Even though many parts of the northeastern United States have seen surges of summer temperatures, it’s technically still spring in the Northern Hemisphere, which means many animals are having babies.
That’s true also at Yellowstone National Park, which is home to everything from moose and black bears to river otters and gophers. In a recent social media post, the popular park highlighted some particularly adorable young’uns, including a young bison, black bear, yellow-bellied marmot, three b
Even though many parts of the northeastern United States have seen surges of summer temperatures, it’s technically still spring in the Northern Hemisphere, which means many animals are having babies.
That’s true also at Yellowstone National Park, which is home to everything from moose and black bears to river otters and gophers. In a recent social media post, the popular park highlighted some particularly adorable young’uns, including a young bison, black bear, yellow-bellied marmot, three bighorn sheep, an elk, and two pronghorns.
All of Yellowstone National park is considered bear country. Image: NPS.
“As cute and fuzzy as they are, remember to give wildlife room and use a zoom,” the park wrote. “Always maintain a distance of at least 100 yards (91 m) away from bears, wolves, and cougars and at least 25 yards (23 m) away from all other animals, including bison and elk. Get a closer look by using binoculars, a spotting scope, or zoom lens.”
As always, listen to Yellowstone park rangers on this for your own well-being. However, if you run into a baby animal on its own in a more suburban or urban setting, it may be best to get involved. For example, acting quickly is best with baby opossums (Didelphis virginiana) and baby squirrels.
Yellow-bellied marmots are one of Yellowstone’s largest rodents. Image: NPS.
Opossums are pretty lousy mothers. It’s typically not possible to reunite baby opossums with their mothers, because when they fall off her back, she usually continues on her way without them. If you find one or more opossum babies by themselves, call a wildlife hospital or a licensed wildlife rehabber.
As for baby squirrels, they sometimes fall out of their nests. If you find one and 12 hours later the mother hasn’t come to get it yet, pick it up and call a wildlife rehabilitator, New England Wildlife Center Program Founder Greg Mertz has previously told Popular Science. A video by the same wildlife center has a hilariously wacky but serious tip: try to get a baby squirrel back to its mother by elevating it in a basket (to keep predators away) and playing baby squirrel noises from YouTube (to attract the squirrel mom).
Concrete is everywhere, and that’s a problem. Manufacturing the essential material accounts for around eight percent of annual global carbon dioxide emissions, making it one of the single biggest contributors to the climate crisis. Researchers are investigating all types of creative solutions to the issue, often by replacing ingredients with more eco-friendly alternatives.
Recent propositions include adding coffee grounds, bacteria, and even recycled diapers into the mix.But engineers at Purd
Concrete is everywhere, and that’s a problem. Manufacturing the essential material accounts for around eight percent of annual global carbon dioxide emissions, making it one of the single biggest contributors to the climate crisis. Researchers are investigating all types of creative solutions to the issue, often by replacing ingredients with more eco-friendly alternatives.
Recent propositions include adding coffee grounds, bacteria, and even recycled diapers into the mix.But engineers at Purdue University in Indiana think the answer can already be found in the natural world. According to a study recently published in the journal Chemistry of Materials, one solution may be swapping out the cement for shellfish.
“Oysters generate a natural cement. They use this material for attaching to each other when building reef structures,” chemist and study co-author Jonathan Wilker explained in a recent university profile.
Wilker has spent years examining the biological properties of oyster cement in hopes of recreating the sturdy adhesive for other applications. They have since learned that the bivalves bind together by producing the inorganic compound calcium carbonate—basically chalk. While calcium carbonate isn’t usually adhesive by itself, oysters also produce a small amount of stickier organic materials like phosphorylated proteins. This allows the shellfish to fuse together, even when saturated in water.
After breaking down the chemical composition of oyster cement, Wilker’s team recreated it in a laboratory. They then collected a bunch of limestone bathroom tiles, since their calcium carbonate is virtually identical to oyster shells. From there, they glued stacks of tiles together using their artificial, biomimetic cement. In nearly every stress test, the tiles broke before the bond itself.
Confident in their faux-oyster cement’s abilities, Wilker and colleagues finally tried combining a polymer from their creation into commercially available concrete mix. In lab tests, their oyster-inspired concrete was 10 times stronger while doubling its compressive strength. On top of all that, it also took less time to cure.
Wilker’s team plans to continue testing their patent-pending recipe. He notes that it’s not simply stronger. It’s even more eco-friendly when compared to most adhesives on the market.
“Most of the adhesives that you see at the hardware store are made of organic compounds, derived from petroleum,” he said. “There is so much more that we can learn from nature.
Everyone who has ever owned a hamster knows the sound: the small, relentless squeak of the exercise wheel, usually starting around two in the morning.
As you watch your cute furball running toward no destination whatsoever, you might wonder: What’s going on here? Is little Hammy acting out of restlessness or boredom?
For decades, scientists assumed it was exactly that: a neurosis, an artifact of captivity, the hamster equivalent of doing push-ups in prison.
But in 2014, researcher Joh
Everyone who has ever owned a hamster knows the sound: the small, relentless squeak of the exercise wheel, usually starting around two in the morning.
As you watch your cute furball running toward no destination whatsoever, you might wonder: What’s going on here? Is little Hammy acting out of restlessness or boredom?
For decades, scientists assumed it was exactly that: a neurosis, an artifact of captivity, the hamster equivalent of doing push-ups in prison.
But in 2014, researcher Johanna Meijer conducted a study that suggested a less depressing scenario. When wild mice came across a wheel in their natural habitat, they got on the wheel and ran—sometimes for up to 18 minutes at a stretch.
So if it’s not boredom or neurosis (wild mice surely have plenty of more important tasks than wheel running), what is it?
Dr. Theodore Garland Jr., a professor of biology at UC Riverside, has spent more than 30 years trying to figure that out.
“There’s still a lot of controversy about what, exactly, wheel running means to an organism,” Garland says. “What is it? What is the organism trying to do?”
Why wild mice run on wheels just like your hamster
In Meijer’s 2014 study, published in Proceedings of the Royal Society B, she and her colleagues placed exercise wheels in two different locations: a green urban area and a dune area not accessible to the public. For more than three years, they recorded wildlife activity at both locations.
They found that wild mice closely mirrored the behavior of their cage-dwelling counterparts. At both locations, the mice frequently ran on the wheels—often for lengths of time equal to the “workout” durations of captive mice.
Although food was initially used to attract animals to the wheel, the researchers found that wheel running continued even after the food was removed. This suggests that the animals not only ran voluntarily on the wheel, but did so without any external reward.
The wheels attracted more than just mice, too. Shrews, frogs, and even slugs were recorded using the equipment (a few snails were excluded from the study due to “haphazard” movements on the wheel). But wild mice used the wheel far more than another animal, accounting for 88 percent of all wheel runners.
Hamsters aren’t the only creatures that like running on wheels. Video: Wild Animals Caught On Hamster Wheel, Live Science
So, why do rodents specifically enjoy a run to nowhere? Are slugs simply less committed to their cardio?
According to Garland, rodents are simply built for it—bigger home ranges, faster metabolisms, and the aerobic capacity to sustain speed over distance.
“A toad isn’t going to be running 10 kilometers in a day,” Garland says. “Whereas a chipmunk could be.”
Dopamine keeps mice and hamsters coming back for more
But that’s only part of the story. The more interesting question is why any animal would choose to do it at all.
According to Garland, the drive to run on wheels among free-ranging animals is not fully understood, but the behavior is likely tied to the reward centers of the brain.
“Dopamine is viewed as the final common denominator,” Garland says, referencing the neurotransmitter that delivers a sense of pleasure to the brain’s reward system. Similar to a human working out at the gym, mice get a dopamine boost every time they run on their trusty wheel.
In Garland’s own lab, mice placed in larger, rat-sized wheels will sometimes slow down mid-run and rather than jumping off as the wheel keeps spinning, complete a full 360, and keep going. It serves no obvious purpose. It looks, for all the world, like a bit of acrobatics, as if the little mouse is creating its very own roller coaster.
“I’m hesitant to use the ‘F-word’ about lower vertebrates,” he says, “but it’s hard to ignore the idea that they’re getting some sort of pleasure or enjoyment out of it.”
The reward system may explain the drive, but Garland sees something even more elemental at work—something similar to the “zoomies” dogs and other young animals get.
A baby horse, Garland notes, will sometimes just tear around a field for no apparent reason—solo, unprompted, burning energy for the sheer joy of it. “We used to call it nip-norting,” he says, “just going crazy, even without another individual to egg it on.”
Exercising at a young age leads to lifelong habits, even for hamsters
Rodents’ love of running on wheels might even have implications for humans. Some of Garland’s work suggests that, when introduced at a young age, wheel running can become a lifelong habit.
In his study, Garland found that mice given access to a running wheel immediately after weaning, at just three weeks old, ran significantly more as adults.
“It’s got to be something up here,” Garland says, indicating the brain. “Their reward system has been permanently tweaked.”
Whatever it is keeping these little guys running, an early start seems to predict an ongoing practice. The implications, Garland believes, extend well beyond mice. For instance, cutting physical education from school curricula, he says, could be “a huge public policy disaster,” leading to adults who aren’t used to exercising.
“If you’re a kid who never gets to play basketball or tennis,” he says, “and then you get to college, and your friends are playing pickup games, it’s probably not even on your radar to do that kind of thing.”
Of course, none of this is on your hamster’s radar at all. They’re just galloping away, keeping you awake with the endless rotation of their squeaky wheel. But all that running can also lead to some good: Recently, a resourceful young YouTuber rigged his brother’s hamster wheel to charge his phone.
But no need to worry—the clever teen isn’t exploiting the toil of a joyless captive. Hammy, it seems, is just doing what comes naturally.
In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.
The babies are growing up. Since hatching in early April, Jackie and Shadow’s eaglets have sprouted new feathers, developed keen vision, and now, they’re practicing some vital grownup skills. Sandy and Luna can be seen engaged in lively wing-flapping sessions. While it might look a little awkward, the movement helps the chicks develop their pectoral muscles, an essential step in learning to fly.
“It [also] helps them learn the ‘wingspan’ of their own bodies so they don’t hit the nest walls or
The babies are growing up. Since hatching in early April, Jackie and Shadow’s eaglets have sprouted new feathers, developed keen vision, and now, they’re practicing some vital grownup skills. Sandy and Luna can be seen engaged in lively wing-flapping sessions. While it might look a little awkward, the movement helps the chicks develop their pectoral muscles, an essential step in learning to fly.
“It [also] helps them learn the ‘wingspan’ of their own bodies so they don’t hit the nest walls or their siblings,” Friends of Big Bear Valley (FOBVV), the non-profit group that maintains the eagles’ livestream, explains. But don’t expect them to fly away anytime soon. The chicks are only about six weeks old and fledging won’t happen until 10-14 weeks of age. Last year, Sunny and Gizmo each fledged around 13 weeks.
Viewers might also notice the pair stomping around their nest. Again, the eaglets aren’t exactly graceful, but this behavior is important. Bald eagles are raptors, or birds of prey, so learning how to hunt is essential to long-term survival. “This is an instinctual behavior to ‘pin’ prey down,” FOBBV explains. “Because they are top-heavy at this age, stomping helps them find their center of gravity as their legs grow longer and stronger.” Although, yes, they do occasionally stomp on each other’s toes.
It’s been another roller coaster nesting season for Jackie and Shadow, a pair of internet-famous bald eagle parents living in San Bernardino National Forest in Southern California. After two of their eggs were destroyed by ravens in January, Jackie and Shadow laid two new eggs that have successfully hatched.
Chick 1 hatched on April 4 at 9:33 p.m. PDT, while Chick 2 followed on April 5 at 8:30 a.m. Their large nest in Big Bear Valley east of Los Angeles is livestreamed 24 hours a day by nonprofit Friends of Big Bear Valley (FOBBV) and has captivated millions.
On May 1, FOBBV announced the chicks’ names: Sandy and Luna.
Before leaving the nest, the chicks face threats from other birds of prey, including hawks, ravens, other eagles, and owls. Inclement weather can also present challenges for the chicks. In 2025, a March snowstorm resulted in the death of one of Jackie and Shadow’s three chicks.
During fledging, only 70 percent of eaglets survive. One of the greatest threats is from cars that can injure or kill the birds while they scavenge for food on roadkill.
Who are Jackie and Shadow?
The pair first got together in 2018 and successfully raised chicks in 2019 and 2022. However, their eggs failed to hatch in 2023 and 2024. Only 50 percent of eagle eggs successfully hatch, so this pair has already beaten the odds.
What happened to Jackie and Shadow’s 2025 eaglets?
In 2025, Jackie laid three eggs that all hatched in early March. On March 13, a strong snowstorm dumped up to two feet of snow and battered the nest with strong winds. Only two of the chicks were visible on the live cam when the storm passed by the next morning. FOBBV later confirmed the passing of one of the chicks. The two surviving chicks were later named Sunny and Gizmo after 54,000 names were submitted by fans.
What happens after chicks fledge?
Young eagles usually fledge–or leave the nest and fly–when they can flatten their wings and have feathers capable of flight. This typically occurs when the birds hit 10 to 14 weeks of age. Males also tend to take their first flight a little sooner than females.
According to FOBBV, fledglings from Southern California have been spotted as far south as Baja California, as far north as British Columbia, and as far east as Yellowstone National Park.
About 70 percent of bald eagles survive the fledgling stage. FOBBV does not tag their eagles, so it’s not possible to follow the chicks’ journeys after they flee the nest.
Can I help Jackie and Shadow?
Yes. Environmental groups are currently fundraising $10 million to protect Jackie and Shadow’s foraging area from development. Learn more at SaveMoonCamp.org.
Researchers studying copulation in mayflies pulled off a stunt worthy of the naughtiest ancient Greek myths. Just like Hephaestus used an unbreakable net to trap his wife Aphrodite and her lover Ares in the middle of their adulterous act, a team of scientists in Germany deployed a long-handled net to catch mating insects, and then used freezing spray to preserve the moment for study.
And that’s not even the strangest part of the study titled, “When mayflies have an erection: functional morph
Researchers studying copulation in mayflies pulled off a stunt worthy of the naughtiest ancient Greek myths. Just like Hephaestus used an unbreakable net to trap his wife Aphrodite and her lover Ares in the middle of their adulterous act, a team of scientists in Germany deployed a long-handled net to catch mating insects, and then used freezing spray to preserve the moment for study.
Mayflies are a group of strange winged insects with dramatic life cycles. They live as larvae in freshwater for most of their lives. When they finally become adults, they stop eating (their gut closes off and turns into a balloon) and they exist to fulfill a single mission—sex.
Before the Insect Systematics and Diversity study, researchers knew very little about mayfly mating. It’s easy to see why, since the act is fast and it takes place mid-flight, in the air. The team was clearly undeterred in their quest to understand the intimate affairs of much smaller beings.
The team collected Ecdyonurus venosus mayflies in Germany’s Black Forest. There, they used a long-handled net to catch copulating pairs. Unsurprisingly, most of the captured duos split up right away. Those that didn’t, however, would experience the literal meaning of Dolly Parton’s hit song “I Will Always Love You.” The team then shock-froze them with freezing spray and preserved them in ethanol.
Benedict Stocker shock-freezing a copulating pair of mayflies in a net. Image: A. Staniczek / SMNS.
The researchers then used synchrotron X-ray microtomography (µCT) at the synchrotron particle accelerator of the Karlsruhe Institute of Technology, producing images for a digital 3D model.
“The aim of the present work is to clarify the function of genital interactions during copulation in the mayfly genus Ecdyonurus,” the team wrote in the study, “and to unravel the mechanisms that lead to the change in the penis configuration during mating.”
Yes, you read that right. Their penis changes—and the males sort of have two of them.
A tale of two penises
Mayfly sex is of a shockingly acrobatic dynamic. Males swarm over bodies of water to seduce females. When a female introduces herself into the fray, the copulation occurs immediately and in midair. The male attaches onto the female from below, using forelegs to hold onto the bases of her wings, and then bends his abdomen up and over. He also uses specialized genital forceps called claspers to secure his grip. Mating can now take place.
Females have a copulatory pouch that opens towards the back. Males have two separate penis lobes that have spines in between them and claspers on both sides of the “paired penis.” Similarly to the claspers, the spines keep the paired penis in place during mating.
Male (left) and female (right) of the mayfly species Ecdyonurus venosus, body length approx. 1.2 cm. Image: Copyright: A. Staniczek / SMNS.
“µCT scans show that the penis changes shape during mating powerful muscles cause[ing] a deformation of the penis shaft, making the penis lobes fold over. At the same time, the penial spines extend and prick into the thin membrane of the female’s copulatory pouch,” per a statement. “This stretches the pouch so that it can receive large amounts of sperm, which are stored in a folded membrane at the front of the copulatory pouch.”
As if mayfly mating wasn’t complicated enough, other males frequently attempt to steal the female, so male mayflies’ sturdy attachment is doubly useful. Once the mating is done, however, the couple doesn’t get to celebrate their achievement for long.
Researchers don’t know if they mate multiple times, but not much time passes before the males die of exhaustion from the swarming flight. The females lay the fertilized eggs in upstream water—and then also die.
Cats are famously obsessed with catnip, but a recent social media post from the Bronx Zoo in New York City highlights that it’s not just bossy domestic felines that take an interest in the plant.
In the zoo’s video, a three-year-old female sand cat (Felis margarita) plays with a catnip-filled ball. Sand cats are the sole only species that live in the true desert. They can withstand both exceptional heat and cold, from 122 degrees Fahrenheit (50 degrees Celsius) to -13 degrees Fahrenheit (-25
Cats are famously obsessed with catnip, but a recent social media post from the Bronx Zoo in New York City highlights that it’s not just bossy domestic felines that take an interest in the plant.
In the zoo’s video, a three-year-old female sand cat (Felis margarita) plays with a catnip-filled ball. Sand cats are the sole only species that live in the true desert. They can withstand both exceptional heat and cold, from 122 degrees Fahrenheit (50 degrees Celsius) to -13 degrees Fahrenheit (-25 degrees Celsius). They are found across northern Africa as well as southwest and central Asia.
“The keepers added catnip to this ball to give the sand cats a novel item to stimulate them physically and mentally. Cats respond to a chemical in catnip called nepetalactone,” according to the post. “Its primary function is to repel insects from the plant. Many cats, though not all, are highly attracted to it, and it is safe and non-toxic for them to enjoy.”
Catnip is part of the mint family. According to Jessica Moody, curator of primates and small mammals at the Wildlife Conservation Society (WCS), not all felid species have the same sensitivity to the plant. Moody tells Popular Science that sex and age also impact the response on an individual level. Bronx Zoo (part of the WCS) animal keepers frequently employ catnip, officially called Nepeta cataria, as well as other scents to incite natural behaviors such as investigation and play.
It’s clearly working with this particular feline, whose species the IUCN Red List categorizes as a species of least concern. However, “it is difficult given their low population density and harsh environment to track true wild populations,” Moody explains. “Primary threats to the survival of sand cats in the wild include habitat loss and a decline in prey caused by human disturbances like livestock grazing.”
While swimmers and boaters don’t have to fear sharks or giant squid in the Great Lakes watershed, invasive fish the size of large dogs lurk in the freshwater. Invasive carp have wreaked havoc on the ecosystem for over a century, but officials have hit a milestone worth celebrating in the fight against these mega fish.
In the past 15 years, wildlife officials have removed 50 million pounds of invasive carp from the Illinois River. That’s equivalent to roughly 5,000 elephants. The removal is p
While swimmers and boaters don’t have to fear sharks or giant squid in the Great Lakes watershed, invasive fish the size of large dogs lurk in the freshwater. Invasive carp have wreaked havoc on the ecosystem for over a century, but officials have hit a milestone worth celebrating in the fight against these mega fish.
In the past 15 years, wildlife officials have removed 50 million pounds of invasive carp from the Illinois River. That’s equivalent to roughly 5,000 elephants. The removal is part of a broader and coordinated effort to protect the rivers and lakes from this non native species.
Why are carp a problem?
Currently, four species of invasive carp cause harm in the Great Lakes and beyond—bighead carp (Hypophthalmichthys nobilis), silver carp (Hypophthalmichthys molitrix), black carp (Mylopharyngodon piceus), and grass carp (Ctenopharyngodon idella).
According to the Great Lakes Fishery Commission, all four species were imported to North America to help with pest control in aquaculture facilities in the 1970s. The carp escaped confinement in only 10 years, and have spread to the Mississippi River basin and other large rivers, including the Missouri and Illinois.
Each of the four invasive carp species can weigh more than 100 pounds and grow to four feet from tip to tail. Bighead carp and silver carp generally feed on the tiny plankton in the water, while grass carp eats rooted plants in shallow water, and black carp feed primarily on mollusks and snails.
“They consume so much food and can exist in such great numbers that they can really reduce the amount of [resources] for resident species of fish,” Peter Alsip, an ecologist with the NOAA Great Lakes Environmental Research Lab told Popular Science in 2024. “They can have indirect effects on the whole ecosystem because [silver carp] are consuming phytoplankton and zooplankton, which are essentially the base of the food web.”
Once inside a watershed, they can reproduce rapidly and compete with native fish species for resources. In areas where invasive carp are abundant, they have harmed other fish species and interfered with commercial and recreational fishing, according to the United States Fish & Wildlife Service (USFWS). They can also pose a danger to humans, as the giant fish can jump out of the lake and hit unsuspecting boaters.
What is being done to stop them?
Carp eradication measures have been active for over 100 years. These efforts include targeted mass removal efforts, developing barriers to block or impede their movement, and ongoing monitoring.
Cap being culled in the Illinois River. Image: Illinois Department of Natural Resources.
The 50 million pounds of fish removed from the Illinois River were part of a program focusing on the northern part of the river about 50 miles from Lake Michigan. The removal project is designed to suppress the mostly adult populations of carp living in the area, by limiting their ability to reproduce and reduce their migration upstream towards the Electric Dispersal Barrier System. Located about 37 miles from Lake Michigan, this electric barrier is designed to deter their movement through the Chicago area. It is one of the main tools wildlife officials are using to keep them from further entering the Great Lakes through the Illinois River. Another program in the Illinois River offers fish harvest incentives to commercial fishers in the river’s lower 240 miles.
“The more invasive carp we remove, the more we reduce their harmful impacts and the risk of them reaching Lake Michigan,” the USFWS wrote on Facebook. “Thanks to these and other efforts to monitor our waters and prevent the spread of invasive carp, Illinois and more than two dozen partners are safeguarding some of our most prized native fisheries, and the Great Lakes regional economy.”
Sunburn and mosquito bites go together in the summer like a hot dog and ketchup. To keep from becoming a mosquito buffet, most of us turn to bug sprays with DEET. An acronym built from its scientific identification (diethyltoluamide), DEET was developed for the United States Army in 1946 and entered civilian use in 1957. It is generally considered safe when used as directed.
However, mosquitoes can learn to associate the repellant with food. They may even become attracted to it. The finding
Sunburn and mosquito bites go together in the summer like a hot dog and ketchup. To keep from becoming a mosquito buffet, most of us turn to bug sprays with DEET. An acronym built from its scientific identification (diethyltoluamide), DEET was developed for the United States Army in 1946 and entered civilian use in 1957. It is generally considered safe when used as directed.
However, mosquitoes can learn to associate the repellant with food. They may even become attracted to it. The findings are detailed in a study published today in the Journal of Experimental Biology.
“If someone applies DEET and the concentration fades over time, but a mosquito still manages to feed, the insect may begin associating that smell with a reward,” Clément Vinauger, a study co-author and biochemist at Virginia Tech, said in a statement. “That’s a possibility we should take seriously when we think about how repellents are used in the real world.”
Ace processors
Like it or not, Earth’s over 3,500 known mosquito species are pretty smart and an evolutionary wonder. They use sensory information to find hosts and can adapt to changing environments.
“Mosquitoes are remarkable at processing information about their environment,” Vinauger said. “What we are trying to understand is not only how they detect us, but how their brains interpret those cues and turn them into behavior.”
A DEET-covered dinner bell?
In this new study, the team focused on the yellow fever mosquito (Aedes aegypti). This species spreads several diseases to tens of millions of people each year, including dengue fever, Zika, yellow fever, and chikungunya.
The mosquitoes were restrained behind a piece of fabric mesh. They then offered the mosquitoes a bag of warm blood (yum) that was just out of the insects’ reach to see how enthusiastically the insects stabbed at it with their proboscises. As expected, the mosquitoes were interested in the blood, particularly when the team rewarded them by lowering the bag within reach. Things changed a bit once DEET entered the experiment. When the team offered the insects blood when surrounded by the scent of DEET, they initially stayed away from the potential feast.
A female yellow fever mosquito (Aedes aegypti), feeding on a bag of warm blood. Image: Romina Barrozo.
To see if they could be trained to associate that smell with the dinner bell, the team fed the mosquitoes warm blood for 20 seconds, squirting the scent of DEET into the enclosure in the final 10 seconds of dining. They repeated the procedure three more times before noting how the mosquitoes responded to only the scent of DEET. In this trial, over 60 percent of mosquitoes tried to bite when they smelled DEET.
To examine further, the mosquitoes were given a choice between two human hands. The hand belonged to study co-author Ayelén Nally of the University of Buenos Aires. One of Nally’s hands was coated with DEET at normal concentrations and the other was bare. The untrained mosquitoes avoided the DEET-treated hand, while the trained mosquitoes were drawn to it.
Interestingly, the mosquitoes could form that same association when sugar, instead of blood, was used as the reward.
According to the team, they are seeing how the mosquito’s brain can rewrite its response based on their experiences. What they have learned matters just as much as what a chemical like DEET does.
“If mosquitoes are repeatedly exposed to DEET, it becomes less effective as a repellent,” study co-author Claudio Lazzari from University of Tours in France added.
Keep the bug spray
Importantly, this does not mean you should stop using DEET completely. It is still one of the most effective ways to keep the dangerous insects away, particularly where mosquito-borne disease is common.
“If you’re in tropical regions where disease risk is real, you should use it,” Vinauger said. “Instead of applying a lot at once, you may want to reapply regularly so it’s always active and providing continuous protection.”
Treated clothing may also be a challenge since DEET concentrations in fabric decline over time. Additional study to understand their behavior is crucial for public health as mosquito-borne illnesses increase due to climate change.
“We need to understand how mosquitoes keep outsmarting our control strategies,” Vinauger concluded. “And that takes understanding how they work—at the molecular level, the neural level, the behavioral level.”
Routine checkups for humans are usually straightforward. The doctor tells you what to do, and unless you’re a squirming baby or terrified of needles, you pretty much follow instructions.
But what happens when the patient is a giant yellow-orange eel with sharp teeth? Things get a bit slippery. At the New England Aquarium, experts need to follow a complicated process in order to get Thomas, a green moray eel (Gymnothorax funebris), ready for his yearly checkup.
The first step consists of
Routine checkups for humans are usually straightforward. The doctor tells you what to do, and unless you’re a squirming baby or terrified of needles, you pretty much follow instructions.
But what happens when the patient is a giant yellow-orange eel with sharp teeth? Things get a bit slippery. At the New England Aquarium, experts need to follow a complicated process in order to get Thomas, a green moray eel (Gymnothorax funebris), ready for his yearly checkup.
The first step consists of retrieving Thomas from the aquarium’s giant ocean tank. Divers get him into a plastic barrel.Thomas and the barrel are then submerged into a different water tank with powdered anesthetic water, Melissa Joblon, New England Aquarium’s director of animal health, tells Popular Science.
“We have to be really cautious to make sure that he’s fully anesthetized before we handle him because they can be dangerous,” she adds, “and they’re very slippery and can kind of slither away if we’re not really careful.”
Once Thomas is essentially knocked out, the team lifts him from his sedation bin and onto a rack. They then flush water—with more of the anesthesia agent—which allows him to continue breathing.
The medical exam is preventative care, meaning the team is on the lookout for any health issues to catch them before they become serious. The session includes a physical exam, bloodwork, a full ultrasound, and an electrocardiogram. The team is essentially investigating the eel’s outsides and insides.
“We do full routine annual exams on the majority of the animals that live at the aquarium, similar to bringing your cat or dog to a vet once a year,” Joblon explains.
Thomas is probably 18 to 21 years old, but he was a juvenile when the New England Aquarium took him in. A pet owner donated him after wisely deciding that they couldn’t care for the eel anymore—Thomas was becoming too big. Green moray eels are, after all, among the largest morays—they can be eight feet long.
Small as a grain of rice, polka-dotted, and everything nice. These are some of the ingredients that come together to make Thecacera sesama, a newly identified species of sea slug, or nudibranch, found swimming in Taiwan.
“Taiwanese divers call it ‘sesame’ in Chinese and it is also small like a sesame seed, hence the name,” researchers explain in a statement. Indeed, T. sesama is less than 0.12 inches long. The tiny bugger is also translucent and speckled black and yellow, and Ho-Yeung Chan “a
Small as a grain of rice, polka-dotted, and everything nice. These are some of the ingredients that come together to make Thecacera sesama, a newly identified species of sea slug, or nudibranch, found swimming in Taiwan.
“Taiwanese divers call it ‘sesame’ in Chinese and it is also small like a sesame seed, hence the name,” researchers explain in a statement. Indeed, T. sesama is less than 0.12 inches long. The tiny bugger is also translucent and speckled black and yellow, and Ho-Yeung Chan “accidentally discovered” it while diving in 2019.
A sketch of Thecacera sesama showing its appearance and morphological features. Image: Chen-Lu Lee.
Chan is a researcher at the National Taiwan Ocean University’s Institute of Marine Biology and Center of Excellence for the Oceans, but was an undergraduate student when he made the discovery. Chan didn’t realize he’d found a previously unknown species until after he’d spoken with sea slug identification expert Hsini Lin via Facebook. Chan is now lead author of a recently published ZooKeys study officially introducing T. sesama to the world.
The new sea slug seems to enjoy a simple life. It displays just four main actions: feeding, searching, mating, and laying eggs on bryozoans. Also known as moss animals, bryozoans are a group of small aquatic invertebrates. The bryozoan that hosts T. sesama might also be a previously unknown species.
Living specimens of Thecacera sesama. Image: Ho-Yeung Chan et al., 2026
While you might assume that the most difficult aspect of researching T. sesama is its miniscule size, the hardest part of the study for the team was the explosive weather of Taiwan’s Keelung coast. The island as a whole often has summer typhoons and large waves in the winter monsoon season, during which the sea is frequently colder than 60.8 degrees Fahrenheit.
With these challenging conditions, researchers can only dive to investigate sea slugs for around a third of the year. The narrow window means that spotting the sesame-sized slugs is completely a toss-up.
“Nudibranchs are one of the key players in the marine food web,” the team explained. “They are extremely colourful and can be spotted on coral reef ecosystems. However, many nudibranchs are very small in size and are extremely difficult to spot underwater with the naked eye.”
Chan and colleagues believe that Taiwan’s marine environment is probably home to many other unknown tiny species. It remains to be seen what new strange creature will emerge from the island’s turbulent waters.
Psilocybin is the psychoactive compound that puts the “magic” in magic mushrooms. Ingest enough of a fungus like Psilocybe cubensis, and users are liable to experience sensory hallucinations, euphoria, and even altered perceptions of time. Mounting research also suggests that smaller, microdosed amounts may offer promising alternative therapeutic options for treating PTSD, depression, and even alcoholism.
But what happens when you give fish the same psychoactive ingredient? It may sound like
Psilocybin is the psychoactive compound that puts the “magic” in magic mushrooms. Ingest enough of a fungus like Psilocybe cubensis, and users are liable to experience sensory hallucinations, euphoria, and even altered perceptions of time. Mounting research also suggests that smaller, microdosed amounts may offer promising alternative therapeutic options for treating PTSD, depression, and even alcoholism.
But what happens when you give fish the same psychoactive ingredient? It may sound like an odd, even pointless experiment, but biological neuroscientists think the results could inform future medical and psychiatric treatments. Their evidence laid out in a study published today in the journal Frontiers in Behavioral Neuroscience suggests small levels of psilocybin ease anxiety or aggression. Or, at the very least, it calms down a notoriously mean species of fish.
The mean fish in question is the mangrove rivulus (Kryptolebias marmoratus). It is a remarkable creature found along the coast of Florida all the way to Brazil.The 1.5 to three inch amphibious fish has evolved to not only thrive in brackish waters, but survive on land for as long as two months. They’re also extremely aggressive and territorial, making them suitable for certain social and behavioral studies. And because the mangrove rivulus self-fertilizes and produces genetically identical embryos, they offer researchers conveniently uniform models.
To test how psilocybin affects the traditionally confrontational fish, a team from Nova Scotia’s Acadia University and the University of British Columbia bred three genetically distinct lines of laboratory rivulus. One group was exposed to the psychoactive compound, another essentially served as a target for their aggression, and a third was employed separately to assess psilocybin absorption and bodily concentration.
Researchers first observed the standard interactions between two fish separated by a mesh barrier in a tank. These frequently include high-energy “swimming bursts” to intimidate each other without making physical contact, as well as less energy intensive, head-on displays of hostility. On the following day, the team placed one of the rivulus into a water tank that included dissolved psilocybin for 20 minutes. Finally, they transported the now-dosed fish back into the tank with its original foe and watched their reunion.
The team’s findings offer the first direct evidence that psilocybin can selectively reduce the escalating aggression in the fish, without dampening their social interactions. Rivulus with psilocybin in their system significantly reduced their tendency to perform swimming bursts, but still participated in easier head-on displays. Basically, the fish calmed down a bit—but they also got very lazy.
“Psilocybin’s calming effect appears to selectively reduce energetically costly, escalated behaviors while lower‑energy social display behaviors remained largely unchanged,” study co-author and biologist Dayna Forsyth said in a statement. “This suggests that this compound can selectively dampen escalated social conflict rather than shutting down behavior altogether.”
That’s great for the mangrove rivulus, but what about humans? While the experiment focused on a single dose of psilocybin under short time constraints, the team’s findings may kickstart further explorations of the psychoactive compound’s uses in therapeutic treatments. In particular, knowing what social behaviors are affected by psilocybin versus the behaviors that remain unchanged can help researchers hone the scope of their future work.
“These are questions that are difficult or impossible to answer directly in humans,” added University of British Columbia biologist and study c-oauthor Suzie Curie.
With another Arctic front heading our way, I find myself thinking about sea otters – specifically, how well suited (literally) they are for winter. Their incredibly thick, waterproof coats must be cozy even on unseasonably chilly days. Sea otters have the densest fur of any animal on earth, which is why they were hunted almost […]
With another Arctic front heading our way, I find myself thinking about sea otters – specifically, how well suited (literally) they are for winter. Their incredibly thick, waterproof coats must be cozy even on unseasonably chilly days. Sea otters have the densest fur of any animal on earth, which is why they were hunted almost […]
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