The physiology of predator stress in free‐ranging prey

M.J. Sheriff, C.J. Krebs & R. Boonstra (2009) The sensitive hare: sublethal effects of predator stress on reproduction in snowshoe hares. Journal of Animal Ecology , 78 , 1249–1258. Ecologists have only begun to understand the physiological mechanisms underlying individual‐ and population‐level responses of prey‐ to predator‐related stress. Sheriff, Krebs and Boonstra advance this field by providing evidence that predator‐induced increases in glucorticoid concentrations in wild female snowshoe hares ( Lepus americanus ) impact both litter size and offspring condition. They hypothesize that the glucocorticoid‐mediated effects on reproduction provides an adaptive benefit: mothers ‘programming’ their offspring to be timid and risk‐averse in high‐risk environments should increase their survival probability. This research illuminates the connection between stress physiology and population‐level changes and demonstrates the surprisingly far‐reaching impact of predation risk.