136 ANIMAL LIFE IN THE YOSEMITE 



The Pocket Gopher is a modest, retiring animal of subterranean habits, 

 known chiefly by his works. Indeed so rarely is one of the animals seen 

 alive by the casual observer that the evidences of its presence are often 

 ascribed to that totally unrelated but more widely known animal, the mole. 

 There is close similarity in general appearance and habits between the 

 several species of pocket gophers inhabiting the Yosemite region, and for 

 this reason it has seemed better to combine in one account what we have 

 learned about all of them. Brief descriptions of the five species and state- 

 ments of their respective ranges are given in footnote 11. 







Fig. 22. Illustrates method used by Mole in putting earth up from below-ground. 

 Successive loads of earth are forced up one after another and topple out on the surface 

 of the ground, volcano-like, without ever leaving the mouth of the tunnel exposed or 

 open. Compare with figure 23 illustrating work of Pocket Gopher. 



Gophers live in tunnel systems which they themselves excavate at a 

 relatively uniform depth five inches or so below the surface of the ground. 

 They appear on the surface from time to time only when necessary to push 

 out earth loosened in extending their tunnels or to forage in the close 

 vicinity of the open burrow. They seem to be most active about sundown 

 and during the early hours of the morning ; for it is then that the majority 

 of new surface mounds appear, and that the animals themselves are most 

 often seen at the mouths of open burrows. 



The presence of gophers is indicated by small mounds of loose earth 

 which the animals push out here and there on the surface of the ground. 

 The typical mound is of a fan shape, the opening of the burrow from which 

 the earth was pushed, although closed, being clearly indicated at the base 

 of the fan. (See pi. 28&.) The upraised surface of the fan is marked with 

 more or less sharply indicated concentric 'moraines,' each registering the 

 terminus of an operation from the mouth of the burrow. The rim of the 

 mound is often irregular, the earth having been pushed farther out at some 

 points on the periphery than at others. The mouth of the burrow is plainly 

 outlined in a perfect circle of raised earth two or three inches in diameter, 

 but this small circle is lower than the preponderance of the heap. 



