Extraordinary underwater videos have captured orcas making sunfish explode by ramming them at high speed. The behaviour may help juvenile orcas feed by breaking the prey into many small pieces, but it also appears that the orcas may enjoy playing with their food.

“It’s a hunting tactic, but that involves a play game in the process,” says , an independent marine biologist in Mexico. “There’s ‘high-octane’ adrenaline and a lot of other hormones rushing through their bodies, so, of course, there’s got to be some sort of excitement.”

Sharp-tail sunfish (Masturus lanceolatus) are among the largest bony fish, weighing up to 2000 kilograms. Higuera had already seen groups of orcas (Orcinus orca) attacking sunfish in the Gulf of California, ripping off parts of their flesh and tossing them around to each other in a playful manner. In the past few years, he had even witnessed them .

Then, in July 2024, his colleague at US non-profit organisation Beneath the Waves caught an explosive interaction on her GoPro camera while diving in the Gulf of California. An adult female orca held onto a dead sunfish while an adult male orca swam upside down towards it at full speed. The female released the sunfish at the last second, and the male hit it with so much force that the fish burst into a flurry of small fragments.

A year later, tourist Hector Franz shot a similar underwater scene in the same bay. This time, an adult female rammed right-side-up into a sharp-tail sunfish held in place by another adult female, popping it into pieces. Combined, the two events mark the first time scientists have seen such behaviour by orcas, say Higuera, Ayres and their colleagues.

Sunfish have “an incredibly dense, rubbery, collagenous” outer layer that’s harder to bite through, so bursting them open could be an effective way to feed on them, says Higuera.

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“The explosive fragmentation seemed mostly to be of the stiff gelatinous capsule that makes up a high percentage – more than 80 per cent in large fish – of the body mass of the sunfish,” says at University College Cork in Ireland. “I suspect that calves cannot achieve enough force to do this, as their mass is too low. But they can exploit a cloud of objects that contain tasty morsels.”

Earlier sightings without full footage indicated that the entire pod was involved in a strategic attack process leading up to the rammings, says Higuera. The findings point to advanced cooperative hunting skills and even planning – especially adapting their techniques for different kinds of prey, he says.

Higuera suspects that popping the sunfish offered a learning experience for the calves, while providing them with bite-sized snacks. Simultaneously, these events could also reinforce social bonds through “play” and social learning in this highly intelligent species, he adds.

at the University of Tennessee in Knoxville says it is possible the orcas were having some fun in demolishing the fish, but play wouldn’t be the only goal, as there is clearly cooperative foraging going on as well.

“One of the fascinating things about play is that it can be a driver of behavioural innovation,” says at the University of Pisa, Italy. “It’s possible that a behaviour like this may have originated in a playful context and later acquired a feeding function, or vice versa. At this stage, we simply don’t know.”

A monkey with a distinctive mask-like face, found in a remote part of the Democratic Republic of the Congo, has been declared a new species – only the fifth new species of monkey documented from Africa in the past 75 years.

The monkey is known as likweli to local people who hunt it for bushmeat, and it has been given the scientific name Colobus congoensis. It lives in one of the most inaccessible parts of Africa, without paved roads or infrastructure.

“A typical expedition involves multiple modes of transportation: a flight, followed by a motorcycle ride, two days of hiking on foot and finally travel by dugout canoe to reach the monkey’s range,” says at Florida Atlantic University.

One of the most intriguing features of likweli is its facial appearance, says Detwiler. The light-coloured skin around the mouth and beneath the nose is unlike that of any other African colobus species, but resembles the facial pattern seen in some Asian colobine monkeys.

Detwiler and her colleagues believe the species’ mask-like face may represent ancestral traits that were present before the African and Asian colobine lineages diverged over 8 million years ago. “If so, likweli may have retained characteristics that were subsequently modified or lost in the other African colobus species,” says Detwiler.

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Like other colobus monkeys, likweli also has a distinctive body odour that defies description, she says.

Scientists first became aware of the species in 2008 when a team surveying on the banks of the Lomami river, in what is now Lomami National Park, took a photo that showed only a part of a monkey that had not been seen before, high in the canopy.

Then, in November 2018, another group again spotted the monkey, which is about 1.3 metres long and weighs around 7 kilograms. Between 2018 and 2022, there were 114 recorded observations of the new species, 25 of which were from vocalisations.

In 2021, several monkeys that had been killed by hunters for bushmeat were confiscated and handed over to researchers. Detailed morphological and genetic analysis confirmed they were indeed a wholly separate species. Genetic tests and recordings of their vocalisations also added to the evidence of their uniqueness.

“The genetic analyses revealed that likweli is a deeply divergent lineage that split from its closest known relative, Colobus satanas, approximately 4 to 5 million years ago,” says Detwiler. “That was much older than we expected and provided strong evidence that likweli represents a distinct species.”

Likweli is isolated from C. satanas by more than 1200 kilometres and several major river barriers. Unlike most other members of the genus, which have habitats exceeding 60,000 square kilometres, likweli is only known to exist in 1700 square kilometres of rainforest.

“Hunting is one of the primary threats facing likweli, particularly because the species has such a small known range and appears to occur at low densities,” says Detwiler.

Because of the risk of poaching and the monkey’s small population and home range, the team is proposing that the species should be listed as endangered. “Now that likweli has been recognised as a distinct species, another important step would be to grant it protected status under national law,” says Detwiler. “This would make it illegal to hunt the species, including in the buffer zone surrounding the park.”

There’s one scent to rule them all – and we now know what it is. A series of experiments has shown that a single molecule released by the queen of naked mole rat colonies prevents all the other females in a colony from breeding.

“It’s a super-contraceptive, if you’re a mole rat,” says at the Max Delbrück Center in Berlin.

Naked mole rats (Heterocephalus glaber) have a social structure like that of bees and ants, with colonies made up of soldiers and workers, and a single queen ruling each colony. Only the queen can breed, but how she maintains her long reign – Lewin’s team’s oldest queen is 39 – hasn’t been clear.

“The theory was that the queen is larger and more aggressive than the other animals, exerting her dominance through pushing and shoving,” says Lewin. “But we never found that very satisfying as an explanation.”

So team member , also at the Max Delbrück Center, proposed identifying the mole rat bouquet – the molecules in the air around them that create their scent. Comparing the scents of hundreds of animals revealed that only the queens produce a molecule called isopropyl myristate.

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“It’s made in the reproductive organs, basically the vagina of the reproductive female,” says Lewin.

When the team sprayed isopropyl myristate daily into cages containing male and female pairs, none of the females became pregnant. Without it, almost all the females became pregnant.

Next, the team removed a queen from a colony and applied isopropyl myristate daily. There were no fights for succession and no females started breeding during the three months this was done. “We produced peacefulness,” says Lewin. “That’s probably the most dramatic experiment.”

When the team stopped applying isopropyl myristate, the high-ranking females started fighting within a week. After around three weeks one became pregnant: the new queen.

The team also showed that exposure to isopropyl myristate changes the levels of the hormones progesterone and prolactin. But they haven’t found out exactly how the molecule is detected and leads to these changes – that’s the next project, says Lewin.

The evidence for isopropyl myristate influencing reproduction is compelling, says at Linnaeus University in Sweden. “I think it’s an impressive and important study. And convincing.”

at Queen Mary University of London is also convinced. “But the paper raises many questions, like any interesting research,” says Faulkes. These include how animals detect it, and how behavioural interactions and queen dominance interact with the scent, he says.

There is something special about isopropyl myristate, says Lewin. Isopropyl myristate is volatile, meaning it can evaporate into the air, but it’s not highly volatile, so any traces left by the queen take time to evaporate and the scent persists for at least a day.

It’s known that a queen will patrol every part of her colony, which in the wild might extend underground for 3 kilometres. “We think the reason she does that is to deposit this molecule around the colony,” says Lewin. “To make sure that every member of her colony is exposed to her scent.”

Other experiments by the team suggest the animals can consciously detect the smell. For instance, highly ranked females with a chance of becoming queen try to avoid places where isopropyl myristate is present, whereas lower-ranked animals aren’t bothered.

The team also tested a number of other species of mole rat. They didn’t find isopropyl myristate in any solitary species but they did find it in a few species whose social structure is more like that of naked mole rats. “But I would be cautious about assuming that the same pathway has a comparable function across social mole rats without direct experimental evidence,” says Zöttl.

Isopropyl myristate is also widely used in cosmetics. It is described as odourless but Lewin says some women at his lab thought they could smell something when exposed to it. A 2008 study also reported that during pregnancy and after childbirth.

The jaws of some sea worms are made of an exceptionally hard yet lightweight material dubbed a “bio-metal” that could have applications in engineering.

Perinereis cultrifera is a type of ragworm with a long body adorned with bristles. Members of the species also have strong jaws that enable them to crush hard prey such as small crustaceans or other worms. Remnants of their jaws have been found in the fossil record dating back to hundreds of millions of years ago.

at TU Wien in Austria and his colleagues have been studying this worm’s jaws for almost a decade, leading them to propose that they are made of a novel material. The molecular structure of each jaw combines proteins and ions of metals such as zinc, giving it characteristics in between those of softer biological materials and metals.

Most recently, the team performed more than 3300 experiments in which small indentations were made in different parts of the jaw. The way its hardness changed under this pressure followed a pattern typical of metals like copper and silver. But the jaw also exhibited a kind of elasticity that metals cannot have, says Hellmich.

Finally, the researchers developed a mathematical model of bio-metals, which shows how they might respond to strain in a unique way in which microscopic forces arise from the metal ions becoming arranged into lines similar to certain defects in crystals.

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The researchers were surprised to uncover so much novelty in the relatively simple animal. Performing mechanical tests on the millimetre-sized jaw was really challenging and required hundreds of hours of preparation and polishing, says Hellmich. “Basically, anything can go wrong,” he says.

“The jaws of bristle worms are incredibly hard yet very lightweight,” says at Kent State University in Ohio. “Many industries, from automobiles to aeronautics, are searching for new ways to develop hard and lightweight materials. The answers are provided in nature!”

“Somehow evolution figured out a way to coax a metal-like mechanical fingerprint out of protein-like ingredients, and studying the worm is how we ask what trick makes that possible,” says at the Massachusetts Institute of Technology, who didn’t work on the study. The long-term dream outcome of this research is to genetically program materials that would grow in biological systems, he says.

Hellmich and his colleagues are interested in pursuing this goal and their team already includes geneticists and biologists at the University of Vienna. “We are asking questions like, ‘If we knock out a few genes, then how will the jaws be different?’” he says.

A huntsman spider found in Queensland, Australia, has been crowned the fastest spider in the world with a top speed of nearly 3.6 metres per second, according to a global study of arachnid sprinting prowess.

Currently, is held by the Moroccan flic-flac spider (Cebrennus rechenbergi) which can hit speeds of 1.7 metres per second when it is startled, using a rolling-tumbling motion. But some experts regard this as incorrect.

“The flic-flac is a special type of locomotion,” says at University of Greifswald, Germany. “It is not running and it only works downhill on sand dunes.”

To get a comprehensive picture of running speed in spiders, Shreyas Kuchibhotla at Imperial College London and his colleagues, including Wolff, collected 162 live spider species during fieldwork throughout the UK, North America, southern Europe and Australia, along with dozens of specimens sourced from pet shops.

Each of these was carefully weighed then tested for their speed on A4 or A3 grid paper, in an attempt to understand the biomechanics across as many species as possible.

Most species were coaxed into running by gently touching them with a paintbrush, but others weren’t so cooperative, says Kuchibhotla. “This project would have been over in a month if spiders could understand English,” he says. “Tarantulas aren’t built for running; they’d much rather stand their ground, so they had to be blown at with puffs of compressed air.”

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Kuchibhotla and his colleagues also collected speed recordings of a further 96 species made by other research teams. The 3-gram jungle huntsman spider (Heteropoda jugulans) was by and his colleagues at the University of the Sunshine Coast in Australia.

These spiders can achieve such high speeds because they are “relatively large as far as spiders go, but not large enough that their legs get over- burdened by a heavy abdomen,” says Clemente.

In general, bigger spiders tended to be faster, but some are much faster than expected for their size. The biggest surprise was the orange goblin spider (Oonops pulcher), which weighs a mere 0.1 milligrams but moved at over 20 centimetres per second. “Nothing could have prepared me for how it practically teleported across the arena,” says Kuchibhotla.

, a team member at Imperial, says speed is, in principle, entirely determined by physics. But it is lifestyles such as hunting strategies that drive the evolution of extreme anatomical and physiological adaptations, he says.

“A cheetah, say, comfortably outruns most similarly sized dogs. This is, of course, because its lifestyle has made this speed beneficial, but it is still dictated by physics,” says Labonte.

After accounting for both body size and shared ancestry, the team’s conclusion is that fast running is associated with relatively longer legs but not with leg slenderness or, surprisingly, whether a spider lives its life upside down or not.

at Edith Cowan University in Perth, Australia, says long legs appear to be a spider’s “speed gear”. “The huntsman supplies the record-book hook, but the deeper discovery is that spider speed is shaped by leg architecture and evolutionary history, not simply by size or whether a spider spins a web,” says Mason.

Childbirth can be extremely challenging for humans – but some other primates may have it even worse. A comprehensive analysis of primate anatomy concludes that many species must squeeze large-headed infants through too-narrow pelvises. The problem may have begun with the very first primates, which lived more than 50 million years ago.

It has been assumed for decades that evolution has left humans with unique childbirth difficulties. The conventional view is that the trouble began when our ancestors first walked on two legs, which required the pelvis to be narrow. A few million years later, hominin brains evolved to be larger and infant heads became bigger – but the pelvis was unable to expand to allow for their easy delivery.

Other primates were thought to have things easier, largely because that was the conclusion of an published by anthropologist Adolph Schultz in the 1940s. Schultz looked at a range of primate species and concluded that in the vast majority, the infant head could fit comfortably through the female pelvis.

But his analysis was flawed, says at University College London. “One of the main problems was that it applied measurements that were originally developed for the human pelvis to all primates,” she says.

Schultz identified landmark points on the human pelvis that define the maximum width and depth of a horizontal plane at the top of the birth canal. He then assumed those same landmarks would define the maximum width and depth of any primate birth canal. They don’t. The human pelvis has a very unusual shape, and when Schultz’s landmarks are mapped onto other primate pelvises, they typically define an inclined plane that sits slightly above the birth canal. This plane overestimates the size of the birth canal, because it is effectively an oblique, oval-shaped slice through a cylinder representing the birth canal.

Torres-Tamayo and her colleagues reassessed birth canal shape in 29 primate species, while also looking at data on newborn-skull size and shape in each species. They concluded that several primates have a pelvis that seems too narrow to give birth. Small primates including bush babies and tamarins have the most severe conflict. In these primates, the newborn’s head is almost twice the size of the birth canal.

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“I was not expecting to have a mismatch in quite such a large number of primates,” says research team member , also at University College London.

Birth difficulties may even be the ancestral condition in primates, says Betti, particularly considering that early primates were small.

“It’s super cool to have such a big sample,” says at the University of Zurich, Switzerland. “These species are doing very different things, living in different niches and they do tend to be quite anatomically diverse.”

Different primates have also found their own solutions to the problem. For instance, the bush babies and tamarins dislocate the bones of the pelvis, temporarily doubling the size of the birth canal. Humans can’t do this, says Betti: it would make walking unbearably painful for a large, bipedal species.

Torres-Tamayo and Betti and their colleagues also found that birth difficulties are much less likely to arise in the great apes, maybe because they are so much larger than the tiny tree-dwelling primates. In this sense, humans are still unique in having birth difficulties, because we are the only large ape with the problem, says Betti.

But Webb isn’t so sure about this point; in a study she and her colleagues published in 2024, they concluded that between the size of the birth canal and the infant’s head. “That discrepancy is strange. It’s probably a reflection of the methods used,” says Webb. “This new paper is providing a really nice incentive for us to revisit our own hypothesis.”

A newly discovered spider in Australia builds a snare trap designed to catch a single species of ant, which launches the prey into its web with a g-force that would kill a human.

Researchers have measured accelerations of up to 1367 metres per second squared when green tree ants (Oecophylla smaragdina) trigger the web snare trap, equating to 130 times the force of gravity.

“To capture the moment, we had to push the cameras to 5000 to 7000 frames per second, which I honestly have never had to do… when I’ve been filming animals,” says at Macquarie University in Sydney.

In 2022, at QIMR Berghofer Medical Research Institute in Brisbane, Australia, witnessed a green tree ant being catapulted in a spider trap in the far north of Queensland.  But without the proper camera equipment, all he was able to observe was the blur of the prey being lifted ballistically by a strange-looking conical web.

Then, in early 2023, Narendra and , also at Macquarie University, spent 10 days studying and filming the nocturnal spiders, which do not yet have a scientific name but are in the genus Propostira.

They are nicknamed ballista spiders after a Roman, crossbow-like weapon that could launch large rocks hundreds of metres.

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The spiders spend the day hiding on the underside of leaves, then begin building the trap shortly after dusk, a process that can take up to four hours to complete. During this time, the spider sets between 15 and 60 tightly bunched tension lines that are attached to a leaf and form a conical shape.

After building the trap, it applies a kind of chemical that triggers the green tree ants, but not any other species, to attack the trap with their mandibles.

“I suspect that there is a lot of stickiness in the silk,” says Narendra. “The mandibles are not able to actually able to open up and let it go and release; they are glued stuck.”

As the ant struggles with the snare, it tries to pull itself free, releasing the trap’s anchor point. At this moment, the tension lines attached to the cone fling the ant nearly 30 centimetres into the air, where it becomes tangled in the spider’s main web.

It is likely that the spiders employ the strategy as a way to lift the prey up off the ants’ path through the forest, avoiding a dangerous counterattack from the colony, says Narendra.

It may seem like a lot of effort to build the trap for each meal, but green tree ants are an extremely reliable source of food, he says. “Whenever the spider needs to eat, it just steps out, builds the web, and it’ll have food coming in.”