Outdoors portrait titleWolverine



Gulo gulo

By Brian Giddings

FWP wildlife technician Mike Ross and I brought our snowmobiles to a sudden stop at the sight of large tracks crossing the forest road. The inch of fresh snow had produced perfect conditions for our winter furbearer track survey. Upon closer examination, we saw that the nearly 5-inch-wide bearlike tracks revealed five toes, each with a claw mark, a chevron-shaped footpad, and an additional heel pad. It was the track of a wolverine, one of the most legendary and elusive furbearers in North America.

At a glance, a wolverine looks like a small bear. It has a thick body, short legs, short ears, and a broad, flat head. But the similarity ends there. Wolverines have an arched back and a foot-long, bushy tail. They weigh between 15 and 30 pounds and vary in length from 36 to 44 inches, tail included. Males are typically one-quarter larger than females. Wolverines are active all year and do not hibernate. During winter, a wolverine’s coat becomes long and dense and its feet are covered with stiff hair that helps it walk on snow. The wolverine’s fur is dark brown to black, with light brown to yellowish stripes running from each shoulder along the flanks to the base of the tail, and white markings on the chest. The wolverine has large teeth and thick, long, non-retractable claws used for digging, holding prey, and climbing trees.

Also known as devil bear and skunk bear in various parts of northern North America, the wolverine is the largest member of the weasel family. Its scientific name, Gulo gulo, is Latin for glutton and refers to the animal’s eating habits. Wolverines are extraordinarily powerful animals that can quickly dig a tunnel through 8 feet of snow to reach a frozen animal carcass.

Viselike jaws can easily crush elk and deer bones. They also have a keen sense of smell and exceptional hearing, though their eyesight is poor compared to that of deer and elk. A wolverine has tremendous physical endurance and may travel 30 to 40 miles a day in search of food. Active primarily at night, this solitary creature requires a large territory of up to 400 square miles.

Food habits
An opportunistic feeder, the wolverine eats about anything it can find, from berries and nuts to small animals and even big game. Its main food source is carrion, especially during winter and spring. Many deer and elk that die in winter are eventually found by wolverines, which will eat their fill and then drag the carcass—up to five times their own weight—to a cave or other cache site. Vicious fighters, a wolverine will savagely defend a kill or carcass, driving off wolves and even grizzly bears. Wolverines prey on marmots, ground squirrels, snowshoe hares, porcupines, grouse, and occasionally mice and voles.

Like all members of the weasel family, wolverines reproduce by what is called delayed implantation. Females breed in summer, but the embryos don’t implant for several months, finally developing into fetuses in early winter. Birth takes place a few months later, in late January through April. One to three young are born under deep snow in dens containing tunnels up to 180 feet long. Young wolverines, called kits, develop rapidly and are weaned within two months. Roughly four months later, the young wolverines begin foraging for themselves. Wolverines attain most of their adult size and weight within their first year.

Montana maintains a healthy wolverine population due to the state’s abundant wilderness areas, national parks, and roadless lands, which serve as refuges for this solitary species. Snow track surveys and harvest records indicate that wolverines also live in nearly all mountain ranges in western Montana, even those with roads, ski slopes, and other development. Apparently, the wolverine tolerates human activity as long as it has enough mountainous, forested habitat and can fill its belly. New research is investigating the relationships between wolverines and winter recreation, timber harvest, rural development, and trapper harvest.

Montana is the only state other than Alaska to provide a resident wolverine season. Over the past 25 years, the state’s healthy, well-distributed population has allowed for a consistent average yearly harvest of 10 wolverines. FWP biologists examine the pelts and carcasses of all harvested animals to determine their age, sex, genetic makeup, reproductive history, and condition.

Trappers prize the wolverine because of its rarity, elusiveness, and place in the lore of wilderness trapping and hunting. The dense guard hairs don’t accumulate frost, making the fur highly valued for parka hood trim, especially in Russia and China. Most trappers lucky enough to capture a wolverine tell me they have it mounted to preserve the image of an animal that symbolizes the harsh, wild conditions of the North American Rockies.Bear bullet