Biology

the-nine-armed-octopus-and-the-oddities-of-the-cephalopod-nervous-system

The nine-armed octopus and the oddities of the cephalopod nervous system

Biology, brains, neurobiology, octopus, Science / /

A mix of autonomous and top-down control manage the octopus’s limbs.

With their quick-change camouflage and high level of intelligence, it’s not surprising that the public and scientific experts alike are fascinated by octopuses. Their abilities to recognize faces, solve puzzles, and learn behaviors from other octopuses make these animals a captivating study.

To perform these processes and others, like crawling or exploring, octopuses rely on their complex nervous system, one that has become a focus for neuroscientists. With about 500 million neurons—around the same number as dogs—octopuses’ nervous systems are the most complex of any invertebrate. But, unlike vertebrate organisms, the octopus’s nervous system is also decentralized, with around 350 million neurons, or 66 percent of it, located in its eight arms.

“This means each arm is capable of independently processing sensory input, initiating movement, and even executing complex behaviors—without direct instructions from the brain,” explains Galit Pelled, a professor of Mechanical Engineering, Radiology, and Neuroscience at Michigan State University who studies octopus neuroscience. “In essence, the arms have their own ‘mini-brains.’”

A decentralized nervous system is one factor that helps octopuses adapt to changes, such as injury or predation, as seen in the case of an Octopus vulgaris, or common octopus, that was observed with nine arms by researchers at the ECOBAR lab at the Institute of Marine Research in Spain between 2021 and 2022.

By studying outliers like this cephalopod, researchers can gain insight into how the animal’s detailed scaffolding of nerves changes and regrows over time, uncovering more about how octopuses have evolved over millennia in our oceans.

Brains, brains, and more brains

Because each arm of an octopus contains its own bundle of neurons, the limbs can operate semi-independently from the central brain, enabling faster responses since signals don’t always need to travel back and forth between the brain and the arms. In fact, Pelled and her team recently discovered that “neural signals recorded in the octopus arm can predict movement type within 100 milliseconds of stimulation, without central brain involvement.” She notes that “that level of localized autonomy is unprecedented in vertebrate systems.”

Though each limb moves on its own, the movements of the octopus’s body are smooth and conducted with a coordinated elegance that allows the animal to exhibit some of the broadest range of behaviors, adapting on the fly to changes in its surroundings.

“That means the octopus can react quickly to its environment, especially when exploring, hunting, or defending itself,” Pelled says. “For example, one arm can grab food while another is feeling around a rock, without needing permission from the brain. This setup also makes the octopus more resilient. If one arm is injured, the others still work just fine. And because so much decision-making happens at the arms, the central brain is freed up to focus on the bigger picture—like navigating or learning new tasks.”

As if each limb weren’t already buzzing with neural activity, things get even more intricate when researchers zoom in further—to the nerves within each individual sucker, a ring of muscular tissue, which octopuses use to sense and taste their surroundings.

“There is a sucker ganglion, or nerve center, located in the stalk of every sucker. For some species of octopuses, that’s over a thousand ganglia,” says Cassady Olson, a graduate student at the University of Chicago who works with Cliff Ragsdale, a leading expert in octopus neuroscience.

Given that each sucker has its own nerve centers—connected by a long axial nerve cord running down the limb—and each arm has hundreds of suckers, things get complicated very quickly, as researchers have historically struggled to study this peripheral nervous system, as it’s called, within the octopus’s body.

“The large size of the brain makes it both really exciting to study and really challenging,” says Z. Yan Wang, an assistant professor of biology and psychology at the University of Washington. “Many of the tools available for neuroscience have to be adjusted or customized specifically for octopuses and other cephalopods because of their unique body plans.”

While each limb acts independently, signals are transmitted back to the octopus’s central nervous system. The octopus’ brain sits between its eyes at the front of its mantle, or head, couched between its two optic lobes, large bean-shaped neural organs that help octopuses see the world around them. These optic lobes are just two of the over 30 lobes experts study within the animal’s centralized brain, as each lobe helps the octopus process its environment.

This elaborate neural architecture is critical given the octopus’s dual role in the ecosystem as both predator and prey. Without natural defenses like a hard shell, octopuses have evolved a highly adaptable nervous system that allows them to rapidly process information and adjust as needed, helping their chances of survival.

Some similarities remain

While the octopus’s decentralized nervous system makes it a unique evolutionary example, it does have some structures similar to or analogous to the human nervous system.

“The octopus has a central brain mass located between its eyes, and an axial nerve cord running down each arm (similar to a spinal cord),” says Wang. “The octopus has many sensory systems that we are familiar with, such as vision, touch (somatosensation), chemosensation, and gravity sensing.”

Neuroscientists have homed in on these similarities to understand how these structures may have evolved across the different branches in the tree of life. As the most recent common ancestor for humans and octopuses lived around 750 million years ago, experts believe that many similarities, from similar camera-like eyes to maps of neural activities, evolved separately in a process known as convergent evolution.

While these similarities shed light on evolution’s independent paths, they also offer valuable insights for fields like soft robotics and regenerative medicine.

Occasionally, unique individuals—like an octopus with an unexpected number of limbs—can provide even deeper clues into how this remarkable nervous system functions and adapts.

Nine arms, no problem

In 2021, researchers from the Institute of Marine Research in Spain used an underwater camera to follow a male Octopus vulgaris, or common octopus. On its left side, three arms were intact, while the others were reduced to uneven, stumpy lengths, sharply bitten off at varying points. Although the researchers didn’t witness the injury itself, they observed that the front right arm—known as R1—was regenerating unusually, splitting into two separate limbs and giving the octopus a total of nine arms.

“In this individual, we believe this condition was a result of abnormal regeneration [a genetic mutation] after an encounter with a predator,” explains Sam Soule, one of the researchers and the first author on the corresponding paper recently published in Animals.

The researchers named the octopus Salvador due to its bifurcated arm coiling up on itself like the two upturned ends of Salvador Dali’s moustache. For two years, the team studied the cephalopod’s behavior and found that it used its bifurcated arm less when doing “riskier” movements such as exploring or grabbing food, which would force the animal to stretch its arm out and expose it to further injury.

“One of the conclusions of our research is that the octopus likely retains a long-term memory of the original injury, as it tends to use the bifurcated arms for less risky tasks compared to the others,” elaborates Jorge Hernández Urcera, a lead author of the study. “This idea of lasting memory brought to mind Dalí’s famous painting The Persistence of Memory, which ultimately became the title of the paper we published on monitoring this particular octopus.”

While the octopus acted more protective of its extra limb, its nervous system had adapted to using the extra appendage, as the octopus was observed, after some time recovering from its injuries, using its ninth arm for probing its environment.

“That nine-armed octopus is a perfect example of just how adaptable these animals are,” Pelled adds. “Most animals would struggle with an unusual body part, but not the octopus. In this case, the octopus had a bifurcated (split) arm and still used it effectively, just like any other arm. That tells us the nervous system didn’t treat it as a mistake—it figured out how to make it work.”

Kenna Hughes-Castleberry is the science communicator at JILA (a joint physics research institute between the National Institute of Standards and Technology and the University of Colorado Boulder) and a freelance science journalist. Her main writing focuses are quantum physics, quantum technology, deep technology, social media, and the diversity of people in these fields, particularly women and people from minority ethnic and racial groups. Follow her on LinkedIn or visit her website.

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Research roundup: 7 stories we almost missed

acoustics, Archaeology, architecture, Biology, Physics, primates, robotics, Science / /

Ping-pong bots, drumming chimps, picking styles of two jazz greats, and an ancient underground city’s soundscape

Time lapse photos show a new ping-pong-playing robot performing a top spin. Credit: David Nguyen, Kendrick Cancio and Sangbae Kim

It’s a regrettable reality that there is never time to cover all the interesting scientific stories we come across each month. In the past, we’ve featured year-end roundups of cool science stories we (almost) missed. This year, we’re experimenting with a monthly collection. May’s list includes a nifty experiment to make a predicted effect of special relativity visible; a ping-pong playing robot that can return hits with 88 percent accuracy; and the discovery of the rare genetic mutation that makes orange cats orange, among other highlights.

Special relativity made visible

The Terrell-Penrose-Effect: Fast objects appear rotated

Credit: TU Wien

Perhaps the most well-known feature of Albert Einstein’s special theory of relativity is time dilation and length contraction. In 1959, two physicists predicted another feature of relativistic motion: an object moving near the speed of light should also appear to be rotated. It’s not been possible to demonstrate this experimentally, however—until now. Physicists at the Vienna University of Technology figured out how to reproduce this rotational effect in the lab using laser pulses and precision cameras, according to a paper published in the journal Communications Physics.

They found their inspiration in art, specifically an earlier collaboration with an artist named Enar de Dios Rodriguez, who collaborated with VUT and the University of Vienna on a project involving ultra-fast photography and slow light. For this latest research, they used objects shaped like a cube and a sphere and moved them around the lab while zapping them with ultrashort laser pulses, recording the flashes with a high-speed camera.

Getting the timing just right effectively yields similar results to a light speed of 2 m/s. After photographing the objects many times using this method, the team then combined the still images into a single image. The results: the cube looked twisted and the sphere’s North Pole was in a different location—a demonstration of the rotational effect predicted back in 1959.

DOI: Communications Physics, 2025. 10.1038/s42005-025-02003-6  (About DOIs).

Drumming chimpanzees

A chimpanzee feeling the rhythm. Credit: Current Biology/Eleuteri et al., 2025.

Chimpanzees are known to “drum” on the roots of trees as a means of communication, often combining that action with what are known as “pant-hoot” vocalizations (see above video). Scientists have found that the chimps’ drumming exhibits key elements of musical rhythm much like humans, according to  a paper published in the journal Current Biology—specifically non-random timing and isochrony. And chimps from different geographical regions have different drumming rhythms.

Back in 2022, the same team observed that individual chimps had unique styles of “buttress drumming,” which served as a kind of communication, letting others in the same group know their identity, location, and activity. This time around they wanted to know if this was also true of chimps living in different groups and whether their drumming was rhythmic in nature. So they collected video footage of the drumming behavior among 11 chimpanzee communities across six populations in East Africa (Uganda) and West Africa (Ivory Coast), amounting to 371 drumming bouts.

Their analysis of the drum patterns confirmed their hypothesis. The western chimps drummed in regularly spaced hits, used faster tempos, and started drumming earlier during their pant-hoot vocalizations. Eastern chimps would alternate between shorter and longer spaced hits. Since this kind of rhythmic percussion is one of the earliest evolved forms of human musical expression and is ubiquitous across cultures, findings such as this could shed light on how our love of rhythm evolved.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.04.019  (About DOIs).

Distinctive styles of two jazz greats

Wes Montgomery (left)) and Joe Pass (right) playing guitars

Jazz lovers likely need no introduction to Joe Pass and Wes Montgomery, 20th century guitarists who influenced generations of jazz musicians with their innovative techniques. Montgomery, for instance, didn’t use a pick, preferring to pluck the strings with his thumb—a method he developed because he practiced at night after working all day as a machinist and didn’t want to wake his children or neighbors. Pass developed his own range of picking techniques, including fingerpicking, hybrid picking, and “flat picking.”

Chirag Gokani and Preston Wilson, both with Applied Research Laboratories and the University of Texas, Austin, greatly admired both Pass and Montgomery and decided to explore the underlying the acoustics of their distinctive playing, modeling the interactions of the thumb, fingers, and pick with a guitar string. They described their research during a meeting of the Acoustical Society of America in New Orleans, LA.

Among their findings: Montgomery achieved his warm tone by playing closer to the bridge and mostly plucking at the string. Pass’s rich tone arose from a combination of using a pick and playing closer to the guitar neck. There were also differences in how much a thumb, finger, and pick slip off the string:  use of the thumb (Montgomery) produced more of a “pluck” compared to the pick (Pass), which produced more of a “strike.” Gokani and Wilson think their model could be used to synthesize digital guitars with a more realistic sound, as well as helping guitarists better emulate Pass and Montgomery.

Sounds of an ancient underground city

A collection of images from the underground tunnels of Derinkuyu.

Credit: Sezin Nas

Turkey is home to the underground city Derinkuyu, originally carved out inside soft volcanic rock around the 8th century BCE. It was later expanded to include four main ventilation channels (and some 50,000 smaller shafts) serving seven levels, which could be closed off from the inside with a large rolling stone. The city could hold up to 20,000 people and it  was connected to another underground city, Kaymakli, via tunnels. Derinkuyu helped protect Arab Muslims during the Arab-Byzantine wars, served as a refuge from the Ottomans in the 14th century, and as a haven for Armenians escaping persecution in the early 20th century, among other functions.

The tunnels were rediscovered in the 1960s and about half of the city has been open to visitors since 2016. The site is naturally of great archaeological interest, but there has been little to no research on the acoustics of the site, particularly the ventilation channels—one of Derinkuyu’s most unique features, according to Sezin Nas, an architectural acoustician at Istanbul Galata University in Turkey.  She gave a talk at a meeting of the Acoustical Society of America in New Orleans, LA, about her work on the site’s acoustic environment.

Nas analyzed a church, a living area, and a kitchen, measuring sound sources and reverberation patterns, among other factors, to create a 3D virtual soundscape. The hope is that a better understanding of this aspect of Derinkuyu could improve the design of future underground urban spaces—as well as one day using her virtual soundscape to enable visitors to experience the sounds of the city themselves.

MIT’s latest ping-pong robot

Robots playing ping-pong have been a thing since the 1980s, of particular interest to scientists because it requires the robot to combine the slow, precise ability to grasp and pick up objects with dynamic, adaptable locomotion. Such robots need high-speed machine vision, fast motors and actuators, precise control, and the ability to make accurate predictions in real time, not to mention being able to develop a game strategy. More recent designs use AI techniques to allow the robots to “learn” from prior data to improve their performance.

MIT researchers have built their own version of a ping-pong playing robot, incorporating a lightweight design and the ability to precisely return shots. They built on prior work developing the Humanoid, a small bipedal two-armed robot—specifically, modifying the Humanoid’s arm by adding an extra degree of freedom to the wrist so the robot could control a ping-pong paddle. They tested their robot by mounting it on a ping-pong table and lobbing 150 balls at it from the other side of the table, capturing the action with high-speed cameras.

The new bot can execute three different swing types (loop, drive, and chip) and during the trial runs it returned the ball with impressive accuracy across all three types: 88.4 percent, 89.2 percent, and 87.5 percent, respectively. Subsequent tweaks to theirrystem brought the robot’s strike speed up to 19 meters per second (about 42 MPH), close to the 12 to 25 meters per second of advanced human players. The addition of control algorithms gave the robot the ability to aim. The robot still has limited mobility and reach because it has to be fixed to the ping-pong table but the MIT researchers plan to rig it to a gantry or wheeled platform in the future to address that shortcoming.

Why orange cats are orange

an orange tabby kitten

Cat lovers know orange cats are special for more than their unique coloring, but that’s the quality that has intrigued scientists for almost a century. Sure, lots of animals have orange, ginger, or yellow hues, like tigers, orangutans, and golden retrievers. But in domestic cats that color is specifically linked to sex. Almost all orange cats are male. Scientists have now identified the genetic mutation responsible and it appears to be unique to cats, according to a paper published in the journal Current Biology.

Prior work had narrowed down the region on the X chromosome most likely to contain the relevant mutation. The scientists knew that females usually have just one copy of the mutation and in that case have tortoiseshell (partially orange) coloring, although in rare cases, a female cat will be orange if both X chromosomes have the mutation. Over the last five to ten years, there has been an explosion in genome resources (including complete sequenced genomes) for cats which greatly aided the team’s research, along with taking additional DNA samples from cats at spay and neuter clinics.

From an initial pool of 51 candidate variants, the scientists narrowed it down to three genes, only one of which was likely to play any role in gene regulation: Arhgap36. It wasn’t known to play any role in pigment cells in humans, mice, or non-orange cats. But orange cats are special; their mutation (sex-linked orange) turns on Arhgap36 expression in pigment cells (and only pigment cells), thereby interfering with the molecular pathway that controls coat color in other orange-shaded mammals. The scientists suggest that this is an example of how genes can acquire new functions, thereby enabling species to better adapt and evolve.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.03.075  (About DOIs).

Not a Roman “massacre” after all

Two of the skeletons excavated by Mortimer Wheeler in the 1930s, dating from the 1st century AD.

Credit: Martin Smith

In 1936, archaeologists excavating the Iron Age hill fort Maiden Castle in the UK unearthed dozens of human skeletons, all showing signs of lethal injuries to the head and upper body—likely inflicted with weaponry. At the time, this was interpreted as evidence of a pitched battle between the Britons of the local Durotriges tribe and invading Romans. The Romans slaughtered the native inhabitants, thereby bringing a sudden violent end to the Iron Age. At least that’s the popular narrative that has prevailed ever since in countless popular articles, books, and documentaries.

But a paper published in the Oxford Journal of Archaeology calls that narrative into question. Archaeologists at Bournemouth University have re-analyzed those burials, incorporating radiocarbon dating into their efforts. They concluded that those individuals didn’t die in a single brutal battle. Rather, it was Britons killing other Britons over multiple generations between the first century BCE and the first century CE—most likely in periodic localized outbursts of violence in the lead-up to the Roman conquest of Britain. It’s possible there are still many human remains waiting to be discovered at the site, which could shed further light on what happened at Maiden Castle.

DOI: Oxford Journal of Archaeology, 2025. 10.1111/ojoa.12324  (About DOIs).

Photo of Jennifer Ouellette

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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Scientists figure out how the brain forms emotional connections

Biology, emitions, neurobiology, Science / /

Whenever something bad happens to us, brain systems responsible for mediating emotions kick in to prevent it from happening again. When we get stung by a wasp, the association between pain and wasps is encoded in the region of the brain called the amygdala, which connects simple stimuli with basic emotions.

But the brain does more than simple associations; it also encodes lots of other stimuli that are less directly connected with the harmful event—things like the place where we got stung or the wasps’ nest in a nearby tree. These are combined into complex emotional models of potentially threatening circumstances.

Till now, we didn’t know exactly how these models are built. But we’re beginning to understand how it’s done.

Emotional complexity

“Decades of work has revealed how simple forms of emotional learning occurs—how sensory stimuli are paired with aversive events,” says Joshua Johansen, a team director at the Neural Circuitry of Learning and Memory at RIKEN Center for Brain Science in Tokyo. But Johansen says that these decades didn’t bring much progress in treating psychiatric conditions like anxiety and trauma-related disorders. “We thought if we could get a handle of more complex emotional processes and understand their mechanisms, we may be able to provide relief for patients with conditions like that,” Johansen claims.

To make it happen, his team performed experiments designed to trigger complex emotional processes in rats while closely monitoring their brains.

Johansen and Xiaowei Gu, his co-author and colleague at RIKEN, started by dividing the rats into two groups. The first “paired” group of rats was conditioned to associate an image with a sound. The second “unpaired” group watched the same image and listened to the same sound, but not at the same time. This prevented the rats from making an association.

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Carnivorous crocodile-like monsters used to terrorize the Caribbean

Biology, crocodiles, evolution, migration, predators, Science / /

How did reptilian things that looked something like crocodiles get to the Caribbean islands from South America millions of years ago? They probably walked.

The existence of any prehistoric apex predators in the islands of the Caribbean used to be doubted. While their absence would have probably made it even more of a paradise for prey animals, fossils unearthed in Cuba, Puerto Rico, and the Dominican Republic have revealed that these islands were crawling with monster crocodyliform species called sebecids, ancient relatives of crocodiles.

While sebecids first emerged during the Cretaceous, this is the first evidence of them lurking outside South America during the Cenozoic epoch, which began 66 million years ago. An international team of researchers has found that these creatures would stalk and hunt in the Caribbean islands millions of years after similar predators went extinct on the South American mainland. Lower sea levels back then could have exposed enough land to walk across.

“Adaptations to a terrestrial lifestyle documented for sebecids and the chronology of West Indian fossils strongly suggest that they reached the islands in the Eocene-Oligocene through transient land connections with South America or island hopping,” researchers said in a study recently published in Proceedings of the Royal Society B.

Origin story

During the late Eocene to early Oligocene periods of the mid-Cenozoic, about 34 million years ago, many terrestrial carnivores already roamed South America. Along with crocodyliform sebecids, these included enormous snakes, terror birds, and metatherians, which were monster marsupials. At this time, the sea levels were low, and the islands of the Eastern Caribbean are thought to have been connected to South America via a land bridge called GAARlandia (Greater Antilles and Aves Ridge). This is not the first land bridge to potentially provide a migration opportunity.

Fragments of a single tooth unearthed in Seven Rivers, Jamaica, in 1999 are the oldest fossil evidence of a ziphodont crocodyliform (a group that includes sebecids) in the Caribbean. It was dated to about 47 million years ago, when Jamaica was connected to an extension of the North American continent known as the Nicaragua Rise. While the tooth from Seven Rivers is thought to have belonged to a ziphodont other than a sebacid, that and other vertebrate fossils found in Jamaica suggest parallels with ecosystems excavated from sites in the American South.

The fossils found in areas like the US South that the ocean would otherwise separate suggest more than just related life forms. It’s possible that the Nicaragua Rise provided a pathway for migration similar to the one sebecids probably used when they arrived in the Caribbean islands.

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Cyborg cicadas play Pachelbel’s Canon

biobots, Biology, cicadas, cyborg cicadas, entomology, insects, Science / /

The distinctive chirps of singing cicadas are a highlight of summer in regions where they proliferate; those chirps even featured prominently on Lorde’s 2021 album Solar Power. Now, Japanese scientists at the University of Tsukuba have figured out how to transform cicadas into cyborg insects capable of “playing” Pachelbel’s Canon. They described their work in a preprint published on the physics arXiv. You can listen to the sounds here.

Scientists have been intrigued by the potential of cyborg insects since the 1990s, when researchers began implanting tiny electrodes into cockroach antennae and shocking them to direct their movements. The idea was to use them as hybrid robots for search-and-rescue applications.

For instance, in 2015, Texas A&M scientists found that implanting electrodes into a cockroach’s ganglion (the neuron cluster that controls its front legs) was remarkably effective at successfully steering the roaches 60 percent of the time. They outfitted the roaches with tiny backpacks synced with a remote controller and administered shocks to disrupt the insect’s balance, forcing it to move in the desired direction

And in 2021, scientists at Nanyang Technological University in Singapore turned Madagascar hissing cockroaches into cyborgs, implanting electrodes in sensory organs known as cerci that were then connected to tiny computers. Applying electrical current enabled them to steer the cockroaches successfully 94 percent of the time in simulated disaster scenes in the lab.

The authors of this latest paper were inspired by that 2021 project and decided to apply the basic concept to singing cicadas, with the idea that cyborg cicadas might one day be used to transmit warning messages during emergencies. It’s usually the males who do the singing, and each species has a unique song. In most species, the production of sound occurs via a pair of membrane structures called tymbals, which are just below each side of the insect’s anterior abdominal region. The tymbal muscles contract and cause the plates to vibrate while the abdomen acts as a kind of resonating chamber to amplify the song.

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Some flies go insomniac to ward off parasites

Biology, circadian rhythm, Drosophila, evolution, fruit flies, parasites, Science / /

Those genes associated with metabolism were upregulated, meaning they showed an increase in activity. An observed loss of body fat and protein reserves was evidently a trade-off for resistance to mites. This suggests there was increased lipolysis, or the breakdown of fats, and proteolysis, the breakdown of proteins, in resistant lines of flies.

Parasite paranoia

The depletion of nutrients could make fruit flies less likely to survive even without mites feeding off them, but their tenaciousness when it comes to staying up through the night suggests that being parasitized by mites is still the greater risk. Because mite-resistant flies did not sleep, their oxygen consumption and activity also increased during the night to levels no different from those of control group flies during the day.

Keeping mites away involves moving around so the fly can buzz off if mites crawl too close. Knowing this, Benoit wanted to see what would happen if the resistant flies’ movement was restricted. It was doom. When the flies were restrained, the mite-resistant flies were as susceptible to mites as the controls. Activity alone was important for resisting mites.

Since mites are ectoparasites, or external parasites (as opposed to internal parasites like tapeworms), potential hosts like flies can benefit from hypervigilance. Sleep is typically beneficial to a host invaded by an internal parasite because it increases the immune response. Unfortunately for the flies, sleeping would only make them an easy meal for mites. Keeping both stereoscopic eyes out for an external parasite means there is no time left for sleep.

“The pattern of reduced sleep likely allows the flies to be more responsive during encounters with mites during the night,” the researchers said in their study, which was recently published in Biological Timing and Sleep. “There could be differences in sleep occurring during the day, but these differences may be less important as D. melanogaster sleeps much less during the day.”

Fruit flies aren’t the only creatures with sleep patterns that parasites disrupt. Evidence of shifts in sleep and rest in birds and bats has been shown to happen when there is a risk of parasitism after dark. For the flies, exhaustion has the upside of better fertility if they manage to avoid bites, so a mate must be worth all those sleepless nights.

Biological Timing and Sleep, 2025.  DOI: 10.1038/s44323-025-00031-7

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DNA links modern pueblo dwellers to Chaco Canyon people

ancient DNA, Archeology, Biology, Genetics, Genomics, human biology, Science / /

A thousand years ago, the people living in Chaco Canyon were building massive structures of intricate masonry and trading with locations as far away as Mexico. Within a century, however, the area would be largely abandoned, with little indication that the same culture was re-established elsewhere. If the people of Chaco Canyon migrated to new homes, it’s unclear where they ended up.

Around the same time that construction expanded in Chaco Canyon, far smaller pueblos began appearing in the northern Rio Grande Valley hundreds of kilometers away. These have remained occupied to the present day in New Mexico; although their populations shrank dramatically after European contact, their relationship to the Chaco culture has remained ambiguous. Until now, that is. People from one of these communities, Picuris Pueblo, worked with specialistsancient DNA to show that they are the closest relatives of the Chaco people yet discovered, confirming aspects of the pueblo’s oral traditions.

A pueblo-driven study

The list of authors of the new paper describing this genetic connection includes members of the Pueblo government, including its present governor. That’s because the study was initiated by the members of the Pueblo, who worked with archeologists to get in contact with DNA specialists at the Center for GeoGenetics at the University of Copenhagen. In a press conference, members of the Pueblo said they’d been aware of the power of DNA studies via their use in criminal cases and ancestry services. The leaders of Picuris Pueblo felt that it could help them understand their origin and the nature of some of their oral history, which linked them to the wider Pueblo-building peoples.

After two years of discussions, the collaboration settled on a plan of research, and the ancient DNA specialists were given access to both ancient skeletons at Picuris Pueblo, as well as samples from present-day residents. These were used to generate complete genome sequences.

The first clear result is that there is a strong continuity in the population living at Picuris. The ancient skeletons range from 500 to 700 years old, and thus date back to roughly the time of European contact, with some predating it. They also share strong genetic connections to the people of Chaco Canyon, where DNA has also been obtained from remains. “No other sampled population, ancient or present-day, is more closely related to Ancestral Puebloans from Pueblo Bonito [in Chaco Canyon] than the Picuris individuals are,” the paper concludes.

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Are these chimps having a fruity booze-up in the wild?

animal behavior, Biology, chimpanzees, primates, Science / /

Is there anything more human than gathering in groups to share food and partake in a fermented beverage or two (or three, or….)? Researchers have caught wild chimpanzees on camera engaging in what appears to be similar activity: sharing fermented African breadfruit with measurable alcoholic content. According to a new paper published in the journal Current Biology, the observational data is the first evidence of the sharing of alcoholic foods among nonhuman great apes in the wild.

The fruit in question is seasonal and comes from Treculia africana trees common across the home environment of the wild chimps in Cantanhez National Park in Guinea-Bissau. Once mature, the fruits drop from the tree to the ground and slowly ripen from a hard, deep green exterior to a yellow, spongier texture. Because the chimps are unhabituated, the authors deployed camera traps at three separate locations to record their feeding and sharing behavior.

They recorded 10 instances of selective fruit sharing among 17 chimps, with the animals exhibiting a marked preference for riper fruit. Between April and July 2022, the authors measured the alcohol content of the fruit with a handy portable breathalyzer and found almost all of the fallen fruit (90 percent) contained some ethanol, with the ripest containing the highest levels—the equivalent of 0.61 percent ABV (alcohol by volume).

That’s comparatively low to alcoholic drinks typically consumed by humans, but then again, fruit accounts for as much as 60 to 80 percent of the chimps’ diet, so the amount of ethanol consumed could add up quickly. It’s highly unlikely the chimps would get drunk, however. It wouldn’t confer any evolutionary advantage, and per the authors, there is evidence in the common ancestor of African apes of a molecular mechanism that increases the ability to metabolize alcohol.

Are these chimps having a fruity booze-up in the wild? Read More »

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Lichens can survive almost anything, and some might survive Mars

Biology, lichens, Mars, radiation resistance, Science / /

Whether anything ever lived on Mars is unknown. And the present environment, with harsh temperatures, intense radiation, and a sparse atmosphere, isn’t exactly propitious for life. Despite the red planet’s brutality, lichens that inhabit some of the harshest environments on Earth could possibly survive there.

Lichens are symbionts, or two organisms that are in a cooperative relationship. There is a fungal component (most are about 90 percent fungus) and a photosynthetic component (algae or cyanobacteria). To see if some species of lichen had what it takes to survive on Mars, a team of researchers led by botanist Kaja Skubała used the Space Research Center of the Polish Academy of Sciences to expose the lichen species Diploschistes muscorum and Cetrarea aculeata to simulate Mars conditions.

“Our study is the first to demonstrate that the metabolism of the fungal partner in lichen symbiosis was active while being in a Mars-like environment,” the researchers said in a study recently published in IMA Fungus. “X-rays associated with solar flares and SEPs reaching Mars should not affect the potential habitability of lichens on this planet.”

Martian ionizing radiation is threatening to most forms of life because it can cause damage at the cellular level. It can also get in the way of physical, genetic, morphological, and biochemical processes, depending on the organism and radiation level.

Going to extremes

Lichens have an edge when it comes to survival. They share characteristics with other organisms that can handle high levels of stress, including a low metabolism, not needing much in the way of nutrition, and longevity. Much like tardigrades, lichens can stay in a desiccated state for extended periods until they are rehydrated. Other lichen adaptations to extreme conditions include metabolites that screen out UV rays and melanin pigments that also defend against radiation.

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To regenerate a head, you first have to know where your tail is

Biology, planaria, regeneration, Science / /

Before a critical point in development, the animals failed to close the wound made by the cut, causing the two embryo halves to simply spew cells out into the environment. Somewhat later, however, there was excellent survival, and the head portion of the embryo could regenerate a tail segment. This tells us that the normal signaling pathways present in the embryo are sufficient to drive the process forward.

But the tail of the embryo at this stage doesn’t appear to be capable of rebuilding its head. But the researchers found that they could inhibit wnt signaling in these posterior fragments, and that was enough to allow the head to develop.

Lacking muscle

One possibility here is that wnt signaling is widely active in the posterior of the embryo at this point, blocking formation of anterior structures. Alternatively, the researchers hypothesize that the problem is with the muscle cells that normally help organize the formation of a stem-cell-filled blastema, which is needed to kick off the regeneration process. Since the anterior end of the embryo develops earlier, they suggest there may simply not be enough muscle cells in the tail to kick off this process at early stages of development.

To test their hypothesis, they performed a somewhat unusual experiment. They started by cutting off the tails of embryos and saving them for 24 hours. At that point, they cut the front end off tails, creating a new wound to heal. At this point, regeneration proceeded as normal, and the tails grew a new head. This isn’t definitive evidence that muscle cells are what’s missing at early stages, but it does indicate that some key developmental step happens in the tail within the 24-hour window after the first cut.

The results reinforce the idea that regeneration of major body parts requires the re-establishment of the signals that lay out organization of the embryo in development—something that gets complicated if those signals are currently acting to organize the embryo. And it clearly shows that the cells needed to do this reorganization aren’t simply set aside early on in development but instead take some time to appear. All of that information will help clarify the bigger-picture question of how these animals manage such a complex regeneration process.

Current Biology, 2025. DOI: 10.1016/j.cub.2025.03.065  (About DOIs).

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De-extinction company announces that the dire wolf is back

Biology, colossal, de-extinction, dire wolf, Science, wolves / /

On Monday, biotech company Colossal announced what it views as its first successful de-extinction: the dire wolf. These large predators were lost during the Late Pleistocene extinctions that eliminated many large land mammals from the Americas near the end of the most recent glaciation. Now, in a coordinated PR blitz, the company is claiming that clones of gray wolves with lightly edited genomes have essentially brought the dire wolf back. (Both Time and The New Yorker were given exclusive access to the animals ahead of the announcement.)

The dire wolf is a relative of the now-common gray wolf, with clear differences apparent between the two species’ skeletons. Based on the sequence of two new dire wolf genomes, the researchers at Colossal conclude that dire wolves formed a distinct branch within the canids over 2.5 million years ago. For context, that’s over twice as long as brown and polar bears are estimated to have been distinct species. Dire wolves are also large, typically the size of the largest gray wolf populations. Comparisons between the new genomes and those of other canids show that the dire wolf also had a light-colored coat.

That large of an evolutionary separation means there are likely a lot of genetic differences between the gray and dire wolves. Colossal’s internal and unpublished analysis suggested that key differences could be made by editing 14 different areas of the genome, with 20 total edits required. The new animals are reported to have had 15 variants engineered in. It’s unclear what accounts for the difference, and a Colossal spokesperson told Ars: “We are not revealing all of the edits that we made at this point.”

Nevertheless, the information that the company has released indicates that it was focused on recapitulating the appearance of a dire wolf, with an emphasis on large size and a white coat. For example, the researchers edited in a gene variant that’s found in gray wolf populations that are physically large, rather than the variant found in the dire wolf genome. A similar thing was done to achieve the light coat color. This is a cautious approach, as these changes are already known to be compatible with the rest of the gray wolf’s genome.

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We have the first video of a plant cell wall being built

Biology, cell wall, imaging, microscopy, plants, Science / /

Plant cells are surrounded by an intricately structured protective coat called the cell wall. It’s built of cellulose microfibrils intertwined with polysaccharides like hemicellulose or pectin. We have known what plant cells look like without their walls, and we know what they look like when the walls are fully assembled, but we’ve never seen the wall-building process in action. “We knew the starting point and the finishing point, but had no idea what happens in between,” says Eric Lam, a plant biologist at Rutgers University. He’s a co-author of the study that caught wall-building plant cells in action for the first time. And once we saw how the cell wall building worked, it looked nothing like how we drew that in biology handbooks.

Camera-shy builders

Plant cells without walls, known as protoplasts, are very fragile, and it has been difficult to keep them alive under a microscope for the several hours needed for them to build walls. Plant cells are also very light-sensitive, and most microscopy techniques require pointing a strong light source at them to get good imagery.

Then there was the issue of tracking their progress. “Cellulose is not fluorescent, so you can’t see it with traditional microscopy,” says Shishir Chundawat, a biologist at Rutgers. “That was one of the biggest issues in the past.” The only way you can see it is if you attach a fluorescent marker to it. Unfortunately, the markers typically used to label cellulose were either bound to other compounds or were toxic to the plant cells. Given their fragility and light sensitivity, the cells simply couldn’t survive very long with toxic markers as well.

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