MAMMALS. 



71 



fat for winter. Unlike most of our native mice tliey do not lay up 

 stores of food, but become excessively fat, and with the first cold 

 weather of autumn enter a long period of hibernation. Soft, warm 

 winter nests are constructed in little cavities well under ground, and 

 in these the mice curl up for their long winter sleep. Usually they 

 are not found abroad after the first killing frost in September and 

 are not again seen until the snow has disaiDpeared in April or May. 

 They are among the most harmless and attractive of the great variety 

 of little animals to which the odious name of mouse has been unjustly 

 given. They do not belong to the same family as any of the other 

 so-called mice or small rodents of the region, and in soRie respects 

 show a closer relationship to porcupines than to any other animal of 

 this country. 



Family GEOMYID^: Pocket Gophers. 



Saskatchewan Pocket Gopher: Thomomys taJpoides talpoides 

 (Richardson). — These plumbeous-gray pocket gophers belong to the 

 Plains country and may generally be distinguished from the rusty 

 brown form inhabiting the mountains by color, slightly larger size, 

 and in the females by the 



six pairs of mammae in- 

 stead of four. 



Specimens have been 

 taken in the Swiftcurrent 

 Valley between the Sher- 

 burne and McDermott 

 Lakes and on the Belly 

 Eiver at the ranger sta- 

 tion. In both these val- 

 lej's they are abundant in 

 the open prairie - grass 

 areas, but apparently they 

 do not go into the tim- 

 bered or mountainous part 

 of the park. Over the 

 plains to the eastward they have a wide range through western Mon- 

 tana and Saskatchewan and eastern Alberta. Among the prairie 

 grasses their little mounds of fresh black earth are conspicuous at 

 intervals along the lines of their underground tunnels, but the 

 animals are rarely if ever seen even by the inhabitants of the country. 

 Practically their whole lives are spent underground, except when for 

 a few minutes an opening is made to the surface, the loose earth 

 pushed out, and a few plants quickly cut and stuffed into the capa- 

 cious and fur-lined cheek pouches to be carried back into the burrows 



Photo, by N. H. Kent. m49S 



Fig. 12. — A pocket gopher of the genus Tlwmomys, 

 phoiogfaphed ffom a captive intlividual. 



