In this project we are investigating tradeoffs in the jaw muscles of two species of wild mice – the deer mouse (Peromyscus leucogaster) and grasshopper mouse (Onychomys leucogaster). These two species differ in diet and feeding behavior. Whereas Peromyscus is herbivorous, Onychomys is a predatory carnivore often capturing vertebrates that are similar in size or larger. Here we investigated whether Onychomys is specialized for producing large bite forces and wide gapes, and by extension the effect of gape on bite fore during incisor biting in the two species. We collected natural bite forces at different gapes using a custom-made bite force transducer and collected maximum passive gapes on the two species. Compared to Peromyscus, Onychomys does have a relatively wider gape than and is able to maintain larger bite forces at relatively larger gapes. As a follow-up to this project, I am measuring the contractile properties of single muscle fibers from the masseter and temporalis of both species in the lab of Dr. Peter Reiser. I am also measuring sarcomere lengths from masseter and temporalis fibers in the lab of Dr. Andrea Taylor.

Collaborators and Students: Dr. Peter Reiser (Ohio State Univ.), Dr. Andrea Taylor (Duke Univ.), Erika Peiffer (former OU undergraduate), and Sonya Ford (OU undergraduate). Funded by the Provost’s Undergraduate Research Fund and the OUCOM Research and Scholarly Affairs Committee.