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HOW do chameleons manage to grab big creatures like birds using just their
tongues? A Belgian scientist has come up with the answer: chameleons suck.

Many reptiles use their tongues to capture prey, and most rely on their
tongue鈥檚 rough surface and sticky coating of mucus to get a good grip on a
target. But this only works for small prey such as insects.

Chameleons are known to feed on larger animals such as lizards and birds. But
to catch animals of this size, they would need an unfeasibly big tongue with a
huge surface. 鈥淚t鈥檚 going to be so big, it鈥檚 going to be bigger than their
head,鈥� says Anthony Herrel at the University of Antwerp. 鈥淚t made us think
there鈥檚 something weird going on here.鈥�

To find out the chameleon鈥檚 secret, Herrel collaborated with researchers at
Northern Arizona University in Flagstaff to film them feeding. Head-on shots
taken using high-speed video cameras showed the tongue changing shape just
before making contact with the prey.

鈥淎 couple of milliseconds before the tongue hits, the end forms a kind of
suction pad. It looks like a bit like a baseball glove,鈥� says Herrel. Subsequent
frames from Herrel鈥檚 video showed that once the suction cup had stuck to the
prey, muscles in the tongue contracted to draw the cup back, increasing the
suction.

To check his finding, Herrel anaesthetised chameleons and cut the nerves to
the muscles used to form the suction cup. When these chameleons then tried to
feed, their tongues simply knocked the prey out of the way instead of grabbing
it.

Kurt Schwenk, an evolutionary biologist who studies reptile tongues at the
University of Connecticut in Storrs, is impressed by the unusual trick. He wants
to check out whether any other lizards use a similar 鈥渇lick `n鈥� suck鈥� technique.