Abstract # 123:

Scheduled for Saturday, June 21, 2008 08:45 AM-08:55 AM: Session 13 (Meeting Room 2DEF) Oral Presentation

Free-ranging alpha male chimpanzee grooming patterns in Gombe National Park, Tanzania: implications for dominance ‘style’

M. W. Foster1,2, I. C. Gilby3, C. M. Murray2, A. Johnson4 and A. E. Pusey2
1Lincoln Park Zoo , Lester E. Fisher Center for the Study and Conservation of Apes, 2001 N. Clark St., Chicago, IL 60614, USA, 2Jane Goodall Institute's Center for Primate Studies, University of Minnesota, 3Department of Anthropology, Harvard University, 4Department of Statistics, University of Minnesota
     In social primates, individuals use various tactics to increase and maintain high rank. Grooming is common among chimpanzee (Pan troglodytes schweinfurthii) males, and may be used as one of several strategies to attain and continue dominance. We examine grooming patterns of alpha males (N=3: FD, FR, WL) in Gombe National Park, Tanzania, using 694 full-day focal-follow samples from 1992-2001. We demonstrated that these males differed significantly in their tendency to groom with other males and reasoned that body mass may be one possible determinant of these differential grooming patterns. The largest male, FR (51.2 ± 2.4 kg), exhibited the lowest participation in grooming when compared to the WL (37.0 ± 1.6 kg) [two-sample Wilcoxon Signed Rank Tests: W=3056, p<0.005] and FD (44.8 ± 2.62 kg) [W=3334.5, p<0.005]. Within-individual grooming patterns remained consistent before and after the males’ alpha period, with no reports showing statistical significance when comparing grooming rates between the different rank periods. Males may compensate for smaller body size by investing more time and energy in grooming in order to ensure coalitionary support from subordinate males. Grooming may be one of several behaviors that correlates with larger patterns of particular dominance ’styles’ that reflect an individual’s tendency to use cooperative and/or agonistic tactics when interacting with subordinates.