• Macaca arctoides;
  • dominance;
  • secondary sex ratio


Trivers and Willard's theory of sex-ratio adjustment, as applied to cercopithecines, predicts that the ratio of male to female offspring will be greater for dominant than for subordinate mothers. A local-resourcexyhcompetition hypothesis predicts the reverse. To date, results from several species of macaque are inconsistent and often not statistically significant. In this 21 year study, a colony group of stumptailed macaques is added to the species previously studied. Seventy-five offspring were born to eight mothers for whom long-term dominance was established. Chi-square analyses of data from these 75 offspring failed to yield a significant relationship between sex-ratio and mother's dominance; consequently, consistent with a growing body of cercopithecine literature, neither of the competing theories was supported. © 1994 Wiley-Liss, Inc.