title: Bipedal and quadrupedal locomotion in chimpanzees.
abstract: Chimpanzees (Pan troglodytes) habitually walk both bipedally and quadrupedally, and have been a common point of reference for understanding the evolution of bipedal locomotion in early ape-like hominins. Here we compare the kinematics, kinetics, and energetics of bipedal and quadrupedal walking and running in a sample of five captive chimpanzees. Kinematics were recorded using sagittal-plane digital high-speed video of treadmill trials. Kinetics were recorded via a forceplate. Metabolic energy cost was measured via steady-state oxygen consumption during treadmill trials. Consistent with previous work on chimpanzees and other hominoids, we found that the spatiotemporal characteristics, joint angles, ground reaction forces, and metabolic cost of bipedal and quadrupedal locomotion are similar in chimpanzees. Notable differences include hip and trunk angles, which reflected a more orthograde trunk posture during bipedalism, and mediolateral ground reaction forces, which were larger during bipedal walking. Stride frequencies were also higher (and step lengths shorter) during bipedal trials. Bipedal and quadrupedal walking among chimpanzees was similar to that reported for bonobos, gibbons, and other primates. The similarity in cost between bipedal and quadrupedal trials suggests that the adoption of bipedal walking would have had no effect on walking costs for early ape-like hominins. However, habitual bipedalism may have favored modifications of the hip to allow a more orthograde posture, and of the hind limb abductor mechanisms to efficiently exert mediolateral ground forces.
authors: Department of Anthropology, Hunter College, 728 North Building, 695 Park Ave., New York, NY 10065, USA; New York Consortium for Evolutionary Primatology, New York, NY, USA. Electronic address: herman.pontzer@hunter.cuny.edu.
authors: Herman
authors: H
authors: Pontzer
authors: School of Anthropology, University of Arizona, 1009 E South Campus Dr., Tucson, AZ 85716, USA.
authors: David A
authors: DA
authors: Raichlen
authors: Department of Anthropology, University of California Davis, One Shields Ave., Davis, CA 95616, USA.
authors: Peter S
authors: PS
authors: Rodman
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D008124:Locomotion; D008297:Male; D055595:Mechanical Phenomena; D002679:Pan troglodytes / Q000502:physiology*; D014743:Videotape Recording; D016138:Walking
keywords: Biomechanics; Energetics; Hominoid; Human evolution; Ranging ecology