WC can count on one hand, with digits left over, the number of times he has seen a wolverine in the wild. Once along Sunset Creek in Denali National Park in a drenching rainstorm; once along the Delta River, below the falls; and once backpacking along the Marsh Fork in the Brooks Range. Unmistakeable, that humping run and low, dark shape. If there is a creature that embodies true wilderness, it’s the wolverine.
The species is exceptionally well adapted to its habitat. Oversize feet allow it to move in deep snow. A fur coat which repels water and frost. And it’s thermoneutral – meaning it doesn’t have to make additional energy expenditures to keep warm – down to -40°F. And strong: Scientists have tracked a radio-collared wolverine as it travelled 11 kilometers and climbed 2,000 feet in deep snow in just four hours. The wolverine is also a creature of legend; Ulo ulo is surrounded by a mist of legend, superstition, idolatry, fear, and hatred.
And it’s that mythos that helped trigger the near-hysterical reaction in Western states when the Fish & Wildlife Service proposed to classify the wolverine as endangered.
Wolverines require deep snow. Wolverines requires snow in order to reproduce. Scientists have posited a number of explanations for this relationship – thermal protection and/or predator shielding for newborn kits, food caching. Regardless of the reason, there is consensus that the relationship is obligate at the den scale. In Idaho, for example, denning sites occur above 8,200 feet, often in north-facing boulder talus fields or subalpine glacial cirques in forest openings. No wolverine has ever been observed denning anywhere but in snow.
Anthropogenic climate change is making those deep, long-lasting snowdrifts vanish. Like the polar bear, the CO2 and other greenhouse gases mankind is pumping into the atmosphere is endangering the wolverine. The U.S. Fish & Wildlife Service proposed classifying the species as endangered across its range. The determination was based in significant part on global climate models. Use of those models, you will recall, were approved in the polar bear decision. But the proposed wolverine determination provoked a firestorm of criticism from the Western states. The Fish & Wildlife Service lost is nerve and withdrew the proposed rule.
Defenders of Wildlife, reasonably enough, thought that was politics and not science, and challenged the withdrawal of the proposed classification in Defenders of Wildlife v. Jewell. And won. U.S. District Chief Judge Dana Christensen, in a long and detailed opinion, concluded the decision against listing the wolverine as threatened under the ESA was arbitrary and capricious. He found, “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.” Put another way, the Endangered Species Act requires use of best possible science. It is error to insist on still better science and decline to act when the best possible science supports classification as an endangered species.
Doubtlessly, the Western states who intervened in the case will appeal. But the Ninth Circuit has already reached very similar conclusions regarding polar bears and wolverines, a deep snow-dependent species, are very much an indicator species on land as the polar bears are on sea ice. A reversal at the court of appeals appears unlikely.
We live in times in which the Endangered Species Act itself may be endangered. And a wolverine recovery plan is impossibly handicapped by the inability of USF&WS to directly limit global warming. So it could be a hollow victory. But it’s still a victory for the little bear and the rule of law over politics.