Defense of females, but not social status, predicts plasma androgen levels in male spotted hyenas

A positive correlation between male social status and testosterone levels is expected and often found in social species with high rates of agonistic interactions or when social relationships among males are unstable. In contrast, in species with low rates of agonistic interactions or when social relationships are stable, testosterone levels should not correlate with social status. The "challenge hypothesis" predicts that androgen levels should rise during periods of courtship or mate guarding. We addressed these questions in free-ranging spotted hyenas, a species with low rates and low intensities of aggression among males but where males spend extensive effort to court females. In males, we measured testosterone, its precursor androstenedione, and its metabolite 5alpha-dihydrotestosterone. As predicted, testosterone levels were significantly higher and androstenedione levels tended to be higher in males that, at the time of sampling, defended a female, compared with males that did not defend a female. Also, as predicted, there was no correlation between social status and androgen levels in male spotted hyenas.