Glotón (Sp), Vielfrass (G), Glouton (F). Sometimes called glutton, in reference to its supposed eating habits.
DESCRIPTION Head and body length 25-40 inches (64-102 cm). Tail length 7 to 10.2 inches (18-25 cm). Shoulder height 15-18 inches (38-46 cm). Weight 22-50 pounds (9-23 kg). Females measure 10 percent less than males and weigh 30 percent less. Chromosome count 42.
The wolverine is the largest land-dwelling member of the weasel family and looks something like a small bear except for its relatively long tail. It is short and heavy with short, massive legs and large paws. The ears are small and rounded. The fur is long and thick, blackish-brown in color, with light patches on the crown and cheeks, and yellowish flank bands that extend from shoulders to rump and join across the base of the tail. The jaws are powerful and the premolars are heavy, for crushing bones. Wolverines have 38 teeth (i3/3, c1/1, pm4/4, m1/2). There are five toes with large, curved, non-retractile claws on each foot. The soles are naked in summer, densely haired in winter.
BEHAVIOR Solitary except when breeding, and nowhere numerous. Large individual territories are established, where same-sex individuals are usually not tolerated. Territories are regularly marked with urine and secretions from the anal scent glands. Breeds late April-July, with delayed implantation until November-March, followed by 30-40 days active gestation, and births occurring during January-April. Litter size is usually 2-4, range 1-5. The young leave their mother that fall, are fully grown at one year and sexually mature at 2-3 years. Life span has been recorded at 13 years in the wild, 18 years in captivity.
Largely nocturnal, but sometimes active in daylight. May alternate 3-to-4 hour periods of activity and sleep in the far north where there are long periods of light and darkness. Mainly terrestrial, but is a good tree climber and good swimmer. Sense of smell is good, eyesight poor, hearing indifferent. The wolverine is exceptionally strong for its size and has been reported as driving bears and cougars from their kills. Runs at a loping gallop, which it can maintain for many miles without rest. Has been known to travel as far as 28 miles (45 km) in a day. For shelter, it builds a bed of leaves or grass in a cave or rock crevice, under a log or in a hole under snow. Does not hibernate. Feeds on rodents, birds, fruit, berries, eggs and carrion. Some larger mammals are also killed, usually in winter when snow allows the wolverine to travel faster than its prey. Caches any surplus food by covering with earth or snow, or places in forks of trees.
HABITAT Arctic and subarctic tundra and forest.
DISTRIBUTION Once found from Scandinavia and Germany eastward to the Pacific Ocean, and throughout North America as far south as the southern parts of California, Utah, Colorado, Illinois, Indiana and Pennsylvania. Now restricted to parts of northern Scandinavia and northern Russia in Europe. Still common across Siberia and extending into Mongolia and Manchuria.
In North America, it remains widespread in Alaska, western and northern Canada and northern Greenland, and still occurs in parts of Washington, Oregon, California, Idaho, Montana, Wyoming and Colorado. Also possibly in South Dakota, Minnesota and Iowa.
REMARKS The wolverine is trapped to some extent in Alaska, Canada and Montana, but the fur has little commercial value other than for parkas in arctic regions, because it accumulates little or no frost. Considered a pest worldwide because of its habits of following traplines and eating trapped animals, of breaking into cabins and food caches and befouling the contents with its anal scent glands after eating its fill, and of preying on domestic reindeer. As a sports trophy, it usually is taken as a target of opportunity while hunting other species. Tracking by snow machine is an option in some areas. Only wolverines that have been hunted-not trapped-are eligible for the Record Book.
TAXONOMIC NOTES Although some authorities treat the wolverines of North America as a separate species (Gulo luscus) from those of Eurasia (G. gulo), most accept only one species (G. gulo) worldwide, and this is how we treat them as well. Four subspecies have been listed in North America, but we do not separate them.
STATUS Listed as vulnerable by the IUCN and as endangered in eastern Canada.