In 2017, the Washington Department of Fish and Wildlife (WDFW) started a Predator-Prey project designed “to investigate the effects of wolves and their competitors on ungulate populations in managed landscapes.” The ongoing project is studying the impact on ungulates like mule deer, whitetail deer, and elk from wolves that have colonized areas where they live. Recent findings show that wolves are being killed by cougars at a higher rate than anyone previously expected.
The project employs radio collars to monitor the movements of wolves and cougars, along with other smaller carnivores such as bobcats and coyotes. A mortality signal is sent out to biologists when collared animals stop moving for a period of time. In November, a biologist responding to a mortality signal found a wolf with deep puncture wounds on its skull consistent with the 400-pound-per-square-inch bite force of an adult mountain lion.
The dead wolf was a member of the Grouse Flats pack, which inhabits territory that straddles Washington’s border with northeast Oregon. It was located by biologists with the Oregon Department of Fish and Wildlife and made public by the WDFW in its monthly wolf report.
Little else is known about the recent cougar encounter that killed the Grouse Flats wolf, but the WDFW said it’s part of a growing trend of lions taking out wolves in Washington. “People often talk about wolves being at the top of the food chain when it comes to carnivores, or that they are ‘apex’ predators,” the agency wrote in a blog post about another Washington wolf that was killed by a cougar last summer. “Although that is accurate in some cases, in Washington, we are seeing a phenomenon that has been relatively uncommon in other states.”
The November incident marks the fifth documented case of a cougar killing a wolf from a Washington-based pack since 2013. That’s more than any other Rocky Mountain state with well-studied wolf populations has reported in twice as much time, the WDFW said. In September 2022, a Washington cougar killed a collared wolf pup at a moose kill site. And WDFW biologists suspect that other instances of cougars killing un-collared wolves have gone unreported in recent years.
WDFW biologist Trent Roussin located the dead wolf that was killed by a cougar in Washington state last summer. “From all the signs at the site, it appears the wolf was attacked while traveling down an old overgrown logging road,” Roussin wrote in a department report. “The fight ended about 100 yards downhill.”
The ambush-style attack is typical of how cougars stalk and kill all manner of prey. According to the WDFW, the stealthy, solo approach gives the big cats a substantial leg up over their pack-oriented canine competitors. “In most interactions between them, cougars are not so much hunting wolves as competing with them for food,” the agency wrote. “As in the case where the collared wolf appears to have been surprised on a logging road, cougars are known for striking in areas where slopes, trees, boulders, or other cover gives them an advantage.”
As Washington’s wolves and cougars continue to compete for food and resources, conflict between the two apex predator species is likely to continue—and may become even more pronounced. WDFW biologists say they will continue to monitor populations while gleaning whatever knowledge they can from the rising number of cougar-killed wolves in the Evergreen State.
“We’re still learning what impact [this has] and how wolves interact with other species,” the agency explained. “The hope is that what we learn from this five-year study will help not only inform decisions that are made on how to best manage each of these species in Washington, but also give us more insight into interactions that have been rare until now such as cougar attacks on wolves.”