Social Interaction Within All-male Gorillas (Gorilla gorilla gorilla, Savage and Wyman 1847) Group at Schumutzer Primate Center, Ragunan, Jakarta

Abstract

A study of social interaction within all-male gorillas had been done at Schmutzer Primate Center, Ragunan, Jakarta. The aim of this study was to observe the affiliate and agonistic behavior of 3 members of all-male gorillas with the absence of their female counterpart to predict the survival ability of the gorillas in captivity. Study was conducted on three male gorillas consist of one silverback and two blackbacks within the age of 11-13 years old. Social interaction was observed among three Interaction Couples (ICs): Silverback and blackback 1 (IC 1), silverback and blackback 2 (IC 2) and between blackbacks (IC 3). Data were based on one month observation using scan sampling and ad libitum methods with five minutes sampling interval without gap. The social behaviors recorded were affiliate and agonistic behaviors. Affiliate behavior in IC1 and IC 3 were dominated by vocalization, meanwhile IC 2 was dominated by approach. Those behaviors showed no dominance hierarchy were needed because of unavailability female to be competed. Agonistic behavior in IC 1 was dominated by chest biting and vocalization, meanwhile in IC 2 was only chest biting and in IC 3 was staring. This behavior was appropriate to common gorilla behaviors in captivity although occurred in low percentages. The agonistic and affiliate behaviors indicated no threat caused within the group members. Therefore, it can decrease any behaviors leading to fatal fight within the group.