MOV N TAIN LIZARD 629 



The Mountain Lizard is common in and about the thickets of snowbush, 

 chinquapin, huckleberry oak, and other brush plants in the Canadian 

 Zone, hence, chiefly above the level of Yosemite Valley. It stays mostly 

 about and beneath the cover of this high mountain chaparral, though it 

 is sometimes to be seen on rocks and on logs. Its habitat is thus rather 

 different from that of the Tenaya Lizard ; the latter is more of a climber, 

 to be found on large granite boulders out in the open. 



Although we did not find them on the floor of Yosemite Valley, some 

 Mountain Lizards did come to our notice (June 8, 1915) on the uppermost 

 parts of the steep taluses on the north side of the Valley beneath Eagle 

 Peak. The altitude here is about 5000 feet, the lowermost station of 

 ascertained occurrence for the species anywhere in the whole region. In 

 our several trips up the Yosemite Falls Trail the first individuals were 

 met with at the 5750-foot contour. The highest station of occurrence in 

 the region was the summit of Ostrander Rocks, east of Glacier Point, at 

 8250 feet. 



These lizards, like all the other high mountain reptiles, must spend 

 fully half the year in dormancy, hidden away in crevices deep down among 

 rocks or in spaces among the stems of bushes or at the bases of stumps. 

 An early date, seasonally, for noting them is May 27 (1911), when several 

 were seen at noon and shortly after on the bare sunlit surfaces of the rocks 

 at the very summit of Eagle Peak (7700 feet) ; at that time there was deep 

 snow all about. Our earliest date, at a lower altitude, 6700 feet, near the 

 brink of Nevada Falls, is for May 18 (1919). Our latest record is for 

 October 11 (1914) near Yosemite Point. 



The Mountain Lizard is, when fully adult, only about 5 inches in 

 length. The head and body is about 21/2 inches long. It is decidedly 

 smaller than any of the other local species, though it might be confused 

 with young of the Fence Lizard. The body of the present species is cov- 

 ered, on the back and sides, with keeled or ridged scales which are of small 

 size. Between the last of the large plates of the head and a line drawn 

 across the back of the thighs there are usually 45 or more scales in a length- 

 wise row, whereas in the other 'swifts' (races of Sceloporus occidental is'^i 

 the scales usually number less than 45 (except in S. 0. taylori). (See 

 pi. 57a, h.) An additional character for distinguishing the two is found 

 in the condition of the scales on the back of the thigh ; in the present species 

 these are smooth, whereas in the other local Scelopori they are keeled. 



An individual of this swift comes to attention usually by reason of 

 the rustling noises it makes as it scurries about in the dry leafy debris 

 beneath the brush plants. Most of its time is spent within this type of 

 surroundings, and it is often difBcult to discover or to capture when it 

 takes to the shelter immediately afforded. The food of the species seems 



