Stay with mother until 1.5 to 2.5 years old, then disperse. Females ready to reproduce at 3 or 4 years. Usually have twins every other year, or two litters in 3 years. Average age span is about 10 years, but no bear has ever been known to die of old age. Of all the radio collared bears in Maine, all have died from accident, automobiles, hunters, other bears etc.
Weights vary between parts of country, time of year and food supply.
Typical Maine female weighs about 150 pounds, male about 250. In other parts of country typically get 300-400 pounders. Dens may be a hollow log or simply a thick clump of conifer growth, or under roots of a partially overturned tree. Bears are solitary and territorial. Males have large territories covering several female territories.