Jumping on water: Drag based propulsion in E. cyanophlyctis and Acris spp.
The exit and entry of bodies across a water/liquid interface are important for many engineering and biological problems, such as submarine surfacing, torpedo launch/maneuvering, and the basilisk lizard running on water. Despite the significance of these phenomena across various disciplines, the underlying physics are not entirely understood. Studying the physics and mechanisms behind animal locomotion on the water surface can not only yield new insight into the underlying biomechanics that produces the behavior, but also positively impact the design of devices performing on the air-water interface.
The Indian Skipper Frog (Euphlyctis cyanophlyctis) presents an excellent model for studying biolocomotion at the air-water interface. Much like the basilisk lizard, E. cyanophlyctis has the ability to jump or ‘skip’ upon the surface of the water. However, E. cyanophlyctis displays an additional unique behavior – this frog is able to vertically jump three body lengths from a static floating position. Because these behaviors demonstrate both water exit and entry using the same physiological mechanism this organism is a good model to explore the physics behind drag-based propulsion water exit and entry mechanisms.