Sticky mucus is their weapon of choice.
In one swift motion, a chameleon flings its tongue out and snags its prey, which is swiftly pulled back into the mouth of its camouflaged predator.
Reporting in the journal Nature Physics, researchers showed that the mucus on the tip of a chameleon’s tongue is 400 times thicker than human saliva. It is this glue that allows the chameleon to capture prey weighing up to 30 percent of their own body weight and to drag the heavy prey into their mouths at great speeds.
To explore the properties of this honey-like adhesive, the researchers dangled a prey item in front of a chameleon to provoke a shoot of the tongue. A glass microscope slide was strategically placed in front of the prey so that the chameleon’s tongue would scrape the slide, leaving behind a trail of sticky mucus.
The researchers released small steel balls down the mucus-coated slide, which was mounted at an angle. The more adhesive the mucus, the quicker it was expected to stop the balls.
It was only when the balls were rolling rapidly that the mucus was very sticky — this is equivalent to what happens when the tongue extends and retracts at high speeds to catch a prey item.
In addition to being covered with thick mucus, chameleons’ tongues are wider at the tip. This shape increases the surface area available for gripping and the strength of the hold that the tongue may exert on prey.
By unfurling their wide-tipped tongues and releasing their natural glue, chameleons have the luxury of being able to pick from a wide selection of prey ranging from tiny insects to the occasional bird, lizard, or mammal.