A goal of primatology is to understand the enormous variability in primate social behavior. Early investigators examined interspecies differences, e.g., that pair-bonding is more common among arboreal than terrestrial primates (Crook and Gartlan 1966). Attention has also focused on geographical differences in behavior within species (Whiten et al. 1999). Often, such differences reflect environmental factors (e.g., a correlation between quantities of rainfall and foraging time) or, in theory, could reflect genetic drift. However, increasing evidence suggests that group-specific traits can also represent “traditions” or “cultures” (the latter term will be used, commensurate with the near consensus among primatologists that the term can be appropriately applied to nonhuman primates).
As traditionally applied to humans, such “culture” can be defined as behaviors shared by a population, but not necessarily other species members, that are independent of genetics or ecological factors and that persist past their originators (Kroeber and Kluckhohn 1966; Cavalli-Sforza 2000; de Waal 2000; de Waal 2001). Thus defined, transmission of culture occurs in apes (McGrew 1998; Whiten et al. 1999; van Schaik et al. 2003), monkeys (Kawai 1965; Cambefort 1981; Perry et al. 2003), cetaceans (Noad et al. 2000; Rendell and Whitehead 2001), and fish and birds (Laland and Reader 1999; Laland and Hoppitt 2003). As particularly striking examples, chimpanzees (Pan troglodytes) across Africa demonstrate variability in 39 behaviors related to tool use, grooming, and courtship (Whiten et al. 1999), and the excavation of near-millenium-old chimpanzee tools has been reported (Mercader et al. 2002).
Nearly all such cases of nonhuman culture involve either technology (for example, the use of hammers for nut cracking by chimpanzees), food acquisition, or communication. In this paper, we document the emergence of a unique culture in a troop of olive baboons (Papio anubis) related to the overall structure and social atmosphere of the troop. We also document physiological correlates of this troop atmosphere, the transmission of relevant behaviors past their originators, and possible mechanisms of transmission.