Spatial selectivity to manipulate portable objects in wedge-capped capuchins (Cebus olivaceus)

We studied the manipulative activity of five wedge-capped capuchins (Cebus olivaceus) confronted with different types of unfamiliar and portable objects: wooden blocks, plastic rings, spoons, and coconuts. Combinatorial manipulations involving two portable objects of the same type were quite frequent. The lately introduced objects, whatever their kind, appeared as the most attractive. Nevertheless, some objects remained very attractive throughout the overall experiment, especially the wooden blocks which elicited more combinatorial and striking behaviors than the other objects. Concerning space, we observed that the individuals choose specific locations to perform their manipulative acts. The spatial distributions of these acts were more concentrated, and less concordant between individuals, in the present study than in two others conducted with the same group but involving the manipulation of familiar objects. This suggests that individual differences were more marked when the subjects manipulated unfamiliar objects than when they manipulated familiar ones. This finding may have applications when the members of a group have to benefit from an enrichment of their environment.