Altruistic interference shown by the alpha-female of a captive troop of rhesus monkeys (1986)

Reinhardt, V., Dodsworth, R., Scanlan, J.

Abstract

Interferences in aggressive disputes were recorded in a captive troop of rhesus monkeys (Macaca mulatta) comprising 19 mature females, 2 mature males and 12 immatures. The top ranking animal – the oldest female, Alpha, 23 years of age – was the only one who consistently interfered in favor of victims, never of aggressors. This protective, dispute-breaking strategy was distinguished by the following facts: (1) None of the supported monkeys shared genes with Alpha; (2) Alpha had no preference for aiding particular individuals; (3) Alpha's high-risk interference (against aggressors) was never reciprocated; and (4) there was no evidence that Alpha's strategy aimed at the improvement of dominance standing. It was concluded that Alpha's behavior may represent an example of altruism.