A (Bite) Force to Be Reckoned With.

OBJECTIVES: Bite force has received significant attention in biological anthropology, but maximum bite force estimates for a single primate species often span hundreds of newtons. In this synthesis, we discuss the definitions of maximum bite force, review and highlight the variability in methods used to assess bite force in primates, and compare bite force ranges in macaques to bracket maximum force estimates between physiological and mechanical maxima. MATERIALS AND METHODS: Methods of estimating bite force in primates were gathered from the literature along with published estimates of maximum bite force for macaques (Macaca sp.). RESULTS: Maximum bite force can be defined physiologically or mechanically, and methods of estimating bite force can be grouped as in vivo, muscle-based, and craniodental within these two definitions. Physiological estimates occur under natural conditions modulated by sensorimotor feedback, whereas mechanical maximum bite forces ignore muscular and neural limitations. Published maximum bite forces for macaques at the molars vary from 127 N to 898 N, a 771 N range. Using a bracketing approach suggested here, we narrow the estimated bite force range at the incisors to 487-503 N and 503-898 N for the molars. DISCUSSION: This synthesis emphasizes the need for comparisons between in vivo, muscle-based, and craniodental bite force methods in living primates. We propose bracketing bite force estimates between physiological and mechanical maxima in order to provide more reliable bite force estimates and improve understanding of how bite force relates to primate functional morphology and feeding ecology.