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By. John J. Socha

Becoming airborne without legs: the kinematics of take-off in a flying snake, Chrysopelea paradisi. By. John J. Socha. INTRODUCTION. There are many animals that can “fly”: snakes, squirrels, lizards, and frogs. Powered-take off Locomotor challenge

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By. John J. Socha

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  1. Becoming airborne without legs: the kinematics of take-off in a flying snake, Chrysopeleaparadisi By. John J. Socha

  2. INTRODUCTION • There are many animals that can “fly”: snakes, squirrels, lizards, and frogs. • Powered-take off • Locomotor challenge • Understanding different take-off behaviors may be key to understanding the evolution of flight and aerial locomotion

  3. Supporting Papers: • Bishop, K. L. (2006). The relationship between 3-D kinematics and gliding performance in the southern flying squirrel, Glaucomys volans. J. Exp. Biol. 209, 689-701. • Socha, J. J. (2002a). Gliding flight in the paradise tree snake. Nature 418, 603-604.

  4. BIG QUESTION • How does a limbless animal initiate aerial locomotion from a high perch?

  5. OBJECTIVES • 1) describe the kinematics of take-off in the paradise tree snake, Chrysopeleaparadisi. • 2) determine the effect of different take-offs on overall performance.

  6. MATERIALS AND METHODS • 21 wild-caught paradise tree snakes • 3.0-82.7grams • 31.0-86.5cm SVL • Snakes were launched off a tower in open field. • Marked • Placed on branch by hand • 239 take-offs in total were recorded • Variables that were analyzed: take-off duration, vertical height gained, horizontal range, velocity and acceleration.

  7. TAKE-OFFS • Anchored J-loop take-off • Sliding J-loop take-off • Dive and fall take-offs • Slow step-by-step Quick turn Long Glide Side view of J-loop take-off Rear view of J-loop take-off If above don’t work…

  8. RESULTS • 2 distinct modes of take-off: looped and non-looped • Looped (Fig. 1 and Fig. 2A,B)**** Predominantly used. 78% of the time (187/239 trials).

  9. RESULTS • Non-looped (Fig. 2C) include a “dive” and “fall”

  10. RESULTS • Socha (2002), Nature 418: 603-604.

  11. RESULTS • Types of branch grips

  12. RESULTS • Velocity and acceleration

  13. RESULTS • Head angles during take-offs.

  14. RESULTS • Differences between looped take-offs and non-looped take-offs and differences in anchored J-loop take-offs and sliding J-loop take offs

  15. CONCLUSION • This study enables us to see how flying snakes can become airborne from a horizontal perch. • These snakes have overcome evolutionary limitations imposed by lack of limbs in order to jump into the air. • This study opened new doors for hypotheses such as form, function and ecology in relation to the evolution of flight in gliding animals.

  16. FURTHER QUESTIONS • Are there kinematic differences between take-offs from horizontal and vertical substrates? • What kind of physical characteristics of the branch affect take-offs? • How do these snakes take-off in the wild?

  17. DISCUSSION 1) Why would snakes develop this mode of locomotion? What are some adaptive advantages to this mode of locomotion? 2) What do flying squirrels, lizards and snakes have in common in their flight mechanisms? How does this develop our understanding of the evolution of flight in general? 3) What would motivate a snake to take off in the wild? 4) What physiological differences are there between flying squirrels and flying snakes?

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