The hump above a grizzly's shoulders is skeletal muscle attached to unusually long spinous processes on the thoracic vertebrae. That anchorage gives the forelimbs a long lever arm and a great deal of pulling power, which the bear applies to excavating ground squirrels, turning boulders and digging roots and bulbs out of hard alpine soil. The front claws, often 5 to 10 centimetres long and only weakly curved, are shaped for the same work.
Black bears lack the hump and carry shorter, strongly curved claws better suited to climbing tree bark. Field guides across North America use hump presence, claw length and facial profile rather than coat colour to separate the two, because both species range from blonde through cinnamon to near-black.
Despite the equipment, most grizzly diets are dominated by vegetation. Studies across interior populations regularly find plants, roots and insects making up the majority of intake by mass, with meat concentrated in salmon runs, ungulate calving seasons and scavenged carcasses. How much a given population depends on meat varies enough that estimates from one range travel badly to another.