Term of Award

Fall 2012

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)


Department of Biology

Committee Chair

Lance D. McBrayer

Committee Member 1

Ray Chandler

Committee Member 2

Michelle Cawthorn

Committee Member 3

Michelle Cawthorn


The ability to efficiently move over uneven terrain is critical for most terrestrial animals. Bipedal running is common in lizard species, however the biological advantage of a bipedal running posture remains uncertain. I examined the hypothesis that a bipedal posture is advantageous when crossing obstacles. Particularly, I determined whether kinematic adjustments differ among four focal species with contrasting body forms and ecology. I also examined how sprint speed changed when crossing obstacles with a quadrupedal versus a bipedal posture. I quantified kinematics from high-speed video (300 frames/second) of lizards running down a 3m runway both with and without the presence of an obstacle. Among species, I observed high variation in kinematics, locomotor performance and behavior when crossing obstacles. Within species, mean forward speed (velocity) and kinematics did not change between treatments when employing a bipedal posture. However among species, kinematics differed when using a bipedal posture indicating morphological variation influences how a species utilizes a bipedal posture. Overall, my study suggests an advantage in a bipedal posture when faced with obstacles.