Male and Female Wolverines Documented in the Wind River Range for First Time in More Than 100 Years
The short video starts like most wildlife trail cameras. A creature leaps up the base of a tree from the snow and scurries around its trunk. It’s trying to eat pieces of a dead deer hung by biologists as part of a survey.
But in the next short clip, the wolverine disappears.
When it reappears, the viewer sees only nose as the wolverine sniffs and plays with the camera. Then the fierce animal, memorialized in comics and folklore, adjusts the trail camera to capture his final act.
It climbs back up the tree, spends a few more minutes eating, and then curls up in a ball and rolls down the snowy hill and out of the frame.
“We like to anthropomorphize, and we do it for fun, but it’s pretty funny to think of what he did,” said Pat Hnilicka, project leader of the U.S. Fish and Wildlife Conservation Office in Lander. “They are an animal that by nature are highly curious. They are designed to find food in unusual places deep under snow.”
Aside from entertaining – the video had been viewed thousands of times – it shows something more important: Wolverines are continuing to expand south.
For the first time in more than a century, males were documented in the Owl Creek Mountains on the Wind River Reservation, and both males and females were found in the northern and southern ends of the Wind River Range. That means for the first time in more than a century, the Wind Rivers likely have breeding pairs of wolverines.
“It was pretty great to know that there is possible breeding occurring in the Wind Rivers. I think everyone was really excited,” said Zack Walker, nongame program supervisor with the Wyoming Game and Fish Department. “We see ourselves as the southern edge of recolonization.”
Even at their most populous, wolverines never occurred in very large numbers. They’re solitary, territorial and reproduce at an extremely slow rate. One female will likely have two cubs every two or three years.
But by the early 1900s, all information suggested the badger-like species was wiped out from the lower 48. They were trapped or poisoned as the West was developed, leaving Canada and Alaska as the remaining wolverine strongholds in North America.
In the 1930s, they started slowly moving back down. The blue-heeler-sized mammal is known for epic explorations – one notable male went from the Teton Range to Rocky Mountain National Park in Colorado and back up to North Dakota where it was shot by a ranch hand. But species expansion requires more than lone males on walkabouts, it needs females.
For years, the only wolverines documented breeding in Wyoming were in the Tetons.
That’s why news of males and females in the Wind River Range is so important, said Bob Inman, carnivore and furbearer coordinator for the state of Montana and arguably one of the country’s foremost wolverine biologists.
“It looks like good habitat but we just didn’t know if they were there or not. It was satisfying to find that it’s occupied at least by a few wolverines, and the same with the Gros Ventre Range,” he said. “Both of those are exciting because they are as far south as we know of wolverines breeding and males and females occurring. It’s fair to assume if there are males around and females around they are going to find each other.”
The news of expansion – and cheeky video – came late this winter at the end of a massive undertaking by the Wyoming Game and Fish Department, U.S. Fish and Wildlife Service, several other states, the U.S. Forest Service and multiple tribes. For three winters, the agencies and a handful of volunteers worked on one of the largest wolverine surveying efforts ever conducted in the West.Wolverines are notoriously hard to track because of their solitary nature and their homes in high, harsh mountain climates. They can’t be counted from the air like elk or bighorn sheep, and they don’t run in packs like wolves.
Plotting where they are across a four-state region is even trickier. Officials first identified suitable wolverine habitat – largely high, snow-covered mountain tops – and then divided those into 15-by 15-kilometer quadrants.
Within those quadrants, biologists like Walker, Inmnan and Hnilicka looked for good places for trail cameras and wire brushes to collect DNA.
Biologists then skied into the camera traps set at 8,500 or 10,000 feet every month from December to March to check the cameras and replace scent and bait.
Inman has tried trapping wolverines in the past. One winter he caught five total and considered it a success.
He and the others decided setting up camera traps with dead beaver or deer as bait would save on manpower and offer more specific data on population and distribution.
The study was not intended to figure out population – Inman isn’t sure they could ever extrapolate an exact population estimate.
While he and the others are satisfied knowing wolverines are distributing farther south, where they go from here is less clear.
Colorado has plenty of good wolverine habitat, as does Utah. But those females in the Wind Rivers would need to cross endless expanses of prairie and desert to get there. While lone males may do it, he isn’t sure if females will traipse across places like the Red Desert.
Inman believes reintroducing wolverines into the high mountains of Colorado or California could be the answer, but it comes with political concerns around a possible Endangered Species Act listing and potential impacts on land use.
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Photo by Mark Packila