The Mexican gray wolf is a subspecies of the gray wolf, commonly referred to as “el lobo”.

Though they once numbered in the thousands, these wolves were wiped out in the U.S. by the mid-1970s, with just a handful existing in zoos. In 1998, the U.S. Fish and Wildlife Service, led by Jamie Rappaport Clark (now president of Defenders of Wildlife), released 11 Mexican gray wolves back into the wild in Arizona.

Although their numbers have grown slowly, they remain the most endangered subspecies of wolf in the world because of compromised genetics, human intolerance and reluctance to release more individuals and bonded pairs to the wild.