MODELS OF AFFILIATIVE RELATIONSHIPS AMONG FREE-RANGING RHESUS-MONKEYS(MACACA-MULATTA) .2. TESTING PREDICTIONS FOR 3 HYPOTHESIZED ORGANIZING PRINCIPLES

Several organizing principles based on maternal kinship and/or dominan ce relationships, have been proposed to explain the structure of femal e-female macaque affiliative relationships. Social interactions among adult rhesus females of one free-ranging social group on Cayo Santiago , Puerto Rico were observed for four consecutive years to determine th e extent to which patterns of affiliative interaction met several pred ictions of three such hypothesized organizing principles: kin-based at tractiveness, attraction-to-high-rank and the similarity principle. We employed a multiple regression extension of the Mantel test (Smouse e t al., 1986) to test the independent effects of kinship and rank dista nce on measures of affiliation and reciprocity. Close kin not only eng aged in more affiliative behaviour than distant kin (see our companion paper, Kapsalis & Berman, this volume), they were more likely to supp ort one another in agonistic encounters and to exchange grooming for a lliance support and access to drinking water. We found evidence that l ow-ranking females were attracted to high-ranking females in some year s of study, and that grooming by low-ranking females was exchanged wit h tolerance at a monopolizable resource by high-ranking grooming partn ers. However, we were unable to test conclusively for the effects of c ompetitive exclusion. Little evidence was found to support the predict ions of the similarity principle. We concluded that kin-based attracti veness was probably the primary organizing principle operating in the study group but that elements of attraction-to-high-rank may operate i n concert to some extent.