Found across the boreal forests and northern tundra of Canada, the wolverine is the largest land-dwelling member of the weasel family. Early French-Canadian trappers called it "carcajou," while its English name hints at the fierce, greedy reputation it has carried for centuries. Despite that reputation, the wolverine shares many features with its smaller relatives, the badgers, martens, and otters: a stocky body, short legs, and dense fur. That fur, which resists frost and does not hold moisture, has long been trapped and prized in the North for lining the hoods of parkas.

The wolverine's most distinctive feature lies inside its mouth. A special upper molar is turned roughly ninety degrees from the usual position, allowing the animal to tear into meat and bone frozen solid through the winter, a meal few other predators can manage. Its broad paws spread under its weight like snowshoes, carrying it over deep drifts. Males are noticeably larger and heavier than females, sometimes by a third, though the two are otherwise hard to tell apart.