Meeting Abstract
Nearly all gliders use limbs when landing, which lessens the impulse on the body and prevents injury. However, gliding snakes (genus: Chrysopelea) land by impacting with their bodies, which must absorb localized forces and dissipate the body’s kinetic energy. Snakes have been anecdotally observed to land on many complex substrates, including the ground, tree branches, tree trunks, and leafy vegetation, but the physics of impact have not been studied. Here we ask, what strategies do snakes use to the dissipate the energy of impact to land safely on branches and leaves? To investigate this question, we recorded and analyzed high-speed video (500 and 2000 fps, Photron APX-RS) of C. paradisi landing after short trajectories (0.5 to 0.8 m horizontally and 0.8 m vertically) onto a horizontal pole as well as into an artificial tree. For snakes landing orthogonally on a bar, the dorsal surface was tracked throughout the landing event and the curvature of the body calculated. At impact, curvature changed near the contact location and propagated anteriorly and posteriorly from the impact site. Curvatures posterior to impact were greater as the body swung below the bar. When landing on a leafy tree, the snakes sometimes used the neck region to hook onto branches and leaf stems, with the neck bending up to 180 degrees laterally. This analysis shows that snakes can successfully land on complex substrates using passive and active changes to local body curvature. Supported by NSF 1351322.
