How Strong Is a Wolverine? Facts Behind Its Fierce Reputation

How big and how strong is a wolverine?

The wolverine (Gulo gulo) is the largest land-dwelling member of the weasel family. Males usually weigh 11–18 kg (24–40 lb) and females 8–12 kg (18–26 lb). Their head and body length is 65–105 cm (26–41 in), with a short, bushy tail.

What makes the wolverine strong is its build rather than its size. It is short-legged, thick-necked and heavily muscled, with a broad skull that anchors big jaw muscles. Its large feet carry long, curved, semi-hooked claws that it uses to dig through snow, climb trees and cliffs, and hold onto prey. People who handle wolverines for research describe them as surprisingly dense and powerful for their size.

Jaws that crunch frozen bone

The wolverine’s best-known strength is in its jaws. Like other members of the weasel family, it has powerful jaw muscles, and an upper molar at the back of the mouth is turned sideways, at about 90 degrees to the other teeth. This unusual tooth helps it shear meat and tendons that are frozen solid.

For an animal that lives largely on carcasses in Arctic and mountain winters, that matters. A reindeer or moose that died weeks ago may be frozen as hard as wood. Wolverines can chew through frozen hide, meat and bones that many other scavengers leave behind, which means they waste very little. You will sometimes see a precise bite-force figure quoted for wolverines online, but no widely accepted measurement exists for wild animals, so treat such numbers with care.

Can wolverines kill large prey?

Yes, under the right conditions. Most of the large animals a wolverine eats are carrion, but it is also a capable predator. In Scandinavia, wolverines regularly kill semi-domesticated reindeer, especially in late winter when the snow is deep and soft. In North America they have been recorded killing caribou, deer, Dall sheep and occasionally moose.

Snow is the key. A wolverine’s wide, furry feet spread its weight like snowshoes, so it can run on top of soft snow while a heavy hoofed animal breaks through and sinks. A reindeer weighing several times as much as the wolverine can be caught, held and killed with bites to the neck. On bare ground in summer, wolverines mostly hunt smaller animals such as marmots, ground squirrels, hares and birds. More on its menu is in what do wolverines eat?.

Dragging, digging and caching

Wolverines are tireless carriers. They have been seen pulling and dragging carcasses and large pieces of meat over long distances and up steep slopes to hide them. They tear carcasses apart and bury the pieces in snow, under rocks or in boggy ground, then return to them for weeks or months.

They are also powerful diggers. Wolverines can locate a carcass buried under deep snow by smell and dig straight down to it. Females dig breeding dens in the snowpack that may include tunnels several meters long. In Glacier National Park, Montana, a tracked male climbed roughly 1,500 m (4,900 ft) up a steep mountain face in about 90 minutes, a feat of stamina as much as strength.

Do wolverines really fight bears and wolves?

There are many observations of wolverines standing their ground against much larger predators at a carcass. A wolverine will hiss, growl, bare its teeth and charge, and sometimes this is enough to make a wolf, a lynx or even a bear back off. Biologists and hunters in Alaska, Canada and Scandinavia have reported such encounters.

But the wolverine does not always win. Gray wolves are one of the main natural causes of death for wolverines in many areas, and packs kill them at carcasses and near dens. Bears and cougars can also kill wolverines. In reality, the bold behavior is a bluff that works often enough to be worth the risk for an animal that depends on scavenging other predators’ kills.

Why is the wolverine so fierce?

The wolverine’s toughness is an answer to a hard life. It lives in places where food is scarce for months, and it must travel huge distances to find it. Males often cover home ranges of 500–1,500 km² (190–580 sq mi) and can travel 30–45 km (19–28 mi) in a day through snow and mountains. An animal in that situation cannot afford to give up a carcass easily, and it cannot afford to waste anything it finds.

Its reputation for fury also comes from how it behaves when trapped or cornered. Like most mustelids, a threatened wolverine growls, snarls and releases a strong musky smell from its anal scent glands. Early fur trappers, whose traps and food stores wolverines were known to raid, helped spread stories of a “devil” of the north woods.

Myths about wolverine strength

Myth: a wolverine can kill a grizzly bear. There is no reliable record of a wolverine killing a healthy adult grizzly. A brown bear can weigh 15–30 times as much as a wolverine.

Myth: wolverines are mindless gluttons. The scientific name Gulo means “glutton”. Wolverines do eat fast and store a lot, but this is food insurance for winter, not greed.

Fact: they are among the toughest animals of the north. Wolverines stay active all winter without hibernating, live in some of the coldest and steepest terrain in North America and Europe, and survive by a mix of hunting, scavenging and sheer persistence. Other hardy northern species are featured in our list of Arctic animals.