GREAVES, W.S.: Modeling the location of the mammalian tooth row

A previous study suggested that mammalian tooth rows should be confined to the anterior seventy percent of total jaw length because that situation maximized the average bite force along the jaw. In the study described here, an estimate of the distance between the right and left tooth rows was determined using a similar analysis. For a sample of tooth rows in different hypothetical locations, relative bite force was plotted from the first incisor at one end of each tooth row to the third molar at the other end. Integrating the equations of these bite force plots gave the area under each curve. (The area under the curve is a measure of the sum of all the bite forces along any given tooth row.) This sum was then divided by the length of the jaw, from joint to incisor, giving the average bite force along an entire jaw. In this model, the location of the hypothetical tooth row where this quotient was largest depended upon the ratio of the jaw width (from joint to joint) to the jaw length (along the midline from joint to incisor). Jaw width is between sixty and eighty percent of jaw length In many mammals. The model predicts that for animals with a W : L ratio within this range, the distance between the right and left tooth rows, measured at the molars, will be between fifty and sixty-three percent of the distance between the two jaw joints.