NEWS
Cattle make up most of California wolves’ diet, UC Davis study finds
Jeffrey MeehanReno Gazette Journal
July 30, 2026, 10:19 a.m. PT
Gray wolves in northeastern California are relying heavily on cattle as a food
Researchers analyzed wolf scat collected during the summers of 2022 and 2023 from the Lassen and Harvey wolf packs, whose ranges include parts of Lassen, Plumas and Shasta counties. They found cattle DNA in 72% of the samples
“Whether it’s through scavenging or whether it’s through depredation, it’s a huge component of the wolves’ diet,” said Tina Saitone, a professor of Cooperative Extension in the UC Davis Agricultural and Reservation success is because of livestock producers in the state.”
Wolf conflicts have continued to rise in northeastern California. State wildlife officials investigated 267 suspected wolf-livestock depredations in 2025, up from 74 in 2024. Of the 2025 investigations, 198 were confirmed or probable losses caused by wolves. During the first quarter of 2026, investigators examined another 47 reports, confirming 21 livestock losses and classifying six others as probable wolf attacks
Gray wolf population continues to expand
Gray wolves naturally returned to California in 2011 after being absent for nearly a century. By the end of 2025, the state’s population had grown to a minimum of 55 wolves living in nine packs
The state has since identified 12 known resident wolf pack territories, with most located near the Nevada and Oregon borders
Researchers said wolves in northeastern California have fewer wild prey options than wolves in many other parts of North America. Mule deer are a significant wild foodnce the 1970s
Gray wolves are protected under the federal Endangered Species Act, making it illegal to kill them, even when they are killing livestock. Violations can carry penalties of up to one year in jail and a $100,000 fine
A second UC Davis study found cattle living near wolves had cortisol levels 58% higher than herds without wolves. Cortisol is a hormone that accumulates in hair over time, allowing researchers to measure long-term physiological stress. Researchers said more study is needed to determine whether the elevated stress affects reproduction rates
