There are currently 49 known species of dolphins and porpoises, which are divided into six families:- The oceanic dolphin family is the largest, and includes 38 species such as afalins, killer whales, and grinds.
- The porpoise family has 7 species, including the common porpoise and the rare vaquita.
- The remaining 4 families belong to river dolphins, with each family including only one species, such as the Indian river dolphin or the Amazonian bottlenose dolphin.
These animals differ in lifestyle, habitat and anatomical features, but all of them are united by high sociality and a developed ability to communicate.