THE GROUND SQUIRRELS OF CALIFORNIA. 673 



bring the animals out into full activity. ' ' I caught sight of one standing 

 upright at the mouth of its burrow, squeaking, and of two others run- 

 ning over the sand beneath the trailing green mesquite branches. The 

 lines of footprints in the sand centering at the mouths of their burrows 

 are diagnostic. The animals are extremely shy, going below ground 

 at the slightest alarm. By standing ten minutes or so 'at attention' 

 about fifteen yards from the mouth of a burrow down which one van- 

 ished, I finally saw the top of its head reappear to the level of its eyes. 

 This position was maintained for many minutes, until the animal 

 suddenly raised its whole head and neck into view, when I shot it. 



''Later, while I was lying prone on the sand under a mesquite, one 

 came up to within eight feet of me and gave its shrill, wiry cry, or 

 squeak. A mere movement on my part, and it vanished, quick as 

 thought." It was found that a little "screeping" (lips to back of 

 hand) would often bring one of the squirrels stealthily investigating 

 through the brush, provided the observer kept perfectly motionless 

 himself and was possessed of patience. The squirrel would sometimes 

 squeak, apparently in answer, and thus be called into very close "aux" 

 range. The burrows were as a rule located in the periphery of a large 

 mesquite clump, where they were shaded by the radiating leafy branches 

 which trailed down the sandy slopes. Not more than three burrows 

 certainly of this rodent were to be found about any one clump. 



The mesquites during early April were just coming out into full new 

 foliage. The stomachs of the squirrels shot were distended with masses 

 of finely chewed mesquite leaves and nothing else. This, in fact, was 

 absolutely the only kind of vegetation anywhere in sight for hundreds 

 of yards. In one instance the total weight of the freshly killed animal 

 was found to be 154.5 grams; of the full stomach alone, 28.7 grams, or 

 19 per cent (near one-fifth) of the total weight. In other words, a 

 Death Valley Round-tailed Ground Squirrel may eat close to one-fourth 

 its own weight of green mesquite leaves. 



No young were seen by us up to the time of our departure, but they 

 are probably born about the first of May. Tavo old females captured 

 April 10 and 12 contained four and three embryos, respectively. 



PALM SPRINGS ROUND-TAILED GROUND SQUIRREL. 

 Citellus tereticaudus chlorus Elliot. 



Other names. — Pale Spermophile ; Citellus cMorus. 



Field characters. — Exactly as for the Yuma Round-tailed Ground Squirrel. 



Description. — As for the Yuma Round-tailed Ground Squirrel, but tone of colora- 

 tion more grayish, avellaneous rather than light pinkish cinnamon. This differencB 

 holds through all pelages and gives the impression of an olive-colored animal, when 

 close comparisons are made with series of the other related ground squirrels. 



Color variations. — Specimens showing the spring molt to be in process bear dates 

 from March 29 to as late as June 3. As with the other races of tereticaudus the 

 pelage on the tail is not replaced during the spring molt and it becomes greatly faded 

 and worn. In extreme cases the tail with its shortened, singed-lookiug hairs is a 

 dirty pale brown color throughout, and as slender as a wood-rat's tail. The summer 



. 6— 43C07 81 



