Handedness and bimanual coordination in the lowland gorilla.

One could hypothesize from previous studies that gorillas, as a group, might show a right-hand preference, making this species an exception among nonhuman primates. A study of 10 captive gorillas observed while reaching for food and tested on unimanual and bimanual tasks does not support this conclusion. Instead, the present study found (a) a symmetrical distribution of subjects with right-hand (n = 3), left-hand (n = 3), and no hand preference (n = 4) when simply reaching for food and (b) a left-hand preference by 7 of 8 gorillas tested on a spatial task requiring precise alignment of two openings. These results stress the importance of considering the kind of task employed in the assessment of lateral preferences. Furthermore, it is suggested that it might be useful to distinguish between the handedness of a gorilla when simply reaching and its manual specialization for novel and complex tasks.