THE POCKET GOPHER 



109 



Measurements. — Total length, 11.00 inches; tail vertebrge, 3.25 

 inches; hind foot, 1.50 inches. 



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FIG. 28. — Faces of Pocket Gopliers, showing pouches and incisors. (From U. S. 

 Department of Agriculture.) ' ' '"' j 



The pocket gopher shows but little tendency to variation in color 

 according- to season, but the variation in size, due principally to 

 difference in sex, is quite pronounced. The females are always 

 smaller than the males, the discrepancy in this species being as 

 much as an inch in total length, a half inch in length of tail and 

 from three to five millimeters in length of hind foot. In addition, 

 differences in cranial .characters, aside from the matter of size, 

 are apparent in the two sexes; the female usually has a broader 

 and flatter brain case, the zygomatic arches are narrower, the 

 rostrum and nasals shorter, and the entire skull smoother than is 

 characteristic of the male. 



Habits, Distribution, Etc. — The pocket gopher is of more eco- 

 nomic importance than all of the other species of the family together 

 and in Iowa at least is of greater consequence economically than 

 all our' other species of rodents combined. Iowa is fortunate in 

 that she is furnished with a great deal of exceedingly fertile land, 

 but unfortunate in that this rodent pest is apparently most at 

 home in just such rich and densely populated cultivated territory. 

 A very conservative estimate indicates that the annual loss to agri- 

 cultural interests in the state of Iowa due to depredation by the 

 pocket gopher amounts to a half million dollars This is a sum 

 which is worthy of consideration and which could be materially 

 reduced by proper and uniform control measures, which will be 

 discussed below. 



The pocket gopher lives almost entirely in underground tunnels 

 which it excavates in loose alluvial soils rather than in those wdiich 

 are hard or clayey. Sandy soils are seldom Avorked, since burrows 

 can not be successfully constructed in such loose material ; as a 



