Meeting Abstract
17.6 Saturday, Jan. 4 11:45 Inter-environmental ballistic locomotion: A kinematic and kinetic analysis of a frog launching from water WILKINSON, K.C.*; NELSON, B.; NISHIKAWA, K.C.; UYENO, T.A.; LEE, D.V.; Northern Arizona University; Northern Arizona University; Northern Arizona University; Valdosta State University; University of Nevada Las Vegas wilkinso@unlv.nevada.edu
Locomotion from one environment to another is essential for any animal that encounters more than one media. Anurans are exceptional examples of animals that are able to move from land to water and vice versa, but do not seem to have a design conflict to perform the two locomotor modes. A handful of frogs are known to skitter, or leap from the water into the air. Anuran skittering is not well understood, but stands as an important locomotion for species that possess the ability. The American Bullfrog was previously unknown to skitter. The frog has been shown to skitter in the case where the main food source in the wild is aerial prey, or to escape water-filled depressions. Few studies have analyzed skittering kinematics, and no known study has attempted to analyze the kinetics of this rare locomotion. Here, land leaping and skittering are compared in terms of joint extension durations, take-off velocities, and kinetic energies to evaluate whether skittering is a land leap applied to water. Biplanar, high-speed videography was used to record land leaping and skittering kinematics. From these videos, the parameters described above could be calculated. However, when a frog leaps from water, water is moved, thus the kinetic energy of the water must be calculated. Using digital particle image velocimetry, an elliptical ring vortex was shed from each from foot, and the velocity and mass were calculated. The results showed that the joints extend one and a half times faster in water and the joint extension sequence was the same. The take-off velocities and overall kinetic energies of both leaps were the same, thus concluding skittering in the American Bullfrog is a land leap applied in water, but in less time.
