Development of Mother-Infant Relationships and Infant Behavior in Wild Blue Monkeys (Cercopithecus mitis stuhlmanni)

Abstract

We studied 12 blue monkey (Cercopithecus mitis stuhlmanni) infants in a wild population during the first six months of their lives, with the goals of (1) identifying factors that explain interindividual differences in the various aspects of the mother-infant relationship and infant behavior, and (2) evaluating the hypothesis that arboreality slows the rate at which infants become independent from their mothers. Infants spent more time in contact with primiparous than multiparous mothers throughout the first six months of life. In addition, primiparous mothers tended to reject their infants at a later stage than multiparous mothers did. A comparison of the time course of development of independence with the timing of maternal rejection suggests that rejection by mothers did not play the major role in the infants’ achieving independence. Mothers who gave birth earliest in their groups were more restrictive during the first weeks of the infant’s life than mothers who gave birth later. Mothers groomed female infants increasingly more than male infants, suggesting the formation of bonds between mothers and daughters in this matrifocal species at a very early stage in life. The rate at which blue monkey infants attained independence from their mothers resembled that of similar sized terrestrial species, but was faster than the few arboreal cercopithecine species that have been studied to date. We suggest that the development of infant independence in blue monkeys reflects the risks of intra-group aggression and predation more than arboreality.