Human Evolutionary Biology, Harvard University
Saturday 4:00-4:15, 200ABC
Previous work on wild ring-tailed lemurs from Beza Mahafaly Special Reserve (Beza) has identified a number of behavioral sex differences in this species that arise before sexual maturity, suggesting a possible role for sex-typed socialization in behavioral development. Socialization can occur in two ways—via: sex-differential responses by subadults to the same social experiences and/or sex-differential treatment of subadults by others. This study uses behavioral data collected during focal animal follows over 12 months on three age cohorts of Lemur catta at Beza (infant, 0-11 months, n=29; juvenile, 12-23 months, n=8; adult, n=13). GLMMs were fit to test for sex differences in rates at which subadults received approaches, grooming, aggression, rejections, and dominance by mothers or other adults of each sex. Few significant sex differences in treatment by adults were found. Infant cohort females were supplanted more often by adult females (p=0.02) and juvenile cohort females received more aggression from their mothers (p=0.003) than male peers. These results indicate that sex-differential treatment of subadults by adults is either rare or substantially less marked than subadult behavioral sex differences themselves. Rare and/or subtle sex differences in treatment by others should not be discounted as potentially important drivers of sex-typed development, but I argue that these particular cases are more reasonably interpreted as responses to sex differences in subadult behavior rather than causes of it. If so, these results suggest that ring-tailed lemur sex-typed development is not strongly shaped by adults and arises, instead, from subadults themselves.
This study was funded by The L.S.B Leakey Foundation, a Sigma-Xi Grant-in-Aid- of Research and the Graduate and Professional Student Association and SHESC at Arizona State University.