Manual Specialization in Gorillas and Baboons

Abstract

At the start of our studies on hand use in nonhuman primates we took for granted, as did the vast majority of other investigators, the theory that nonhuman primates did not show any bias in manual laterality at the population level, even though some individuals would demonstrate a clear preference for one hand (see Warren, 1980 for a relatively recent example of this position). One ape species, the gorilla (Gorilla gorilla), has sometimes been singled out within this commonly held view (e.g., Fischer, Meunier, & White 1982) because of its supposed right preference, which could be similar to the well established right bias of humans. The case of the gorilla was intriguing and challenging enough for us to undertake a study in which we wanted, among other things, to evaluate their manual preferences. Our study on gorillas followed the observation of the spontaneous hand usage of a group of eighteen Guinea baboons (Papio papio) living in semi-natural conditions (Vauclair & Fagot, 1987a, 1987b). With respect to the distribution of hand preferences, the results obtained in these works were in accordance with the view of a lack of population-level asymmetry in nonhuman primates.