The Cold Blooded News
The Newsletter of the Colorado Herpetological Society
Volume 28, Number 6; June, 2001
This hitherto secret maneuver, over in the blink of an eye, gives chameleons a considerable advantage over other reptiles that rely merely on a sticky tongue to ensnare their prey. The secret was discovered after researchers at Northern Arizona University became suspicious when relatively large lizards disappeared from a cage they shared with chameleons. We realized the chameleons must have been picking off the other lizards in the cage," said Jay Meyers, one of the research team. "It shouldn't have been happening. How could something with just a sticky tongue catch something so large? "We decided to get a high-speed video camera and find out." The camera, shooting at 250 frames a second, caught the chameleons contorting the tips of their tongues milliseconds before impact. The tip would then form a suction seal around the target, exerting such force that the prey was helpless to resist being dragged into the chameleon's mouth. "It was an amazing display of control and speed," Meyers said. "The seal looks a bit like a baseball glove, with the prey as the ball. Once the seal is formed it acts a bit like the suction cup at the tip of a child's toy arrow and pulls the prey back. The whole thing happens really quickly. It only takes about half a second for the chameleon to shoot its tongue out almost six inches, form a seal around the prey and drag it back to its mouth." Meyers, who worked with Anthony Herrel, an evolutionary biologist at the University of Antwerp in Belgium, believes that the maneuver involves a pair of muscles on either side of the chameleon's tongue working to roll the tip inwards. It seems vital to the hunting success of all the species of chameleons (Chameleo) they studied.
When small cuts were made in the nerves controlling the muscles making the suction pad, the chameleons' tongues just knocked harmlessly against their prey instead of grabbing it. Fortunately for the chameleons, their vital nerves grew back. The hunting trick now seems likely to rank with the chameleon's ability to change color in the space of 10 seconds in response to their mood changes or the need for camouflage. "It's pretty wild," said Meyers. "You don't even see any other living lizards doing anything close.
This is a unique thing for lizards, and probably vertebrates in general. We have seen nothing else that does it. It's unknown elsewhere in the animal kingdom."
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