Social behavior in aged rhesus macaques.

This study investigated the relationship between chronological age and social behavior in 42 adult male and female rhesus macaques (Macaca mulatta) in three specific areas: social interactions, social roles, and social networks. While both old males and old females share behavioral differences associated with senescence, this study reports that old females and old males are distinct in their social behaviors, both from each other and from other adults. Many of these differences appear progressive across age classes, e.g., declining across age classes in females and increasing across age classes in males. Old females are less social and have smaller social networks than other females, while the opposite was found to be true of old males. An explanation for the sex-based differences in aged social behavior and social networks reported in this study may originate in rhesus matrifocal social structure.