Grizzly bears have well-developed shoulder muscles for digging and turning over rocks. These muscles appear as a prominent shoulder hump.
Black bears lack the well-developed shoulder muscles and therefore do not have the shoulder hump.
Caution: The bear's position can affect your ability to see the hump. For example, a black bear may appear to have a hump if it’s standing on a rock or log. A grizzly bear’s hump may not be obvious if its head is raised above shoulder level.