1936] MAMMALS OF OREGON 251 



farmer and orchardist, however, have a more serious grievance, for 

 the gophers regularly reduce their incomes unless persistently de- 

 stroyed by every possible means. 



Ordinary-sized pocket-gopher traps are not large enough to hold 

 this species, and special large-size traps have to be made for them. 

 These rodents are easily poisoned, however, by dropping pieces of 

 sweetpotato or carrots containing strychnine into their burrows. 

 Green leaves of clover or alfalfa moistened and dusted over with 

 strychnine and pushed well down into the burrow would probably 

 kill these as well as it does other pocket gophers. 



THOMOMYS TOWNSENDII TOWNSENDII (BACHMAN) 

 TOWNSEND'S POCKET GOPHER 



Geomys toivnsendii Bachman (from Richardson's Manuscript), Acad. Nat. 



Sci. Phila. Jour. 8: 105, 1839. 

 Tfiomomys nevadensis atrogriseus Bailey, Biol. Soc. Wash. Proc. 27: 118, 



1914. Type from Nampa, Idaho. 



Type. Erroneously labeled "Columbia River" but evidently from southern 

 Idaho and probably from near Nampa where Townsend, who collected it, 

 camped to trade with the Indians on August 22, 1834. 



General characters. Large, next to bulbivarus ; ears small but pointed ; mam- 

 mae in four pairs ; skull wide and angular, with slightly protruding incisors ; 

 dichromatic, a dark gray and a black phase; in the gray phase upper parts 

 dark buffy gray or sooty gray ; nose and face blackish ; ear patches black ; feet 

 and tail gray; lower parts washed with rich buff. In the black phase dull 

 slaty black all over except white patches on chin and toes and usually on lower 

 part of feet. 



Measurements. Adult male: Total length, 305 mm; tail, 100; foot, 38; ear 

 (dry), 7. Female: 276; 75; 35. 



Distribution and habitat. These very large and dark-gray or 

 black pocket gophers occupy the fertile valley bottoms of the Snake 

 River in Idaho and the Malheur, and Owyhee Valleys in Oregon, 

 a rather restricted range in Upper Sonoran Zone (fig. 56). They 

 do not extend into the dry sagebrush country beyond the moist and 

 fertile bottom lands and usually do not overlap the range of the 

 smaller forms of the surrounding country. In favorable locations 

 they are abundant, and their large hills of mellow sand sometimes 

 cover nearly half the surface of the ground. 



General habits. Like all pocket gophers these animals live mainly 

 underground in endless tunnels, throw up numerous earth mounds, 

 or " gopher hills ", and travel only as fast and as far as their burrows 

 carry them. This is sufficient, however, to bring them into choice 

 fields of alfalfa or other crops affording favorite food, and new 

 fields in the irrigated valleys often suffer severely until the gophers 

 are caught, poisoned, or driven out. On well-irrigated lands the 

 water fills their burrows and soon drives them out but only to the 

 edges of the fields where they soon work back if not destroyed, or 

 into other fields where the water has not flooded the ground. 



Breeding habits. These pocket gophers breed early in the spring 

 as shown by Everett E. Horn in experiments near Vale, Oreg., in 

 1921. On March 27, a female and 5 young not yet weaned were 

 taken from one burrow, and the old female was found to contain 

 6 well-developed foetuses. Nine other females taken in the few 

 days following were suckling young, and 4 of these also contained 



