Vestibular System

In an effort to better understand the locomotion of living primates and extinct species including several hominids, Spoor, Wood, and Zonneveld used computer tomography to examine the vestibular system (1994). The vestibular system, housed in the petrous portion of the skull, controls for balance and aids in movement. Agile primates were found to have rather large semicircular canals relative to their body size whereas the opposite was found for less agile primates (Spoor, Wood, & Zonneveld, 1994). Two australopithecine crania were included in the study, Australopithecus africanus and Australopithecus robustus. Both species were found to have a less developed vestibular system than that of modern humans implying that the extent of bipedalism was also less developed (Spoor, Wood, & Zonneveld, 1994). The researchers suggested that australopithecines were not fully bipedal hominids but rather used a combination of bipedal and arboreal locomotion (Spoor, Wood, & Zonneveld, 1994).