The Gray Wolf (Canis lupus; also spelled Grey Wolf, see spelling differences; also known as Timber Wolf or Wolf) is a mammal in the order Carnivora. The Gray Wolf shares a common ancestry with the domestic dog (Canis lupus familiaris), as evidenced by DNA sequencing and genetic drift studies. Gray wolves were once abundant and distributed over much of North America, Eurasia, and the Middle East. Today, for a variety of human-related reasons, including widespread habitat destruction and excessive hunting, wolves inhabit only a very limited portion of their former range. Though listed as a species of least concern for extinction worldwide, for some regions including the Continental United States, the species is listed as endangered or threatened.