Abstract # 2389 Event # 138:

Scheduled for Saturday, June 21, 2008 10:45 AM-10:55 AM: Session 15 (Meeting Room 2DEF) Oral Presentation

Intercommunity relations in bonobos: why no lethal raiding?

F. J. White1,2 and M. T. Waller1,2
1Department of Anthropology, 1218 University of Oregon, Eugene, Oregon 97403-1218, USA, 2Institute of Cognitive and Decision Sciences, 1227 University of Oregon, Eugene, Oregon 97403-1227, USA
     Coalitionary groups of male chimpanzees (Pan troglodytes) have been observed lethally raiding the neighboring territories of conspecifics. According to the Imbalance of Power hypothesis, this behavior is an effort to increase fitness through increased access to foraging areas and females. For example, chimpanzees can gain access to additional mates by reducing or eliminating neighboring males, expanding their community range, and absorbing the smaller core ranges of independent females. Bonobo (Pan paniscus) communities, however, often associate peacefully as male bonobos do not form the bands associated with male cooperative killing behavior in chimpanzees. Using data from 5 females and 6 males from 456 hours of ranging data from 1983 to 2007 on wild bonobos in Lomako Forest, DRC, we tested the hypothesis that bonobos do not conduct lethal raids because such behavior would not gain additional females due to female ranging patterns. Unlike chimpanzees, female bonobos ranged in areas that were not significantly different to that of males [ANOVA, F(1,9)=0.522; p=0.49]. Published ranges of chimpanzee females average approximately 70% of male ranges. Bonobo female ranges at Lomako averaged 104% of male ranges. This dispersion of females removes the potential benefit of gaining reproductive females from lethal raids. Rather, bonobo males may benefit from individual strategies including guarding cohesive female parties and predicting female movements. Funding from NSF grants BNS-8311252, SBR-9600547, and BCS-0610233 to FJW.