Social interactions of adult female rhesus monkeys (Macaca mulatta): Variation with adult sex ratio and social rank
Description
Social interactions of twenty-four adult female rhesus monkeys (Macaca mulatta) were examined in groups containing one, two and three adult males from August 1995 to June 1996. Hypotheses were: (1) Social rank will influence female access to mates: Higher-ranking females would have priority of access to mates. (2) Adult sex ratio will influence female interactions with adult males and females: In groups with fewer males per female, female access to mates will depend on dominance rank. In groups with more males per female, female access to mates will depend on active competition: All females will initiate more frequent affiliative and sexual interactions toward males, and exchange more frequent agonistic behaviors with other females. (3) Difference in female access to males in the three groups will disappear after the breeding season The four highest and the four lowest ranking females in each group were chosen as focal animals. Affiliative, sexual, and agonistic interactions between focal females and other adults were recorded using focal animal sampling method (Altmann, 1974). Female interactions in the three groups were compared using 2-way ANOVAs for fall, transition period and spring. Changes of female interactions over time were analyzed using three-way ANOVAs with repeated measures Results did not support the hypothesis of female's social rank influencing access to mates but supported the hypothesis that the number of adult males affects female access to mates. Females in multi-male groups significantly initiated more frequent and maintained longer proximity to males during the early breeding season than females in one-male groups. This suggests female-female competition for mate choice in multi-male groups. Results did not support the hypothesis of subsiding differences in female access to mates after the breeding season. Post-conception estrus in one of the multi-male groups, and peaks of conceptions present in multi-male groups, suggest female competition for mates in multi-male groups