Cetacea

The order Cetacea are marine mammals that live in oceans, seas and even a few rivers around the world. Whales, dolphins and porpoises are part of this group. These common names refer to size: whales are the largest, porpoises the smallest. How and what they eat is a better guide to their relationships. The study of cetaceans is called cetology.

Cetaceans are ocean creatures without toes, but are classified in the related order Cetartiodactyla because their ancestors were even toed ungulates.

 Taxonomy 
 Infraorder Cetacea
 Parvorder Mysticeti: Baleen whales
 Family Balaenidae: Right whales and Bowhead whale
 Bowhead whale, Balaena mysticetus
 Genus Eubalaena: Right whales
 North Atlantic right whale, Eubalaena glacialis
 North Pacific right whale, Eubalaena japonica
 Southern right whale, Eubalaena australis
 Family Balaenopteridae: Rorquals
 Genus Balaenoptera
 Blue whale, Balaenoptera musculus
 Fin whale, Balaenoptera physalus
 Humpback whale, Megaptera novaeangliae
 Family Eschrichtiidae
 Gray whale, Eschrichtius robustus
 Family Neobalaenidae
 Pygmy right whale, Caperea marginata
 Suborder Odontoceti: Toothed whales
 Family Delphinidae: Oceanic dolphins
 Family Phocoenidae: Porpoises
 Family Monodontidae
 Beluga, Delphinapterus leucas
 Narwhal, Monodon monoceros
 Family Physeteridae: Sperm whales
 Sperm whale, Physeter catodon
 Dwarf sperm whale, Kogia sima
 Pygmy sperm whale, Kogia breviceps
 Family Ziphiidae
 Cuvier's beaked whale, Ziphia cavirostris
 Superfamily Platanistoidea: River dolphins