Body and Habits
The largest bears, the Kodiaks found in Alaska, may be 10 to 12 feet (3 to 3.7 m) long and weigh as much as 1,700 pounds (770 kg). Some small Asiatic bears weigh only about 100 pounds (45 kg) and are about the size of large dogs.
The bear has a massive head, short, erect ears and short, powerful limbs. Its teeth are used for both grinding and tearing. Bears have poor eyesight and hearing but a keen sense of smell. Each foot has five long, sharp, curved claws used for climbing, digging, and holding prey. The bear moves with a lumbering, flat-footed gait, but can run fast when necessary. Bears can run up to 35 miles (56 km) per hour for short distances. They frequently stand and walk on their hind legs, using their forepaws to reach high objects. Bears are skillful tree climbers and good swimmers.
Bears feed on fish, small mammals, fruit, roots, seeds, insects, carrion, and honey. When a bear finds a nest of wild bees, it tears the nest apart and devours the honey. The animal's thick fur protects it from bee stings; the only unprotected spot is the nose.
Bears usually live from 15 to 25 years in the wild and up to 45 years in captivity. Most species are dormant during the winter, sleeping in caves, dens dug in the earth, or other protected places. Cubs are born in the spring; one pair is a normal litter. Cubs are very small at birth, weighing from 8 to 16 ounces (230 to 450 grams). They stay with the mother for a year.
Although bears have similar shapes, they come in very different sizes. The largest bear of all is the Kodiak, an Alaskan brown bear. Next comes the polar bear. In fact, some polar bears have longer bodies than Kodiaks do—although they don’t weigh quite so much. Other big brown bears, such as the grizzly, rank third in terms of size.
Some kinds of bears are fairly close in size. Spectacled bears, American black bears, sloth bears, and Asiatic black bears are all about the same length. Spectacled bears weigh more than the other three species of bears, however. Sloth bears weigh less than the other three. The smallest of all the bears are the sun bears.Within each group of bears, some members are bigger than others. Males in a group are usually bigger than females.
The smallest bears are sun bears. A sun bear is only about 3 feet (0.9 meter) long and weighs 60 to 100 pounds (27 to 45 kilograms). That’s the size of a large dog.
Sun bears are different from other bears in many ways. Their fur is black and short, not shaggy like that of most bears. Sun bears have solid, sleek bodies. Their noses may be gray or orange. The sun bear also has a white or yellow marking on its chest. Long ago, people believed the marking looked like a rising sun—thus the name sun bear.
Sun bears mostly search for food at night. They rest during the day. To protect themselves from predators, sun bears climb trees. They build nestlike beds in the trees.