20 University of Michigan 



This lizard is the characteristic reptile of the mountains, and 

 was found elsewhere only on the group of low hills between 

 the Susan and Maggie Creeks and in the lower part of James 

 Canyon. It was not, however, of general distribution in the 

 mountains nor confined to particular elevations, but was very 

 closely restricted to rocky places such as cliffs, outcrops, talus 

 slopes, stream beds and similar places. Wherever such condi- 

 tions were encountered, from the basin of the Humboldt to 

 the top of the Carlin Peaks (7,754 feet), the species was found 

 in numbers. Occasional individuals both in the mountains and 

 on the plain were observed at a little distance from rocks but 

 these were only rare stragglers. The importance of rocks in 

 the habitat was also shown by the presence of a considerable 

 colony on the group of low rocky hills in the valley of Maggie 

 Creek and several miles from other outcrops. It is of interest 

 that the species was also present in some numbers on large 

 blocks of earth at the foot of a steep bank in the lower part of 

 James Canyon. In this place the earth was very hard and the 

 blocks were quite like rocks in form. That it was not found in 

 the Pinyon Range is with little doubt to be attributed to the 

 fact that the outcrops in the area studied were very small. 



As has often been noted, this Sccloporus is an excellent 

 climber. It clings with ease to a vertical or even overhanging 

 rock face and when alarmed rushes away with surprising 

 swiftness. In this habitat it is quite inconspicuous, the pattern 

 of light-colored individuals resembling the color of the rock, 

 and the dark individuals appearing very like a crevice or angle 

 in the rock face. When on the rocks, many of the old individuals 

 are entirely black above to the obliteration of the pattern, but 

 this color rapidly changes when they are removed. This black 

 color is not only acquired when the lizard is upon black rocks 

 but also when it is on red or brown rocks. 



