Though seldom seen due to their low population density and solitary behavior, wolverines do indeed live inside Yellowstone National Park. With approximately 6 to 7 individuals documented within Yellowstone’s 2.2 million acres, the chances of encountering a wolverine are vanishingly small. The mid-size carnivores are so rarely observed and inhabit such remote terrain at low densities that accurately assessing population is difficult. The last confirmed sighting was back in March 2022 when an adult was photographed crossing a road.
The following was taken by Montana wildlife photographer Trent Sizemore who captured dashcam footage of an unidentified animal running across a road outside of Yellowstone’s West Entrance while driving through a snowstorm on November 12th. While the video quality is grainy and further obscured by the falling snow, detailed characteristics of the animal’s body makeup and movements are evident that indicate he might have filmed a wolverine.
Trent describes the mystery animal as bigger than a bobcat and smaller than a mountain lion and darker in color than both. The legs of the animal were “definitely relatively short.” Wolverines are known for there loping running style that differentiate themselves from wolves and coyotes. Trent believes the animal he filmed crossed the road in a loping fashion:
Unfortunately Trent was not able to stop and look for tracks as the road was icy and he had a vehicle behind him.
“The video quality is terrible being cropped out of our dash camera clip, but I believe we saw a wolverine crossing the road this morning! What do you think? It was dark in color, had a noticeable tail, was the size of a small wolf, but much lower to the ground. It loped across the road more like a wolverine than a wolf. This was just outside of Yellowstone National Park.“ -Trent Sizemore
This is the last known footage of a Yellowstone wolverine captured on a remote trail camera outside the Mammoth Hot Springs back in December 2020:
Size and Behavior
- 38–47 inches long, 13–31 pounds.
- Opportunistic eaters. Eat burrowing rodents, birds, eggs, beavers, squirrels, marmots, mice, and vegetation (including whitebark pine nuts).
- Active year-round, intermittently throughout the day.
- Breed April to October; one litter of 2–4 young each year. Females give birth in dens excavated in snow.
- Den in deep snow, under log jams, and uprooted trees in avalanche chutes.
- Mostly solitary except when breeding.
Management Concerns
Since 2013, the wolverine has fluctuated between being listed as threatened under the Endangered Species Act (ESA) to having no federal protections. A series of court cases over the last decade have resulted in restoration of ESA threatened status in 2022, with a review status under way to finalize listing. Climate change and habitat fragmentation are chief threats to this species.
On March 5, 2022, a wolverine was photographed by a park visitor along the Northeast Entrance Road corridor. In recent years, NPS staff have documented some individual wolverines through tracks and remote camera footage obtained from other wildlife monitoring programs.