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10 Neat Facts About Newts

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The subject of an unmade Pixar film and the occasional Monty Python joke—and a key ingredient in many a witch's brew—these little amphibians are world-class survivors. 

1. ONE SPECIES DEFENDS ITSELF WITH MOVABLE RIBS.

Pengo, WikimediaCommons // CC BY-SA 3.0

Prod a Spanish ribbed newt (Pleurodeles waltl) at your own risk. These flat-headed animals have a nasty surprise in store for wannabe predators: They can rotate their ribs forward so that they break through the skin, creating protective spikes. And that's not all: When the ribs break through, they're coated with a poison that is secreted simultaneously. Once danger passes, the ribs retract and the punctured skin starts to heal.

2. IN MEDIEVAL EUROPE, NEWTS WERE ASSOCIATED WITH EVIL SPIRITS.

Legend had it that witches could summon demons via a newt-based brandy. The Bard himself referenced this in Macbeth: Act IV opens with Shakespeare’s witches tossing such ingredients as “eye of newt and toe of frog” into their special brew.

3. SOME CAN RE-GROW THEIR EYE LENSES AT LEAST 18 TIMES.

That fact that most lizards can replace a lost tail is common knowledge, but newts make this talent look like a party trick: After losing a limb, they can grow another one in a matter of weeks.

Newts are also capable of regenerating tails, jaws, spinal cords, heart ventricles, and eyes. But can they do so indefinitely? Between 1994 and 2010, a team from University of Dayton tested the limits of this healing superpower. Over those 16 years, half a dozen Japanese newts (Cynops pyrrhogaster) had their eye lenses surgically removed 18 times apiece. The results were unbelievable: Not only did new lenses appear after every single extraction, but the replacements functioned just as well as the originals had.

According to Panagiotis Tsonis, who headed up the experiment, the discovery could have enormous medical implications. “We are still a long way from relating this to humans,” he told Wired UK, “but what this shows is that the newt is an excellent source for finding answers to regeneration.”

4. THE EASTERN NEWT (NOTOPHTHALMUS VIRIDESCENS) IS NEW HAMPSHIRE'S STATE AMPHIBIAN.

Raeky, Wikimedia Commons // CC BY 2.0

In 1985, New Hampshire became the first state to designate an official amphibian. Seventeen others have since done likewise, but they’ve all picked non-newts. Notophthalmus viridescens has a huge range extending from Canada to Florida and from New England to Kansas.

5. CERTAIN NEWTS WILL METAMORPHOSE TWICE.

Like most amphibians, newts start out as gilled, water-bound larvae that grow up into air-breathing adults. However, some actually assume an intermediate form. After leaving their larval stage, many species, like the eastern newt, become bumpy-skinned juveniles, or efts, adapted for life on dry land. A few years later, they return to the water as aquatic adults, complete with webbed feet and paddled tails.

6. AMOROUS MALES SECRETE REALLY POTENT PHEROMONES.

The key to a female newt’s heart is through her nostrils. When mating season rolls around, male Alpine (Ichthyosaurua alpestris) and palmate (Lissotriton helveticus) newts release a titillating cocktail of pheromones into the water to attract nearby females. The courtship ritual begins with a male waving its tail at a female, who then follows him around for a bit. When she's ready to mate, she touches her nose to his tail, and he deposits a spermatophore on a leaf or other surface; he'll lead her to it, and it will stick to her cloaca and eventually lead to insemination.

A 2011 experiment showed that the pheromones might work a little too well—in fact, the scent rendered captive females uncontrollably lustful. No males were present, so they started courting each other. “We were convinced that if we put in a plastic toy moving at the right speed, they would follow it,” said researcher Franky Bossuyt of Vrije Universiteit Brussel. 

7. SPANISH RIBBED NEWTS HAVE BECOME AMPHIBIOUS ASTRONAUTS. 

Between 1985 and 2005, six different missions sent Pleurodeles waltl into orbit. Astronomers keep choosing this species in part because of its superhuman healing ability. Does a brief stint in the final frontier affect the ribbed newt’s limb regeneration process? For the most part, the answer is no—except for when you launch one that’s currently growing a new leg. Being in space slows down the appendage’s development. But when the newt returns to Earth, the growth rate accelerates beyond what’s considered normal.

Scientists have also studied the effects of extraterrestrial travel on P. waltl embryonic development. Females give birth to live larvae and can keep sperm “on hold” inside their bodies for up to five months. When they detect the right hormone, the newts fertilize their eggs with this stored sperm. So we can observe P. waltl embryos that were actually conceived in outer space. Unfortunately, those fetuses are mostly deformed.

8. THEY MAKE BARELY AUDIBLE NOISES.

Newts may not be as vocal as frogs and toads, but if you listen closely, you just might hear them chatting. Eastern newts, for example, emit a faint “tic-tic-tic” sound. Meanwhile, California newts (Taricha torosa) will click while walking through unfamiliar terrain, squeak when handled, and ward off their rivals with a whistle.

9. A SINGLE ROUGH-SKINNED NEWT (TARICHA GRANULOSA) IS POISONOUS ENOUGH TO KILL AN ESTIMATED 25,000 MICE.

Rough-skinned newts may not look very threatening, but they’re some of the most dangerous animals on Earth. These natives of the American west coast produce a powerful substance called tetrodotoxin (TTX) that blocks the signals through which the victim’s brain communicates with the rest of its body. Numbness, dizziness, spasms, and paralysis ensue.

The TTX-filled skin of an average adult T. granulosa could potentially kill some 25,000 mice. Out in the wild, biologists have documented them killing 30 different types of vertebrates [PDF], including fish, great blue herons, and belted kingfishers. The newts give their predators fair warning, though: They advertise their toxicity by looking upwards and flashing their brightly colored throats. Most carnivores back off—though it looks like this bullfrog didn’t get the memo:

10. ROUGH-SKINNED NEWTS ARE IN A DEADLY ARMS RACE WITH THE COMMON GARTER SNAKE. 

Why is this species so ridiculously poisonous? Why does it wield enough TTX to kill 25,000 mice? Shouldn’t having a sufficient amount for, say, 15,000 be plenty?

Actually, it isn’t. For all its secretions, there’s one predator that the rough-skinned newt still fears: the common garter snake (Thamnophis sirtalis). Some populations of these serpents have enough TTX immunity to dine on the amphibians and live. Faced with this threat, the newts have responded by becoming even more toxic. Meanwhile, the snakes keep growing more TTX-resistant.

It currently looks like the reptiles may be winning. A few garters are now built to tolerate as much as 100 milligrams of TTX—almost 10 times more than what the newts can physically produce. But there’s a trade-off for the snakes: Highly resistant individuals are atypically slow—which makes them more vulnerable to their own predators. Who knows? Maybe the newts will get the last laugh.

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Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

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Animals
15 Confusing Plant and Animal Misnomers
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People have always given names to the plants and animals around us. But as our study of the natural world has developed, we've realized that many of these names are wildly inaccurate. In fact, they often have less to say about nature than about the people who did the naming. Here’s a batch of these befuddling names.

1. COMMON NIGHTHAWK

There are two problems with this bird’s name. First, the common nighthawk doesn’t fly at night—it’s active at dawn and dusk. Second, it’s not a hawk. Native to North and South America, it belongs to a group of birds with an even stranger name: Goatsuckers. People used to think that these birds flew into barns at night and drank from the teats of goats. (In fact, they eat insects.)

2. IRISH MOSS

It’s not a moss—it’s a red alga that lives along the rocky shores of the northern Atlantic Ocean. Irish moss and other red algae give us carrageenan, a cheap food thickener that you may have eaten in gummy candies, soy milk, ice cream, veggie hot dogs, and more.

3. FISHER-CAT

Native to North America, the fisher-cat isn’t a cat at all: It’s a cousin of the weasel. It also doesn’t fish. Nobody’s sure where the fisher cat’s name came from. One possibility is that early naturalists confused it with the sea mink, a similar-looking creature that was an expert fisher. But the fisher-cat prefers to eat land animals. In fact, it’s one of the few creatures that can tackle a porcupine.

4. AMERICAN BLUE-EYED GRASS

American blue-eyed grass doesn’t have eyes (which is good, because that would be super creepy). Its blue “eyes” are flowers that peek up at you from a meadow. It’s also not a grass—it’s a member of the iris family.

5. MUDPUPPY

The mudpuppy isn’t a cute, fluffy puppy that scampered into some mud. It’s a big, mucus-covered salamander that spends all of its life underwater. (It’s still adorable, though.) The mudpuppy isn’t the only aquatic salamander with a weird name—there are many more, including the greater siren, the Alabama waterdog, and the world’s most metal amphibian, the hellbender.

6. WINGED DRAGONFISH

This weird creature has other fantastic and inaccurate names: brick seamoth, long-tailed dragonfish, and more. It’s really just a cool-looking fish. Found in the waters off of Asia, it has wing-like fins, and spends its time on the muddy seafloor.

7. NAVAL SHIPWORM

The naval shipworm is not a worm. It’s something much, much weirder: a kind of clam with a long, wormlike body that doesn’t fit in its tiny shell. It uses this modified shell to dig into wood, which it eats. The naval shipworm, and other shipworms, burrow through all sorts of submerged wood—including wooden ships.

8. WHIP SPIDERS

These leggy creatures are not spiders; they’re in a separate scientific family. They also don’t whip anything. Whip spiders have two long legs that look whip-like, but that are used as sense organs—sort of like an insect’s antennae. Despite their intimidating appearance, whip spiders are harmless to humans.

9. VELVET ANTS

A photograph of a velvet ant
Craig Pemberton, Wikimedia Commons // CC BY-SA 3.0

There are thousands of species of velvet ants … and all are wasps, not ants. These insects have a fuzzy, velvety look. Don’t pat them, though—velvet ants aren’t aggressive, but the females pack a powerful sting.

10. SLOW WORM

The slow worm is not a worm. It’s a legless reptile that lives in parts of Europe and Asia. Though it looks like a snake, it became legless through a totally separate evolutionary path from the one snakes took. It has many traits in common with lizards, such as eyelids and external ear holes.

11. TRAVELER'S PALM

This beautiful tree from Madagascar has been planted in tropical gardens all around the world. It’s not actually a palm, but belongs to a family that includes the bird of paradise flower. In its native home, the traveler’s palm reproduces with the help of lemurs that guzzle its nectar and spread pollen from tree to tree.

12. VAMPIRE SQUID

Drawing of a vampire squid
Carl Chun, Wikimedia Commons // Public Domain

This deep-sea critter isn’t a squid. It’s the only surviving member of a scientific order that has characteristics of both octopuses and squids. And don’t let the word “vampire” scare you; it only eats bits of falling marine debris (dead stuff, poop, and so on), and it’s only about 11 inches long.

13. MALE FERN & LADY FERN

Early botanists thought that these two ferns belonged to the same species. They figured that the male fern was the male of the species because of its coarse appearance. The lady fern, on the other hand, has lacy fronds and seemed more ladylike. Gender stereotypes aside, male and lady Ferns belong to entirely separate species, and almost all ferns can make both male and female reproductive cells. If ferns start looking manly or womanly to you, maybe you should take a break from botany.

14. TENNESSEE WARBLER

You will never find a single Tennessee warbler nest in Tennessee. This bird breeds mostly in Canada, and spends the winter in Mexico and more southern places. But early ornithologist Alexander Wilson shot one in 1811 in Tennessee during its migration, and the name stuck.

15. CANADA THISTLE

Though it’s found across much of Canada, this spiky plant comes from Europe and Asia. Early European settlers brought Canada thistle seeds to the New World, possibly as accidental hitchhikers in grain shipments. A tough weed, the plant soon spread across the continent, taking root in fields and pushing aside crops. So why does it have this inaccurate name? Americans may have been looking for someone to blame for this plant—so they blamed Canada.

A version of this story originally ran in 2015.

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