Black bears frequent heavily forested areas, including large swamps and mountainous regions. Mixed hardwood forests interspersed with streams and swamps are typical habitats. Highest growth rates are achieved in eastern deciduous forests where there is an abundance and variety of foods. Black bears depend on forests for their seasonal and yearly requirements of food, water, cover, and space.

Black bears are omnivorous, foraging on a wide variety of plants and animals. Their diet is typically determined by the seasonal availability of food. Typical foods include grasses, berries, nuts, tubers, wood fiber, insects, small mammals, eggs, carrion, and garbage. Food shortages occur occasionally in northern bear ranges when summer and fall mast crops (berries and nuts) fail. During such years, bears become bolder and travel more widely in their search for food. Human encounters with bears are more frequent during such years, as are complaints of crop damage and livestock losses.

Back bears are powerful animals that have few natural enemies. Despite their strength and dominant position, they are remarkably tolerant of humans. Interactions between people and black bears are usually benign. When surprised or protecting cubs, a black bear will threaten the intruder by laying back its ears, uttering a series of huffs, chopping its jaws, and stamping its feet. This may be followed by a charge, but in most instances it is only a bluff, as the bear will advance only a few yards before stopping. There are very few cases where a black bear has charged and attacked a human. Usually people are unaware that bears are even in the vicinity.