There are 42 species of dolphins in the world. There are 38 species of marine dolphins and four species of river dolphins. The normal habitat for dolphins is saltwater, but some do live in freshwater. Dolphins are generally found in the shallow coastal waters of warm locations.
The most commonly known dolphin is the bottlenose. This is the species most often seen in aquariums, and these dolphins are very intelligent and easy to train. The striped dolphin is believed to have the highest population, while the spinner dolphin has amazing acrobatic ability. In 2011, a new dolphin species, the Burrunan dolphin, was discovered near Australia.