Achievement

Successful locomotion by animals emerges from the interplay between neuromechanical systems with the physical environment. Sarah Sharpe (an IGERT student), Yang Ding and Daniel Goldman investigated the neuromechanical control strategy utilized by the sandfish lizard during subsurface swimming through sand. This study combined the use of high speed x-ray and visible light video with synchronized electromyogram recordings of axial musculature. They found an anterior-to-posterior traveling wave of muscle activation that corresponded with a single period traveling wave of curvature. EMG intensity increased with depth and was independent of speed; similarly, resistive forces within granular media increased with depth but not speed due to friction-dominated intrusion forces. Models revealed that the waveform utilized by the sandfish maximized speed and minimized mechanical cost of transport, suggesting that sandfish targeted these kinematics to achieve optimal sand-swimming.