Wolverine (Guio gulo) adult on a frozen river during winter in the Rocky Mountains of Montana; captive animal (by Daniel J Cox/NaturalExposure.com).

Lawsuit Filed to Protect Imperiled Wolverine

December 14, 2020

Nick Cady, Cascadia Wildlands, 314-482-3746, nick@cascwild.org
Matthew Bishop, Western Environmental Law Center, 406-422-9866, bishop@westernlaw.org 

Coalition lawsuit: Science says wolverines need protection

Today, a coalition of wildlife advocates challenged the Trump Fish and Wildlife Service’s (the Service’s) decision to deny protections to imperiled wolverines under the Endangered Species Act. This is the second time the Service has prioritized politics over science for wolverines, which number about 300 in the contiguous U.S.

The groups in today’s filing defeated the Service in court in 2016, forcing the agency back to the drawing board with a directive to apply the best science. Four years later, the Service has returned with the same decision to deny wolverine protective status, despite no new scientific support for such a determination.

“This is yet another chapter in this administration’s war on science,” said Matthew Bishop, an attorney with the Western Environmental Law Center. “Public records reveal the Service decided not to protect wolverine from day one and then worked backwards to figure out how to make the decision stick. It’s really unfortunate.”

In April 2016, a federal judge sided with conservation groups, agreeing that the Service’s August 2014 decision not to list wolverine as threatened was arbitrary and contrary to the scientific literature. The court held: “[T]he Service’s decision against listing the wolverine as threatened under the ESA is arbitrary and capricious.

“No greater level of certainty is needed to see the writing on the wall for this snow-dependent species standing squarely in the path of global climate change. It has taken us twenty years to get to this point. It is the [court’s] view that if there is one thing required of the Service under the ESA, it is to take action at the earliest possible, defensible point in time to protect against the loss of biodiversity within our reach as a nation. For the wolverine, that time is now (Opinion at page 83).”

The court also noted clear evidence of political interference in the Service’s reversal. “Why did the Service make the decision [to not list the wolverine]?…Based on the record, the Court suspects that a possible answer to this question can be found in the immense political pressure that was brought to bear on this issue, particularly by a handful of western states (Opinion at page 56).”

Before its decisions to deny wolverines endangered species protections, the Service identified climate change, in conjunction with small population size, as the primary threat to the species’ existence in the contiguous U.S.

The wolverine relies on snow year-round. With its large paws, it can travel easily over snow, and often relies on deep snow for hunting. Snow is also a “freezer” that permits the wolverine to store and scavenge food. One study found 98% of all wolverine den sites in places with persistent snowpack.

Published, peer-reviewed research, the independent Society for Conservation Biology, the majority of experts who reviewed the decision, and the Service’s own biologists all verified this finding.

The Service proposed listing the wolverine as a “threatened” species under the ESA in 2013. At the eleventh hour, however, the Service reversed course and chose not to protect wolverine, citing too many “uncertainties” in the scientific literature. This dubious about-face led the court to reverse the decision.

Today’s complaint aims to ensure the Service utilizes the best available science when making listing decisions, and provide wolverines the protective status they desperately need and deserve.

“This is something we were really hoping to avoid after the court’s 2016 decision,” said Bishop. “I was cautiously optimistic the Service would get it right this time and we’d be focusing our time and energy on developing a conservation strategy, recovery plan, critical habitat, and possibly reintroduction efforts for wolverine. Instead, we’re back in court challenging an agency that continues to put politics over science.”

The groups on today’s complaint include WildEarth Guardians, Friends Of The Bitterroot, Friends Of The Wild Swan, Swan View Coalition, Oregon Wild, Cascadia Wildlands, Alliance For The Wild Rockies, Cottonwood Environmental Law Center, George Wuerthner, Footloose Montana, Native Ecosystems Council, Wildlands Network, Helena Hunters and Anglers Association.


Wolverine number just 250-300 individuals in the contiguous U.S. and are dependent on high elevation habitat with deep winter snows. Imperiled by climate change, habitat loss, small population size and trapping, wolverine were first petitioned for Endangered Species Act protections in 2000. The Service found the petition did not contain adequate information to justify a listing. A federal court overturned that decision in 2006. The Service then issued a negative 12-month finding in 2008, which was challenged in court resulting in a settlement that led to a new finding that wolverine should be protected under the ESA, but that other priorities precluded the listing at that time. A landmark settlement, which resolved the backlog of imperiled species awaiting protections, then guaranteed a new finding for wolverine. In February 2013, the Service proposed listing the wolverine as “threatened” under the ESA. In August 2014, however, the Service reversed course and issued a decision not to list the species, contradicting its own expert scientists’ recommendations. In April, 2016 the court overturned the Service’s decision not to list, reinstating wolverine’s status as a candidate species and requiring a new final rule. Today’s decision is the result.