Baby It's Cold Outside! How the Arctic Fox Survives Frigid Temps

Also known as the white or polar fox, the arctic fox (Vulpes lagopus) is an exceptionally cute yet immensely tough member of the Canidae family of dog-like carnivorans — which means it's related to other foxes, wolves and dogs. Prevalent throughout the Arctic regions of the Northern Hemisphere, usually on tundra or mountains near the sea (two of the coldest places on the planet), they range in size from about as big as a small Chihuahua to as large as a Jack Russell terrier, and are said to be second only to polar bears as the most popular animals that travelers want to see and photograph when visiting the Arctic.

Among the arctic fox's most outstanding characteristics? Being able to survive in temperatures as low as -58 degrees F (-50 degrees C) largely due to their small stature. Their compact body, short muzzle and legs, and small rounded ears minimize the amount of surface area that is exposed to the cold air. Additional reasons they can thrive in a frozen habitat include a thick, layered fur coat (the warmest pelt of any animal living in the Arctic) that traps a layer of air and preserves body heat, and fluffy tails that cover their heads like a built-in blanket for added insulation when they curl up to sleep.

They are the only canid that grows fur over their foot pads, which helps them walk easily on snow. An added bonus: They have something called "counter-current blood circulation," which reduces blood flow to their feet to ensure they don't get frostbitten. When conditions become too cold, their metabolism increases to provide warmth, with their winter basal metabolic rate around 25 percent slower than it is during the summer. Not only does this cool trick allow them to withstand frigid temperatures, but it also enables them to survive longer without food — a key tool when food is scarce in the dead of winter.

They come in just two colors: white or blue. In the winter, white foxes are almost entirely white (which comes in handy when camouflaging in the ice and snow), and blue foxes are pale-bluish gray. Their fur changes to brown or gray during the summer to help them blend in with their surroundings.

"This color change helps camouflage them for hunting," says Brint Spencer, director of Brandywine Zoo in Wilmington, Delaware, in an email interview. "The white fox is more common, and one theory is that the blue phase tends to be more coastal where the ocean waters do not freeze."

So, What Other Animals Can Survive in That Kind of Cold?

Like the arctic fox, many other animals have developed multiple defenses that enable them to adapt to extremely cold conditions. "They typically have a higher metabolism, reduced body surface area and thick fur or a layer of fat (blubber) to insulate themselves," says Spencer. "Often, they will feed heavily in the fall to have enough stored body fat to get through the winter."

Among these animals is the snow leopard (found in the Alpine and semi-Alpine regions of Central Asia); arctic hare (residing mostly in the northern regions of the Arctic Circle, predominantly in Northern America, Europe, Greenland and the North Pole); leopard seal (found commonly in the Antarctic); and musk oxen (located in Arctic Canada and Greenland).

Yet others include the walrus (commonly found around the North Pole in the Arctic seas); a medium-sized whale known as the narwhal (residing in the Arctic); caribou (which live in Arctic, Subarctic, mountainous, as well as the tundra regions of North America, Europe, Asia and Greenland); and beluga whale (found in the Arctic and Subarctic seas).

Probably the most popular cold-weather creature is the polar bear, which is fully equipped for Arctic life with his thick coat of long, heavy white fur that helps him to blend into the surroundings and keeps him warm by trapping a layer of insulating air. In addition, the polar bear's oily fur keeps moisture at bay and protects him from frigid waters, while a layer of blubber directly below the skin provides insulation from the biting cold. Polar bears have large paws with furry soles to help them walk easily on snow and ice, though these massive creatures prefer to spend most of their lives in the sea.

Getting Back to Arctic Foxes ... Are They Dangerous?

Arctic foxes usually aren't dangerous or aggressive to humans. In fact, they would prefer to flee from a human rather than fight. Foxes have sometimes been known to attack livestock, such as poultry or rabbits, but seeing as the arctic fox is really only found in the Arctic tundra, it doesn't often have the chance to interact with humans and livestock.

"Almost all mammals can potentially carry rabies, and arctic fox are the primary hosts for a strain of rabies named for them," adds Spencer. "There have been human fatalities from Arctic rabies."

What Do They Eat?

The arctic fox will eat just about anything he can get his paws on. Generally preferring to eat meat, they've also been known to enjoy the occasional seaweed and berries, so they can be considered omnivores. Some of the typical prey includes many rodents, such as voles and lemmings, as well as birds and eggs.

The fact that their coats change color year-round means they are always camouflaged and able to sneak up on prey. With their wide (but short) ears, an arctic fox can hear its prey moving under the snow. Once it has located its next meal, the fox will pounce straight up then down right on top of its victim. In the fall, the arctic fox will work hard to store up body fat, increasing its weight by up to 50 percent. During winter, when food becomes much scarcer, the arctic fox often will follow polar bears around and then scavenge what it can off a kill once the bear has had its fill.

Where and How Long Do Arctic Foxes Live?

"They are circumpolar, and found in Alaska, Canada, Greenland, Iceland, Northern Europe and Russia," says Spencer. Their habitat includes dens, which might be in a mound on the open tundra, under a pile of rocks or in the side of a cliff. A fox den has many tunnels with several entrances.

An adult male is called a dog and an adult female is called a vixen. Babies are called kits, and a group of babies born at the same time is called a litter. Older brothers and sisters sometimes help raise the youngest kits. The arctic fox usually breeds once a year, producing a litter of up to 20 dark-furred pups that are born between April and June; gestation is about 52 days.

Pups are weaned about 45 days after birth, and then leave the den to live on their own beginning in September or October of the same year. Young become sexually mature at 9 to 10 months of age.

"Similar to small domestic dogs, they will live 10 to 12 years in human care," says Spencer. "Life span in the wild tends to be much shorter. The record longevity is a little over 16 years."

Can You Have an Arctic Fox as a Pet?

Although it might be tempting to rush out and get a cute little pet fox as soon as possible, it's important to think about all of the various factors that go into owning this exotic animal.

While you can legally own an arctic fox if you live in the Arctic tundra habitats of Northern Europe, Northern Asia and North America, perhaps the biggest problem of having one is its smell. They have odorous urine similar to the spray that a skunk would emit, and they also secrete odor from glands beneath the fur.

Stubborn and temperamental, they are difficult to train and extremely disobedient as well. But you can train them; you just need to put more effort and time into the process than you would for dogs. If they don't get enough exercise, they also can get bored easily and start chewing furniture and other things. Finally, they need plenty of attention compared with other pet foxes, which means plenty of human interaction.

"There are many local ordinances prohibiting private ownership of wild animals," says Spencer. "You should check with your local government before obtaining any exotic pet."