Key to the Rodentia
           
 
 Tail sparsely haired, scaly and not distinctly bicolored; fur harsh, grayish brown; underparts grayish white; molars with cusps in two rows directly opposite one another (Fig. 56a)
   
 Tail close-haired, scales inconspicuous; fur soft; molars with cusps in two rows alternating, not opposite (Fig. 56b)
 
           
Artiodactyla
 - 
Carnivora
 - 
Chiroptera
 - 
Didelphimorphia
 - 
Insectivora
 - 
Lagomorpha
 - 
Rodentia
 - 
Xenarthra
Scientific Names - Common Names