Date of Award


Degree Type


Degree Name

Honors Thesis



First Advisor

Shelley Etnier


The shell of a turtle acts as its first line of defense by resisting the compressive forces applied by a potential predator. Changes in shell size and shape that are associated with ontogenesis and sexual dimorphism have been shown to greatly impact the strength a turtle's shell in a variety of species. Here I have tested the effects of ontogenetic changes on the shell strength of Graptemys geographica. The results suggest that the morphological changes that occur during ontogenesis work to increase the overall strength of the shell. The data did not show any obvious morphological or mechanical differences between the shells o[females and males that were expected to arise as sexual dimorphisms became apparent. These results coincide with previous studies on other species of turtles and suggest that juvenile and adult turtles may face different predatory threats, leading to differences in shell shape and size.