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Species of the Pacific: The Wolverine

Two fuzzy baby birds with large eyes huddle together on a brown branch, with a green backdrop of tree leaves behind them.

This is post 3 of 4 in "Species of the Pacific."

Throughout this series, we explore the ecosystems in the Pacific Northwest and the wildlife who inhabit them, including the Northern Spotted Owl, the wolverine, and bullhead trout. Our newly launched Pacific Wildway aims to reconnect, restore and rewild the Pacific region so that these species and more can thrive. All posts in this series…

Rare and elusive, wolverines shy away from human activity. In the Lower 48, they primarily roam the high alpine reaches of the Rocky Mountains and the Cascade Range. Females dig complex tunnels with their razor-sharp claws in deep snow to protect their kits—born in February or March—from predators and harsh weather.

A wolverine standing on a talus slope looks toward the photographer
A wolverine in the Rockies. Photo: Steven Gnam

Successful maternal denning is reliant on snow that lingers into late May, which provides females the security to wean their young. Because of the wolverine’s dependence on persistent spring snow, some scientists are concerned that rising global temperatures may threaten the survival of this species. Wolverines have only recently returned to the Cascades after being extirpated from the region by the 1930s.

Although some people think wolverines (Gulo gulo) resemble small bears, with their deep brown to blackish fur, they are actually the largest terrestrial members of the Mustelid (weasel) family. Adult wolverines typically weigh less than 40 pounds and are considered fierce and territorial. They are highly adapted to snow, with paws like built-in snowshoes and claws that can dig into ice.

Wolverines have a keen sense of smell and are excellent at finding carrion left behind by larger animals or killed by avalanches. They have huge home ranges and can disperse long distances. “Buddy,” the wolverine documented in Tahoe, California, may have traveled more than 600 miles from the Northern Rockies before settling into his new home.

The Plight of the Wolverine

Wolverines, once considered extinct from Washington, are slowly making a comeback. In the early 1990s, mountaineers reported wolverine tracks in the North Cascades, and camera traps soon began to confirm their presence. Since that time, there have been sightings recorded as far south as Mount Adams in southern Washington, although most of the state’s wolverines still reside in the North Cascades between Interstate 90 and British Columbia.

Closeup of a wolverine in the snow, showing large feet with long white claws.
A wolverine has large feet suited for traveling huge distances on snow. Photo: Steven Gnam

With only 300 wolverines estimated to remain in the Lower 48, this iconic species is in danger of losing its already-tenuous foothold. Federal agencies have continually dismissed the wolverines’ perilous status here.

In 2014, the U.S. Fish and Wildlife Service withdrew a proposal to list the wolverine as a threatened species under the Endangered Species Act, claiming that threats of a warming climate and reduced snow pack were not sufficient to meet ESA standards. Several conservation groups, including Wildlands Network, successfully challenged this finding in the courts. In 2016, the federal district court for Montana rejected the USFWS’s decision to deny protections for wolverines in the contiguous U.S., and the agency must now make a new final listing determination for wolverines. But climate change does not wait, and the wolverine’s very existence is at stake.

Did you know? The track in our logo emblemizes the mystery and movement of wolverines, who must travel huge distances to meet their life requirements.

Wildlands Network recently worked with the Endangered Species Coalition on a report titled,  “Suppressed: How Politics Drowned out Science for Ten Endangered Species.” The report highlights 10 imperiled fish, plant, and wildlife conservation decisions in which science was either ignored or suppressed as result of special interest lobbying and influence.  Wildlands Network nominated the wolverine for inclusion in the report because the USFWS withdrew the proposal to list this species as threatened.

Climate change has put wolverines in a dangerous position. The warming climate may be directly impacting the wolverine’s suitable habitat by reducing glacier size and shrinking spring snow pack; wolverines may find it challenging to adapt to our shifting landscape. Here at Wildlands Network, we are hoping to change the potentially ill-fated course of the wolverine’s future and help this species expand its range into the South Cascades, Oregon, and California.

Rewilding the Pacific for the Wolverine

Currently, wolverines in the Pacific Northwest are primarily found in the Northern Cascades of Washington. Because of their tendency to avoid human disturbance, maintaining habitat connectivity in remote alpine and forested environments is key to their long-term survival.

A bear-like animal with light brown and dark brown fur climbs a tree toward a bait bone, with snow on ground.
A wolverine visits a camera-trap station in the North Cascades of Washington. Photo: Woodland Park Zoo

Our Pacific Wildway project will map and analyze climate corridors throughout the Pacific Northwest and into California, hopefully shepherding climate-change-vulnerable species like the wolverine to areas that remain suitable for them. We’ll work with conservation partners to identify, restore, and rewild key habitat areas for wolverines. 

In coordination with our conservation partners, we will also continue to hold the USFWS accountable to their mission to “work with others to conserve, protect, and enhance fish, wildlife, plants and their habitat for the continuing benefit of the American People.” We will continue to fight for enhanced protection for wolverines and other species at clear risk of habitat loss due to our rapidly changing climate. The wolverine’s future in the Pacific Northwest is at stake if we don’t act now.

To support these critical efforts and help expand our Pacific Wildway, please consider donating to Wildlands Network.

Correction: An earlier version of this blog post misstated the effects of climate change on wolverines.

More posts from Species of the Pacific

  1. Exploring Ecosystems of the Pacific Northwest, March 16, 2018
  2. Species of the Pacific: The Northern Spotted Owl, March 19, 2018
  3. Species of the Pacific: The Wolverine, March 22, 2018
  4. Species of the Pacific: Bull Trout, April 5, 2018

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