An analysis of mountain lion predation upon mule deer and elk in the Idaho Primitive Area

Hornocker's pioneering radio-telemetry study of cougars in central Idaho was among the first to quantify how a solitary felid affects its ungulate prey. By tracking marked lions through winters and reconstructing kills, he estimated kill rates, prey composition and the age and condition of mule deer and elk taken. He concluded that lion predation was largely compensatory and removed vulnerable individuals rather than regulating prey numbers, and that prey were not limited by lions under the conditions studied. The work established field methods for studying cougar predation and framed the long-running debate over whether felid predation is additive or compensatory, a question central to deer and elk management across western North America.