A practical guide to the study of social relationships

Behavioral ecologists have devoted considerable effort to identifying the sources of variation in individual reproductive success. 1 - 5 Much of this work has focused on the characteristics of individuals, such as their sex and rank. However, many animals live in stable social groups and the fitness of individuals depends at least in part on the outcome of their interactions with other group members. For example, in many primate species, high dominance rank enhances access to resources and reproductive success. 4 , 5 The ability to acquire and maintain high rank often depends on the availability and effectiveness of coalitionary support. 6 Allies may be cultivated and coalitions may be reinforced by affiliative interactions such as grooming, food sharing, and tolerance. 7 , 8 These findings suggest that if we want to understand the selective pressures that shape the social behavior of primates, it will be profitable to broaden our focus from the characteristics of individuals to the properties of the relationships that they form with others. The goal of this paper is to discuss a set of methods that can be used to quantify the properties of social relationships.     

Triadic interactions among Macaca radiata: Passports and buffers

Male members of a group of captive Macaca radiata at the California Primate Research Center held and carried infants as they approached or were approached by higher-ranking males and as they were threatened by other males. Male infants between the ages of 25 and 84 weeks were involved in triadic interactions more frequently than were female infants of any age or male infants of other ages. That males were less likely to be harassed while huddling with or embracing infants suggested that infants provided an effective buffer against aggression.