Polar Bears Adaptation to the Cold and Unforgiving Arctic Climate

Polar Bear adaptation to the wintery and bitter Northern climate is one of nature's marvels. The shifting sea ice, where polar bear live, is one of the unkindest and most relentless climates on planet earth.

It's only in modern evolutionary time that bears adjusted to arctic sea life. It commenced during the Ice Age, in the northern seas, when the seals needed to breathe and mate near the water's surface. By doing this, the seals placed a rich year-round food source near a population of brown bears, who then began to inhabit the ice, developing into something similar to the polar bear of today, around 100,000 years ago.

Weighing about 330 to 1,760 pounds, the length of the polar bear's body is approximately 6.6 to 10 feet. The male body is usually bigger than the female. The polar bear, akin to the brown bear, is heavy and heavyset. It has an drawn out neck and small head. Its fur, normally white, occasionally appears yellow, due to oxidation.

A polar bear has black skin, which assists it's adjustment to the Arctic temperature, absorbing and holding heat from the sunlight. It is unquestionably well attired for the weather with a layer of fat more than 4 inches thick, allowing for efficient insulation. The dense fur on its feet (its foot is about 9 inches wide and 12 inches long) allows for warmth and traction. Since each foot is so big, it acts as a practical snowshoe.

It adjusts well to swimming with its wide front paws that serve as paddles and when swimming underwater it lays the small ears flat for protection, and its nostrils close under water. It paddles at about 6 and one-half miles per hour --forepaws only, hind paws trailing--and can remain under water for about 2 minutes. The hairs of its waterproof coat are hollow which is an effective insulator and increases the bear's buoyancy while swimming.

A polar bear has a keen sense of smell, sensing prey at a distance of about 20 miles. Although little is known about its sense of touch (its eyesight and hearing is acute), a polar bear is able to manipulate varied objects with great dexterity.

With canine teeth larger and malariform teeth sharper than those of different bears, the polar bear is the most carnivorous North American bear.

A polar bear inhabits Arctic islands, sea ice, and water and continental coastlines. It favors the sea ice habitat, with water channels or cracks through the ice, next to continental coastlines or islands. Some polar bears spend part of the year on land, although in warmer climates a bear could become stranded. Most pregnant females spend the autumn and winter on land in maternity dens.

A polar bear journeys throughout the year within single home ranges, which are inclined to be larger than for other mammal species because of the alterations in sea ice from year to year and even season to season. Small home ranges (19,000 to 23,000 miles) can be found near Canadian Arctic Islands, while larger home ranges can be found in the Bering or Chukchi Sea areas. The polar bear remains in the general area during the same time of year. A polar bear walks 19 miles or more per day for several days, although some are capable of much more than that. One can only hope that polar bear adaptation will continue, as their habitat area shrinks and the pressures of civilization continue to encroach on the the natural homes where the polar bear calls home.