Plasma cortisol levels and dominance in peer groups of rhesus monkey weanlings

Abstract

Determinations of plasma cortisol levels in rhesus monkey infants were obtained before and shortly after they were separated from mother and placed together in small social groups. Differences in pregrouping (baseline) plasma cortisol levels between two infants were good predictors of the direction of the social dominance relationship established between them. This association between lower baseline cortisol values and dominance was not dependent on sex or small differences in age and weight between the infants.