144 NORTH AMERICAN FAUNA [No. 55 



sometimes among the rocks. In a barren country where wide forag- 

 ing is necessary the speed and alertness of these little sand squirrels 

 is of vital importance. 



Their voice, a shrill, prolonged chipper or bubbling whistle, is 

 often heard during the summer when the young are out and the old 

 females are watching for danger, or the young call back and forth, 

 but at other times they are rarely heard. 



In winter they become very fat but apparently do not regularly 

 hibernate, as specimens are taken throughout the year. In very 

 cold weather or deep snow, they may hibernate for a time, but their 

 tracks are sometimes seen on the snow, and they are often found 

 active in freezing weather in midwinter. 



They are sturdy, vigorous, energetic little animals, quick to run 

 but fierce fighters when cornered, with none of the gentle, quiet ways 

 of some of the little ground squirrels. One kept in captivity for 

 more than a year never became tame, nor would allow handling. 

 When disturbed, it would rush to the vertical wheel and spin it with 

 intense energy. It would even run the wheel at night if alarmed, 

 although in the wild the species is wholly diurnal. 



Breeding habits. The young are usually 6 or 8 in number, but 

 there is one record of 12 large embryos in a female collected April 1. 

 This is evidently an abnormal number as the mammae of the females 

 are in 5 pairs 1 inguinal, 2 abdominal, and 2 pectoral. Farther south 

 the young are born in early April and are out of the burrows by 

 the middle of May, but in Oregon the dates may be a little later. 

 The young are about a quarter grown when they first come out of 

 the burrows and remain for some time under the care and protection 

 of the mother. When nearly full grown in the late summer they 

 scatter out and live independent though not unsociable lives. 



Food habits. In summer these squirrels eat a great deal of green 

 vegetation, cactus fruit, and berries and green seeds, but in autumn 

 and winter they live largely on seeds and grain. One collected in 

 Warner Valley by Jewett on September 26, 1915, had its cheek 

 pouches filled with several hundred seeds of Russian-thistle, and 

 nothing else. They are fond of all kinds of grain, also, and will 

 gather about stacks, barns, or corrals for scattered grains. 



Economic status. In the Oregon part of their range these little 

 squirrels are so scarce as to do no harm and are important only 

 as objects of interest. In fact, throughout most of their wide desert 

 range they have very little economic significance, but are always an 

 attractive form of desert life. 



CITELLUS DOUGLASII (RICHAUDSON) 



DOUGLAS'S GROUND SQUIRREL; DIGGER SQUIRREL; GRAY DIGGER; CHO-CHUCK 

 the Klamath (C. H. M.) ; WASCHOI of the Wasco 



Arctomys (Sperm-ophilus) douylasii Richardson, Fauna Boreali-Amer., v. 

 p. 172, 1829. 



Type. Collected along banks of Columbia River, Oreg., by David Dougl 

 in 1825. 



General characters. As large or larger (pi. 29, A) than the eastern gr* 

 squirrel; ears about as long; tail long and bushy but less full and spreadii 

 than in the tree squirrels; claws fossorial; palms naked; soles hairy back < 

 tubercles; cheek pouches ample. Pelage coarse and harsh; in summer, upper 

 parts dark brownish gray, mottled and scalloped with white specks and wavy 



