THE GROUND SQUIRRELS OP CALIFORNIA. 



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MOHAVE GROUND SQUIRREL. 

 Citellus mohavensis (Merriam). 



PLATE IV. 



Other names. — Mohave Desert Spermophile; Mohave Desert Ground Squirrel, part; 

 Spermophikis mohavensis; Citellus tereticaudus mohavensis, part. 



Field characters. — A small-sized, brown-colored ground squirrel, without stripes 

 or special markings whatsoever on the body, but with short broadly haired tail, 

 white underneath ; ear a mere rim ; length of body alone, about inches, with tail 

 about 2i inches more. 



Description. — Adult in full winter pelage: General tone of whole upper surface 

 from nose to base of tail cinnamon drab ; hairs on back when examined closely are 

 seen to be lead-color at base, then ashy white, then army brown, and tipped with 

 white ; mixed with these hairs are a few of solid black color, and on the rump some 

 which are black with a white interval near end. Eyelids white, but cheeks like 

 back ; rim of ear and upper sides of feet tinged with light pinkish cinnamon ; palms 

 of fore feet naked ; soles of hind feet clothed with long buffy hairs ; claws black with 

 horn-colored tips. Under surface of body silvery white, but slaty bases of hairs show 

 through making the general effect light gray. Under surface of the flattish stubby 

 tail pure white ; upper side like back at base, becoming mixed black and white toward 

 end ; extreme end with white fringe. Adult in summer pelage : Coat very much 

 coarser and shorter than in winter ; general color tone browner, close to cinnamon, 

 but a grizzling effect is produced by white hair-tippings everywhere on upper surface. 

 Sides of face paler than in winter, and lower surface of body pure white, owing to 

 lack of lead-color at bases of individual hairs. 



Color variations. — Specimens of dates May 3 and 12 are in process of molt from 

 winter to summer pelage. Patches of worn and yellowed winter hairs remain on the 

 fore back and rump. The tail is seemingly not included in the spring molt, and the 

 old tail hairs become crinkled and broken at the ends ; the white of the under side 

 is dingy, and a dark subterminal band around the end of the tail shows through. 



Measurements. — Average and extreme measurements, in millimeters, of seven adult 

 specimens (5 males, 2 females), from the northern part of the Mohave Desert are 

 as follows: Total length, 224 (212-230) ; tail vertebrae, 62 (42-72) ; hind foot, 36 

 (34-37) ; greatest length of skull, 38.6 (38.1-39.0) ; zygomatic breadth, 24.3 

 (23.6-25.3) ; interorbital width, 8.7 (8.2-9.2). 



The two sexes appear to be alike in measurements as well as in coloration. 



Weights. — An adult male, not particularly fat, was found to weigh 104 grams 

 (about 3f ounces). 



Type locality. — Mohave River, California (Merriam, 1889, p. 15). More exactly, 

 near Rabbit Springs, about 15 miles east of Mohave River at Hesperia, in San 

 Bernardino County (Stephens, in conversation, January 1, 1916). 



Distribution area. — Not continuous; western parts of the Mohave Desert, from 

 Haiwee, Inyo County, south to Rabbit Springs, San Bernardino County (see 

 fig. 18). Life-zone, Lower Sonoran, though only in its upper portion apparently. 

 Altitudinal range, 2,500 to nearly 4,000 feet. 



Specimens examined. — A total of 8, from the following localities in California: 

 Inyo County : Haiwee Meadows, 3,750 feet alt, about ten miles south of Owens Lake, 

 2 (in coll. U. S. Biol. Surv.) ; Little Lake, 3,100 feet, 2 (Mus. Vert. Zool.). San 

 Bernardino County: Salt Wells Valley (eastern edge near Inyo County line), 2,500 

 feet, 3 (U. S. Biol. Surv.) ; Rabbit Springs, 2,900 feet, east of Mohave River, 1 (in 

 coll. F. Stephens). 



The Mohave Ground Squirrel, although first discovered in 1886 by 

 Mr. Frank Stephens of San Diego, has remained about the least known 

 of all our rodents. Only four rather scattered localities of occurrence 

 are definitely known, as listed above under ' ' Specimens examined. ' ' 

 The dates represented are March 22 and 24, May 3 and 12 and June 5. 



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