Hearing enables us to identify events from the sounds they make. Because sound travels a long way, we can identify events at a distance. Because sound travels rapidly we can identify events almost as soon as they occur. And because sound travels around corners we can identify events even when the objects involved cannot be seen.. One of the roles of hearing is that of watchdog. It works when we are not looking. It works when our eyes are closed. And it even works when we are asleep. During evolution, the survival advantages of such a sense are obvious. Many animals have further capitalized on...