Abstract # 87:

Scheduled for Saturday, June 21, 2008 04:15 PM-04:25 PM: Session 11 (Meeting Room 2DEF) Oral Presentation


VARIATION OVER TIME IN GROOMING KIN BIAS AMONG WILD FEMALE TIBETAN MACAQUES (MACACA THIBETANA HUANGSHANENSIS) ON HUANGSHAN, CHINA, SUPPORTS THE TIME CONSTRAINTS HYPOTHESIS

C. M. Berman1, H. Ogawa2, C. S. Ionica1,3, H. Yin4 and J. Li4
1State University of New York, Department of Anthropology and Program in Evolution, Ecology and Behavior, Buffalo, NY 14261, USA, 2School of International Liberal Arts, Chukyo University, JAPAN, 3Laboratory of Comparative Ethology, National Institute of Child Health and Human Development, USA, 4School of Life Sciences, Anhui University, CHINA
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     Variation in the intensity of kin preferences has been documented across species, age-sex classes and types of behavior, but little attention has been paid to variation over time. Using all occurrence and focal-animal data, we examine variation in grooming kin bias intensity (KBI) among wild female Tibetan macaques in one group over 14 years. We test three hypotheses based on socioecological theory, time constraints and risk-related responses. Only the time constraints hypothesis was supported. Grooming KBI was higher when the group was larger [rs=0.96, n=7 data analysis periods, p<0.001], but was unrelated to other indicators of within-group competition. Allies were not necessarily frequent grooming partners; thus support did not depend on maintaining strong grooming relationships. Females groomed similar amounts regardless of group size, but groomed smaller percentages of available partners when the group was larger [rs=-0.79, n=7 data analysis periods, p=0.03], suggesting that they were unable to maintain grooming relationships with all females as the group expanded. The lowest ranking females tended to groom close kin almost exclusively [rs=-0.36, n=63 female-periods, p<0.01], as expected if they had less grooming time to spare than others. Grooming KBI was not higher when stressful external risks (many humans) were present. We suggest that kin-focused grooming networks are shaped at least in part by time constraints and may not be linked even indirectly to within-group competition.