologist Eva Ringler of the University of Bern in Switzerland. © 2024 Annual Reviews

Keyword: Sexual Behavior; Evolution
Link ID: 29279 - Posted: 04.30.2024

By Angie Voyles Askham Larry Young, a neuroscientist known for illuminating oxytocin’s outsized role in social bonding, died of a heart attack last month at the age of 57. In his 30-year career at Emory University, Young teased apart the neurobiology of love and relationships—from the receptors that make voles monogamous to the hormones that shape sociability in psychiatric disorders. He founded and directed both the Center for Translational Social Neuroscience and the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory, and he helped establish the Laboratory of Social Neural Networks in Tsukuba, Japan. “His impact has been enormous,” says Steven Phelps, professor of integrative biology at the University of Texas at Austin, who was Young’s first postdoctoral researcher at Emory. “He brought molecular biology to what we would call non-model organisms, the species that are normally neglected by mainstream science.” Young also fostered collaborations through the many international conferences he organized, and he raised the public profile of neuroscience research through his dedication to science communication. He served as a hub within the field of social neuroscience—someone who connected others across continents and research modalities—says Steve Chang, associate professor of psychology and neuroscience at Yale University. “Everyone feels there is now a giant hole.” Young grew up on a farm in Sylvester, Georgia, a small town that claims the title of “Peanut Capital of the World.” As a child, he loved animals and kept many pets—including, for a time, a possum that he carried around on his head, Young recalled on a podcast in 2022. He had thoughts of becoming a veterinarian but pivoted to medicine when, in his biochemistry classes at the University of Georgia, he became fascinated with genetics and how nature manages to translate a string of letters to the behaviors necessary for survival. © 2024 Simons Foundation

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29257 - Posted: 04.16.2024

Jon Hamilton A sibling can change your life — even before you're born. That's because when males and females share a womb, sex hormones from one fetus can cause lasting changes in the others. It's called the intrauterine position phenomenon, or intrauterine position effects, and different versions of it have been observed in rodents, pigs, sheep — and, probably, humans. "It's really kind of strange to think something so random as who you develop next to in utero can absolutely change the trajectory of your development," says Bryce Ryan, a professor of biology at the University of Redlands. The phenomenon is more than a scientific oddity. It helped establish that even tiny amounts of hormone-like chemicals, like those found in some plastics, could affect a fetus. Cattle breeders in ancient Rome may have been the first people to recognize the importance of a sibling's sex. They realized that when a cow gives birth to male-female twins, the female is usually sterile. These females, known as freemartins, also act more like males when they grow up. Scientists began to understand why in the early 1900s. They found evidence that hormones from the male twin were affecting the female's development. The effect is less obvious in other mammals, Ryan says. Female offspring in rodents, for example, can still reproduce, but they have measurable differences in sexual development and tend to be more aggressive. © 2024 npr

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29250 - Posted: 04.11.2024

By Gina Jiménez Being pregnant and giving birth changes a person’s brain, but the brain looks different depending on whether it’s examined during pregnancy or after a person gives birth, a recent study found. The research is helping disentangle some of the mysteries in the long-ignored field of maternal neuroscience. The study, published in January in Nature Neuroscience, followed more than 100 new mothers from near the end of their pregnancy until about three weeks on average after they had their baby. Previous research had examined birthing parents’ brain before they gave birth or during the postpartum period, but this study observed them both before and after birth, and it also took into account whether they had a vaginal birth or C-section. The findings reveal temporary changes in some brain regions and more permanent ones in a brain circuit that activates when people are not engaged in an active task and that is also involved in self-reflection and empathizing with others. The study has “ordered” some of the scientific disagreements in the field, says its senior author Susana Carmona, a neuroscience researcher now at Gregorio Marañón General University Hospital in Spain.* “It fills important gaps—that is why it’s novel,” says Joe Lonstein, a neuroscientist who studies animal parenting behaviors at Michigan State University but was not involved with the new paper. “There were things we just didn’t know about the timing of events.” Much of the scientific literature on pregnancy and postpartum neuroscience is only around a decade old. A 2016 study found that gray matter decreased in women after they had a baby for the first time, and the reductions persisted for at least six years after pregnancy. In contrast, other studies have observed that gray matter increases in the first weeks after people give birth. The new paper helps reconcile these results: the researchers found that women indeed lost gray matter during pregnancy and childbirth but got it back in most brain areas after they had their baby. © 2024 SCIENTIFIC AMERICAN,

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29197 - Posted: 03.19.2024

By Jake Buehler In the middle of the night in a humid coastal rainforest, a litter of pink, hairless babies snuggle with their mother. They stir and squeak for milk, their mother obliges, and they are sated. But these are no puppies or cubs. They are snake-shaped amphibians, far closer to frogs than foxes. These ringed caecilian moms feed their hatchlings a kind of “milk” brewed in the reproductive tract, researchers report in the March 8 Science. The long, cylindrical creatures are the first egg-laying amphibians known to feed hatchlings this way. The discovery suggests the evolution of parental care across animal life is more diverse than researchers thought. For an animal with so few discernable external features, caecilians are a fount of strange biology. Caecilians are elusive, legless, burrowing amphibians that are nearly blind (SN: 6/19/17). Some species, like the ringed caecilian (Siphonops annulatus) in the new study, have poisonous slime, may be venomous and feed their own skin to their young (SN: 7/3/20). Herpetologist Carlos Jared of the Instituto Butantan in São Paulo and his colleagues have been studying these eccentric animals for years. In previous studies, the team noticed that ringed caecilian hatchlings, which live their first two months out of the egg in their mother’s care, spent much of their time around the end of her body near the shared opening of the reproductive, digestive and urinary systems — an anatomical part called the vent. The female would periodically expel a thick fluid from the vent, which the young would enthusiastically feed on. “Some [young] even stuck their heads inside this opening,” Jared says. In the new work, the team collected 16 females and their newly hatched litters from Bahia state in Brazil, bringing them into the lab for observation. There, the researchers recorded the amphibians’ interactions, accumulating over 240 hours of video footage. The team recorded 36 feedings, which often involved the babies wriggling and nibbling at their mother’s vent while making high-pitched noises. Mom would then raise that end of her body and release the fluid. This happened up to six times per day and appeared to be in response to the babies’ pleas. © Society for Science & the Public 2000–2024.

Keyword: Sexual Behavior
Link ID: 29188 - Posted: 03.09.2024

By Emily Anthes Colombia is a bird watcher’s paradise. Its stunningly diverse ecosystems — which include mountain ranges, mangrove swamps, Caribbean beaches and Amazonian rainforests — are home to more avian species than any other country on Earth. So when Hamish Spencer, an evolutionary biologist at the University of Otago in New Zealand, booked a bird-watching vacation in Colombia, he was hoping to spot some interesting and unusual creatures. He got more than he bargained for. During one outing, in early January 2023, the proprietor of a local farm drew his attention to a green honeycreeper, a small songbird that is common in forests ranging from southern Mexico to Brazil. But this particular green honeycreeper had highly unusual plumage. The left side of its body was covered in shimmering spring-green feathers, the classic coloring for females. Its right side, however, was iridescent blue, the telltale marker of a male. The bird appeared to be a bilateral gynandromorph: female on one side and male on the other. “It was just incredible,” Dr. Spencer said. “We were lucky to see it.” Gynandromorphism has been documented in a variety of birds, as well as insects, crustaceans and other organisms. But it’s a relatively rare and poorly understood phenomenon. The bird Dr. Spencer saw in Colombia is only the second known case of bilateral gynandromorphism in a green honeycreeper — and the first documented in the wild. © 2024 The New York Times Compan

Keyword: Sexual Behavior
Link ID: 29180 - Posted: 03.07.2024

Philip Hoare Whales are extraordinarily sensuous creatures. Those blubbery bodies are highly sensitive, and sensitised. At social meetings, pods of sperm, humpback and right whales will roll around one another’s bodies for hours at a time. I’ve seen a group of right whales engaged in foreplay and penetration lasting an entire morning. I have also watched a male-female couple so blissfully conjoined that they appeared unbothered by our little fishing boat as they passed underneath it. And in what may sound like a career of cetacean voyeurism, I have also been caught up in a fast-moving superpod of dusky dolphins continually penetrating each other at speed, regardless of the gender of their partner. That’s why this week’s report of the first scientifically documented male-to-male sexual interactions between two humpback whales off the coast of Hawaii is not surprising. The remarkable image of a two-metre whale penis entering another male “leaves little room for discussion that there is a sexual component to such behaviour”, as one whale scientist, Jeroen Hoekendijk at the Wageningen Marine Research institute in the Netherlands, notes drily. In fact, one of the whales was ailing and there has been speculation that the encounter may not have been consensual or that the healthy whale was actually giving comfort to the other. Whatever the truth, such “flagrant” acts also expose many of our human presumptions about sexuality, gender and identity. Off the north-west Pacific coast of the US, male orcas often leave family pods to rub their erections against each other’s bellies. But females have also reportedly been seen engaging in sexual contact with one another, too. © 2024 Guardian News & Media Limited

Keyword: Sexual Behavior
Link ID: 29173 - Posted: 03.02.2024