Page:Natural History of the Ground Squirrels of California.djvu/103

Rh we properly (from a scientific standpoint), consider any animal altogether apart from its normal surroundings.

In the Inyo Mountains this squirrel was found by H. S. Swarth (MS) to range from the level of the lowest piñons in Mazourka Canyon, about 7,500 feet altitude, to the highest summit visited by him, 10,500 feet. In the White Mountains, east of Laws, the senior author found it to range down Silver Canyon to as low as 7,000 feet altitude, and here this and the Antelope Ground Squirrel of the lower country overlapped in their ranges to a small degree. The "Callos," in such precipitous canyons as Silver Canyon, were essentially "rock" squirrels, in that they had their retreats in the slides of shale rock at the bases of the cliffs and even in the broken rock outcrops far up the canyon walls. Through and along these they clambered, a bit clumsily perhaps, but without loss of foothold so far as was seen.

Higher up, on the lofty rolling plateau forming the summit of this mountain range, the Golden-mantled Ground Squirrels were extremely abundant along the edges of the stunted forests of foxtail and lodgepole pines, and even far from timber out on the sagebrush flats, but in the latter locations there were always near at hand fractured granite outcrops which afforded safe retreats. Where there were grassy meadows the animals foraged all over them. It occurred to the observer that here in the White Mountains there was but this one species of ground squirrel and that it therefore had the run of the whole place, as it were, without meeting with any competitor, as is the case in the Sierras and elsewhere. This would account for the facts as observed, namely, that in the White Mountains the Copperheads were extraordinarily abundant and ranged widely into all sorts of associations.

Our lines of rat-traps baited with rolled oats brought in many "Callos," even youngsters but a third grown, and it was practically impossible to keep steel traps set during the day, as the bait, consisting of the bodies of the various birds and small mammals prepared for specimens, seemed to be especially attractive to the squirrels. Wherever the traps were set, they would be searched out and unwittingly sprung as the squirrels scrambled over them in quest of the bait. It seemed impossible that the "Callos" could have located some of the settings except through scent, and it is reasonable to suppose that the sense of smell is employed not only in seeking meat but when searching for the bulbs of certain plants.

Young were out in numbers the last week of July at the 10,000-foot level, being then one-third to one-half grown. Lower down, in Black Canyon at 8,000 feet altitude, half-grown young were seen on July 5 (1917); and at 10,500 feet altitude, on Cottonwood Creek, third-grown young were noted on August 8. This shows the usual variation of appearance of young with altitude, which of course has to do with advance of the season, and so with temperature.

In Mazourka Canyon, Inyo Mountains, two females, each containing six embryos, medium-sized and small, respectively, were taken May 19 and 22 (1912). We found no evidence of litters of a larger number than six; and there is certainly no more than one litter per year.