EANGABOO SATS 147 



Burrows about 2 inches in diameter, in loose soil, usually about bases of bushes ; entrance 

 hole usually filled with earth during the daytime. Tracks: Paired impressions of hind 

 feet (3 or 4 toes showing forward, connected with a long heel print) in lengthwise series 

 at intervals of 7 to 36 inches, the tail track as an interrupted line midway between the 

 footprints (pi. 40c). 



Occurrence. — Resident along east side of San Joaquin Valley, at Snelling, near 

 Merced Falls, and below Lagrange (dixoni), in western foothills about Coulterville 

 (heermanni) , and again east of the Sierra Nevada around Mono Lake (leiicogenys).^^ 

 Nocturnal. 



The Kangaroo Rat is a type of mammal which has developed in response 

 to the sandy desert conditions obtaining in the southwestern part of North 

 America. The territory at either end of the Yosemite cross-section, being 

 rather arid in character and otherwise suitable, is occupied by a moderate 

 population of this rodent. The name kangaroo rat refers to the mode of 

 progression which, like that of the Australian kangaroo, is accomplished 

 by catapultic leaps with the long hind legs and feet, in which operation the 

 greatly lengthened tail acts as a stabilizer and support. Another special 

 feature, the external fur-lined cheek pouch on each side of the face, used, 

 as with the pocket gopher, for the storage of clean food materials, has led 

 to the name pocket rat for this rodent. 



Further description of the kangaroo rat may be of interest, particularly 

 as the animal itself is rarely seen in the wild alive though it has been found 

 to submit readily to captivity. The form is somewhat tapered, the nose 

 being pointed and leading back to a rather flattish head. The forelegs and 

 feet are small, but the hind legs and feet, the leaping apparatus, comprise 

 quite the largest part of the animal (pi. 266). The tail is long, well exceed- 

 ing the head and body in length, and is covered with hair which, toward 

 the tip, becomes long and forms a tuft, or better, a 'brush.' The nose is 

 provided with an elaborate set of vibrissae or 'whiskers,' the longest of 

 which reach out far beyond the side of the body. The ears are rather small 

 though the hearing ability of these animals is probably acute to judge from 

 the enlargement of the back portions of the skull which house the internal 

 ear structures. The whole pelage of the animal is soft, even silky in texture. 

 The kangaroo rat habitually travels and rests on its hind feet, the fore ones 

 being devoted to .the handling of food materials and to cleaning the fur. 



Most species of kangaroo rats inhabit sandy situations, so that, as a rule, 

 naturalists have come regularly to look for the animals in such places. 

 The Merced and Pale-faced kangaroo rats of the Yosemite region frequent 

 sandy ground. But the Heermanu Kangaroo Rat which lives in the western 

 foothill country dwells in the chaparral where there is seldom any sand 

 and where usually the ground is gravelly or even rocky in nature. Its 

 niche is evidently much like that of the California Pocket Mouse. The 

 special requirement of the kangaroo rat is a location in which it can place 



