44 ANIMAL LIFE IN THE YOSEMITE 



of Yosemite Valley there is an unusually large mole population, and, as 

 gophers are present also in considerable numbers, the habits of the two 

 may there be studied and compared to good advantage. 



The mole is rather more strictly subterranean than the gopher. The 

 latter animal is not infrequently seen at the mouth of its burrow, and 

 occasionally it comes clear out on the top of the ground. The mole, how- 

 ever, habitually stays below the surface. All of its foraging is done in the 

 ground; even when excavating a burrow, the animal itself is not exposed 

 to view from above. Moles are said to run about on the surface of the 

 ground at mating time, but of this we have no direct knowledge. 



Fig. 5. Forefoot of (a) Yosemite Mole and of (&) Sierra Nevada Pocket Gopher. 

 The Mole's palm is greatly expanded and the claws are relatively huge, which features 

 too'ether with powerful arm and shoalder muscles make it possible for the animal almost 

 literally to swim through the earth ; the Gopher 's foot is less extreme, yet with elongated 

 claws for special service in digging and with hairs between the toes which serve to 

 increase the area of the foot when loose earth is being pushed out of or along the 

 burrow. Natural size. 



In physical configuration the mole is admirably suited for life under- 

 ground (pi. 27c). Its nose is long and pointed and equipped with 

 numerous fine sensory bristles. The mouth opens on the under side of 

 the head where dirt is less likely to enter when the animal is burrowing. 

 The head joins directly onto the firm stout cylindrical body without any 

 constriction at the neck region. The body as a whole is an 'entering 

 wedge.' The forelegs are extremely short so that the feet lie close along- 

 side the head. The front feet are highly modified to form 'spades,' the 

 palms being enlarged into thickened discs and turned outward, and the 

 nails or claws being elongated and very stout. By means of these broad 

 strong members the mole literally swims through the loose surface soil. 

 The hind feet are much smaller and quite normal in shape and function. 

 The body ends behind abruptly, and there is a short tail but scantily haired. 

 The whole body of the mole is densely covered with short hairs of remark- 

 ably uniform length and texture which give a silky plush-like effect to the 

 pelage. This sort of coat enables the animal to pass through the ground 

 with a minimum of resistance ; in other words, it acts as a lubricant. 



The mole makes and uses two distinct sorts of underground passage- 

 ways. One of these is the 'surface' runway, actually a subsurface run 

 or subway, an inch or less below the top of the ground. The mole ' swims ' 

 along by strokes of the forefeet ; its feet and body push the soil up in a low 



