Catapult Chameleon Tongue

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Catapult chameleon tongue "fires the imagination" of zoologists, Jurrian de Groot of Leiden University and Johan van Leeuwen of Wageningen University, Netherlands, according to scienceNOW, 8 Mar 2004. De Groot and van Leeuwen have discovered a previously unknown mechanism that makes chameleons' tongues so quick and powerful. The chameleon thrusts out its tongue using an accelerator muscle wrapped around a core of stiff cartilage embedded in the tongue. After filming chameleons catching prey using a high speed X-ray technique and calculating the amount of force needed to move the tongue so rapidly, de Groot and van Leeuwen concluded that the accelerator muscle alone was not powerful enough to produce the quick-fire movement chameleons are famous for. They then carefully dissected chameleon tongues and found numerous ’slipper sheaths’ attached to the cartilage core. These contained spirally wound proteins that distorted when the accelerator muscle contracted. The distorted proteins stored energy like a stretched rubber band. During the thrusting movement generated by the accelerator muscle, the sheaths containing them slip off the cartilage core and proteins recoil to their original shape. This makes the sheaths spread out like the tubes of a telescope when it is lengthened. "It is a sort of telescopic catapult," commented van Leeuwen.

Editorial Comment: The mechanisms of telescopes and catapults both took purposeful design and manipulation to make. To combine the two into a useful mechanism involves even more creative design ­ good evidence chameleons were created by a smarter Designer than the human creators of telescopes and catapults. (Ref. chameleon, muscle, design)

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