The order Cetacea includes whales, dolphins, and porpoises. It has just over eighty living species, divided into the suborders Odontoceti (the toothed whales, including dolphins and porpoises) and Mysticeti (the baleen whales). In addition, numerous species of extinct cetaceans exist, but they are not listed here. This list contains only the known, extant cetacean species including several recent discoveries (the Baiji is also included though it is believed to have gone extinct in 2006).
Cetaceans are aquatic mammals characterised by having a fusiform (streamlined) body shape, paddle-shaped front limbs and vestigial hind limbs. The tail has been flattened into a fluke to aid propulsion.