A male southern grasshopper mouse sings in Mexico's Chihuahua Desert.
Whistling Caterpillars And 5 More Surprisingly Musical Species
The shrill sound has many purposes in nature, from deterring predators to deepening bonds.
Some people can't whistle at all, much less whistle without lips.
The walnut sphinx caterpillar has no such trouble. When disturbed, say by a predator, these North American insects compress their bodies and squeeze air out of holes in the sides of their bodies, called spiracles. The result is a shrill sound that can last for several seconds.
Now Jayne Yack, a neuroethologist at Carleton University who made the spiracle discovery, has found the high-pitched noises dissuade hungry birds. (Read: "Caterpillars Drum Their Anuses To Find New Friends.")
“There are different hypotheses to explain why a predator would be deterred, and we tested the startle hypothesis: Namely, that the whistle freaks out and frightens the bird so it doesn’t come back,”