420 FOUR-FOOTED AMERICANS 



Tamias — Ground Squirrels — Chipmunks 

 Smnller and lighter than the true squirrels, with the back 

 striped. 



Chipmunk . . Tamias striatus. 



Length of body, 6 inches ; tail, 4| inclies. 



Arctomys — Woodchucks 

 V\\t\\ heav)' body, short ears and tail ; cheek pouches im- 

 perfect or none. Gnawing teeth very broad and strong. 



Woodchuck . . Arctomys monax. 



Length of body, 14^ inches ; tail, 7 inches. 



Cynomys — Prairie Dogs 

 Intermediate in size lietween AY(»)di;hueks and Spermo- 

 philes. Short ears; small cheek pouches; five clawed front 

 feet. Live in burrows in large communities and feed on 

 prairie grass, 



Prairie Dog . . . Cynomys ludovicianus. 



Length of body, 13 inches ; tail, 4 inches. 



Spermophilus — Spermophiles 



Rather small and slender, tail variable. Ample cheek 

 pouches ; four front toes. Belong to prairies and dry, open 

 plains ; live in deep burrows and store up food for winter use. 

 Rock Spermophile . . . Spermophilus grammurus. 



Lengtli of body, 18 inches ; tail, U inches. 



Striped Spermophile . Spermophilus tridecemlineaius. 



Length of body, 7 inches ; tail, 4J inches. 



I'lEAVEl; FA:\riLY 

 Castcridse 



(Nnnilioi- of Nnrth American Species, One) 



Heavy skull; powerful teeth; strong front claws. Tail 

 flat and tongue-like. The best builder among ^lammals. 



Beaver .... Castor canadensis. 



Length ot body, 2 feet ; tail, 10 inches. 



