Primatologists often characterize learned behavioral differences as "cultural" traits, since they arise independently of genetic factors and can be passed on to succeeding generations. Such cultural traditions have been documented in African chimp populations (e.g. using stones to crack nuts). While most of these cases involve tool use, Robert Sapolsky and Lisa Share now provide evidence, in the latest issue of the open-access journal PLoS Biology, of a higher order cultural tradition in wild baboons in Kenya. Rooted in field observations of a group of olive baboons (called the Forest Troop) since 1978, they reveal the emergence of a unique pacific culture affecting this troop.
Typically, male baboons angle either to assume or maintain dominance with higher ranking males or engage in bloody battles with lower ranking males. Females are often harassed and attacked and internecine feuds are routine. However, in the mid-1980s an unexpected outbreak of TB infected and killed the most aggressive males of Forest Troop, drastically changing the gender composition and the behavior of the group; males were significantly less aggressive.
Surprisingly, even though no adult males from this period remained in the Forest Troop in 1993 (males migrate after puberty), new males were also less aggressive than both their predecessors before the outbreak and in comparison with a nearby 'control' troop. Sapolsky and Share also found that the Forest Troop males lacked the distinctive physiological markers of stress. The authors explored how the Forest Troop might preserve this peaceful lifestyle, including the potential impact that females could have in regulating male behaviour. Teasing out the mechanisms for such complex behaviors will require future study but, as Frans de Waal states in a related article in the same issue of PLoS Biol, "with the study by Sapolsky and Share we now have the first field evidence that primates can go the flower-power route". If aggressive behavior in baboons does have a cultural rather than a biological foundation, perhaps there's hope for us as well.
citation: Sapolsky RM, Share LJ (2004) A pacific culture among wild emergence and transmission. PLoS Biol 2(4):e106 DOI: 10.1371/journal.pbio.0020106
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