Will Wolverines be Listed Under Endangered Species Act?

During his 1805 explorations into the newly acquired American West with William Clark, Meriwether Lewis encountered an animal near current-day Great Falls, Montana, that he first mistook as a small wolf and later concluded was “of the tiger kind.” Based on Lewis’ written reports, the National Park Service believes that he encountered not a wolf nor a tiger, but rather a wolverine.

The largest member of the weasel family, wolverines are reclusive animals that look more like small bears than tigers and once inhabited large swaths of North America. Now, wolverines have an estimated population in the hundreds across the contiguous United States and are posed to be listed as threatened under the Endangered Species Act.

The U.S. Fish and Wildlife Service first proposed listing wolverines in the Lower 48 in 2013 and following a dance of withdrawing and reinstating the proposal, the Service has once again reinstated its 2013 listing proposal per a 2022 ruling from the District Court of Montana. The Service released a Species Status Assessment in September and will submit its final determination to the Federal Register by Nov. 27.

“Overall, future wolverine populations in the contiguous U.S. may be less secure than we described in our 2018 SSA,” the 100-page assessment reports.

A loosely estimated 318 wolverines resided in the western U.S. in 2013, according to the assessment, with the highest occupancy rates found in the Northern Continental Divide region of Montana. More recent estimates have not been made since population numbers are difficult to estimate given the inaccessibility of wolverine habitats and the creatures’ highly mobile tendencies; data from collared wolverines indicates the Gulo gulo can travel hundreds of miles in a matter of mere weeks over home ranges of up to 600 square miles. The assessment does, however, reference Canadian studies that saw a 40-percent population decline in the southwestern part of the country between 2011 and 2020.

“Uncertainty over the wolverine’s future condition in the contiguous U.S. is relatively high,” the assessment concludes. “The best available information suggests that habitat loss as a result of climate change and other stressors are likely to impact the viability of wolverines in the contiguous U.S. through the remainder of this century.”

Wolverines are partial to alpine landscapes and rely heavily on subnivean space—the environment between fallen snow and terrain—for denning, thermoregulation, escaping predators and caching food, making them especially vulnerable to climate change, according to the Fish and Wildlife Service. The species also has a naturally low reproductive rate, making impacts to their habitat doubly consequential.

If the determination finds that wolverines are threatened in the contiguous U.S., species management will shift from state agencies to the federal government.

Despite varying protections under current state management in Montana, Wyoming, Idaho and Washington, wolverine harvesting is not permitted in any of these states. Montana Fish, Wildlife and Parks received a report of an illegally killed wolverine earlier this month, according to a Nov. 16 press release. The animal was shot, skinned and abandoned in Beaverhead County. At the time of publication, game wardens are still investigating the incident and have not yet identified the hunter.

Stay tuned to Mountain Journal for more in-depth reporting on wolverine protection status once the determination is made.