The Upright Ape: A New Origin of the Species
by Aaron G. Filler, MD, PhD
Figure 9-4 Gibbon Bipedalism
Figure 9-4 - Gibbon running styles on the ground.
These apes do use tripedal and quadrupedal “crutch walking” occasionally, but their fundamental running style is hauntingly similar to human running .
From: Vereecke, E. E., K. D'Aout and P. Aerts (2006). Locomotor versatility in the white-handed gibbon (Hylobates lar): a spatiotemporal analysis of the bipedal, tripedal, and quadrupedal gaits. Journal of Human Evolution 50(5): 552-67. Photograph and drawings reproduced by permission of Elsevier.