Chameleon's tongue-lashing technique analyzed

Fri Jan 8, 2016 8:16am EST
 
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By Matthew Stock

Found in Tanzania's Usambara Mountains, Rhampholeon spinosus is a species of chameleon small enough to fit on a human thumb. But what it lacks in size it more than makes up for in the speed and power of its tongue.

Biologist Christopher V. Anderson, from Brown University's Department of Ecology and Evolutionary Biology, studied the feeding technique of 20 species to test his theory that smaller chameleons could pack a more powerful punch. He based his hypothesis on recent anatomical studies that found that smaller chameleons have a proportionally larger tongue structure than bigger chameleons, and so could have relatively longer tongue projection distances.

The study was carried out using a high-speed camera shooting at 3,000 frames per second (fps). The video shows the rapid recoil of elastic tissues in the chameleon's tongue when it strikes to catch an insect.

Published in scientific journal Nature, experiments found that small chameleons are able to project their tongues by 2.5 body lengths. The power of their tongue strikes compared to bigger species may be down to evolution, according to the study.

"Small chameleon species may be under pressure to increase the effectiveness of their feeding apparatus in order to mitigate metabolic scaling constraints," writes Anderson.