Pattern, Distribution, and Function of Greeting Behavior Among Black-and-White Colobus

Various species of primates engage in greeting, a ritualized pattern of nonaggressive behavior that usually occurs during a reunion. Black-and-white colobus (Colobus guereza) perform overhead mounting, mounting, and embracing behavior soon after an aggressive act and in nonagonistic situations. We studied the pattern, distribution, and function of the greeting behavior in 2 captive groups of black-and-white colobus. Overhead mounting was the most frequent pattern, accounting for >60% of all greetings (N=333). In nonagonistic situations, younger subordinate individuals greeted an older dominant individual more frequently than vice versa. A dominant male in a small multimale group frequently initiated contacts with adult females, though he was the oldest in the group. Conversely, the dominant male in a large 1-male group never greeted group members. Immediately after performing the greeting, the greeter groomed the recipient in more than half the cases. In the large group, greeting frequency correlates positively with the age difference between the pair; however, there is no correlation between the relatedness, affiliation frequency, or aggression frequency of a pair in either the small or large group. The results are consistent with the hypothesis that greeting behavior functions as a tension-reducing mechanism in nonagonistic situations. There is no evidence, however, that greeting functions to express social status or to attract a mate. In addition, the frequent greeting by the adult male in the small multimale group may indicate that individuals affirm social bonds via greeting behavior.