146 ANIMAL LIFE IN THE YOSEMITE 



Scanty data were obtained relative to the breeding of the local pocket 

 mice. At Snelling on May 26, 1915, two female San Joaquin Pocket Mice 

 were captured which contained 2 and 6 embryos respectively. A nearly 

 full grown young-of-the-year in the bluish-tinged soft pelage of immaturity 

 was taken at the same station three days later. On the California Pocket 

 Mouse we have only three notes : Two females with mammae conspicuous 

 were taken on May 21 and 27, 1915, at Pleasant Valley, and a nearly grown 

 juvenile was collected at Smith Creek (6 miles east of Coulterville ) on 

 July 28, 1920. For the Great Basin Pocket Mouse, although numerous 

 specimens were obtained, the data are likewise scanty. A female containing 

 3 embryos was captured at Mono Lake Post Office on July 1, 1916, and an 

 immature animal was trapped on Dry Creek, June 12, 1916. At Walker 

 Lake, September 9 to 13, 1915, and near Williams Butte, September 17 

 to 22, 1915, numerous smooth-pelaged gray-tinged but nearly or quite full- 

 sized young-of-the-year were procured. 



Kangaroo Rats. Genus Dipodomys'^ 



Field characters. — Body size between that of House Mouse and House Eat, nearer 

 the latter (see footnote 13 for detailed measurements) ; tail exceeding head and body 

 in length, well haired, and with a conspicuous tuft at end (pi. 26e) ; front feet very 

 small, hind feet and legs disproportionately long and large; ear rounded, held close to 

 side of head; a large fur-lined cheek pouch on each side of face opening outside of 

 mouth; eyes large; pelage silky. Coloration above plain sandy brown (varying in tone 

 according to subspecies) ; a white stripe across each thigh ; whole under surface of body 

 pure white; end of nose white with a blackish crescent on each side; tail four -striped — 

 dark stripe above and below, with an intervening white stripe on each side. Workings: 



13 Three races of Kangaroo Rats are found in the Yosemite region. They are distinct 

 from one another structurally and occupy separate geographic areas, yet their habits and 

 general appearance are much alike. 



Heermann Kangaroo Eat, Diimdomys heermanni heermanni (Le Conte). Found 

 along the west base of the central Sierra Nevada. It was recorded from 1 mile west 

 of Coulterville to 6 miles east of that place, and probably occupies a much lender range 

 than this indicates. It inhabits the Upper Sonoran Zone, ranging locally into the lower 

 margin of Transition, and lives chiefly amid chaparral. Head and body 4i/4 to 4% inches 

 (108-123 mm.), tail Gi/o to 7% inches (165-187 mm.), hind foot about 1% inches 

 (43-44 mm.), ear from crown about % inch (12-16 mm.), weight about 2i/4 ounces 

 (68.6-72.8 grams). 



Merced Kangaroo Eat, Dipodomys heermanni dixoni (Grinnell). A subspecies 

 inhabiting the east side of the San Joaquin Valley (Lower Sonoran Zone). It was 

 recorded at Snelling, near Merced Falls, and below Lagrange. It inhabits open sandy or 

 dusty places. From heermanni it is distinguished by smaller size and average lighter 

 color. (See pi. 26e.) Head and body 3% to 4% inches (98-119 mm.), tail 6 to 6% 

 inches (155-174 mm.), hind foot about 1% inches (39-42 mm.), ear from crown about 

 % inch (12.5-14 mm.), weight ly^. to 2% ounces (43.4-68.4 grams). 



Pale-faced Kangaroo Eat, Dipodomys leucogenys (Grinnell). A species distinct 

 from the two preceding in several particulars, and readily separated from them by 

 larger size and paler coloration. It is rather common at Mono Mills, on the slopes of 

 Mono Craters and along Dry Creek; all these localities are near Mono Lake east of the 

 Sierra Nevada. It inhabits sandy places among the sagebrush. Head and body 4% 

 to 51/2 inches (117-140 mm.), tail 61/3 to 7% inches (160-185 mm.), hind foot about 

 1% inches (44-47 mm.), ear from crown at)Out ^2 inch (12-13 mm.), weight 2% to 

 314 ounces (78.2-88.5 grams). 



