Student Prize Award Abstract
1999 Oral Paper Honorable Mention

A NEW "FOUNDER EFFECT" - ESTABLISHMENT OF DOMINANCE IN WILD GOLDEN LION TAMARIN GROUPS

Karen Bales and James M. Dietz Department of Biology, University of Maryland, 1204 Biology-Psychology Building, College Park, MD 20742

Most studies of primate social systems classify species as either male- or female- dominated. Experimental evidence from six groups of wild golden lion tamarins (Leontopithecus rosalia) in Poco das Antas Reserve, Brazil, indicates that, in contests over a preferred food item, neither males nor females are consistently dominant. Instead, groups "founded" (that is, first to settle on the territory) by females are dominated by females and groups founded by males are dominated by males (n=6 groups, 60 observations, p<.05). We compare "female-dominated" and "male-dominated" groups of golden lion tamarins in several areas, including territory size and sex bias of dispersing offspring. We also compare social behavior and cortisol levels of females that dominate their groups with that of females that are in male-dominated groups. This hypothesis may explain some of the conflicting observations on callitrichid mating and social systems in nature and captivity. This research is supported by the National Science Foundation, Sigma Xi, the Biology of Small Populations Training Grant, the University of Maryland Graduate School, TransBrasil Airlines, and the Friends of the National Zoo.