whale 10 hours | shark n whale Whale Whales are a widely distributed and diverse group of fully marine placental marine mammals. They are simply an informal grouping within the infraorder Cetacea, usually excluding dolphins and porpoises. Whales, dolphins and porpoises belong to the order Cetartiodactyla with even-toed ungulates and their closest living relatives are the hippopotamuses, having diverged about 40 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have split besides around 34 million years ago. The whales comprise 8-10 extant families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy proper whale), Eschrichtiidae (the grey whale), Monodontidae (belugas and narwhals), Physeteridae (the semen whale), Kogiidae (the little and pygmy sperm whale), and Ziphiidae (the beaked whales). Whales are creatures of the open ...