 The sperm whale belongs to the order Cetartiodactyla , the order containing all cetaceans and even @-@ toed ungulates . It is a member of the unranked clade Cetacea , with all the whales , dolphins , and porpoises , and further classified into Odontoceti , containing all the toothed whales and dolphins . It is the sole extant species of its genus , Physeter , in the family Physeteridae . Two species of the related extant genus Kogia , the pygmy sperm whale Kogia breviceps and the dwarf sperm whale K. simus , are placed either in this family or in the family Kogiidae . In some taxonomic schemes the families Kogiidae and Physeteridae are combined as the superfamily Physeteroidea ( see the separate entry on the sperm whale family ) . 
