Meeting Abstract
Body size affects morphology, physiology, and even behavior across the tree of life, including locomotion ranging from invertebrate peristaltic crawling to tetrapod running. Previous studies on scaling of terrestrial locomotion have shown that kinematics scale inter- and intraspecifically for walking, running, and jumping. However, many animals move terrestrially without limbs, and they face different locomotor challenges than do limbed animals. Because limbless terrestrial animals range across orders of magnitude in size, and because they move so differently than limbed animals do, studies of scaling of limbless locomotion would deepen our understanding of the diversity of effective movement on land. We examined the scaling of sidewinding locomotion in the rattlesnake Crotalus cerastes by collecting various morphological measurements and high speed video of 74 sidewinder rattlesnakes ranging in size from 8 g to 272 g. Several morphological characters scaled allometrically with body mass, including tail length, elongation ratio, head length, head width, head length : width ratio, and head width : neck width ratio. In addition to the changes in body shape, we expected changes in the kinematics of sidewinding motion, perhaps mediated in part by changes in body shape. Preliminary results suggest that certain kinematic variables, such as the height to which the snakes lift their bodies as they move forward, scale allometrically. We also analyzed instantaneous velocity and acceleration of points along the body, as well as local curvatures. Moreover, individual variation in morphological characters will allow us to examine whether aspects of morphology such as relative tail length, slenderness, or number of body vertebrae affect sidewinding kinematics.
