Information About Polar Bears

Polar bears are the largest land carnivores on Earth and are believed to have evolved as far back as 200,000 ago years from the brown bear species. An inhabitant of the far north regions, polar bears are equipped to handle the rigors of living in extreme cold. Polar bears are hunters that depend on their skills to eat. In 2009, there are an estimated 20,000 to 25,000 living in the wild according to the World Conservation Union, meaning that the species is bordering on becoming endangered.

Characteristics

The average adult male polar bear weighs anywhere from 900 to 1,700 pounds and is seven to eight feet in length. The female polar bears achieve half this size. Polar bears have a long neck and narrow head with small, round ears. Polar bears possess a thick coat that covers all parts of the body except for the foot pads and the nose. The fur is water repellent and sits over a layer of body fat that insulates the animal from the cold. The skin of a polar bear is actually black, which allows it to absorb as much heat as possible from the sun. The fur ranges from creamy white to a yellowish shade when they are molting their coat. Polar bears have huge feet that make them great swimmers; they act almost like oars when the bear is in the water.

Habitat

There are as many as 19 sub-populations of polar bears in the countries of Canada, the United States, Russia, Norway and on the island of Greenland. In total, the polar bear can be found within a five million square mile area. Polar bears spend a great amount of time near the Arctic pack ice, and the ice provides the bear with a place from which to hunt. They have been known to create dens on this ice in which to have their young. When the southern portion of the Arctic ice cap melts and recedes in the summer months, some polar bears will follow the ice northwards in search of prey, while others choose to remain on land.

Polar Bear Diet

The diet of the typical polar bear consists mostly of seals. Ringed seals and bearded seals are hunted and killed by polar bears and then eaten, with the harp seal also falling victim to bears on occasion. Bears will smell out seals in their dens on the ice in the spring months and easily kill and consume them. On the sea ice, polar bears have been seen waiting hours for a seal to come up for air through a hole in the ice. When it does, it is killed by the bear. Young walruses, fish, beluga whales and the carcasses of dead whales and adult walruses provide the polar bear with meals as well.

Reproduction of Polar Bears

From March through June, the polar bears will breed. The males find the females by their scent and will stay with a female for only a short span of time before leaving in search of another potential mate. The pregnant females need great amounts of food during the summer and early fall months before giving birth, as she will need to live off this fat over the winter. The female will find a place to dig a den in the snow during the late autumn and finally give birth in December or January. There are usually two cubs in the litter and the little ones will stay with the mother until they are as old as two and a half years of age. After living off their mother's milk, the cubs will leave the den with the mother in March or early April.

Threatened Species

The effects of global warming are keenly felt by polar bears, as their habitat is slowly beginning to disappear. As the sea ice melts, the hunting grounds of the polar bear change, with the bear having to venture farther out to find suitable ice to hunt seals from. This in turn means that cubs and adults need to expend greater amounts of energy to find food, which increases polar bear mortality rates. The female bear has an average of only five litters in their lifetime, which is one of the lowest mammal reproductive rates. In May of 2008, the polar bear was listed by the U.S. as a threatened species by the Endangered Species Act.

Resources

• Defenders of Wildlife website
• World wildlife.org website