[modified author abstract] Extended altruism towards unrelated group members has been called a uniquely human behavior. Support for this comes from experimental studies on captive chimpanzees. One study concluded that “chimpanzees are indifferent to the welfare of unrelated group members”. In contrast with these captive studies, observations of potentially altruistic behaviors in different populations of wild chimpanzees have been reported in such different domains as food sharing, regular use of coalitions, cooperative hunting, and border patrolling. This raises the question of what socio-ecological factors favor the evolution of altruism. Here we report 18 cases of adoption, a highly costly behavior, of orphaned youngsters by group members in Taï forest chimpanzees (The Tai National Park covers an area of 454.000ha, it is the last and the biggest rain forest area of West Africa). Half of the adoptions were done by males and remarkably only one of these proved to be the father. Such adoptions by adults can last for years and thus imply extensive care towards the orphans. These observations reveal that, under the appropriate socio-ecologic conditions, chimpanzees do care for the welfare of other unrelated group members and that altruism is more extensive in wild populations than was suggested by captive studies.
Artilce available here (PDF) "Altruism in Forest Chimpanzees: The Case of Adoption," Christophe Boesch, Camille Bolé, Nadin Eckhardt, Hedwige Boesch, PLoS ONE 5(1):: e8901 January 27, 2010
No comments:
Post a Comment