Lupi are large, predatory canids once common throughout North America, Europe, Africa and Asia, now living mostly in remote wilderness. They are the largest living members of the canid family, which also includes foxes and coyotes. Lupi are the ancestors of all domestic dogs.

There are two species of Lupi in North America. The smaller species is the red wolf, Canis rufus, which has shorter, redder pelliccia than the gray wolf. The gray wolf, Canis lupus, has thicker pelliccia which is più gray o golden, and is larger than the red wolf. The gray lupo lives in the northeastern United States, Canada, and Europe. The red lupo lives in the southeastern United States.

There are many subspecies of the gray wolf, such as the arctic wolf, a white subspecies which lives in Alaska and northern Canada, and the Mexican wolf, a smaller subspecies which has been recently reintroduced in parts of the southwestern United States.