Ontogenetic changes in dental form and tooth pressures facilitate developmental niche shifts in American alligators

Between hatching and late adulthood American alligators Alligator mississippiensis show up to 7000-fold increases in body mass. Concurrent with such changes in body size are absolute and relative modifications in rostral proportions, dental form, feeding capacities and dietary preferences. How these major anatomical changes accommodate prey-resource shifts is poorly understood. In this study, we focus on the effects of ontogenetic changes in bite-force capacities and dental form to address how these factors relate to tooth-pressure generation and diet. We derive absolute values of tooth pressure along the crowns of the most prominent teeth (the first documentation of tooth pressures throughout ontogeny and after initial tooth contact for any animal) and show that these pressures increase with positive allometry during ontogeny. In addition, we discuss how American alligator tooth-pressure values explain their capacities for seizure and oral processing of typical prey, and how tooth-pressure changes facilitate developmental niche shifts in this large-bodied taxon.