Meeting Abstract
Snakes display several locomotor modes which allow them to overcome a wide range of terrain challenges. Sidewinding is a mode which allows snakes to move across yielding sand with high speed, low cost of transport, high endurance and maneuverability, and the ability to ascend sandy slopes. However, sidewinding locomotion also cuts a broad path through the environment, making it vulnerable to obstacles. To determine the extent to which obstacles disrupt sidewinding, if at all, we encouraged four sidewinder rattlesnakes (Crotalus cerastes) to cross a line of vertical pegs while recording overhead video. The method used to negotiate the peg line depended on the orientation of the peg relative to the anterior-most static region. If the peg contact occurred posterior to a static contact, the lifted moving portion of the snake was deformed around the peg and dragged through as the snake continued sidewinding (which we refer to as the “propagate through” behavior, 71% of trials), otherwise the snake would perform a “reversal” (23% of trials) (Astley et al, PNAS, 2015) to reorient or abandon sidewinding in favor of concertina locomotion (6%). Traversing the peg line typically resulted in a decrease in velocity, but the reduction in speed was much greater in concertina (mean +- s.d.: 64% +- 9% loss of speed) compared to reversals (50% +- 15% loss) and “propagate through” (46% +- 22% loss) responses. We hypothesize that the “propagate through” behavior depends upon compliance of the lifted segment due to unilateral muscle activity.
