no teeth; instead, they have plates of baleen, fringe-like structures that enable them to expel the huge mouthfuls of water they take in while retaining the krill and plankton they feed on. Because their heads are enormous--making up as much as 40% of their total body mass--and they have throat pleats that enable them to expand their mouths, they are able to take huge quantities of water into their mouth at a time. Baleen whales also have a well-developed sense of smell.

Toothed