Scientists Discover Reason Behind Ear Canal In Chinese Frog: Ultrasonic Communication

... A rare frog that lives in rushing streams and waterfalls of east-central China is able to make itself heard above the roar of flowing water by communicating ultrasonically, says new research funded in part by the National Institute on Deafness and Other Communication Disorders. The research may provide a clue into why humans and other animals also have ear canals: to hear high-frequency sounds. ...