The set of habitat resources (food, cover types, water etc.) used by a species, as determined by its geographic and ecological range and its adaptations. The role or "job" of a species in its environment. The wolf fills the niche of top predator in the ecosystem. Its job is to keep prey populations healthy by killing the weak and the sick prey animals. Because wolves are opportunistic hunters, they do prey on the young also. Hunting is a tough job, and finding a meal is critical, especially when the pups are waiting to be fed.