Susan Longest

Susan received her Ph.D. in Evolutionary Biology in 2009.

Current Position: Assistant Professor, Biological Sciences Department, Colorado Mesa University

Susan Longest’s research focuses on the development, acquisition, and maintenance of dominance in ring-tailed lemurs. Many social group-living animals form dominance hierarchies to reduce competition between group members for access to food and mates. Dominance ranks are positively correlated with access to resources and reproductive success. Despite its importance to many group-living animals, very little research has investigated the mechanisms underlying the development and acquisition of dominance. The studies that have been conducted focus on female-bonded societies in which males are dominant to males and immature individuals inherit their mother’s rank. To expand the current understanding of dominance among immature individuals, Susan is studying the development and acquisition of dominance in ring-tailed lemurs which are characterized by female dominance, i.e. all females are able to elicit submissive behaviors from all males. Furthermore, maternal rank is not inherited in this species, thus attributes of the immature individuals themselves are investigated in relation to dominance acquisition. Susan collects behavioral and hormonal data (from fecal samples) to investigate the mechanisms underlying dominance acquisition among infants (when females are not yet dominant to males) and among reproductively mature individuals as they enter the adult hierarchy and females become dominant to males.

Susan is also investigating social relationships among adult females to understand how females maintain this female-dominant society. By investigating dyadic social relationships in the context of the entire social group, Susan is addressing how social connectedness is associated with social support among adult females. Ring-tailed lemurs were studied at the Beza Mahafaly Special Reserve in southwestern Madagascar and on St. Catherines Island, GA, USA, to investigate how food availability and predation risk impact social connectedness of females. This project will greatly expand our current understanding of the acquisition of dominance and how dominance relationships are maintained in adulthood by including less-studied dominance systems into the current body of literature.