Class Mammalia Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Suborder Sciurognathi (Tullberg, 1899) see Suborder Sciuromorpha Brandt, 1855
       Family Castoridae Batsch, 1788 - beavers
         Genus Castor Linnaeus, 1758 - beavers
           1 Castor canadensis Kuhl, 1820 - American beaver
           2 Castor fiber Linnaeus, 1758 - Eurasian beaver