r 



In build llicy arc specially adapted lo this uii(l(ir<^rouiid life, 

 liaviii<;- short, thick bodies and powerful foreleg-s armed with long 

 claws adapted for digging. Thci eyes and ears are small ; the in- 

 cisors or front teeth are long and sharp, and used on a pick to loosen 

 the dirt. The external cheek pouches are used oidy to carry food. 



Genus Thonwniys 



Pcv'ket-gophers of this genus are distinguished by their small 

 size, upper incisor teeth without the median line as in Geoniys, 

 and the inner edge with a slight groove. The legs and fore feet 

 are built for digging, but do not have the powerful build as in 

 Gecmijs or Cratogomys. Total length from about I'-Yi inches to 9\(> 

 inches. In color they range from dark brown to buffy gray ; eyes 

 small and shot-like ; neck not noticeable. 



C olora do Hp ecies. 



Yellow Pocket-Gopher, Thcmom^is po paUidns aureus. 



Jicarilla Pocket-Gopher, Thomomys perpallidus apache. 



Fulvous Pocket-Gopher, Thomomys fulvus fulvus. 



Espanola Pocket-Gopher, Thomomys fuI/Dus pervagus. 



Coues' Pocket-Gopher, Thomomys talpoides clusius. 



San Luis Pocket-Gopher, Thomomys talpoides agresiis. 



Green River Pocket-Gopher, Thomomys ocius. 



Colorado Pocket-Gopher, Thomomys fossor. 



The distribution of the genus Thomomys in Colorado is, 

 roughly speaking, from longitude 105° westward to the Colorado- 

 Utah line. They range at a high altitude. I saAv gopher workings 

 at Corona, Boulder County, altitude 11,660 feet. 



The food of pocket gophers consists of alfalfa roots and other 

 forage crops, parsnips, carrots, beets, potatoes, melons, bulbs of 

 lowering plants, etc. They also damage small trees by cutting 

 the roots just below the surface of the ground. Their runways 

 often cause ground on side hills to wash, either with rain or irri- 

 gating water, and ditch banks to break, and their mounds thrown 

 up in meadows and alfalfa fields cause breakage of sickle bars 

 when mowing. 



Pocket-gophers practically round out their life cycle in their 

 underground burrows, seldom coming to the surface, and then only 

 at night. It has been the common belief among naturalists that 

 this: only occurs during the rutting season, when they are seeking 

 mates. Recently Mr. Harold C. Bryant (University of California 

 Publications in Zoology, Vol. 12, No. 2, pp. 25-29, 1913) has, in a 

 way, disapproved this theory. I quote from his article, page 22: 



15 



