Dolphins are marine mammals nearly related to whales and porpoises. There are almost forty species of dolphins. They vary in size from 1.2 m (4 ft) and 40 kg (90 lb) and up to 9.5 m (30 ft) and 10 tonnes (9.8 long tons).
Dolphins are sights to see. You can only watch them at particular places because vast area is needed and thousands of liters of water is necessary to fill a huge pool. This website is interesting to browse if you want to see some tricks dolphins do.