148 ANIMAL LIFE IN THE YOSEMITE 



its burrow; the animal does all its foraging out on the surface of the 

 ground. No burrows were opened up by us in the Yosemite region, but 

 in other places the underground retreats have been found to be of relatively 

 simple nature, used as shelters during the daytime and in cold or rainy 

 weather, and as storehouses for food to be eaten when the animals cannot 

 well venture out. 



The distance which a kangaroo rat can cover in one leap is apt to be 

 over-estimated. On any of the relatively few occasions when we have seen 

 one of these animals abroad during the daytime, it has made off so suddenly 

 that we were practically at a loss to describe what transpired during the 

 few seconds that the animal continued in sight. In cases where the actions 

 of an animal have been observed successfully the extent of a single leap has 

 been found to be moderate ; one jump followed another so rapidly, however, 

 that the rat's progress was amazingly swift. Speedy escape is likely to 

 be interpreted as due to the animal's ability to jump prodigious distances, 

 whereas the real basis is rapidity of action. Animals frightened or turned 

 out of their burrows when ground was being plowed have been seen to 

 cover 3 to 4 feet at a leap. Under extremely favorable circumstances 

 this might be slightly exceeded. The tracks of an undisturbed Heermann 

 Kangaroo Rat seen in a dusty road near Coulterville were (heel to heel) 

 from 7y2 to 9 inches (190-230 mm.) apart. Where something in the road 

 had claimed its attention and the animal had loitered the tracks were even 

 closer. (See pi. 40c.) 



The normal activity of the kangaroo rat is confined to the hours of 

 darkness. Unless disturbed by man or some native enemy, it rarely or 

 never ventures out in the daytime. But as soon as dusk has fallen it leaves 

 its burrow and goes hunting for food. The animal subsists almost entirely 

 upon small seeds of particularly sought kinds. Material is gathered and 

 stuffed into the cheek pouches, then the rat retires to its burrow where 

 the food materials are deposited in a special chamber, to be shucked out 

 and consumed at leisure. Examination of the cheek pouch contents of 

 captured animals indicates that a variety of wild seeds are used as food; 

 but when cultivated grains are available the animals turn to these, especially 

 where the fields adjoin wild land. Kangaroo rats readily take the poisoned 

 grain put out for ground squirrels and many meet death from this cause. 

 Ploughing of new land destroys their burrows and quickly drives them out, 

 so that this rodent rarely becomes an important enemy of man. 



Our specimens of the Heermann Kangaroo Rat were all taken in the 

 neighborhood of Coulterville, from Blacks Creek on the west to Smith 

 Creek, 6 miles east of the town. But the species enjoys a much wider local 

 range, for we found tracks in the dust of roads at Pleasant Valley, closed 

 burrows on the greasewood slopes about El Portal in December (when the 



