Work

Wolf Presence Disrupts Seasonal Variation in Hair Cortisol Among Free‐Ranging Beef Cattle

Year: 2026

Type: article

Abstract: ABSTRACT Understanding how predator reintroduction indirectly affects prey physiology remains poorly understood. We examined hair cortisol concentrations in 79 beef cattle from nine herds across California's Sierra Nevada, comparing herds exposed to the Lassen Wolf Pack with unexposed herds. We collected hair samples before and after summer grazing ( n = 158 samples) and used Bayesian multilevel regression to test for effects of wolf presence. Wolf‐exposed herds showed a 58% reduction in temperature sensitivity compared to unexposed herds (where cortisol decreased 13.5% per 1°C), suggesting altered seasonal cortisol regulation. These preliminary results point toward a potential physiological mechanism by which predator reintroduction may indirectly affect prey, with implications for understanding how recovering carnivores could influence prey physiology, animal welfare, and productivity.

Source: Ecology and Evolution

DOI: 10.1002/ece3.73431