Female Frogs Can Tune Out Unwanted Mating Calls With 'Noise-Cancelling' Lungs

Updated September 4, 2021

I have to admit that I never really "got" nightclubs. Dancing is fun and everything but I can do that in places that aren't always uncomfortably hot and where I don't have to pay over 10 bucks per drink.

But if there's one thing that I understand the least about clubs, it's the idea of meeting people in a place where you are guaranteed to struggle to hear them. I guess screaming "what?" over and over again just isn't my idea of a good time.

And based on the findings from some fascinating new research that seems to be a similar concern for frogs. Fortunately for them, it seems they've got a solution already built into them.

To understand what a research team led by Norman Lee discovered about frogs, we must first familiarize ourselves with how frogs hear.

Reddit | OleBenjaminLay

As the team explained in an article published in the journal Current Biology, frogs' lungs resonate to sound because they're "large air-filled cavities overlain by a relatively thin body wall."

Much like with the resonance chamber of a musical instrument, the size and shape of these lungs influence what sound frequencies are carried to the ears. It's just that in frogs, the lungs transmit those sounds to the ears.

It also helps to appreciate how oppressively noisy a frog's breeding season tends to be.

Wikimedia Commons | Piet Spaans

As Lee's team outlined, the most frequent reason a frog has to ribbit is the production of mating calls that both attract mates and ward off rivals.

From the perspective of a female frog, mating involves experiencing a barrage of loud and constant noise from hundreds of males of multiple frog species that can exceed 100 decibels.

With that in mind, researchers sought to determine how female frogs were able to overcome this "cocktail party problem" and pick a suitable mating call out from the din.

Reddit | souredmilks

Although they knew the extent to which the American green treefrogs they examined would inflate their lungs would control this noise to some degree, they weren't sure whether this would amplify desired calls or mute undesired noise.

Noise in this case can be defined as both non-call background noise and the calls from frogs of other species.

Once they ruled out that any amplication was going on, Lee's team was able to drill down into how the "noise-cancelling" effect of a frog's lungs works.

Reddit | honwing

What they found was that when the frog's lungs were sufficiently inflated, she was able to cancel out any frequencies that fell beyond the range of 1400 to 2200 Hz.

The researchers described this as "a restricted but biologically important frequency range" because it not only restricted her hearing to mating calls but also filtered out those outside of the frequency range specified.

This works because larger frogs, for example, produce lower frequencies both by having larger lungs and larger vocal folds.

Reddit | OofButInMinecraft

With this finding, Lee's team believes they may have not only solved a problem that has puzzled other researchers examining vertebrate hearing for a long time, but also unlocked key information that could potentially apply to 7,200 other species of frog.

They also had the effect of making us wish we were frogs whenever things get too noisy.

h/t: Current Biology

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