Inner Ear Canal Morphology

The semicircular canal system of the inner ear helps coordinate body movements, in particular by stabilization of gaze during locomotion. In mammals, the size of the semicircular canals varies interspecifically with body mass. However species with fast and jerky locomotion have relatively larger canals. Within hominoids, and taking into account body mass, modern humans contrast with apes by displaying enlarged anterior and posterior canals and a somewhat reduced lateral canal. This is interpreted by some as resulting from the establishment of the extant form of bibedalism. Similar conditions are met in Homo erectus, but Australopithecus still display primitive conditions.The functionally important planar orientations of the semicircular canals is identical in humans and in apes.