Fig. 1. Sinusoidal strain (thick black lines) and activation patterns (thin grey lines) in the lateral tailshaker muscle of a western diamondback rattlesnake Crotalus atrox rattling at 30°C and 58 Hz. Data for the right side (top) and left side (bottom) muscles show different lengths because the distance between sonomicrometry crystals varied slightly, not because the muscles have different resting lengths or strains.