09/22/2026
When we kill cougars, we break the balance.
Cougars in Oregon's Blue Mountains kill nearly a quarter of the local coyote population every year. The coyotes keep coming back because the same animal killing them is also feeding them. A four-year study published in the Proceedings of the National Academy of Sciences found that coyotes in this landscape depend so heavily on scavenging cougar kills that their diets nearly match the cougar's own, and the price of that free food is a mortality rate that would collapse the population if new coyotes were not constantly replacing the dead ones.
Joel Ruprecht, Taal Levi, and Charlotte Eriksson at Oregon State University ran the study between 2016 and 2020 at the Starkey Experimental Forest and Range in northeastern Oregon. They collared 17 cougars, 17 coyotes, 11 black bears, and six bobcats with GPS units that recorded each animal's position every two to three hours.
They collected more than 2,000 s**t samples to determine what each species was eating. They investigated 128 confirmed cougar kill sites on foot and deployed trail cameras at 28 of them to document which animals visited the carcasses and what happened when they did.
The cameras told a story that GPS coordinates alone could not. Coyotes showed up at cougar kill sites repeatedly and predictably. The attraction was so strong that the researchers described it as an overwhelming determinant of coyote behavior, space use, and resource acquisition. Elk appeared in coyote s**t at rates that nearly matched the cougar's own diet, and since coyotes in the Blue Mountains rarely kill adult elk or even elk calves on their own, virtually all of that elk consumption came from scavenging cougar kills.
The cougars were, effectively, feeding the coyotes.
They were also killing them. When the researchers factored in the density of both species across the study area, the data indicated that cougars were responsible for killing nearly one-quarter of the local coyote population annually.
The finding carried an additional detail that made the relationship harder to categorize: in many cases, the coyotes were not killed while scavenging. Cougars were killing coyotes away from kill sites too, suggesting the mortality was not simply a cost of approaching a carcass too closely. The cougar was treating the coyote as a competitor worth eliminating regardless of whether food was involved.
Ruprecht described the tension directly: that kill percentage estimate implies a strong suppressive effect counteracting the benefit to coyotes provided by the cougars. Overall, the issue of whether subordinate species incur a net fitness cost or benefit from dominant predators is far from resolved.
One trail camera clip captured the dynamic in a few seconds of footage: a cougar chasing three coyotes away from an elk carcass it had killed, the coyotes' alarm calls audible in the background as they s**ttered into the trees. They would be back. The cougar would still be there.
Levi framed the management implication with the bluntness the data required. If you hate cougars, you might say we have to kill them because not only are they killing deer but they are supporting an abundant coyote population that also kills deer. Or you could say we need to keep cougars because they are diverting coyotes away from deer by supplying them with elk. Both of those are missing parts of the story that are still uncertain.
Image is for illustration purposes only
Source: Ruprecht, Eriksson, Levi, et al. (2021), Proceedings of the National Academy of Sciences / Oregon State University / National Geographic / ScienceDaily.
