INTERLIMB COORDINATION, GAIT, AND NEURAL CONTROL OF QUADRUPEDALISM INCHIMPANZEES

Interlimb coordination is directly relevant to the understanding of th e neural control of locomotion, but few studies addressing this topic for nonhuman primates are available, and no data exist for any hominoi d other than humans. As a follow-up to Jungers and Anapol's ([1985] Am . J. Phys. Anthropol. 67:89-97) analysis on a lemur and talapoin monke y, we describe here the patterns of interlimb coordination in two chim panzees as revealed by electromyography. Like the lemur and talapoin m onkey, ipsilateral limb coupling in chimpanzees is characterized by va riability about preferred modes within individual gaits. During symmet rical gaits, limb coupling patterns in the chimpanzee are also influen ced by kinematic differences in hindlimb placement (''overstriding''). These observations reflect the neurological constraints placed on loc omotion but also emphasize the overall flexibility of locomotor neural mechanisms. Interlimb coordination patterns are also species-specific , exhibiting significant differences among primate taxa and between pr imates and cats. Interspecific differences may be suggestive of phylog enetic divergence in the basic mechanisms for neural control of locomo tion, but do not preclude morphological explanations for observed diff erences in interlimb coordination across species. (C) 1997 Wiley-Liss, Inc.