Wolverine spotted on west slope of the Tetons

JACKSON — Mike Devine, 39, was out for a run Saturday morning in Darby Canyon when he spotted movement on the horizon, and thought he recognized an animal’s lanky, rolling gait.

He wasn’t sure what exactly the creature was, so he took a video, watching as it came out of Fox Creek, went into Darby Canyon, and moved very quickly across the bottom of Fossil Mountain.

When he finished his run, he sent a video around to a few wildlife guides. 

It eventually made its way to the Wyoming Game and Fish Department, where officials confirmed, though not with complete certainty, that the mammal slinkily crossing the landscape was more than likely a wolverine — a solitary carnivore rare nationwide and in the Tetons.

“I have never seen one,” said Zack Walker, the Wyoming Game and Fish Department’s non-game supervisor who this winter oversaw studies of wolverines in the state’s main mountain ranges, the Tetons included.

“I’m jealous of anybody who sees them,” he said. “I’ll just put it that way.”

Walker said he couldn’t be 100% certain that the animal Devine saw was a wolverine because of how far away the video was taken from. But based on its gait, he was “pretty sure” it was. That’s because wolverines have a distinctive rolling stride, similar to that of a ferret. Both ferrets and wolverines are mustelids, along with weasels and badgers, but wolverines are the largest member of that family.

“It almost looks like a wave,” Walker said of wolverines’ walk.

Devine, who lives in Victor, Idaho, said he suspected the animal was a wolverine Saturday, even though it was roughly a half mile away, because of its color, the length of its tail and the way it was moving.

“I was pretty sure it wasn’t a bear, and it wasn’t moving like a fox,” he said.

North American wolverine populations historically extended south to California and New Mexico, but by the 1920s the animals were almost eliminated in the lower 48 states because of unregulated harvest, habitat loss and widespread carnivore poisoning, according to Wyoming Game and Fish.

After years of legal back and forth, wolverines are proposed for listing as “threatened” under the Endangered Species Act. Wyoming considers them a “species of greatest conservation need” and manages them as a non-game species, meaning they cannot be hunted. 

Now, biologists estimate that between 300 and 400 wolverines reside in the U.S., with the Greater Yellowstone Ecosystem at the southern end of their suspected range. Because the animals are solitary creatures with large home ranges and, consequently, expensive to track, it’s hard to say how many live in the Tetons, and Wyoming as a whole.

In 1999, researchers studying wolverines in the Tetons were able to trap only three animals. In 2019, researchers studying how recreation impacted wolverines were able to trap only one male.

When Wyoming Game and Fish studied wolverine habitat between 2015 and 2017, it detected activity in the Tetons. But the department wasn’t able to say how many of the unique animals lived in the local range. It detected only six to eight unique wolverines in the Absaroka and Wind River mountains.

Game and Fish was working on updating that study this winter, Walker said, but data was still being processed and he wasn’t able to say if wolverines were detected in the Tetons. The department did find evidence of gulo gulo, another name for wolverine, northeast of Moran junction and in the Wind River Range. Walker said data from the Teton, Bighorn and Snowy Mountains has yet to be processed. The same is true for Yellowstone.

It is safe to say that wolverines are incredibly rare, he said. “Because there’s so few within the state, only a handful of people get to see them in a given year.”

Devine was thrilled to see the wolverine, pointing to its reputation for ferocity and “reputation for being really powerful, small beings.”

“They’re kind of legendary,” he said. “For such a small animal, it’s something I’ve always been a bit intimidated by.”

He’d heard that a wolverine can take out a “full-sized grizzly bear.”

Walker, for his part, said a full-size grizzly would likely “go beyond” wolverines’ capabilities. But he acknowledged that the animals are fierce little buggers, capable of preying on larger animals like elk that are mired in snow, and fending off multiple wolves. If a grizzly got in a wolverine’s way, the smaller member of the weasel family would likely rush it or bite at it, the Game and Fish biologist said.

“If it puts on a good enough show, the grizzly might back off,” Walker said.