Abstract
The study of wild bonobos at Wamba was started by Prof. Kano in 1973. Though it was temporarily interrupted by political insecurity, we have observed bonobos of the same groups for more than 35 years till today. Through this long-term study, we revealed the life history of females who transfer between male-philopatric groups. We showed how immature females developed their socio-sexual behaviors, how they became independent from mother and other members, and how they finally left the natal group. We showed how females immigrated into new groups, and how they established their social status there. When their sons grew up, some females supported them to become alpha males, and had great influence on social relationships within the group as the alpha female and as mother of the alpha male. We also revealed that the peaceful nature in many aspects of bonobo society was linked to the unique sexuality and high social status of females. The prolonged estrus of females seemed to contribute to the lower level of inter-male aggression. Homosexual behavior helped females to resolve tension or conflict and to form affinitive relations with unrelated females. The high social status and initiative of females in feeding and ranging allowed most of the females to attend the mixed-sex party regularly, which in turn helped females to maintain their high status. When two different groups encountered each other, females sometimes went beyond the boundary of the two groups to have affinitive interactions with females or to copulate with males of the other group, which helped the two groups to range together for as long as several days. Thus the studies of bonobos and comparison with the male-dominant society of chimpanzees suggest to us how the changes in sexuality and social status of females may drive their society towards peaceful coexistence.
