The Service's recommendation not to list wolverines dealt almost entirely with the question of whether there was an adequate basis for listing due to uncertainty about climate change and failed to address all of the other multiple threats to this highly imperiled species.

The wolverine is threatened by the species' small population size, low genetic diversity, and direct or indirect impacts from trapping, winter recreation, and habitat destruction. These threats are made worse by loss of snowpack across much of the West habitat needed for this snow-dependent species. The wolverine is in dire need of federal protection.

There are only 250-300 animals left in the lower-48 states. Shockingly, the Service has concluded that the wolverine population is increasing, but there is no published research to show this is occurring. What we do know is that the "effective population" the number of wolverines who contribute annually to the production of future generations, and a common measure of a population's genetic health is estimated at 35 individuals; shockingly low by any conservation standard. Wolverines live a tenuous lifestyle and they have one of the lowest successful reproductive rates known to mammals. The bottom line: this is a highly vulnerable population and any threat must be taken seriously.

Defenders intends to continue to fight to list this species under the ESA.


Over a decade ago Defenders and our conservation partners filed the original petition to list these animals under the ESA, and none of the threats we outlined then have disappeared. Indeed, many are even more pressing today.

What would federal protections provide? Listing wolverines as "threatened" would put a ban on wolverine trapping particularly important in Montana where the state still allows a wolverine trapping season. Federal protections would also help reduce other threats to the wolverine and help wolverines reestablish in habitats they once occupied prior to their near-extermination in the 1900s. Places like Colorado's Southern Rockies and California's Sierra Nevada have ample suitable habitat with predicted sufficient snowpack in the future for these snow-dependent animals, but currently they have no wolverine populations.

The Service made the wrong call today and in doing so jeopardized the potential survival of this elusive species.