Maximum Bony Gape in Primates

Ellen E.I. Fricano, Jonathan M.G. Perry

Research output: Contribution to journalArticlepeer-review


Maximum jaw gape has important functional implications for behavior and feeding habits in primates. It has been suggested that gape is correlated to canine height and ingested food size. Extending these correlations to the fossil record would provide insights about the diets and/or social behavior of extinct primates. However, this can be problematic due to uncertainty about size and location of musculature, and it depends on reliability and repeatability of maximum gape estimation using only skeletal elements. In this study, maximum bony gape (MBG) was estimated using reliable landmarks and repeatable methods. The cranium was fixed in position and then the mandible was rotated and translated to the point immediately prior to loss of condyle-glenoid contact. Then it was photographed in a steady position using an adjustable wooden frame. This protocol allowed for photographs and linear measurements to be obtained for many museum specimens in a short time. The sample included 203 individuals, representing 42 species of primates. When scaled for body size, linear MBG correlates with maximum anesthetized gape (Hylander: Am J Phys Anthropol 150 (2013) 247–259), ingested food size (Perry and Hartstone-Rose: Am J Phys Anthropol 142 (2010) 625–635), and canine length but not condylar height. Anat Rec, 302:215–225, 2019.

Original languageEnglish (US)
Pages (from-to)215-225
Number of pages11
JournalAnatomical Record
Issue number2
StatePublished - Feb 2019


  • craniomandibular morphology
  • dietary adaptation
  • food size
  • functional morphology

ASJC Scopus subject areas

  • Biotechnology
  • Anatomy
  • Ecology, Evolution, Behavior and Systematics
  • Histology


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