Whales are fully aquatic, open-ocean creatures: they can feed, mate, give birth, suckle and raise their young at sea.
Whales consist of eight extant families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), Eschrichtiidae (the grey whale), Monodontidae (belugas and narwhals), Physeteridae (the sperm whale), Kogiidae (the dwarf and pygmy sperm whale), and Ziphiidae (the beaked whales). The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. They are an informal grouping within the infraorder Cetacea, which usually excludes dolphins and porpoises. Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. Superfamily Inioidea (South American river dolphins).Superfamily Platanistoidea (Indian river dolphins).Family Delphinidae (dolphins and porpoises).Superfamily Physeteroidea (sperm whales)Ĭladistically included but traditionally excluded taxa.
