WHIP-TAILED LIZABB 633 



ticularly those of the hind feet. When frightened, one of these animals 

 appears to get over the ground, for a short distance at least, faster than 

 a man can run. Its usual procedure is to start up suddenly, make a rapid 

 dash of 50 to 100 feet or so, then stop abruptly, often dodging around 

 behind a bush at the instant of stopping. The long tail serves as a counter- 

 poise and perhaps also as a rudder, in movement. The sudden start, 

 extremely swift run and quick stop are, to the human eye, confusing, and 

 may have the same effect on any animal, such as the Road-ninner, which 

 might attempt to prey on the lizards. When undisturbed the Whip-tail 

 forages about with jerky movements of the body. The tail is then usually 

 dragged on the ground and leaves a characteristic trail between the marks 

 of the feet. When pursued, one of these lizards will often take shelter 

 in some hole in the ground, usually at the base of a bush. One was seen 

 to enter a ground squirrel burrow. In places where there are no open 

 rodent burrows, and where the soil is sufficiently loose. Whip-tails dig their 

 own burrows. 



At Smith Creek a small whip-tailed lizard was seen in a pool of water, 

 where it had evidently jumped when frightened by the approach of the 

 observer. The animal was obviously unadapted to this element, for after 

 a few strokes it sank to the bottom and was drowned. 



The Whip-tail subsists upon insects. Some of these, such as grass- 

 hoppers, are obtained by stalking, just as a carnivorous mammal such as 

 a coyote stalks a ground squirrel. Other prey, such as cutworms (moth 

 larvae) and beetle larvae, are picked up by the Whip-tail from the surface 

 of the ground about the bases of plants. This lizard does not climb at all, 

 even over rocks. 



Western Skink. Plestiodon skiltonianus Baird and Girard 



Field characters. — Scales flat, thin, and not ridged or beaded, overlapping (shingled) 

 and forming a very smooth body covering; body and tail evenly tapered to slender tip 

 of tail; both pairs of legs short, scarcely longer than diameter of body (pi. 58a). 

 Adults: Head coppery red; body olive brown above, bluish green on sides, pale beneath; 

 tail pinkish red (pi. 12c). Young: Head and body dark brown, with two sharply 

 defined yellowish stripes along back; under surface pale blue; tail brilliant blue (pi. 

 12b). Total length of adults: Head and body up to 4% inches, tail to 6% inches. 



Occurrence. — Common resident throughout western part of Yosemite section, from 

 Lagrange and Pleasant Valley eastward to Yosemite Valley. Forages in shaded places, 

 in leafy debris in thickets and under trees; has retreats under stones, logs, boards, etc., 

 and down rodent burrows. 



Most interesting among the several species of lizards in the Yosemite 

 region is the Western Skink, a peculiarly smooth-bodied reptile, notable 

 for its brilliant coloration and for the great difference in color pattern 

 between young and old individuals. (See pi. 12&, c.) 



