Rare & Endangered
Wolverines in Yellowstone
Scientists search for ways to protect an animal we know very little about.
By Amy Leinbach Marquis
Since the 1990s, wildlife biologists have been chasing ghosts in Yellowstone National Park. Evidence of an elusive predator in the area had been mounting for years: snow tracks, tufts of fur on tree bark, abstract snapshots of individuals who tripped infrared beams on camera traps. This was not an animal attracted to human terrain abundant with garbage cans and livestock, like the grizzlies and wolves that cross our paths so often.
Biologists were hot on the trail of the wolverine, the largest terrestrial member of the weasel family, and one with an extraordinary devotion to wilderness. Fearing that the species would fall too far off our radar—so much that we might be threatening the population without even knowing it—scientists pressed on, determined that the more they uncovered about the species, the more they could do to protect it. But until they got their hands on a live one, their knowledge only stretched so far.
Then came March 2006, when their hard work was rewarded in the form of a young, male wolverine. A team of biologists from the National Park Service and the U.S. Forest Service (USFS) had successfully lured him in with beaver carcasses set in a cabin-shaped trap just outside Yellowstone’s northern border. A week later, another male was caught in the park near Sylvan Pass—the first individual ever to be captured inside Yellowstone. It was the big development they’d been waiting for.
“There’s so much work, resources, and logistical challenges that go into wolverine studies,” says Kerry Murphy, a wildlife biologist at Yellowstone. “It was a thrill to actually get to handle the animal and look at its physical characteristics—its big feet and its hair. And they’re tremendously strong. It’s what you’d expect for an animal that lives principally above 8,000-feet.”
The project, funded primarily by the Yellowstone Park Foundation, comes on the heels of a four-year study of wolverines in Glacier National Park. There, the team tracked movements of 20 individuals using advanced global positioning technology that records locations as often as every five minutes. The discoveries they made from this data were stunning.
“Their rate of movement is phenomenal, especially if you know anything about Glacier National Park—it’s an absolutely vertical landscape,” says Jeff Copeland, a leading USFS wildlife biologist on the team. “Wolverines will cross the park in the matter of a couple hours, a distance that would take us a couple days to negotiate. They just go over the top of mountains like you and I cross the street.”
Other surprising data showed males visiting den sites—indicating that parents may share responsibility for raising pups, a unique trait among North America’s top predators. From this and other research, biologists believe wolverine numbers hover in the hundreds throughout most of their historical habitats in the American West: Idaho, Montana, Wyoming, and the very northern part of North Cascades National Park in Washington. Their population density is extremely low—even in prime wolverine habitat, as few as six to ten individuals may occupy a 500-square mile area.
Whether or not this reflects a healthy population is hard to determine—and despite the breakthroughs in Glacier, wolverine biologists have a long road ahead. “Four years is nowhere near enough time,” Copeland says, noting that it took almost three years just for the team to get its feet on the ground and understand the logistics of tracking such an elusive animal. But because of inadequate funding, the study will likely end this year. That’s why the Yellowstone project is so important. In addition to learning how wolverines are using the park—for breeding grounds, den sites, or food sources—it’s an opportunity to get to know another group of individuals more intimately. This means figuring out population demographics, social organization, and disperal and migration patterns. Only then will biologists truly understand how this carnivore fits into the landscape, and how human activities affect that balance.
More difficult than the research itself, however, is convincing the public and policy makers that this is knowledge worth pursuing. “If we believe we are truly an intelligent species, then it’s our responsibility to recognize that our activities affect other organisms,” Copeland says.
As it becomes easier for humans to separate themselves from nature through technology and urban sprawl, perhaps the question is not how the ecological chain would suffer as a result of declining wolverine populations, but how we would suffer. It would simply be a loss, Copeland says, to never know this animal that thrives in an environment so foreign from our own, an animal that truly represents the wilderness spirit.
Amy Leinbach Marquis is assistant editor for National Parks magazine.
