Affiliation and reciprocity in sibling and peer relationships among free-ranging immature male rhesus monkeys

Abstract

The social relationships of immature male rhesus monkeys ( Macaca mulatta) were studied during 1977, 1978 and 1981 at the Cayo Santiago colony, Puerto Rico. Three types of social relationship were selected for comparison: the sibling relationship, the strong peer relationship and the weak peer relationship. Sibling relationships were initially distinguished from peer relationships on the basis of individual characteristics (age and relatedness), whereas the two types of peer relationship were initially differentiated on the basis of criteria that concerned their structure. Although the three types of relationship showed certain similarities these were far outweighed by differences in the content, diversity, qualities and the relative frequency and patterning of their interactions, and the degree to which their interactions were characterized as reciprocal or complementary. These findings are discussed in relation to a number of questions concerning the sturucture of relationships and it is concluded that, in broad terms, the three types of relationship can be contrasted in terms of a multidimensional quality, their degree of affiliation.