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 Ancodonta Matthew, 1929 [monotypic]
                 Family Hippopotamidae Gray, 1821 - hippopotamuses