Manual lateralization in wild redfronted lemurs (Eulemur rufifrons) during spontaneous actions and in an experimental task

Abstract

The dominant use of one hand is a striking feature of humans, but manual lateralization can be found in a variety of other species as well. In primates, the lateralization in hand use varies among species and several theories such as the "postural origin," "task complexity," or "development theory" have been suggested to explain this variation. In order to contribute comparative data on this phenomenon from a basal primate, we studied manual lateralization in wild redfronted lemurs (Eulemur rufifrons). Data were collected on four groups at Kirindy Forest, western Madagascar, during spontaneous actions and by confronting them with artificial feeding boxes. The lemurs did not exhibit manual lateralization on a group level in either condition. More individuals showed a hand preference in the experimental task, and the preferences were stronger compared to spontaneous actions. The direction of individual hand preferences was not consistent across the two conditions. The results of this study show that measuring manual laterality in different contexts can yield different results. Manual lateralization in wild redfronted lemurs therefore seems to be flexible and situation dependent and probably not ecologically relevant in their natural habitat.