Some Moths Escape Bats By Jamming Sonar For over 50 million years, bats and moths have been engaged in an evolutionary arms race. A study in the journal Science identifies another weapon in the moth arsenal: the ability to jam bat sonar. Aaron Corcoran, of Wake Forest University, explains the research.
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Some Moths Escape Bats By Jamming Sonar

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Some Moths Escape Bats By Jamming Sonar

Some Moths Escape Bats By Jamming Sonar

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Up next, Flora Lichtman is here with our Video Pick of the Week. Hi, Flora.


FLATOW: What have we got for us this week?

LICHTMAN: This week, we have a classic tale of two foes trying to outsmart each other, but in the animal kingdom.


LICHTMAN: It's the story, the 50 million-year-old story I should say.

FLATOW: That's a year ago.

(Soundbite of laughter)


LICHTMAN: Yeah, give or take…

FLATOW: Right.

LICHTMAN: …of bats and moths.

FLATOW: Because bats like to eat moths.

LICHTMAN: Yes. So for bats, moths are kind of like a tasty snack…

FLATOW: Mm-hmm.

LICHTMAN: …so they've spent the last, you know, millions of years refining their bat - their moth-catching technique.

FLATOW: Mm-hmm.

LICHTMAN: And moths, in turn, don't want to be eaten.

FLATOW: Of course not.

LICHTMAN: Of course not.

FLATOW: Hate it when that happens.

(Soundbite of laughter)

LICHTMAN: And so they have been working on escaping bats.

FLATOW: And bats normally locate moths, what, through the sound?

LICHTMAN: That's right. So bats echolocate. They send out these high-pitched, high-frequency sounds, and they listen for the echoes. And based on when these echoes come back, they can create an acoustic picture of what's around them. And that's how they find the moths. Just like sonar…

FLATOW: Right. Right.

LICHTMAN: …you know, familiar with "Hunt for Red October."

FLATOW: Right. But - so the bats have found a way to jam the sonar?

LICHTMAN: That's just…

FLATOW: The moths have found a way to jam the bats' sonar.

LICHTMAN: It makes perfect sense, right?


LICHTMAN: Your predator comes after you…

(Soundbite of laughter)

LICHTMAN: …using sonar. So what do you do? You figure out a way to jam it.

FLATOW: And that's…

LICHTMAN: And we're about to hear it.

(Soundbite of bat sonar call)

FLATOW: Wow. Wow. That would send me away.

(Soundbite of laughter)

LICHTMAN: Yes. So it's little bit scary. So the first clicks you hear - maybe we can hear it again. But the first couple clicks are the - that's the bat echolocating.

FLATOW: Mm-hmm.

LICHTMAN: And the sound was actually been slowed down. We wouldn't be able to hear it if it weren't.

FLATOW: So on our Video Pick of the Week, you actually have some photos, some video.

LICHTMAN: Yes. The researchers at Wake Forest, Aaron Corcoran and Dr. Conner…

FLATOW: Mm-hmm.

LICHTMAN: …were able to capture these bat attacks.

FLATOW: Mm-hmm. And Aaron Corcoran is right - is with us on the phone right now. Hi there, Dr. Corcoran.

Dr. AARON CORCORAN (Ph.D. student, Wake Forest University): Hello, Ira.

FLATOW: Hi there. You - I saw the video that Flora made. And it shows you that bats are - they're bamboozled, is the way I would put it, by the interference by these moths.

Dr. CORCORAN: They really are. They really are. They had a extremely difficult time catching these moths that were making a whole lot of sound. And then when we silenced the moths and made it so that they couldn't make the sound, they captured the moths almost every time.

FLATOW: Wow. And the way they capture them was fascinating, Flora, in the video.

LICHTMAN: Yeah. Absolutely. Maybe you can set the scene for us. Explain what this lab setup is like.

Dr. CORCORAN: Sure. It's a medium-sized room. And on the edges of the room, the ceiling and floors are sound-absorbent foam, so as the bats will fly in there so that there's not a whole lot of echo. And then we tether an individual moth on a monofilament line.

LICHTMAN: Like fishing line, is that?

Dr. CORCORAN: On a fishing line, yeah. And then we let an individual bat fly in the room and make up to five attacks on the moth and then we see what happened.

LICHTMAN: And what happened…

Dr. CORCORAN: Recorded all of this in infrared video and the ultrasound.

LICHTMAN: And what happened when you put these clicking moths on the fishing line?

Dr. CORCORAN: When we put the clicking moths on the fishing line, first the bats had a really hard time catching them. And second, the bats showed really abnormal echolocation behavior.

FLATOW: So they were baffled by the moths.

Dr. CORCORAN: They were baffled by them. They kept trying to attack them, kept trying to capture them, but they had very little success in doing so.

LICHTMAN: And how do you know that the sound that the moth is making in response is actually jamming the sonar and not, you know, doing something else like scaring the bat?

Dr. CORCORAN: Right. We had to rule out a couple of other hypotheses that were legitimate. The first of which is the startle hypothesis, just that the sounds are very loud and takes the bat off guard. To eliminate that hypothesis, we tested the bats over a series of days. And if the bats were being startled, we would expect that they would habituate to the sounds after maybe two or three days. But that's not what happened. The defense was effective on the first day and all the way through the seventh day.

FLATOW: Wow. And this is fascinating video. You can watch Dr. Corcoran's video on our SCIFRI Pick of the Week on our Web site at And you can not only watch the bats evade it, but you can watch how bats actually capture the moths. It's very fascinating. Thank you for taking time with us, Dr. Corcoran.

Dr. CORCORAN: Okay. Thank you for having me on.

FLATOW: Dr. Aaron Corcoran is a biology Ph.D. student at Wake Forrest University. And thank you, Flora.


FLATOW: That's Flora's SCIFRI Pick of the Week on our Web site at It's fascinating watching these bats trying to catch the moth and watching how - when they do, how they use their wings and their tails and all kinds of stuff.

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