Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Infraclass Eutheria Gill, 1872
       Magnorder Boreoeutheria Springer & de Jong, 2001
         Superorder Laurasiatheria Waddell, Okada & Hasegawa, 1999
           Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
             Suborder Whippomorpha
               Infraorder Cetacea Brisson, 1762
                 Parvorder Odontoceti Flower, 1867 - toothed whales
                   Superfamily Physteroidea orth. inval. see Superfamily Physeteroidea Gray, 1821
                     1 Family Physeteridae Gray, 1821 - sperm whales
                     2 Family Kogiidae Gill, 1871