Canine reduction in early man: A critique of three mechanical models

The possibility that projecting maxillary canines interfere with either a «rotary chewing» form of molar occlusion or the lateral excursion of the mandible has been used to suggest two dietary (non-weapon) selection models for canine reduction in the earliest male humans. A third model explaining canine reduction is based on the idea that a projecting mandibular canine could interfere with its tip-to-tip occlusion with the maxillary lateral incisor. In this paper, these three mechanical models are critically reexamined in light of more recent studies of occlusion in extant primates, detailed observations of anterior tooth morphology and wear in Miocene to Recent anthropoids, cheek tooth microwear inA. afarensis, and the currently accepted phylogeny and fossil record of the great apes and man.