It can be affected by spring shedding, growth of new hair, nutrition, and climate. Coat colour is not a good characteristic for distinguishing between black and grizzly bears. Other external physical features are much more useful. The grizzly has a large hump over the front shoulders. This hump is a muscle mass used to power forelimbs in digging.
Grizzlies have a large rounded head with a concave facial profile.
The small rounded, furred ears are set well apart on the head in contrast to its narrowly set eyes. The black bear, on the other hand, has no shoulder hump and has a long, straight facial profile and large ears. Tracks and claws also distinguish the two species. Grizzly claws are much longer and the toes are close together in a relatively straight line, while a black bear's toes are splayed in a more rounded arc. In general, but not invariably, grizzlies are larger than black bears.