When standing on four legs, adults are 3 ' to 4 ' tall at the hump. To improve their opportunity to see and smell, bears may rear up on their hind legs to more than 8 feet in height. The distinctive hump over the grizzly bear's front shoulders is a mass of muscle. That and its long claws enable the grizzly to dig for roots or bulbs or small burrowing mammals. Grizzlies can move boulders weighing hundreds of pounds.
Grizzlies rely primarily on their size and aggressiveness to intimidate most other animals.
Although it is often said that grizzly bears can't climb trees, this is not entirely true. Stories that bears cannot swim or run downhill are also incorrect. The size of a grizzly's home range varies depending on the age and sex of the bear and the quality and quantity of habitat available. Male grizzlies in the Yellowstone area have home ranges averaging 337 square miles. Female ranges are considerably smaller, averaging 108 square miles.