Dolphins are part of the toothed whale suborder.
There are about 65 different species of toothed whales. Toothed whales, including all dolphins and porpoises, have teeth, only one blowhole (baleen whales have two) and are generally smaller than most baleen whales. The only toothed whale longer than 13 metres is the sperm whale (they can measure up to 18 metres).
Toothed whales are hunters. They find, chase and then capture prey (fish, squid, crabs, starfish, and other ocean creatures) with their teeth. Once captured, the prey is swallowed whole.
Toothed whales find their food using echolocation. It works as a navigation system and can detect objects, such as fish, in the water. The whale sends out signals, called ultrasounds from its nasal passage. The signals bounce or echo off objects, then return to the whale, giving a clear sound-picture of the objects size, shape and location.
Fast Fact :
Despite their names, the long-finned pilot whale and the killer whale or orca, arent really whales, theyre dolphins.