Field Guide to Reptiles
of Southern California
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Banded Rock Lizard (Petrosaurus mearnsi)
The banded rock lizard is restricted to the eastern slopes, canyons and rock-dominated desert flats of eastern San Diego and central Riverside cos., ranging up to 1050 m (3500 ft). It is most common in desert wash, palm oasis, and barren habitats. It prefers rock outcrops, boulder piles and canyon walls and is rarely found on the ground. No information is available on abundance, but it is possible to see several individuals in an area of less than 0.25 ha (0.63 ac) near Palm Springs. This species is active from mid-March until late summer (Stebbins 1954, Hain 1965, MacKay 1972).
This lizard lives almost exclusively on rock outcrops, boulder piles and canyon walls where it takes shelter under rocks, in cracks and crevices (Stebbins 1954, Hain 1965). This species occupies arid and semiarid habitats in the foothills and canyons along the western margin of the Colorado Desert. It is most frequently encountered in habitats dominated by rocks and canyon walls. This lizard moves about on the vertical and under surfaces of rocks, foraging with great agility.
Courtship begins shortly after emergence in early spring. Eggs are laid in June and July. Clutches range from 2-5 and average 3 eggs (Stebbins 1954, Hain 1965).
These are diurnal lizards that shuttle between sun and shade and are active all day even in hot weather. They usually become active by mid-March and remain active until the end of summer. In some years, late summer rains result in a period of fall activity (Stebbins 1954, Hain 1965, MacKay 1972). These lizards are not known to migrate.
Diet and Foraging
This lizard eats beetles, ants, bees, hemipterans, homopterans, flies, spiders and the buds of some plants (Stebbins 1954).
Home ranges were 85 m2 (930 ft2) for males and 40 m2 (440 ft2) for females in Deep Canyon, Riverside Co. (Carpenter 1962, Hain 1965, MacKay 1972, 1975). Male banded rock lizards defend territories but tolerate subadult males; females defend territories against other females (Carpenter 1962, Hain 1965).
Few potential predators could pursue this lizard over the surfaces it normally traverses. The young may be taken by Crotaphytus and avian predators.
Carpenter, C. C. 1962. A comparison of pattern os display of Urosaurus, Uta and Streptosaurus. Herpetologica 18:145-152.
Hain, M. L. 1965. Ecology of the lizard Uta mearnsi in a desert canyon. Copeia 1965: 78-81.
MacKay, W. P. 1972. Home range behavior of the banded rock lizard, Petrosaurus mearnsi. M. S. Thesis, California State Coll., Fullerton.
MacKay, W. P. 1975. The home range of the banded rock lizard Petrosaurus mearnsi (Iguanidae) Southwest. Nat. 20:113-120.
Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill, New York. 536pp.
Information gathered from California DFG - California Interagency Wildlife Task Group