The sound travels out in waves, hits an object and bounces back. The reflected sound waves are first received by the skull and jaw, then transmitted to the ear. The dolphin assembles the waves into a mental image of what is in the water. By echolocating, dolphins can tell how big something is, which direction it is going, how fast, and what is inside it. Each dolphin has its own special whistle.
Dolphins make so many different sounds that it is possible that they have their own language.
People have tried for many years to figure out whether the communications are really a language and whether humans can interpret it. A group of dolphins sometimes surrounds a school of fish and herds them together. Then the dolphins catch the fish in their mouth and swallow them whole. Dolphins also dive, as deep as 1,700 feet, for food. They can hold their breath for as long as 7 minutes, then they must come up for air.