Polar Bears Adaptation To The Cold And Unforgiving Northern Climate
Polar Bear adaptation to the wintery and unforgiving Polar climate is one of nature's mysteries. The dynamic sea ice, where polar bear live, is one of the unkindest and most unforgiving climates in the world.
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 reproduce near the water's surface. By doing this, the seals put a plentiful year-round food source close to a population of brown bears, who then set out to dwell on the ice, developing 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 generally heavier than the female. The polar bear, akin to the brown bear, is large and heavyset. It has an drawn out neck and small head. Its fur, typically white, sometimes appears yellow, due to oxidation.
A polar bear has black skin, which helps it adjust to the Arctic temperature, soaking up and holding heat from the sunlight. It is decidedly well attired for the weather with a layer of fat more than 4 inches thick, providing good insulation. The thick 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 handy snowshoe.
It adapts 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 --paws only, hind paws trailing--and can stay submerged for about 2 minutes. The hairs of its waterproof coat are hollow which is an effective insulator and increases the bear's buoyancy when swimming.
A polar bear has a good 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 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 lives on Arctic islands, sea ice, and water and continental coastlines. It prefers the sea ice habitat, with water channels or cracks through the ice, next to continental coastlines or islands. Many polar bears spend part of the year on land, although in warmer climates a bear may become marooned. Most pregnant females spend the autumn and winter on land in maternity dens.
A polar bear travels throughout the year within individual home ranges, which tend to be larger than for other mammal species because of the shifts in sea ice from year to year and even season to season. Small home ranges (19,000 to 23,000 miles) can be observed near Canadian Arctic Islands, while larger home ranges can be seen in the Bering or Chukchi Sea areas. The polar bear remains in the general area during the same season. 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 becomes increasingly smaller and the pressures of civilization continue to encroach on the the natural homes where the polar bear live.
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