Where wolverines roam

Wolverines have long been shrouded in mystery. They live solitary lives at high elevations in country so remote that even those who study the animal rarely see more of them than tracks in the snow. Wolverines are so elusive that fundamental questions such as where they live and how many exist have remained unanswered.

Last winter, Wyoming wrapped up field efforts for a two-year, multi-state wolverine study that is trying to change that.

Wyoming Game and Fish Department biologists photographed several wolverines last winter and know at least three were unique. DNA analysis from hair gathered at the sites will tell whether there were more than three, or if some were photographed more than once, said Lee Tafelmeyer, a wolverine project biologist with WGFD.

The department, with the help of citizen scientists, baited 26 sites to lure wolverines in front of a camera last winter. It was the last field season of a two-year study.

Wolverines were caught on camera at sites along tributaries of the North Fork of the Shoshone River in the Shoshone National Forest and on the Bridger-Teton National Forest, Tafelmeyer said. Researchers also found tracks, which led them to wolverine hair northeast of Jackson. Last winter three wolverines were detected at different sites.

While there has been wolverine research in specific areas in Wyoming, like the Tetons, this is the first study to look at statewide distribution of wolverines, Tafelmeyer said.

Wyoming is running its own study, but will share data with Montana, Idaho and Washington to give a sense of the population across the region. The goal is to establish a baseline distribution-and-occupancy map of wolverines the lower 48 states.

Right now there isn’t a way to tell if the wolverine population is declining, stable or on the rise, because there isn’t baseline data, said Zack Walker, statewide WGFD nongame bird and mammal program supervisor.

With the data from this study, if wildlife managers notice the population decreasing, they can consider ways to help the animals thrive. The data from studies like this can help wildlife managers keep animals from reaching population levels that warrant endangered species protection, he said.

In 2013, the U.S. Fish and Wildlife Service proposed designating wolverines as a “threatened species” under the Endangered Species Act, due to projected habitat loss from increased snow melt. The agency reversed its decision in 2014. In 2016, a federal district court judge in Montana sided with the environmental groups that challenged the reversal and invalidated the withdrawal of the proposed listing. A decision on listing the wolverine is now pending.

Researchers believed wolverines to be extinct in Wyoming only a few decades ago. The stocky badger-like animals were illegally trapped and, researchers believe, fell victim to poisons targeting wolves. Wolverines give birth to only one or two young every few years so the population is slow to rebound, Walker said.

Working with other states is particularly helpful with animals like wolverines, Tafelmeyer said. The animals are incredibly hard to find and therefore to study. Wolverines often live at 8,000 feet and higher. They lead a solitary existence and only one or two might occupy a mountain range.

The sample sizes for Wyoming are almost too small to analyze, Tafelmeyer said. Having a larger data set allows for more accurate information, and gives a much broader picture of how the species occupy the lower 48 states, he said.

With the field work over, researchers are awaiting genetic analysis of hair samples, which tell the sex of the wolverines spotted and if the same one visited sites multiple times.  

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Walker said he’d like to repeat the study in about five years. With the newly acquired baseline data in hand they’d be able to  see how the population has changed and begin a long-term monitoring program, he said.

The baseline data is important, but it only begins to scratch the surface of researchers’ questions about the animals. Wolverines den in areas that keep snow into the spring — habitat that is in increasingly short supply. Researchers would like to know, for example, how, or if, the animals are adapting and changing their behavior with climate change, Walker said.

Tafelmeyer said he’d like to know how the animal’s population varies and if they are reproducing in Wyoming.

“With wolverines, it’s almost like the more you learn, the more questions you develop,” Tafelmeyer said.