Information on the Polar Bear, a fascinating species that lives in arctic regions and differs from other bears in many ways.
The Polar Bear, or Ursus maritimus (sea bear) can be found in the arctic regions of North America and Siberia. The Polar Bear is considered a potentially threatened species. That means it would be very easy for the species to become endangered. There are currently between 22,000 and 27,000 Polar Bears in the world.
Polar Bears are among the largest of bears species. Male Polar bears grow to between 8 and 10 feet high and weigh anywhere from 550 to 1700 pounds. Females are a little smaller; they grow to between 6 and 8 feet and weigh 200 to 700 pounds.
Polar Bears are perfectly adapted to survive in the harsh conditions of the Arctic, where winter temperatures can often plunge to -45°C (-50°F). Adaptations to its cold, wintry habitat include its fur color, which blends with the snowy environment providing camouflage, and its large size, which helps maintain body temperature. For warmth, they have two layers of fur that provide them with good insulation, so that they experience almost no heat loss. The polar bear has a layer of blubber beneath its skin that can be as much as 4 1/2 inches thick. Small ears and tails are more characteristics that help to prevent heat loss.
The furred feet of the Polar bear help to insulate it against cold and provide for traction on the slick, iced surfaces on which it must walk. In addition, the Polar Bear has small bumps called papillae on their feet that further keep them from slipping on ice.
The Polar Bear has an acute sense of smell, and this helps it locate its prey even when it is hidden or camouflaged in drifts of snow or ice. The Polar Bear is also an excellent swimmer, and swims at about 7 mph. Oddly the polar bear paddles only its front feet while swimming or treading water, and stretches out its long neck to increase its area of vision, just as it does while on land.
Because the hairs of its waterproof coat are hollow, they are especially insulating and help the Polar Bear stay afloat. The Polar Bear can remain underwater a long time, and has been clocked underwater for more than 2 minutes. It often surprises young seals and walruses by swimming under the water and out to the ice floes that they are resting on.
The Polar Bear eats more meat than any of the North American bears, and has much larger canine teeth and molars that are sharper than other bears. The differences in their diet and in their teeth may very well be due to the deficiency of plant growth in its environment.
While seals are the Polar Bear staple food, it is not finicky. It may feed on fish, birds, and bird eggs, and it will eat a variety of other foods if available. Polar Bears have been observed eating small mammals, dead animals, shellfish, crabs, mushrooms, berries, grasses and algae.
The Polar Bear hollows out a winter den in a protected snowbank. Unlike Black and Grizzly bears, the Polar Bear does not actually hibernate; it is merely lethargic during the time that they spend in the den. Females den from approximately November to March each year, during which time they do not eat, drink, or defecate. They give birth during this period. Males den for much shorter periods, usually from late November to late January, but may be out and about at any time of the year.
Another difference that Polar Bears display is that, while Black Bears and Grizzlies are primarily nocturnal, Polar Bears are unpredictable in the time that they hunt. They may be active at any time of the day or night.
Hudson Bay and James Bay, one of the worlds largest denning areas for Polar Bears, is the only known place where Polar Bears den in the ground rather than snow. They dig caves in the lake and stream banks by digging down to the permafrost. This area is exceptionally far sorth for the Polar Bears, and scientists believe that they use these permafrost dens in the summer to cool off. No large denning areas have ever been found in Alaska; scientists speculate that Polar Bears in that region may winter in Siberia and then float across to Alaska on ice floes in the spring.
The Polar Bear only mates in April through May every two years. Sometimes Polar Bears do not mate until every third year. Female Polar Bears only have an average of five litters in their lifetime and this combined with the fact that humans are inexorably encroaching upon their habitat, has contributed to their declining numbers.
The female Polar Bear has a litter in its winter den of 1 to 4 (usually 2) young born anytime from November through January. When the cubs are born, they are about 12 inches long and weigh about one pound. They are blind and toothless and covered with soft, white fur. They grow rapidly on the milk they get from their mother, which contains about 30% fat. Cubs will remain with their mother anywhere from one and a half to two and half years, continuing to live in the den with her.
Polar Bears are very aggressive. There have been several cases of Polar Bears attacking humans. Due to the fact that there has been very little contact between Polar Bears and humans, they have not yet learned to fear man.
The threat of extinction for Polar Bears may not be as imminent as it is for other species, but it is still a very real possibility. Their slow breeding habits make them vulnerable, and global warming from pollution could have a disastrous effect on the cold-loving Polar Bear. If efforts are not made to protect Polar Bears and their steadily shrinking environment, their numbers may decrease even more in years to come.