Social grooming in assamese macaques (Macaca assamensis)

Reciprocity and social bonding hypotheses were evaluated as explanations for observed patterns of social grooming in assamese macaques (Macaca assamensis). In accordance with social bonding, females, as the long-term residents of this matrifocal group, groomed each other and juveniles more often than males groomed one another or juveniles. On the other hand, males groomed females more often and for longer durations than females groomed males and, whereas both males and females groomed juveniles more often than juveniles groomed them, juveniles groomed their elders for longer durations. Male grooming of females did not seem directly related to matings as males are single mount ejaculators and use coercive mating tactics. Male grooming of females could not be accounted for in terms of reciprocity; it was not a simple function of dominance. Although both sexes groomed subordinate females more than vice versa, males groomed dominant males more and females groomed subordinate males more than they received grooming from them. Grooming was concluded to function to establish and maintain affiliative social bonds rather than as a specific mechanism to obtain matings or any other specific reciprocation in terms of services or favors.