Sci-Tech

Holy bat-battling behavior! Hungry bats jam each other's sonar

Real-life "batmen" discover that when it comes to competing for food at dinnertime, it's a bat-blast-bat world out there.

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It's estimated that roosts of millions of Mexican free-tailed bats can devour 250 tons of insects per night. But competition is fierce. Nickolay Hristov

Imagine this ...

You're a bat. You're hungry. You pick up a nice juicy moth on your inbuilt echolocation system. You head towards it with dreams of a full belly and dessert (maybe a nice mosquito?) in your head. Then -- blamo! You're hit with a sonic shock wave from just above you that scrambles your sonar. You miss the moth but recover just in time to see another bat gobble it down.

Researchers Aaron Corcoran from the University of Maryland and William Conner from Wake Forest University have recently uncovered exactly this scenario amongst Mexican free-tailed bats in the Southwest.

The real-life "batmen" used super-sensitive cameras and an array of ultrasonic microphones to observe bat behavior at the American Museum of Natural History's Southwestern Research Station in Arizona (and in a high school parking lot in Animas, New Mexico). What they found was that one bat would throw another off course as it was going for an insect by sending out a signal that scrambles its sonar.

"The bats often take turns jamming each other until one of them gives up," said a release about the research published Thursday in Science Daily.

In a second experiment, the researchers hung a moth from a fishing line to lure bats and then tried to throw the bats off course by playing the jamming signal through a set of speakers. They were successful as long as they played the sound at exactly the right moment -- something Mexican free-tailed bats seem to have a natural ability to do.

While Corcoran has done previous work showing that tiger moths use sonar jamming as a defensive mechanism to thwart bats, Conner said that it's unknown if other bat types or even other animals that use echolocation (like dolphins) employ the same sonar-jamming strategy when competing for food.

"This is the first study to show that bats actively jam the echolocation of other bats, and it increases the number of known functions of bat sounds to three: echolocation, communication, and acoustic interference," Corcoran said in a statement.

The research detailing the bat-battling behavior has just been published in the journal Science.