Wolverine

The largest weasel-family member, so rare in Washington that a 2020 den at Mount Rainier was its first confirmed wolverine family in over a century.

Wolverine at a glance

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Type
Mammal · mustelid
Diet
Carnivore
Size
A male wolverine weighs about as much as a medium-sized dog (26 to 44 pounds / 12 to 20 kg); a female is smaller (18 to 27 pounds / 8 to 12 kg). Nose to tail it runs about as long as a baseball bat, with a thick, bushy tail.
Lifespan
Few wolverines live past 5 to 7 years in the wild, though a handful reach 12 or 13.
Conservation
Threatened

Eats marmots, ground squirrels, hares, porcupines, old carcasses from wolves and bears

In summer a wolverine hunts and digs for smaller animals like marmots, ground squirrels, and hares. In winter it switches almost entirely to scavenging, tracking down carcasses other predators left behind, dragging pieces away, and caching them in cold ground or snow to eat later.

Should you worry?

Not a real worry. Wolverines are shy and solitary and go out of their way to avoid people. Mount Rainier's own wildlife biologist has said publicly that despite their fierce reputation in movies and cartoons, they pose no risk to park visitors. They're also so rare in Washington that spotting one at all would be the surprising part. Give any wild animal room, never approach a den, and keep food packed away.

A trail camera bolted to a tree in the high country of Mount Rainier fires in the dark, and the flash catches an animal paused mid-step in the snow: low and stocky, dark fur, a pale blaze of cream fur across its chest. That was August 2020, and the photograph, backed up by DNA from hair caught on the same camera station, confirmed something biologists hadn’t been able to say about the park in more than a hundred years: a female wolverine was denning there, with two kits.

Researchers tell individual wolverines apart by that chest blaze, a marking as particular to each animal as a face, built up over years of camera stations and hair snags strung through the Cascades. Washington’s whole wolverine population is guessed at fewer than 25 animals, so every blaze photographed is a name added to a very short list. This one, they’d later learn, had first turned up on a camera in late 2019. By 2021 a second litter confirmed she’d settled in for good, only the third wolverine family documented in the South Cascades in a century.

A wolverine’s jaw and back teeth are strong enough to crack bones and frozen meat nothing else touches, which is how it gets through winter: scavenging a carcass a wolf or bear left behind, dragging pieces off, and burying them in the snow to eat weeks later across a territory that can run past 700 square miles. In 2023, with fewer than 50 wolverines estimated left in the entire contiguous United States, the population was listed as threatened. You will almost certainly not see one on a trail. If you find a set of tracks crossing untouched snow at treeline and going somewhere no trail does, that is who left them.

Did you know?

  • A wolverine can smell a carcass buried under several feet of snow and dig straight down to it.
  • Wolverines are built low and stocky for their size, but they're really the largest member of the weasel family, closer kin to otters, martens, and badgers than to bears or wolves.
  • Washington's entire wolverine population is estimated at fewer than 25 animals, which is what made the 2020 discovery of a breeding female at Mount Rainier such a big deal for the biologists tracking the species' slow return.

Common questions

Are wolverines dangerous to people?

No. They are shy, solitary animals that avoid people whenever they can. A Mount Rainier wildlife biologist has said directly that wolverines pose no risk to park visitors, despite how fierce they look in movies.

Is a wolverine a kind of wolf or bear?

Neither. It's the largest member of the weasel family, more closely related to otters and martens than to wolves or bears, even though it's built low and stocky like a small bear.

How rare are wolverines in Washington?

Very. Biologists estimate fewer than 25 wolverines live in the whole state, mostly in the high country of the North Cascades and around Mount Rainier.

What do wolverines eat?

Marmots, ground squirrels, and hares in summer. In winter they mostly scavenge carcasses left by wolves, bears, or bad weather, using teeth strong enough to crack frozen bone.

Where it lives

Where we got this