Some aspects of parent‐offspring and sibling relations in a group of rhesus monkeys, with a discussion of grooming

Abstract

Observations of a group of rhesus monkeys living on Cayo Santiago, Puerto Rico show (1) that a rhesus female and her offspring can continue to maintain a distinct relation into the offspring's physical maturity, and (2) that the offspring often develops its strongest relations with monkeys of its own genealogy. Detailed descriptions of relations in several of the genealogies illustrate the above points. The observer identifies relations by the consistent close spacing of individual monkeys, by incidents, such as fights, and by frequency of interactions, such as grooming. Grooming behavior is described. Provisional categories of motor patterns of rhesus monkey grooming are the slide, scrape, and pick. Apparent differences in intensity of grooming may be due to differences in number of slides, scrapes, and picks per time interval, differences in the sequences of the three categories within a bout, and differences in the area covered by each movement. Sequences of slides, scrapes, and picks interrupted by other behaviors, such as scratching, make up grooming bouts. Grooming bouts occur in sequences with bouts of other behavior such as locomotion, fighting, sleeping. Grooming seems to serve a variety of functions although a common element is the relaxing effect on the participants. Monkeys both solicit grooming from others, and groom others without being solicited. Grooming sometimes placates an aggressor following a fight. Monkeys sometimes seem to anticipate aggression and forestall it by grooming the potential aggressor. The case histories of grooming relations show that each relation is unique and is always changing, at least slightly. The human family may have originated when symbolic definition and generalization was given to some such system of behavioral relations already present in populations of the ancestors of the human species.