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A kinematic and kinetic analysis of a frog launching from water using digital particle image velocimetry

<p> Locomoting from one medium to another is crucial to the survival of many animals. Bullfrogs (<i>Lithobates catesbeianus</i>) leap from water into air to capture aerial prey or to escape water-filled depressions. Here, kinematics and kinetics of leaping on land and water are described and compared. High-speed videography was used to record both types of leaps and these videos were analyzed for their kinematics (joint extension, duration, and take-off velocity) and to calculate kinetic energy at takeoff. A custom digital particle image velocimetry (DPIV) instrument recorded the vortex ring shed from each frog foot. Joint extension sequences of both types of leaps and differences in take-off velocities were statistically identical. The kinetic energy contained in the two vortices shed from each foot was small in magnitude compared to the kinetic energy in the body of the frog. This suggests that the kinetic energy transfer from the movement of the frog is more to other types of waves, and less to the vortices. How these frogs are able to produce enough thrust to leave the water is likely due to the paddle-like shape of their feet, their elastic, energy storing tendons and muscle fascia, powerful muscle contractions resulting in a land leap applied in water.</p>

Identiferoai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:1571873
Date30 January 2015
CreatorsWilkinson, Kit C.
PublisherNorthern Arizona University
Source SetsProQuest.com
LanguageEnglish
Detected LanguageEnglish
Typethesis

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