Abstract # 13453 Event # 27:

Scheduled for Thursday, August 22, 2019 10:45 AM-11:00 AM: (Room 325) Oral Presentation


ADRENAL HORMONES AND BEHAVIORAL DEVELOPMENT: HOW DOES DHEAS RELATE TO SOCIAL INDEPENDENCE IN WILD CHIMPANZEES?

K. H. Sabbi1, M. N. Muller1,4, Z. P. Machanda3,4, E. Otali4, R. Wrangham2,4 and M. Emery Thompson1,4
1University of New Mexico, Department of Anthropology, MSC01-1040, Anthropology 1, Albuquerque, NM 87101, USA, 2Harvard University, 3Tufts University, 4Kibale Chimpanzee Project
line
     

Hormonal and social developmental processes are coordinated during development. For instance, in humans, increases in the adrenal androgen, DHEAS, mark the pre-pubertal maturation of the adrenal gland the timing of these increases corresponds with several shifts in social behavior including increased independence from caregivers. Wild chimpanzees also experience adrenarche, but the social implications of developmental increases in DHEAS have not been investigated. Here, we use longitudinal data from the Kibale Chimpanzee Project in Uganda ask whether immature chimpanzees (under 10 years, n=27) exhibit increased independence around adrenarche and, if so, whether developmental increases in DHEAS may be responsible. We calculated the proportion of time that individuals spent within 5m of their mothers as a proxy for social independence and calculated age-corrected DHEAS in 6-month age-bins. Then we used GLMMs (R package lmer 1.1-19) to investigate the relationships between social independence, age, and DHEAS. Time spent within 5m of mothers decreased with age (Int=0.923, beta(age)=0.085, p<0.05). However, this decrease was gradual and despite that DHEAS increased with age as time within 5m of mothers decreased, the direct relationship between DHEAS and proximity to mothers was less clear (p=0.23). The coordination between adrenal maturation and social development is likely complex and continued investigation into the developmental roles of DHEAS should expand to include additional social measures, hormones, and energetic factors.