Adrenocortical responsiveness to immobilization stress in spotted hyenas (Crocuta crocuta)

1. The adrenocortical responsiveness to an induced stressor was monitored in free-living spotted hyenas belonging to a number of social and reproductive categories. 2. No significant differences between sexes, or changes in mean cortisol concentrations during serial sampling within the sexes, could be demonstrated. 3. The extreme individual variance in temporal cortisol profiles recorded in this study is inexplicable, as it was not related to differences in immobilization procedure, sex, age, reproductive or social category. 4. Females, which are the dominant sex in this species, generally showed larger percentage increases in cortisol concentrations during serial sampling. 5. Significant correlations between initial cortisol concentrations, as well as cortisol responsiveness and androgen concentrations, in a number of social and reproductive categories, suggest that these categories do not provide sufficient resolution for the identification of specific dominance-related trends.