Wolves eat a wide variety of prey, large and small. They efficiently hunt large prey that other predators cannot usually kill. In Yellowstone, 90% of their winter prey is elk.

The prey base in Yellowstone National Park is diverse, supporting one of the most complex predator-prey systems in the world. The primary large prey is the Elk, which makes up roughly 90% of a wolf's winter diet. Other major ungulate (hoofed) prey include Bison, Mule Deer, White-tailed Deer, Moose, Bighorn Sheep, and Pronghorn. While bison are formidable and dangerous to hunt, they are a vital food source, especially for grizzly bears and larger wolf packs. Smaller prey animals also play a crucial role in the ecosystem; Uinta Ground Squirrels, Snowshoe Hares, Beavers, and various rodents provide sustenance for smaller predators like coyotes, foxes, and raptors. The "predatory-prey dance" in Yellowstone is a constant cycle that keeps the grasslands healthy and the wildlife populations in a delicate, natural balance.