Friendly Whale

Cetaceans are divided into two suborders:
- The largest suborder, Mysticeti (baleen whales) are characterized by baleen, a sieve-like structure in the upper jaw made of keratin, which it uses to filter plankton from the water.
- Odontoceti (toothed whales) bear sharp teeth for hunting. Odontoceti also include dolphins and porpoises.
Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippopotamuses. Whales are the hippopotamus's closest living relatives.