List of Illustrations 



FACING PAGE 



Beaver Lodges and a Dam ...... 148 



A Pair of Woodchucks by their Burrow (Arctomys monax) 152 



Woodchuck (Arctomys monax) 154 



Prairie Dogs (Cynomys ludovicianus) . . . . 156 

 Western Spermophile (Spermophilus), photographed in 



Colorado 158 



Say's Spermophile (Spermophilus later alls) . . . 160 



White-tailed Spermophile (Spermophilus leucurus) . . 162 



Young of Columbia Spermophile (Spermophilus cohimbianus) 162 



Say's Spermophile in Snow (Spermophilus later alls) . 164 



Young Prairie Dog (Cynomys ludovicianus), about one-third 



grown 164 



Western Chipmunk (Tamias quadrivitatus) . . . 166 



Chipmunk (Tamias striatus) 168 



Gray Squirrel (Sciurus carolinensis) 170 



Red Squirrels (Sciurus hudsonicus gymnicus) . . 172 



Young Red Squirrel (Sciurus hudsonicus gymnicus) . 174 



Hoary Marmot (Arctomys Pruinosus) . . . . 174 



Pine Squirrel (Sciurus hudsonicus richardsoni) . . 176 



Flying Squirrel ( ' Sciuropterus volans) . . . . 178 



Common Mole (Scalops aquaticus) . . . . 188 



Star-nosed Mole (Condylura cristata) . . . . 188 



Marsh Shrew (Sorex palustris) 188 



Four Common Eastern Bats 198 



Sea-lion (Zalophus calif ornianus) 208 



Sea-lion (Zalophus calif ornianus), barking . . . 210 



Walrus Bulls and Cows (Odobenus rosmarus) . . . 212 



Fur Seals (Otoes alascanus) . . . . . . 216 



Harbor Seals (Phoca vitulina) 216 



Otter (Lutra canadensis) 222 



Skunk (Mephitis putida), crossing a stream . . . 226 



Mink (Putorius vison) 234 



Weasel (Putorius noveboracensis) ..... 234 



American Sable or Pine Marten (Mustela americana), . 244 



Wolverine or Carcajou (Gulo luscus) .... 246 



XI 



