Gray Wolf

The largest wild member of the dog family, once the most widely distributed land mammal on Earth, ranging across most of North America, Europe and Asia before extensive persecution eliminated it from much of that range in the nineteenth and twentieth centuries. Gray wolves live in cooperative family packs built around a breeding pair and their offspring, hunt large prey such as elk, deer and moose in coordinated groups, and communicate through howling, body posture and scent marking. As an apex predator, the wolf's reintroduction to Yellowstone National Park in 1995, after a seventy-year absence, is one of the best-documented examples of a single species reshaping an entire ecosystem, altering elk grazing behavior in ways that allowed streamside vegetation and, with it, beaver populations to recover.