Why do dolphins make so many sounds?

Dolphins make whistle-like sounds to them keep in contact and communicate with each other as they travel and feed. Dolphins “echolocate” to scan their surroundings or to find food. They direct “clicks” into the surrounding water and the clicks rebound off solid objects (like logs, fish, and boats) and echo back to the dolphins. The dolphins then listen for the strength of the rebounding (returning) clicks to identify what the object is and its distance it is from them. Dolphins create all of these whistles and clicks in the there nasal passages just below their blowhole, and scientist believe the sounds may be received by fat deposits in the lower jaw which send vibrations of the echo to the middle ear and brain for processing.