Dolphins communicate by producing a range of vocal signals and ultrasonic pulses. They will whistle in social situations, when separated from friends, and when excited, happy or panicked. Pulsed sounds known as clicks are not only used to communicate with one another, but also for sonar purposes, allowing them to “see” through sound the same way bats do. Having produced a click, a dolphin will wait for the echo to help him form a mental image of objects located in its environment.