Biopsychosoc Med Click for full paper
The costs of dominance: testosterone, cortisol and intestinal parasites in wild male chimpanzees
Clip: Direct associations between testosterone, rates of aggression, and dominance rank have been identified in several species, including nonhuman primates [17,18]. Conversely, several studies have failed to demonstrate significant correlations between aggression, dominance rank and testosterone levels [19,20]. In fact, there is surprisingly little evidence that short-term changes in testosterone levels correlate with increased levels of aggression, and fluctuations in testosterone levels in healthy, eugonadal individuals over time do not necessarily predict changes in levels of aggression within individuals, human or nonhuman [reviewed in  and ]. Rather, testosterone may have a permissive effect, potentiating pre-existing patterns of aggression . Testosterone is also more frequently associated with aggression and dominance rank during situations of social instability, such as during challenges by conspecific males for territory or access to mates, the establishment of territorial boundaries, the formation of dominance relationships, or in the presence of receptive females .