As apex predators, grizzly bears have no natural enemies in the wild. The only real threat to the grizzly bears' existence is human interference. Hunting and habitat loss have dramatically reduced grizzly bear numbers in North America.
The grizzly bear, a large North American subspecies of the brown bear, can grow up to 8 feet in height and weigh over 800 pounds. Although the grizzly bear is capable of preying on large mammals such as moose, it is an opportunistic feeder and consumes a wide variety of vegetation as well. In the winter, grizzly bears find suitable dens in which to hibernate. Pregnant females usually give birth during this time.