Class [Mammalia] Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Family Sciuridae Batsch, 1788 - squirrels, chipmunks, marmots, and prairie dogs
       1 Subfamily Sciurinae Batsch, 1788 - tree and ground squirrels
       2 Subfamily Pteromyinae Brandt, 1855 - flying squirrels