Polar Bear adaptation to the frigid and unforgiving Polar climate is one of nature's marvels. The dynamic sea ice, where polar bear live, is one of the cruelest and grimmest climates on planet earth.
It's only in the latest evolutionary cycle that bears adjusted to arctic sea life. It started about the time of 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 became a copious year-round food source near a population of brown bears, who then began to inhabit the ice, changing into something similar to the polar bear of today, approximately 100,000 years ago.
Weighing roughly 330 to 1,760 pounds, the length of the polar bear's body is around 6.6 to 10 feet. The male body is usually heavier than the female. The polar bear, akin to the brown bear, is large and thickset. It has an long neck and small head. Its fur, usually white, may seem yellow, due to oxidation.
A polar bear has black skin, which helps it adjust to the Arctic temperature, absorbing and holding heat from the sunlight. It is definitely well dressed 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) offers warmth and traction. Because each foot is so huge, it acts as a handy snowshoe.
It adjusts well to swimming with its broad front paws that serve as paddles and when swimming underwater it lays the tiny ears flat for protection, and its nostrils close under water. It paddles at about 6 and one-half miles per hour --forepaws only, hind feet trailing--and can remain under water for about 2 minutes. The hairs of its waterproof coat are hollow which is an adept insulator and increases the bear's buoyancy when swimming.
A polar bear has an excellent 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 various objects with surprising dexterity.
With canine teeth bigger and malariform teeth sharper than those of other bears, the polar bear is the most carnivorous North American bear.
A polar bear lives on Arctic islands, sea ice, and water and continental coastlines. It chooses 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 isolated. Most pregnant females spend the autumn and winter on land in maternity dens.
A polar bear travels throughout the year within single home ranges, which tend to be a larger area 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 discovered near Canadian Arctic Islands, while larger home ranges can be found in the Bering or Chukchi Sea areas. The polar bear remains in the same area during the same time of year. A polar bear is capable of traveling 19 miles or more per day for several days, although some are capable of a good deal more than that. One can only hope that polar bear adaptation will carry on, as their habitat area shrinks and the pressures of civilization continue to encroach on the the natural homes where the polar bear dwell.
For more information, check out my blog Polar Bear News. You can also find information at Are You Polar Bear Aware? and Polar Bear Video Showcase
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