CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Northwestern Fence Lizard - Sceloporus occidentalis occidentalis

Baird and Girard, 1852
Click on a picture for a larger view



Western Fence Lizards California Range Map Range in California: Red

Click the map for a guide to the other subspecies.



observation link





Northwestern Fence Lizard
Adult male, Trinity County
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Calaveras County Adult female, Trinity County
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male from Tule Lake, Siskiyou County Adult female, Siskiyou County Adult female, Siskiyou County
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, El Dorado County  Adult male, Siskiyou County Adult male, Siskiyou County
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Humboldt County    Adult female, Solano County Recent hatchling, August, Maury Island, King County, Washington
© Steven Caldwell
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Butte County Juvenile, Sierra County Adult, Lake County © Gary Beach
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Solano County Adult, Sonoma County Adult male, Tulare County
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Merced County Del Norte County, © Alan Barron Adult female, Sutter County
© Jackson Shedd
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Siskiyou mountains, Siskiyou County  Adult male, Sutter Buttes, Sutter County.
© Jackson Shedd.
Specimen courtesy of Eric Olson.
Adult male, Sutter County
© Jackson Shedd
Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard Northwestern Fence Lizard
Dark phase adult male, Del Norte County Adult male, Trinity County
Northwestern Fence Lizard Northwestern Fence Lizard
Adult, in dark phase before warming up, Humboldt County © Dylan Gross

Sometimes fence lizards are very dark before they have warmed up in the sun. They can look like they're completely black at a distance.
Adult male, Sonoma County Adult male, Butte County,
 defecating.

Juveniles, Stanislaus County © Joe Lovell
Northwestern Fence Lizard Northwestern Fence Lizard
Adult male, Stanislaus County © Joe Lovell Adult female, Siskiyou County Adult female, Siskiyou County
Northwestern Fence Lizard lizard Gilbert Skink and Fence Lizard
This adult male intergrade or hybrid from Yosemite Valley in Mariposa County is extremely blue. © John Aylward, www.GreatOutdoorImages.com Adult female, Siskiyou County Two adult males squared off and showing each other their colors and bodies in a territorial dispute in Lake County. © Kathleen Scavone

This adult male Northwestern Fence Lizard and adult male Greater Brown Skink were photographed basking together in Placer County in late April
© Rod

lizard skin  
Adult female, Stanislaus County © Joe Lovell Western Fence Lizards have overlapping keeled scales with spines on them over much of their body.  
       
Predation and Parasites
spider eating fence lizard California Striped Racer eating a male Great Basin Fence lizard California Striped Racer eating a male Great Basin Fence lizard California Striped Racer eating a male Great Basin Fence lizard
Juvenile fence lizards are preyed upon by many other animals, including the black widow spider. © Rory Doolin Sean Kelly © shot this series of a California Striped Racer eating a male Great Basin Fence lizard in San Diego County.
California Striped Racer Pacific Gopher Snake eating a Western Fence Lizard Pacific Gopher Snake eating a Western Fence Lizard California Striped Racer
California Striped Racers eat mosly lizards. This one is swallowing a Western Fence Lizard while holding the front third of its body straight up off the ground. This racer usually hunts with its head in this elevated position. Juvenile Pacific Gopher Snake eating a Western Fence Lizard © Daniel Harris A California Striped Racer swallows a male Northwestern Fence Lizard in
El Dorado County © Jim Bennett
fence lizard with ticks Speckled Rattlesnake Speckled Rattlesnake  

Adult male with ticks on the side of his head.

In California, western black-legged ticks (deer ticks) are the primary carriers of Lyme disease. Very tiny nymphal deer ticks are more likely to carry the disease than adults. A protein in the blood of Western Fence Lizards kills the bacterium in these nymphal ticks when they attach themselves to a lizard and ingest the lizard's blood. This could explain why Lyme disease is less common in California than it is in some areas such as the Northeastern states, where it is epidemic.

More Information

Sean Kelly found this juvenile Southwestern Speckled Rattlesnake eating a Great Basin Fence Lizard behind his garbage can one afternoon in San Diego County.
© Sean Kelly
 
     
Habitat
Northwestern Fence Lizard Habitat Northwestern Fence Lizard Habitat Northwestern Fence Lizard Habitat Northwestern Fence Lizard Habitat
Habitat, Mendocino County Habitat, El Dorado County Habitat, Calaveras County Habitat, Shasta County
Northwestern Fence Lizard Habitat Northwestern Fence Lizard Habitat
Northwestern Fence Lizard Habitat
Northwestern Fence Lizard Habitat
Habitat, Smith River, Del Norte County Habitat, lava beds, Siskiyou County Habitat, Butte County Habitat, Trinity County
Northwestern Fence Lizard Habitat Northwestern Fence Lizard Habitat    
Habitat, Solono County Habitat, Siskiyou County    
       
A California Western Fence Lizard Travels to Germany
Western Fence Lizard Western Fence Lizard    
The lizard shown directly above was found in a freight container containing only metal boxes at the BMW plant in Dingolfing / Bavaria / Germany on Oct 17, 2006. The container was shipped from Stockton CA on Sep 14, 2006. The lizard survived a 33 day voyage without food and water. The container was placed most likely on the top deck of the vessel and hence cooled down considerably at night which explains the good condition of the animal upon arrival.

Photos © Jochen Späth
Information: Guntram Deichsel


Many species of plants and animals have been introduced into areas of the planet where they did not naturally evolve. The journey of this lizard illustrates one way animals can spread around the globe: If the lizard was a gravid female who found conditions favorable to her survival once she arrived, laid her eggs, and eventually the offspring began reproducing, or if other lizards arrived at the same location and bred with her, then an established breeding population could develop.
 
Short Videos of Northwestern Fence Lizards
   
A male Northwestern Fence Lizard defecates off the side of a Butte County fence, wipes himself off, then does a territorial push-up display. I'm not going out of my way trying to film this behavior - I can only take what I get - so here we see another Northwestern Fence Lizard doing his business for the camera. It's like they're trying to tell me something. A male Northwestern Fence Lizard fights with a female in Placer County © Rod  
   
These two videos show a Placer County Northwestern Fence Lizard appearing to taunt a garter snake (a Mountain Gartersnake is my guess, because it lacks red.) The lizard keeps moving down towards the snake but when the snake moves towards the lizard, apparently trying to catch it for dinner, the lizard runs up the wall away from the snake. © Rod    
 
Short Videos of Other Subspecies of Western Fence Lizard
Sierra Fence Lizard Sierra Fence Lizard Great Basin Fence Lizard San Joaquin Fence Lizard
Sierra Fence lizards run around a rocky area in the woods 8,000 ft. high in the Sierra Nevada mountains. A Sierra Fence Lizard, or intergrade, runs around rocks in the forest up at 5,600 ft. in Tuolumne County. A male fence lizard in Inyo County defensively showing his throat color and doing push-ups.

San Joaquin Fence Lizards on trees along a river in early spring.

Coast Range Fence Lizard Coast Range Fence Lizard Coast Range Fence Lizard
A few fence lizards in Contra Costa County. A male fence lizard on a tree in Alameda County. Several juvenile fence lizards come out to bask in the sun on a cool and windy morning in early March. Two Coast Range Fence Lizards, Sceloporus occidentalis bocourtii, are observed during the breeding season in early May in San Benito County. The first lizard, a female, has moved from her perch on a rock to a nearby rock in order to get away from the photographer. She begins a territorial push-up display when a male comes up the side of the rock and begins to pursue her. She arches her back and hops away in order to reject him. She may have already mated and is bearing eggs, or maybe he is not her type. He finally stops and does a push-up display, possibly to continue trying to entice her, or possibly to warn the photographer that this is his territory.

Great Basin Fence Lizard Great Basin Fence Lizard    
A female fence lizard runs across a wall in Riverside County and encounters a male who pursues her. She rejects him and he runs to an open spot on top of the wall and does a push-up display. Large, dark phase Great Basin Fence Lizards bask and eat ants off rocks in Inyo County.
   
     
Description
 
Size
2.25 - 3.5 inches long from snout to vent (5.7 - 8.9 cm). (Stebbins 2003)

Appearance
A fairly small lizard with keeled and pointed dorsal scales of equal size on the back, sides, and belly.
Scales on the backs of the thighs are mostly keeled, and abruptly smaller.
Color and Pattern
Color is brown, gray, or black with blotches.
Sometimes light markings on the sides of the backs form stripes or irregular lines, and sometimes dark blotching may form irregular bands.
The rear of the limbs is yellow or orange.
The sides of the belly are blue.
The belly is light in color.
Male / Female Differences
Males have blue markings on the sides of the belly edged in black, two blue patches on the throat, often connected with a light band, enlarged postanals,
enlarged femoral pores, and a swollen tail base.
Some scales on a male's back become blue or greenish when he is in the light phase.

Females have faint or absent blue markings on the belly, no blue or green color on the upper surfaces, and dark bars or crescents on the back.
Young
Juveniles have little or no blue on the throat and faint blue belly markings or none at all.
 
Differences Between the Western Fence Lizard and the Similar Sagebrush Lizard in California
 
Life History and Behavior

Activity
Diurnal.
Often seen basking in the sun on rocks, downed logs, trees, fences, and walls.
Prefers open sunny areas.
Active when temperatures are warm, becomes inactive during periods of extreme heat or cold, when they shelter in crevices and burrows, or under rocks, boards, tree bark, etc.

Common and easily encountered in the right habitat.
This is probably the species of lizard most often seen in the state due to its abundance in and near populated areas and its conspicuous behavior.
Territoriality
Males establish and defend a territory containing elevated perches where they can observe mates and potential rival males.
Males defend their territory and try to attract females with head-bobbing and a push-up display that exposes the blue throat and ventral colors. Territories are ultimately defended by physical combat with other males.
Defense
The tail detaches easily to distract a potential predator allowing the lizard to escape.
Diet and Feeding
Eats small, mostly terrestrial, invertebrates such as crickets, spiders, ticks, and scorpions, and occasionally eats small lizards including its own species.
Breeding
Mates in early to late spring, depending on the elevation of the location.

Courtship and copulation typically occurs from March to June.
Egg laying occurs 2 - 4 weeks after copulation.
Females dig small pits in loose damp soil where they lay 1 - 3 clutches of 3 - 17 eggs usually from May to July.
Eggs hatch in about 60 days, usually from July to September.

Western Fence Lizards and Lyme Disease
In California, western black-legged ticks (deer ticks) are the primary carriers of Lyme disease. Very tiny nymphal deer ticks are more likely to carry the disease than adults. A protein in the blood of Western Fence Lizards kills the bacterium in these nymphal ticks when they attach themselves to a lizard and ingest the lizard's blood. This could explain why Lyme disease is less common in California than it is in some areas such as the Northeastern states, where it is epidemic.

More Information: (Berkeleyan April 1998)


In an interesting twist, UC Berkeley researchers have found that when fence lizards are removed from an area, the population of Lyme disease-carrying ticks plummets. Up to 90 percent of juvenile Western black-legged ticks, the species that carries the Lyme disease bacteria, feed on Western Fence Lizards. When lizards are no longer available, 95 percent of the ticks fail to find another host to feed on.

More Information: (Berkeley News February 2011)

Habitat
Found in a wide variety of open, sunny habitats, including woodlands, grasslands, scrub, chapparal, forests, along waterways, suburban dwellings, where there are suitable basking and perching sites, including fences, walls, woodpiles, piles of rocks and rocky outcrops, dead and downed trees, wood rat nests, road berms, and open trail edges.

Geographical Range
This subspecies ranges from north and east of the San Francisco Bay Area north into, Oregon, and Washington.

The species Sceloporus occidentalis ranges from northern Baja California north to Washington and east to Idaho, Nevada and Utah.

The ranges of subspecies shown on the range map above are based mostly on Ryan Calsbeek's distribution map.

Full Species Range Map
An alternate interpretation of the ranges of S. o. longipes and S. o. occidentalis showing S. o. occidentalis present in northeastern California and central Oregon instead of S. o. longipes can be seen here.

Elevational Range
The species Sceloporus occidentalis - Western Fence Lizard, is found at elevations from sea level to around 10,800 ft.
(3,300 m.) (Stebbins, 2003)

Notes on Taxonomy
The taxonomy of Sceloporus occidentalis needs to be studied further. For years six subspecies have been recognized based on geographic variation in morphology, but molecular studies have identified 4 major clades and 11 different genetic groups in California (James Archie, Cal State University Long Beach).

Many authorities have already accepted research that concludes that S. o. becki, the Island Fence Lizard, is a unique species - Sceloporus becki. (Wiens & Reeder, 1997) (Bell, 2001) Others have shown that S. o. taylori should not be classified as a distinct subspecies.

The current taxonomy does not correspond with the ongoing research, so it is certain that in the future the current subspecies and their ranges will be completely revised, probably with several new species described. For this reason some experts no longer recognize any subspecies of S. occidentalis pending further studies. This site follows the SSAR list of 2008 and continues to recognize 6 subspecies.


Alternate and Previous Names (Synonyms)

Commonly called: Bluebelly, Blue-bellied Lizard, Fence Lizard, Swift, Fence Swift

Sceloporus occidentalis - Western Fence Lizard (no subspecies recognized) (Stebbins 2003)
Sceloporus occidentalis occidentalis - Northwestern Fence Lizard (Stebbins 1966, 1985)
Sceloporus occidentalis occidentalis - Pacific Fence Lizard (Smith 1946)

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Phrynosomatidae Zebra-tailed, Earless, Fringe-toed, Spiny, Tree, Side-blotched, and Horned Lizards Fitzinger, 1843
Genus Sceloporus Spiny Lizards Wiegmann, 1828
Species occidentalis Western Fence Lizard Baird and Girard, 1852
Subspecies

occidentalis Northwestern Fence Lizard Baird and Girard, 1852
Original Description
Sceloporus occidentalis - Baird and Girard, 1852 - Prox. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 175

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Sceloporus - Greek -skelos leg and porus - pore or opening - refers to the femoral pores on hind legs
occidentalis
- Latin - western - refers to its western distribution

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Lizards
Western Fence Lizards:
Sceloporus occidentalis becki - Island Fence Lizard
Sceloporus occidentalis biseriatus - San Joaquin Fence Lizard
Sceloporus occidentalis bocourtii - Coast Range Fence Lizard
Sceloporus occidentalis longipes - Great Basin Fence Lizard
Sceloporus occidentalis taylori - Sierra Fence Lizard

Sagegrush Lizards:
S. graciosus graciosus - Northern Sagebrush Lizard
S. graciosus gracilis - Western Sagebrush Lizard
S. graciosus vandenburgianus - Southern Sagebrush Lizard

More Information and References
California Department of Fish and Wildlife

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Jones, Lawrence, Rob Lovich, editors. Lizards of the American Southwest: A Photographic Field Guide. Rio Nuevo Publishers, 2009.

Smith, Hobart M. Handbook of Lizards, Lizards of the United States and of Canada. Cornell University Press, 1946.

Brown et. al. Reptiles of Washington and Oregon. Seattle Audubon Society,1995.

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

St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. Lone Pine Publishing, 2002.

Wiens & Reeder (1997 Herpetological Monographs 11: 1-101)

Bell (2001 Bulletin of the Maryland Herpetological Society 37(4): 137-142)

S. Morey. Western Fence Lizard Family: Phrynosomatidae R022. California Wildlife Habitat Relationships System California Department of Fish and Game. Originally published in Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990.


Conservation Status

The following status listings are copied from the 2017 Special Animals List and the 2017 Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.

If no status is listed here, the animal is not included on either CDFW list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status, you can go to the NatureServe and IUCN websites to check their rankings.

Check here to see the most current complete lists.


This animal is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.


Organization
Status Listing
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None
IUCN

 

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