Wolverine - Behavior

Behavior

The wolverine is a powerful and versatile predator and scavenger. Prey mainly consists of small to large-sized mammals and the wolverine has been recorded killing prey such as adult deer that are many times larger than itself. Prey species include porcupines, squirrels, beavers, marmots, rabbits, voles, mice, shrews, lemmings, caribou, roe deer, white-tailed deer, mule deer, sheep, moose, and elk. Smaller predators are occasionally preyed on, including martens, mink, foxes, Canada lynx, weasels, Eurasian lynx, and coyote and wolf pups. Wolverines often pursue live prey that is relatively easy to obtain, including animals caught in traps, newborn mammals and deer (including adult moose and elk) when they are weakened by winter or immobilized by heavy snow. Their diets are sometimes supplemented by birds' eggs, birds (especially geese), roots, seeds, insect larvae and berries. A majority of the wolverine's sustenance is derived from carrion, which they depend on almost exclusively in winter and early spring. Wolverines may find carrion themselves, feed on it after the predator is done feeding (especially wolf packs) or simply take it from another predator. Whether eating live prey or carrion, the wolverine's feeding style appears voracious, leading to the nickname of "glutton" (also the basis of the scientific name). However, this feeding style is believed to be an adaptation to food that is scarcely encountered, especially in the winter.

Armed with powerful jaws, sharp claws, and a thick hide, wolverines, like most mustelids, are remarkably strong for their size. They may defend kills against larger or more numerous predators. At least one account reported a 12-lb wolverine's apparent attempt to steal a kill from a black bear (adult males weigh 400 to 500 lb (180 to 230 kg). Unfortunately for the mustelid, the bear won what was ultimately a fatal contest. Another account placed a polar bear of unknown age and weight together with a similar wolverine where the smaller, tenacious predator came out the victor. Interestingly, while wolverines have dominated wolves in competitions over a carcass, some wolves become habituated to preying on wolverines and, in such cases, wolves may lead to a complete absence of wolverines in a given area.

Wolverines inhabiting the Old World (specifically, Fennoscandia) are more active hunters than their North American relatives. This may be because competing predator populations in Eurasia 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. They often feed on carrion left by wolves, so changes in the population of wolves may affect the population of wolverines. Wolverines are also known on occasion to eat plant material.

Successful males will form lifetime relationships with two or three females, which they will visit occasionally, while other males are left without a mate. Mating season is in the summer, but the actual implantation of the embryo (blastocyst) in the uterus is stayed until early winter, delaying the development of the fetus. Females will often not produce young if food is scarce. The wolverine gestation period is 30–50 days. Litters of typically two or three young ("kits") are born in the spring. Kits develop rapidly, reaching adult size within the first year of a lifespan that may reach anywhere from five to (in exceptional individuals) 13 years. Fathers make visits to their offspring until they are weaned at 10 weeks of age; also, once the young are about six months old, some reconnect with their fathers and travel together for a time.