The diet of bears is varied and flexible: most kinds eat just about anything. Bears that live near campsites or dumps do not even mind swallowing inedible things along with their food. Most species are especially fond of ants and honey. Bears also eat seeds, roots, nuts, berries, insects, rodents, fishes, deer, pigs, and lambs. Some brown bears fish for salmon, and the polar bear feeds almost exclusively on seals. The spectacled bear, on the other hand, eats mostly fruit and plant shoots. The giant panda is also nearly always a vegetarian, eating almost solely bamboo.

Like humans, bears walk in plantigrade fashion, or on the soles of the feet with the heel touching the ground. Bears normally walk on all fours, but they can stand or walk upright for short periods. They move both legs on one side of the body forward at the same time. This gives them a deceptively clumsy looking gait. Bears are actually swift and agile animals. Several species climb trees with ease, and all swim well, especially the polar bear.

Bears are powerful animals, and they can be very dangerous to people who get too close to them. Some species, especially polar bears and grizzlies, have been known to attack people. However, bears generally do not attack humans unless they are surprised or feel trapped or that their young or food supplies are threatened.

Except during the mating season, bears tend to live solitary lives. They prefer to roam in areas undisturbed by humans. Most tend to stay within certain territories. The size of a bear’s home range varies depending on the availability of food in the area, as well as its species and sex. A male American black bear, for instance, may roam an area of about 15 to 75 square miles (40 to 200 square kilometers). The females have much smaller ranges. On the other hand, some polar bears must travel very far in search of food and may roam ranges of more than 50,000 square miles (125,000 square kilometers).