Both black and grizzly bears are frequently encountered in and around Yellowstone Park, and both species are unpredictable. Since it can be difficult to tell the two species apart, hikers are best advised to be wary of all bears. As a rule, black bears are generally smaller, less aggressive animals and most have black or dark brown hair. Adult grizzlies, on the other hand, are quite large with lighter-colored hair that is usually highlighted by silver tips, giving the animal a distinctive sheen. The only true distinction between the two species is their body shape, the shape of their muzzles and their claws.
Grizzlies have a hump above their front shoulders, making it the highest point in their body.
On black bears the highest point is the rump. In a profile, the grizzly's face has a distinctive brow that gives the bear a dish-shaped muzzle. The black bear has a straight muzzle and the face appears round when viewed from the front. Finally the grizzly bear has much larger claws Bears are found in the Yellowstone area. than black bears. Grizzly claws are several inches long and when the bear leaves a footprint, the claw impressions are about two to three inches in front of the pads.