Female Social Rank and Steroid Production in Semi-Free Ranging Lemur Catta on St. Catherines Island, Georgia

Many mammalian species live in complex social groups that profoundly affect the behavior and ecology of their members. In ring-tailed lemurs (Lemur catta) these groups are characterized by female dominance, where females have priority over males for food, grooming, and space. Among females there is also a linear dominance hierarchy. L. catta have a strong matrilineal social core due to females staying within their natal group and males dispersing at sexual maturity. Daughters “inherit” their mother’s social rank. However, it is not known if the matrilineal lines are maintained through learned dominant/aggressive behavior or inherited via genetically determined hormonal blueprints. I studied the intrasexual relationships among females, and correlated social status with the production of three steroid products: estradiol, progesterone, and testosterone. Biological samples (n=192) were taken in summer 2012 from a captive population (n=93) of semi free-ranging L. catta on St. Catherines Island, GA. Samples (n=15) were analyzed for steroids using enzyme-linked immunosorbent assays. Social status was determined via behavioral observations (50 hours). Due to the known negative relationship between cortisol and other steroids, its concentration was also analyzed to investigate a possible effect on agonistic behaviors. No significant differences in steroid concentrations or morphology were found between female ranks during the non-breeding season. Future studies should focus on determining the possible sex differences in androgen-receptor abundance and sensitivity in this and other female-dominant species