Functional strategies during tool use tasks in captive bonobos
Résumé
Primates have highly developed capacities for gripping and manipulating that differ between species. In this context, the human hand is considered as unique based on its functional characteristics. However, the real dynamic manual abilities of primates remain poorly known. The aim of the present study was to quantify the functional strategies (manual postures and in-hand movements) used by 8 captive adult bonobos during a new complex tool use task, consisting of recovering food in a wooden maze placed outside the cage. We found 1) that each individual presented his own manipulations techniques and 2) a difference between males and females with a greater variability in manual postures for males and more in-hand movements for females. Bonobos had individual specificities that could reflect the specialization of their manipulation strategies, especially here for a complex task. They were able of in-hand movements similar to humans and chimpanzees. The observed sex effect could reflect the hierarchy with females taking/having more time to perform a task. These preliminary results show the necessity to pursue the quantification of object manipulation in different species for new tasks and with new methods to better understand the manual specificities of each species.