Abstract # 6292 Event # 62:

Scheduled for Thursday, June 18, 2015 05:00 PM-05:15 PM: (Cascade E) Oral Presentation


VARIATION IN MALE AGGRESSIVENESS BETWEEN WILD CHACMA BABOONS IN BOTSWANA AND GUINEA BABOONS IN SENEGAL AND THEIR RELATION TO FT AND FGC PATTERNS

U. Kalbitzer1,2, M. Heistermann3, D. Cheney4, R. Seyfarth5 and J. Fischer1
1German Primate Center (DPZ), Cognitive Ethology Laboratory, Goettingen 37077, USA, 2Department of Anthropology and Archaeology, University of Calgary, Alberta, Canada, 3Endocrinology Laboratory, German Primate Center (DPZ), Goettingen, Germany, 4Department of Biology, University of Pennsylvania, Philadelphia, PA, U.S.A., 5Department of Psychology, University of Pennsylvania, Philadelphia, PA, U.S.A.
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     Males usually compete aggressively over access to females, but male aggressiveness varies among species. Because testosterone levels can affect aggressiveness, interspecific variation in aggressiveness might be linked to differential testosterone (T) patterns. Furthermore, glucocorticoid (GC) patterns vary among species because individuals’ allostatic loads depend on the type and intensity of competition. Chacma (Papio ursinus) and Guinea baboons (P. papio) differ in several aspects of their social systems and hence represent a good model to investigate the causes and endocrinological correlates of variation in male aggressiveness. We conducted focal observations on wild chacma baboons in Botswana (N=11 males, 260h) and Guinea baboons in Senegal (N=14 males; 231h), and collected fecal samples (N=258 and N=269, respectively) to determine fT and fGC levels. Male chacma baboons were more aggressive than male Guinea baboons (Wilcoxon-Mann-Whitney test: P<0.001), and male chacma baboons with high fT levels showed more frequent agonistic behaviors (Chisq=5.567, Df=1, P=0.018). Dominance relationships were more consistent in chacma baboons, and we could not detect ranks in Guinea baboons. High-ranking male chacma baboons showed higher fGC levels than low ranking males (Chisq=4.759, Df=1, P=0.029), but rank was not related to fT levels (Chisq=0.928, Df=1, P=0.335). Our findings suggest that different social organizations and mating systems in these baboons have created differential selection pressures on male aggressiveness that may be regulated by differential testosterone patterns.