According to Amazonian folklore, the area’s male river dolphins are shapeshifters (encantade), transforming at night into handsome young men who seduce and impregnate human women. The legend’s origins may lie in the fact that dolphins have rather human-like genitalia. A group of Canadian biologists didn’t spot any suspicious shapeshifting behavior over the four years they spent monitoring a dolphin population in central Brazil, but they did document 36 cases of another human-like behavior: what appears to be some sort of cetacean pissing contest.
Specifically, the male dolphins rolled over onto their backs, displayed their male members, and launched a stream of urine as high as 3 feet into the air. This usually occurred when other males were around, who seemed fascinated in turn by the arching streams of pee, even chasing after them with their snouts. It’s possibly a form of chemical sensory communication and not merely a need to relieve themselves, according to the biologists, who described their findings in a paper published in the journal Behavioral Processes. As co-author Claryana Araújo-Wang of CetAsia Research Group in Ontario, Canada, told New Scientist, “We were really shocked, as it was something we had never seen before.”
Spraying urine is a common behavior in many animal species, used to mark territory, defend against predators, communicate with other members of one’s species, or as a means of mate selection since it has been suggested that the chemicals in the urine carry useful information about physical health or social dominance.
Those results supported the initial hypothesis that chimps tended to urinate in sync rather than randomly. Further analysis showed that the closer a chimp was to another peeing chimp, the more likely the probability of that chimp peeing as well—evidence of social contagion. Finally, Onishi et al. wanted to explore whether social relationships (like socially close pairs, evidenced by mutual grooming and similar behaviors) influenced contagious urination. The only social factor that proved relevant was dominance, with less-dominant chimps being more prone to contagious urination.
There may still be other factors influencing the behavior, and more experimental research is needed on potential sensory cues and social triggers in order to identify possible underlying mechanisms for the phenomenon. Furthermore, this study was conducted with a captive chimp population; to better understand potential evolutionary roots, there should be research on wild chimp populations, looking at possible links between contagious urination and factors like ranging patterns, territory use, and so forth.
“This was an unexpected and fascinating result, as it opens up multiple possibilities for interpretation,” said coauthor Shinya Yamamoto, also of Kyoto University. “For instance, it could reflect hidden leadership in synchronizing group activities, the reinforcement of social bonds, or attention bias among lower-ranking individuals. These findings raise intriguing questions about the social functions of this behavior.”
Elaborate courtship, devoted parenthood, gregarious nature (and occasional cannibalism)—earwigs have a lot going for them.
Few people are fond of earwigs, with their menacing abdominal pincers—whether they’re skittering across your floor, getting comfy in the folds of your camping tent, or minding their own business.
Scientists, too, have given them short shrift compared with the seemingly endless attention they have lavished on social insects like ants and bees.
Yet, there are a handful of exceptions. Some researchers have made conscious career decisions to dig into the hidden, underground world where earwigs reside, and have found the creatures to be surprisingly interesting and social, if still not exactly endearing.
Work in the 1990s and early 2000s focused on earwig courtship. These often intricate performances of attraction and repulsion—in which pincers and antennae play prominent roles—can last hours, and the mating itself as long as 20 hours, at least in one Papua New Guinea species, Tagalina papua. The females usually decide when they’ve had enough, though males of some species use their pincers to restrain the object of their desire.
Males of the bone-house earwig Marava arachidis (often found in bone meal plants and slaughterhouses) are particularly coercive, says entomologist Yoshitaka Kamimura of Keio University in Japan, who has studied earwig mating for 25 years. “They bite the female’s antennae and use a little hook on their genitalia to lock them inside her reproductive tract.”
Size matters
Female earwigs collect sperm in one or more internal pouches and can use it to fertilize multiple broods, so they don’t need to mate again. The only thing most males can do is add their own sperm, but Kamimura has seen males of the pale-legged earwig Euborellia pallipesremove the sperm of other males using an elongated part of their peculiar penis.
It’s better if females can prevent this from happening, because they can be particular about the males they mate with. This may explain why, in some species, male and female genitalia have increased in size as part of a kind of evolutionary arms race in which males benefit from access to the pouch and females benefit from keeping them out. In the bristly earwig Echinosoma horridum, the male’s genitalia are nearly as long as the rest of his body, and the female’s genitalia almost four times as long as the rest of hers.
Fascinating though they are, the amorous adventures of earwigs weren’t what first caught Kamimura’s attention. Rather, he was intrigued by the female’s dedication to her offspring. “When I was a student, I accidentally disturbed an earwig caring for her eggs in our backyard,” he recalls. “She ran away but returned the next day. I was very interested, and I started to rear them.”
Grow your own earwigs
The care that female earwigs provide to their eggs has also become the focus of study in Europe, where a surge of lab research on European earwigs—Forficula auricularia—was kick-started almost 20 years ago by entomologist Mathias Kölliker at the University of Basel, Switzerland. “Getting them to breed continuously over multiple generations was a big challenge,” he recalls. “The females did lay eggs, but they didn’t develop, and never hatched.”
It turned out that the eggs, which are laid in late fall and hatch in January, need the winter cold to start their development. So the scientists figured out a lab regimen that would chill but not kill the eggs. “That took us about two years,” says Kölliker.
In 2009, Kölliker hired entomologist Joël Meunier, who continues to study earwigs at the University of Tours in France and wrote an overview of the biology and social life of earwigs for the Annual Review of Entomology. Earwigs are high maintenance, he says. “If you work with fruit flies, you can breed 10 generations in a few months, but earwigs take much longer.… And they’re all kept in separate petri dishes—thousands of them—that we have to open twice a week to replace the food.
“I think this is one of the reasons few people work on them. But they’re very fascinating.”
Fending off males
The female’s careful egg grooming has at least two important functions. First, she uses a small brush on her mouthparts to remove the spores of fungi that can kill the eggs. Secondly, as Kölliker, Meunier, and colleagues found, she applies water-repellent hydrocarbons to keep them from drying out.
Males that attempt to approach the nest are aggressively chased away, and with good reason, says Meunier. “Once, when we were in the field in Italy to collect earwigs, we found a male and a female together with a clutch of eggs. We were quite excited: ‘Wow, biparental care, cool!’ So we brought them to the lab. But what we actually observed was that the female was very stressed out, showing a lot of aggression towards the male, while the clutch size was continuously decreasing.”
Males, it turns out, love to snack on eggs, even ones that they fathered. To chase them off, females raise their abdomens to show off their pincers. If that’s not enough, they can use the pincers to hurt the male—even to cut him in half. (Scary as they look, the pincers can’t harm people at all, Meunier says.)
Earwigs can also spray each other with defensive secretions that may have antimicrobial properties, too. “They often use those secretions when meeting others,” says Meunier. “Maybe it also prevents the spread of disease.”
As far as scientists know, these secretions are harmless to humans. But because they contain quinone derivatives, which are also found in substances like henna, they have some quirky side effects. “When you get a lot of it on your hands,” Meunier says, “they’ll turn blue, like a bruise, and these marks can last all week.”
The secretions smell quite pleasant, says Kölliker. “When I had a visitor in the lab, I would sometimes pick up an earwig and hold it under their nose. It’s a very nice odor, actually, kind of an earthy smell.” Kölliker’s cat was less appreciative when he tried it on her: “She immediately backed off,” he says.
“In the best case, the mother’s presence doesn’t change a thing,” says Meunier. “At worst, nymphs that grow up with their mother are less likely to reach adulthood and will become smaller adults.” It’s unclear why. But things may be different in the wild, where male earwigs or predators like spiders pose threats, making it safer to stay with mom.
The mother herself seems to benefit. Meunier has observed that as soon as the nymphs emerge, they eat the parasitic mites that often bother breeding females. And once they start foraging on their own, the feces they leave all over the nest may be food for their mother and help her to produce a second brood. The nymphs also feast on each other’s feces, sometimes straight from the source.
The voracious nymphs don’t stop there: They regularly eat each other, and nymphs of the hump earwig Anechura harmandi will almost always eat their mother. “It occurs in every family,” Meunier says, “and it helps the nymphs grow.”
Let’s get together
With all this aggression and cannibalism, you’d expect adult earwigs not actively seeking mates to avoid each other, and in many species, they do. Yet European earwigs regularly group together by the hundreds, sometimes mixing things up with other earwig species.
And the hose-showering behavior was “lateralized,” that is, Mary preferred targeting her left body side more than her right. (Yes, Mary is a “left-trunker.”) Mary even adapted her showering behavior depending on the diameter of the hose: she preferred showering with a 24-mm hose over a 13-mm hose and preferred to use her trunk to shower rather than a 32-mm hose.
It’s not known where Mary learned to use a hose, but the authors suggest that elephants might have an intuitive understanding of how hoses work because of the similarity to their trunks. “Bathing and spraying themselves with water, mud, or dust are very common behaviors in elephants and important for body temperature regulation as well as skin care,” they wrote. “Mary’s behavior fits with other instances of tool use in elephants related to body care.”
Perhaps even more intriguing was Anchali’s behavior. While Anchali did not use the hose to shower, she nonetheless exhibited complex behavior in manipulating the hose: lifting it, kinking the hose, regrasping the kink, and compressing the kink. The latter, in particular, often resulted in reduced water flow while Mary was showering. Anchali eventually figured out how to further disrupt the water flow by placing her trunk on the hose and lowering her body onto it. Control experiments were inconclusive about whether Anchali was deliberately sabotaging Mary’s shower; the two elephants had been at odds and behaved aggressively toward each other at shower times. But similar cognitively complex behavior has been observed in elephants.
“When Anchali came up with a second behavior that disrupted water flow to Mary, I became pretty convinced that she is trying to sabotage Mary,” Brecht said. “Do elephants play tricks on each other in the wild? When I saw Anchali’s kink and clamp for the first time, I broke out in laughter. So, I wonder, does Anchali also think this is funny, or is she just being mean?
For several months in 1898, a pair of male lions turned the Tsavo region of Kenya into their own human hunting grounds, killing many construction workers who were building the Kenya-Uganda railway. A team of scientists has now identified exactly what kinds of prey the so-called “Tsavo Man-Eaters” fed upon, based on DNA analysis of hairs collected from the lions’ teeth, according to a recent paper published in the journal Current Biology. They found evidence of various species the lions had consumed, including humans.
The British began construction of a railway bridge over the Tsavo River in March 1898, with Lieutenant-Colonel John Henry Patterson leading the project. But mere days after Patterson arrived on site, workers started disappearing or being killed. The culprits: two maneless male lions, so emboldened that they often dragged workers from their tents at night to eat them. At their peak, they were killing workers almost daily—including an attack on the district officer, who narrowly escaped with claw lacerations on his back. (His assistant, however, was killed.)
Patterson finally managed to shoot and kill one of the lions on December 9 and the second 20 days later. The lion pelts decorated Patterson’s home as rugs for 25 years before being sold to Chicago’s Field Museum of Natural History in 1924. The skins were restored and used to reconstruct the lions, which are now on permanent display at the museum, along with their skulls.
Tale of the teeth
The Tsavo Man-Eaters naturally fascinated scientists, although the exact number of people they killed and/or consumed remains a matter of debate. Estimates run anywhere from 28–31 victims to 100 or more, with a 2009 study that analyzed isotopic signatures of the lions’ bone collagen and hair keratin favoring the lower range.
In 2014, researchers monitoring acoustic recordings from the Mariana Archipelago picked up an unusual whale vocalization with both low- and high-frequency components. It seemed to be a whale call, but it sounded more mechanical than biological and has since been dubbed a “biotwang.”
Now a separate team of scientists has developed a machine-learning model to scan a dataset of recordings of whale vocalizations from various species to help identify the source of such calls. Combining that analysis with visual observations allowed the team to identify the source of the biotwang: a species of baleen whales called Bryde’s (pronounced “broodus”) whales. This should help researchers track populations of these whales as they migrate to different parts of the world, according to a recent paper published in the journal Frontiers in Marine Science.
Marine biologists often rely on a powerful tool called passive acoustic monitoring for long-term data collection of the ocean’s acoustic environment, including whale vocalizations. Bryde’s whale calls tend to be regionally specific, per the authors. For instance, calls in the eastern North Pacific are pretty well documented, with frequencies typically falling below 100 Hz, augmented by harmonic frequencies as high as 400 Hz. Far less is known about the sounds made by Bryde’s whales in the western and central North Pacific, since for many years there were only three known recordings of those vocalizations—including a call dubbed “Be8” (starting at 45 Hz with multiple harmonics) and mother-calf calls.
That changed with the detection of the biotwang in 2014. It’s quite a distinctive, complex call that typically lasts about 3.5 seconds, with five stages, starting at around 30 Hz and ending with a metallic sound that can reach as high as 8,000 Hz. “It’s a real weird call,” co-author Ann Allen, a scientist at NOAA Fisheries, told Ars. “Anybody who wasn’t familiar with whales would think it was some sort of artificial sound, made by a naval ship.” The 2014 team was familiar with whale vocalizations and originally attributed the strange sound to baleen whales. But that particular survey was autonomous, and without accompanying visual observations, the scientists could not definitively confirm their hypothesis.
Enlarge/ “The only species of fish confirmed to be able to escape from the digestive tract of the predatory fish after being captured.”
Hasegawa et al./Current Biology
Imagine you’re a Japanese eel, swimming around just minding your own business when—bam! A predatory fish swallows you whole and you only have a few minutes to make your escape before certain death. What’s an eel to do? According to a new paper published in the journal Current Biology, Japanese eels opt to back their way out of the digestive tract, tail first, through the esophagus, emerging from the predatory fish’s gills.
Per the authors, this is the first such study to observe the behavioral patterns and escape processes of prey within the digestive tract of predators. “At this point, the Japanese eel is the only species of fish confirmed to be able to escape from the digestive tract of the predatory fish after being captured,” co-author Yuha Hasegawa at Nagasaki University in Japan told New Scientist.
There are various strategies in nature for escaping predators after being swallowed. For instance, a parasitic worm called Paragordius tricuspidatus can force its way out of a predator’s system when its host organism is eaten. There was also a fascinating study in 2020 by Japanese scientists on the unusual survival strategy of the aquatic beetle Regimbartia attenuata. They fed a bunch of the beetles to a pond frog (Pelophylax nigromaculatus) under laboratory conditions, expecting the frog to spit the beetle out. That’s what happened with prior experiments on bombardier beetles (Pheropsophus jessoensis), which spray toxic chemicals (described as an audible “chemical explosion”) when they find themselves inside a toad’s gut, inducing the toad to invert its own stomach and vomit them back out.
But R. attenuata basically walks through the digestive tract and escapes out of the frog’s anus after being swallowed alive. It proved to be a successful escape route. In the case of the bombardier beetles, between 35 and 57 percent of the toads threw up within 50 minutes on average, ensuring the survival of the regurgitated beetles. R. attenuata‘s survival rate was a whopping 93 percent. In fact, 19 out of 20 walked out of the frog, unharmed, within an hour, although one industrious beetle bolted out in just five minutes. Granted, the beetles often emerged covered in fecal pellets, which can’t have been pleasant. But that didn’t stop them from resuming their little beetle lives; all survived at least two weeks after being swallowed.
Hasegawa co-authored an earlier study in which they observed Japanese eels emerging from a predator’s gills after being swallowed, so they knew this unique strategy was possible. They just didn’t know the details of what was going on inside the digestive tract that enabled the eels to pull off this feat. So the team decided to use X-ray videography to peer inside predatory fish (Odontobutis obscura) after eels had been eaten. They injected barium sulfate into the abdominal cavity and tail of the Japanese eels as a contrast agent, then introduced each eel to a tank containing one O. obscura. The X-ray video system captured the interactions after an eel had been swallowed.
Out through the gills
The escaping behavior of a Japanese eel. Credit: Hasegawa et al./Current Biology
O. obscura swallow their prey whole along with surrounding water, and a swallowed eel quickly ends up in the digestive tract, a highly acidic and oxygen-deprived environment that kills the eels within 211.9 seconds (a little over three minutes). Thirty-two of the eels were eaten, and of those, 13 (or 40.6 percent) managed to poke at least their tails through the gills of their predator. Of those 13, nine (69.2 percent) escaped completely within 56 seconds on average, suggesting “that the period until the tails emerge from the predator’s gill is particularly crucial for successful escape,” the authors wrote. The final push for freedom involved coiling their bodies to extract their head from the gill.
It helps to be swallowed head-first. The researchers discovered that most captured eels tried to escape by swimming back up the digestive tract toward the esophagus and gills, tail-first in the cases where escape was successful. However, eleven eels ended up completely inside the stomach and resorted to swimming around in circles—most likely looking for a possible escape route. Five of those managed to insert their tails correctly toward the esophagus, while two perished because they oriented their tails in the wrong direction.
“The most surprising moment in this study was when we observed the first footage of eels escaping by going back up the digestive tract toward the gill of the predatory fish,” said co-author Yuuki Kawabata, also of Nagasaki University. “At the beginning of the experiment, we speculated that eels would escape directly from the predator’s mouth to the gill. However, contrary to our expectations, witnessing the eels’ desperate escape from the predator’s stomach to the gills was truly astonishing for us.”
Enlarge/ As female macaques age, the size of their social network shrinks.
Walnut was born on June 3, 1995, at the start of what would become an unusually hot summer, on an island called Rum (pronounced room), the largest of the Small Isles off the west coast of Scotland. We know this because since 1974, researchers have diligently recorded the births of red deer like her, and caught, weighed and marked every calf they could get their hands on—about 9 out of every 10.
Near the cottage in Kilmory on the northern side of the island where the researchers are based, there has been no hunting since the project began, which allowed the deer to relax and get used to human observers. Walnut was a regular there, grazing the invariably short-clipped grass in this popular spot. “She would always just be there in the group, with her sisters and their families,” says biologist Alison Morris, who has lived on Rum for more than 23 years and studies the deer year-round.
Walnut raised 14 offspring, the last one in 2013, when she was 18 years old. In her later years, Morris recalls, Walnut would spend most of her time away from the herd, usually with Vanity, another female (called a hind) of the same age who had never calved. “They were often seen affectionately grooming each other, and after Walnut died of old age in October 2016, at the age of 21—quite extraordinary for a hind—Vanity spent most of her time alone. She died two years later, at the grand age of 23.”
Are old hinds left behind?
Such a shift in social life is common in aging red deer females, says ecologist Gregory Albery, now at Georgetown University in Washington, DC, who spent months on the island studying the deer during his PhD training. (Males roam around more and associate less consistently with others, so they are harder to study.) “Older females tend to be observed in the company of fewer others. That was easy to establish,” he says. “The more difficult question to answer has been why we are seeing this pattern, and what it means.”
The first question one should ask, Albery says, is whether individual deer alter their behavior to associate with fewer others as they age, or whether individuals that associate with fewer others tend to live to an older age. This is the kind of question that many researchers are unable to answer when simply comparing individuals of different ages. But long-term studies like the one at Rum can do so through long-term tracking of populations. Forty times a year, the deer are censused by fieldworkers like Morris who recognize the deer on sight and meticulously note where they are and with whom.
When they accounted for the age and survival of the deer in their analysis, Albery and colleagues found that the link between age and number of associates remained solid: Social connections do, indeed, decrease as individuals age. Might this be because many of the older deer’s friends have died? On the contrary, Albery and colleagues found that older deer who had recently lost friends tended to hang out with others more often.
So why do old hinds have fewer contacts? Part of the explanation may be that they don’t range as widely as they grow older. Studying the deer for a couple of months would not have exposed this trend, says Albery: It was only revealed by tracking the same individuals through time. “Deer with a larger home range generally live longer,” he explains, so an analysis at any single point in time would show larger ranges for older deer and suggest that home ranges expand with age. Tracking individuals through time reveals the opposite is true. “Their home ranges decrease in size as they age,” Albery says.
It is unlikely that older deer move around less because they are concentrating on the core of their favorite habitat, says Albery. The center of their range shifts with age, and they are observed more often in taller and probably less nutritious vegetation, away from the most popular spots. This indicates there might be some kind of competitive exclusion going on: Perhaps more energetic, younger deer with offspring to feed are colonizing the best grazing patches.
On the other hand, older deer may also have different preferences. “Perhaps the longer grasses are easier to eat when your incisors are too worn to clip the short grass everyone else is after,” Albery says. Plus the deer don’t have to bend over as far to reach the longer grass.
A recent study by Albery and colleagues in Nature Ecology & Evolution found that older deer reduce their contacts more than you’d expect if their shrinking range was the only cause. That suggests the behavior may have evolved for a reason—one that Albery prosaically summarizes as, “Deer shit where they eat.”
Gastrointestinal worms are rampant on the island. And though the deer do not get infected through direct contact with others, being at the same place at the same time probably does increase their risk of ingesting eggs or larvae in the still-warm droppings of one of their associates.
“Younger animals need to put themselves out there to make friends, but perhaps when you’re older and you already have some, the risk of disease just isn’t worth it,” says study coauthor Josh Firth, a behavioral ecologist at the University of Oxford.
In addition, says ecologist Daniel Nussey of the University of Edinburgh, another coauthor, “there are indications that the immune system of aging deer is less effective in suppressing worm infections, so they might be more likely to die from them.”
Enlarge/ Ariel and Caliban learned as kittens that scratching posts were fair game for their natural claw-sharpening instincts.
Sean Carroll
Ah, cats. We love our furry feline overlords despite the occasional hairball and their propensity to scratch the furniture to sharpen their claws. The latter is perfectly natural kitty behavior, but overly aggressive scratching is usually perceived as a behavioral problem. Veterinarians frown on taking extreme measures like declawing or even euthanizing such “problematic” cats. But there are alternative science-backed strategies for reducing or redirecting the scratching behavior, according to the authors of a new paper published in the journal Frontiers in Veterinary Science.
This latest study builds on the group’s prior research investigating the effects of synthetic feline facial pheromones on undesirable scratching in cats, according to co-author Yasemin Salgirli Demirbas, a veterinary researcher at Ankara University in Turkey. “From the beginning, our research team agreed that it was essential to explore broader factors that might exacerbate this issue, such as those influencing stress and, consequently, scratching behavior in cats,” she told Ars. “What’s new in this study is our focus on the individual, environmental, and social dynamics affecting the level of scratching behavior. This perspective aims to enhance our understanding of how human and animal welfare are interconnected in different scenarios.”
The study investigated the behavior of 1,211 cats, with data collected via an online questionnaire completed by the cats’ caregivers. The first section collected information about the caregivers, while the second asked about the cats’ daily routines, social interactions, environments, behaviors, and temperaments. The third and final section gathered information about the frequency and intensity of undesirable scratching behavior in the cats based on a helpful “scratching index.”
The team concluded that there are several factors that influence the scratching behavior of cats, including environmental factors, high levels of certain kinds of play, and increased nocturnal activity. But stress seems to be the leading driver. “Cats might scratch more as a way to relieve stress or mark their territory, especially if they feel threatened or insecure,” said Demirbas. And the top source of such stress, the study found, is the presence of small children in the home.
Enlarge/ A corrugated fiberboard scratching pad can redirect your cat’s unwanted scratching away from the furniture.
Enlarge/ Extreme sportsman Ross Edgley comes face to face with a great hammerhead shark in the waters of Bimini in the Bahamas.
National Geographic/Nathalie Miles
Ultra-athlete Ross Edgley is no stranger to pushing his body to extremes. He once ran a marathon while pulling a one-ton car; ran a triathlon while carrying a 100-pound tree; and climbed a 65-foot rope over and over again until he’d climbed the equivalent of Mt. Everest—all for charity. In 2016, he set the world record for the world’s longest staged sea swim around the coastline of Great Britain: 1780 miles over 157 days.
At one point during that swim, a basking shark appeared and swam alongside Edgley for a day and a half. That experience ignited his curiosity about sharks and eventually led to his new National Geographic documentary, Shark vs. Ross Edgley—part of four full weeks of 2024 SHARKFEST programming. Edgley matches his athletic prowess against four different species of shark. He tries to jump out of the water (polaris) like a great white shark; withstand the G forces produced by a hammerhead shark‘s fast, rapid turns; mimic the extreme fasting and feasting regimen of a migrating tiger shark; and match the swimming speed of a mako shark.
“I love this idea of having a goal and then reverse engineering and deconstructing it,” Edgley told Ars. “[Sharks are] the ultimate ocean athletes. We just had this idea: what if you’re crazy enough to try and follow in the footsteps of four amazing sharks? It’s an impossible task. You’re going to fail, you’re going to be humbled. But in the process, we could use it as a sports/shark science experiment, almost like a Trojan horse to bring science and ocean conservation to a new audience.”
And who better than Edgley to take on that impossible challenge? “The enthusiasm he brings to everything is really infectious,” marine biologist and shark expert Mike Heithaus of Florida International University told Ars. “He’s game to try anything. He’d never been in the water with sharks and we’re throwing him straight in with big tiger sharks and hammerheads. He’s loving the whole thing and just devoured all the information.”
That Edgley physique doesn’t maintain itself, so the athlete was up at 4 AM swimming laps and working out every morning before the rest of the crew had their coffee. “I’m doing bicep curls with my coffee cup and he’s doing bicep curls with the 60-pound underwater camera,” Heithaus recalled. “For the record, I got one rep in and I’m very proud of that.” Score one for the shark expert.
(Spoilers below for the various shark challenges.)
Ross vs. the great white shark
Ross Edgley gets some tips on how to power (polaris) his body out of the water like a white shark from synchronized swimmer Samantha Wilson
National Geographic/Nathalie Miles
The Aquabatix synchronized swim team demonstrates the human equivalent to a white shark’s polaris.
National Geographic/Nathalie Miles
Edgley tries out a mono fin to improve his polaris performance.
National Geographic/Nathalie Miles
Edgley propelling 3/4 of his body out of the pool to mimic a white shark’s polaris movement
National Geographic/Bobby Cross
For the first challenge, Edgley took on the great white shark, a creature he describes as a “submarine with teeth.” These sharks are ambush hunters, capable of propelling their massive bodies fully out of the water in an arching leap. That maneuver is called a polaris, and it’s essential to the great white shark’s survival. It helps that the shark has 65 percent muscle mass, particularly concentrated in the tail, as well as a light skeleton and a large liver that serves as buoyancy device.
Edgley, by comparison, is roughly 45 percent muscle mass—much higher than the average human but falling short of the great white shark. To help him try to match the great white’s powerful polaris maneuver, Edgley sought tips on biomechanics from the Aquabatix synchronized swim team, since synchronized swimmers must frequently launch their bodies fully out of the water during routines. They typically get a boost from their teammates to do so.
The team did manage to boost Edgley out of the water, but sharks don’t need a boost. Edgley opted to work with a monofin, frequently used in underwater sports like free diving or finswimming, to see what he could achieve on his own power. After a bit of practice, he succeeded in launching 75 percent of his body (compared to the shark’s 100 percent) out of the water. Verdict: Edgley is 75 percent great white shark.
Ross vs. the hammerhead shark
Edgley vs. a hammerhead shark. He will try to match the animal’s remarkable agility underwater.
National Geographic/Nathalie Miles
A camera team films a hammerhead shark making sharp extreme turns
National Geographic/Nathalie Miles
Edgley prepares to go airborne in a stunt plane to try and mimic the agility of a hammerhead shark in the water.
National Geographic/Nathalie Miles
A standard roll produces 2 g’s, while pulling up is 3 g’s
YouTube/National Geographic
Edgley is feeling a bit queasy.
YouTube/National Geographic
Next up: Edgley pitted himself against the remarkable underwater agility of a hammerhead shark. Hammerheads are known for being able to swim fast and turn on a dime, thanks to a flexible skeleton that enables them to bend and contort their bodies nearly in half. They’re able to withstand some impressive G forces (up to 3 G’s) in the process. According to Heithaus, these sharks feed on other rays and other sharks, so they need to be built for speed and agility—hence their ability to accelerate and turn rapidly.
The NatGeo crew captured impressive underwater footage of the hammerheads in action, including Edgley meeting a 14.7 hammerhead named “Queenie”—one of the largest great hammerheads that visits Bimini in the Bahamas during the winter. That footage also includes shots of divers feeding fish to some of the hammerheads by hand. “They know every shark by name and the sharks know the feeders,” said Heithaus. “So you can safely get close to these big amazing creatures.”
For years, scientists had wondered about the purpose of the distinctive hammer-shaped head. It may help them scan a larger area of the ocean floor while hunting. Like all sharks, hammerheads have sensory pores called ampullae of Lorenzini that allow them to detect electrical signals and hence possible prey. The hammer-shaped head distributes those pores over a wider span.
But according to Heithaus, the hammer shape also operates a bit like the big broad flap of an airplane wing, resulting in excellent hydrodynamics. Moving at high speeds, “You can just tilt the head a tiny bit and bank a huge degree,” he said. “So if a ray turns 180 degrees to escape, the hammerhead can track with it. Other species would take a wider turn and fall behind.”
The airplane wing analogy gave Edgley an idea for how he could mimic the tight turns and high G forces of a hammerhead shark: take a flight in a small stunt plane. The catch: Edgley is not a fan of flying. And as he’d feared, he became horribly airsick during the challenge, even puking into a little airbag at one point. “It looks so cool in the clip,” he said. “But at the time, I was in a world of trouble.” Pilot Mark Greenfield finally cut the experiment short when he determined that Edgley was too sick to continue. Verdict: Edgley is 0 percent hammerhead shark.
Ross vs. the tiger shark
Shark expert Mike Heithaus holds a gelatin shark “lolliop” while Edgley flexes.
National Geographic/Nathalie Miles
Edgley and Heithaus underwater with a tiger shark, tempting it with a gelatin lollipop.
National Geographic/Nathalie Miles
Success! A tiger shark takes a nice big bite.
National Geographic/Nathalie Miles
Edgley flexes with the giant gelatin lollipop with a large bite taken out of it by a tiger shark
National Geographic/Nathalie Miles
Edgley gets his weight and body volume measured in the “Bodpod” before his tiger shark challenge.
National Geographic/Bobby Cross
Edgley fasted and exercised for 24 hours to mimic a tiger shark on a migration route. He dropped 14 pounds.
National Geographic/Nathalie Miles
After all that fasting and exercise, Edgley then gorged himself for 24 hours to put the weight back on. He gained 22 pounds.
National Geographic/Nathalie Miles
The third challenge was trying to match the fortitude of a migrating tiger shark as it makes its way over thousands of miles without food, only feasting at journey’s end. “I was trying to understand the psychology of a tiger shark because there’s just nothing for them to eat [on the journey],” said Ross. And once they arrive at their destination, “they can chow down on entire whale carcasses and eat just about anything. That idea of feast and famine is something we humans used to do all the time. We live quite comfortably now so we’ve lost touch with that.”
The first step was to figure out just how many calories a migrating tiger shark can consume in a single bite. Heithaus has been part of SHARKFEST for several years now and recalled one throwback show, Sharks vs. Dolphins, in which he tried to determine which species of of shark were attacking dolphins, and just how big those sharks might be. He hit upon the idea of making a dolphin shape out of gelatin—essentially the same stuff FIU’s forensic department uses for ballistic tests—and asked his forensic colleagues to make one for him, since the material has the same weight and density of dolphin blubber.
For the Edgley documentary, they made a large gelatin lollipop the same density as whale blubber, and he and Edgley dove down and managed to get an 11-foot tiger shark to take a big 6.2-pound bite out of it. We know how many calories are in whale blubber so Heithaus was able to deduce from that how many calories per bite a tiger shark consumed (6.2 pounds of whale meet is equivalent to about 25,000 calories).
Such field work also lets him gather ever mire specimens of shark bites from a range of species for his research. “The great thing about SHARKFEST is that you’re seeing new, cutting-edge science that may or may not work,” said Heithaus. “But that’s what science is about: trying things and advancing our knowledge even if it doesn’t work al the time, and then sharing that information and excitement with the public.”
Then it was time for Edgley to make like a migrating shark and embark on a carefully designed famine-and-feast regime. First, his weight and body volume were measured in a “Bodpod”: 190.8 pounds and 140.8 pints. Then Edgley fasted and exercised almost continuously for 24 hours with a mix of weight training, running, swimming, sitting in the sauna, and climate chamber cycling. (He did sleep for a few hours.) He dropped 14 pounds and lost twelve pints, ending up at a weight of 177 pounds and a volume of 128.7 pints. Instead of food, what he craved most at the end was water. “When you are in a completely deprived state, you find out what your body actually needs, not what it wants,” said Edgley.
After slaking his thirst, it was time to gorge. Over the next 24 hours, Edgley consumed an eye-popping 35,103 calories in carefully controlled servings. It’s quite the menu: Haribo mix, six liters of Lucozade, a Hulk smoothie, pizza, five slices of lemon blueberry cheesecake, five slices of chocolate mint cheesecake, fish and chips, burgers and fries, two cinnamon loaves, four tubs of Ben & Jerry’s ice cream, two full English breakfasts, five liters of custard, four mars bars, and four mass gainer shakes.
When his weight and volume were measured one last time in the Bodpod, Edgley had regained a whopping 22 pounds for a final weight of 199 pounds. “I wish I had Ross’s ability to eat that much and remain at 0 percent body fat,” said Heithaus. Verdict: Edgley is 28 percent tiger shark.
Ross vs. the mako shark
In 2018, Edgely set the world record for longest assisted sea swim.
National Geographic/Nathalie Miles
Edgley tries to match the speed of a mako shark in the waters of the Menai Strait in Wales.
National Geographic/Nathalie Miles
Finally, Edgley pitted himself against the mighty mako shark. Mako sharks are the speediest sharks in the ocean, capable of swimming at speeds up to 43 MPH. Edgley is a long-distance swimmer, not a sprinter, so he threw himself into training at Loughborough University with British Olympians coaching him. He fell far short of a mako shark’s top speed. The shape of the human body is simply much less hydrodynamic than that of a shark. He realized that despite his best efforts, “I was making up hundredths of a second, which is huge in sprinting,” he said. “That could be the difference between a gold medal at the Paris Olympics and not. But I needed to make up many kilometers per hour.”
So Edgley decided to “think like a shark” and employ a shark-like strategy of riding the ocean currents to increase his speed. He ditched the pool and headed to the Menai Strait in Wales for some open water swimming. Ultimately he was able to hit 10.24 MPH—double what an Olympic swimmer could manage in a pool, but just 25 percent of a mako shark’s top speed. And he managed with the help or a team of 20-30 people dropping him into the fastest tide possible. “A mako shark would’ve just gone, ‘This is a Monday morning, this isn’t an event for me, I’m off,'” said Edgley. Verdict: Edgley is 24 percent mako shark
When the results of all four challenges were combined, Edgley came out at 32 percent overall, or nearly one-third shark. While Edgley confessed to being humbled by his limitations, “I don’t think there’s anyone else out there who could do so as well across the board in comparison,” said Heithaus.
The ultimate goal of Shark vs. Ross Edgley—and indeed all of the SHARKFEST programming—is to help shift public perceptions of sharks. “The great Sir David Attenborough said that the problems facing us in terms of conservation is as much a communication issue as a scientific one,” Edgley said. “The only way we can combat that is by educating people.”
Shark populations have declined sharply by 70 percent or more over the last 50 years. “It’s really critical that we protect and restore these populations,” Heithaus said. Tiger sharks, for instance, eat big grazers like turtles and sea cows, and thus protect the sea grass. (Among other benefits, the sea grass sequesters carbon dioxide.) Sharks are also quite sophisticated in their behavior. “Some have social connections with other sharks, although not to the same extent as dolphins,” said Heithaus. “They’re more than just loners, and they may have personalities. We see some sharks that are more bold, and others that are more shy. There’s a lot more to sharks than we would have thought.”
People who hear about Edgley’s basking shark encounter invariably assume he’d been in danger. However, “We were friends. I’m not on its menu,” Edgley said. “There are so many different species.” He likened it to being chased by a dog. People might assume it was a rottweiler giving chase, when in fact the basking shark is the equivalent of a poodle. “Hopefully what people take away from this is moving from a fear and misunderstanding of sharks to respect and admiration,” Edgley said. “That’ll make the RAF fighter pilot plane worth it.”
And he’s game to take on even more shark challenges in the future. There are a lot more shark species out there, after all, just waiting to go head-to-head with a human ultra-athlete.
Shark vs. Ross Edgley premieres on Sunday, June 30, 2024, on Disney+.
Enlarge/ A Sixgill Hagfish (Eptatretus hexatrema) in False Bay, South Africa.
The humble hagfish is an ugly, gray, eel-like creature best known for its ability to unleash a cloud of sticky slime onto unsuspecting predators, clogging the gills and suffocating said predators. That’s why it’s affectionately known as a “snot snake.” Hagfish also love to burrow into the deep-sea sediment, but scientists have been unable to observe precisely how they do so because the murky sediment obscures the view. Researchers at Chapman University built a special tank with transparent gelatin to overcome this challenge and get a complete picture of the burrowing behavior, according to a new paper published in the Journal of Experimental Biology.
“For a long time we’ve known that hagfish can burrow into soft sediments, but we had no idea how they do it,” said co-author Douglas Fudge, a marine biologist who heads a lab at Chapman devoted to the study of hagfish. “By figuring out how to get hagfish to voluntarily burrow into transparent gelatin, we were able to get the first ever look at this process.”
As previously reported, scientists have been studying hagfish slime for years because it’s such an unusual material. It’s not like mucus, which dries out and hardens over time. Hagfish slime stays slimy, giving it the consistency of half-solidified gelatin. That’s due to long, thread-like fibers in the slime, in addition to the proteins and sugars that make up mucin, the other major component. Those fibers coil up into “skeins” that resemble balls of yarn. When the hagfish lets loose with a shot of slime, the skeins uncoil and combine with the salt water, blowing up more than 10,000 times its original size.
From a materials standpoint, hagfish slime is fascinating stuff that might one day prove useful for biomedical devices, or weaving light-but-strong fabrics for natural Lycra or bulletproof vests, or lubricating industrial drills that tend to clog in deep soil and sediment. In 2016, a group of Swiss researchers studied the unusual fluid properties of hagfish slime, specifically focusing on how those properties provided two distinct advantages: helping the animal defend itself from predators and tying itself in knots to escape from its own slime.
Hagfish slime is a non-Newtonian fluid and is unusual in that it is both shear-thickening and shear-thinning in nature. Most hagfish predators employ suction feeding, which creates a unidirectional shear-thickening flow, the better to clog the gills and suffocate said predators. But if the hagfish needs to get out of its own slime, its body movements create a shear-thinning flow, collapsing the slimy network of cells that makes up the slime.
Fudge has been studying the hagfish and the properties of its slime for years. For instance, way back in 2012, when he was at the University of Guelph, Fudge’s lab successfully harvested hagfish slime, dissolved it in liquid, and then “spun” it into a strong-yet-stretchy thread, much like spinning silk. It’s possible such threads could replace the petroleum-based fibers currently used in safety helmets or Kevlar vests, among other potential applications. And in 2021, his team found that the slime produced by larger hagfish contains much larger cells than slime produced by smaller hagfish—an unusual example of cell size scaling with body size in nature.
A sedimentary solution
This time around, Fudge’s team has turned their attention to hagfish burrowing. In addition to shedding light on hagfish reproductive behavior, the research could also have broader ecological implications. According to the authors, the burrowing is an important factor in sediment turnover, while the burrow ventilation changes the chemistry of the sediment such that it could contain more oxygen. This in turn would alter which organisms are likely to thrive in that sediment. Understanding the burrowing mechanisms could also aid in the design of soft burrowing robots.
Enlarge/ Burrowing sequences for a hagfish digging through transparent gelatin.
D.S. Fudge et al., 2024
But first Fudge’s team had to figure out how to see through the sediment to observe the burrowing behavior. Other scientists studying different animals have relied on transparent substrates like mineral cryolite or hydrogels made of gelatin, the latter of which has been used successfully to observe the burrowing behavior of polychaete worms. Fudge et al. opted for gelatin as a sediment replacement housed in three custom transparent acrylic chambers. Then they filmed the gelatin-burrowing behavior of 25 randomly selected hagfish.
This enabled Fudge et al. to identify two distinct phases of movement that the hagfish used to create their u-shaped burrows. First there is the “thrash” stage, in which the hagfish swims vigorously while moving its head from side to side. This not only serves to propel the hagfish forward, but also helps chop up the gelatin into pieces. This might be how hagfish overcome the challenge of creating an opening in the sediment (or gelatin substrate) through which to move.
Next comes the “wriggle” phase, which seems to be powered by an “internal concertina” common to snakes. It involves the shortening and forceful elongation of the body, as well as exerting lateral forces on the walls to brace and widen the burrow. “A snake using concertina movements will make steady progress through a narrow channel or burrow by alternating waves of elongation and shortening,” the authors wrote, and the loose skin of the hagfish is well suited to such a strategy. The wriggle phase lasts until the burrowing hagfish pops its head out of the substrate. The hagfish took about seven minutes or more on average to complete their burrows.
Naturally there are a few caveats. The walls of the acrylic containers may have affected the burrowing behavior in the lab, or the final shape of the burrows. The authors recommend repeating the experiments using sediments from the natural habitat, implementing X-ray videography of hagfish implanted with radio markers to capture the movements. Body size and substrate type may also influence burrowing behavior. But on the whole, they believe their observations “are an accurate representation of how hagfish are creating and moving within burrows in the wild.”
Whales use complex communication systems we still don’t understand, a trope exploited in sci-fi shows like Apple TV’s Extrapolations. That show featured a humpback whale (voiced by Meryl Streep) discussing Mahler’s symphonies with a human researcher via some AI-powered inter-species translation app developed in 2046.
We’re a long way from that future. But a team of MIT researchers has now analyzed a database of Caribbean sperm whales’ calls and has found there really is a contextual and combinatorial structure in there. But does it mean whales have a human-like language and we can just wait until Chat GPT 8.0 to figure out how to translate from English to Sperm-Whaleish? Not really.
One-page dictionary
“Sperm whales communicate using clicks. These clicks occur in short packets we call codas that typically last less than two seconds, containing three to 40 clicks,” said Pratyusha Sharma, a researcher at the MIT Computer Science and Artificial Intelligence Laboratory and the lead author of the study. Her team argues that codas are analogues of words in human language and are further organized in coda sequences that are analogues of sentences. “Sperm whales are not born with this communication system; it’s acquired and changes over the course of time,” Sharma said.
Seemingly, sperm whales have a lot to communicate about. Earlier observational studies revealed that they live a fairly complex social life revolving around family units forming larger structures called clans. They also have advanced hunting strategies and do group decision-making, seeking consensus on where to go and what to do.
Despite this complexity in behavior and relationships, their vocabulary seemed surprisingly sparse.
Sharma’s team sourced a record of codas from the dataset of the Dominica Sperm Whale Project, a long-term study on sperm whales that recorded and annotated 8,719 individual codas made by EC-1, a sperm whale clan living in East Caribbean waters. Those 8,719 recorded codas, according to earlier research on this database, were really just 21 coda types that the whales were using over and over.
A set of 21 words didn’t look like much of a language. “But this [number] is exactly what we found was not true,” Sharma said.
Fine-grained changes
“People doing those earlier studies were looking at the calls in isolation… They were annotating these calls, taking them out of context, shuffling them up, and then tried to figure out what kind of patterns were recurring,” Sharma explained. Her team, by contrast, analyzed the same calls in their full context, basically looking at entire exchanges rather than at separate codas. “One of the things we saw was fine-grained changes in the codas that other whales participating in the exchange were noticing and reacting to. If you looked at all these calls out of context, all these fine-grained changes would be lost; they would be considered noise,” Sharma said.
The first of those newly recognized fine-grained changes was termed “rubato,” borrowed from music, where it means introducing slight variations in the tempo of a piece. Communicating sperm whales could stretch or shrink a coda while keeping the same rhythm (where rhythm describes the spacing between the clicks in a coda).
The second feature the researchers discovered was ornamentation. “An ornament is an extra click added at the end of the coda. And when you have this extra click, it marks a critical point, and the call changes. It either happens toward the beginning or at the end of the call,” said Sharma.
The whales could individually manipulate rubato and ornamentation, as well as previously identified rhythm and tempo features. By combining this variation, they can produce a very large variety of codas. “The whales produce way more combinations of these features than 21—the information-carrying capacity of this system is a lot more capable than that,” Sharma said.
Her team identified 18 types of rhythm, three variants of rubato, five types of tempo, and an ability to add an ornament or not in the sperm whale’s communication system. That adds up to 540 possible codas, of which there are roughly 150 these whales frequently used in real life. Not only were sperm whales’ calls built with distinctive units at a coda level (meaning they were combinatorial), but they were compositional in that a call contained multiple codas.
But does that get us any closer to decoding the whale’s language?
“The combinatoriality at the word level and compositionality at the sentence level in human languages is something that looks very similar to what we found,” Sharma said. But the team didn’t determine whether meaning was being conveyed, she added. And without evidence of meaning, we might be barking up the wrong tree entirely.
