Extensive adaptation for the care of young infants has been a major, defining characteristic of human and non-human primate evolution. In fact, despite obvious differences in patterns of infant care in humans and other primates, many of the biological factors underlying variation in parenting behavior are probably very similar in humans and other anthropoid primates. Research on the biological causes and consequences of variation in parenting behavior in non-human primate species, especially those phylogenetically closest to humans, i.e. Old World monkeys and apes, can yield new perspectives, information and insight into the origins of variation in human parenting.
Endocrine correlates and fitness consequences of variation in mothering behavior will be investigated for 45 females of known behavioral and demographic history in five groups of wild yellow baboons (Papio cynocephalus) in Amboseli, southern Kenya. Using patterns of behavior, noninvasive fecal hormone sampling, and the Amboseli long-term database, this study will examine the extent to which (1) differences in the mother-infant relationship are predictable from differences among mothers in the profiles of four steroid hormones over late pregnancy and early lactation and (2) differences in the mother-infant relationship predict variation (a) in mothers' future reproduction and (b) infant survivorship.
This project builds on and considerably extends previous research on this topic in non-human primates, which have primarily been constrained to a few individuals of a few species, captive populations, one or two hormones, and invasive hormone sampling. This project represents one of the first rigorous investigations of the biological forces underlying variation in mothering behavior in a wild nonhuman primate population. In focusing on one of the most socially complex and closely related animal models, this project will enhance our understanding of human origins and yield new information and insight into the origins of variation in human parenting while avoiding many of the logistical and ethical difficulties often entailed in studying humans. Furthermore, this study will enhance our understanding of variation in the mother-infant relationship in wild populations and will make important contributions to a comprehensive analysis of life-history variation in wild primates.
In supporting this project, NSF is supporting a major part of the Ph.D training of the co-PI, Nga Nguyen, a first-generation Vietnamese American and the first of her family to receive post-secondary school education. Nguyen has received sponsorship for her research in Kenya through the Institute of Primate Research (IPR), National Museums of Kenya. Nguyen will present preliminary findings of her study in Kenya at IPR and will produce a variety of technical publications spanning several appropriate disciplinary areas, including behavioral ecology, behavioral endocrinology, and biological anthropology. A section of the publicly available Amboseli Baboon Project website (www.princeton.edu/~baboon) will be devoted to this project.
