In both lions and chimpanzees, males cooperate in inter-group conflict with group-mates who are often relatives and with whom they maintain close, life-long social bonds. Anne Pusey (Duke Univ) discusses some of the mounting evidence that successful intergroup aggression and killing results in better resources for group members in both species. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Humanities] [Science] [Show ID: 28348]