Relationship between masticatory rhythm, body mass and mandibular morphology in primates

Abstract Objective It has been proposed that rhythmic movements such as locomotion and respiration have a period proportional to body mass 1/4 . Mastication basically consists of rhythmic alternation of jaw-closing and jaw-opening movements. We studied the relation between masticatory rhythm and body mass in primates, and masticatory rhythm and mandible morphology. Methods We measured the chewing cycle duration (CCD), mandibular length, mandible height, mandible width and distance from the condylar process of mandible to the centre of gravity of the mandible. Body mass was quoted from the literature. Results The CCD is related to mandible morphology and was found to be proportional to body mass 1/6 . Conclusion These findings suggest that masticatory rhythm is correlated with body mass and mandibular morphology, and that scaling rate of masticatory rhythm to body mass is slower than for the other rhythms.