MAMMALS OF THE MEXICAN BOUNDARY. 31 7 



The form of the Eastern Desert Tract is extremely pale and doubt- 

 less separable as a g-eoj>-raphic race, but we got no specimens repre- 

 senting the extreme of this phase. During February and March none 

 appeared at El Paso, Texas. The tirst one was seen in the Carri- 

 zalillo Mountains, Chihuahua. It was wounded, but escaped among 

 the rocks in which it lived, and no specimen was obtained until we 

 reached the edge of the Elevated Central Tract, where the form begins 

 to lose its extreme pallor. 



Ilahlts and local distribution. — This large ground-squirrel of the 

 southern Rocky Mountain region is the only one of the Sciuridiv whose 

 distribution is general throughout the ti^rritory of Arizona. It is 

 alike at home in the low, desert regions and in the highest mountains. 

 I found it at the summit of the San Francisco Mountains, the highest 

 land in the territory, in June, 1887. It appeared to be the only 

 species of the family living above timber-line in those mountains, the 

 bighorn, or mountain sheep, being the only other mammal known 

 habitually to frequent the summit. 



This species, in Arizona designated as the "rock-squirrel" or 

 "canyon-squirrel," is both widely known and held in general disfavor, 

 from its abundance and its destructiveness to crops. In appetite it is 

 as omnivorous as the bear, feasting alike upon flesh, carrion, grain, 

 or almost any sort of fruit or green vegetation that chances to be in 

 season. 



Its flesh, though reputed to be very good, is seldom eaten, save by 

 Indians. Many persons referred to it with abhorrence, recalling the 

 current tales of its supposed interference with the graves of miners 

 buried in the mountains, which tales, doubtless, are not wholly without 

 foundation. 



At high altitudes, this rock-squirrel hibernates in winter. At Whip- 

 ple Barracks (altitude 5,318 feet). General Crook had dormant speci- 

 mens bi'ought to him in winter by Hualapai Indians. In the Verde 

 Valley (altitude 3,160 feet) it is much less active durinjr winter, but 

 was seen at all seasons, coming out oftenest when the s:n was shining, 

 and during the warmest part of the da}' in winter. 



Although manifesting a decided preference for rocky places, as 

 cliffs, canyons, and huge piles of rocks, which abound in many parts 

 of the Territory, this ground-squirrel is quite ubiquitous. In river 

 bottoms, and on the open plains, it excavates a burrow beneath a stone 

 or bush — preferably a mesquite — and readily adapts its habits to its 

 environment. Its appetite, likewise, seems to be governed by con- 

 venience rather than by any very decided preferences. In the vicinity 

 of cultivated lands maize, barley, and wheat are staple articles of its 

 diet, while in river flats the mes(juite and screw bean constitute the 

 largest elements of its food. The stomachs and cheek-pouches of the 

 specimens shot in the neighborhood of Fort Verde, in central Ari- 

 zona, contained a large variety of substances, varying according to 



