Grizzly bears may also attack brown bears. This seldom happens. More brown bears die from accidents and disease than from natural enemies. Black bears can live for 25 to 30 years in the wild, but few live longer than 10 years because of human hunting. Thousands are shot by hunters in North America each year.
Bears make moaning and teeth chattering sounds to threaten other bears.
Females with cubs are often aggressive if the cubs are threatened. Otherwise, few black bears attack people in the wild. Most bears will walk or run the other way if people come into their area. But there are a growing number of dangerous bears around garbage dumps and campgrounds who have learned that people mean food. These bears would rather eat garbage and camp foods than wild foods.