Wolverines are now protected as a threatened species in the Lower 48 under the federal Endangered Species Act, bringing an extensive legal dispute to a close.
The U.S. Fish and Wildlife Service on Wednesday announced that the mammal will be protected under federal law and be the subject of recovery effort plans under the ESA.
Wolverines are the largest mammal in the weasel family. They are among the rarest mammals in North America, and scientists estimate fewer than 300 wolverines remain in the Lower 48, according to the USFWS.
The species once roamed lands as far south as the Sierra Nevada range in southern California. Decades of trapping and habitat loss caused numbers to dwindle to five states: Washington, Idaho, Montana, Wyoming and Oregon, according to scientists.
In Washington and Idaho, the solitary mammals inhabit rocky, snowy alpine and subalpine terrain, typically at elevations above 5,000 feet. The mammals rely on areas with deep snow intact through the late spring. Pregnant females dig dens into the snowpack to birth and raise their young.
"It's a harsh, cold, steep, rugged area they live in," said Jeff Lewis, a meso carnivore conservation biologist with the Washington State Department of Fish and Wildlife. "They have unique adaptations to be able to exploit an existence up there. They're just a remarkable critter for being able to do it."
The USFWS attempted to protect wolverines under the Endangered Species Act in 2020 during Donald Trump's presidency, but the federal agency ultimately reversed its attempt.
Lewis said the federal government's decision to protect wolverines was spurred by climate change. Washington DFW is concerned about the impacts of climate change on wolverines, lynxes and many other species that inhabit the West.
"The threat is that there could be a loss of a fragmentation of the remaining habitat that would cause a decline in the population," Lewis said in a phone interview. "It's a substantial threat that we deal with every day as we work to recover and protect species at risk. In the recovery plan, USFWS will outline measures to sustain the population and perhaps improve conditions for the existing population."
In Washington, a resident population of wolverines inhabits the Cascade Range of mountains, from the Canadian border south to Mount Adams. Scientists don't know how many of the species reside in the state.
"We believe there are more wolverines that occupy the North — north of I-90," Lewis said. "It's a bigger area. It's got more wolverine habitat. But there's a small number that reside in the South Cascades, too."
One wolverine, dubbed a "wandering soul" by Lewis, has been known to inhabit the Blue Mountains of Oregon. It's possible that the animal has wandered north into central or eastern Washington. Scientists have also detected wolverines in the Selkirk Range of mountains in northeast Washington.
"Occasionally we think wolverines wander through there," Lewis said. "That is close to resident populations, but we're not aware of a resident population in the Selkirks."
In Idaho, scientists have detected wolverines at the top of the state's panhandle in the Selkirk Mountains, as well as in the Sawtooth Range in the center of the state.
Wolverines are carnivorous scavengers and typically feed on small and medium-sized animals including voles, squirrels, rabbits and birds. Wolverines have been known to kill and feast on large game such as moose and caribou, but this occurs rarely.
The mammal's scientific name is a nod to its big appetite: Gulo gulo, meaning "glutton" in Latin.
The Idaho Governor's Office of Species Conservation disagreed with the federal government's decision to list wolverines as a protected species, according to policy advisor Joshua Uriarte.
"Contrary to the Service's decision, wolverines in Idaho and adjacent western states are a conservation success story involving interagency and interstate cooperation over several recent decades," Uriarte wrote in an email. " Wolverines have naturally recolonized most, if not all, of their historically occupied habitat in Idaho, which is primarily on higher elevation national forest lands, where human activity is limited."
Uriarte added that the state of Idaho currently monitors wolverine population and works to conserve the species and its habitats.
In recent years, Lewis said increased numbers of humans recreating in remote mountain terrain means humans are more likely to disrupt wolverine habitat.
On the rare chance humans encounter a wolverine in the wild, scientists ask that they keep their distance and avoid disturbing the animal. Seeing a wolverine in the wild is not an easy thing to do, Lewis said.
"It's a bucket-lister thing," he said. "If you go to Glacier National Park, people have seen them there."
It usually takes the USFWS quite a bit of time to put a species recovery plan together, said Andrea Zaccardi, a conservation lawyer with the Center for Biological Diversity. One change is that when the U.S. Forest Service or Bureau of Land Management is doing a project that might impact wolverine habitat — such as logging or mining — they will have to consult the USFWS and get the project cleared before beginning. The USFWS will sometimes make recommendations or sometimes even make requirements to change the project to mitigate the impact on wolverines, Zaccardi added.
Zaccardi said she is concerned with the protection exemption for wolverines that are injured or killed incidentally in the process of lawful trapping of other species.
"Trapping hasn't been a huge primary threat to wolverines in a while," Zaccardi said. "But with the expansion of baiting, trapping and snaring of wolves in Idaho, I think that could become more of an issue."
