Overview
- Two UC Davis‑led studies published July 8–9 found cattle DNA in 72% of wolf scat samples from two northeastern California packs and estimated cattle made about 55% of the wolves’ diet by biomass.
- A companion study measured tail‑hair cortisol and reported herds sharing rangeland with wolves had 58% higher chronic stress levels than control herds, a result that could affect weight and reproduction.
- The research sampled the Lassen Pack in 2022–2023 and the newly formed Harvey Pack in 2023, and authors say low deer and elk numbers in the region likely push wolves toward livestock.
- Study authors and some ranchers argue the findings justify more active management and greater leeway for ranchers, while conservation groups call for continued protections and expanded nonlethal deterrents; the state has already used lethal removals and increased compensation funding in response to losses.
- Authors note limits to the work — only two packs over two years and disclosed funding from ranch‑aligned sources — leaving open questions about how widely the results apply across California and whether higher cortisol directly reduces herd reproduction.