Evaluation of fecal testosterone, rank and copulatory behavior in wild male Macaca thibetana at Huangshan, China.

Although male testosterone levels are thought to be linked with the mating system, ecological and social factors complicate the big picture of the function of testosterone in wild nonhuman primates. We examined testosterone correlates with rank and copulatory behavior in male Tibetan macaques (Macaca thibetana) at Mt. Huangshan, China. A total of 426 fecal samples and approximately 453h of behavioral data were collected on five adult males from October 2005 to September 2006. Copulatory behaviors were significantly different between high and low ranking males in the mating season, but not during the non-mating season. No significant correlation between testosterone levels and a male's David's score indicated that testosterone was independent of social rank. Also, copulatory behaviors were positively correlated with fecal testosterone levels in both seasons, regardless of social rank. The present study represents a preliminary assessment of the relationship between testosterone level, rank, and copulatory behavior in a wild environment. The results enrich the picture of testosterone, rank, and copulatory relationships in non-human primates, and may also provide insight into what mechanisms link physiological factors to male reproductive success in natural circumstances.