628 ANIMAL LIFE IN THE TOSEMITE 



begin to venture forth from their winter retreats. At first they are abroad 

 only for a short time during the warmest of the mid-day hours, but by the 

 middle of summer in the foothill country they are active at, or shortly 

 after, sun-up and thenceforth throughout the day, even until well after 

 sundown. In Yosemite Valley in 1916 several were abroad at the end 

 of April, and at El Portal they were out in numbers on May 2 the same 

 year. The latest seasonal record is of several abroad at Sweetwater Creek 

 on October 28 (1915). 



With the Tenaya Blue-bellied Lizard in the higher altitudes the season 

 is shorter. Our earliest record for the species is May 16 (1919), when 

 one was seen at Sierra Point. On May 18 that year numbers of males 

 were in evidence in Little Yosemite Valley. A note made on August 28, 

 1915, near Washburn Lake states that these lizards had not become active 

 until about 9 o'clock in the morning. The last appearance of the species 

 seasonally, in 1915, was on October 1, when one was obtained at 7300 feet 

 in the Tuolumne Canon below Glen Aulin. 



The male Blue-bellied Lizard has a curious habit of alternately raising 

 and lowering the forepart of the body by straightening and then flexing 

 the fore legs. When the body is lifted up in this manner the coloring on 

 the under surface may be glimpsed. Once, in Little Yosemite Valley 

 (May 18, 1919) several males (of subspecies tayJori) were seen going 

 through an even more elaborate performance than that just described. 

 These particular lizards had puffed out their bodies and throats to about 

 twice their natural size. Then they worked up and down several times 

 on all four legs. Thereafter they deflated somewhat and continued the 

 exercise, on the front legs alone. Although this movement is common, 

 its purpose is as yet without a satisfactory explanation. From the momen- 

 tary display of the bright color on the under surface of the body one might 

 infer it to be a courting antic, comparable to the spreading of wings and 

 tail, with consequent exhibition of bright markings, which is to be seen 

 in many species of birds in the mating season. 



Mountain Lizard. Sceloporus graciosus graciosus Baird and Girard 



Field characters. — Size small, total length 5 inches or less; scales everywhere very 

 small, less than 146 i^^ch across; those of back, sides and tail ridged or 'keeled'; 42 

 or more scales in lengthwise row between back of head and line across back of thighs. 

 (See pi. 57«.) General coloration of body above greenish or brownish gray, with 6 

 lengthwise rows of irregular dark blotches along back and sides; middle of under surface 

 of body and whole under side of tail pale yellow; chin region and sides of belly deep 

 blue in males, light bluish in females, but never with two separate blue patches on throat. 



Occurrence. — Common resident in Canadian Zone on west side of Sierra Nevada. 

 Eecorded from Pilot Peak ridge and from Chinquapin eastward to Porcupine Flat and 

 to Merced Lake. Also present east of mountains in Canadian and Transition from 

 Walker Lake to Mono Craters. Lives chiefly on ground beneath brush plants, but to 

 some extent around logs and rocks. Active in the warmer parts of summer days. 



