Also, with our climate changing rapidly and the Arctic icecap melting, how many polar bears are left in the world? Discover this and other fascinating tidbits about this impressive species.
What is a Polar Bear?
Polar bears, scientifically known as Ursus maritimus, are the largest bear species in the world. Not only that, but they are the largest land carnivores on earth. They are known for their massive size, their ability to weather extreme cold, and their striking white fur. But did you know that polar bears are not actually white? Their skin is black, but two layers of fur hide it. The undercoat is dense, while the outer coat is translucent, reflecting the color of its surroundings. Since polar bears live among ice and snow, they appear white. Besides acting as efficient camouflage, this outer hair also helps to trap heat from the sun for warmth. Polar bears are physically huge with bulky shoulders, a thick layer of fat for insulation, and blocky paws to help them swim. To put it in perspective, they are even larger than the fearsome Kodiak bear! Female polar bears can grow up to 6-8 feet in length and weigh 300-700 pounds. Male bears are much larger, sometimes twice or even three times as big as the females. Male polar bears have a maximum length of 8-10 feet, while their weight usually falls between 800-1300 pounds. The largest known polar bear stood at 11 feet on its hind legs and weighed a whopping 2,209 pounds!
How Many Polar Bears Are Left in the World?
Estimates show that there are between 22,000 and 31,000 polar bears left in the world. This does not include the 300 or so polar bears in captivity. Although these numbers are not serious enough to warrant the Endangered status, they are still not high enough for comfort.
Are Polar Bears Endangered?
The World Wildlife Fund (WWF) lists polar bears as Vulnerable. This means that, although they aren’t rare enough to be endangered, extinction is still a threat. Conservationists often consider the polar bear to be the “poster child for climate change” as their status has been a matter of serious concern for decades. A number of factors negatively impact polar bear populations:
Climate Change
As our climate changes for the warmer, Arctic ice is melting. Polar bears rely on ice for nearly every aspect of their lives, including hunting, resting, travel, mating, and even denning. As the ice melts, the water levels rise. This reduces habitat size and forces polar bears further inland, where they may come into conflict with people. It also increases the difficulty of catching prey. Polar bears use ice as a platform for hunting seals, their favorite meal. Seals use air-holes in the ice when they surface for air, giving bears a chance to attack them. Seals also use the ice to bask, leaving themselves vulnerable.
Pollution
Pollution is a serious threat to polar bears. The Arctic may seem clean and fresh, but in reality, it is full of pollutants. These chemicals, metals, and plastics are brought to the Arctic by air and ocean currents, where they are ingested by organisms at the bottom of the food chain. As other animals eat these organisms, the pollutants are carried up the food chain. By the time polar bears ingest them, the pollutants are highly concentrated and able to cause significant damage.
Hunting
With their ferocious reputation and luxuriant fur, polar bears make a tempting target for trophy and sport hunters. The United States has outlawed polar bear hunting except for Alaskan Natives. No limit has been imposed on them, provided they are not wasteful. However, this type of hunting is still legal in some parts of Canada. Policy disagreements between the U.S. and Canada have stranded dozens of dead polar bears in Canada after the American hunters have gone home.
Where Are Polar Bears Found?
Polar bears mostly live north of the Arctic Circle, though some populations live southward in Canada’s Hudson Bay. Polar bears reside in the United States (Alaska), Canada, Russia, Greenland, and certain Norwegian islands. They live mostly on the ice, though as climate change causes widespread melting, humans may encounter them inland. Also called sea bears, polar bears are excellent swimmers, moving as fast as 6 mph in the water. Do polar bears live in Antarctica? No, they don’t! Though Arctic and Antarctic environments are similar, from the bitter cold to the availability of ice and seals, bears of all kinds only exist in the Northern Hemisphere. This is due to where they happened to evolve and not necessarily environmental factors. The Arctic and Antarctica have never been connected, so polar bears never had the chance to migrate. Ecologists speculate that polar bears would fare well in Antarctica. A little too well, perhaps. The local populations of seals, birds, and penguins are not accustomed to large land predators and would probably not be wary enough. This would likely lead to overfeeding and the collapse of the ecosystem.
Polar Bear Diet and Predators
Polar bears are apex predators, relying on the meat and fat of their kills to survive. Their favored prey are seals, particularly ringed and bearded seals. These animals have an extremely high fat content; this is necessary for polar bears to maintain their own fat stores. They eat mostly the skins and blubber, often leaving the meat for other carnivores. Other sources of food include narwhals, beluga whales, walruses, muskox, reindeer, fish, eggs, and rodents. Berries and garbage may supplement their diet. Now for the real question: do polar bears hunt humans? The answer is yes; sometimes, they do. This has become more of a problem as their habitat shrinks, and they are driven more inland. Polar bears prefer nonhuman prey, but they will eat whatever they can get if their regular food supply is scarce. Attacks by these predators are often fatal due to their enormous strength. Here’s an example of a dog that drove off a polar bear that got too close to its owner!
Polar Bear Reproduction and Lifespan
Polar bears usually breed from April to May. The cubs gestate for up to 9 months, after which the female gives birth to a litter of 1-4 cubs. After digging out a den, she takes them into hibernation until the spring. Cubs are usually weaned at 2-3 years, after which they leave their mother and strike out on their own. Polar bears are solitary animals, with the exception of a female with cubs. In the wild, polar bears can live as long as 25-30 years. That number can increase to more than 30 years in captivity. Polar bears are powerful predators at the very top of the food chain. Whether found in the wild or in captivity, they are a magnificent sight.
