Videos

Bipedal running has evolved numerous times within various groups of lizards, however its function, if any, has remained unclear. The videos below are from two studies and show that a bipedal running posture can be advantageous in negotiating obstacles (see Tucker & McBrayer 2012 (top); Parker & McBrayer 2016 (bottom). Both videos are of the Florida Scrub lizard (Sceloporus woodi) running in the lab and have been slowed down. The top video shows how the use of a bipedal posture enables the animal to clear an object roughly the same height as its body length. The lower video is spliced together from two adjacent cameras along a one meter raceway. Here, locomotion involving two obstacles (shown) was studied, and the obstacle heights are 30% of the lizard's hindlimb length. You can see that the lizard touches the first obstacle with his left hind limb, but does not touch the second obstacle at all.