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Painting Frogs, Licking Wounds & Other Adventures with Poisonous Animals

Wikimedia Commons
Wikimedia Commons

In the current issue of the magazine, I’ve got an article called “Fifty Shades of Prey,” about poison dart frogs and some new research into why they come in so many dazzling colors and patterns. 

I was drawn to the story not only because of what Canadian biologist Mathieu Choteau discovered about these frogs (which is pretty cool all by itself), but also by all the stuff he went through along the way. His research involved hand-molding and painting several thousand fake frogs with the help of his girlfriend, getting them on a plane to Peru (worried what airport security might say when they opened his bag), and then painstakingly pinning them to leaves while trudging through the rainforest. 

Going back even further into what we know about dart frogs and other poisonous animals, there are plenty of other intrepid scientists and strange sounding field work. I couldn’t fit all of their stories into the magazine piece, so I wanted to share a little bit about two of them here. 

The first is a guy named John W. Daly. In the early 1960s, not long after he took a job at the National Institutes of Health, he was sent on a research errand by the head of his lab. Certain native tribesmen in Colombia were known to coat the tips of their hunting arrows and blowgun darts with skin secretions from local frogs, which gave the weapons a toxic punch. The senior scientist wanted someone to go down to the rainforest, harvest some frogs, and analyze the chemicals in their skin. He’d been unable to find someone in the lab, though, who 1) had experience in the field and could handle a trip to the rainforest, and 2) he could afford to commit to research that might not pan out. 

Daly fit the bill perfectly. He was a chemist by training, but always had an interest in biology. He’d grown up in Oregon collecting frogs, snakes, and lizards and keeping them in his own little zoo in the basement. He was also young and a new hire, so they could get away with paying less for the field work than the other scientists. 

Daly was soon in the Amazon collecting frogs for a $16 per diem. Without many resources to work with, he developed an unusual way to figure out which frogs were worth examining and which weren’t. He’d slide a finger along a frog's skin, and then touch his tongue. If he experienced a burning sensation in his mouth, then the frog was worth a look. Fortunately, Daly took the locals’ advice about one particular frog. Even experienced tribal hunters only handled Phyllobates terribilis with the utmost care—it’s the most poisonous of the dart frogs and may be the most poisonous vertebrate in the world. 

Daly’s time tasting frogs in the rainforest eventually led to the discovery of the batrachotoxins (“frog poison”), the class of alkaloid poisons that make some of these frogs so deadly. In the early 1970s, Daly and colleagues published the chemical structure of the toxin and detailed its biological effects. 

Almost 20 years later and thousands of miles away, John Dumbacher, a grad student at the University of Chicago, was studying the courtship and mating behaviors of the Raggiana Bird-of-paradise in Papua New Guinea. He and his research team stretched nets between trees to capture the birds for study, and sometimes caught other birds by accident. Some of these were songbirds known as Hooded Pitohuis

As Dumbacher tried to free these birds, they’d bite or scratch at his hands and sometimes he would get cut. Rather than stopping his work and finding a place to wash his wounds, he would usually just pop the injured finger in his mouth to give the cut a quick clean. Just a few minutes later, though, his tongue and lips would start to tingle and burn a little. The sensation wasn’t awful—Dumbacher has compared it to eating a chili pepper or touching your tongue to a 9-volt battery—but it was puzzling, and after another student experienced the same thing, Dumbacher began to wonder if it was the bird’s fault. 

The next time a pitohui got caught in one of the nets, Dumbacher and the other student tasted one of the feathers. Sure enough, their mouths started to tingle and burn. They asked a few of the team’s forest guides about it and learned that the locals called the pitohuis “rubbish birds” or “garbage birds” and wouldn’t eat them, unless they were skinned and specially prepared for safety and flavor. The birds, Dumbacher realized, might be poisonous. 

While poisonous birds were sometimes rumored to exist, none had ever been scientifically confirmed, and the idea wasn’t always considered legitimate. Dumbacher wanted some pitohui feathers analyzed for toxins, but couldn’t find a chemist who would take his hypothesis seriously. Dumbacher returned to the U.S. with a bunch of feathers in 1990. Knowing about Daly’s experience with poisonous vertebrates, he called the NIH, a little bit worried that Daly would laugh him off as “just a nutty kid.” 

Daly was curious, though, and took the feathers and began to run some tests. When he took extracts from the feather and injected them into a mouse, it began to convulse and quickly died. He called Dumbacher back looking for more samples from the birds—the young man seemed to be onto something. 

Daly eventually isolated what he believed to be the toxic compound and had a colleague run a chemical analysis on it. When the colleague called him with the compound’s analysis, Daly recognized the characteristics and patterns immediately. It was the same chemical he’d found, identified, described, and named decades earlier. Batrachotoxin, the “frog poison,” had turned up in a bird.

Daly, Dumbacher, and their colleagues announced their discovery two years later in a paper in Science, and the hooded pitohui became the first confirmed poisonous bird. A decade later, the blue-capped ifrita became the second

What was frog poison doing in two different types of birds? How could the frogs and birds, separated by vast oceans and so many twists and turns of evolutionary history, produce the same toxin—not a similar toxin, but the exact same one?

More than a decade of work by Dumbacher, Daly and other researchers suggests that these odd, toxic bedfellows get their toxins from their diets. In Papua New Guinea, Dumbacher heard reports from locals of a few types of beetle that caused tingling and burning sensations on contact. He found those same beetles in the stomachs of the pitohuis and later found that they contained high concentrations of batrachotoxin. In a 2004 paper, he suggested that the bugs provided a natural toxin source for the birds, and that other bugs might do the same for poison dart frogs. 

Daly had touched on the same idea before, noticing that a change in the frogs’ diet altered their toxic profile. Around the same time as Dumbacher’s study, Daly and colleagues from the NIH and elsewhere found evidence that ants and “moss mites” in Central America contained some of the same alkaloids as the frogs and made up a large portion of their diet. This second study supporting the toxic diet idea was one of the last papers Daly published before his death in 2008. 

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Christine Colby
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13 Secrets From the Ravenmaster at the Tower of London
Christine Colby
Christine Colby

Christopher Skaife is a Yeoman Warder at the Tower of London, an ancient fortress that has been used as a jail, royal residence, and more. There are 37 Yeoman Warders, popularly known as Beefeaters, but Skaife has what might be the coolest title of them all: He is the Ravenmaster. His job is to maintain the health and safety of the flock of ravens (also called an “unkindness” or a “conspiracy”) that live within the Tower walls. According to a foreboding legend with many variations, if there aren’t at least six ravens living within the Tower, both the Tower and the monarchy will fall. (No pressure, Chris!)

Skaife has worked at the Tower for 11 years, and has many stories to tell. Recently, Mental Floss visited him to learn more about his life in service of the ravens.

1. MILITARY SERVICE IS REQUIRED.

All Yeoman Warders must have at least 22 years of military service to qualify for the position and have earned a good-conduct medal. Skaife served for 24 years—he was a machine-gun specialist and is an expert in survival and interrogation resistance. He is also a qualified falconer.

Skaife started out as a regular Yeoman Warder who had no particular experience with birds. The Ravenmaster at the time "saw something in him," Skaife says, and introduced him to the ravens, who apparently liked him—and the rest is history. He did, however, have to complete a five-year apprenticeship with the previous Ravenmaster.

2. HE LIVES ON-SITE.

The Tower of London photographed at night
Christine Colby

As tradition going back 700 years, all Yeoman Warders and their families live within the Tower walls. Right now about 150 people, including a doctor and a chaplain, claim the Tower of London as their home address.

3. BUT HE’S HAD TO MOVE.

Skaife used to live next to the Bloody Tower, but had to move to a different apartment within the grounds because his first one was “too haunted.” He doesn’t really believe in ghosts, he says, but does put stock in “echoes of the past.” He once spoke to a little girl who was sitting near the raven cages, and when he turned around, she had disappeared. He also claims that things in his apartment inexplicably move around, particularly Christmas-related items.

4. THE RAVENS ENJOY SOME UNUSUAL SNACKS.

The Ravenmaster at the Tower of London bending down to feed one of his ravens
Christine Colby

The birds are fed nuts, berries, fruit, mice, rats, chicken, and blood-soaked biscuits. (“And what they nick off the tourists,” Skaife says.) He has also seen a raven attack and kill a pigeon in three minutes.

5. THEY GET A LULLABY.

Each evening, Skaife whistles a special tone to call the ravens to bed—they’re tucked into spacious, airy cages to protect them from predators such as foxes.

6. THERE’S A DIVA.

One of the ravens doesn’t join the others in their nighttime lodgings. Merlina, the star raven, is a bit friendlier to humans but doesn’t get on with the rest of the birds. She has her own private box inside the Queen’s House, which she reaches by climbing a tiny ladder.

7. ONE OF THEM HAS EARNED THE NICKNAME “THE BLACK WIDOW.”

Ravens normally pair off for life, but one of the birds at the Tower, Munin, has managed to get her first two mates killed. With both, she lured them high atop the White Tower, higher than they were capable of flying down from, since their wings are kept trimmed. Husband #1 fell to his death. The second one had better luck coasting down on his wings, but went too far and fell into the Thames, where he drowned. Munin is now partnered with a much younger male.

8. THERE IS A SECRET PUB INSIDE THE TOWER.

Only the Yeoman Warders, their families, and invited guests can go inside a secret pub on the Tower grounds. Naturally, the Yeoman Warder’s Club offers Beefeater Bitter beer and Beefeater gin. It’s lavishly decorated in police and military memorabilia, such as patches from U.S. police departments. There is also an area by the bar where a section of the wall has been dug into and encased in glass, showing items found in an archaeological excavation of the moat, such as soldiers’ discarded clay pipes, a cannonball, and some mouse skeletons.

9. … AND A SECRET HAND.

The Byward Tower, which was built in the 13th century by King Henry III, is now used as the main entrance to the Tower for visitors. It has a secret glass brick set into the wall that most people don’t notice. When you peer inside, you’ll see it contains a human hand (presumably fake). It was put in there at some point as a bit of a joke to scare children, but ended up being walled in from the other side, so is now in there permanently.

10. HE HAS A SIDE PROJECT.

Skaife considers himself primarily a storyteller, and loves sharing tales of what he calls “Victorian melodrama.” In addition to his work at the Tower, he also runs Grave Matters, a Facebook page and a blog, as a collaboration with medical historian and writer Dr. Lindsey Fitzharris. Together they post about the history of executions, torture, and punishment.

11. THE TOWER IS MUPPET-FAMOUS.

2013’s Muppets Most Wanted was the first major film to shoot inside the Tower walls. At the Yeoman Warder’s Club, you can still sit in the same booth the Muppets occupied while they were in the pub.

12. IF YOU VISIT, KEEP AN EYE ON YOUR MONEY.

Ravens are very clever and known for stealing things from tourists, especially coins. They will strut around with the coin in their beak and then bury it, while trying to hide the site from the other birds.

13. … AND ON YOUR EYES.

Skaife, who’s covered in scars from raven bites, says, “They don’t like humans at all unless they’re dying or dead. Although they do love eyes.” He once had a Twitter follower, who is an organ donor, offer his eyes to the ravens after his death. Skaife declined.

This story first ran in 2015.

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15 Reasons You Should Appreciate Squirrels
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iStock

Even if you live in a big city, you probably see wildlife on a regular basis. Namely, you're sure to run into a lot of squirrels, even in the densest urban areas. And if you happen to live on a college campus, well, you're probably overrun with them. While some people might view them as adorable, others see them as persistent pests bent on chewing on and nesting in everything in sight. But in honor of National Squirrel Appreciation Day, here are 15 reasons you should appreciate the savvy, amazing, bushy-tailed critters.

1. THEY CAN JUMP REALLY, REALLY FAR.

A flying squirrel soars through the air
iStock

In one study [PDF] of the tree-dwelling plantain squirrels that roam the campus of the National University of Singapore, squirrels were observed jumping almost 10 feet at a stretch. In another study with the eastern ground squirrel, one researcher observed a squirrel jumping more than 8 feet between a tree stump and a feeding platform, propelling itself 10 times the length of its body. Flying squirrels, obviously, can traverse much farther distances midair—the northern flying squirrel, for instance, can glide up to 295 feet [PDF].

2. THEY'RE VERY ORGANIZED …

A squirrel digs in a grassy field filled with fallen leaves.
iStock

In fact, they may be more organized than you are. A recent study found that eastern fox squirrels living on UC Berkeley's campus cache their nuts according to type. When given a mixture of walnuts, pecans, almonds, and hazelnuts, the squirrels took the time to hide each type of nut in a specific place. This method of "spatial chunking" may help them remember where the nuts are when they go to retrieve them later. Though the study wasn't able to determine this for sure, the study's results suggested that the squirrels may have been organizing their caches by even more subtle categories, like the size of the nuts.

3. … BUT THEIR FORGETFULNESS HELPS TREES GROW.

Looking up a tree trunk at a squirrel climbing down
iStock

Tree squirrels are one of the most important animals around when it comes to planting forests. Though they may be careful about where they bury their acorns and other nuts, they still forget about quite a few of their caches (or at least neglect to retrieve them). When they do, those acorns often sprout, resulting in more trees—and eventually, yet more acorns for the squirrels.

4. THEY HELP TRUFFLES THRIVE.

A man holds a truffle up for the camera.
iStock

The squirrel digestive system also plays an important role in the survival of truffles. While above-ground mushrooms can spread their spores through the air, truffles grow below ground. Instead of relying on the air, they depend on hungry animals like squirrels to spread their spores to host plants elsewhere. The northern flying squirrel, found in forests across North America, depends largely on the buried fungi to make up its diet, and plays a major role in truffle propagation. The squirrels poop out the spores unharmed on the forest floor, allowing the fungi to take hold and form a symbiotic relationship with the tree roots it's dropped near.

5. THEY'RE ONE OF THE FEW MAMMALS THAT CAN SPRINT DOWN A TREE HEAD-FIRST.

A squirrel stands on the knot of a tree trunk looking down at the ground.
iStock

You may not be too impressed when you see a squirrel running down a tree, but they're actually accomplishing a major feat. Most animals can't climb vertically down head-first, but squirrel's back ankles can rotate 180°, turning their paws all the way around to grip the tree trunk as they descend.

6. SEVERAL TOWNS COMPETE FOR THE TITLE OF 'HOME OF THE WHITE SQUIRREL.'

A white squirrel in Olney, Illinois stands on its hind legs.
iStock

Squirrels are a more popular town mascot than you might think. Surprisingly, more than one town wants to be known as the "home of the white squirrel," including Kenton, Tennessee; Marionville, Missouri; the Canadian city of Exeter, Ontario; and Brevard, North Carolina, the location of the annual White Squirrel Festival. But Olney, Illinois may be the most intense about its high population of albino squirrels. There is a $750 fine for killing the all-white animals, and they have the legal right-of-way on roads. There's an official city count of the squirrels each year, and in 1997, realizing that local cats posed a threat to the beloved rodent residents, the city council banned residents from letting their cats run loose outdoors. In 2002, the city held a 100-Year White Squirrel Celebration, erecting a monument and holding a "squirrel blessing" by a priest. Police officers wore special squirrel-themed patches for the event.

7. THEY CAN AID STROKE RESEARCH.

An illustration of different regions of the brain lighting up in blue
iStock

Ground squirrels hibernate in the winter, and the way their brains function while they do may help scientists develop a new drug that can limit the brain damage caused by strokes. When ground squirrels hibernate, their core body temperature drops dramatically—in the case of the arctic ground squirrel, to as low as 26.7°F, possibly the lowest body temperature of any mammal on Earth. During this extra-cold hibernation, a squirrel's brain undergoes cellular changes that help its brain deal with reduced blood flow. Researchers are currently trying to develop a drug that could mimic that process in the human brain, preventing brain cells from dying when blood flow to the brain is cut off during a stroke.

8. THEIR FUR MAY HAVE SPREAD LEPROSY IN THE MIDDLE AGES.

A woman in a fur vest with a hood faces away from the camera and stares out over the water.
iStock

If you always warn your friends not to pet or feed squirrels because they can spread disease, put this story in your back pocket for later: They may have helped leprosy spread from Scandinavia to the UK in the 9th century. Research published in 2017 found a strain of leprosy similar to a modern variant found in squirrels in southern England in the skull of a woman who lived in England sometime between 885 and 1015 CE. The scientists suggest that the leprosy may have arrived along with Viking squirrel pelts. "It is possible that this strain of leprosy was proliferated in the South East of England by contact with highly prized squirrel pelt and meat, which was traded by the Vikings at the time this woman was alive," one of the authors told The Guardian. That may not be the most uplifting reason to appreciate squirrels, but it's hard not to admire their influence!

9. THEY'RE MORE POWERFUL THAN HACKERS.

A squirrel runs across a power line.
Frederic J. Brown, AFP/Getty Images

While energy companies may worry about hackers disrupting the power grid, squirrels are actually far more powerful than cyber-whizzes when it comes to sabotaging our electricity supply. A website called Cyber Squirrel 1 documents every public record of squirrels and other animals disrupting power services dating back to 1987. It has counted more than 1100 squirrel-related outages across the world for that time period, which is no doubt a vast underestimate. In a 2016 survey of public power utilities, wildlife was the most common cause of power outages, and for most power companies, that tends to mean squirrels.

10. THEY CAN HEAT UP THEIR TAILS TO WARD OFF PREDATORS.

A ground squirrel sits with its mouth open.
David McNew, Getty Images

California ground squirrels have an interesting way of scaring off rattlesnakes. Like cats, their tails puff up when they go on the defense. A squirrel will wave its tail at a rattlesnake to convince the snake that it's a formidable opponent. Surprisingly, they whip their tails at their foes whether it's light or dark outside. Squirrels can control the blood flow to their tails to cool down or keep warm, and they use this to their advantage in a fight, pumping blood into their tails. Even if the rattlesnakes can't see the bushy tails, researchers found in 2007, they can sense the heat coming off them.

11. THEY HELP SCIENTISTS KNOW WHETHER A FOREST IS HEALTHY.

A squirrel runs down a tree trunk toward a pile of leaves.
iStock

Researchers look at tree squirrel populations to measure just how well a forest ecosystem is faring. Because they depend on their forest habitats for seeds, nesting sites, and food storage, the presence and demographics of tree squirrels in an area is a good bellwether for the health of a mature forest. Studying changes in squirrel populations can help experts determine the environmental impact of logging, fires, and other events that alter forest habitats [PDF].

12. THEY CAN LIE.

A squirrel with a bushy tail stands on its hind legs.
iStock

Gray squirrels know how to deceive. They can engage in what's called "tactical deception," a behavior previously only seen in primates, as a study in 2008 found. When they think they're being watched by someone looking to pilfer their cache of food, the researchers discovered, they will pretend to dig a hole as if burying their acorn or nut, but tuck their snack into their mouth and go bury it elsewhere.

13. THEY WERE ONCE AMERICA'S MOST POPULAR PET.

A man in a hat kisses a squirrel on the White House grounds
Harris & Ewing, Library of Congress // Public Domain

Though some states currently ban (or require permits for) keeping squirrels as pets, it was once commonplace. Warren G. Harding kept a squirrel named Pete who would sometimes show up to White House meetings and briefings, where members of Harding's cabinet would bring him nuts. But keeping a squirrel around wasn't just for world leaders—the rodent was the most popular pet in the country, according to Atlas Obscura. From the 1700s onwards, squirrels were a major fixture in the American pet landscape and were sold in pet shops. Despite Harding's love of Pete, by the time he lived in the White House in the 1920s, squirrel ownership was already on the wane, in part due to the rise of exotic animal laws.

14. THE MERE SIGHT OF JUST ONE COULD ONCE ATTRACT A CROWD.

A historical photo of nurses leaning down to feed a black squirrel
Library of Congress // Public Domain

The American cities of the 1800s weren't great places to catch a glimpse of wildlife, squirrels included. In fact, the animals were so rare that in the summer of 1856, when a gray squirrel escaped from its cage inside a downtown New York apartment building (where it was surely living as someone's pet), it merited a write-up in The New York Times. According to the paper, several hundred people gathered to gawk at the tree where the squirrel took refuge and try to coax the rodent down. In the end, a police officer had to force the crowd to disperse. The paper did not document what happened to the poor squirrel.

15. IN THE 19TH CENTURY, THEY WERE TASKED WITH TEACHING COMPASSION.

A boy doing homework with a squirrel on the table.
Hulton Archive, Getty Images

In the mid-1800s, seeking to return a little bit of nature to concrete jungles, cities began re-introducing squirrels to their urban parks. Squirrels provided a rare opportunity for city slickers to see wildlife, but they were also seen as a sort of moral compass for young boys. Observing and feeding urban squirrels was seen as a way to steer boys away from their "tendency toward cruelty," according to University of Pennsylvania historian Etienne Benson [PDF]. Boy Scouts founder Ernest Thompson Seton argued in a 1914 article that cities should introduce "missionary squirrels" to cities so that boys could befriend them. He and other advocates of urban squirrels "saw [them] as opportunities for boys to establish trusting, sympathetic, and paternalistic relationships with animal others," Benson writes.

But young boys weren't the only ones that were thought to benefit from a little squirrel-feeding time. When the animals were first reintroduced to parks in the 19th century, feeding squirrels was considered an act of charity—one accessible even to those people who didn't have the means of showing charity in other realms. "Because of the presence of urban squirrels, even the least powerful members of human society could demonstrate the virtue of charity and display their own moral worth," Benson writes. "Gray squirrels helped reshape the American urban park into a site for the performance of charity and compassion for the weak." Even if you were too poor to provide any sort of charity for someone else, you could at least give back to the squirrels.

BONUS: THEY USED TO HATE TAX SEASON TOO.

A colored lithograph shows men and dogs hunting squirrels in a forest.
Currier and Ives, Library of Congress // Public Domain

Though notably absent from big cities, much of the U.S. was once overrun by squirrels. The large population of gray squirrels in early Ohio caused such widespread crop destruction that people were encouraged—nay, required—to hunt them. In 1807, the Ohio General Assembly demanded that citizens not just pay their regular taxes, but add a few squirrel carcasses on top. According to the Ohio History Connection, taxpayers had to submit a minimum of 10 squirrel scalps to the town clerk each year. Tennessee had similar laws, though that state would let people pay in dead crows if they couldn't rustle up enough squirrels.

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