The message which is carried is not, however, always connected with the hearing sense. For instance, a certain kind of tadpole can tell the depth of the water it is swimming in by the pitch of a tone which is produced by its own lungs.

• 但是被承载的信息并不总是与听觉相连。举个例子，有一种蝌蚪能感知它所游泳之处水的深度，它是通过某种自己肺部产生的声音的音调来判定的。