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Though it’s fair to say that male crickets sing to attract females, it’s more accurate to say that they stridulate. Stridulation is the production of sound by rubbing body parts together, and it’s widespread in crickets, grasshoppers and katydids.

Typically, one part of the body functions as a scraper with a ridge or bump that can be dragged across a body part with fine ridges that functions as the file. Crickets and katydids rub the scraper on one wing against the file on the other wing, but in grasshoppers, the hind leg is the scraper and is rubbed along the forewing.

Lots of animals stridulate, and not all the noise they are making is to attract mates. The sounds can function as alarm calls, as threat displays to potential predators, as a way to reunite with family members in a social group, or serve as territorial defense.

Stridulation is most common among insects. Many beetles stridulate, including bess beetles, long-horned beetles, weevils, bark beetles, tiger beetles, stag beetles and scarab beetles. Other insects that stridulate include velvet ants, assassin bugs, leaf bugs and water boatmen. Arthropods that are not insects also stridulate. For example, Goliath tarantulas rub the bristles on their legs together to make a loud hissing sound that functions as a warning signal to potential predators and can be heard 15 feet away.

Though arthropods, specifically insects, are the world’s best known stridulators, many other animals produce sound by rubbing body parts together, including snakes. Several species of vipers stridulate as a threat display. They fold into tight C-shaped coils and rub the parallel parts of the body along each other. The sizzling sound they make is reminiscent of water drops in a frying pan.

Male club-winged manakins (a South American bird species that lives in the Andean cloud forests of Colombia and Ecuador) stridulate to court females. They use the club-shaped feathers of their wings to produce a noise that sounds something like a violin (though certainly, to be honest, not one being played by a virtuoso). The male’s feathers rub against each other while moving at a rate exceeding 100 cycles per second, which is more than twice as fast as hummingbirds can flap their wings.

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The only mammal known to stridulate is the streaked tenrec of Madagascar. It looks like a hedgehog crossed with a shrew and weighs less than half a pound. These animals have specialized quills along their back which they rub together to produce ultrasonic calls too high for humans to hear. (They were detected and recorded with bat detectors.) It is believed that tenrecs use this sound to communicate with other members of their family groups when they are foraging together, which they do at night. Another possibility is that these sounds function as warning calls to predators.

Admiration, or perhaps envy, of the musical ability of all these animals may explain the decision by composer and flutist Nicole Chamberlain’s to write “Stridulation for Two Flutes and Cello”, which premiered in 2014.

Karen B. London, Ph.D. is a Certified Applied Animal Behaviorist, Certified Professional Dog Trainer, author, and an Adjunct Faculty in NAU’s Department of Biological Sciences.


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