In summer, they also become active during the day and in fall they may be active day and night. Some bears may move far from their usual home range, particularly in the fall when searching for acorns. If mast production is good you will generally find bears staying or bedding down near the food source and water. Bears mark trees by clawing and chewing the bark of certain trees. Those mark trees are usually found along trails and animals paths often used by bears.
Black bears are solitary, except for mothers with offspring.
A dominance hierarchy may exist where food is abdundant. During the mating season, males may fight to establish access to estrous females. Bears have color vision and keen sense of smell, are good tree climbers, swim very well and can run up to 30 miles per hour. Due to the heavier weight they may have problems climbing a tree in a hurry. Bears eat mostly berries, nuts, animal carrion, grubs, and insect larvae.