A frog that can hear through its mouth!

By Casey Frye, CCNN Writer

The Gardiner’s Seychelles frog is one of the smallest amphibians in the whole world, as it measures only half an inch long. That’s cute, huh? If I ever had him as a pet, I would probably call him Froggie, or, no, maybe Hopper. I just hope he has his mouth open when I call his name, because according French researchers, that’s how he can hear sounds!

I don’t even know how to begin thinking about that. Is there an ear inside his mouth like a mutant, or is the mouth the actual ear? I’m so confused! Apparently, when researchers encountered the frog, they were just as baffled. In a natural setting, the Gardiner’s Seychelles frog croaks to communicate with other members of its species, so it appeared like they were capable of hearing. However, they don’t have any eardrums, which are needed to conduct sounds to the brain!

Just to be sure he could hear, researchers took the frog into their lab and played recordings of croaking. Sure enough, he replied to the sounds! However, unlike our ears and other frogs that use bones to communicate sounds to the brain, the creature didn’t have any. In fact, they didn’t even have organs or muscles that could either, based on x-ray images.

No ear bones, no ear muscle, no ear organ… hmm? How does he know the other frogs are even croaking?! The mystery was nowhere near being cracked until the scientists had a crazy thought: what if the Gardiner’s Seychelles frog uses its tiny little mouth as an ear? To test their hypothesis, they ran a computer simulation. Believe it or not, the math added up! Apparently the frogs do hear though their tiny mouths! Mystery solved!

I wonder which would work better to clean their ears, a q-tip or a toothbrush…

Featured image courtesy of R. Boistel/CNRS and video courtesy of ESRF.