Sceloporus occidentalis - Baird and Girard, 1852
Western Fence Lizard
Other English Common Names: western fence lizard
Taxonomic Status: Accepted
Related ITIS Name(s): Sceloporus occidentalis Baird and Girard, 1852 (TSN 173875)
Unique Identifier: ELEMENT_GLOBAL.2.106465
Element Code: ARACF14080
Informal Taxonomy: Animals, Vertebrates - Reptiles - Lizards
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Reptilia Squamata Phrynosomatidae Sceloporus
Genus Size: D - Medium to large genus (21+ species)
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Concept Reference
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Concept Reference: Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.
Concept Reference Code: B90COL01NAUS
Name Used in Concept Reference: Sceloporus occidentalis
Taxonomic Comments: Specific distinctness of S. occidentalis and S. undulatus is confirmed by their sympatric reproductive isolation in southwestern Utah (Cole 1983, Smith and Chiszar 1989). See Sites et al. (1992) for a review of phylogenetic hypotheses for lizards of the genus Sceloporus.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 20Jul2005
Global Status Last Changed: 28Oct1996
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5 (05Oct1996)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States California (SNR), Idaho (S5), Montana (SU), Nevada (S5), Oregon (S5), Utah (S3S4), Washington (S4)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: 200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Range Extent Comments: The range extends from Washington and southeastern Idaho south through Oregon, California, Nevada, and western Utah to northwestern Baja California (Bell and Price 1996, Grismer 2002, Stebbins 2003), and disjunctly south to Isla de Cedros (Grismer and Mellink, 1994, J. Herpetol. 28:120-126). Elevational range extends from sea level to about 11,000 feet (3,353 meters) (Bell and Price 1996, Stebbins 2003).

Number of Occurrences: > 300
Number of Occurrences Comments: This species is represented by hundreds of collection sites (e.g., see Nussbaum et al. 1983, Bell and Price 1996).

Population Size: 100,000 to >1,000,000 individuals
Population Size Comments: Total adult population size is unknown but certainly exceeds 100,000.

Number of Occurrences with Good Viability/Integrity: Very many (>125)

Overall Threat Impact: Medium
Overall Threat Impact Comments: No major threats have been identified. Locally, conversion of habitat to intensive human uses have eliminated or reduced some populations.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Extent of occurrence, area of occupancy, and population size are large and probably relatively stable (or slowly declining).

Long-term Trend: Decline of <30% to increase of 25%

Intrinsic Vulnerability: Moderately vulnerable

Other NatureServe Conservation Status Information

Distribution
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Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) The range extends from Washington and southeastern Idaho south through Oregon, California, Nevada, and western Utah to northwestern Baja California (Bell and Price 1996, Grismer 2002, Stebbins 2003), and disjunctly south to Isla de Cedros (Grismer and Mellink, 1994, J. Herpetol. 28:120-126). Elevational range extends from sea level to about 11,000 feet (3,353 meters) (Bell and Price 1996, Stebbins 2003).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States CA, ID, MT, NV, OR, UT, WA

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted.

Range Map Compilers: NatureServe, 2005


U.S. Distribution by County Help
State County Name (FIPS Code)
ID Ada (16001), Bingham (16011)*, Boise (16015)*, Canyon (16027)*, Cassia (16031)*, Elmore (16039), Gem (16045)*, Gooding (16047)*, Idaho (16049), Jerome (16053)*, Nez Perce (16069), Owyhee (16073), Twin Falls (16083), Washington (16087)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
17 American Falls (17040206)+*, Raft (17040210)+*, Goose (17040211)+*, Upper Snake-Rock (17040212)+, Salmon Falls (17040213)+*, C. J. Idaho (17050101)+, Bruneau (17050102)+, Middle Snake-Succor (17050103)+, South Fork Owyhee (17050105)+, East Little Owyhee. Nevada, (17050106)+*, Middle Owyhee (17050107)+, Jordan (17050108)+, Boise-Mores (17050112)+*, South Fork Boise (17050113)+*, Lower Boise (17050114)+*, Payette (17050122)+*, Weiser (17050124)+, Lower Snake-Asotin (17060103)+, Middle Salmon-Chamberlain (17060207)+, Lower Salmon (17060209)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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General Description: The scales on the back are fairly large, keeled, and pointed. Coloration is highly variable, but often the back is gray, brown, or black, with a series of wavy dark and light bands across the back or a row of somewhat V-shaped dark blotches along each side of the back. ; rear of thigh yellow or orange; scales on rear of thigh mostly keeled; up to 3.9 inches (9.9 cm) snout-vent length. Breeding males have a blue patch on the throat (sometimes partially divided), a blue black-edged patch on each side of the belly (in some areas there may be a single large blue patch on the belly), sometimes blue or greenish scales on the back, a pair of enlarged scales behind the vent, and two swellings from hemipenes (copulatory organs) on the underside of the tail base. Breeding females and small young lack blue scales on the back, and the blue markings on the underside are faint or absent; they also lack enlarged scales behind the vent and have no swellings at the tail base.
Reproduction Comments: Courtship and mating generally occur in spring. Egg laying extends from April or May to June or July in most areas. Eggs are buried in loose soil or secluded in old logs or under rocks. Clutch size in different areas ranges from 3 to 17; clutch size tends to increase with female size, latitude, and elevation. Eggs hatch in about 2 months, mostly in August or September in many areas. Individuals first breed in the spring of their second year (Nussbaum et al. 1983, Stebbins 1985).
Ecology Comments: Adult males defend home range during breeding season. Seasonal home range generally much less than 0.01 ha in central California (Davis and Ford 1983). Predators: predatory birds and snakes.

When individuals on tree trunks are approached closely, they often move to the other side of the trunk.

Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Palustrine Habitat(s): Riparian
Terrestrial Habitat(s): Bare rock/talus/scree, Cropland/hedgerow, Grassland/herbaceous, Savanna, Shrubland/chaparral, Woodland - Conifer, Woodland - Hardwood, Woodland - Mixed
Special Habitat Factors: Burrowing in or using soil, Fallen log/debris, Standing snag/hollow tree
Habitat Comments: This lizard occupies various habitats, including grassland, sagebrush, woodland, open coniferous forest, rocky canyons, talus slopes, fence rows, etc. (Stebbins 2003). This species is not found in severe desert areas, but it comes close on mountain slopes (Stebbins 2003). Usually it is on the ground or on low perches (e.g., logs, fences), but sometimes climbs well up into taller bushes or trees. Eggs are buried in loose soil.
Adult Food Habits: Invertivore
Immature Food Habits: Invertivore
Food Comments: Eats mainly insects (e.g. beetles, flies, caterpillars, and ants) and spiders.
Adult Phenology: Diurnal, Hibernates/aestivates
Immature Phenology: Diurnal, Hibernates/aestivates
Phenology Comments: These lizards are generally inactive during cold weather. Duration of the inactive period varies with local climate. Emergence from hibernacula occurs in late winter or early spring, depending on local conditions.
Length: 24 centimeters
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation
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Group Name: Phrynosomatid Lizards

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals (including eggs) in or near appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Busy highway or highway with obstructions such that lizards rarely if ever cross successfully; major river, lake, pond, or deep marsh; urbanized area dominated by buildings and pavement.
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Phrynosomatid lizards have small home range sizes, usually less than 0.5 ha (often much less) and rarely more than 1 ha (see examples in BCD EO Specs). In a study that documented exceptionally large home range size for a phrynosomatid, Munger (1984a) found that single-season home range size of Phrynosoma cornutum in southern Arizona averaged less than 2.5 ha. Dispersal distances are poorly known, and most studies have not been designed to detect long distance movements. The separation distance for suitable habitat is a compromise between the typical sedentary habits of these lizards, their physical ability to cover fairly large distances in a short period of time, their tendency to occur throughout patches of suitable habitat, and the likely low probability that two occupied locations separated by less than several kilometers of suitable habitat would represent independent populations.
Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .2 km
Date: 21Sep2004
Author: Hammerson, G.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 20Jul2005
NatureServe Conservation Status Factors Author: Hammerson, G.
Element Ecology & Life History Edition Date: 28Jan2010
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.

  • Bell, E. L., and A. H. Price. 1996. SCELOPORUS OCCIDENTALIS. Catalogue of North American Amphibians and Reptiles 631.1-631.17.

  • Brown, H. A., R. B. Bury, D. M. Darda, L. V. Diller, C. R. Peterson, and R. M. Storm. 1995. Reptiles of Washington and Oregon. Seattle Audubon Society, Seattle, Washington. viii + 176 pp.

  • Cole, C. J. 1983. Specific status of the North American fence lizards, SCELOPORUS UNDULATUS and SCELOPORUS OCCIDENTALIS, with comments on chromosome variation. Am. Mus. Novitates (2768):1-13.

  • Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.

  • Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84. Online with updates at: http://www.ssarherps.org/pages/comm_names/Index.php

  • Crother, B. I. (editor). 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 7th edition. SSAR Herpetological Circular 39:1-92.

  • Davis, J., and R. G. Ford. 1983. Home range of the western fence lizard (SCELOPORUS OCCIDENTALIS OCCIDENTALIS). Copeia 1983:933-940.

  • Grismer, L. L. 2002. Amphibians and reptiles of Baja California including its Pacific islands and islands in the Sea of Cortes. University of California Press, Berkeley. xiii + 399 pp.

  • Nussbaum, R.A., E.D. Brodie, Jr., and R.M. Storm. 1983. Amphibians and Reptiles of the Pacific Northwest. University Press of Idaho, Moscow, Idaho. 332 pp.

  • Schwinn, M. A., and L. Minden. 1980. Utah reptile and amphibian latilong distribution. Publ. No. 80-1. Utah Division of Wildlife Resources, Salt Lake City, Utah.

  • Sinervo, B. 1990. The evolution of maternal investment in lizards: an experimental and comparative analysis of egg size and its effects on offspring performance. Evolution 44:279-294.

  • Sites, J. W., Jr., J.W. Archie, C.J. Cole and O. Flores-Villela. 1992. A review of phylogenetic hypotheses for lizards of the genus Sceleporus (Phrynosomatidae): implications for ecological and evolutionary studies. Bull. Am. Mus. Nat. Hist. (213):1-110.

  • Smith, H. M., and D. Chiszar. 1989. The subspecific identity of the population of SCELOPORUS UNDULATUS sympatric with S. OCCIDENTALIS. Bull. Maryland Herp. Soc. 25(4):143-150.

  • St. John, A. 2002. Reptiles of the northwest. Lone Pine Publishing, Renton, Washington. 272 pp.

  • Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.

  • Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. Third edition. Houghton Mifflin Company, Boston.

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