The wolverine is the largest terrestrial member of the Mustelid family, which also includes Weasels, Badgers, Otters, Ferrets, and Minks. It has a broad head, small eyes and short rounded ears. Its body is covered in oily, dark brown fur, which makes it resistant to frost. It often has a lighter-coloured face mask and stripe running down both sides of its body as well. Typically weighing less than 35 pounds, wolverines are nonetheless powerfully built, having strong, short legs with wide feet ideal for traveling across the snow. Wolverines also have special upper molars in the backs of their mouths that are rotated 90 degrees, allowing them to tear off meat from prey or carrion that has been frozen solid.
Wolverine are omnivores that prefer meat, and they are proficient and versatile both as predators and scavengers. Mainly preying on small- to medium-sized mammals such as porcupines, squirrels, beavers, marmots, rabbits, voles, mice, shrews, and lemmings, they are also capable of preying upon adult deer, caribou, moose, sheep, and elk that are many times larger than themselves. They usually pursue the live prey that are most easy for them to obtain, such as animals that have been trapped, undeveloped young mammals, and animals that have been encumbered by heavy snow. In addition to their most common kills, their palates are at times satisfied by supplementations of fowl, eggs, tubers and roots, nuts and seeds, fruits and berries, and other forms of plant matter.
Habitat and Range
Wolverines can only be found amidst boreal forests, taiga, and tundra all throughout the subarctic latitudes of Eurasia and the New World alike. Those living in the Lower 48 Contiguous United States tend to live in the most rugged and remote areas, spending most of their time at high elevations, at times above the timberline. Further north into Alaska and Canada, wolverines can be found within a wide variety of elevations and subarctic habitats, including boreal forests, tundra and Western mountains. Due to excessive trapping and habitat fragmentation, their range has seen a marked reduction and their populations have suffered steady declines since the 19th Century. Nonetheless, the International Union for the Conservation of Nature has listed their species as having a conservation status of "least concern" of becoming endangered or extinct.
Wolverines are typically very solitary and territorial animals, and therefore need a lot of room to roam. Individual wolverines may travel as far as 15 miles (24 kilometres) in a single day in search of food sources. As a result, they defend large, gender-exclusive territories that they mark with their urine. However, they do also have a social side, though not to the extent of forming large-scale communities. Male and female territories usually overlap, and mating pairs and their litters share very strong family bonds. In fact, parents will maintain strong ties with their kits even after they have reached adulthood. Due to the warmth provided by their extremely dense fur, and the large paws akin to snowshoes that allow them to cover snow and frozen terrain efficiently, they do not hibernate, and stay very active during the winter months.
Dominant males will form life-long mating relationships with two or three female partners which they will maintain throughout breeding seasons, while other males are left totally lacking a mate of their own. The mating season typically runs throughout the summer, though the embryo is not developed until early winter due to a mechanism of "delayed" implantation of the embryo into the uterus in a process known as "Embryonic diapause". After a gestation period between 30 to 50 days, impregnated female wolverines will give birth to a litter of two or three kits in early spring in dens that provide security and a buffer to cold weather. Kits are born pure white and with their eyes closed. Following birth, wolverines develop rapidly, reaching mature sizes within their first year.