The social behavior of adult male‐infant pairs of rhesus macaques in a laboratory environment

Abstract

Abstract Adult males in nonhuman primate societies exhibit a wide range of behaviors toward immature members of their social group, ranging from virtually continuous nurturance to systematic infanticide. Among macaques, rhesus monkey males in the wild display perhaps the least degree of paternalistic behavior toward conspecific infants. But adult male‐infant rhesus attachments have not as yet been explored in a controlled longitudinal study, even though the mother‐infant bond has received careful attention for several decades. In the present study two pairs of adult male and infant rhesus macaques were housed together without the mother for a period of at least seven months. To minimize the probability of physical harm to the infants, one adult male was present at the birth of the infant with whom it was paired and the other was visually familiarized with the infant for several weeks before being paired with it. Both pairs have shown much less ventral‐ventral contact than mother‐infant pairs and the infants have rarely attempted to gain nipple contact. The female infant now initiates and maintains ventral‐ventral contact much more frequently than the male infant in spite of the higher degree of aggression directed toward her by the male. The adults frequently groom their infants and exhibit varying degrees of both tolerance and aggression. Rough‐and‐tumble play appeared quite early in both pairs and is much more vigorous than mother‐infant play. Recently the male‐male pair has exhibited reciprocal mounting and thrusting. Comparisons are made with data obtained in an earlier study of mother‐infant pairs conducted under nearly identical experimental circumstances. The effects of separating the adult males and infants at seven months are also described.