Annett M, Annett J
Department of Psychology, University of Leicester.
Cortex. 1991 Jun;27(2):269-75. doi: 10.1016/s0010-9452(13)80131-1.
Observations of spontaneous reaching for food in 31 captive lowland gorillas found a full range of hand preferences between strong left and strong right, with most animals showing intermediate levels of preference. There was a high degree of consistency between observations made on different occasions for the same animal, showing that degrees of relative preference tend to be stable in individuals. The findings agree with the majority of previous studies of apes and other primates in showing no species bias to one side, with about half the animals left and half right preferent.