Gait characteristics of two macaques, with emphasis on relationships with speed

The gait of a juvenile rhesus monkey as he walked, ran, underwent a run-gallop transition, and galloped on a motor-driven treadmill is described. Additionally, gait data for an adult animal during walking are also presented. Footfall sequences, stride durations, and absolute and relative swing and stance durations for all four limbs are reported, and, where possible, correlated with speed. Furthermore, support patterns and delays between footfalls are presented as a function of speed. The analysis revealed many similarities with previous studies on both primates and other species, but additionally demonstrated that the fore- and hindlimbs may not relate to speed in an identical manner and that galloping is initiated asymmetrically by a single diagonal couplet. The implications of these results in terms of understanding the neural mechanisms by which quadrupeds increase speed are discussed.