Monitoring the comeback of one of North America’s rarest wild animals

A wolverine sniffs lure at a remote camera site outside Leavenworth, Washington. Photo: CNW / Citizen Wildlife Monitoring Project

Latest News May 2022: Court Restores Wolverine Protections While Agency Reconsiders Endangered Species Decision


Wild icons of North America, wolverines (gulo gulo) are seldom-seen carnivores that favor remote, rugged, snowy landscapes, often in alpine and subalpine areas.
Wolverines are the largest terrestrial members of the weasel family, mustelidae, and are renowned for their tenacity and elusiveness.
Wolverines are making a comeback in Washington’s Cascades, but with shrinking spring snowpacks and a shifting climate, their future remains uncertain. These alpine icons are in need of protection!
Through the courts and our work with state and federal agencies, we’re supporting Endangered Species Act protections for wolverines.
We also conduct field research on wolverine recovery in Washington, including through our Community Wildlife Monitoring Project and the Cascades Wolverine Project, a partner effort we help administer.
And we work to protect and restore wolverine habitat on national forests and other wildlands through our Forest Field Program.

News on wolverines

We’re standing strong for Wolverines

Even with less than 300 wolverines in the contiguous U.S. and a direct threat from climate change, in August 2014 the U.S. Fish and Wildlife Service overruled advice from its own biologists and abandoned proposed Endangered Species Act (ESA) protections for wolverines.

That’s why we joined an Intent to Sue letter along with Earthjustice and other concerned organizations to ensure the agency follows well-established science and gives wolverines protections vital to their survival in the lower 48 states. We first filed a petition for a wolverine ESA listing in 2000, and have been seeking protections ever since.

Like mountain caribou, wolverines are survivors of an ice-age environment. They are threatened not only by habitat loss but by climate change, trapping, highways and other development.

A wolverine documented by our remote cameras near Stevens Pass, Washington. Photo: CNW / CWMP
“If wolverines have a strategy it’s this: Go hard, and high and steep and never back down. Not even from the biggest grizzly and least of all from the mountain. Climb everything…. Eat everybody. Alive, dead, long dead, moose, mouse, fox, frog, it’s still warm heart or frozen bones. ~ Doug Chadwick, The Wolverine Way

An elusive Washington native

Washington state has experienced a flurry of wolverine activity in recent years; sightings have been reported from Mount Baker to Mount Adams. Estimates are there are around three dozen wolverines living in Washington today, most of them in the North Cascades between I-90 and the Canadian border. 

Wolverines have also been documented near Chinook Pass, Goat Rocks and Mount Adams in Washington’s South Cascades, and in the Selkirk Mountains of northeast Washington. A pair of wolverines have also been documented in recent years in the Wallowa Mountains of northeast Oregon.

Conservation Northwest’s Community Wildlife Monitoring Project has documented numerous wolverines in the Cascades using unique chest markings and DNA from hair snags. From 2006 to 2013, researchers from WDFW and USFWS captured ten wolverines (seven female, four male) and fitted seven with satellite collars in an effort to locate natal dens and gather data on movements. The wolverines moved extensively, established large home ranges and some made long-distance dispersal movements.

Where wolverines live

Wolverines were probably never very numerous, but following years of heavy trapping and indiscriminate poison-baiting aimed at other carnivores, they were lost from most of their U.S. historical range by the early 1900s. Today, they are thought to number just 300 in the lower 48 states.

Outside of Canada and Alaska, wolverines are now constrained to remote wilderness regions in the northern and western mountainous states, in areas like the Cascade Mountains and Rocky Mountains, where heavy snowpacks persist well into spring. Most wolverines in the lower 48 states today live in Washington, northern Idaho and Montana.

Wolverines are fierce, long-distance hunters and scavengers, covering great distances in their search for carrion, including winter-killed deer, elk and mountain goats. Shy of humans, their wide-ranging travel also makes it difficult for biologists to study them. Our community-run remote cameras have captured remarkable photos of wolverines.

Wolverine facts

  • Female wolverines rely on deep snow for their dens, digging eight or more feet into the snow to provide warmth and shelter for kits.
  • Wolverines have thick, dark-brown fur with honey-brown stripes traveling along each side from the shoulders to the base of the tail. One of the early indigenous names for them translates to “skunk bear”.
  • The largest land-based animal of the weasel family, the wolverine weighs 15 to 40 pounds (larger mustelids are the sea otter and giant otter).
  • These awesome predators have a keen sense of smell for finding food—they can detect mountain goats killed by an avalanche, buried deep beneath the snow.
  • Wolverines are predominantly scavengers of carrion of large mammals, including mountain goat, deer, elk, moose, and caribou. But they also prey on marmots, ground squirrels, snowshoe hares and other small mammals. Like coyotes and other carnivores, they will also eat insects and berries.
  • Wolverines are capable of taking down animals five times their own body weight when snow conditions give them a predatory advantage. They are known to chase away cougars and grizzly bears!
  • Wolverines are most often solitary, except during mating season. But as we learn more about them, we see that they will occasionally hunt together, and sometimes “hang” with siblings.