Male affiliation, cooperation and kinship in wild chimpanzees

Long-term field research has revealed that male chimpanzees, Pan troglodyte s, affiliate and cooperate in several contexts. Assuming close genetic rela tionship among males, affiliative and cooperative behaviour have been hypot hesized to evolve through the indirect effects of kin selection. We tested the hypothesis that matrilineal genetic relatedness affects patterns of mal e social affiliation and cooperation in an unusually large community of chi mpanzees at the Ngogo study site, Kibale National:Park, Uganda. Field obser vations indicated that six behavioural measures of affiliation and cooperat ion among 23 adult males were significantly correlated with each other. Seq uences of the first hypervariable portion of the mtDNA genome revealed that three pairs of males and one quintet shared mtDNA haplotypes. Matrix permu tation tests using behavioural and genetic data showed that males that affi liated and cooperated with each other were not closely related through the maternal line. These findings add to a growing body of empirical evidence t hat suggest kinship plays an ancillary role in structuring patterns of wild chimpanzee behaviour within social groups. (C) 2000 The Association for th e Study of Animal Behaviour.