Tympole

Tympole live in large groups known as “circles.” The growths on either side of their heads can vibrate quickly in order to produce ultrasonic waves. These waves, though imperceptible to humans, are how Tympole communicate with one another. When threatened, a Tympole will emit a distinctive pattern and frequency of sound that only other Tympole can hear; once the rest of the circle hears the warning, they will all begin to produce the same sound. The circle will then, as a group.