| Chapter 1: | Introduction |
troop retained its unique social milieu, as it continues to do 20 years later. A multigenerational benign culture had been born in the Forest Troop of baboons.
Other examples of learned social differences involve chimpanzees. In Senegal, these apes frolic about up to their chests in a pond of water from a recent rainfall, grooming and playing in what amounts to a “pool party” (McGrew, 2010). Half a continent away, chimpanzees make elaborate detours through trees or jump from rock to rock so they will not have to step even into shallow water. What is the reason for this difference?
As another example, the principal investigators of nine long-term research programs at different sites compared the cultural behaviors of their animals and found no two populations alike (Whiten, Goodall, McGrew, Nishida, Reynolds, Sugiyama, & Tutin, 2001). In addition, from their list of 39 observed behaviors, only three can be considered aggressive.2 Even within one group, behavior over the years is constantly changing depending on varying sex ratios, age ratios, group size, food supply, and the peccadilloes of individual animals. (Human societies have extensive cultural differences—think Amish compared to hippies—but these are far more extreme because they can be perpetuated by language and written material.)
Whether male monkeys and apes are inclined to be sociable among themselves depends on a number of factors (Hill, 1994; Hill & van Hooff, 1994). Kinship may explain friendly behavior between some male individuals, but many sociable males are not related and relatives are sometimes enemies. Friendly relations are often negatively correlated with competition for such things as food and mating rights. The greater the competition within a group, the more tension and aggression there is. This is all too obvious within provisioned (artificially fed) groups. Alternately, the more competition there is between groups, the less there will be within a group. Usually, the more equal the number of adult males and females, the less tension there is within a group.