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15 Islands Overrun by Cute Animals

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Strange things happen in island ecosystems, and occasionally—whether by accident, or design—a population of adorable creatures takes over. They draw tourists, can be a little spooky, and sometimes wreak havoc. But you have to admit: they are pretty cute. 

1. Ōkunoshima, Japan // Rabbits

Often called Usaga Jima, or Rabbit Island, this place was once a top-secret chemical weapons production site during World War II. Now it’s covered in bunnies. The Poison Gas Museum on Ōkunoshima doesn’t draw as many tourists as the hundreds of rabbits that now roam the streets freely and with little fear of humans (as you can see above). While some suspect the rabbits are descendants of test subjects from the chemical plant, the official story is that schoolchildren left them behind on a visit in the 1970s. With no natural predators on the island, they bred like, well, rabbits.

2. Kauai, Hawaiian Islands // Chickens


The Hawaiian islands are full of odd case studies of introduced species gone wild, but none as cute as the thousands of chickens on Kauai. The feral roosters, hens, and chicks have no natural predators on Kauai, so the population has spun out of control. (The mongooses that keep chickens on the other islands in check aren't found on Kauai.) These chickens have adapted to feed on cat food, garbage, scraps from tourists, and native bugs. 

Biologists have taken particular interest in them, as they aren’t your ordinary chickens. A recent genetic study indicates that they may actually be hybrids of chicken ancestors brought from Polynesia hundreds of years ago, and plain old domestic chickens that escaped during more recent hurricanes. 

3. Big Major Cay, The Bahamas // Pigs


Pigs big and small spend their days sleeping on the beach and splashing around in the blue waters of this tiny island in the Caribbean. About 20 pigs and piglets now live on the beach, and live at least in part on food from tourists, who frequent the island to swim with them. When a boat comes close to the pigs’ beach (Pig Beach), the animals routinely paddle out for food.

There are many origin stories about how their forebears got there—surviving a wreck, dumped by former owners from a nearby island, planted as a tourist draw. But they’ve been surviving and breeding for years now.

4. Tonawanda Island, New York // Cats


Dozens to hundreds of feral cats live on this island in the river to the north of Buffalo. The 85-acre chunk of land has become a dumping ground-turned-paradise for unwanted felines. While the thought of cats laying claim to their own island to live out their days might sound kind of idyllic, it’s actually a problem. As an island restaurant owner told the TV news, “there’s just too many cats is what it boils down to.”

One area woman made it her mission to get the population under control, raising $16,000 for the cause last year. Operation: Island Cats resulted in the trapping and spaying or neutering of 130 cats, and returning most of them to the island. Kittens were put up for adoption, but most adult cats had already tasted too much freedom.

5. Tashirojima, Japan // More Cats


There are actually about a dozen “cat islands” in Japan. The fishing village on Tashirojima is down to about 100 people, but has hundreds of cats. The story goes that the village once raised silkworms, and cats were introduced to prey on the mice that preyed on the worms. The population grew in the 1800s, as fishermen began to regard the cats as good luck. There are multiple shrines honoring the animals, and visitors can even stay at vacation homes shaped like cats and decorated by famous manga artists. 

6. Gough Island // House Mice


Mice can definitely be cute, but this particular tale takes an ugly turn. Sometime in the 1800s, a few tiny house mice wandered off a whaling ship onto an isolated island in the South Atlantic. Mice, which mostly scavenge for insects and seeds, are seemingly not the worst invasive species you could imagine. But then, the mice … changed. They’ve adapted to become top predators thanks to a horrifying trick they picked up—eating seabird chicks alive

While the chicks are much larger than the mice, they are basically defenseless, and their parents aren’t used to fighting off predators. As the mice became carnivorous, they’ve also grown to be much larger than a typical mouse. These giant killer mice have taken over the small island, endangering its rare seabirds, and leading researchers to plan an eradication program

7. New Zealand // Sheep


In 1982, New Zealand’s sheep population peaked at something like 22 sheep per person—that’s 70.3 million sheep versus 3.2 million people. That number has dropped significantly these days, due to changing markets, down to a meager 30 million sheep. But that’s still a high, six-to-one sheep-to-person ratio.

New Zealand’s sheep are no freak accident. They are a product of good-old-fashioned colonialism, first dropped off by British explorer James Cook in 1773. Sheep farming became the dominant agricultural industry in New Zealand for 130 years. 

8. Miyajima Island, Japan // Deer

Adam Clement

This small island in Hiroshima Bay has become a haven for deer, as has the city of Nara on the main island of Honshu. Deer populations are considered a pest in some regions of Japan, but they’ve become a draw at these spots. Hundreds of sika deer wander and lounge casually in the streets, where tourists feed them generously. The Nara deer have even picked up a trick—bow to one, and it will bow back in exchange for food.

9. Lambay Island, Ireland // Wallabies


About 9000 miles from their native Australia, a population of a few dozen wallabies can be seen bounding across this misty island in the Irish Sea. The small, furry relatives of the kangaroo are highly adaptable, and the rocky cliffs, while colder than they like, suit their inclination for rough terrain. The wallabies originally made it to Lambay when the banking family that owns the land decided to raise them in the 1950s and 1960s. The population grew when the Dublin Zoo had a wallaby surplus in the 1980s and introduced a handful on the island. 

10. Assateague Island, Maryland/Virginia // Ponies

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Famed wild ponies play in the surf on this long and narrow barrier island. They’re actually not wild or ponies, but feral descendants of domestic horses that tend to not grow beyond a certain size. Local lore has it that a group of horses survived the wreck of a Spanish galleon, but most likely they were just brought to the island by colonists in the 17th century. Assateague can be a harsh home, with a limited food supply and frequent storms, but the 300 or so horses that live there have proven themselves to be pretty tough

11. Runde Island, Norway // Puffins


The rocky cliffs overlooking the Norwegian Sea are home to around 700,000 seabirds, the most famous of which are the puffins. Puffins are adorable and—a rarity on this list—a non-invasive species. The island only has about 100 inhabitants, but is quite popular, as you might imagine, among birdwatchers. If you visit, stay the night in the lighthouse keeper’s house, which has been turned into a self-service cabin.

12. Seal Island, South Africa // Seals


Five acres of rock, 60,000 seals. In fact, there’s pretty much nothing on this island but seals (and seabirds). They roll around on the island all day, being cute, playing, and barking at each other with their little puppy faces. Everyone loves seals. But you know who else loves seals? Great white sharks. Tourists frequent the waters surrounding the island, the “ring of death,” to watch the abundance of great whites, some of which will pop up in order to snatch a seal. The sharks are known for propelling themselves toward the surface and then launching out of the water, seal in jaw

13. Zao Fox Village, Japan // Foxes


While not exactly an overrun island, this place is too whimsical not to mention. In the mountains of the Miyagi Prefecture on the main Japanese island of Honshu, a sanctuary holds more than 100 roaming foxes of six different types. Although they are wild, visitors can walk among them, and they don’t seem particularly shy.

14. Cayo Santiago, Puerto Rico // Monkeys

bdnf, Flickr // CC BY 2.0

About 400 Rhesus monkeys were imported from India to this small research island in 1938, and the population has more than doubled to about 1000 since. No humans inhabit the island, although it remains a research center for multiple universities. You can only see Monkey Island (yes, some people call it Monkey Island) from a kayak off the shore, however, as Rhesus monkeys are carriers of Herpes B. Not so cute.

15. Christmas Island, Australia // Crabs


These bright red crabs can actually be a little eerie given their massive numbers. There are about 45 million of them on this teeny island, and they're actually a conservation success story. Once a year, millions of adult crabs march from inland forests to the shore so they can reproduce. It’s the beginning of an elaborate mating and spawning process that is triggered by the phases of the moon, and eventually results in the ground turning glittery red with baby crabs, each just a few millimeters across, marching back inland from the ocean. 

The crab populations had been on the decline since the 1980s, when invasive yellow crazy ants (that's their actual name) began to swarm the island, and the baby crabs. But efforts to control the ant populations, and to protect the crabs from humans during migration with crab fencing and crab crossings, have helped the animals rebound. The 2015 migration was one of the best in 25 years. Good job crabs. 

25 Icy-Cool Facts About Polar Bears

From starring in Coca-Cola ads to becoming the poster child for climate change, the polar bear is quite the high-profile species. Ursus maritimus is a fascinating animal that roams across the Arctic Circle through Norway, Russia, Canada, Greenland, and Alaska, and there's more to them than the adorable faces you see in children's books and advertisements. Here are 25 facts you should know about the polar bear:


A polar bear walks across the snow at sunset.

Polar bears can weigh more than 1300 pounds and span more than 8 feet, 6 inches from nose to tail, making them the largest carnivores to currently walk the Earth. (Though other bears can grow larger, like Alaska's 10-foot-long Kodiak bear, they're omnivorous, while polar bears prefer an all-meat diet.) The males far outweigh their female counterparts, who may only weigh between 330 and 650 pounds. In general, though, a bear's weight fluctuates significantly throughout the year, with some bears packing on 50 percent more body weight over the course of a successful hunting season, then losing it over the course of their long fasting months.


A shot from below of two polar bears swimming in clear blue water

Because they spend so much of their lives on ice, rather than land, polar bears are the only bears to be considered marine mammals. They hunt, court, and mate out on the ice, spending many months of the year far from land.


A large polar bear opens its mouth in a roar.

Human beings aren't as high on the global food chain as you might think. Polar bears don't have any natural predators, and their intensely carnivorous diet puts them at the top of the food chain with species like killer whales, according to researchers, while humans fall somewhere closer to the middle. Don't worry too much about getting eaten by one, though—a 2017 study found that during the past 144 years, there have only been 20 fatal polar bear attacks in all of the five countries that have polar bear populations. However, as food becomes more scarce for the bears, humans living in polar territory may soon face more risk from starving bears.


A polar bear walks across a large field of ice.

Other than the two to three years a cub spends with its mother, polar bears are pretty much solitary creatures. Adults spend only a few days a year mating, then go on their own way, spreading out to hunt on their own. They rely on the scent left by the sweat glands on their paws to track other bears, using the smell to sense where potential mates might be headed, among other things.


A polar bear sleeps cuddled next to her cub.
Paul J. Richards, AFP/Getty Images

Polar bears can play nice with each other sometimes. On occasion, they will hang out together in large groups, especially if there's a big meal that multiple bears can take part in, like a whale carcass. When they do spend time together (in what's called a sleuth), male bears will play-fight with each other, wrestling and swatting at each other without doing any real harm. According to the documentary Polar Bears: Spy on the Ice, polar bears can recognize friends they've met before even if they go without seeing each other for many years.


A polar bear shares food with a cub.

When food is plentiful, polar bears are very selective about what they eat. They hunt seals, but if there are plenty available to hunt, they won't eat their whole catch. Instead, they'll only eat the energy-rich blubber (up to 100 pounds at a time), leaving the rest of the carcass for other animals to scavenge. When hunting is good, their diet is made up of about 90 to 95 percent fat. When times are lean, though, they'll happily branch out, eating reindeer, rodents, eggs, seaweed, and anything else they can get their claws on. However, because their bodies are so much better at digesting fat than protein, researchers think that if Arctic ice continues to melt and polar bears become unable access the ice (with its blubber-rich seals), they won't be able to get enough calories on land to survive [PDF].


A polar bear sprawls out on its stomach.

When they're not out on the ice scoping out seals, polar bears spend an incredible amount of time fasting. The female polar bears fast longer than any other mammal species—in Canada's Hudson Bay, pregnant polar bears can fast up to 240 days, or almost eight months. There's reason to think they'll be fasting even longer in the future as sea ice melts, leaving bears with fewer hunting opportunities and less time to accumulate the fat stores needed to get through the lean months. During the 1980s, non-pregnant polar bears spent 120 days fasting between hunting seasons, but researchers now think that the bears will have to go without food longer and longer, fasting for as much as 180 days at a time in the future.


Two polar bears walk through the snow.

The average bear might travel across 100,000 square miles in its lifetime, and that number may be getting higher. In 2013, a bear searcher told the BBC that polar bears were spending 9 to 13 percent more time being active to make up for the fact that the ice they hunt on is drifting faster, leaving them walking on a "treadmill" just to stay within their territory. One bear tracked by the WWF traveled almost 2300 miles from Norway to Russia in less than a year. Due to receding ice, polar bears have to walk farther to find prey, wasting valuable energy. The energy they gain from eating a single ringed seal might not even make up for what they expend trying to find and catch it.


A polar bear swims toward the camera.

Polar bears are savvy swimmers, paddling at an average speed of 6 miles per hour. And it's a good thing: Due to all that melting ice, polar bears are putting their swimming skills to lengthy use. In 2011, a study reported that a tagged female polar bear swam a total of 426 miles in one nine-day stretch across the Beaufort Sea above Alaska, losing 22 percent of her body weight in the process. Another bear in the study swam for 12 days, though she at least stopped to take some breaks.


A wet polar bear sticks its tongue out.

You'd think with all that plunging in Arctic waters, polar bears might get chilly occasionally. But since they're built to withstand extreme cold on a regular basis, they actually have the opposite problem: They overheat very easily, and are more likely to die from the heat than the cold. Their two layers of fur and solid layer of body fat (up to 4.5 inches thick) keep their metabolic rate consistent when temperatures reach as low as -34° F. They can sprint up to 30 miles per hour if need be, but much like you wouldn't want to run a race in a heavy ski jacket, polar bears can't spend much time chasing after their prey lest they overheat—a bear's body temperature can rise to feverish temps if they move too fast. On land, they typically only walk at speeds of three miles an hour, and their main hunting technique involves staying very still for hours or days at a time, waiting for a seal to emerge from the ice to breathe.


A polar bear sits with her two cubs.

In addition to changing their travel patterns and dinner prospects, climate change is altering polar bears' love lives. As the ice-traversing bears are forced to spend more time on the tundra, their habitats are starting to overlap with those of grizzly bears. In some places, the two species are getting more comfortable with each other, with amorous results. In Alaska and western Canada, grizzlies and polar bears are doing more cross-breeding, creating hybrid offspring.


A polar bear cub sits on its mother's back.

At birth, polar bears weigh anywhere from 16 to 24 ounces—about what a guinea pig does. As newborns, they're blind, toothless, and only about a foot long. But by the time they emerge from their den for the first time around four months later, they are substantially larger, weighing between 22 and 33 pounds. In addition to nursing, they'll begin eating solid food around that time, and by 8 months old, they'll weigh 100 pounds or more.


A polar bear swipes its paws in the water.

In order to balance on ice, polar bears boast giant feet. Their paws can measure up to 12 inches in diameter, acting like snowshoes to spread out their weight on thin ice and deep snow. The bumpy papillae (like the ones on your tongue) on their footpads help grip the ice, keeping them from sliding around. They also have long, curved claws that can measure almost 4 inches—all the better to grab onto slippery seals.


A polar bear leaps into the water.

While black bears, grizzlies, and other bear species spend each winter denning, forgoing eating, drinking, moving, pooping, and peeing for months on end, polar bears stay active all winter. Polar bears don't need to sleep through the winter, though, because there's plenty of food available to them in the coldest months, when they take to the sea ice to hunt for seals. The only exception is during pregnancy, when a female polar bear digs herself a den and remains sealed inside, surviving off her stores of fat, until her cubs grow large enough to survive outdoors.


Two polar bears sleep covered in snow.

Polar bears may not hibernate, but they are happy to lay low when bad weather hits. During the winter, they dig themselves into shallow pits in the snow to protect themselves from wind, sometimes remaining there for days as the snow piles up on top of them like a warm blanket. Sometimes, they take a similar approach to staying cool, digging through the tundra down to the permafrost during the summer to keep from overheating.


A polar bear wears a tracking collar.
Paul J. Richards, AFP/Getty Images

Considering how far they travel—both walking and swimming—over a given year, you can imagine how hard it is for scientists to track polar bears. By nature, they spend a huge amount of time alone in remote locations. Scientists use boats, helicopters, and low-flying planes to observe them, but that only works in good weather and in certain locations. So recently, they've turned to satellites, fitting bears with non-invasive radio collars and tracking them through high-resolution satellite imagery. It's cheaper than sending out a helicopter, and it lets researchers identify bears even in the most remote areas of the Arctic.


A swimming polar bear peeks its nose out of the water.

Polar bears don't have to worry about getting water up their nose. When they swim, their nostrils close to prevent them from breathing in water. They can swim at depths up to 15 feet, and while they typically only dive for a few seconds, they can hold their breath for more than two minutes, enabling them to sneak up on seals resting on ice floes. In 2015, scientists reported observing a record-breaking polar bear dive that totaled 3 minutes and 10 seconds. The hungry bear stalked three seals from afar, swimming almost 150 feet underwater without surfacing for a breath or to reorient himself to the seals' location before bursting out of the water where one of the seals was resting. (Sadly, his prey got away.)


A polar bear in a zoo swims with a ball.
Ina Fassbender, AFP/Getty Images

Though polar bears are sometimes known as the white bear, they aren't white. Their hair is colorless and hollow, and only appears white because of the way light scatters through their fur. (Under that mass of hair, their skin is as black as their noses.) When bears are subject to warmer temperatures in captivity, though, they can take on a bit of a verdant hue. Algae infestations can turn polar bears green, and not just on the outer layer of their fur. The colorful algae grows inside the hollow tube of each hair. This green growth thrives in humid climates, like Singapore, where the bears don't naturally live.


A Bulgarian stamp set featuring a polar bear, a seal, penguins, and a walrus.
State Agency for Information Technology and Communications of Bulgaria, Wikimedia Commons // CC BY 2.5

Though you might see polar bears and penguins together in Coca-Cola ads or on winter-themed pajamas, the two species never mix in real life. They live at opposite ends of the Earth, though they both spend their days in icy waters. Polar bears exclusively inhabit the Arctic, and penguins only live in the Southern Hemisphere. The closest they ever get is when they live in the same zoo.


Gold glitter on a black background

At the Assiniboine Park Zoo in Winnipeg, Canada, the polar bears have sparkly poop. In 2014, zookeepers began feeding each of their bears a different color of non-toxic glitter so that they could trace their bowel movements, analyzing the samples to identify health issues, track stress hormones, and generally see how the bears are dealing with zoo life. The colors help the zookeepers label which poop comes from which bear.


A 1938, black-and-white photo of a polar bear lying on its back in a zoo
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Captive polar bears have piqued public curiosity since as early as the Middle Ages, when the bears were occasionally given to European royalty by Viking traders. In the 1200s, when Henry III kept one in London, it was muzzled and chained but allowed to catch fish and swim in the Thames River. In the 17th century, Frederick I of Prussia kept a defanged and declawed polar bear, staging public fights between it and other large mammals for public amusement.


The orange cover of 'Teddybär' shows a person in a polar bear suit with his arms wrapped around a smiling boy.

In the early 20th century, getting a picture with a man dressed in a polar bear suit was a fairly standard activity in Germany, at least according to the many photos found by French photo collector Jeann-Marie Donat. Donat spent 20 years tracking down the vintage photos, taken between 1920 and 1960, for his 2016 book Teddybär. There are several potential explanations for why so many Germans elected to stop for photos with people in polar bear suits (or to dress up as polar bears themselves). Donat suggests that it might trace back to the popularity of the two polar bears that arrived at the Berlin Zoo in the 1920s, while Hyperallergic notes that the costume was created as a Fanta advertising stunt, designed to distract Germans from the horrors of World War II. The photos show people young and old posing next to bears at the beach, in parks, in the street, in the summer and winter, alone and in groups. They all look delighted to get a chance at a polar-bear souvenir.


Knut and his handler pose for photos lying down on their bellies.
John Macdougall, AFP/Getty Images

Knut, a polar bear cub born at the Berlin Zoological Garden in 2006, was hand-raised by zookeepers after being abandoned by his mother at birth. The cute cub became an instant tourist attraction—the most famous bear in the world, even—and the zoo's attendance rates skyrocketed, netting an extra $1.35 million in tickets when the bear began making twice-a-day public appearances.

But not everyone was psyched about "Knutmania." The young bear's popularity proved to be controversial for animal rights organizations like PETA, whose German spokesperson Frank Albrecht said the zoo should have let the orphaned Knut die rather than continue hand-feeding him, a process that he called a "gross violation of animal protection laws." In 2007, the bear received an anonymous, handwritten death threat from a hater who simply wrote "Knut is dead! Thursday midday." The zoo took the fax seriously enough to assign triple the amount of zookeepers keeping watch over the polar bear during his daily public romp. (Knut continued to live at the Berlin zoo until his death at age 4 from an autoimmune disease.)


Photographers crowd in front of a barrier to photograph Knut at a zoo.
John Macdougall, AFP/Getty Images

In 2007, celebrity photographer Annie Leibovitz photographed Knut for the cover of Vanity Fair's annual "Green" issue. While Knut appeared solo on the cover of the German edition, he was Photoshopped into an image with Leonardo DiCaprio for the American edition. After his death, the Berlin zoo erected a bronze statue in his honor, and his body was preserved for display at the city’s natural history museum.


A green sign in a snowy field reads 'Polar Bear Alert: Stop.'
Paul J. Richards, AFP/Getty Images

Churchill, a town in Manitoba, Canada on the shores of the Hudson Bay, is known as the polar bear capital of the world. During the fall, hundreds of polar bears pass through on their way to their icy hunting grounds on the bay, waiting nearby as the ice hardens for the winter. The locals have adopted unique ways of living with the hungry bears. Many don't lock their doors, so that if someone is running away from a polar bear, they can duck into any doorway. Since Halloween falls right in the middle of polar bear season in town, city employees, police officers, volunteer fire officials, and polar bear conservationists stay on patrol to drive away any bears that might be tempted to go trick-or-treating themselves, using helicopters, sirens, air horns, rubber bullets, and more to keep the bears at bay. Kids, for their part, aren't allowed to wear anything white for the evening.

Churchill also runs a "polar bear jail" for bears that continue to wander into town. Residents are encouraged to call the Polar Bear Alert Program hotline year-round if they see a bear in town, and conservation officers will come and try to scare it away. If shooting loud scare rounds at the bear doesn't do the trick, they trap the bear, or, if all else fails, hit it with a tranquilizer dart and take it to the Polar Bear Holding Facility. The specially-designed compound can hold up to 30 bears and is meant to keep bears that are aggressive or persistently return to the community. When the bay freezes, these bears are transported by helicopter or vehicle onto the ice, where they resume their normal winter hunting routine. With warmer temperatures keeping bears off the ice for longer and longer periods, more towns may soon have to learn from Churchill's strategies for peaceful coexistence.

Where Do Birds Get Their Songs?

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]


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