Cetacea
First, it must be said: Dolphins are also whales!
Whales (Cetacea) are an order in the class of mammals, comprising about 90 species. Dolphins (Delphinidae) are a family within the order of whales.
Whales are divided into two suborders. Besides the baleen whales (Mysticeti), which primarily feed by filtering plankton and small schooling fish, there are the predatory toothed whales (Odontoceti).