General Distribution
The western fence lizard is probably California's most common reptile. This adaptable
lizard is found throughout California except in true desert, where it is restricted to riparian and
high mountain locations. Elevation sea level to 3250 m (10,000 ft). Habitat Requirements
Basking or perching sites (usually tree trunks, woodpiles, wooden fences, rock
piles, or walls of buildings) with some vertical element appear to be an important habitat
factor. When pursued, individuals seek cover by running to the opposite side of their perch
(Nussbaum et al. 1983), or take refuge in crevices or burrows, or under surface objects such
as rocks or boards. Tree bark (Gray and Stroud 1980), rocks, and boards, as well as
crevices and burrows, serve as hibernation sites during cold periods. Reproduction
Courtship in captive individuals has been observed as early as March and
April (Fitch 1940), and copulations have been witnessed in May and June (Davis 1980). The
interval between copulation and egg-laying is probably from two weeks to a month. Eggs are
deposited mid-May to mid-July (Stebbins 1954) and the incubation period (Davis 1980) is
about 60 days. Daily/Seasonal Activity
Activity is almost exclusively diurnal. Nussbaum et al. (1983) noted
some nocturnal activity during warm periods. The length of warm season activity varies
geographically, but in most localities fall and winter inactivity occurs. Juveniles appear active
later in the fall than adults. Diet and Foraging
Western fence lizards have been shown by Johnson (1965), Rose (1976a), and
others, to feed almost exclusively on terrestrial invertebrates, especially insects. Spiders,
ticks, scorpions, centipedes, and isopods are taken less frequently. Cannibalism has also
been reported. Territoriality/Home Range
Home range sizes vary geographically and in response to resource
abundance. Tanner and Hopkin (1972) calculated home ranges for fence lizards in an open
shrub habitat in Nevada as 0.2-0.7 ha (0.6-1.7 ac) for males, and 0.04-0.2 ha (0.1-0.5 ac) for
females. At Mt. Diablo in central California, Ruth (1977) calculated fence lizard densities at
22-33/ha (8.9-13.4/ac). During spring, males defend a loosely defined territory of up to 7.5 m (25 ft)
radius. The territory is defended less vigorously as summer progresses. Territorial defense
is accomplished by posturing and physical combat. Predator-Prey Relations
Western fence lizards are important prey items for a variety of vertebrate
species including snakes (Fitch 1940) and predatory birds. Nussbaum et al. (1983) report
that shrews occasionally feed or dormant fence lizards. Literature Cited
Davis, J. 1980. The times of mating and oviposition fo the western fence lizard, Sceloporus
occidentalis occidentalis. J. Herpetol. 14:102.
Fitch, H. S. 1940. A field study of the growth and behavior of the fence lizard. Univ. Calif.
Publ. Zool. 44:151-172.
Gray, R. L., and D. C. Stroud. 1980. A winter aggregation of the western fence lizard,
Sceloporus occientalis. J. Herpetol. 14:103.
Johnson, C. R. 1965. The diet of the Pacific fence lizard, Sceloporus occidentalis
occidentalis (Baird and Girard), from northern California. Herpetologica 21:114-117.
Nussbaum, R. A., E. D. Brodie, Jr., and R. M. Storm. 1983. Amphibians and reptiles of the
Pacific Northwest. Univ. Press of Idaho. 332pp.
Rose, B. R. 1976a. Dietary overlap of Sceloporus occidentalis and Sceloporus graciosus.
Copeia 1976:818-820.
Rose, B. R. 1976b. Habitat and prey selection of Sceloporus occidentalis and Sceloporus
graciosus. Ecology 57:531-541.
Ruth, S. B. 1977. A comparison of the demography and female reproduction in sympatric
western fence lizards (Sceloporus occidentalis) and Sagebrush Lizards (Sceloporus
graciousus) on Mount Diablo, Calif. Ph.D. Thesis, Univ. California, Berkeley. 195pp.
Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill,
New York. 536pp.
Tanner, W. W., and J. M. Hopkin. 1972. Ecology of Sceloporus occidentalis longipes Baird
and Uta stansburiana Baird and Girard on Ranier Mesa, Nevada Test Site, Nye County,
Nevada. Brigham Young Univ. Sci. Bull. Bio. Ser. 15:1-39.
Information gathered from California DFG - California Interagency Wildlife Task Group
