Neuroscience For Kids

Chinese Frogs Communicate With Ultrasonic Calls
June 5, 2006

Bats, dolphins and some rodents use ultrasonic sounds to communicate. You can now add another animal to this list: the concave-eared torrent frog (Amolops tormotus), the first non-mammalian species found to communicate using ultrasonic sounds.

The A. tormotus is a small frog that lives along fast-flowing streams in China. Researchers found that five of eight male frogs responded when they heard the ultrasonic call of another frog. Recordings from the midbrain of the frogs showed that nerve cells also responded to sounds in the ultrasonic range.

What makes these frogs different from other frogs and why can they hear ultrasonic frequencies? The scientists suggest that A. tormotus has three characteristics that allow it to hear in the ultrasonic range:

• An ear canal; most other frogs do not have ear canals
• Small bones (the ossicles) in the middle ear
• A very thin eardrum.

These characteristics allow the ossicles and eardrum to vibrate at very high frequencies and to transmit this information to the inner ear. The ability of these frogs to use ultrasonic calls may permit these animals to communicate over the loud, low frequency noises (such as splashing water) in their environment. This discovery may help scientists develop new methods to improve hearing in people who work or live in noisy places.

References and more information about hearing, see:

• Feng, A.S., Narins, P.M., Xu, C-H., Lin, W-Y., Yu, Z-L., Qiu, Q., Xu, Z-M., and Shen, J-X., Ultrasonic communication in frogs, Nature, 440:333-336, 2006.
• The Ear - from Neuroscience for Kids
• Hearing - from Neuroscience for Kids

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