Rethinking incisor size and diet in anthropoids: Diet, incisor wear and incisor breadth in the African apes


  • Melanie A. McCollum

    Corresponding author
    1. Department of Cell Biology, University of Virginia School of Medicine, Charlottesville VA 22908-0732
    2. Biological Anthropology Program, Division of Basic Medical Sciences, Kent State University, Kent OH 44242
    • Department of Cell Biology, University of Virginia School of Medicine, PO Box 800732, Charlottesville VA 22908-0732, USA
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In a seminal study Hylander (1975) concluded that the length of the incisor row in catarrhines considered frugivores is longer relative to body mass than in those classified as folivores. Assuming that large fruits require greater incisal processing than do leaves, stems, berries, and seeds, he argued that the larger incisors of frugivores increased their resistance to wear. The present analysis examines diet, incisor wear, and incisor crown breadth in cranial samples of western lowland gorillas and chimpanzees. Incisor wear rate was assessed on the basis of the extent of incisor crown reduction observed at sequential stages of first molar wear. Incisor metrics were obtained from the unworn teeth of juveniles. Results suggest that incisor wear is greater in the more folivorous western lowland gorillas than in more frugivorous chimpanzees. Moreover, incisor crown dimensions do not differ appreciably among African apes. These findings fail to support the hypothesis that slower wear rates are associated with broader incisor crowns, and raise new questions regarding the significance of incisor row length in anthropoids. Am J Phys Anthropol, 2007. © 2007 Wiley-Liss, Inc.