Polar Bears

The polar bear is a large, magnificent animal and is the true symbol of the northern Arctic region. Extremely well-adapted to life on the drifting sea ice of the Arctic Ocean, the polar bear is a circumpolar animal, as his range coincides roughly with the Arctic Circle. This animal is found in five countries: Canada, Alaska (U.S.), Russia, the Svalbard (of Spitsbergen which is part of Norway) and Greenland (Denmark). The movements of the polar bear are largely governed by the drifting of the ice. Polar bears are carried south by the ice in the spring and return northward when the ice breaks up.

The polar bear is one of the largest land carnivores in the world. Males average 6.5 to 8 feet in length and weigh 650 to 1,700 pounds. Females are somewhat smaller. The polar bear's body is covered with a dense coat of white fur, which helps the polar bear survive in a climate where the temperatures can plunge to -60 degrees F. Scientists have recently discovered that the hairs on the bear's coat are hollow and can channel ultraviolet light from the sun down to the bear's black skin, which absorbs it. This means that the bear's body is like a greenhouse, trapping solar energy and then storing it in the form of heat. The polar bear is also protected from the cold by a thick layer of fat under its skin.

Although polar bears are basically land animals, they are powerful swimmers. Their bodies are well-adapted to this semi-aquatic life. Their thick fur coat is water-repellent as well as being insulated to keep out the cold. The bear's huge feet are partly webbed, making them more effective paddles when the animal is swimming.

The polar bear's principal diet is seal, particularly the small ringed seal that is plentiful in the waters of the Arctic. Polar bears wander a great deal in the course of their hunting. Seals are most plentiful in the areas where the solid ice joined to the land meets with the drifting ice. Here, ocean currents also create long, narrow channels of open leads which are much favored by seals and, therefore, by the polar bears that come to hunt them. During the summer months, when many bears become "stranded" on the land as the ice recedes northward, they turn to a variety of quite different foods in the absence of seals. They also eat small mammals, birds and their eggs, and plants. For these few months, polar bears switch to an omnivorous diet, similar to their relatives, the brown bears.

Like most predators, polar bears have good eyesight, in spite of the fact that for several months of the year they live in a world of total darkness. Their hearing is excellent, and their sense of smell is phenomenal. A bear uses its nose to catch scents carried on the wind from up to several miles away. This is how a bear finds and tracks down seals.

Springtime is the mating season for polar bears, with most activity occurring in April and May. In October or November, the bears dig dens in the snow or tundra and use them for giving birth. The cubs are born in December or January and weigh only 16-32 ounces and are about the size of an adult guinea pig. Typically, two are born and they are hairless, blind, and deaf at birth. They first emerge from the dens in March or April. Young polar bears stay with their mother until they are over two years old, traveling with her in summer and sharing her den in winter. At this point, the young are almost fully grown and the mother will leave the cubs in order to mate again and start another family. At the age of five or six, polar bears are fully grown and can reproduce. Female bears can continue to breed until they are 20 years old.

  • Subjects:
    Arctic Animals, Bears, Habitats and Ecosystems, Animal Hibernation and Migration, Animal Structure and Movement, Animal Survival and Adaptation, Mammals