Abstract # 161:

Scheduled for Sunday, September 14, 2014 07:00 PM-09:00 PM: Session 22 (Decatur B) Poster Presentation


S. D. Breaux1, J. J. Breaux1, S. L. Watson2 and M. B. Fontenot1
1University of Louisiana at Lafayette New Iberia Research Center, PO Box 13610, New Iberia, LA 70562, USA, 2Department of Psychology, University of Southern Mississippi
     Urinary cortisol measures provide noninvasive means for examining hypothalamic-pituitary-adrenal axis activity in primates. While some research indicates individual stability and potential value in predicting future behavior, there are psychological and physiological factors that may influence cortisol levels. We investigated the effects of age, sex and season on morning cortisol levels in juvenile to adolescent chimpanzees (n=28 (19M, 9F); aged 3.17-9.83 yrs (mean=6.43 yrs)). Using positive reinforcement training, urine samples were collected weekly between 0800-1100 hrs from March 2008 through May 2009. Cortisol was corrected for specific gravity, residualized for time of collection and averaged for each subject for five seasons: Spring 2008 (March-May), Summer 2008 (June-August), Fall 2008 (September-November), Winter 2008-2009 (December-February), and Spring 2009. Repeated measures ANCOVA, co-varying age, revealed a significant effect of season (F4, 104 = 7.91, p<0.001), indicating that cortisol was lowest in Spring compared to other seasons, and a season by age interaction (F4, 104 = 8.84, p<0.001). Univariate analysis indicated cortisol levels in juveniles decreased significantly over time (F1, 25 = 8.33, p<0.01) and were significantly lower than adolescent levels in Spring 2009 (F1, 25 = 5.09, p<0.05). Adolescent levels increased over time (F1, 25 = 8.72, p<0.01). Over time, cortisol levels vary between juvenile and adolescent chimpanzees and may reflect factors such as post-weaning stress among juveniles and degree of reproductive maturation among adolescents.