Daddy longlegs have been spotted devouring live frogs bigger than themselves in the tropical forests of South America, a new study reports. And this behavior might be more common than scientists expected.

"Finding these animals eating [live] frogs was a complete surprise, we didn't expect them to be able to capture them," study co-author Luís Fernando García, a biologist at the University of the Republic in Uruguay, told Live Science.

When arthropods, the group that includes animals like insects, spiders, centipedes and crustaceans, are observed eating vertebrates, it's typically treated as a rare or isolated phenomenon. But Jose Valdez, an ecologist at Martin Luther University Halle-Wittenberg in Germany who was not involved in the new study, has found that this type of predation — mostly on frogs, lizards, bats and birds — is actually quite common.

In reality, arthropod predation on vertebrates is under-documented, Valdez told Live Science in an email. Valdez's research has found it is most commonly spiders eating frogs, since frogs' soft bodies and thin skin make them relatively vulnerable.

Yet harvestmen (order Opiliones), also known as daddy longlegs, are not technically spiders; they are part of the arachnid class alongside spiders, but they are more closely related to scorpions, so observations like this new study are particularly noteworthy, Valdez said.

In the new paper, published April 21 in the journal Ecology and Evolution, the research team compiled 10 reports in South America of harvestmen eating frogs around their body size. The reports come from field observations in Ecuador and Colombia, scientific papers, and one from the citizen science platform iNaturalist, which lets anyone with a camera upload photos of wildlife and plants.

"The availability of good quality cameras on mobile phones has enormously helped in recording such interactions and making them available to specialists, sometimes through citizen science platforms," Olivier Pauwels, a conservation biologist at the Royal Belgian Institute of Natural Sciences who was not involved in the new study, told Live Science in an email.

Previous anecdotal reports of daddy longlegs eating frogs have been unclear about whether the arachnid had killed the frog or scavenged an already dead amphibian.

"What we found is that they are able to capture frogs, because many frogs were still moving" in these observations, García said, suggesting that the arachnids might be actively hunting frogs.

The researchers don't know exactly how harvestmen capture frogs, since the arachnids are rather slow and don't have venom, García said. They may be hunting sleeping or resting frogs, or grabbing them with their strong front limbs, known as pedipalps, which are similar to the forelegs of praying mantises and can grasp prey.

"The most surprising aspect is how these harvestmen are able to subdue their prey" without venom to chemically immobilize animals, Valdez said. "Instead, they must rely entirely on physical restraint," an impressive feat since some frogs were up to 1.29 times the size of the arachnids eating them, the study found.

"We now have a new field to explore: the feeding and behavior of these animals, which is basically unknown," García said. "We think it is opportunistic behavior, they are generalist predators."

New discoveries about arthropods' diets in the tropics, and their interactions with other species, can help scientists understand how to conserve these ecosystems.

"The fate of some species is often linked to others," Pauwels said.

The patient: A 32-year-old woman in Shanghai

The symptoms: The woman went to the hospital with a persistent cough accompanied by occasional bloody phlegm, which she would cough up two to three times per day. She said the coughing began four months prior to her hospital visit. And about a month before the coughing started, she had a fever that lasted several weeks and reached up to 100.8 degrees Fahrenheit (38.3 degrees Celsius).

What happened next: Doctors at the hospital diagnosed the woman with a rare respiratory illness called eosinophilic pneumonia, an infection in which white blood cells accumulate in the lungs and cause inflammation. If left untreated, the infection can damage the lungs, and in some cases, it can be fatal.

The patient's doctors gave her steroids to reduce the inflammation in her lung tissue. However, her cough persisted even after two months of this treatment. A CT scan of her lungs revealed recurring lesions, or tissue injuries, and she was then sent to a different hospital for further examination.

The diagnosis: When doctors at the second hospital reviewed the woman's medical history, they noted that her diet often included raw seafood, and she also reported "a preference for raw frogs and bullfrogs," the physicians wrote in a report describing her case. The team conducted a blood test to see if her blood contained antibodies to any parasites, and they found antibodies for the larvae of Spirometra mansoni, a type of tapeworm.

The larvae, or spargana, of S. mansoni cause a parasitic infection called sparganosis. This infection is most common in eastern Asia, and people often acquire the parasites by eating raw or undercooked snakes or frogs that are infected with the larvae, evidence suggests. After S. mansoni larvae are swallowed, they migrate into various body tissues and organs. In the woman's case, they accumulated in her lungs — a very rare destination for the parasite.

When the patient provided doctors with a frog from her region of Shanghai, they dissected it and found that it was carrying S. mansoni.

Because the woman's symptoms and the results of her CT scans closely resembled signs of eosinophilic pneumonia, the physicians who examined her during her first hospital visit misdiagnosed her, according to the report.

The treatment: Doctors treated the woman with praziquantel tablets, a drug that works against various types of parasitic worms. After the woman had taken the tablets for five days, her coughing subsided.

CT scans performed 20 days after her admission to the second hospital showed that the shadowy areas previously seen in her lungs — a sign of infection or physical trauma — were shrinking. At a follow-up visit one month later, her coughing was completely gone. However, the patient's blood tests showed that she was still producing antibodies against the parasite, hinting that the infection persisted.

Doctors prescribed another five-day course of praziquantel and conducted a follow-up examination five months after that. Traces of antibodies remained in the patient's blood, but only in extremely low quantities. Her white blood cell count was normal, and the doctors determined that no further treatment was required.

What makes the case unique: Sparganosis infections typically appear in tissues located just under the skin, near the surface of the body. They rarely migrate to the internal organs. This is the first case to be documented in Shanghai of sparganosis in the lungs, the case report authors wrote.

Eating raw animal flesh is a long-standing cultural tradition in parts of Asia, and sometimes, small animals may be consumed while they are still alive. Living frogs are occasionally eaten as a folklore remedy for a variety of ailments; an 82-year-old woman in Hangzhou was hospitalized with a parasitic infection after she swallowed eight small, live frogs in an attempt to relieve her chronic back pain.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Archaeologists have discovered the remains of three Maya cities in the Petén jungle of Guatemala.

The cities are about 3 miles (5 kilometers) apart and are arranged like a triangle, Guatemala's Ministry of Culture and Sports reported in a translated statement. The cities were settled sometime during a period that archaeologists call the "middle preclassic," which occurred between roughly 1000 and 400 B.C. They were inhabited until around 1,100 years ago, when many Maya cities in the region collapsed.

The most important of the three cities is a site archaeologists are calling "Los Abuelos," which means "the grandparents." This name comes from two stone sculptures found at the site: one of a man and another of a woman. They are believed to depict ancestors of those who lived at the site, the statement said, noting that this city may have been a ceremonial center for those who lived in the area.

Los Abuelos thrived during the Middle Preclassic (1000 B.C. to 400 B.C.) and Late Preclassic periods (400 B.C. to A.D. 300) before being abandoned and then reinhabited during the Late Classic period (A.D. 600 to 900). It has an astronomical complex with buildings positioned in such a way that solstices and equinoxes can be recorded precisely, the statement said. The remains of a human burial were found at the site, along with the remains of two felines, pottery vessels, shells and arrowheads.

Archaeologists also discovered an altar in the shape of a frog and an engraved stone slab known as a stela. Once the Mayan writing on the stela is translated, it may provide more information about the site and the people who lived there.

Another newly found city, which archaeologists named "Petnal," has a 108-foot-tall (33 meters) pyramid, the statement said. The top of the pyramid is flat and has a room that houses the remains of murals on its walls. Red, white and black from the murals can still be seen, but more research is needed to determine what the murals depict.

Petnal was likely a political center, according to the statement. A frog-shaped altar was also found there. The frog is perceived as a symbol of fertility and rebirth in Maya mythology, wrote researchers Robert Sharer and Loa Traxler in their book "The Ancient Maya: Sixth Edition" (Stanford University Press, 2006). Frog altars have been found at other Maya sites and presumably would have been used in rituals.

The third newly found city, which the archaeologists dubbed "Cambrayal," has a network of canals that originates in a water reservoir at the top of a palace, the statement reported. The main purpose of the canals may have been for removing waste.

"It's especially exciting to learn about the Los Abuelos site," Megan O'Neil, an associate professor of art history at Emory University who was not part of the excavation team, told Live Science in an email. The stone sculptures found at the site "are especially poignant and are similar to many other examples of Maya people making offerings to vital sculptures and connecting with their ancestors by interacting with sculptures from the past."

O'Neil noted that it was important that archaeologists found the remains of intact ceramic vessels during their excavation. In the past, this region was heavily looted and the pottery made by the ancient Maya was taken and sold on the international market. The new finds may "help reconnect items in private and museum collections with their places of origin and deposition, helping return memory to those ceramics, to these sites, and to Maya people living in this region and across the world," O'Neil said.

The discoveries of the three cities, along with other newly found sites in the region, were made by a team of archaeologists from Slovakia and Guatemala who were part of the Uaxactún Archaeological Project (PARU), which searches for Maya ruins near the Maya city of Uaxactún. Since 2009, PARU has discovered 176 sites, although only 20 have been excavated. Live Science reached out to archaeologists involved with the research, but they did not answer questions by the time of publication.

All over the world, frogs are being wiped out by the chytrid fungus. At least 500 species have declined, including as many as 90 species now presumed extinct.

This catastrophic and ongoing biodiversity loss surpasses the devastation wrought by other notorious invasive species such as cats, rats and even cane toads. Short of removing species from the wild and treating them in captivity, few strategies exist to deal with the chytrid threat.

Our new research, published in the journal Nature, offers a promising option.

Outbreaks of chytrid (pronounced "KY-trid") are more common in cold winter months — just like seasonal human flu. We found a way to combat these winter outbreaks using heat. Our purpose-built "frog saunas" allow affected amphibians to warm up and bake off their infections. They are so simple you can build a frog sauna using supplies from the hardware store.

Why should we care about frogs?

If frogs' good looks are not enough for you to care about their welfare, perhaps learning how they contribute to the environment or human health will pique your interest.

Frogs eat insects that carry and spread human diseases. Their skin is also a rich source of new medicines that could help us combat antibiotic-resistant "superbugs" or curb the startling increase in opioid addiction.

The frogs themselves are food for many predators, including humans.

Often starting life as a tadpole eating algae, before morphing into a carnivorous adult, frogs carry energy from aquatic ecosystems onto land — where it can be transferred throughout the food web. So losing a single frog species can have serious flow-on effects.

The origin and spread of chytrid

It's likely the chytrid fungus originated in Asia, where the pathogen seems to coexist with native amphibians. But chytrid is deadly elsewhere, possibly because other frogs have no natural defenses.

Chytrid harms frogs by disrupting the integrity of their skin, depleting electrolytes needed for heart function. Infected frogs can die of cardiac arrest.

Chytrid has spread worldwide through the trade of amphibians, becoming a seemingly permanent part of ecosystems. As eradicating chytrid from the wild is not possible, we need a way to help frogs battle infection.

Related: New fungal infection discovered in China

Introducing frog saunas

Research has shown chytrid is worse in winter. My colleagues and I wondered whether, if frogs had access to warmth during winter, could they fight off infection?

The fungus can't tolerate high temperatures, so if we gave frogs a place to stay warm — even for a few hours a day — perhaps they could survive and recover.

We tested this idea, both in the laboratory and in outdoor experiments.

First we established that endangered green and golden bell frogs will select temperatures that reduce or eliminate chytrid infections, when given the opportunity.

Then we conducted experiments in the lab, with 66 infected frogs. The group given the option of choosing the temperature they liked best rapidly cleared their infection. The group placed in a set, warm temperature also cleared their infection, but it took longer. The low-temperature control group remained infected.

Next, we wanted to see what would happen if frogs that cured infections with heat would still get sick. Or were they immune? The group of 23 heat-cured frogs were 22 times more likely to survive the second infection than the 23 frogs that were heat-treated but not previously infected. So frogs cured with heat acquire resistance to future infections.

Finally, we wanted to see if this could work in a natural setting. We ran outdoor experiments with 239 frogs. Half were infected with chytrid one week before the experiment began. Then they were placed in enclosures with artificial structures that heat up in the sun, called "frog saunas". But the frogs could choose from shaded and unshaded areas, with or without saunas.

We found frogs flocked to the sunny saunas, heated up their little bodies, and quickly fought off infection. Think of frog saunas as little factories that pump out healthy, chytrid-resistant frogs.

The frog saunas could be used on a wider scale. We believe they would be best suited to supporting populations of Australian green and golden bell frogs, but they could be useful for other species too.

The saunas are made of inexpensive materials that can be found at your local hardware store, making them accessible to the general public and wildlife managers alike.

We are already building shelters at Sydney Olympic Park, working with Macquarie University and the Sydney Olympic Park Authority. The park is home to one of the largest remaining populations of green and golden bell frogs.

Want to get involved?

You can become a citizen scientist and help save frogs from extinction. Start by downloading the FrogID app to learn how frogs are faring. Record frog calls with the app for scientists to identify them. This helps provide valuable data for frog conservation.

Build a frog sauna for your backyard, to help keep them healthy through winter.

It's essentially a brick-filled greenhouse, warmed by sunlight. All you need is some common clay ten-hole masonry bricks, black paint and cable ties — and a little greenhouse to put the sauna inside.

Changing the fate of frogs

Since the discovery of chytrid more than 25 years ago, the pathogen has been a seemingly insurmountable challenge to endangered frog conservation. Now, we have developed a promising, inexpensive and widely applicable strategy to combat chytrid.

Amphibians are such a diverse group that no single approach will be suitable for all species. So this is no silver bullet. But a useful tool for even one threatened or endangered species is cause for optimism.

The concept could also be applied to other wildlife diseases, where differences between the physiology of the host and pathogen can be exploited.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Tarantulas are hairy so that the army ants cleaning their homes don't eat them alive, a new study suggests.

The study, published Aug. 6 in the Journal of Natural History, proposes several new ideas about tarantula relationships with other species, including their surprisingly passive but still occasionally violent interactions with predatory ants.

Predatory ants, or army ants, are known to hunt spiders alive, but when these ants were observed scavenging for food in South American tarantula burrows, the ants tended to ignore adult tarantulas as well as tarantula offspring. In the rare instances when the ants did attack, the tarantulas' stiff hairs offered adequate protection.

"The dense hair covering the tarantula's body makes it difficult for the ants to bite or sting the spider," study lead author Alireza Zamani, an arachnologist at the University of Turku in Finland, said in a statement. "Therefore, we believe that the hairiness may have evolved as a defence mechanism."

Related: Deadly male funnel-web spider 'Hercules' breaks record as biggest ever discovered

Zamani and his colleagues explored the complex relationships between tarantulas and other animals by reviewing previous scientific studies and gathering new observations from the field and social media.

The researchers found that army ants help fossorial tarantulas — those that live in burrows — by removing old food from their burrows. However, the spiders still needed protection in case the ants got bitey. This hair-defense hypothesis is supported by previous studies that suggested burrowing tarantulas cover their egg sacs in hairs to help stop ants from getting at them.

Furthermore, the team discovered that less hairy — and therefore potentially more vulnerable — arboreal tarantulas, including Avicularia hirschii in Peru, have developed different defense strategies against ants. For example, in one observation, the researchers watched A. hirschii hang from the tip of a leaf to escape ants on the hunt for prey, according to the statement.

While tarantula-ant relationships can get strained, the researchers found that tarantulas enjoy friendlier interactions with amphibians, which sometimes live in their burrows. The study described more than 60 partnerships between tarantulas and amphibians across 10 different countries, as well as relationships with snakes and other spiders.

"Apparently, the frogs and toads that live within the retreats of tarantulas benefit from the shelter and protection against their predators," Zamani said. "In turn, they feed on insects that could be harmful to the spider, its eggs, and its juveniles. It seems that tarantulas might not be as scary and threatening as their reputation suggests."

Breeding seasons can be dangerous for male frogs that attempt to impress a potential mate: They can quickly find themselves being dragged off and eaten by an unimpressed female, researchers have discovered.

For the first time, scientists in Kooragang Island in New South Wales, Australia have observed adult female green and golden bell frogs (Litoria aurea) preying on their male counterparts during breeding season. They detailed their findings in a study published June 12 in the journal Ecology and Evolution.

The researchers first observed this behavior during a survey when they heard a high-pitched squeal.

"You hear it sometimes in the field, and it's often a frog that's being predated upon," study lead author John Gould, a postdoctoral researcher in population ecology at the University of Newcastle, Australia, told Live Science.

After following the screams, Gould discovered the distress noises were coming from a male with its thigh almost completely ingested by a larger female. She was dragging him into a hole by the bank of a pond.

"The male frog really did try to stop this from occurring, so it was grabbing onto anything around it, like sticks in the ground, to stop itself from being dragged in," Gould said.

The male eventually managed to escape. The observation prompted Gould and his team to compare their nocturnal field observations of three consecutive breeding seasons with other studies that reported instances of sexual cannibalism.

Cannibalism is well-documented in amphibians, but most reported cases involve either adults cannibalizing juveniles that were emerging from the water or tadpoles cannibalizing each other, Gould said.

Amphibian cannibalism typically occurs when large numbers of the animals congregate in the same area, such as when tadpoles emerge from eggs, and when there are notable size differences between predator and prey.

Many species of frogs are sexually dimorphic — adult females are often significantly larger than males.

"There’s a very good opportunity that females can exploit their male counterparts, not only as breeding partners, but potentially as prey," Gould said.

The researchers speculated that this cannibalism may act as a natural selection process.

Females may differentiate between potential mates or prey depending on the quality of their calls during breeding season. Larger males with deeper calls may be seen as better breeding partners, leaving smaller, inferior males as potential meals.

However, Gould suggested that the superior mates may not escape predation either. Instead, once females have dumped all their eggs after breeding, they may choose to eat their mate — similar to female praying mantises, which decapitate and eat their mates during or after mating.

"It's risky for male frogs out there. They're calling their little hearts out to find a mate, but they just have to take on this extra risk of maybe being used as prey," Gould said.

Scientists still don't know for sure what influences these cannibalistic behaviors. Observations of sexual cannibalism are rare because they occur quickly. However, this may not mean that they are infrequent, Gould said.

Gould points out that field observations of amplexus — when a male frog mounts a female to fertilize her eggs — are also relatively rare, even though scientists know it is necessary for breeding.

Further research is needed to establish how frequent these cannibalistic events are and how they impact the local populations of green and golden bell frogs, the team said.

Don't underestimate the tongue, a muscular organ that humans use for licking, breathing, tasting, swallowing and speaking. But this organ varies widely in color, shape, length and function across the animal kingdom. Whereas human tongues are pink and typically just over 3 inches (7.6 centimeters) long, the anteater has a 2-foot-long (60 cm) tongue and the blue-tongued skink has a brilliant blue one.

Here's a look at 20 amazing animal tongues and the science behind them.

Giraffes

If you've ever seen a giraffe's impressive 21-inch-long (53 cm) tongue, you'll know that it's not pink. Rather, the tallest living animal in the world has a dark-colored tongue that looks like a mix of purple, blue and black. That's because giraffes (genus Giraffa) tongues are covered with a lot of the pigment melanin, which acts as a type of sunblock to protect the licker while it reaches for tender leaves.

Giraffes have such long tongues that they can even use them to clean out their ears, according to Mental Floss.

Gila monsters

The Gila monster (Heloderma suspectum) lives up to the "monster" part of its name with its forked tongue. It's thought that the gila's forked tongue helps it smell in "three dimensions," meaning that the two tips can pick up the same odor and then distinguish the wafting chemical gradients in the air, which, in turn, helps the reptile zero-in on the location of the smell's source, Andrew Durso, a herpetologist at Florida Gulf Coast University, wrote in The Conversation. 

When the venomous lizard gets hungry, it flicks its sensitive tongue in and out, picking up chemical information about its surroundings. Then, the Gila monster's Jacobson's organ, a part of the olfactory (smelling) system in its nasal chamber, analyzes this information, letting the lizard know whether potential prey, such as small mammals, frogs, lizards, rodents and insects, are nearby.

Pangolins

As the only known mammal with scales, pangolins are weird creatures. Their sticky tongues are just as strange. The pangolin's tongue is connected not to the bottom of its mouth, but to the bottom of its ribcage. When it's not busy snatching up insects, such as ants and termites, the tongue hangs out in the pangolin's chest cavity.

When the pangolin's tongue is extended, it can measure up to 16 inches (40 cm) long, or longer than the animal's head and body combined, according to the BBC. 

Sun bears

"The tongue of the sun bear (Helarctos malayanus) is surprisingly long, measuring up to 10 inches (25 cm), according to Guinness World Records. This feature helps the bear channel its inner Winnie the Pooh; its lengthy tongue can extract honey from beehives, a trick that landed it the nickname of "honey bear," according to National Geographic.

Hippos

Much of the hippo's evolutionary history remains shrouded in mystery, according to National Geographic. Their giant tongues are no exception. In a 2010 study published in the journal The Anatomical Record, researchers looked at the tongues of a young and old common hippopotamus (Hippopotamus amphibius amphibius) with scanning electron microscopy and conventional light microscopy. (The 49-year-old female hippo's tongue was 24 inches (60 cm) long, while the 4-year-old male's was 18 inches (45 cm) long.) 

The team found that hippo tongues have features similar to a few types of animals: odd-toed ungulates (such as donkeys, which digest plant cellulose in the intestines, not the stomach), ruminants (such as cattle, which have four-chambered stomachs) and omnivorous, non-ruminant mammals (such as pigs, which have simple stomachs). 

Meanwhile, hippos use their three-chambered stomachs to help them digest grass. The animal's herbivorous diet and unique evolutionary history may explain "these mixed morphological features of the tongue," the researchers wrote in the study.

Penguins

Which tongue has more bristles than a hairbrush? It's none other than the penguin's.

The penguin's tongue does not have taste buds, but it does have loads of bristles made out of keratin, the fibrous protein that makes up human hair and nails. These bristles help the penguin grab wriggly krill and fish, according to the Smithsonian. 

Red-bellied woodpeckers

Woodpecker tongues — made of bone, cartilage and muscle — need to be really, really long so the birds can nab grubs hiding deep in trees. But a woodpecker's mouth isn't big enough to house that long tongue. So, what's the workaround? When it's not in use, the tongue goes into "self storage" by wrapping around the woodpecker's skull.

"The cordlike base of the tongue extends back out of their mouth on each side, winding behind and onto the top of their head, sometimes extending so far forward that it reaches the nostril," Larry Witmer, a professor of anatomy and paleontology with the Department of Biomedical Sciences at Ohio University, told Live Science. "When they need to unleash the weapon, the tongue basically unwinds from around the head to project into a crevice to capture its prey. It's a remarkable mechanism that's evolved independently in several kinds of birds, including hummingbirds."

You can check out this video of Witmer describing a red-bellied woodpecker skull and tongue. 

Tongue-eating parasites

This technically isn't a real tongue; it's a parasite that destroys a fish's tongue and then becomes a "substitute" tongue. In other words, this bug-like creature (Cymothoa Exigua) is a tongue-eating parasite. 

After the parasite enters through the fish's gills, it latches onto the tongue with its seven pairs of legs and (brace yourself) begins to feed on the tongue like a vampire. Soon, the tongue withers and drops off, but the parasite remains, masquerading as the fish's new tongue.

Lions

Just like other cats, the mighty lion (Panthera leo) uses its tongue to groom its fur. Feline tongues are very effective combs; they're covered with tiny spines known as papillae, which are sharp, hollow and curved backward toward the cat's throat, according to a 2018 study in the journal Proceedings of the National Academy of Sciences. These spines help the cat deliver cleansing saliva to its fur, which later cools the cat as it evaporates. 

Cats don't care whether their prey tastes sweet, however. Their tongues have a useless version of the gene Tas1r2, which encodes proteins that combine to form sugar-detecting sensors on the tongue, National Geographic reported. 

Giant leaf-tailed geckos

Watch out! If the giant leaf-tailed gecko (Uroplatus fimbriatus) feels threatened, it will make sure you do, too. When this gecko is disturbed, it opens its jaws wide, flashing its bright red mouth and tongue before it releases a piercing distress call that sounds just like a child's scream, Smithsonian's National Zoo reports.

Frogs

Frogs are famous for their fast tongues, and for good reason. More than 4,000 frog species can grab objects with their tongues faster than the human eye can blink, according to Alexis Noel, a research engineer at the Georgia Tech Research Institute who studies frog and cat tongues, previously reported on her website. She noted that frog mouths have a unique anatomy: "Unlike humans, frog tongues are connected at the front of the lower jaw, rather than at the back of the throat."

In addition to its speed, the frog tongue is strong. The tongue of the horned frog can pull objects that are about 1.4 times the frog's body weight, a 2014 study in the journal Scientific Reports found.

Blue-tongued skinks

Blue-tongued skinks, natives of Australia and New Guinea, use their vibrant blue tongue to startle predators, according to the San Diego Zoo. When threatened, the skink puffs up its body so that it appears larger, opens its mouth and hisses while it sticks out its tongue.

Eagles

Eagles have tongues with backward-facing barbs called "rear-directed papillae," which help them swallow prey, according to the Center for Conservation Biology, a research group at the College of William and Mary and the Virginia Commonwealth University. When eagle parents are feeding their young, they use their tongues to help keep away large bones, furry chunks and sharp fins that could cause the chicks to choke, according to the Raptor Resource Project, a nonprofit bird group based in Iowa.

Alligator snapping turtles

The alligator-snapping turtle (Macrochelys temminckii) has a clever trick; it uses its little pink tongue as a fishing lure. While these turtles are known to forage for food along the bottoms of rivers, lakes and swamps, they can also lie still with their mouths open and tongues wriggling, as they wait to ambush fish that mistake their tongues for worms, according to the Nonindigenous Aquatic Species program of the U.S. Geological Survey. 

Parrots

How do parrots and parakeets (a type of parrot) mimic human speech? It turns out that Polly can adjust her nimble, muscular tongue so that it modulates the sound coming from her voice box, according to Science magazine. In one small experiment, repositioning the tongue of five dead monk parakeets (Myiopsitta monachus), whose vocal tracts were connected to speaker systems, led to changes in pitch and loudness, which is key for forming vowels in speech, according to a 2004 study in the journal Current Biology.

Emperor tamarins

While humans might take note of the emperor tamarin's distinctive mustache, its fellow emperor tamarins (Saguinus imperator) may have their eyes on something else: the tongue. When these primates are displeased, they tend to flick their tongues, quickly moving the tongue in and out of the mouth, according to Apenheul Primate Park, a zoo in the Netherlands. The emperor tamarin also communicates with shrill calls, chirps, hisses and facial expressions, which, combined with tongue flicking, help keep its troop together and alert to danger, according to the New England Primate Conservancy.

Flies

That hairy appendage dangling out of a fly's mouth may look like a tongue, but it's not. Scientists call it the labellum, and it's the primary taste organ for the Drosophila fruit fly, according to a report from Indiana Public Media. The labellum is attached to the fly's straw-like proboscis, which allows the pest to slurp up food. A word to the wise: Put your leftovers away if you've got a fly problem. These buzzing beasties puke saliva and digestive juices onto food before eating it, because these acids dissolve the food the fly wants to suck up, according to HowStuffWorks. 

Giant anteater

The giant anteater (Myrmecophaga tridactyla) doesn't have teeth, but it doesn't need them; instead, it uses its roughly 2-foot-long (60 cm) tongue to eat up to 30,000 ants and termites a day, according to the San Diego Zoo. This narrow and spaghetti-like tongue, which is attached to the mammal's sternum, is covered with tiny, backward-pointing spines and sticky saliva to help it grab the tiny insects. The anteater's tongue is fast, too — it can dart in and out of its mouth up to 150 times a minute. 

Chameleons

Chameleons are relatively slow creatures, but their 20-inch-long (50 cm) tongues are fast enough to catch speedy insects, such as locusts, mantids and grasshoppers. The tip of the chameleon's tongue is a ball of muscle, and once it hits prey, that ball transforms into a suction cup. The instant the prey is stuck, the reptile draws its tongue back into its mouth, where its strong jaws crush the catch, according to the San Diego Zoo. 

Hummingbirds

Hummingbird tongues were misunderstood for more than 180 years, until a 2015 study set the record straight. Initially, scientists thought that hummingbird tongues used capillary action — in which liquid can flow through narrow channels, even against gravity — to pull up floral nectar. But actually, these tongues act as elastic micropumps, according to the journal Proceedings of the Royal Society B: Biological Sciences. 

High-speed videos showed that the hummingbird flattens the tip of its outstretched tongue against a desirable flower, then reshapes its tongue so it can fill with nectar. Next, the top of the tongue (the part by the mouth) bends, which produces elastic energy that can draw the nectar out of the flower. This process lets the bird slurp up its food at fast speeds, the study found.

Editor's note: This countdown was originally published on Aug. 28, 2020 and updated on July 10, 2024 to give it a new format and update links.

A newly described species of proto-amphibian that lived 270 million years ago has been named after Kermit the Frog.

Paleontologists at the Smithsonian National Museum of Natural History rediscovered the ancient amphibian ancestor's fossilized skull while looking through the museum's archives, according to a statement.

The "creature’s cartoonishly wide-eyed face" immediately reminded the researchers of the "Muppets" character Kermit the Frog, so the scientists named the species Kermitops gratus. They described the animal in a study published Wednesday (March 21) in the Zoological Journal.

"Using the name Kermit has significant implications for how we can bridge the science that is done by paleontologists in museums to the general public," lead study author Calvin So, a doctoral student of biological sciences at The George Washington University, said in the statement. "Because this animal is a distant relative of today's amphibians, and Kermit is a modern-day amphibian icon, it was the perfect name for it."

Related: World's tiniest fanged frog with males that 'hug' their babies discovered

The skull, which measures roughly an inch (2.5 centimeters) long and has "oval-shaped eye sockets" was first unearthed by Nicholas Hotton III, a paleontologist and curator at the Smithsonian. Hotton discovered the skull while exploring the Red Beds, a fossil-rich rock outcrop in Texas. During that field season, Hotton and his team discovered so many fossils that "they were not able to study them all in detail," according to the statement.

Then, in 2021, Arjan Mann, a postdoctoral paleontologist at the museum, and the study's co-author, found the skull in the archives.

"One fossil immediately jumped out at me — this really well preserved, mostly prepared skull," Mann said in the statement.

The paleontologists noticed that the skull contained unique physical traits that set it apart from other tetrapods, the ancient ancestors of amphibians. For example, the part of the skull with the animal's eye sockets "was much shorter than its elongated snout." Scientists think that the animal likely "resembled a stout salamander" and used its longer snout to "snap up tiny grub-like insects," according to the statement. 

The researchers determined that the animal is not a frog but rather from the order temnospondyls, which are thought to be the common ancestors of Lissamphibia, the group that includes all modern amphibians, such as frogs, salamanders and caecilians.

The new find could help researchers better understand how these groups evolved and fit together on the evolutionary tree.

"Kermitops offers us clues to bridge this huge fossil gap and start to see how frogs and salamanders developed these really specialized traits," So said in the statement.

A team of researchers has identified a teeny new frog species that's no bigger than a quarter. But don't let its diminutive size fool you: This one has fangs.

The new species, Limnonectes phyllofolia, which the researchers described in a new study published Dec. 20 in the journal PLOS One, was found in the lush forests of Sulawesi, an Indonesian island renowned for its biodiversity — including fanged frogs.

The frogs use these teeth like weapons to tussle with their competitors for territory to lay their eggs. Researchers think the frogs may also use their fangs to pierce through the protective casings of prey such as insects and crabs. (Technically, the saber-like structures, which are situated in the frogs' lower jaws, are bony protrusions, not teeth.)

The fact that some frogs have teeth may come as a surprise. In fact many frog species have tiny teeth that line the upper jaw — though these are near-invisible in most. However the 70-plus species of the genus Limnonectes are known for the more notable fang-like protrusions on their lower jaws. These fanged amphibians are spread across East and Southeast Asia, and the dense rainforests of Sulawesi are a hotspot, home to 15 of those species. Some of the frogs in the genus are huge, such as the Blyth’s river frog (Limnonectes blythii) which can weigh over 2.2 pounds (1 kilogram). But the genus' newest member, L. phyllofolia, is just 1.2 inches (3 centimeters) long, meaning it's the smallest fanged frog in the world. 

Related: These female frogs fake their own deaths to get out of sex

But its minuscule size isn't this frog's only unusual trait. Researchers first discovered the new species when they noticed some strange nesting behavior in the Sulawesi rainforest. They spied unmistakable clusters of frog eggs spread across mossy boulders, fern fronds and the leaves of sapling trees, which surprised them because most frogs lay their delicate eggs in riverbanks and ponds to prevent the gel-like sacs that surround the developing tadpoles from drying out. 

What's more, when the researchers hung around to find out which animal these above-ground nesting sites belonged to, they noticed the tiny frogs that returned to their eggs were all male. "Male egg guarding behavior isn't totally unknown across all frogs, but it's rather uncommon," study lead author Jeff Frederick, a postdoctoral researcher at the Field Museum in Chicago, in a statement. Males are the primary caretakers in only one other fanged frog species, L. arathooni, which lays its eggs at ground level in stream banks and ponds. 

The unusually doting dads of L. phyllofolia — whose second name means "leaf-nester" — get around the threat of desiccating eggs by seemingly "hugging" their brood, coating the eggs in compounds that are excreted from their skin to keep their progeny moist and ward off bacterial and fungal infection, the researchers said in the statement. 

Whether laid on a leaf or a mossy rock, each nest had been positioned about 3 to 6.5 feet (1 to 2 meters) above a body of water. This means that when it comes to hatching time, the tadpoles can conveniently slither out of their eggs and plop directly into the water. 

The researchers think this unusual nesting behavior might help explain why the frogs evolved to be so small and have tiny pinprick fangs compared with their relatives' larger teeth. Choosing nest sites above ground and away from other competitors seems to work well enough at protecting the nest from competitors and predators that these frogs don't need a hefty body weight or impressive gnashers to do the job.

The researchers hope that the discovery of L. phyllofolia will provide extra motivation to study these creatures. Of the 15 species in Sulawesi, only five have been formally described, they noted. "Our findings also underscore the importance of conserving these very special tropical habitats," Frederick said. "Learning about animals like these frogs that are found nowhere else on Earth helps make the case for protecting these valuable ecosystems."

In the excerpt below taken from "Beautiful Experiments: An Illustrated History of Experimental Science" (The University of Chicago Press, 2023), Philip Ball dives into the 17th and 18th century experiments that sought to figure out the answer to a fundamental question: What induces eggs to develop? From microscopic observations of spermatozoa to special little sperm-catching trousers for frogs, Ball reveals how we came to understand fertilization. 

It was always clear that for the reproduction of humans and other mammals, both the male and the female have a role. But what role, exactly? Aristotle proposed that both sexes contribute a kind of generative principle called "sperma," which combine to produce the rational human soul in the growing fetus in a process he called "epigenesis." 

Reflecting the chauvinistic attitude that shaped most theories of procreation until modern times, the male principle was considered the active element, which grew like a seed in the passive receptacle supplied by the woman. In one of the earliest recorded examples of experimental science, Aristotle carefully opened and examined chick eggs at different stages from fertilization to birth in order to watch the development of the fetuses. 

In the 17th century, the English physician William Harvey, while largely endorsing the Aristotelian position, placed more emphasis on the role of the egg from the female. Ex ovo omnia, as he put it in 1651: everything comes from an egg, a position called ovism. But Antonie van Leeuwenhoek's microscopic observations of spermatozoa in the 1670s led to the notion that the developing body is somehow inherent already in the head of the worm-like entities seen in sperm (spermatozoa literally means "sperm animals"). 

The concept was strikingly illustrated in 1694 by the Dutch microscopist Nicolaas Hartsoeker, who drew a sperm with a fetal homunculus packed into the head, complete with tiny limbs. In this preformationist view the body was already fully formed, whereas in the [epigenesis] view it developed from an unstructured seed. 

It was all largely conjecture, because of the difficulties of making observations and experiments on human conception. Then, as still today, much of what was known about embryology relied on studies of other animals. In the mid-18th century, an Italian physiologist and priest named Lazzaro Spallanzani set out to investigate the precise role of male semen by studying reproduction in frogs. Spallanzani has been described as having a "lust for knowledge:" a passion that sometimes seemed to exceed propriety, as when he was said to have begun expounding enthusiastically to a group of dignitaries about the mating of frogs he had noticed in a body of water during travels in Constantinople. 

Related: These female frogs fake their own deaths to get out of sex

That was surely a rather indecent topic of discourse for a man who had been ordained in the Church. Frogs do not actually copulate, though. Rather, the female lays her eggs, onto which the male then deposits his semen. 

Although Spallanzani shared Harvey's epigenetic view of development from a fertilized egg, he suspected that the spermatozoa play no role, but are instead a kind of parasite. It is the thinner, liquid component of the semen, Spallanzani thought, that provides the generative principle. 

To test that idea, Spallanzani needed to collect frog sperm and separate the microscopic "worms" from the seminal fluid. He borrowed an idea from the French scientist René Antoine de Réaumur, who in 1736 attempted to study fertilization in frogs by fitting the males with tiny trousers made from taffeta and pig's bladder, so that he might collect and study their sperm. He had little success with this, however, because the frogs wriggled out of their garments. But Spallanzani's prophylactic frog trousers were more successful. By applying some of the semen obtained in this way to frog eggs, he conducted the first known example of artificial insemination. 

Spallanzani never managed to elucidate the connection between spermatozoa and fertilization, however. After filtering the collected sperm to separate the liquid from the thicker residue containing spermatozoa, he found that only the latter could cause fertilization — and yet, to the bemusement of many historians of science, he still believed that the fertilizing capacity resided with the liquid. 

In one set of experiments he kept toad sperm and eggs on pocket-watch glasses just a few millimeters apart to see if the eggs might be fertilized by some intangible "aura" emanating from the sperm (they were not, of course). Some think Spallanzani was too much in thrall to a kind of preformationist ovism, believing that the embryo's form was already dormant in the egg and needed only the barest stimulus from semen to start it developing. 

At any rate, he exemplifies how, even if a scientist does the right kind of experiment, there's no guarantee that they will draw the correct conclusion from it. Spallanzani later extended his investigations to dogs, collecting semen from a male and injecting it with a syringe into the uterus of a bitch. Seeing the resulting pregnancy and the birth of pups was, he wrote, "one of the greatest joys of my life." He also experimented with preserving sperm using ice to see if it retained a capacity to fertilize.

Reprinted with permission from Beautiful Experiments: An Illustrated History of Experimental Science by Philip Ball, published by The University of Chicago Press. © 2023 by Quarto Publishing plc. All rights reserved.

Paleontologists have discovered the earliest molecular evidence of the toxic pigment that causes red hair in the fossil record — in 10 million-year-old frog fossils.

The ancient amphibians had preserved fragments of pheomelanin (also spelled phaeomelanin), a yellowish-red pigment that produces ginger-colored hair in animals, including humans, according to a study published Oct. 6 in the journal Nature Communications.

"It's the exact same pigment that causes red hair in us," lead study author Tiffany Slater, a postdoctoral researcher of paleobiology at University College Cork in Ireland, told Live Science. "But that doesn't mean that the frogs were necessarily ginger colored when they were alive."

Pelophylax pueyoi is an extinct species of large frog that lived in what is now Spain during the Early Miocene (23 to 5.3 million years ago). Their fossilized remains are part of a museum collection and were loaned to the researchers, according to a statement.

Related: These female frogs fake their own deaths to get out of sex

To get a better understanding of how the pigments degrade during the fossilization process, the researchers examined liver tissues taken from the frog remains (the liver is known for containing high levels of pheomelanin) along with black, ginger and white bird feathers, which dovetailed with a previous study of theirs, according to the statement.

Their findings showed traces of pheomelanin contained within the liver tissues of the ancient frogs. 

"Fossils are invariably altered by the ravages of heat and pressure during burial, but that doesn't mean that we lose all original biomolecular information," study co-author Maria McNamara, a professor of paleobiology at University College Cork, said in the statement. "Our fossilization experiments were the key to understanding the chemistry of the fossils and prove that traces of biomolecules can survive being cooked during the fossilization process."

Slater said their experiments are "pushing the boundaries" of what they thought was possible regarding the information a fossil can contain. 

However, scientists are still learning how and why pheomelanin evolved in the first place, especially as it can be toxic to animals, Slater said. Pheomelanin is a type of melanin, a substance in the body that produces hair, eye and skin pigmentation. In humans, there are two types of melanin — eumelanin, which is responsible for dark colors, and pheomelanin, which produces blond and ginger hair colors and pale skin. While eumelanin helps protect from the sun's harmful UV rays, pheomelanin does not.

"It's toxic in the way that it interacts with sunlight, which can cause damage to certain cells," Slater said. 

The scientists hope that further study can lead to a better understanding of the evolution of different pigments within the fossil record, providing an insight into the colors of ancient animals.

"This is the first molecular record of pheomelanin in the fossil record, and we need to start looking for pigments in more and older fossils," Slater said. "Then we can start [to rebuild] what it says about evolution, and the big question of why ginger pigments evolve despite them being toxic to animals."

In the video above, the female frog in the top left tank fakes death to avoid sex with the male. 

Female frogs have developed a number of ways to get out of sex, including rolling, grunting and even faking their own deaths, scientists have discovered.

European common frogs (Rana temporaria) are known as "explosive" breeders that gather in their dozens to mate in ponds. Usually, males outnumber females, which means six or more males may compete to mount a female at one time in what is known as a mating ball.

"In some cases, the female might be killed inside these mating balls," Carolin Dittrich, a researcher at the Natural History Museum in Berlin, told Live Science.

But the females have developed several techniques to avoid mating. "Rather than being passive and helpless, we find that females can use three key strategies for avoiding males they don’t want to mate with — either because they aren't ready to breed or do not want to mate with a certain male," Dittrich said.

Related: Female spiders play dead during sex so males don't have to worry about being eaten

The researchers collected male and female European common frogs from a pond during the breeding season and divided them into tanks filled with water, so each tank contained two females and one male. They then filmed the frogs for an hour. 

Of the 54 females that were grasped by a male, 83% of them rolled onto their back in response.

"This puts the male underwater, so the male lets go to avoid drowning," Dittrich said. 

The team also found that 48% of the females that were mounted by males emitted grunts and squeaks. The grunts mimicked "release calls" that male frogs usually make to ward off other males from mounting them, Dittrich said. "But it's unclear what the higher frequency squeaks are signaling," she added. 

The researchers also found that a third of females lay motionless with their limbs outstretched for around two minutes after being mounted by a male.

"To us, it appears as if the female is playing dead, although we can't prove it's a conscious behavior," Dittrich said. "It could just be an automatic response to stress."

Smaller female frogs, which are usually younger, were the most likely to use all three deterrence strategies, whereas larger, likely older, females were less likely to fake their own death, Dittrich said. As a result, smaller female frogs were generally better at escaping a male's advances than larger ones, she added.

It could be that younger females, which have lived through fewer breeding seasons, become more stressed upon being mounted by males, causing them to respond more strongly, Dittrich said. 

Overall, 46% of females who were mounted by a male successfully escaped.

Although the experiments are quite different to the real-world scenario, these strategies have been seen in the wild, Dittrich said. 

Faking death as a strategy to escape unwanted males has been documented in just a handful of other animals, including dragonflies, spiders and in one other amphibian species — sharp-ribbed newts (Pleurodeles waltl). 

Understanding mating behaviors like these could help support conservation efforts in the future, if we try to breed species back from the brink, Dittrich noted. "Although the European Common frog is more common than many other species, there has been a steady decrease in population numbers in the past 17 years due to the lack of rain and droughts," she said.

The study was published Wednesday (Oct. 11) in the journal Royal Society Open Science.

Extreme weather events and mass extinctions are some of the most serious effects of climate change, but a warming world is having many other— and less obvious — effects on our planet. From bumpier plane rides to sex-changing lizards, here are 15 of the most unexpected effects of a warming world.

Baseball home runs increase

Home runs in Major League Baseball seem to be increasing as temperatures rise. In a study published April 7 in the journal Bulletin of the American Meteorological Society, researchers said that as warmer air is less dense, baseballs fly farther after being batted away. 

They found that, between 2010 and 2019, more than 500 homers — accounting for 1% of home runs — could be put down to unusually hot days as a result of global warming.  They also predicted home runs could be 10% more common by 2100, compared with averages between 2010 and 2019. Playing more games at night when temperatures are milder could help counter the impact on the sport, the scientists suggested. 

Shrinking frogs croak in higher pitches 

As the world warms, male coquí frogs (Eleutherodactylus coqui) in Puerto Rico are croaking in higher pitches. In a study presented on May 8 at the 184th Meeting of the Acoustical Society of America, researchers revealed how rising temperatures are causing these amphibians to shrink, raising the pitch of their croaks. 

Male coquí frogs call to mark their territory and warn off rivals. The scientists found that frogs living nearer the base of a mountain, where it is warmer, croaked in higher pitches than larger frogs living at higher altitudes, where it is cooler. When researchers returned to the same slopes two decades later — when global temperatures had increased — they found that frogs were calling in higher pitches no matter where they were on the mountain.

Airplane turbulence getting worse 

Climate change is making plane rides bumpier as air streams shift. In a study published June 8 in the journal Geophysical Research Letters, scientists compared climate data from 1979 to 2020 with air turbulence data in the North Atlantic. They found that severe turbulence — which is caused by colliding streams of air that are traveling at different speeds — jumped by 55% from 17.7 hours in 1979 to 27.4 hours in 2020. Moderate levels of turbulence rose by 37% over the same time period. Climate change is likely behind this increase because hotter air means wind speeds and directions are changing more strongly, the researchers wrote in the study.

Sleep loss

By 2010, people had already lost around 44 hours of sleep each year because of hot nights associated with global warming. This could rise to 58 hours of lost sleep per year by 2100 under a high carbon emissions scenario, researchers estimated. In a study published in May 2022 in the journal One Earth, scientists compared sleep data collected using sleep-tracking wristbands from 48,000 people in 68 countries, and found that people sleep later and wake earlier on hotter nights.

Rise in dog bites

Humans are known to commit more violent crimes when the heat ramps up. Now, a study published June 15 in the journal Scientific Reports indicates that canine aggression also rises with the temperatures, with more dog bites recorded on hotter days. By analyzing data on 69,525 dog bites in eight U.S. cities — Dallas, Houston, Baltimore, Baton Rouge, Chicago, Louisville, Los Angeles and New York City — the team found an 11% increase in dog bites on days with high UV and a 4% rise when temperatures were high.

More wildfire lightning 

Global warming will alter lightning patterns around the world — and this may result in more wildfires. In a study published Feb. 10 in the journal Nature Communications, researchers examined "long-continuing current lightning" — a type of lightning known to be the main cause of lightning-induced wildfires. They estimated these strikes will  become 10% more common with each 1.8 degree Fahrenheit (1 degree Celsius) temperature rise. This could amount to a 40% increase in these strikes by the end of the century under a worst-case-scenario climate change projection. 

Related: Yellowstone's geysers at risk of extinction from climate change, tree skeletons reveal

Fewer babies

Hotter days have been linked to a dip in birth rates. In a study published 2018 in the journal Demography, researchers found that days with an average temperature above 80 F (26.7 C) were linked to a 0.4% decrease in birth rates roughly nine months later — the average length of pregnancy —  compared with days with temperatures of between 60 F (15.6 C) and 70 F (21.1 C). Rather than causing a dip in sex drive, the scientists think high temperatures could lower fertility — some studies have found that hot conditions can impair how well sperm swim.

Lizard sex change 

Rising temperatures mean central bearded dragons (Pogona vitticeps) in Australia are changing sex. For some reptiles, sex is influenced by the temperatures their eggs are exposed to as they develop, with higher temperatures linked to more females. In a 2015 study published  in the journal Nature, scientists described how 11 of 131 lizards captured in the wild had male sex chromosomes but warm incubation conditions caused them to develop a female anatomys, with sex-reversed lizards able to lay eggs.

Worse allergies

Rising temperatures are causing earlier and longer springs, which are propelling more pollen into the air, making life that little bit harder for people with allergies like hay fever. In a study published in 2021 in the journal Proceedings of the National Academy of Sciences, scientists found that the sneezing season is getting longer in North America, having increased by 20 days between 1990 and 2018. They also found pollen levels increased by 21% in the same time period. The changes are probably due to global warming and are already worsening allergies, the team wrote. 

Dimmer Earth 

In a study published in the journal Geophysical Research Letters in 2021, scientists analyzed the amount of sunlight reflected from Earth onto the moon between 1998 and 2017 and found our planet appears to be getting dimmer. Their findings revealed that hotter seas have reduced the amount of reflective low-lying clouds above the eastern Pacific Ocean, causing less sunlight to bounce off our planet. As this traps more light energy on the Earth, it could further increase global warming.

Erupting volcanoes 

Many of Earth's volcanoes are covered in ice, but as more of this ice melts due to global heating, the released water could mix with the hot rock and magma beneath to cause more frequent violent explosions. Melting ice reduces pressure on the magma, enabling more bubbles to form inside it. This bubbling magma then puts more pressure on the Earth’s crust above, until the molten liquid explodes through cracks in the crust. This idea was backed up by a study published 2017 in the journal Geology, in which researchers found that between about 4,500 and 5,500 years ago, the number of volcanic eruptions in Iceland dropped significantly when the climate cooled, compared with hotter periods.

Less coffee  

Climate change could halve the amount of coffee-growing land by 2050, a study published Jan. 26 in the journal PLOS One suggested. By modeling three different climate scenarios that limited global warming to either 2.7 F (1.5 C), 4.3 F (2.4 C) or to 7.2 F (4 C), scientists found that the number of regions highly suited for growing coffee — such as areas of Brazil, Vietnam, Indonesia and Colombia — could decline by 50%. 

Shrinking goats

Goats in the Italian Alps are getting smaller as our planet gets hotter. In a study published in the journal Frontiers in Zoology in 2014, researchers analyzed the body mass of juvenile Alpine chamois (Rupicapra rupicapra) living on the mountains between 1979 and 2010 and found they had shrunk by around 25%. Over the study period, the region warmed by 5.4 F to 7.2 F (3 C to 4 C). The scientists said the animals' reduced size appears to be down to the chamois spending more time resting and less time feeding during hot periods.

Deteriorating mummies

After remaining well-preserved for more than 7,000 years in the Atacama Desert, some of the world's oldest mummies have started to degrade while being kept in a museum. These mummies were prepared by hunter gatherers called the Chinchirro. Rising humidity levels amid climate change are thought to have spurred the growth of bacteria that digest the mummies, causing some to turn into a black ooze, according to a report by the Harvard John A. Paulson School for Engineering and Applied Sciences. By testing mummy samples in the lab, scientists identified humidity levels in the museum that would best preserve the historic objects.

Faster tree growth 

Increasing carbon dioxide levels in the atmosphere have spurred trees to grow faster in Central Europe. In a study published in the journal Nature Communications in 2014, scientists found that Norway spruce (Picea abies) and European beech (Fagus sylvatica) trees grew more than twice as fast in 2010 compared with 1960, amid rising levels of carbon dioxide. This greenhouse gas is a key ingredient for photosynthesis, the process by which plants use light energy to produce sugar and oxygen. This sugar can then be combined with oxygen in the process of respiration to release energy for growth.

While most frogs eat a diet rich in insects, one species in Brazil has its own method of nourishment: dunking itself headfirst into a flower's bulb to slurp up its sweet nectar. When the frog comes up for air, pollen grains stuck to its rust-colored body get dispersed as it hops from flower to flower in the forest.

Scientists think this could be the first time an amphibian has been observed pollinating flowering plants, according to a study published in the June issue of the journal Food Webs.

"We observed individuals entering large flowers and leaving covered in pollen without destroying the flower structures," lead author Carlos Henrique de-Oliveira-Nogueira, a graduate student at the Federal University of Mato Grosso do Sul in Brazil, told Live Science in an email. "This was the first time this behavior (actively seeking fruits and flowers) was seen and documented."

It's long been known that species other than bees, including bats and birds, can act as pollinators. But scientists were surprised to see an Izecksohn's Brazilian tree frog (Xenohyla truncata) performing a similar behavior on a Brazilian milk fruit tree (Cordia taguahyensis), known for its creamy-white flowers, according to the study.

One evening, the team watched as two frogs "lapp[ed] up nectar from inside the bell-shaped flowers" in eastern Brazil's Restinga forests and then spread the pollen around, The New York Times reported.

Related: Otherworldly 'Lord of the Rings' frog discovered in the mountains of Ecuador

Normally, frogs prefer to dine on moths and insects, which they capture by sticking out their long tongues. 

"Most frog species are carnivorous in their adult phase," de-Oliveira-Nogueira told Live Science. He said there are other frogs that are known to feed on plant parts. But in Brazil, X. truncata is the only one. "Here, we confirmed how opportunistic X. truncata seems to be. It feeds on both insects and plants — apparently anything that is available for consumption," he told Live Science.

However, he cautioned that more research needs to be done before this species can be classified as a bona fide pollinator. 

"This was amazing and left us with many questions that still need answers," he said. "The species meets some of the requirements to be a pollinator, but we still need further study to actually prove this."

Felipe Amorim, a pollination ecologist at São Paulo State University in Brazil who wasn't involved in the study, agreed.

"We cannot say that these frogs are actually pollinators," Amorim told The New York Times. "They are flower visitors, they are flower-visitor frogs. We have a lot to learn about this novel interaction."

When a glassfrog falls asleep, it vanishes. Nestled atop a lush leaf, the frog's bright green back blends right in, while its underbelly's reddish hue quickly grows transparent. 

Now, a new study in the journal Science reveals that the northern glassfrog (Hyalinobatrachium fleischmanni) pulls off this feat by removing almost 90% of its red blood cells from circulation and packing them into its liver. The findings reveal how one of the only transparent land animals hides its blood. 

"If you really want to be transparent, you need to hide your red blood cells," study co-author Sönke Johnsen, a professor of biology at Duke University in North Carolina, told Live Science. "These glassfrogs are — by some process; we don't know the details — filtering red blood cells out of their blood and cramming them into their livers so tightly that it should create a clot. But it doesn't."

Understanding why these clots never form could have implications for human diseases, the researchers said.

Northern glassfrogs seldom grow larger than 1 inch (2.54 centimeters) in length, and spend most of their adulthood perched on leaves in Central and South American forest canopies, high above the rapidly flowing streams where they lay their eggs. Their underbellies are translucent even when the frogs are awake, allowing an observer to easily see their hearts pumping red blood throughout their bodies. But scientists have long been fascinated by the way the frogs' bellies turn transparent when they fall asleep, rendering them all but invisible to predators.

Related: Why is the color blue so rare in nature?

To better understand this phenomenon, Johnsen and colleagues tracked the red blood cells circulating throughout glassfrogs' bodies. One of these methods, known as photoacoustic microscopy, is not unlike ringing a bell with a laser beam — scientists shine a bright light onto the frog's body and capture the sound waves produced whenever the light strikes hemoglobin, the protein in red blood cells that carries oxygen and gives blood its distinctive color. 

"Even with a transparent animal, seeing exactly what is going on inside can be difficult," Johnsen said. "We used sound, because it travels through tissue much better than light."

Once they had developed this technique, studying how glassfrogs turn transparent was a simple matter of repeatedly agitating the hapless amphibians. "We'd let the frog rest, then poke it a few times, and let it fall asleep again." Johnsen said. Following the hemoglobin revealed that glassfrogs pull 89% of their red blood cells from circulation and stash them in their livers. Since their skin reflects very little light and their blood, sans hemoglobin, does not absorb it, they become almost entirely transparent.

Johnsen and colleagues hope that further study of this phenomenon will shed light on human clotting disorders and inform research into anticoagulants.

"The human body is always at this sharp edge between clotting too little and too much, whether we're talking about the big clots in strokes, which cause terrible damage, or little micro-clots at the periphery, which cause so much misery," Johnsen said. "The clotting process for frogs is not so different from that of humans, so whatever we learn from the frogs could end up being relevant to human clotting."

But so much about this process, including how they survive with so little hemoglobin circulating while they sleep, remains unclear. So before glassfrogs can inform clinical research, Johnsen and colleagues will need to figure out just how the amphibians are manipulating their blood. 

"What these frogs are doing is the equivalent of a human taking all their blood and stuffing it into a lunch bag inside their body," Johnsen said. "How are glassfrogs doing that? The cool thing is that we just don't know."

Only female wasps carry the equipment necessary to sting predators and inject them with toxins. It's therefore widely thought that male wasps are completely defenseless — but now, a study shows how some male wasps can escape certain death using nonvenomous but extremely spiky genitalia. 

Two thin, retractable "genital spines" lie on either side of the male mason wasp's (Anterhynchium gibbifrons) phallus. Some wasps use such spines to hold females in place during mating, but male mason wasps don't appear to do so, at least not in laboratory settings, according to a new study published Monday (Dec. 19) in the journal Current Biology. Instead, the wasps brandish their spiky phalluses only when confronted with a perceived predator — like the hand of a human scientist.

Study co-author Misaki Tsujii, a student in the Graduate School of Agricultural Science at Kobe University in Japan, was studying the life cycle of mason wasps when she felt a sudden "pricking pain" in her finger. She'd been handling a male wasp, which she'd believed to be harmless, and was surprised at the sensation, she told Live Science in an email.

Tsujii and her coauthor Shinji Sugiura, an associate professor in Kobe University's Graduate School of Agricultural Science, designed an experiment to see if the wasps could use their genitals to fend off predators they might encounter in the wild. They brought Japanese tree frogs (Dryophytes japonica) into the lab, placed them in containers with male mason wasps, set up cameras and waited.

Related: Cannibal wasp babies eat their siblings, because nature is brutal 

When the tree frogs hinged open their mouths to gobble up the wasps, the insects responded by snapping at the frogs with their mandibles and stabbing the frogs with their genital spines. Most of the wasps' defensive efforts were in vain, however, as nearly 65% of the insects were ultimately eaten. But in 35.3% of cases, the tree frogs spat out the struggling wasps and let them be. 

The team repeated this experiment with male wasps whose genitals had been removed and found that all the genitalia-less insects were quickly swallowed, although the wasps continued to bite at the frogs with their mandibles. 

"Therefore, genital spines of male genitalia appear to play a role in preventing tree frogs from swallowing male wasps," the authors wrote. 

The effectiveness of the males' genital spines pales in comparison to female wasps' true stingers, the team found. For starters, tree frogs were about half as likely to attempt to eat the female wasps in the first place, and when they did attack, they spat out the females about 87.5% of the time.

The scientists also exposed both male and female mason wasps to a second predator, the black-spotted pond frog (Pelophylax nigromaculatus). However, this frog was impervious to both the male's and female's defenses and quickly gobbled them up. 

"Pond frogs may have a high sting tolerance," Sugiura told Live Science in an email. "A previous study reported that a pond frog could eat even a venomous hornet." In addition, pond frogs live on the ground and encounter mason wasps less frequently than tree frogs do, as the wasps' favorite flowers grow on tree-climbing vines. So mason wasps may not be under strong pressure to evolve defenses that work against pond frogs.

The authors suspect that many other male wasps with "pseudo-stings" on their genitalia use the spikes for self-defense, Sugiura said. This hypothesis isn't new — it can be found in the Encyclopedia of Insects (Academic Press, 2009) — but it hasn't been formally tested in experiments with different wasp species, the team noted in their report.

Near-black frogs far outnumber their highlighter-yellow fellows in Chernobyl's radiation-blasted ecosystems, in a direct example of "evolution in action," a new study shows. The study, published Aug. 29 in the journal Evolutionary Applications, found that eastern tree frogs (Hyla orientalis) with more skin-darkening melanin pigment were more likely to survive the 1986 nuclear accident in Ukraine than frogs with lighter skin, leading to populations today that are dominated by darker frogs.

"Radiation can damage the genetic material of living organisms and generate undesirable mutations," researchers wrote in a post on The Conversation about their research. "However, one of the most interesting research topics in Chernobyl is trying to detect if some species are actually adapting to live with radiation. As with other pollutants, radiation could be a very strong selective factor, favoring organisms with mechanisms that increase their survival in areas contaminated with radioactive substances."

On April 26, 1986, a reactor at the Chernobyl nuclear power plant in Ukraine exploded, spewing radioactive materials across an 18-mile (30 kilometers) radius. 

"The Chernobyl accident released approximately 100 times the energy released by the nuclear bombs of Hiroshima and Nagasaki," Pablo Burraco, the study's lead author and a biologist with the Doñana Biological Station in Seville, Spain, told Live Science in an email.

Related: Frogs' skulls are more bizarre (and beautiful) than you ever imagined

Officials evacuated residents from the contaminated zone following the disaster and established a 1,040 square-mile (2,700 square kilometers) exclusion zone. In the decades since, the abandoned area has become a wildlife refuge. Burraco and his team wanted to understand how the nuclear meltdown drove evolution in the animals living there.

After studying more than 200 male frogs whose habitats were spread across 12 different breeding ponds throughout the radioactive contamination zone, researchers found that "on average, 44% were darker than those outside of Chernobyl," Burraco said. "We consider the most plausible explanation to [why] frogs within the Chernobyl Exclusion Zone [are changing color] is that the extremely high radiation levels at the moment of the accident selected for frogs with dark skin."

Why dark skin? It turns out that high melanin levels in frogs’ skin shielded them from radiation. 

"Melanin is known to protect against radiation because it can mechanically avoid the production of free radicals caused by the direct impact of the radioactive particles on cells," Burraco said. "Radiation can induce oxidative stress and damage essential structures for life such as the membrane of cells or even DNA."

Cells in the lighter frogs were bombarded with higher levels of damaging radiation, which killed them off at higher rates than their darker counterparts. After the blast, dark frogs had a higher likelihood of surviving, the study concluded. 

Researchers also looked for potential negative effects of excess melanin on the post-Chernobyl dark frogs. They found that like in other species, including certain types of fungi, having darker pigmented skin didn't harm the overall health of the amphibians and actually helped ionize radiation, which prevents ionized molecules from getting into cells and damaging them.

"The production of melanin can be metabolically costly, this has been described, for example, in several bird species," Burraco said. "However, in frogs, the main melanin pigment is called eumelanin and its production seems not to incur in physiological costs."

Frogs and toads make up the largest group of amphibians. Species in this order, called Anura, substantially outnumber those in the two other living orders of amphibians — Caudata (salamanders) and Gymnophiona (caecilians). As of August 2022, Anura had 7,486 of the 8,478 known amphibian species, according to Amphibian Species of the World, a reference website from the American Museum of Natural History in New York. 

Frogs and toads are among the most diverse animal groups. Though they might be most famous for their croaking and jumping, these animals have a wide variety of unique traits and behaviors. Like many other animals, frogs and toads are suffering greatly from human-related threats, and many species face imminent extinction. 

Frogs vs. toads

"Frog" and "toad" are common names that don't mean much from a scientific perspective. "Frog" can be thought of as the more encompassing word as it's the common name for the Anura order, and used in the common names of most of Anura's species. "Toad" is used more selectively in the common names of certain species or groups.

Amphibians with "toad" in their common names often have characteristics that are not typically thought of as frog-like. For example, "toads" usually live in drier habitats — and have drier, bumpier skin and shorter hindlimbs — than is typical for frogs, according to the Burke Museum in Seattle. However, all toads can be called frogs. 

Related: What's the difference between a frog and a toad?

Types of frog

Frogs come in a variety of shapes, colors and sizes. The largest frogs are Goliath frogs (Conraua goliath) from Cameroon and Equatorial Guinea; they can grow to be more than 1.1 feet (34 centimeters) long and weigh 7.3 pounds (3.3 kilograms), according to a 2019 study published in the Journal of Natural History. Goliath frogs appear to use their great size to shift rocks weighing more than 4 pounds (2 kg) to build "nursery ponds" that they clean and guard, Live Science previously reported. 

The world's smallest known frog is a tiny species called Paedophryne amauensis from Papua New Guinea. Described in a 2012 study published in the journal PLOS One, this frog grows to an average length of 0.3 inch (7.7 millimeters), making it the smallest known vertebrate on Earth, Live Science previously reported. 

Frogs are famed for their fantastic jumping skills, but not all frogs hop. Waxy monkey tree frogs (Phyllomedusa sauvagii) walk along branches, gripping them like monkeys do. These South American frogs secrete a natural opioid called dermorphin, which is many times stronger than morphine and has been used to create an illegal performance-enhancing drug for racing horses, according to the World Wildlife Fund. 

Many frogs utilize camouflage, whether it's to stay hidden from predators or blend into their environment so prey don't notice them. For example, Vietnamese mossy frogs (Theloderma corticale) from Vietnam resemble clumps of moss. Poison dart frogs are called the "jewels of the rainforest" because they come in various colors that warn predators they're toxic and shouldn't be eaten. However, even these bright colors can act as camouflage in a vibrant rainforest. 

Glass frogs have translucent green skin that makes their internal organs, and even beating hearts, visible to the human eye. They've evolved for predators to look straight through them. A 2020 study published in the journal Proceedings of the National Academy of Sciences (PNAS) found that these frogs aren't truly transparent, but their camouflage is flexible.

"The frogs are always green but appear to brighten and darken depending on the background," lead author James Barnett, a behavioral ecologist at McMaster University in Ontario, said in a statement at the time. "This change in brightness makes the frogs a closer match to their immediate surroundings, which are predominantly made up of green leaves."

While there are thousands of known frog species, there are likely many more that scientists haven't found yet. For example, researchers described six new species from Mexico in April 2022, and each can fit comfortably on a thumbnail. The researchers noted at the time that the frogs could represent the tip of a giant iceberg of unknown amphibians just in Mexico, Live Science previously reported.  

Related: Adorable 'chocolate frog' discovered in crocodile-infested swamp

Where do frogs live?

Frogs are found on every continent except Antarctica. They need to be around water sources to reproduce, but their habitats are extremely varied otherwise. Poison dart frogs hop through the tropical rainforests of Central and South America, while northern leopard frogs (Lithobates pipiens) inhabit much of North America's marshlands, brushlands and other habitats, including farmland and golf courses, according to the University of Michigan's BioKids website. 

Some species live in highly specialized environments. For example, Vietnamese mossy frogs live in mossy, flooded caves and the banks of rocky mountain streams around 2,300 to 3,300 feet (700 to 1,000 meters) above sea level, according to the Smithsonian's National Zoo & Conservation Biology Institute in Washington, D.C. Meanwhile, desert rain frogs (Breviceps macrops) appear to live exclusively in the white sand dunes of Namibia and South Africa, burrowing into the sand during the day and feeding at night, according to the International Union for Conservation of Nature (IUCN). 

Frogs have lungs, but they can also breathe through their skin by absorbing oxygen from water. They can still drown if their lungs fill with water or there's not enough oxygen in the water they're swimming in, according to the Burke Museum. 

What do frogs eat?

Frogs have a wide diet that includes insects, spiders, worms, slugs, larvae and small fish. These amphibians play a vital role in the world's ecosystems by helping to keep insect populations under control, according to the San Diego Zoo. They catch prey using their quick, sticky tongues. A 2017 study published in the Journal of the Royal Society Interface found that frog tongues can catch insects in 0.07 second — five times faster than the blink of a human eye. 

Related: Watch this frog light up after it swallows a firefly

Some frogs seek out much larger prey than flies and slugs. For example, cane toads (Rhinella marina), which typically grow to 9 inches (23 cm) in length, scarf down small birds, mammals and snakes with ease, as well as other amphibians and even table scraps and pet food, according to the Florida Fish and Wildlife Conservation Commission. Their native range stretches from the Amazon basin in South America up to southern Texas. But humans have introduced cane toads elsewhere, and their insatiable appetites can be a big problem for wildlife. They are an invasive species in areas such as Florida and Australia, where they compete with native amphibians and poison animals that try to feed on them, including pets and, in Australia's case, endangered species such as Tasmanian devils (​​Sarcophilus harrisii), according to the San Diego Zoo.

How do frogs reproduce?

Frogs have many mating strategies, and scientists are still learning about these animals' sex lives. For most species, mature males initiate the breeding process by calling loudly to tell females they are ready to mate, according to the Australian Museum in Sydney. Females filled with eggs approach calling males and choose one to mate with, usually in water. Fertilized eggs, or frog spawn, can incubate for anywhere between 48 hours and 23 days before hatching, depending on the species, according to the San Diego Zoo. Small, legless, fish-like tadpoles emerge from the eggs and begin life feeding on algae.  

Tadpoles' transformation into mature frogs starts with the release of hormones from their thyroid glands, according to the book "Developmental Biology" (Sinauer Associates, 2000). Over time, tadpoles grow legs, lose their tails and emerge from the water capable of living on land. The word "amphibian" comes from the Greek words "amphi" and "bios," which translate to "both life," because they live in water and on land, according to the Oxford Learner's Dictionaries.  

Related: 'Ancient death trap' preserved hundreds of fossilized frogs that drowned during sex

Do frogs hibernate?

Frogs are ectothermic, or "cold-blooded," like other amphibians, reptiles and snakes. This means they can't regulate their own body temperature internally like mammals do, and they rely on the external environment to stay warm, according to Froglife, a conservation charity based in the U.K. To survive winter in colder environments, frogs may go into a state of dormancy, called brumation, underwater or under log piles. Brumation is similar to hibernation, except frogs may occasionally emerge from their dormant state to eat. 

Wood frogs (Lithobates sylvaticus) have an even more extreme winter survival strategy to survive in the northern forests of Alaska and Canada: They allow ice to fill their abdominal cavities and encase their internal organs. In this state, wood frogs' hearts stop beating and they appear to be frozen solid, but they're still alive in a state of suspended animation. The frogs survive because their livers produce glucose that prevents their cells from freezing. They begin to thaw out in spring, and at some point — though scientists aren't sure how — their hearts start beating again and they go on their way, according to the National Park Service. 

Are frogs poisonous?

The bumps on amphibians' skin aren't warts, and people can't contract warts from handling these animals. The myth that people can get warts from frogs likely stems from the wart-like appearance of the bumps, according to the Burke Museum. However, many frogs produce poisonous secretions that can irritate human skin or cause serious harm if ingested. For example, the most toxic poison dart frogs in the genus Phyllobates produce batrachotoxin, which disrupts the human body's nervous system and can cause paralysis, extreme pain and heart failure. As well as potential toxins, frogs can carry bacteria and parasites, according to the Burke Museum. 

The secretions of frogs have played an important role in the development of human medicine; they're used, for example, to make painkillers and antibiotics. Furthermore, around 10% of physiology and medicine Nobel Prize winners used frogs as part of their research, according to Save the Frogs, an amphibian conservation charity based in California.

A few frogs are venomous as well as poisonous. Poison is harmful if ingested, but animals are venomous if they inject their toxins. A 2015 study published in the journal Current Biology found that two Brazilian frog species possessed bony spines on their skulls that they could use like venomous fangs. These frogs, called Bruno's casque-headed frogs (Aparasphenodon brunoi) and Greening's frogs (Corythomantis greeningi), headbutt potential predators to stab them with the spines and transfer toxins, according to the Natural History Museum in London.

Related: Frogs' skulls are more bizarre (and beautiful) than you ever imagined

Are frogs endangered?

Amphibians are the most threatened group of vertebrates on Earth; 40% of the amphibian species assessed by the IUCN are at risk of extinction. This means that many frog species are declining and need help from humans if they are to survive. According to the IUCN SSC Amphibian Specialist Group, some of the main threats facing amphibians are habitat loss and degradation, pollution, disease, invasive species, trade and climate change. 

Frog extinction has disturbing implications for humans. The amphibians are highly susceptible to environmental disturbances, making frog populations a good indicator of the health of an environment, according to Save the Frogs. Therefore, the sheer number of amphibians at risk of extinction can be viewed as a wake-up call for the environmental damage that humans are causing to the planet. 

Additional resources

For more information about how venomous frogs headbutt potential predators, watch this short YouTube video from the Natural History Museum in London. For tips on how to help your local frogs, check out the National Wildlife Federation website. To learn more about different frog species, check out "Frogs and Toads of the World" (Princeton University Press, 2011). 

This article was originally written by Live Science contributor Alina Bradford and has since been updated.

A bizarre, newly discovered species of ancient salamander recently received a digital makeover. Researchers used X-ray images to create a 3D model of the animal's oddly shaped skull, which had been trapped inside a Jurassic rock first uncovered around 50 years ago.  

The newly identified species, which scientists named Mamorerpeton wakei, dates to around 166 million years ago, during the Jurassic period (201.3 million to 145 million years ago). Researchers estimated that these ancient salamanders grew to be around 6.3 inches (16 centimeters) long, and the shape and structure of their bones suggested they were an aquatic species that likely swam around ancient ponds or lakes, slurping up smaller creatures with powerful suction. 

Part of the ancient amphibian was collected unintentionally in the early 1970s, by another group of researchers on Scotland's Isle of Skye. This team had unearthed a lump of limestone with a single bone protruding from the surface, suggesting that there might be something of interest inside. However, the limestone block was deemed less important than other fossils that were collected at the time, and the limestone — along with its undetermined contents — went into storage. However, another research team uncovered additional fragments of the specimen between 2016 and 2019, suggesting that the long-ignored rock in storage might contain part of the unknown creature's skull.

For the new study, the authors used X-rays to scan the skull block without damaging any of the fragile bones inside. The team generated around 800 individual projections, or images, of the bones inside the block and then used a computer program to reassemble the skull, which had been crushed and mangled inside the rocky matrix, back into its original 3D shape.

Related: 10 coolest non-dinosaur fossils unearthed in 2021 

"Initially, we thought the material would represent Mamorerpeton kermacki," an ancient salamander species known from rocks of the same time period in England, lead study author Marc Jones, an evolutionary biologist at University College London, told Live Science in an email. However, the skull reconstruction revealed that it was actually a new species from the same genus, Jones added.  

The researchers were surprised to discover just how dramatically the skull differed from those of salamanders alive today.

"There is a lot of variation in skull structure among modern salamanders," Jones said. "But the new fossil salamander is different from all of them." Some of the bones resembled those seen in frogs, and a couple of standout features were crocodile-like structures on the roof of the skull and bony projections behind the eye, both of which are unlike anything seen in modern salamanders. Attachment of the jaw muscles also differed from the jaws of most modern salamanders.

The unusual characteristics of the skull, combined with its salamander-like structures, suggest that M. wakei may have been an evolutionary cousin of many modern salamanders, of which there are around 750 species, according to the study. Previously, other researchers had identified ancient salamanders from the genus Karaurus as the most likely common ancestors of modern salamanders, Jones said. M. wakei and Karaurus show lots of similarities, which hinted that the new species may also be a common ancestor of modern salamanders. But comparisons to a broad sample of amphibians show that neither are the common ancestor of modern salamanders. Instead, these species represent an evolutionary side branch, Jones said. The new discovery shows that salamander evolution is "more complicated than previously assumed," he added. 

The researchers said the discovery highlights the importance of assessing all fossil discoveries — even those that initially seem unremarkable. It is "common" for fossils like this to slip under the radar because it can be expensive and time-consuming to analyze them, Jones said. But as technology continues to advance, long-ignored fossils like this one can provide new insight into the evolution of modern creatures, which is "important for understanding why they are the way they are," he added.

The study was published online July 11 in the journal Proceedings of the National Academy of Sciences.

Originally published on Live Science.

It was a cold case with hundreds of victims. For decades, scientists puzzled over a gruesome mystery: What killed hundreds of fossilized frogs found at an ancient "death trap" in Germany dating to millions of years ago? These frogs seemed to be completely healthy when they died, but researchers recently determined that the amphibians may have drowned during aggressive underwater sex. 

For the new study, scientists analyzed the remains of 168 frogs found at an old mining site in the Geiseltal valley, in central Germany's Saxony-Anhalt region. The specimens were originally collected between the 1930s and 1950s, along with around 50,000 other fossils. Around half of those were vertebrates, and included horse ancestors, large crocodiles, giant snakes and ground-dwelling birds, researchers said in a statement.

The fossilized frog bones date back to around 45 million years ago during the Eocene epoch; at the time, the site was a coastal swamp bordering the Palaeo-North Sea, which covered most of northern Germany. Chemical conditions within the swamp delayed the decay of dead organisms until they could be fossilized by minerals in the water, which preserved the paleontological "treasure trove" of specimens, according to the statement. 

Analysis of the bones revealed that the frogs weren't killed by predators or disease. Through the process of elimination, the scientists concluded that the most likely cause of death was mating, as male frogs in species alive today are known to sometimes hold females under the water as they mount them, causing the females to drown. "By studying the bones of the fossil frogs we were able to narrow down the options of death," lead study author Daniel Falk, a paleontologist at University College Cork in Ireland, told Live Science in an email. "The only explanation that makes sense is that they died during mating."

Related: Lost fossil 'treasure trove' rediscovered after 70 years 

Other paleontologists had previously proposed that the frogs died due to extreme environmental changes such as flooding or drought. Another hypothesis suggested that the culprit was sudden oxygen depletion in the water, which would have affected the amphibians' ability to absorb oxygen through their skin, known as cutaneous respiration, and led to mass drownings. 

However, the frog's bones showed evidence that the corpses floated after the animals died, which ruled out swamp desiccation, Falk said. "Frogs and toads will also migrate if water conditions in their pond are not suitable," which probably rules out oxygen depletion, he added. "There’s also no evidence that they were washed in during floods."

Other causes of death, such as predation, disease, malnourishment or old age, would have left distinct signatures in the frog's remains, Falk said. This left mating as the most plausible cause of death for these fossilized frogs.

During mating, frog males mount females from behind and then climb on top of the female's backs. On land, this is not an issue for the females. But some species of frogs mate in water, which can force the females under the surface and drown them if the males take too long. This mating behavior is seen in some modern species of frogs — among certain species, it can be "very common," Falk said.

Drowning is more likely to happen when groups of males try to mate with a single female, forming what is known as a breeding ball, Falk said. "This often happens in species that engage in mating congregations during a short explosive breeding season," he explained. It's possible that this is what took place tens of millions of years ago with the Geiseltal frogs, who may have migrated to the swamps once a year for mass breeding, he added.

However, researchers were unable to determine the gender of the frogs from just their bones, so there is no way to determine if the fossilized frogs are all female, Falk said. This makes it impossible to definitively prove their hypothesis. 

Several other sites around the world that date to different time periods also preserve fossils from seemingly healthy frogs in which the causes of death are uncertain. The team suspect that frogs at these sites may also have drowned during sex, which hints the phenomenon is far more prevalent in ancient frog populations than once thought. "This suggests that the mating behaviors of modern frogs are really quite ancient and have been in place for at least 45 million years," Falk said.

This poses another potential mystery: After millions of years of frog evolution have elapsed, why are females still drowning during sex? For species who still procreate this way, the benefits of mating in water must outweigh the costs — but it's unclear how. 

The researchers suspect that further study of how these fossilized frogs died could reveal clues about amphibian evolution and how amphibians have adjusted as their ecosystems changed over time. "If we understand how and why these frogs died so long ago, we can learn to protect not only modern frogs, but also learn how ecosystems evolve and how animals adapt in a variable environment," Falk said.

The study was published online July 5 in the journal Papers in Palaeontology.

Originally published on Live Science.

Six newly-described species of miniature frogs from Mexico and Guatemala are so tiny that each can fit comfortably on a human thumbnail. Two of the species are smaller than 0.7 inches (18 millimeters) long, and the tiniest of them — Craugastor candelariensis — is Mexico's smallest frog, measuring no more than 0.5 inches (13 mm) long.

The wee frogs live in moist leaf litter on forest floors and are known as direct-developing frogs, which means that they don't undergo a tadpole stage as part of their life cycle, the researchers who described the species wrote in a new study. Rather, the frogs hatch from eggs as miniature versions of their adult forms. 

Hatchlings are thought to measure less than than 0.4 inches (10 mm) long, but scientists aren't certain about that because no one has ever seen these frogs hatch, said lead study author Tom Jameson, a researcher in the Department of Zoology at the University of Cambridge in the United Kingdom, and a doctoral candidate in the Cambridge Climate, Life and Earth (C-CLEAR) program. 

"We know very little about their reproduction, life history, and behaviour," Jameson told Live Science in an email.

Related: Cannibal toads eat so many of their young, they're speeding up evolution

Other scientists had collected the frogs years ago and placed them in museum collections, cataloging the minuscule amphibians as undefined species in the Craugastor genus or as possibly belonging to the miniature frog species C. pygmaeus or C. hobartsmithii, the study authors reported April 4 in the journal Herpetological Monographs.

However, the diminutive frogs all looked so similar that scientists couldn't be sure exactly where the frogs fit on the Craugastor family tree. 

"We revisited this classification because one of my co-authors, Jeff Streicher [a senior curator of amphibians and reptiles at the Natural History Museum in London], did some genetic analysis back in 2012 and found a pattern that suggested multiple undescribed species," Jameson explained.

The researchers then followed up on Streicher's findings by conducting DNA analysis of the Craugastor specimens in question, and using computed X-ray tomography (CT) scans to create 3D digital models that highlighted differences in the shapes of frog bones and body parts. When their analysis was done, the scientists grouped the specimens into six new species: C. bitonium, C. candelariensis, C. cueyatl, C. polaclavus, C. portilloensis and C. rubinus.

"We found that each species was genetically distinct," Jameson said. "We also found differences in skull shape, level of ossification of the skeleton, and in external features like the number of tubercles [hardened bumps] on the hands and feet." 

Because the frogs are so small, they're on the menu for just about every predator in their woodland ecosystem, including birds, lizards, small mammals, and even large insects and other frogs, Jameson said. But the frogs face much greater risks from human activities, he added.

"The real threat to these frogs comes from habitat loss, climate change (further modifying habitats), and disease," such as the highly infectious fungal disease chytridiomycosis, or chytrid disease, Jameson wrote in the email. Chytrid disease is caused by the fungus Batrachochytrium dendrobatidis, which infects amphibians through their skin and is easily spread to new habitats by humans, according to the Cornell Wildlife Health Lab at Cornell University in Ithaca, New York.

Despite their small size, these frogs could represent the tip of a very big iceberg of unknown amphibian biodiversity in the region, the study authors reported. 

"We suspect that additional species await discovery, particularly in western Mexico and east of the Isthmus of Tehuantepec where our sampling efforts were limited," the authors wrote.

Originally published on Live Science.

Hearts have become iconic symbols of Valentine's Day, but when it comes to hearts in the real world, one size doesn't fit all — particularly in the animal kingdom. At rest, the human heart beats between 60 and 80 times a minute, but in that same time, a hibernating groundhog's heart beats just five times and a hummingbird's heart reaches 1,260 beats per minute during powered flight. The human heart weighs about 0.6 pounds (0.3 kilograms), but a giraffe's weighs about 25 pounds (11 kg), as the organ needs to be powerful enough to pump blood up the animal's long neck. Here are some other creatures with strange hearts. 

1. Frogs

Mammals and birds have four-chambered hearts, but frogs have just three, with two atria and one ventricle, said Daniel Mulcahy, a research collaborator of vertebrate zoology who specializes in amphibians and reptiles at the Smithsonian Institution, Museum of Natural History in Washington, D.C.

In general, the heart takes deoxygenated blood from the body, sends it to the lungs to get oxygen, and pumps it through the body to oxygenate the organs, he said. In humans, the four-chambered heart keeps oxygenated blood and deoxygenated blood in separate chambers. But in frogs, grooves called trabeculae keep the oxygenated blood separate from the deoxygenated blood in its one ventricle.

Frogs can get oxygen not only from their lungs, but also from their skin, Mulcahy said. The frog's heart takes advantage of this evolutionary quirk. As deoxygenated blood comes into the right atrium, it goes into the ventricle and out to the lungs and skin to get oxygen.

The oxygenated blood comes back to the heart through the left atrium, then into the ventricle and out to the major organs, Mulcahy said.

Even weirder are the hearts of freeze-tolerant frogs, including the wood frog (Lithobates/Rana sylvaticus), whose heart completely stops when the frog freezes during winter hibernation, and then starts beating again within one hour of thawing, according to a 1989 study in the American Journal of Physiology. 

2. Whales

The blue whale's heart is the largest of all the animals living today. "It is the size of a small car and has been weighed at about 950 pounds [430 kg]," said James Mead, a curator emeritus of marine mammals in the department of vertebrate zoology at the National Museum of Natural History at the Smithsonian Institution. Like other mammals, the whale's heart has four chambers.

The organ is responsible for supplying blood to an animal the length of two school buses, said Nikki Vollmer, an assistant scientist for the Cooperative Institute for Marine and Atmospheric Studies working with the NOAA Fisheries' Southeast. "The walls of the aorta, the main artery, can be as thick as an iPhone 6 Plus is long," or over 6 inches (15 centimeters), Vollmer told Live Science. "That is a thick-walled blood vessel!" 

When blue whales dive deep into the ocean, their heart rate slows to four beats per minute, which helps them extend their dive time and may even mitigate decompression sickness, known as the bends. That's because this lower heartbeat lowers the passage of blood into the pressurized lungs, and the in-hand reduction of nitrogen uptake may alleviate the bends, a 2021 study in the journal Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology reported.

3. Cephalopods

There's nothing half-hearted about cephalopods. These tentacular and armed marine creatures, including the octopus, squid and cuttlefish, have three hearts apiece.

Two brachial hearts on either side of the cephalopod's body oxygenate blood by pumping it through the blood vessels of the gills, and the systemic heart in the center of the body pumps oxygenated blood from the gills through the rest of the organism, said Michael Vecchione, an invertebrate zoologist at the Smithsonian's National Museum of Natural History.

Cephalopods are also literally blue-blooded because they have copper in their blood. Human blood is red because of the iron in hemoglobin. "Just like rust is red, the iron in our hemoglobin is red when it's oxygenated," Vecchione said. But in cephalopods, oxygenated blood turns blue. 

4. Cockroaches

Like other insects, the cockroach has an open circulatory system, meaning its blood doesn't fill blood vessels. Instead, the blood flows through a single structure with 12 to 13 chambers, said Don Moore III, a senior scientist at the Smithsonian's National Zoo in Washington, D.C.

The dorsal sinus, located on the top of the cockroach, helps to send oxygenated blood to each chamber of the heart. But the heart isn't there to move around oxygenated blood, Moore said.

"Roaches and other insects breathe through spiracles [surface openings] in the bodies instead of lungs, so the blood doesn't need to carry oxygen from one place to another," Moore said.

Instead, the blood, called hemolymph, carries nutrients and is white or yellow, he said. The heart doesn't beat by itself, either. Muscles in the cavity expand and contract to help the heart send hemolymph to the rest of the body.

The heart is often smaller in wingless cockroaches than in flying ones, Moore said. The cockroach's heart beats at about the same rate as a human heart, he added. 

5. Earthworms

The earthworm can't take heart, because it doesn't have one. Instead, the worm has five pseudohearts that wrap around its esophagus. These pseudohearts don't pump blood, but rather they squeeze vessels to help circulate blood throughout the worm's body, Moore said.

It also doesn't have lungs, but absorbs oxygen through its moist skin."Air trapped in the soil, or aboveground after a rain when worms can stay moist, dissolves in the skin mucus, and the oxygen is drawn into the cells and blood system where it is pumped around the body," Moore said.

Earthworms have red blood that contains hemoglobin, the protein that carries oxygen, but unlike people worms have an open circulatory system. "So the hemoglobin just kind of floats among the rest of the fluids," Moore said. 

6. Fish

If a zebrafish has a broken heart, it can simply regrow one. A study published in 2002 in the journal Science found that zebrafish can fully regenerate heart muscle just two months after 20% of their heart muscle is damaged.

Humans can regenerate their liver, amphibians and some lizards can regenerate their tails, and frogs given a special drug cocktail even regrew legs in a 2022 study in the journal Science Advances, but the zebrafish's regenerative abilities make it a prime model to study heart growth, Moore said. 

However, fish have unique hearts. In addition to the one atrium and one ventricle, fish also have two structures that aren't seen in humans. The "sinus venosus" is a sac that sits ahead of the atrium and the "bulbus arteriosus" is a tube located just behind the ventricle.

As in other animals, the heart drives blood throughout the body. Deoxygenated blood enters the sinus venosus and flows into the atrium, Moore said. The atrium then pumps the blood into the ventricle.

The ventricle has thicker, more muscular walls, and pumps the blood into the bulbus arteriosus. The bulbus arteriosus regulates the pressure of the blood as it flows through the capillaries surrounding the fish's gills. It is in the gills where there is oxygen exchange across cell membranes and into the blood, Moore said.

But why does the fish need the bulbus arteriosus to regulate blood pressure?

"Because the gills are delicate and thin-walled — any fisherman knows this — and can be damaged if the blood pressure is too high," Moore said. "The bulbus arteriosus itself is apparently a chamber with very elastic components compared to the muscular nature of the ventricle." 

Editor's note: Originally published on Feb. 13, 2015 and updated on Feb. 14, 2022.

Originally published on Live Science.

Scientists have regrown frogs' amputated legs after giving them a "cocktail" of drugs encased in a silicon stump. 

African clawed frogs (Xenopus laevis) are like humans in that they can't naturally regrow lost limbs. In the new study, researchers successfully coaxed the frogs to grow replacement limbs in 18 months following a treatment that lasted just 24 hours. While there's a massive difference between frogs and humans, the finding raises the possibility that in the future, humans could also regrow limbs.

"It's exciting to see that the drugs we selected were helping to create an almost complete limb," first author Nirosha Murugan, a research affiliate at Tufts University in Massachusetts, said in a statement. "The fact that it required only a brief exposure to the drugs to set in motion a months-long regeneration process suggests that frogs and perhaps other animals may have dormant regenerative capabilities that can be triggered into action."

Related: 13 extremely strange animal feet

Animals have natural abilities to regenerate themselves. For example, human bodies close open wounds and can even use stem cells to regrow parts of the liver. Some animals, such as salamanders, can regrow whole limbs and other missing parts. The mechanisms behind limb regeneration are not fully understood, but neither humans nor adult frogs are capable of regrowing legs and arms, perhaps because those limbs are so complex. 

Both humans and frogs cover an open amputation wound in scar tissue to stop further blood loss and infection. Humans have developed prosthetic replacement limbs but scientists have been unable to recover or reverse the loss of a major limb like an arm or leg. 

The latest research used multiple drugs to regenerate lost limb tissue. The team surgically amputated frogs' legs and then applied a silicone cap they called a "BioDome" to each frog's wound. The cap released a cocktail of five drugs, including growth hormones, that perfomed different roles, such as encouraging nerves and muscles to grow. One of the drugs also prevented the frogs' bodies from producing collagen, which normally causes wounds to scar over.

"Using the BioDome cap in the first 24 hours helps mimic an amniotic-like environment, which, along with the right drugs, allows the rebuilding process to proceed without the interference of scar tissue," co-author David Kaplan, a professor of engineering at Tufts University, said in the statement. 

Embryos and fetuses develop in an amniotic sac during pregnancy. The team was able to trigger some of the same molecular pathways in the frogs that are used when an embryo is growing and taking shape. 

The new legs looked similar to normal legs with similar bone structure, except for the toes, which lacked underlying bones. The frogs were able to use their new leg to swim like a regular leg. 

The findings were published Jan. 26 in the journal Science Advances. 

Originally published on Live Science.

Poison dart frogs are small, brightly colored amphibians that live on tropical rainforest floors across Central and South America. They are members of the family Dendrobatidae, and there are more than 175 known species, according to San Francisco Zoo. Poison dart frogs are tiny, measuring  just 1 to 2 inches (2.5 to 5 centimeters) long, and unlike many other amphibians they are diurnal, meaning they are active in the daytime, according to the Rainforest Alliance.

Poison dart frogs are named for the toxins they secrete from their skin, which have traditionally been used to tips of hunters' weapons. For example, the Emberá and Noanamá Indigenous people in western Colombia have used the skin of golden poison frogs (Phyllobates terribilis) to tip blowgun darts for hundreds of years, according to the American Museum of Natural History. 

Poison dart frogs come in a range of vivid colors, and so they are sometimes known as the "jewels of the rainforest." Their vibrant coloring warns predators that the frogs are poisonous and should be avoided. This survival mechanism is called aposematism. Some species of poison dart frogs also use their colors and patterns as camouflage. For example, dyeing dart frogs (Dendrobates tinctorius) use their bright-yellow and black patterns to blend in with their natural habitat when viewed from a distance, according to research published in 2018 the journal Proceedings of the National Academy of Sciences (PNAS).

Related: Adorable 'chocolate frog' discovered in crocodile-infested swamp

The huge variety of colors among poison dart frog species may be a result of the frogs’ ancestors becoming separated around 10,000 years ago, when what is now Panama flooded, isolating the frogs in different locations. The various frog populations then evolved their own colorization, according to the Smithsonian Institute.

How poisonous are poison dart frogs?

Poison dart frogs’ toxicity differs between species. The most toxic species of poison dart frogs belong to the genus Phyllobates. These frogs secrete a potent toxin called batrachotoxin, according to the Encyclopedia of Toxicology. Golden dart frogs are considered one of the most toxic animals on Earth, according to National Geographic.

Batrachotoxin is a powerful steroidal alkaloid that interferes with the  body’s nervous system. The brain sends instructive electrical messages to different parts of the body that pass through sodium channels. Batrachotoxins keep these channels open and disrupt the brain's messaging system, causing several debilitating and potentially fatal conditions, such as paralysis, extreme pain and even cardiac failure. 

There is, however, one animal that can withstand the poisonous powers of golden dart frogs: fire-bellied snakes (Liophis epinephelus). These snakes are the only known natural predators of dart frogs because they are immune to the frogs’ toxins, according to the Animal Diversity Web. 

Poison dart frogs have also developed techniques to avoid poisoning themselves. A study published in the Journal of General Physiology proposed that poison dart frogs have "toxin sponge" molecules that prevent the batrachotoxin from binding with sites on the frogs’ own cells, providing them with immunity to their own poison. 

Related: Why don't poisonous animals die from their own toxins?

What do poison dart frogs eat?

As tadpoles (the stage before the animals reach adulthood), their diet consists of whatever is available to them, such as algae, dead insects and in some cases other tadpoles. Adult poison dart frogs are omnivores, but they predominantly feast on insects such as ants, termites and beetles, according to the San Diego Zoo Wildlife Alliance. 

Poison dart frogs obtain their toxicity through their diet. Although it remains largely unknown which insects are responsible for giving these frogs their poisonous powers, a study published in the journal PNAS proposed that melyrid beetles (genus Choresine) might be the culprits. 

Related: Photos: The poisonous creatures of the North American deserts

These beetles contain high levels of batrachotoxin and have been found in the bellies of pitohui birds — which produce the same secreted poison as poison dart frogs. "The family Melyridae is cosmopolitan, and relatives in Colombian rainforests of South America could be the source of the batrachotoxins found in the highly toxic Phyllobates frogs of that region," the study researchers wrote. 

Wild poison dart frogs that are put into captivity lose the majority of their toxicity, whereas frogs born and raised in captivity don't develop the toxins at all. This is due to the difference between a wild and captive diet, according to the San Diego Zoo Wildlife Alliance. 

What is the life cycle of a poison dart frog?

Mating occurs throughout the year but particularly during the rainy seasons, at a site on the forest floor chosen by the male. To mate, the female deposits the unfertilized eggs on leaf-litter in a dark and moist environment, and the male releases his sperm onto the eggs to fertilize them. A frog's clutch can vary in size, but some species produce as many as 40 eggs at a time, according to the Smithsonian's National Zoo & Conservation Biology Institute. 

The parent frogs guard their unborn offspring for between 10 and 18 days, occasionally watering them with their urine. The eggs hatch into tadpoles, which latch onto their mother's back, and she then carries them to a pool of water. The pool becomes a nursery for the tadpoles for the next few months, until they undergo metamorphosis and become adult frogs, according to the Smithsonian. 

A study published in the journal Symbiosis suggests that bromeliad plants also benefit from having tadpoles between their leaves. Researchers proposed that the plants benefit from absorbing the nitrogen that is produced from the tadpoles feces and which acts as a fertilizer. 

Adult poison dart frogs vary in size between species and can range between 0.75 and 1.5 inches (20 to 40 millimeters) in length, according to the Smithsonian. Females tend to be larger than males, and males can also be distinguished from females by their larger front toe pads in some species — such as blue poison dart frogs (Dendrobates azureus) according to Peoria Zoo in Illinois. 

The age these amphibians reach sexual maturity also differs between species. For example, strawberry poison dart frogs (Oophaga pumilio) reach maturity after ten months of adulthood, according to the Animal Diversity Web, whereas blue poison dart frogs take two years before they’re ready to mate, according to Toronto Zoo. The average lifespan of a poison dart frog is between three and 15 years, according to National Geographic. 

Additional resources

• Poison Dart Frogs (Pilot Books: Nature's Deadliest)
• Magnificent Book of Reptiles and Amphibians
• Aposematic Poison Frogs (Dendrobatidae) of the Andean Countries

Some of the most poisonous animals in the world are small, colorful frogs called poison dart frogs, in the family Dendrobatidae, which live in the rainforests of Central and South America. A single frog carries enough poison to kill 10 adult humans. Interestingly, these frogs aren't born poisonous — they acquire their poisonous chemical by eating insects and other arthropods. 

But if this poison is so deadly, why do the frogs themselves not die when they ingest it?

These frogs' ability to avoid autointoxication has puzzled scientists for a long time, said Fayal Abderemane-Ali, a researcher at the University of California San Francisco's Cardiovascular Research Institute, and the lead author of a new study in the Journal of General Physiology that explores this phenomenon. 

Related: What should you do if you're bitten by a venomous snake?

In the new paper, the researchers studied poison frogs in the genus Phyllobates that employ a toxin called batrachotoxin, which works by disrupting the transport of sodium ions in and out of cells — one of the most important physiological functions in the body. When your brain sends signals to the body, it sends them via electricity. These signals carry instructions to parts of the body, for example to your limbs to tell them to move, to muscles to tell them to contract, and to the heart to tell it to pump. These electrical signals are made possible by the flow of positively charged ions, such as sodium, into negatively charged cells. Ions flow in and out of cells via protein doors called ion channels. When these ion channels are disrupted, electrical signals can't travel through the body. 

Batrachotoxin causes the ion channels to stay open, resulting in a freely-flowing stream of positively charged ions into cells, Abderemane-Ali told Live Science. If those are unable to close, the entire system loses its ability to transmit electrical signals. 

"We need these channels to open and close to generate electricity that runs our brain or heart muscles," Abderemane-Ali said. If the channels just stay open, "there is no cardiac activity, there is no neuronal activity or contractive activity."

Basically, if you ingest one of these frogs, you die — almost immediately. 

So how do these frogs, and other poisonous animals, avoid suffering the same fate? There are three strategies poisonous animals use to stop autointoxication, Abderemane-Ali said. The most common involves a genetic mutation that slightly changes the shape of the toxin's target protein — the sodium-ion door — so that it can no longer bind to the protein. For example, a species of poison frog called Dendrobates tinctorius azureus carries a toxin called epibatidine that mimics a beneficial signaling chemical called acetylcholine. According to a 2017 study published in the journal Science, these frogs evolved adaptations in their acetylcholine receptors that slightly changed the shape of those receptors, making them resistant to the toxin. 

Another strategy, used by predators of poisonous animals, is the ability to get rid of the toxin from the body entirely, Abderemane-Ali said. This process isn't necessarily the same as avoiding autointoxication, it's just another way that animals avoid being poisoned by things they eat.

The third strategy is called "sequestration."

"The animal will develop systems to capture [or] to soak up the toxin to make sure that it does not cause problems to the animal," Adberemane-Ali said.

In Adberemane-Ali's study, he cloned sodium-ion channels from Phyllobates frogs and treated them with the toxin. He was surprised to see that the sodium-ion channels were not resistant to the toxin. 

"These animals should be dead," Abderemane-Ali said. Because the frogs' sodium-ion channels did not resist the toxin's disruptive effects, the frogs shouldn't be able to survive with this toxin in their bodies.

Based on those results, Abderemane-Ali suspects that these frogs are most likely employing the sequestration strategy of avoiding autointoxication by using something he calls a "protein sponge." The frogs likely produce a protein that can sop up the toxin and hold onto it, meaning the toxin never has a chance to reach those vulnerable protein channels in the first place.

American bullfrogs (Rana catesbeiana) also use sequestration, Abderemane-Ali said. These frogs produce a protein called saxiphilin, which can bind to and block the toxin saxitoxin. Saxiphilin is currently being studied as a potential solution to neutralize toxins introduced into our water supply by harmful algal blooms.

Originally published on Live Science.

For knife-toothed kukri snakes, the tastiest parts of a frog are its organs, preferably sliced out of the body cavity and eaten while the frog is still alive. After observing this grisly habit for the first time in Thailand, scientists have spotted two more kukri snake species that feast on the organs of living frogs and toads.

The new (and gory) observations suggested that this behavior is more widespread in this snake group than expected. Two snakes also eventually swallowed their prey whole, raising new questions about why they would extract the living animals' organs first.

The scientists documented a Taiwanese kukri snake (Oligodon formosanus) and an ocellated kukri snake (Oligodon ocellatus) pursuing amphibian organ meals, tearing open frogs' and toads' abdomens and burying their heads inside, according to the studies. O. formosanus would even perform "death rolls" while clutching its prey, perhaps to shake the organs loose. As the snakes swallowed the organs one by one, the amphibians were still alive. Sometimes, the process would take hours, the researchers reported.

Related: Beastly feasts: Amazing photos of animals and their prey

There are 83 species of kukri snakes in the Oligodon genus in Asia. The snakes typically measure no more than 3 feet (100 centimeters) long, and the group's name comes from the kukri, a curved machete from Nepal, as its shape is reminiscent of the snakes' large, highly modified rear teeth. Kukri snakes use these teeth for slicing into eggs, but they can also be formidable slashing weapons (as some very unfortunate frogs have discovered).

In one study, published Feb. 15 in the journal Herpetozoa, scientists described three snake attacks on rotund banded bullfrogs (Kaloula pulchra), which are so round that they are also known as bubble frogs or chubby frogs. They have brown backs with lighter stripes down their sides and cream-colored stomachs, and they measure up to 3 inches (8 cm) long, according to Thai National Parks. 

Two of the attacks were by Taiwanese kukri snakes, and took place in Hong Kong in October 2020. One snake, filmed on Oct. 2 in a residential neighborhood garden, emerged from a hole in the ground to bite a passing bubble frog, slicing open the frog and stuffing its head inside. Snake and frog tussled for about 40 minutes; the snake performed about 15 body rotations, or "death rolls," during the battle, according to the study. 

"We believe that the purpose of these death rolls was to tear out organs to be subsequently swallowed," Henrik Bringsøe, lead author of both studies and an amateur herpetologist and naturalist, said in a statement.

A second Taiwanese kukri snake was discovered on Oct. 8 in an urban park while "energetically" dining on a frog's organs that were "exposed and visible," the study authors wrote.

The third attack on a bubble frog was by a small-banded kukri snake — the species that was first documented exhibiting this behavior — on Sept. 15, at a factory site outside a small village in northeastern Thailand. During the struggle, the snake performed 11 death rolls, its teeth buried firmly in the frog's belly.

"The snake’s efforts resulted in its teeth penetrating the abdomen to such an extent that blood and possibly some organ tissue appeared," the scientists reported. "Eventually, the frog was swallowed whole while still alive."

Another study, published on the same day in Herpetozoa, presented an observation of an ocellated kukri snake feasting on an Asian common toad (Duttaphrynus melanostictus) inside a lodge in a national park in southern Vietnam. These toads are stout, thick-skinned and variably colored, and they measure about 3 inches (8.5 cm) long, according to Animal Diversity Web, a biodiversity database maintained by the University of Michigan's Museum of Zoology. 

Observers recorded this attack on May 31, 2020. The toad was already dead at the time, "and the snake was moving its head and neck side to side as if trying to work its way inside," the study authors wrote. Minutes later, the snake gulped down the toad whole.

In the 2020 study about small-banded kukri snakes eviscerating Asian common toads, the scientists hypothesized that the snakes selectively ate the organs to avoid the toads' deadly toxins. However, the ocellated kukri snake swallowed the toad after its organ appetizer, hinting that the snakes might have some natural resistance to the toads' poison. 

Chubby frogs also have a built-in deterrent that may encourage predators to go straight for their organs. While the frogs aren't toxic, they defensively secrete a sticky mucous that has an unpleasant taste, according to the University of California, Berkeley's AmphibiaWeb.

"We hope that future observations may uncover additional aspects of the fascinating feeding habits of kukri snakes — though we may indeed call them gruesome!" Bringsøe said in the statement.

Originally published on Live Science.

Huntsman spiders in Madagascar eat tiny frogs, and scientists suspect that the spiders catch their prey by weaving "traps" made of leaves, to lure the frogs inside with a promise of protection from the sun.

In 2017, researchers spotted a spider in the Damastes genus clutching a Heterixalus andrakata tree frog — the second time that Madagascar spiders have been seen eating frogs. The spider was enjoying its meal while crouching inside a pocket crafted from two leaves that were still attached to a tree; the leaves' edges were sealed together with spider silk, leaving a small opening.

The scientists later found three more spiders huddled inside such makeshift leaf shelters. Though none of them was snacking on a frog, the earlier find suggests that the spiders build these leaf pockets so they can ambush frogs looking for a shady retreat. 

Related: In photos: Fish-eating spiders around the world

Spiders around the world devour up to 880 million tons of insects each year, but animals with backbones can also end up on an arachnid's dinner menu. Tropical spiders eat lizards, fish, frogs and mammals, causing "a surprising amount of death" among small vertebrates in the Peruvian Amazon, Live Science previously reported. Bat-eating spiders live on every continent except Antarctica, and viral photos have shown the diversity of spider prey, including a tadpole in western India; a pet goldfish in South Africa; and even a pygmy possum in Southern Tasmania.

H. andrakata frogs measure up to an inch (32 millimeters) long, which is slightly bigger than the Damastes spiders that hunt them, said Dominic Martin, a researcher in the department of Biodiversity, Macroecology and Biogeography at the University of Göttingen in Germany. Martin co-authored a study describing the spiders' leaf traps, published online Dec. 11, 2020, in the journal Ecology and Evolution. 

The researchers discovered the frog-eating spider hiding between a pair of silk-woven leaves, its fangs buried deep in a frog's head. The frog wasn't moving and was presumed to be dead. Four more frogs — still living — were found near the tree, according to the study.

Later in 2017 and in 2018, Martin and his colleagues found three more spiders crouching in similar leaf retreats in different types of trees. Leaves were woven together at the sides with silk and had an opening at the base near the stem, perhaps "enabling prey climbing up the stem of the tree to enter," the study authors reported.

Spiders are known to build retreats in which they can hide from their own predators, and where they wait for potential prey to pass by. However, the behavior of the huntsman caught in the act with a frog meal suggests that these spiders may be weaving leaves "as a trap to catch frogs seeking shelter during daytime," Martin told Live Science in an email.

"The frogs may be tempted to hide between the neatly joined leaves in an attempt to avoid dehydration and predation from, for example, birds," he said.

Confirming this type of hunting technique — and whether the trap is targeted at amphibians or insects and other invertebrates — would require cameras monitoring the spiders as they build their traps, wait inside them and finally capture their prey, Martin said. However, spiders can go for days without food, "so recording such 'rare' events is really difficult," he added. 

Originally published on Live Science.

UPDATE: The tadpole titan affectionately known as "Goliath" died in 2019, according to a tweet written on May 26, 2020 by herpetologist Earyn McGee; she introduced Twitter to Goliath in 2018, when this article was originally published. Scientists with the Southwestern Research Station in Arizona preserved the tadpole and are studying it to better understand its unusual size and morphology, according to the tweet.

An enormous tadpole found in the wild is bigger than a can of Coke — and it's still growing.

Biologists discovered the sizable swimmer in a shallow pond in southeastern Arizona; they were removing invasive American bullfrogs (Lithobates catesbeianus) with the Southwestern Research Station (SWRS), a year-round field station run by the Science Department at the American Museum of Natural History in New York City.

As a volunteer probed a mostly drained pond, she stumbled upon an oversize bullfrog tadpole — the wriggly amphibian was so big that the volunteer initially thought it was a fish, herpetologist Earyn McGee, a doctoral candidate at the University of Arizona and a scientist at SWRS, wrote in a blog post on July 23. 

Related: Pictures: Cute and Colorful Frog Images

What’s the story behind this massive weirdo, which biologists have nicknamed "Goliath?"

McGee tweeted photos of Goliath on June 13, generating more than 13,000 likes and drawing dozens of curious commenters. She explained that Goliath was definitely much larger than the average American bullfrog tadpole, suggesting that his unusual size was likely due to "some sort of hormone imbalance." Researchers at SWRS suspect that this imbalance will likely prevent poor Goliath from ever metamorphosing into a frog, and they are currently investigating what may have caused his unusual condition, McGee wrote.

McGee told Live Science in an email that prior studies describe tadpoles that are similarly massive, but Goliath was the biggest tadpole that she had ever seen in person. And for a growing tadpole, bigger isn't necessarily better, McGee added.

"The drawbacks of Goliath's size is that his respiratory and circulatory system may not continue to support his body size as he continues to grow," she said. On the other hand, a really big bullfrog tadpole would be able to grab more food than smaller tadpoles, which could work out in a giant's favor if food supplies in a small pond are low, McGee explained.

American bullfrogs are the biggest of the North American frogs. They grow to lengths of 8 inches (20 centimeters) or longer, and weigh as much as 1 pound (0.5 kilograms), while tadpoles typically grow to be about 6 inches (15 cm) long, according to the U.S. Fish and Wildlife Service (FWS). The frogs are native to central and eastern states, but were introduced in the southwest in the 1900s because of the widespread popularity of frog legs as food, and can now be found in all lower 48 states, according to the FWS.

Researchers at SWRS brought Goliath back to the station and placed him in a tank for closer examination. To provide a sense of the tadpole's substantial size, one of McGee's photos positioned Goliath next to a banana, and another photo compared him to a can of Coke. His exact measurements — along with data about his growth rate, feeding habits and behavior — are being collected by scientists for a peer-reviewed study, McGee wrote in a tweet.

Original article on Live Science.

Frogs' heads may look smooth and rounded on their surfaces, but peek under the skin of some species and you'll find skulls that resemble the heads of mythical dragons, studded with spikes, spines and other bony structures.

Scientists recently highlighted the diversity of frog skulls in a series of incredible images, part of a new study investigating skull evolution and function in armored frogs.

In these frogs, skulls can be shield-shaped or exceptionally wide; they may be pocked by grooves or adorned with pointy bits that may provide extra protection against being eaten, the researchers reported.

Related: In photos: Cute and colorful frogs

Artificial color in the images indicates variations in bone density in different skull parts, said lead study author Daniel Paluh, a doctoral candidate in the Department of Biology at the University of Florida. In the image of the horned frog Hemiphractus scutatus, "blue parts of the skull, such as the braincase, are lower density than the green regions, including the jaws," Paluh told Live Science in an email.

There are approximately 7,000 known frog species. For the study, the scientists collected data from 158 species representing all of the major frog families. They found that not only was there a lot of variety in skull shapes; some of those variations appeared across different lineages, separated by millions of years of evolution.

"For example, large, fortified skulls with intricate patterns of pits and grooves have independently evolved in the African bullfrog, South American horned frog and the Solomon Island leaf frog," Paluh said. "And all of these species are ambush predators that will eat other vertebrates."

Shovel-headed tree frogs, whose flattened skulls resemble gardening tools, use their heads to block entry to the cracks and holes where they live. Their skulls also have spines, ridges and grooves, "in addition to very wide skull roof bones that provide protection from predators," Paluh explained. 

"Because all frogs look so similar, there has been limited interest in studying the evolution of their anatomy," Paluh said. "Our study demonstrates there is still much to learn about the evolution, ecology and anatomy of these amazing animals."

The findings were published online today (March 27) in the journal Proceedings of the National Academy of Sciences.

• So tiny! Miniature frog species are among world's smallest (photos)
• Nature's most bizarre frogs, lizards and salamanders
• 40 freaky frog photos

Originally published on Live Science.

The world's largest frogs may also have the best pollywog daycare on the market. To protect its wee tadpoles, these enormous amphibians build their own "nursery ponds," sometimes moving rocks more than half their weight to do so, and then guarding the pond to ensure the next generation's survival, a new study details.

The finding marks the first time scientists have described the Goliath frog's (Conraua goliath) unique nest-building and parenting tactics. However, local frog hunters in Cameroon have known about it for years, and they were the first to tell the researchers about the frogs' parental dedication.

In fact, the researchers were studying something completely different (they were studying the diet of Goliath tadpoles) when "we heard about the breeding behavior of the Goliaths and decided to investigate if it [were] true or not," said study senior researcher Mark-Oliver Rödel, curator of herpetology at the Natural History Museum in Berlin. [15 of the Largest Animals of Their Kind on Earth]

The 7.3-lb. (3.3 kilograms) Goliath frog is native to Cameroon and Equatorial Guinea. To learn more about its nesting quirks, the scientists spent part of spring 2018 searching a 1,300-foot (400 meters) section of the Mpoula River in western Cameroon. They also interviewed four frog hunters and two villagers who lived near the river to learn more about C. goliath's habits.

In all, the scientists found 22 breeding sites, 14 of which had almost 3,000 eggs apiece. The team even set up a time-lapse video at one nest, which showed a Goliath guarding the nest at night. 

These frogs are creative builders, constructing three different types of nests, the researchers found. One type, the rock-pool nest, was built on larger rocks within the river, meaning that "frogs were using pre-existing structures for breeding," the researchers wrote in the study. 

For the second type, frogs used naturally existing shallow pools near the river as nests. It appeared that the frogs had enlarged these pools, the researchers noticed, in essence turning a cottage into a McMansion. For the third type, the frogs dug small ponds, surrounding them with large stones, some weighing up to 4.4 lbs. (2 kg). 

Impressively, none of these nests had debris in them, suggesting that the frogs also acted as housekeepers, keeping the ponds clean for their tadpoles. "We have never observed them directly, but from indirect evidence, it is apparent that they push out material (e.g. leaves, pebbles) from natural ponds or push away larger and smaller stones to create their 'own' ponds," Rödel told Live Science in an email. 

It's likely that the male frogs, which are more than 1.1 feet (34 centimeters) long, use "their huge and very muscular hind legs" to move the stones, he added. 

While the researchers never directly witnessed a Goliath frog digging a nest, "the most detailed description we got (from one frog hunter) was that the male would construct the nest while the female waits in proximity," the scientists wrote in the study. "Once the nest is finished, the male whistles to attract the female, which then is grasped by the male and eggs are deposited. Afterwards, the female would guard the nest and subsequently open the nest towards the river."

Is daycare worth the cost?

The frogs invest a substantial amount of energy into nest-building, cleaning and guarding. But is it worth it? If their tadpoles survive, it absolutely is, but it appears each nest has benefits and challenges, the researchers found. Nests within a riverbed can flood from heavy rains, allowing predators such as shrimp and fish to get inside and devour the tadpoles, said Rödel, who is also the president of Frogs & Friends, the nongovernmental organization that co-funded the research. [So Tiny! Miniature Frog Species Are Among World's Smallest (Photos)]

Digging a pond alongside the river would sidestep these predators, but if it doesn't rain for a spell, the pond could dry up, killing the tadpoles. "Thus, each of the three nest types has advantages and disadvantages, and the frogs need to choose what is best at a certain time," Rödel said. 

Goliath frogs aren't the only amphibian superparents out there. The gladiator frog (Hypsiboas rosenbergi) in South America builds nests for its young, while the male African bullfrog (Pyxicephalus adspersus) guards tadpoles and digs channels up to 40 feet (12 m) long to allow tadpoles to escape from drying pools, the researchers noted. However, Goliath is the only known African frog to build nesting ponds, the researchers said.

Unfortunately, the Goliath frog is endangered, according to the International Union for Conservation of Nature, largely because of habitat loss and fragmentation, pollution, disease and hunting. (The frogs are considered a luxury food and are often served at weddings, Rödel said.)

It would be a shame to lose these creatures without fully understanding them, he said. "The reason why we wanted (and actually did) study the tadpoles, was that we needed to know more about the biology of the species, just to make sure we know what to do in case a captive breeding program might be the last chance for the Goliaths' survival in the future."

The study was published online Friday (Aug. 9) in the Journal of Natural History.

• 40 Freaky Frog Photos
• Pictures: Cute and Colorful Frog Images
• Photos: America's Only Lake Titicaca Frogs

Originally published on Live Science.

In recent years, dozens of people in the United States who bought prepackaged salads at their local grocery stores found unexpected extra ingredients mixed in with their kale and romaine: frogs, lizards, rodents and even a bat.

In 10 instances, the animals were still alive. (Perhaps, that made the encounters less gruesome … or infinitely worse.)

Researchers recently reviewed reports of these animal discoveries dating back to 2003, describing their findings in a new study. They presented 40 examples of bagged salads purchases in 20 states that included unwelcome wildlife stowaways; 38 of these encounters took place during the past decade. [9 Disgusting Things That the FDA Allows in Your Food]

The scientists collected data on incidents that had been covered by news outlets online, noting details such as the date and location of the animal discoveries; the type of produce; whether the produce was boxed or bagged; and the animal species — and if it was dead or alive. For the dead animals, the scientists recorded "whether the animal was whole or partial," they wrote in the study, published online July 20 in the journal Science of the Total Environment.

Of the animals found in salad, about 53% were frogs and toads, and most of the frogs were in the treefrog group. Around 23% of the salad animals were reptiles, while nearly 18% were mammals and the rest were birds, the scientists reported. Most of the mammals were rodents, but the one instance of a bat in salad — a Brazilian free-tailed bat (Tadarida brasiliensis) found in Florida in 2017 — received significantly more media attention than other animals, likely because bats are known vectors for many diseases that affect people, the researchers explained.

They also noted that animal appearances were three times more common in bags of conventional vegetables than in organic greens.

And though this study focused on animals with backbones, the researchers found "numerous instances" of invertebrate life in packaged salads.

"Pending a thorough review, these may in fact outnumber the vertebrate cases," they wrote. It's also possible that wildlife ends up in packaged salad even more frequently than their findings suggest, as some incidents may have gone unreported or were covered only in print media, which was not included in this study, the scientists added.

Prepackaged salads have surged in popularity since their introduction in the 1980s, and the industry's rapid growth and increasing reliance on automated production pipelines could explain how small, wild animals could bypass safety features and end up sealed inside a salad bag, the study authors reported.

This is the first study to address these recurring instances of small vertebrate wildlife in salad, and "it remains unclear whether these occurrences indicate a food-safety crisis or a complaint against food quality," according to the study. Further observations of the harvesting and production process will be necessary in order to pinpoint when and how the animals find their way into salad bags, and what steps might be taken to keep them out, the authors concluded.

• 15 'Disgusting' Foods Will Have Your Taste Buds Begging for Mercy
• Nature's Most Bizarre Frogs, Lizards and Salamanders
• 40 Freaky Frog Photos

Originally published on Live Science.

In eastern Brazil's Atlantic Forest, poisonous "pumpkin toadlets" use their vivid colors to warn off predators. But these tiny frogs also broadcast a secret visual signal: They glow bright blue under ultraviolet light.

Scientists unexpectedly discovered the glowing patterns in two species of pumpkin toadlets (Brachycephalus ephippium and B. pitanga) while investigating the tiny frogs' mating calls. To the human eye, the frogs appear orange, red or yellow in natural light.

But when researchers shone a UV lamp on the frogs, blue patterns emerged on the toadlets' heads, backs and legs. [In Photos: Cute and Colorful Frogs]

Fluorescence is extremely rare in land animals with backbones, and while scientists don't know how the pumpkin toadlets use their glow, it may help them to recognize prospective mates or protect them from predators, the researchers reported in a new study.

Unlike bioluminescence, in which chemical reactions in an animal's body generate light, fluorescence won't work in complete darkness. In fluorescence, special molecules absorb light and then emit it at longer wavelengths, creating a glow that usually shows up in shades of red or green.

Corals, scorpions and a rare type of sea turtle fluoresce; in 2018, scientists discovered that chameleons fluoresce, too. Another team of researchers found in 2017 that two species of South American tree frog had fluorescent skin, according to the authors of the new study. However, the pumpkin toadlets' glow is more like that of chameleons, originating in the animals' bones.

In fact, bony plates on the toadlets' head and back were "exceptionally fluorescent," though chemical analysis would be required to identify the compounds that lend the frogs their intense shine, the scientists reported.

How does glowing benefit the toadlets? There's no evidence yet to suggest how the frogs use their glow, but it may serve as an extra warning to predators about the frogs' toxic coating, as some birds and spiders can see fluorescence in natural light, lead study author Sandra Goutte told Live Science. Goutte is a postdoctoral associate at New York University Abu Dhabi in the United Arab Emirates.

Another possibility is that the tiny frogs use their glow to communicate with each other. Pumpkin toadlets lack a middle ear, so they can't hear themselves calling; it's possible that a glowing signal helps them with mating success or allows the frogs to recognize their own species.

"But that's only true if the frogs can see it," Goutte said. "And we don't know if they do."

The findings were published online today (March 29) in the journal Scientific Reports.

• So Tiny! Miniature Frog Species Are Among World's Smallest (Photos)
• Nature's Most Bizarre Frogs, Lizards and Salamanders
• 40 Freaky Frog Photos

Originally published on Live Science.

It's possible that during the Triassic period, the crocodile-like phytosaur snapped at a frog-like creature, but missed. It's a good thing it did, because 216 million years later, paleontologists have found the fossils of these tiny creatures, the oldest known frog relative from North America, a new study finds.

This frog — nicknamed the Chinle frog because it was found in the Chinle Formation of northern Arizona — is a big finding, but the creature itself was small, just over 0.5 inches (1.3 centimeters) long.

"The Chinle frog could fit on the end of your finger," study lead researcher Michelle Stocker, an assistant professor of geosciences at Virginia Tech, said in a statement. [40 Freaky Frog Photos]

The frog fossils were found next to the fossils of the crocodile-like phytosaur and those of early dinosaurs, the researchers said. The scientists, however, didn't find entire frog skeletons, but rather a few fragmented ilium, or hip bones, from several of these ancient frogs during an excavation in May 2018. But they hope to find more of the frogs' fossils soon, which is why they haven't given the creature a scientific name yet.

They are still sifting through the dirt and rock excavated at the site, where they expect to find more skull and skeletal material from the frogs — findings they say will be more informative about the identity of this kind of creature, Stocker said.

The team noted that while Chinle specimens are distant relatives of frogs, they are not the direct ancestor of modern frogs. But they're still salientians — a group that includes living frogs and their closely related, extinct relatives.

In fact, the Chinle frog is the oldest known salientian from near the equator, the researchers noted.

That's because during the Triassic period, when these frog-like animals lived, Arizona wasn't where it is today. Instead, the Grand Canyon state was once part of the supercontinent Pangaea and was located about 10 degrees north of the equator, the researchers said.

An analysis of the frogs' hip bones shows that the species shares more features with modern frogs and Prosalirus, an early Jurassic frog discovered in the present-day Navajo Nation, than it does with Triadobatrachus, an early Triassic frog found in modern-day Madagascar.

"These are the oldest frogs from near the equator," Stocker said. "The oldest frogs overall are roughly 250 million years old from Madagascar and Poland, but those specimens are from higher latitudes [than the Chinle frog] and not equatorial."

The discovery of the Chinle frog may also be a sign of things to come. "Now [that] we know that tiny frogs were present approximately 215 million years ago from North America, we may be able to find other members of the modern vertebrate communities in the Triassic period," study co-researcher Sterling Nesbitt, an assistant professor of geosciences at Virginia Tech, said in the statement.

The study was published online today (Feb. 27) in the journal Biology Letters.

• Pictures: Cute and Colorful Frog Images | Amphibians
• So Tiny! Miniature Frog Species Are Among World's Smallest (Photos)
• Photos: America's Only Lake Titicaca Frogs

Originally published on Live Science.

Two decades ago, scientists discovered a sort of archaic fungus infecting frogs in Central America. Called Batrachochytrium dendrobatidis, or chytrid, the fungus appeared to be a rare and devastating threat: It altered the skin chemistry of infected hosts, robbing them of their ability to drink water and absorb electrolytes through their skin, eventually stopping their hearts. It was indiscriminate, able to jump easily between frog species and kill nearly all its hosts.

In a 2007 white paper, the International Union for Conservation of Nature (IUCN) wrote that as a result of the fungus (and the human activity that allowed it to spread all over the world), "the global amphibian extinction crisis and its present dynamics are the worst we have ever faced," adding, "It is the worst infectious disease ever recorded among vertebrates in terms of the number of species impacted and its propensity to drive them to extinction."

Now, a new paper offers some good news: There's evidence from one tropical site that frog ecosystems can adapt to the fungus, with certain infected species dying off and those that remain surviving their infections — likely because they've evolved to become resistant to its effects, and because the fungus itself has become less deadly. [7 Iconic Animals Humans Are Driving to Extinction]

In a paper published yesterday (Oct. 3) in the journal Ecological Applications, researchers describe how they studied tropical frogs in a region about 0.8 square miles (2 square kilometers) in Panama called El Copé. Between 2010 and 2014, researchers slowly wandered the area, picking up frogs and swabbing them for signs of the fungus. They divided the regions into squares of 66 feet by 66 feet (20 by 20 meters), keeping careful records of frogs of each species in each square and whether they turned up infected or not-infected.

While about half the frog species in the area went extinct when the epidemic first reached El Copé in 2004, by the 2010-to-2014 period the remaining populations appeared to have stabilized, researchers found. Infected frogs appeared to survive longer, fewer frogs overall were infected, and researchers didn't find the sorts of drastic population declines that occurred during the initial outbreak.

"Our results are really promising because they lead us to conclude that the El Copé frog community is stabilizing and not drifting to extinction," Graziella DiRenzo, a biologist at the University of California, Santa Barbara, and the lead author of the paper, said in a statement. "That's a big concern with chytrid worldwide. Before this study, we didn't know a lot about the communities that remain after an outbreak. In some areas, it's still a black box."

The overall outlook for frogs isn't good, the researchers were careful to note, describing the daily reality for the region's frogs as "grim" in the paper. But they showed that things could be a lot worse.

"Our study found that, even though there are a lot of infected individuals, about 98 percent of them are infected at very low levels," Karen Lips, a biologist at the University of Maryland and a co-author on the paper, said in the statement. "We know that, early on, several species played a key role in spreading infection, like Typhoid Mary. But some of these species are now gone, so the entire ecosystem is totally different. It's almost not comparable to what was there before."

It's unclear what the long-term prospects for frogs are at this point, whether in Panama or elsewhere. However, Lips said, "If enough frog species in a given place can survive and persist, then hopefully someday a vibrant new frog community will replace what was lost."

Originally published on Live Science.

Live Science sat down with Cooke yesterday (April 17) to explore the wild interactions and historical misunderstandings humans have had with animals dating to the time of Aristotle. And believe us when we say there are misunderstandings. So. Many. Misunderstandings. 

For instance, people had no idea for centuries where the stork and other birds went in the winter. Nowadays, we know that these birds migrate to warmer places. But before this was widely known or accepted, the 17th-century scientist and minister Charles Morton proposed another idea: Storks flew to the moon "in one great flock," he wrote, according to Cooke's book. [In Photos: The Amazing Penguins of Antarctica]

This incredible journey took the stork about 60 days, each way, giving the birds enough time to spend four months on Earth and four months on the moon, Morton incorrectly calculated. Granted, "here, he failed to account for the fact that the velocity required for his space-traveling storks to leave Earth's gravitational pull would be some 200 times his calculated top speed, a feat unachievable without the help of NASA's finest rocket boosters bound to the birds' backs," Cooke wrote.

In all, Cooke explores the odd histories of 13 animals: eel, beaver, sloth, hyena, vulture, bat, frog, stork, hippo, moose, panda, penguin and chimpanzee.

These tales include the true-life story of how a psychologist at the University of Oklahoma adopted a chimpanzee to an attempt to raise her like a human, and how Sigmund Freud tried, in vain, to discover the testicles of the eel. Then, she contrasts these stories with new research that's going on today, including researchers who study chimp communication in the primates' native habitat, rather than in a laboratory.

"I'd hope that the book helps us understand animals on their own terms," Cooke told Live Science, "and to appreciate them for what they are and not what we want them to be."

Original article on Live Science.

Watch the skies

Umbrellas and galoshes will shield you from rain, snow and hail — but what about showers of spiders, satellites, and raw mystery meat?

Humans, it turns out, have caught them all falling from the sky at one point or another. And while some freak rain occurrences are easily explained by atmospheric forces, others have endured for hundreds of years as unsolved meteorological mysteries. Join us now as we tick through some of the weirdest weather phenomena to ever face the planet, and see how many science can solve.

Frozen iguanas

While residents of Tallahassee, Florida braced for their first measurable snowfall in 28 years this January, other Floridians braced for a hailstorm of frozen iguanas. The cold-blooded lizards are an invasive species in Florida, where they like to make their homes in suburban tree branches. "When the temperature goes down, [iguanas] literally shut down, and they can no longer hold on to the trees," said Ron Magill, wildlife expert and communications director for Zoo Miami. The paralyzed iguanas tumble out of the trees and remain stock-still (but not dead) until temperatures warm, allowing them to revive and scurry off again. (Florida also saw an iguana rain in 2008.)

Fish

In Mexico, fish fall from the sky so often there’s a name for it: "lluvia de peces" (literally, rain of fish). In fact, coastal cities around the world from California to England to India have all seen their own versions of the fishy phenomenon — so what’s going on? Poseidon’s wrath aside, one possible explanation (though there are several theories) is that these fish-falls stem from weather events called waterspouts — basically, a tornado that touches down on water. Sometimes, when the whirling winds suck up water from lakes or oceans, they lift up schools of unsuspecting fish (and other water-life) with them. The winds carry the critters inland, then ultimately drop them on land with whatever water remains.

Frogs

Waterspouts may also be to blame for the straight-up-Biblical phenomenon of frog rain. Tiny toads have been recorded dropping from the sky at least since 1873, when an article in Scientific American reported, "a shower of frogs which darkened the air and covered the ground for a long distance" following a rainstorm in Kansas City, Missouri. The precise cause of the 1873 frog rain is unknown, but scientists generally apply this logic to frog falls: if a strong wind could overturn a car or rip a tree from the ground, it could certainly carry a frog far from its swampy home.

Meat

OK, but what makes chunks of meat drop from the sky? This question captivated America in 1876 when, over the course of several minutes, a field in Bath County, Kentucky was beset by a steady rain of what appeared to be flakes of beef . According to a report in Scientific American, two gentleman who tasted the puzzling sky beef could not agree on whether it was actually mutton or venison; a third man attested it was, in fact, bear. One analyst concluded it was not meat at all, but a type of cyanobacteria that congealed into a fleshy jelly when exposed to rain. Others were convinced it was buzzard barf. For better or worse, the mysterious Kentucky Meat Shower of 1876 remains that — a mystery.

Blood rain

Sometimes, microorganisms are easier to blame for weird weather phenomena. Case in point: Residents of several villages in northwest Spain received an unpleasant surprise in 2014, when they noticed that the water in their fountains had turned a gory shade of red. The tint wasn't left behind by a guilty murderer's bloody hands, but rather by microscopic algae that arrived in a recent rainfall. Studies confirmed that the "blood rain" was teeming with freshwater algae called Haematococcus pluvialis, which produce a red pigment when they're stressed.

Spiders

Millions of tiny spiders fell from the sky in Australia in 2015 — and it wasn’t the first time. This phenomenon, known as "spider rain" or "angel hair” (because of the silky, hairlike threads the spiders leave behind), occurs when huge groups of spiders engage in a behavior called "ballooning" at the same time. When ballooning, spiders "climb some high area and stick their butts up in the air and release silk — then they just take off," Rick Vetter, a retired arachnologist at the University of California, Riverside told Live Science at the time. "This is going on all around us all the time. We just don't notice it."

Golf balls

According to a local news report, "dozens and dozens and dozens" of golf balls littered the streets of Punta Gorda, Florida following a heavy downpour in 1969. The balls baffled the waterfront community; no golf courses or driving ranges in the area reported any balls missing. The likeliest explanation? Perhaps a waterspout passed over the pond at a nearby golf course, sucking decades of poorly-aimed balls into the Florida sky.

Russian gold

It rained gold in Siberia for a few glorious minutes in March 2018, when an old transport plane carrying an estimated $378 million in gold, platinum and diamonds accidentally spilled its cargo while taking off from Yakutsk Airport. According to airport officials, the plane's cargo hatch ripped open during takeoff, causing nearly 200 solid-gold bricks to tumble onto the runway and nearby snow. Sadly for treasure hunters, police say they have recovered all of the spilled booty.

Boiled bats

In January 2018, hundreds of heat-stricken bats fell from the trees of Campbelltown, Australia after a heat wave launched local temperatures up to 111.5 degrees Fahrenheit (44.2 degrees Celsius). The bats — a species of flying fox called Pteropus poliocephalus — can safely handle temperatures of about 86 degrees F (30 degrees C) before the heat addles their brains. After that, "they basically boil," Kate Ryan, the colony manager for the Campbelltown bats, told a local paper. More than 200 bats were ultimately found dead, many of them babies.

Various space stations

It’s exhausting work orbiting the Earth at 17,500 miles (28,000 kilometers) per hour. Satellites are generally pretty good about taking this speed in stride but, sometimes, they lose steam and fall. At press time, for example, China’s Tiangong-1 satellite — a 9.4-ton (8.5 metric tons) prototype space station — is tumbling inexorably toward Earth, expected to break apart in the planet’s atmosphere in the next few weeks. It will not be the first: over the past 50 years, more than 5,900 tons (5,400 metric tons) of space debris has survived re-entry into Earth's atmosphere. Luckily, your odds of being hit by such debris are about a million times smaller than your odds of winning the Powerball jackpot — so play on!

In a stunning frog photo shared widely from Reddit, a swallowed snake isn't going down without a fight.

The swallowed snake likely didn't stay alive for long — though a frog's prey is usually gulped down alive and kicking, once the frog's mouth snaps shut, the end comes quickly, Jonathan Kolby, director of the Honduras Amphibian Rescue and Conservation Center, told Live Science in an email. Even if the prey doesn't go down easily, the frog is usually none the worse for wear, he said.

"It's easy to imagine that swallowing a vigorously struggling animal would hurt the frog," Kolby explained. "But after being swallowed, most prey items likely suffocate and die within a minute or two while being squeezed and held in place by muscles in the frog's digestive tract."

And it's not at all uncommon for a snake to be on a frog's menu, Kolby added.

"Tree frogs often consume a wide variety of prey, including snakes and even rodents, all according to how large a frogs' mouth is," he said.

The frog was identified as an Australian green tree frog (Litoria caerulea) in a tweet posted on Oct. 16 by Jodi Rowley, a curator of Amphibian and Reptile Conservation Biology with the Australian Museum and the University of New South Wales. In another tweet, Rowley suggested that the frog's esophagus appeared smaller than might be expected for an animal with such a wide gape, but it was probably somewhat constricted because the snake was still in the process of being swallowed.

The snake appears to be a baby brownsnake, according to Paul Oliver, a postdoctoral researcher at the Australian National University. That makes this interaction somewhat unusual, as many snakes are diurnal — active during the day — and frogs are nocturnal, Oliver explained.

"It seems unlikely to have occurred naturally (but then give things enough time in nature — all sorts of unlikely things do happen)," Oliver told Live Science in an email.

One possibility? "Human agency may have played role in the snake meeting the frog, but subsequently the frog's instincts to eat anything small took over," said Oliver, who studies the systematics and evolution of frogs and lizards.  

In fact, tree frogs are referred to by some as "labradors of the frog world" for their indiscriminate eating habits, as they are known for trying to eat "just about anything they can fit into their mouths," Kathleen Doody, a researcher with the School of Biological Sciences at the University of Queensland in Australia, told Live Science in an email.

Regardless, from the frog's perspective, having your meal trying to writhe its way back up your throat is probably not a pleasant experience. But there are even more extreme examples of a meal turning disastrous for frogs, Kolby told Live Science.

Epomis beetle larvae, which look like tempting grubs to a hungry frog, are actually deadly carnivores that prey on their would-be predators, Kolby said. The larvae lure the frogs closer by waving their antenna, then strike with their powerful mandibles, latching onto the frog and consuming it alive, he said.

Did the snake in the photo somehow manage to wrest itself from the frog's maw and wriggle its way to freedom? We may never know how this particular incident ended. But for one moment in a life and death struggle frozen by a photographer's lens, the prey came out ahead.

Original article on Live Science. 

A group of modern frogs whose comically rotund bodies and giant mouths earned them the nickname "Pac-Man" frogs is attracting attention — not for the size of their maws, but for the power of their bite. And their extinct relative, known as a "devil frog," may have packed even more of a mouthy wallop, researchers reported in a new study.

Recently, researchers conducted the first measurements of bite strength in frogs. Initially, the scientists calculated the bite force in small "Pac-Man" frogs, also known as South American horned frogs. Then, the researchers scaled up their findings to determine bite force in an extinct relative, a giant, armored amphibian known as Beelzebufo ampinga, or "devil frog," that lived about 65 million to 70 million years ago.

The scientists' findings showed that the extinct devil frog would have had a vise-like mouth grip even more powerful than that found in living horned frogs. Combined with its enormous size, Beelzebufo's bite strength could have allowed the animal to prey even on juvenile dinosaurs, the scientists reported in a new study. [Eye-Swallowing and Mouth Birth: Freaky Facts About Frogs]

Most frogs have relatively weak jaws and feed on small prey that they subdue primarily with their sticky tongues, the study authors wrote. But roly-poly South American horned frogs in the genus Ceratophrys have an exceptionally powerful bite that allows them to snatch and hold prey almost as big as the frogs themselves. The researchers questioned how strong that bite would have been in similarly big-headed frogs that lived millions of years ago.

The scientists began by looking at Cranwell's horned frogs, testing the bite force of eight frogs measuring between 1.6 and 3.8 inches (4.0 and 9.6 centimeters) in length, with heads that were 0.6 to 1.3 inches (1.5 to 3.2 cm) long and 0.9 to 1.8 inches (2.2 to 4.6 cm) wide. Researchers had the frogs clamp their mouths on a force transducer — a device for measuring bite force — made of two metal plates padded with leather strips to protect the frogs' jaws.

Once the researchers knew the frogs' bite force, they could scale that measurement up by adjusting parameters such as the frog's head and body size and estimating the accompanying changes in muscle size, the study said. Next to the small "Pac-Man" frogs, the extinct devil frog was gargantuan, with a body measuring about 16 inches (41 cm) long and a head reaching about 6 inches (15 cm) in width.

The study's calculations predicted that at that size, the devil frog's bite would have been as powerful as that of a wolf or of an adult female lion or tiger. That certainly would make Beelzebufo capable of taking down small crocodiles or dinosaurs that shared its habitat — especially if its hunting habits were similar to the aggressive and tenacious chomp of the "Pac-Man" frogs, the researchers explained.

"Horned frogs have quite an impressive bite, and they tend not to let go," the study's lead author, A. Kristopher Lappin, a professor of biological sciences at California State Polytechnic University in Pomona, said in a statement.

Lappin noted that he spoke "from experience," though he did not provide details as to what exactly that experience was.

By comparison, the bite of the much larger — and possibly dinosaur-consuming — devil frog would have been "remarkable," Lappin said in the statement. "Definitely not something I would want to experience firsthand."

The findings were published online yesterday (Sept. 20) in the journal Nature: Scientific Reports.

Original article on Live Science.

The mass extinction that wiped out the dinosaurs paved the way for a totally different type of creature to take over — frogs.

The slimy amphibians exploded in numbers and diversified in the millions of years after a massive asteroid wiped out the dinosaurs, taking advantage of the huge holes in the ecosystem that extinct creatures left behind, a new study suggests.

"Frogs have been around for well over 200 million years, but this study shows it wasn't until the extinction of the dinosaurs that we had this burst of frog diversity that resulted in the vast majority of frogs we see today," study co-author David Blackburn, associate curator of amphibians and reptiles at the Florida Museum of Natural History on the University of Florida campus, said in a statement. "This finding was totally unexpected." [Wipe Out: History's Most Mysterious Mass Extinctions]

Massive extinction

The dinosaurs reigned for about 175 million years, during a period known as the Mesozoic era. Then, about 65 million years ago, a massive asteroid wiped them out.

Frogs, meanwhile, have been around for about the past 200 million years, but how and exactly when species of frogs emerged and diversified has been murky. Some studies suggested that the major frog families — Hyloidea, Microhylidae and Natatanura — diverged sometime in the Mesozoic era.

Planet of the frogs?

To answer that question, Blackburn and his colleagues analyzed 95 genes from each of 156 different frog species alive today. They then combined this data with previously reported data from another 145 species. From this data, they created an evolutionary tree mapping out the history of all frog families.

Then, the team pored over frog fossils to anchor genetic changes in frogs to specific points in time. The team found that the three major families of frogs all diverged around the same time, the researchers reported today (July 3) in the journal Proceedings of the National Academy of Sciences. It turned out, this explosion in frog species, and the divergence of the major frog families, occurred right at the KT boundary (the boundary between the Cretaceous and the Paleogene periods), soon after the dinosaurs went extinct. Though the findings contradict previous research, they also make sense because there were so many holes in the ecological niches vacated by dinosaurs and other affected species, study co-author David Wake, an evolutionary biologist at the University of California, Berkeley, said in a statement.

"We think the world was quite impoverished as a result of the KT event, and when the vegetation came back, angiosperms dominated. That's when trees evolved to their full flowering," Wake said. "Frogs started becoming arboreal. It was the arboreality that led to the great radiation in South America in particular."

Originally published on Live Science.

When they grow up, they'll be big, gray-green and saggy-skinned, but for now, the newest critically endangered babies at the Denver Zoo are slender and sleek.

The hatchlings are the first tadpoles of Lake Titicaca frogs (Telmatobius culeus) ever born in North America. They're the offspring of two frogs from the Huachipa Zoo in the amphibians' native Peru. The Denver Zoo is the only Northern Hemisphere institution caring for this frog species, which is native to a single high-altitude lake in the Andes. The tadpoles hatched on Valentine's Day (Feb. 14).

Lake Titicaca frogs are critically endangered because of environmental contamination and poaching. They're the key ingredient in a traditional health shake called Jugo de Rana, or frog juice, which is rumored to increase vitality and virility (there's no evidence that it does). In an effort to conserve the species, the Denver Zoo partnered with Cayetano Heredia University and the Huachipa Zoo in Lima to bring 20 adult Lake Titicaca frogs to Colorado in November 2015. [See Photos of the Only Lake Titicaca Frogs in the US]

"In the time we've had the Lake Titicaca frogs, we have gained so much insight to this unique species," Tom Weaver, assistant curator of reptiles and fish at the Denver Zoo, said in a statement. "We feel very proud that we are able to provide that opportunity."

Strange frogs

Lake Titicaca sits at an elevation of 12,500 feet (3,811 meters), and its waters are chilly — Lake Titicaca frogs are adapted to survive in water with temperatures of 50 to 60 degrees Fahrenheit (10 to 17 degrees Celsius). The frogs can grow to 20 inches (50 centimers) long and weigh up to 2 pounds (0.9 kilograms). Their baggy skin provides them extra surface area so that they can more efficiently pull oxygen from the water, according to the zoo.

Their skin has given them the rather unappealing nickname "scrotum frog," which is not the only reason one might not want to grind them up into a smoothie. Wild frogs can also carry cholera, according to Denver Zoo officials. The grandparents of the current Denver Zoo tadpoles were confiscated from the illegal wildlife market in Peru and Bolivia and kept at the Huachipa Zoo. The parents hatched as tadpoles at that zoo before making the trip to Denver in a cooler.

Most of the tadpoles are now on display in Denver. When they mature into frogs, some will stay at the Denver Zoo, while others will be sent to other accredited institutions. Before the Denver Zoo received its Lake Titicaca frogs, it had been more than 20 years since any zoo in America had housed the species.

"Our work is raising much-needed awareness for the plight of this frog for our guests, children and adults, and will soon do the same for those who visit the other institutions which will soon be a home for the species," Matt Herbert, the zoo's director of conservation education, said in the statement.

Original article on Live Science. 

Newborn poison frogs of Peru have quite an appetite. If left home alone in their hatching pool, the ravenous tadpoles will eat each other. To keep the tadpoles from gorging on their siblings, their doting father will carry them one at a time on his back and drop them in separate pools, where other food is available.

Some frog fathers, however, abandon their young. For unknown reasons, these males leave and never return to fetch their developing offspring.

Researchers have now found that abandoned tadpoles don't wait for their father to return, because they run the risk of getting eaten by cannibalistic siblings. Instead, they try to piggyback on any adult frog that happens to visit the pool to breed, sleep or cool off in it. What's more, the researchers found that it made no difference to the tadpoles if the visiting adult belonged to the same or a different species. [40 Freaky Frog Photos]

Lisa Schulte and Michael Mayer, of the Department of Biogeography at Trier University in Germany, studied the behavioral response of tadpoles of the Neotropical poison frog Ranitomeya variabilis toward adults of the same species as well as two different species (Ranitomeya imitator and Hyloxalus nexipus).

To perform the experiments, the researchers set up a makeshift laboratory in an unused coffee plantation next to a forest in Peru. They left tadpoles hatched from the same egg clutch in a plastic bowl filled with water and then placed an adult frog in the bowl. The researchers noticed that the tadpoles approached adults of all three species and tried to wriggle their way up the frogs' backs.

"The tadpoles beg for transportation; it surprised us that for them it does not matter if it is their own species or not," Mayer told Live Science in an email from Peru.

Out of 39 tadpoles, two were able to hop on the adult's back — one on the R. variabilis male (same species) and the other on the R. imitator male (same genus but different species). The tadpoles received no help from the adult frogs, which expressed no interest in piggybacking the tadpoles, "affirming that the tadpoles followed the frogs, not vice versa," Schulte and Mayer wrote in their study, published online May 5 in the Journal of Zoology.

"When in acute danger, they do not passively wait for their parents to pick them up," the researchers wrote, "but instead show a strong, nearly aggressive form of approaching and mounting adults."

Original article on Live Science.

Every year in March or April, Jewish people around the world celebrate Passover — a holiday that marks the Exodus, when the Jews escaped slavery in Egypt and moved to Israel, as recounted in the Torah (the Hebrew Bible, which collects the first five books of the Christian Old Testament).

Before Moses could lead the 40-year journey through the desert, he needed the pharaoh's permission to free the Jews from enslavement, according to the Torah. Egypt’s ruler had a hard heart, however, prompting the Lord to send down 10 plagues until the pharaoh changed his mind.

Could any of Egypt’s plagues have occurred through natural phenomena, rather than an actual act of God? Live Science looks at possible scientific explanations behind each of the 10 plagues.

Blood

To unleash the first plague upon the Egyptians, Moses struck the river Nile with his staff, turning its waters to blood. At the same time, his brother Aaron similarly transformed canals, tributaries, ponds and pools throughout Egypt.

After the water turned to blood, "the fish in the Nile died, and the Nile stank, so that the Egyptians could not drink water," according to the Hebrew Bible (Exodus, chapter 7, verse 21).

How can science explain this transformation? The sudden appearance of red-hued waters in the Nile could have been caused by a rapid bloom of red algae. This occurs when certain conditions — such as more light or nutrients — enable microscopic algae to reproduce to such an extent that the waters they live in appear to be stained a bloody red.

This phenomenon is known as a "red tide" when it happens in oceans, however red algae are also commonly found in freshwater ecosystems. These so-called algal blooms can be harmful to wildlife as the algae produce toxins that can kill fish and make shellfish dangerous to eat. Fumes from densely-concentrated algal blooms can also disperse toxins in the air, causing breathing problems in exposed individuals.

Frogs

For the second plague, Moses conjured vast quantities of frogs that swarmed into people's homes — some even found their way into the Egyptians' beds, ovens and cookware.

As it happens, the phenomenon of "raining frogs" has been reported multiple times around the world throughout history. For instance, an 1873 report in the magazine Scientific American described a "shower of frogs" caused by a rainstorm in Kansas City, Missouri. These kinds of events may have been the result of strong winds carrying frogs from one place to the next.

More recently, in May 2010, thousands of frogs emerged from a lake in northern Greece likely in search of food — which disrupted traffic for days, CBS News reported.

Lice

The third plague, lice, could mean either lice, fleas or gnats based on the Hebrew word, "Keenim."

If a toxic algal bloom caused the first plague and a pile of dead frogs followed, it's not surprising that a swarm of insects of some sort came after. That's because frogs typically eat insects so without them, the fly population could have exploded, said Stephan Pflugmacher, during a National Geographic television special about the plagues in 2010. At the time, Plufmacher was a climatologist at the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin.

What makes this particular event worse is that both body lice and fleas can theoretically transmit the bacterium Yersinia pestis, which causes bubonic plague. A louse infestation could have set the stage for the later plagues, such as boils.

Scientists have also argued that the sickness that later killed livestock may have been the viral infectious diseases Bluetongue or African horse sickness — both of which can be spread by these plague insects.

Related: Ancient Judeans ate non-kosher fish, archaeologists find

Wild beasts

The Hebrew word for the fourth plague, "arov," is ambiguous. The word roughly translates to "a mixture" in English and, over the years, rabbis have interpreted this to mean wild animals, hornets or mosquitoes, or even a wolf-like beast that attacks at night.

The plague of wild beasts may also have been referring to an array of different types of animals, including snakes, scorpions, and even lions and bears.

Conversely, in a 1996 paper that tried to provide epidemiological explanations for the plagues, scientists John Marr and Curtis Malloy argued that the beasts in the fourth plague were most likely stable flies (Stomoxys calcitrans).

Bites from these flies may have led to the boils that occurred later on in the story, Marr and Malloy suggested.

Diseased livestock

The fifth plague called down on Egypt was a mysterious and highly contagious disease that swiftly killed off the local livestock. This biblical scourge is reminiscent of a real plague known as rinderpest — a now-eradicated, infectious and deadly viral disease that decimated populations of cattle and other ruminants across Europe and Africa during the 18th and 19th centuries.

Rinderpest was caused by a virus in the same family as the canine distemper virus and the human measles virus. The disease caused a range of symptoms in infected animals, such as a high fever, diarrhea, dehydration and mouth ulcers.

The disease is thought to have originated in Asia approximately 10,000 years ago, when the extinct ancestors of modern cattle were first domesticated. It is believed to have reached Egypt along prehistoric trading routes around 5,000 years ago.

The fatality rate of rinderpest was exceptionally high — sometimes reaching 100% — and resulted in the deaths of millions of cattle globally before it was eradicated in 2010.

Boils

Shortly after the Egyptians' livestock died off, they were distracted by the sixth plague — an extremely uncomfortable plague of boils that covered their bodies. Boils are painful, pus-filled bumps that form under the skin. They are typically caused by a species of bacteria known as Staphylococcus aureus that is commonly found on skin and inside the nose.

An outbreak of the highly infectious and now eradicated disease smallpox —which caused distinctive raised blisters — could result in masses of people simultaneously coming down with rashes and welts. Smallpox is thought to have affected communities in Egypt at least 3,000 years ago, based on evidence of scars found on mummies dating back to that period.

Related: Trove of Jewish artifacts discovered beneath a synagogue destroyed by Nazis during WWII

Fiery hail

The seventh plague brought a heavy hail accompanied by thunder and streaming fire. This chaotic weather struck down people, livestock and trees, although the area of Goshen — where the Israelites lived — was spared, according to the Torah (Exodus, 9:27).

A nearby volcanic eruption around 3,500 years ago on the Greek island of Santorini may explain this plague, as well as others. It's possible that the volcanic ash mixed with thunderstorms above Egypt, leading to dramatic hailstorms, an astrophysicist told the Telegraph.

Locusts

When the pharaoh once more refused to let the Jewish people go, hungry locusts descend as the eighth plague. As Moses warned the pharaoh: "They shall cover the face of the land, so that no one can see the land" (Exodus 10:5). Such a pestilence would devour all the remaining plants that the hail did not destroy, Moses also said.

The volcanic eruption on Santorini may have created favorable conditions for the locusts, Siro Trevisanato, a Canadian molecular biologist and author of "The Plagues of Egypt: Archaeology, History and Science Look at the Bible" (Gorgias Press, 2005), told The Telegraph.

"The ash fallout caused weather anomalies, which translates into higher precipitations, higher humidity," Trevisanato said. "And that's exactly what fosters the presence of the locusts."

Darkness

The darkness that descended on Egypt for three days as the ninth plague may have been a solar eclipse or a cloud of volcanic ash, scholars suggest.

For instance, one theory is that the darkness may have coincided with an eclipse on March 5, 1223 B.C. However, the fact that the Israelites still had light in their homes during the plague of darkness weakens this hypothesis.

An alternative theory is that the volcanic eruption on Santorini approximately 3,500 years ago spewed ash that caused the darkness, reported The Telegraph. Indeed, scientists have discovered bits of glass from the volcano in the sole of the Nile delta, according to The New York Times. However, the eruption happened about 500 miles (800 kilometers) from Egypt and before the Exodus event took place, reducing the validity of this theory, argued The Christian Courier.

Killing of the firstborn

In the 10th and final plague, Moses tells the pharaoh that all firstborns in the land of Egypt would die.

Some scholars argue that a possible explanation for this plague is that firstborns died after eating grain that was contaminated with mycotoxins in moldy granaries. Mycotoxins are poisonous substances that can cause illness and death in humans and other animals. First born children and animals may have been given preferential access to the grain, therefore making them more susceptible to the harmful effects of such mycotoxins.

A yellow-green frog with eye-catching stripes that was discovered recently in Ecuador's cloud forests has now been deemed a new species of rain frog, according to a new study.

Across the U.S. and Canada, there are about 110 described frog species. By comparison, Ecuador — which is about the size of Colorado — is home to 570 frog species, and counting, according to the researchers. The latest species discovery in Ecuador came from an expedition that focused on studying a similar, threatened frog called the ornate rain frog (Pristimantis ornatissimus).

Scientists previously thought the ornate rain frog population was a single species. [Cute and Colorful Frog Images]

"[We] were characterizing the genetic differences among populations of the ornate rainfrog, which was thought to be a single species of frog until we uncovered one population that was strikingly different from all others and turned out to be a distinct species," co-author Chris Funk, a biologist at Colorado State University, said in a statement.

The new rain frog species, named the Ecuadorian rain frog (Pristimantis ecuadorensis), is already considered "endangered" based on guidelines from the International Union for Conservation of Nature. An "endangered" classification means the recently discovered rain frog is at a very high risk of extinction in the wild. The researchers said the frog is at risk due to habitat loss within its already-small range.

Small ranges are common in Ecuador, the researchers said, because the country has a large diversity of habitats and climates defined by the Andes mountain range. The new rain frog species, which was determined via DNA sequencing, makes its home in the Las Pampas region of the western Ecuadorian Andes, the scientists said in the study.

"We know that there's lots of undescribed biodiversity in Ecuador, so you could think this discovery is not a big deal," said study lead author Juan Guayasamin, a professor at Universidad San Francisco de Quito. "But this species, first of all, is spectacular-looking; secondly, it's restricted to a very small area, which once again emphasizes range-restricted, highly threatened biodiversity in the tropics. And lastly, its name ­— the Ecuadorean rain frog — will hopefully draw local and international attention to the endangered species and ecosystems of Ecuador."

The researchers chose the rain frog's name specifically to honor the country's beauty, culture and diversity, they said.

The new species is described in a paper published online March 22 in the journal PLOS ONE.

Original article on Live Science.

Some of the smallest known frogs were recently discovered following a five-year survey in India. Seven new species of "night frogs," in the Nyctibatrachus genus, include four species that are among the tiniest frogs ever found, capable of comfortably crouching on a thumbnail with room to spare.

Though the frogs were abundant in the survey area, their minuscule size and chirping calls — which resemble the sounds of insects — enabled them to remain undetected until now, scientists wrote in a new study.

Their discovery raises the total number of known night frog species to 35, with seven species recognized as miniaturized — smaller than 0.7 inches (18 millimeters). [So Tiny! Miniature Frog Species Are Among World's Smallest (Photos)]

The smallest of the newly described frogs — Nyctibatrachus manalari, N. pulivijayani, N. robinmoorei and N. sabarimalai — measure between 0.5 and 0.6 inches (12.2 and 15.4 mm).

N. webilla and N. athirappillyensis are slightly larger than their cousins at approximately 0.7 inches and 0.8 inches (20 mm) respectively, while the largest of the new finds, N. radcliffei, measured 1.5 inches (38.3 mm).

Night frogs are native to the Western Ghats mountain range, one of the world's richest biodiversity hotspots and a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site. The region runs parallel to India's western coast, covering an area measuring approximately 54,054 square miles (140,000 square kilometers).

It is home to hundreds of species of animals and plants that are recognized as globally threatened, with 145 species listed as endangered and 51 as critically endangered, UNESCO reported in a site description.

Over the past decade, scientists have described 103 new species from the Western Ghats, including the unusual Indian purple frog, which is found nowhere else on Earth and is the only living frog in an evolutionary lineage dating back to the Jurassic.

What the future holds for night frogs — and for many of their fellow amphibians — is uncertain, as more than 32 percent of the Western Ghats frogs are threatened with extinction, according to the study co-author, SD Biju, a biologist and head of the Systematics Lab with the Department of Environmental Studies at the University of Delhi, India.  

"Out of the seven new species, five are facing considerable anthropogenic threats and require immediate conservation prioritization," Biju said.

The new findings emphasize that biodiversity in the Western Ghats is dramatically underestimated — even in well-studied groups like night frogs — and highlight the urgency of implementing conservation measures to protect threatened wildlife, and to preserve the habitats of as-yet undiscovered species, the study authors wrote.

The findings were published online today (Feb. 21) in the open access journal PeerJ.

Original article on Live Science.

Tiny frog

Seven new frog species from India's Western Ghats, a UNESCO World Heritage Site, were recently described in a new study. This pint-sized individual measures 0.54 inches (13.6 millimeters).

Perched on a fingertip

The tiny frog Vijayan's Night Frog (Nyctibatrachus pulivijayani) lives in the Agasthyamala Hills in the Western Ghats, a mountain range that runs parallel to India's western coast.

A rupee for your thoughts

Another tiny frog, Robinmoore's Night Frog (Nyctibatrachus robinmoorei) perches on a 0.94 inches (24 mm) rupee coin. This tiny fella measures 0.48 inches (12.2 mm) long.

Forest dweller

The Manalar Night Frog (Nyctibatrachus manalari) lives near tea plantations in the southern Western Ghats. This specimen measures 0.54 inches (13.8 mm).

Outside protected areas

Near tea plantations in the southern Western Ghats, the Manalar Night Frog (Nyctibatrachus manalari) resides in a fragmented forest patch.

Something on your nose

This miniature amphibian, a Manalar Night Frog (Nyctibatrachus manalari), lives in a fragmented forest patch in the Western Ghats, near private tea plantations.

Colorful family

The Sabarimala Night Frog (Nyctibatrachus sabarimalai) measures only 0.48 inches (12.3 mm). This minuscule amphibian makes its home near the Sabarimala Pilgrimage center in the Western Ghats.

Lots of neighbors

Researchers found the Athirappilly Night Frog (Nyctibatrachus athirappillyensis) near the Athirappilly waterfall in the Western Ghats, a site that is under consideration for a new hydroelectric project.

Threatened habitat

The Athirappilly Night Frog (Nyctibatrachus athirappillyensis) lives in a forest area threatened by human development.

New additions

A new study added seven night frog species from the Western Ghats to the amphibian family: A: Radcliffe's Night Frog; B: Athirappilly Night Frog; C: Kadalar Night Frog; D: Sabarimala Night Frog; E: Vijayan's Night Frog; F: Manalar Night Frog; G: Robin Moore's Night Frog.

New species

Would you like to cross paths with a hairy tarantula from Colombia or a Thai newt that looks like a "Star Trek" Klingon?

If the answer is yes, you're in good company. The researchers who discovered these previously unknown species were ecstatic to find and describe them to the scientific world, even as they spent countless hours detailing the characteristics and quirks of each animal in studies published this year.

Here are 10 incredible species that researchers discovered in 2016, and cool science facts about each one.

Mysterious Tully monster

A fossil discovered in Illinois in 1958 was so bizarre that researchers dubbed it the Tully Monster, naming it after Francis Tully, the amateur collector who found it.

In the following decades, some experts wondered whether it was a worm, while others made the case that it was a shell-less snail. Now, after studying 1,200 Tully monster (Tullimonstrum gregarium) specimens, researchers have found that the so-called monster is actually a 307-million-year-old jawless fish.

The 1-foot-long (0.3 m) creature had large eyes and pointy teeth, indicating it was a fearsome predator in its day, the scientists said. [Read the full story on the Tully monster]

Horse-size T. rex cousin

The horse-size cousin of Tyrannosaurus rex was not as big as the mighty dinosaur king, but it had a surprisingly advanced brain for its small stature, paleontologists announced this year.

Researchers studied the 90-million-year-old dinosaur's braincase (the area where the brain sits in the skull), which they discovered in modern-day Uzbekistan. The tyrannosaur (Timurlengia euotica) had remarkable low-frequency hearing, which likely helped it hunt prey, they said.

This finding suggests that tyrannosaurs likely got smart before they got big, and that both their size and smarts likely helped them become apex predators. [Read the full story on the brainy tyrannosaur]

Rare black whale

It took years, but scientists finally realized that a rarely seen whale isn't merely a dwarf or a juvenile common Baird's beaked whale (Berardius bairdii), but an entirely new species.

One of the clues that gave it away was its size. The elusive whale, which lives in the North Pacific, is 24 feet long (7 meters), smaller than the 40-foot (12 m) Baird's beaked whale. What's more, the Baird's whale is slate gray, and the newfound whale is black, earning it the nickname "karasu," the Japanese word for "raven."

A genetic study confirmed that the karasu is a previously unknown species. However, it is related to the Baird's whale, meaning that the two share a common ancestor, the researchers said. [Read the full story on the rare whale]

Wasteland frog

A teeny-tiny, newly identified species of frog sounds exactly like a cricket, researchers reported this year. The amphibian is so small that it can easily fit on a person's thumbnail. Perhaps that's why researchers didn't find the frog, which lives in the southwestern plains of India, until now.

Scientists named the frog Microhyla laterite, and noted that it lives on rocky terrain that the government defines as a "wasteland." But despite this classification, the wasteland is an incredible hotspot for biodiversity, the researchers said. [Read the full story on the tiny frog]

Peacock spiders

Peacock spiders may be tiny, but many people see them as big celebrities in the arachnid world. In 2015, the discovery of the black-and-white "Skeletorus" and the red-and-blue "Sparklemuffin" stole people's hearts — largely because of their colorful markings and intricate courtship dances.

This year, researchers found even more of these colorful spiders in Australia — seven in all — revealing that there are at least 48 species of peacock spider in the genus Maratus. All of the newfound spiders are no larger than 0.2 inches (5 millimeters), including Maratus bubo, so named because it reminded the scientists of an owl's face. (Bubo is the genus name for the great horned owl.) [Read the full story on the newfound peacock spiders]

Klingon newt

The Klingons from "Star Trek" have perpetually furrowed brows, which prompted scientists to nickname a newfound species of newt with a bumpy forehead in their honor.

The newt (Tylototriton anguliceps) is one of 163 previously undescribed species that live in Southeast Asia in an area encompassing Vietnam, Thailand, Cambodia, Laos and Myanmar, according to a 2016 World Wildlife Fund report.

Other newfound animals in the report include an iridescent snake (Parafimbrios lao) and other amphibians, reptiles, plants and mammals. The researchers urged policymakers to protect these animals, as many of the newfound species live in habitats threatened by human development. [Read the full story on the Klingon newt and the other newly described critters]

Muddy dinosaur

A bird-like dinosaur — complete with feathers, skinny legs and a bony crest on top of its head — met an unfortunate end about 66 million years ago, when it got stuck in the mud.

"The posture of the animal — the head is standing up, the neck is arched, the arms are spread out to the sides — it looks like it's trying to free itself," study co-researcher Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland, told Live Science in November. "Those signs make us think that it was stuck in mud and trying to get out."

The researchers detailed the extraordinary newfound species (Tongtianlong limosus) in the journal Scientific Reports. They noted that although the donkey-size dinosaur had feathers, it couldn't fly. But its anatomy revealed that it had other impressive abilities. For instance, its sharp beak likely helped it eat shellfish, plants, nuts and eggs in what is now China, the researchers said. [Read the full story on the bird-like dinosaur]

Márquez's tarantula

The Nobel Prize-winning author Gabriel García Márquez has a new fan, and that fan has eight legs. This past year, researchers named a newfound species of tarantula after Márquez because both the author and the spider are from Colombia, the researchers said.

The tarantula (Kankuamo marquezi) has unique "attack," or urticating, hairs, the researchers found. Most tarantulas "kick" their urticating hairs at enemies, but K. marquezi is the only known spider in its subfamily to use its hairs in direct contact confrontations, the researchers said.

Márquez died in 2014, so he never got to meet the tarantula. But now, when people read his books, including "100 Years of Solitude" and "Love in the Time of Cholera," perhaps they'll also think of the spider that carries his name. [Read the full story on the Márquez tarantula]

Small-brained titanosaur

The discovery of a previously unknown species of titanosaur — a ginormous, long-necked dinosaur that lived during the Cretaceous period about 95 million years ago — has helped researchers in a very cerebral way.

Usually, titanosaur fossils lack skulls. That wasn't the case with this newfound specimen, which was discovered in Patagonia; it had a braincase, as well as several neck vertebrae, the researchers said.

The team found that the previously unknown beast (Sarmientosaurus musacchioi) had extraordinary senses for its small brain. For instance, it had large eye sockets, indicating that it had good vision for spotting food, mates and predators. Moreover, the anatomy of its inner ear suggests it could hear low-frequency sounds, likely those made by other titanosaurs, the researchers said. [Read the full story on the small-brained titanosaur]

Ancient Muppet-faced fish

This year, researchers found not one, but two new species of Muppet-faced, prehistoric fish. The 92-million-year-old fish measured more than 6 feet (2 m) in length, and were likely filter feeders that slurped down plankton.

Researchers named the two newfound species Rhinconichthys purgatoirensis (discovered in Colorado) and R. uyenoi (discovered in Japan). There's only one other known species of this fish (R. taylori), which scientists found in England in 2010. These findings suggest that fish in the genus Rhinconichthys lived all over the world, the researchers said.

The Rhinconichthys genus came to an abrupt end about 66 million years ago, when an asteroid slammed into Earth and killed the nonavian dinosaurs, the researchers said. [Read the full story on the Muppet-faced fish]

Local folklore in the Amazon region and in parts of Central America claims that the bushmaster — a giant and deadly viper — can "sing." The breathy, repetitive notes of this call are associated with the venomous snake, and they instill fear in people living in the northwestern Amazon River basin, researchers have reported.

But scientists recently discovered who was really doing the singing.

In fact, more than one vocalist is responsible. The song attributed to the bushmaster turned out to belong to two types of tree frog: the little-known species Tepuihyla tuberculosa and a new species, Tepuihyla shushupe, whose name "shushupe" comes from the local term for the so-called "singing snake." [40 Freaky Frog Photos]

The scientists were researching frog populations in Ecuador and Peru when they learned of the alleged singing ability of the viper Lachesis muta from their field assistants, the researchers wrote in a new study.

Ironically, the second part of the snake's scientific name, "muta," means "voiceless."

But when the researchers investigated the sound identified by others as the viper's call, they instead tracked the call to two frog species. The researchers heard and analyzed a number of calls and obtained one T. shushupe individual, an adult male, in Peru's Putumayo River basin, close to the border shared with Colombia. From the calling behavior — which emanated from tree holes — the scientists interpreted that the frog lived in the canopy and descended into tree holes to breed.

T. shushupe and T. tuberculosa bothmeasure about 3 inches (85 millimeters) in length, which is large for this genus. Tepuihyla frogs typically reach about 2 inches (59 mm) in length. The study authors described the frogs' call as "a cackle of short notes repeated at a fast rate," with the amplitude and speed of the call building up during the first half and then decreasing toward the end.

So much for the local legends about the bushmaster's vocal prowess. However, some serpents can produce other types of unexpected noises.

King cobras are known to "growl" when agitated, producing the sound by resonating chambers in their tracheas, according to a December 1991 study published in the Journal of Experimental Zoology. And several species of snakes employ a defensive strategy known as "cloacal popping" — sometimes referred to as "microfarts" — made by expelling air from a vent in the cloaca, an opening at the rear of the body for the digestive and reproductive tracts.

It is unclear why the bushmaster was credited for the frogs' calls, but the researchers noted that the tale of the singing viper was widespread — and not just among people native to the Amazon basin. According to the authors, an earlier study reported that hunters and colonists shared similar stories about the viper's vocal abilities. Perhaps future investigations could get to the bottom of how people came to believe that a snake could sing, the study authors suggested.

The findings were published online Nov. 9 in the journal ZooKeys.

Original article on Live Science.

When it's just too darn hot, amphibian young adapt by changing their diet, weathering heat with vegetarian fare.

In a new study, tadpoles representing three frog species were exposed to mock "heat waves" in the laboratory to test how amphibians in the wild might respond to warmer-than-average conditions due to climate change.

When temperatures rose, so did the tadpoles' preference for vegetarian menus, the researchers found; the tadpoles consumed more plant-based meals when the controlled environments were hotter. [40 Freaky Frog Photos]

Scientists are particularly interested in how the dietary needs of amphibians and other ectotherms, or "cold-blooded animals" — those that use external sources to regulate body temperature — may be affected by a warming world, the researchers wrote in the study. Changes in temperature can affect how efficiently ectotherms process their food, and shifting to a more plant-based diet could help them compensate for those metabolic changes, the researchers said.

As climate change is spawning more frequent and more intense heat waves, the researchers wanted to see if amphibian young — tadpoles — would change their diets when exposed to artificial "heat waves."

In the study, the first to explore temperature-related diet changes in vertebrates, the scientists looked at three frog species that were native to the Iberian Peninsula in southwest Europe. The researchers collected eggs belonging to the Iberian painted frog (Discoglossus galganoi), the European tree frog (Hyla arborea) and the Mediterranean tree frog (Hyla meridionalis). The eggs were installed and hatched in aquariums in a laboratory.

In the experiment, the researchers gradually heated up the tadpoles' watery homes for periods lasting from one week to two months, to simulate how pond habitats might warm during a naturally occurring heat wave. They provided the growing tadpoles with meals of insect larvae and plant stalks, and then observed what the tadpoles ate and how their health and growth were affected.

"Normal" water temperature for the tadpoles was established at 70 degrees Fahrenheit (21 degrees Celsius), but then things heated up — temperatures sometimes rose as high as 77 degrees Fahrenheit (25 degrees Celsius) for days at a time. Although the three species had somewhat different diets, all consumed a higher percentage of plants, perhaps because they could process them more quickly, study co-author Germán Orizaola, a researcher in the Department of Ecology and Genetics at Uppsala University in Sweden, told Live Science in an email.

"Vegetarian diets are easily assimilated by animals under warm conditions — much easier than protein-rich animal diets," Orizaola said.

This is the first evidence that higher temperatures could drive ectotherms to increase their plant intake, and the first study to show this degree of flexibility in diets as animals adapt to climate change, the authors wrote.

But it also hints at how ecosystems — and the dietary needs of their inhabitants — could change in a warming world. Orizaola explained that if more amphibians require algae and plants to survive, the availability of those resources goes down, which, in turn, can affect other animals and even reduce water quality.

"This study provides us with information about how to manage freshwater environments exposed to the challenges of climate change," he added.

The findings were published online today (Nov. 3) in the journal Ecology.

Original article on Live Science.

SALT LAKE CITY — Long before dinosaurs walked the Earth, a teeny-tiny amphibian swam around a lake surrounded by large mountain ranges, using its minuscule jaws to nab insects and other small prey, a new study finds. 

The amphibian was still in its larval stage when it died (in frogs, this creature's distant relatives, the larval phase is known as the tadpole stage), and it expired on its back, belly-up, said study lead researcher Johan Gren, a doctoral student of geology at Lund University in Sweden.

The upper half of the body of this 295-million-year-old amphibian was exceptionally well preserved, the researchers found. For instance, most of the skull and braincase are present, as are several vertebrae, one of its front limbs, part of its lower jaw and some of its soft tissues, including a blackish film within its left eye socket, Gren said.  [In Photos: Giant Amphibian Ruled Ancient Rivers]

The teeny creature, just 1.5 inches (4 centimeters) long, is a temnospondyl, a group of early four-legged amphibians that are now extinct, and ranged in size from tiny to giant, Gren said. Had it lived to adulthood, the newly identified temnospondyl "could have grown to tens of centimeters," or maybe 8 to 12 inches, he noted.

Researchers discovered the fossil about 15 years ago in the Saar-Nahe Basin, located in southwestern Germany. The region is known for its many fossils; scientists also have found invertebrates, cartilaginous and bony fishes, and other amphibians in the area, which was once filled with numerous lakes that rippled between two mountain chains, Gren said.

Though tiny, the temnospondyl got star treatment: High-powered microscopes revealed a preserved layer of soft tissues outlining the amphibian's body, and computed tomography (CT) provided the scientists with a 3D image of the fossil, Gren said.

Gren and his adviser, Johan Lindgren, a senior lecturer of lithosphere and biosphere science at Lund University, plan to continue to study the "early frog relative," Gren said. He presented the unpublished findings Wednesday (Oct. 26) here at the 2016 meeting of the Society of Vertebrate Paleontology.

Original article on Live Science.

More than 10,000 endangered frogs and other water-dwelling animals living near a lake in South America were found mysteriously dead this month, according to reports from Peru’s wildlife and forestry service Serfor, leaving many people to wonder what could have caused this bizarre die-off.

The Titicaca water frog (Telmatobius culeus), also known as the "scrotum frog" for its loose skin, is one of the most critically endangered frogs in the world. The large, entirely aquatic frog adapted to the high altitudes of Lake Titicaca, which flows along the border between Bolivia and Peru, by taking in oxygen through its skin folds. This evolutionary adaptation also makes the frog highly sensitive to changes in its habitat, such as environmental contamination, according to Tom Weaver, curator of reptiles and fish at the Denver Zoo.

Researchers are currently investigating the latest massive die-off, which they think may have been caused by some sort of contamination. In 2014, an algae bloom that removed oxygen from the water, killed a number of frogs and fish, Weaver said. [5 Mysterious Animal Die-Offs]

"We're collecting more samples to find out what's causing this, because it could potentially be a disease outbreak or a contamination outbreak," Weaver told Live Science. "When you have an estimated 10,000 frogs die off, then it's usually a contamination of some sort."

The Denver Zoo has been involved in an effort to save the Titicaca water frog for nearly a decade. Researchers at the zoo have previously worked with authorities in South America when such large die-offs occur, and are again collaborating in research on the current die-off.

Weaver said the Denver Zoo team doesn't hear about every incident but that these die-offs are occurring more often, which suggests that the lake and surrounding rivers are perhaps being impacted by infrastructure development and contamination in the area.

"This is not something that happened just yesterday," Weaver said of the die-off at Lake Titicaca. "It's been going on for a while and is probably still going on right now. Everything else is dying in the lake — the fish — and it's affecting the whole chain — the whole ecosystem." [Photos: America's Only Lake Titicaca Frogs]

The rainy season has begun in the area, and Weaver said this may have triggered the movement of contaminants, such as human sewage and heavy metal pollution, toward the lake. He noted that locals say more amphibian and fish deaths occur during the rainy season.

In a blog post, Roberto Elias, Peru field program manager for the Denver Zoo, wrote about the infrastructure and waste that has contaminated the water and may have led to the frogs' deaths. Many of the deaths were noted along the Coata River, a tributary of Lake Titicaca. This river serves as a water source for several villages in the region, but it is also used as "landfill" by local people, according to Elias. 

"In the past, there have been complaints due to high pollution" including solid waste seen along the river, Elias wrote in the post. "This can be harmful to human and animal health, and is seen to a greater degree in species more susceptible such as fish and amphibians."

For the Titicaca water frog, these incidents are incredibly harmful because the amphibian is considered "critically endangered" according to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, which assesses species' conservation status. Over 15 years, more than 80 percent of the Titicaca water frog population has disappeared due to overexploitation, habitat degradation and invasive species, the IUCN said.

"It's devastating; the species is already struggling to begin with, and this is a bigger hit to it," Weaver said. "Whether or not the populations come back in these areas is yet to be seen."

Original article on Live Science.