Évolution de la préhension chez les primates humains et non humains : la précision et l'utilisation d'outils revisitées

The term “precision”, involving the contact between the tips of thumb and the index is generally attributed to humans, tool use and associated with morphological criteria. Identified in fossils, those criteria are used to assert that they manipulated tools. Observations of 69 individuals belonging to Catarrhines and Platyrrhines allowed us to quantify surfaces of fingers used during simple tasks of grasping both small and large objects, as well as during complex tasks of proto-tool and tool use. We concluded that precision grasping is not peculiar to humans and that it is not systematically linked to tool use. These results allowed us to discuss morphological traits used till now to deduce precision and tool use from the fossils. Besides, our analyses let appear a recurrent proximity between the capuchins and the humans, species distant in a phylogenetic point of view, suggesting the possible existence of functions and close behaviours in spite of great genetic distinctions.