Meeting Abstract
The Agamidae include over 350 species of lizards that exhibit considerable morphological diversity. This provides an excellent opportunity to examine relationships among life history characteristics, body size, head size and shape, sexual dimorphism, and bite-force performance. We examined bite force in the central bearded dragon (Pogona vitticeps), one of the most familiar Australian agamids, which occupies a wide range in Australian semiarid regions. Bite force was obtained in the field from 40 wild specimens using a force transducer with a biting surface covered with leather, to provide a naturalistic biting surface and to protect the animals’ teeth and jaws. Five trials were conducted with each specimen, and the trials were video recorded. The video recordings were used to standardize for variation among individuals and trials in the anteroposterior position of the jaws engaging the transducer, as previous work has shown that this is necessary to provide comparable measurements. Our results indicate that adult males bite harder than adult females of similar body size (snout-vent length) and head length. The mean bite force at the posterior-most teeth was ~175 N for males versus ~100 N for females. A significant positive relationship between bite force and size (snout-vent length and head length) is evident in females, but lacking in males. This pattern may reflect relatively greater variation in adult male condition, compared to females, which may be associated with the costs of male competition for territorial space and/or access to females.
