Black bears tend to live until their early 20s in the wild, although some have been known to live as long as 30 years. Black bears are born in the winter, at which point they are blind and weigh an average of 7 ounces.
Newborn cubs grow quickly while nursing in their mother's den, thanks to the rich milk their mothers provide them.
In the spring, when a black bear is a few months old, it weighs 10 pounds and begins to follow its mother, learning from her how to find food. Mother bears wean their young when the cubs are 6 to 8 months old. However, they remain with their mother through the winter, leaving the next spring to stake out their own territory.
Young female black bears generally stay near their mother's den, while young males move further away. There is a higher mortality rate among young male black bears than young female black bears, since full-grown male black bears kill and devour young males when they find them alone and far from home.
During times when food sources are abundant, female bears give birth to one to five cubs every other year. During lean times, however, black bears are known to go several years before giving birth to another litter.