Tooth Morphology and Prey Handling in Durophagous Predators

Abstract

The objective of the study was to better understand functional implications of the interaction between tooth morphology and prey handling in durophagous predators. Our goal was to identify an optimal prey orientation and tooth shape combination that requires the least amount of force to crack hard-shelled prey. Amount of force represents the energy a durophagous predator expends to crack its prey. We modeled the crushing interaction between two sets of tooth models and two Nucella sp. snail shell orientations. Tooth models were grouped into a set that ranges from a convex to concave occlusal surface, and set that has a central cusp with a variable radius. Snail shell orientations included an upside down position, such that the aperture was facing up; and a right-side-up position, such that the aperature was facing down. We found that it took the least total force to crush the shell in its upside down position. At this point of the shell, tight whorls have not formed to strengthen the shell as they have on the upper surface, closer to the shell’s apex, where the aperature is facing down. We also found that as convexity of the tooth increased, the force needed to crack the shell decreased. Finally, we found that as the cusp radius decreased, or as the tooth becomes sharper, the force needed to break the prey item decreased. These results reveal that form and function of tooth shape determine how predators expend energy for prey handling, which affects how predator-prey relationships evolve through space and time. Some durophagous predators may have evolved sharper, more convex tooth morphology to crush hard-shelled prey in preferred orientations.