A Guide to the Amphibians
and Reptiles of California

Common Side-blotched Lizard - Uta stansburiana

Western Side-blotched Lizard - Uta stansburiana elegans

Yarrow, 1882

Click on a picture for a larger view

Description • Taxonomy • Species Description • Scientific Name • Alt. Names • Similar Herps • References • Conservation Status

Side-blotched Lizards California Range Map

Red: Range of this subspecies in California
Uta stansburiana elegans - Western Side-blotched Lizard

Dark Blue: Range of the other subspecies in California
Uta stansburiana nevadensis -Nevada Side-blotched Lizard

Click on the map for a topographical view

Map with California County Names

Southwest Page

Adult male, San Diego County

Adult female, San Diego County

Adult male (top) and adult female (bottom) San Benito County

Adult female, San Diego County

Adult male, San Benito County

The "side blotch" - a dark mark on the sides behind the front legs - gives this species its common name.

Adult male with regrown tail,
southern Inyo County

Adult male, San Bernardino County

Adult female, San Diego County

Adult male, San Luis Obispo County

Adult male, San Bernardino County

Adult female, southern Inyo County

Adult male, Santa Cruz County

Adult male, San Diego County

Colorful adult male, San Bernardino County © Guntram Deichsel

Adult, Santa Clara County (east of Mt. Hamilton) © Jon Hirt

Adult male with orange throat,
San Diego County

Adult female, Kern County

Adult male, San Luis Obispo County

Adult male, San Diego County

Adult male, Kern County

Adult, San Diego County

Male with yellow throat, Kern County desert

Adult female, western Riverside County

Adult male, southern Inyo County

Adult female, western Kern County

Adult male, San Diego County

Orange-throated adult male,
San Bernardino County

Adult female, Monterey County
© Bo Zaremba

Adult male showing the characteristic black blotch on the side and a colored throat, Alameda County

Adult male, Los Angeles County

Adult female, southern Inyo County

Adult male, San Diego County

Adult male, San Luis Obispo County

Adult female, San Bernardino County

Adult male, Santa Cruz County

Adult, southern Inyo County

Adult found under a rock in December in Alameda County © Noah Morales

Adult female, San Benito County
© Holly Lane

Adult male, southern Inyo County
© Yuval Helfman

Adult female, Kern County

Adult male, Inyo County

Adult male, Santa Cruz Island, Santa Barbara County

Adult, Santa Cruz Island
© Steve Bird

Adult male, Santa Barbara County
© Jen Castle

Adult, San Luis Obispo County
© Joel A. Germond

Adult male, Contra Costa County
© Kevin Hintsa

This picture shows the difference in color and pattern (not size) between an adult female Side-blotched lizard (above) and juvenile Western Fence Lizards (below.) © Mark Miller

The Side-blotched Lizards, genus Uta, have small keeled spineless scales on the back.

Sometimes the light markings on the sides of the back form two distinct longitudinal sripes (usually on females.)

Distinctly striped juvenile,
San Diego County desert
© Patrick Randall

Adult female with wide stripes,
San Bernardino County
© Guntram Deichsel

Striped adult female from
San Bernardino County
© Bo Zaremba

Striped adult female,
Kern County desert

Striped adult female,
San Bernardino County desert

Striped gravid female,
Riverside County © Jim Brock

Adult female with wide stripes,
San Bernardino County desert

Striped adult female, Santa Catalina Island © Nathan Smith

Uncommon or Interesting Patterns and Colors

Orange-sided adult male, San Diego County

Adult male with yellow sides,
San Diego County. © Jeffrey Belotti

This bright orange and yellow adult male was photographed in early April on the Palos Verdes Peninsula, Los Angeles County. © Sarah Ainsworth Photography

Patternless adult, San Joaquin County.
© Chad M. Lane

Patternless adult, Riverside County
© Nick Barrientos

Patternless adult female,
Riverside County © Adam Helbert

Riverside County patternless gravid adult female in center with a normally-patterned adult female on the left and a normally-patterned adult male on the right. © Adam Helbert

This apparently gravid Orange County female has bright orange coloring on her face and throat. Compare her to the male on her right. Like males, females can have orange, yellow, and blue throat coloring. Some orange-throated females are as colorful as the males. The photo was taken in late April. © Scott Shoemaker

Adult male with yellow sides,
San Bernardino County

Predation

scorpion eating Western Side-blotched Lizard

Side-blotched lizards are low on the food chain, falling prey to many predators, including this desert scorpion.
© Todd Battey

This juvenile Southern Pacific Rattlesnake was observed in Los Angeles County eating a Western Side-blotched Lizard that had been killed on a trail and was dead for some time before it was found by the snake, which took advantage of a free meal.
© Mark Rothenay

Breeding Behavior and Nesting

Mating adults, Los Angeles County
© Emily Chebul

Mating adults, Kern County
© John Sullivan

Mating adults, San Diego County © Douglas Brown

Mating adults, San Bernardino County
© Jeremiah Easter

A courting pair of adults in Orange County in May © Stacy Schenkel

Gravid adult female (top) and adult male (bottom) San Bernardino County.
© Kate Britsch

This gravid female side-blotched lizard was found apparently digging a nest in a San Diego County backyard in mid July.
© Connie McDowell

This is a short YouTube video of a gravid female side-blotched lizard apparently digging a nest in a San Diego County backyard in mid July. © Connie McDowell

In this short video a female side-blotched lizard in the San Diego County desert repeatedly goes in and out of a small hole under an exposed root, digging out the sand with her feet and pushing it lower with her body. It's the middle of the May breeding season, so maybe she is digging out a place to lay her eggs.

Habitat

Habitat, Mohave Desert,
San Bernardino County

Habitat, Alameda County grassland

Habitat, coastal Riverside County

Habitat, beach driftwood on Santa Cruz Island, Santa Barbara County

Habitat, San Diego County desert

Habitat, San Gabriel mountains chaparral, Los Angeles County

Habitat, Inyo County

Habitat, San Diego County desert canyon

Habitat, Carrizo Plain,
San Luis Obispo County

Chaparral / sandy wash habitat
San Benito County

Habitat, Santa Cruz Mountains,
Santa Cruz County

Habitat, Kern County

Habitat, Inyo County

Habitat, San Diego County

Short Videos

A male side-blotched lizard tries to pursuade a female, chasing her and displaying. She is not interested, so she runs off the rock into the San Diego County desert.

Common Side-blotched lizards in the Mohave Desert in San Bernardino County bask on rocks, do territorial push-ups and move around in the desert.

Walking through the San Bernardino County Mohave desert we discover several of these common lizards basking in the sun.

Description

Size

1.5 - 2.5 inches long from snout to vent (3.8 - 6.3 cm). (Stebbins 2003)

Appearance

A small brownish gray lizard with small smooth and spineless slightly keeled scales on the back, larger spineless keeled scales on the limbs and tail, a gular fold, and a long thin tail.

According to Brennan in Lizards of the American Southwest, this subspecies has an average of 91.3 dorsals (counting along the mid-dorsum from the interparietal scale to a point above the hind limbs) and more than 8 iterfemorals.

Color and Pattern

Color is brown, gray, yellowish, or black, with dark blotches, spots, and sometimes stripes.
Often there is a double row of dark spots or wedges on the back, edged with white on the rear.
The underside is whitish to gray and mostly unmarked.
The throat is mottled with dark and light.
A dark blue-black mark on the sides of the chest behind the front limbs gives this lizard its name.
This dark mark is sometimes faint or absent.

Male / Female Differences

Males are more colorful than females, having blue speckles on the upper surfaces, which are most visible during the light phase.
Males also have a swollen tail base and enlarged postanals, but no distinct blue coloring on the belly (which can be found on male lizards of many other species.)
The throat is marked with blue, orange, or yellow.
Males often have many blue speckles on the tail and the posterior of the body.

Females are blotched on top with brown and white, often with stripes, and have a less well-defined blotch on the sides.
They have no blue speckling, and no color on the throat.

Similar Subspecies

This subspecies is marked with a stronger dorsal pattern of spots and wedges than U. s. nevadensis, which has a more uniform dorsal pattern of scattered dark and light spots.

Three Male Color Morphs and Associated Behavior

Some fascinating discoveries have been made recently that show cooperative behavior with this species. Males have blue, orange, and yellow color morphs.
Researchers are calling this a "Rock-Paper-Scissors" game of male breeding strategies, because each color has an advantage over one other color, but not over both other colors.

Orange-throated males - are dominant, aggressive and territorial and mate with many different females.
Yellow-throated males - do not defend territories. They mimic females and sneak past territorial orange-throated males to mate with their females.
Blue-throated males- guard their mates, chasing off the yellow males, but they are run off when confronted by orange males. Blue males also cooperate with neighboring blue males to protect their respective mates from the orange and yellow males, and their breeding is much more successful when they do so.
(Sinervo and Zamudio, 2001)

Watch a video about this behavior: KQED Deep Look

Read more about this: MVZ UCSC

Life History and Behavior

Activity

Diurnal.
Active all year in the southern deserts and semi-arid regions whenever the temperature is warm. Inactive during cold weather.
It is active mostly on the ground, but a good climber.
Often seen basking on rocks, hopping from boulder to boulder, or running quickly along the ground.
The most abundant and commonly-seen lizard in the deserts and semi-arid areas.Usually the first lizard species out in the morning due to its small size which allows it to warm up quickly.
Often this lizard can be approached closely, since it relies on crypsis as a defence against predation, but when frightened it runs quickly into a burrow, under a surface object, or under vegetation.
The tail is often broken off when a lizard is captured, but it will grow back with time.

Longevity

This lizard is short-lived, living only about one year.

Territoriality

Males use a push-up display to display their territory.

Defense

The tail can break off easily, but it will grow back.
The detached tail wriggles on the ground which can distract a predator from the body of the lizard allowing it time to escape.
More information about tail loss and regeneration.

Diet and Feeding

Primarily insectivorous - eats small invertebrates such as beetles, grasshoppers, ants, spiders, scorpions and ticks.
Plant matter is sometimes eaten either for its water or by accident.

Reproduction

Mates in the spring.
1 - 7 clutches of 1 - 8 eggs are laid from March to August. (Stebbins 2003)
Females can store sperm to fertilize eggs at a later time.
Juveniles hatch from June to September, and breed the following spring.

Habitat

Prefers open rocky areas with scattered vegetation, including the edges of sandy washes. Utilizes a wide variety of habitats, including hardpan, sandy, rocky, and loamy areas grown with chaparral, scattered trees, grass, shrubs, and cactus.

Geographical Range

In California, this subspecies is found throughout the southern deserts and coastal region, north through the central valley and coast ranges to just south of the Bay Area, extending northward to the Sacramento River, and on Santa Cruz, Anacapa, San Clemente, and Catalina Islands.

The species ranges through most of California south of the Bay Area, all of Nevada, eastern Oregon, southwestern Idaho, central Washington, most of Utah, the western edge of Colorado, much of New Mexico the west part of Texas, north-central Mexico, along the west coast of Sonora, all of Baja California and many of its islands.

Elevational Range

From below sea level to around 9,000 ft. (2,700 m). (Stebbins 2003)

Notes on Taxonomy

The taxonomy of this widespread and variable species has been disputed.
Some experts do not recognize any subspecies of Uta stansburiana pending further studies that will provide more clarification about this species (which may consist of several different species).

Three subspecies of Uta stansburiana are sometimes shown occurring in California, including
U. s. stansburiana - Northern Side-blotched Lizard, which is shown to range east of the Sierra Nevada Mountains in Inyo and Mono counties.

Alternate and Previous Names (Synonyms)

Uta stansburiana - Common Side-blotched Lizard (Stebbins 2003)
Uta stansburiana - Side-blotched Lizard (Stebbins 1985)
Uta stansburiana hesperis - California Side-blotched Lizard (Stebbins 1966)
Uta stansburiana hesperis - Western Ground Uta (Smith 1946)
Uta stansburiana elegans - Desert Brown-shouldered Lizard (Uta elegans; Stansbury's Swift, part; Stansbury's Uta, part; Brown-shouldered Lizard, part) (Grinnell and Camp 1917)
Uta stansburiana hesperis - Southern Brown-shouldered Lizard (Stansbury's Swift, part; Stansbury's Uta, part) (Grinnell and Camp 1917)

Conservation Issues (Conservation Status)

None

Taxonomy
Family	Phrynosomatidae	Zebra-tailed, Earless, Fringe-toed, Spiny, Tree, Side-blotched, and Horned Lizards	Fitzinger, 1843
Genus	Uta	Side-blotched Lizards	Baird and Girard, 1852
Species	stansburiana	Common side-blotched lizard	Baird and Girard, 1852
Subspecies	elegans	Western side-blotched Lizard	Yarrow, 1882
Original Description
Uta stansburiana - Baird and Girard, 1852 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 69 Uta stansburiana elegans - Yarrow, 1882 - Proc. U.S. Natl. Mus., Vol. 5, p. 442 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Uta - state of Utah - refers to the region where it was first discovered. stansburiana - honors Stansbury, Howard S. elegans - Latin - fine or elegant from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Related or Similar California Lizards
U. s. nevadensis - Nevada Side-blotched Lizard
More Information and References
NatureServe Explorer USGS Male Uta cooperation and throat colors 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. Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021. Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018. 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. B. Sinervo and K. r. Zamudio. The Evolution of Alternative Reproductive Strategies: Fitness Differential, Heritability, and Genetic Correlation Between the Sexes. The Journal of Heredity 2001:92(2) Joseph Grinnell and Charles Lewis Camp. A Distributional List of the Amphibians and Reptiles of California. University of California Publications in Zoology Vol. 17, No. 10, pp. 127-208. July 11, 1917.

Conservation Status
The following conservation status listings for this animal are taken from the January 2024 State of California Special Animals List and the January 2024 Federally Listed Endangered and Threatened Animals of California list (unless indicated otherwise below.) Both lists are produced by multiple agencies every year, and sometimes more than once per year, so the conservation status listing information found below might not be from the most recent lists. To make sure you are seeing the most recent listings, go to this California Department of Fish and Wildlife web page where you can search for and download both lists: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. A detailed explanation of the meaning of the status listing symbols can be found at the beginning of the two lists. For quick reference, I have included them on my Special Status Information page. If no status is listed here, the animal is not included on either 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 also go to the NatureServe and IUCN websites to check their rankings. There are no significant conservation concerns for this animal in California.
Organization	Status Listing	Notes
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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