Official Government Website

North American Wolverine

ESA Status: Delisted and Removed from List

Populations of the North American wolverine (Gulo gulo luscas) span across the contiguous United States, Alaska, and Canada. Wolverines are known for their bushy tail and claws used for digging dens, climbing through high-elevation mountain environments, and scavenging for food. The wolverine is currently being proposed for a threatened listing under the Endangered Species Act (ESA).

In 2013, the U.S. Fish and Wildlife Service (FWS) proposed to list the North American wolverine as threatened under the ESA. The FWS pointed to climate change as the sole justification for listing the wolverine. Based on limited habitat data and climate modeling, the FWS concluded that the snow-dependent species is likely to become endangered within the foreseeable future due to increasing global temperatures, which reduces the amount of available habitat.

The state of Idaho, through the Office of Species Conservation (OSC), submitted comments in response to the Service’s proposal to list the wolverine as threatened. The comments can be read at the following link (State of Idaho Comments Regarding the Proposal to list the North American Wolverine as Threatened).

Based on feedback from the states and other interested parties, the FWS withdrew the proposal to list the North American wolverine as a threatened species in 2014. The FWS stated that the wolverine does not warrant protection under the ESA because the effects of climate change are too uncertain (i.e., climate change will not negatively affect the population within the foreseeable future).

In April 2016, the U.S. District Court of Montana vacated FWS’ final determination that the wolverine population is not currently threatened by climate change. The judge disagreed with FWS’ analysis that climate change does not pose an immediate threat and ordered wildlife officials to reinitiate the proposal to list wolverines as a threated species.

In October of 2020, FWS withdrew their 2013 proposed rule to list the distinct population segment of the North American wolverine occurring in the contiguous United States as “threatened” under the ESA, stating that the best available science shows that the factors affecting wolverine populations are not as significant as believed in 2013. FWS found that new research and analysis show that wolverine populations in the American Northwest remain stable, and individuals are moving across the Canadian border in both directions and returning to former territories, therefore concluding that the species does not meet the definition of a distinct population segment or as a threatened or endangered under the Endangered Species Act (ESA).

Idaho has a vested interest in wolverine conservation and has been proactively involved in research and conservation in the northern Rocky Mountains. OSC will continue to better understand wolverine behavior and advocate for increased local and national coordination.

Staff Contact:

Joshua Uriarte

Wolverine on log
Photo Credit: William F. Wood CC BY-SA 4.0 on Wikimedia Commons
wolverine standing on sheet of ice
Photo Credit: Daniel J. Cox, NaturalExposures.com
Map of Idaho with nearly the entire state shaded green indicates that these animals can be found year round in the majority of the state.
North American Wolverine Range
Map Credit: Idaho Department of Fish and Game
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