92 VERTEBRATES I MAMMALS. 



Fig /9> which the hunters call " dog- 



towns." Before each hole there 

 is a little mound of earth upon 

 which a Prairie Dog is almost al- 

 ways sitting, on the lookout for 

 intruders, and, on the slightest 

 alarm, dives into its hole, but 

 soon cautiously appears again. 

 It is well known that their holes 



are tnC nome Of the burrOW- 

 ing owls and rattlesnakes, with 

 c. ludovidanus, Baird. whom the dogs seem to live in 



perfect harmony ; but it is more probable that they are 

 intruders who are tolerated from necessity. 



The Short-tailed Prairie Dog, C. Gunnisonii, Baird, is 

 similar to C. ludovicianus. 



The Genus Arctomys Woodchucks is characterized 

 by a large, thick, depressed body, rudimentary cheek- 

 pouches, rudimentary thumb armed with a small flat 

 nail, and naked soles. They pass the winter in a tor- 

 pid state. 



The Woodchuck or Ground Hog, A. monax, Gm., of 

 the Northern States and southward, is fifteen to eighteen 

 inches long to the tail, which is about half as long as the 

 head and body ; color varying from black all over to 

 grizzled above and bright chestnut-red beneath ; the feet 

 always black or dark brown, and the tail generally black. 

 They often commit great havoc in fields of clover, upon 

 which they like to feed. 



The Yellow-footed Marmot, A. flaviventer. Bach., is 

 found in Nebraska. 



The Hoary Marmot, or Whistler, A. pruinosus, Gm., 

 of Northwestern North America, is about the size of the 

 common woodchuck. 



The Alpine Marmot, A. alpinus, Linn., of the high 

 mountains of Europe, immediately below the region of 



