Wolverines are giant relatives of the weasels and, along with the giant otter, they are the largest mustelids in the world. The name wolverine primarily refers to the North American population. In northern Europe and Siberia, the animals are also known as gluttons due to their liberal feeding habits and voracious appetites. It is both a formidable hunter and scavenger.
Wolverines are generally nocturnal but will forage by day if they need to. Their diet varies throughout the year. In summer, they feed on small animals, such as mice and other rodents and ground-living birds, such as pheasants. They also readily feast on summer fruits.
In winter, when most other carnivores are hibernating or sheltering from the cold, wolverines may tackle bigger prey, even something as large as a moose, which is 20 times the size of the predator. The wolverine's wide feet act as snowshoes, allowing them to walk over deep snow, in which hapless deer or wild sheep are easily bogged down, becoming defenceless and unable to make their escape.
Wolverines have large heads and heavily built bodies with dense coats of hairs of different lengths to prevent winter snow and ice from getting too close to the skin, causing heat loss.
Individuals roam over very large territories - that of a male can cover an area up to 620 square kilometer (240 square miles). Females have a territory of up to 260 square kilometer (100 square miles). Wolverines mate in early summer and young are born in underground dens the following spring. They are weaned at ten weeks and leave their mothers in the autumn.
Distribution: Circumpolar, occurring through northern latitudes in North America, extending down the west coast into the USA, and across the far north of Europe and Asia.
Habitat: Tundra and conifer forest.
Weight: 22 - 36 kg (49 - 79 lb); males are heavier.
Length: 82 - 113 cm (32 - 44 in); up to 43 cm (17 in) tall.
Maturity: 1 - 2 years.
Gestation Period: About 50 days; embryonic development does not begin straight after fertilization.
Breeding: 2 - 3; weaning occurs at around 70 days.
Food: Will steal from other predators such as wolves, and hunts prey up to the size of a moose.
Lifespan: 10 - 13 years in the wild; up to 18 in captivity.
The small ears are well-insulated by fur.
Brown with yellow streaking on the flanks, the thick fur offers good protection against the cold.
A rotated molar tooth is present at the back of each jaw, serving to crush bones and strip frozen meal carcasses.
The feet are equipped with formidable claws, used for fighting and ripping apart prey.
Old World wolverines are forced to hunt more frequently than their New World counterparts, as there are fewer opportunities to scavenge.