Wolverine — The wolverine (Gulo gulo) is the largest land-dwelling species of the Mustelidae or weasel family (the Giant Otter is largest overall), and is the only species currently classified in the genus Gulo (meaning “glutton”). It is also called the Glutton or Carcajou. Some authors recognize two subspecies: the Old World form Gulo gulo gulo and the New World form G. g. luscus. A third subspecies limited to Vancouver Island (G. g. vancouverensis) is also occasionally described. However craniomorphic evidence suggests that the Vancouver Island wolverines are properly included within G. g. luscus.
The wolverine is, like most mustelids, remarkably strong for its size. It has been known to kill prey as large as moose, although most typically when these are weakened by winter or caught in snowbanks. Wolverines inhabiting the Old World (specifically, Fennoscandia) are more active hunters than their North American cousins. This may be because competing predator populations are not as dense, making it more practical for the wolverine to hunt for itself than to wait for another animal to make a kill and then try to snatch it.
Armed with powerful jaws and a thick hide, wolverines may defend kills against larger or more numerous predators. There is at least one published account of a 27-pound wolverine’s attempt to steal a kill from a much larger predatorâ€”namely, a black bear (adult males weigh 400 to 500 pounds). Unfortunately for the mustelid, the bear won what was ultimately a fatal contest, crushing the wolverine’s skull.