Just as dogs growl before they bite, some caterpillars click their jaws to warn potential predators they are about to turn nasty. This is the first time caterpillars have been shown to emit warning sounds.
When disturbed, caterpillars of the silk moth Antheraea polyphemus emit a series of audible clicks – about as loud as lightly snapping your fingernails. They do so to warn predators they are about to puke, something the predators find repugnant.
Sarah Brown of Carleton University in Ottawa, Canada, and her colleagues showed that the caterpillars clicked in response to attack by either domestic chickens or a…
