title: Unconstrained 3D-kinematics of prehension in five primates: lemur, capuchin, gorilla, chimpanzee, human.
abstract: Primates are known for their use of the hand in many activities including food grasping. Yet, most studies concentrate on the type of grip used. Moreover, kinematic studies remain limited to a few investigations of the distal elements in constrained conditions in humans and macaques. In order to improve our understanding of the prehension movement in primates, we analyse here the behavioural strategies (e.g., types of grip, body postures) as well as the 3D kinematics of the whole forelimb and the trunk during the prehension of small static food items in five primate species in unconstrained conditions. All species preferred the quadrupedal posture except lemurs, which used a typical crouched posture. Grasp type differed among species, with smaller animals (capuchins and lemurs) using a whole-hand grip and larger animals (humans, gorillas, chimpanzees) using predominantly a precision grip. Larger animals had lower relative wrist velocities and spent a larger proportion of the movement decelerating. Humans grasped food items with planar motions involving small joint rotations, more similar to the smaller animals than to gorillas and chimpanzees, which used greater rotations of both the shoulder and forearm. In conclusion, the features characterising human food prehension are present in other primates, yet differences exist in joint motions. These results provide a good basis to suggest hypotheses concerning the factors involved in driving the evolution of grasping abilities in primates.
authors.affiliation: UMR 7179, Département Ecologie et Gestion de la Biodiversité, MNHN, 55 rue Buffon, case postale 55, FR-75231 Paris, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Reghem
authors.forename: Laurence
authors.initials: L
authors.lastname: Chèze
authors.forename: Yves
authors.initials: Y
authors.lastname: Coppens
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Pouydebat
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D011323:Primates / Q000502:physiology*; D060726:Torso / Q000502:physiology; D014741:Video Recording; D014953:Wrist / Q000502:physiology
keywords: Forelimb; Grasping evolution; Kinematics