Abstract # 59:

Scheduled for Thursday, June 18, 2015 04:45 PM-05:00 PM: (Cascade E) Oral Presentation


E. C. Squires1, K. J. Boose1, F. J. White1, A. Meinelt2 and J. J. Snodgrass1
1University of Oregon, Department of Anthropology, Eugene, Oregon 97403, USA, 2Columbus Zoo and Aquarium
     Humans produce cortisol, a glucocorticoid hormone, in a circadian rhythm that follows a standard pattern of spiking within approximately 30 minutes of waking and then slowly dropping back to baseline throughout the day. A dysregulation in this pattern is linked to stress and negative health outcomes in humans. Studies are beginning to examine cortisol in bonobos, but few studies have characterized whether or not their daily cortisol concentrations also exhibit a similar circadian rhythm. We hypothesized that bonobos would follow a similar diurnal rhythm. Urinary cortisol samples from a captive population of bonobos at the Columbus Zoo and Aquarium (N = 13; 6 male, 7 female) were analyzed for free cortisol concentration by enzyme immuno-assay (Arbor Assays, Ann Arbor, MI) and normalized to mg creatinine. Four samples per individual (2 morning and 2 evening) were assayed and mean morning and evening values were calculated. Mean morning concentrations were significantly higher than evening values (p < 0.01). In all but two individuals, samples followed the diurnal pattern of higher morning than evening concentrations. The two individuals with a dysregulated pattern of cortisol concentration are among the lowest ranking bonobos in the group. Including diurnal rhythm considerations in this type of research has multiple implications for the study of stress behaviors and captive management of primates.