Traditions in monkeys

Traditions, defined as relatively long-lasting behavioral practices shared among members of a group partly via social learning, were studied in monkeys, specifically Japanese macaques, before being studied in great apes. Although apes and humans may share some social learning capacities that are absent in monkeys, a complete understanding of the roots of human culture requires attention to the socioecological conditions favoring traditions, however generated, in animals generally and in multiple behavioral domains. Using the four criteria of intergroup variation, observation of the origin and spread of a novel behavior, dissemination patterned according to age or kinship, or individuals' close observation of others' performance of the behavior before engaging in it, over twenty-five behaviors have been nominated as traditions in free-ranging monkey populations. Tolerant gregariousness has been proposed to increase the likelihood of the emergence of traditions in any behavioral domain. Omnivory and extractive foraging should favor the emergence of foraging-related traditions; strong cooperative relationships and flexible coalitionary structure should favor the emergence of social conventions that function to test social bonds. These conditions are taxonomically widespread. Thus, the current restriction of most reported free-ranging monkey traditions to two taxa (Macaca fuscata and Cebus) is likely to reflect variation in primatologists' research goals, methods, and concepts rather than real interspecific variation in the propensity to generate traditions.