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North American walnut sphinx caterpillars tend to do moreÌýchewing than chatting,Ìýbut when they’re an open beak away from becoming lunch, they’ll let out screams that shakeÌýthem to their very core—and leaveÌýtheir predators shook, too. TheÌý contracts its body muscles to lets out an imitation seet call—a warning cry some songbirds emit when facing imminent danger such as a hawk. The theory is that this ÌýintoÌýstoppingÌýtheir attacks and flyingÌýaway, ensuring the safety of the otherwise vulnerable insect.

To test the success of the caterpillar's cries, Jessica Lindsay, an undergraduate student at the University of Washington, set up an experiment to analyze the birds' responses. After recording the insect'sÌýsounds—which can be as loud as a freight train from 50 feet away—she played them back to wild flocks atÌýfeeders. She thenÌýdid the same withÌýrealÌýseetsÌýfromÌýBlack-capped Chickadees and compared the two sets of reactions.ÌýTurns out, both calls made theÌýwould-be diners dive for cover. Her results, presented atÌýtheÌýÌýin July, wereÌýfirst reported byÌý

An example of a realÌýseetÌýcall from a House Finch:

According to Michael Singer, an , there are caterpillars thatÌý, but this is the first known case of vocal mimicry. When it comes to facing downÌýpredators,Ìýmost species rely on strategies that target a bird's sight, smell, or taste with popular tactics, includingÌýcamouflage, bright coloring, or snake-like getups, SingerÌýsays. If those deterrents fail, the insects will resort to biting, barfing, or launching themselves off the plant entirely. Still, evenÌýthese methods typically aren’t enough to save the caterpillar from a bird’s appetite. Lindsay's findings, however, indicate that the walnut sphinxÌýhas evolved a smart way toÌýscreamÌýitselfÌýstraight out of a tight situation. That is,Ìýuntil the birds .

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Freebie Alert! Don't be fooled by caterpillars or other mimics. Learn the callsÌýof 821 North American species with theÌýÃÛèÖAPP Bird Guide app.Ìý

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