HERREL, A; O’REILLY, J.C.; RICHMOND, A.M.: Ontogenetic and evolutionary scaling of bite performance in turtles

The design of the trophic apparatus and patterns of resource use often show tight correlations. Yet, relations between head shape and bite performance are often inferred from biomechanical models. Here we test how head size and shape influence bite performance in aquatic turtles by measuring bite forces in vivo. Moreover, we test whether differences in cranial structure and bite performance are related to trophic ecology for a large number of turtle species. The results of our analyses show that intraspecifically, bite performance scales with animal size as expected for isometrically growing systems. The comparative analysis shows that an evolutionary increase in bite force coincides with an increase in head height. Interspecifically, bite force increased positively allometric with carapax length. Clear evolutionary relations between bite force and trophic ecology are observed indicating that species specialising on hard prey show distinct cranial adaptations that allow them to bite harder.