Wolverine
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 fur-bearer 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.
Appearance
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.
Behavior
Also known as devil bear and skunk bear in various parts of northern North
Am-erica, 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.
Reproduction
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.
Management
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.
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