CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Baja California Brush Lizard - Urosaurus nigricaudus

(Cope, 1864)
Click on a picture for a larger view



Baja California Brush Lizard California Range Map
Range in California: Red

Dot-locality Range Map




observation link





Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard
  Adult male, San Diego County   Adult male, San Diego County
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard
  Adult female, San Diego County   Adult male, San Diego County
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard
  Adult male, San Diego County  
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard
  Adult female, San Diego County  
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard
  Adult female, San Diego County  
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizards
Adult male, San Diego County Adult male, San Diego County, showing the black tail that gives this species its name. Adult males in combat, showing off their bright throat and ventral colors as a warning, San Diego County.These lizards were observed chasing and biting each other around the surface of a large boulder, paying little attention to me as I got close to them. Bite marks are visible on the tail of the lizard on the left.
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard  
Adult, Imperial County © Brian Hubbs Adult, San Diego County © Dave Goodward  
       
Comparison with Similar Sympatric Species
There are two other similar species of lizards that are found in California, but only the Western Long-tailed Brush Lizard shares part of its range with the California Brush Lizard. The Tree Lizard has spread beyond its range into some areas and could possibly be found in the range of the California Brush Lizard so it is included here.
The three species can be separated best by looking at the wide band of enlarged scales on the middle of the back that is found on each species.

black tailed brush lizard scales Baja California Brush Lizard Long-tailed Brush Lizard Colorado River Tree Lizard
The Baja California Brush Lizard has a mixture of small granular scales and larger weekly-keeled scales on the dorsal surface.

The band of enlarged weekly-keeled scales is not split in the center by smaller scales.
The Western Long-tailed Brush Lizard has a band of slightly-enlarged scales on the middle of the back that are not split in the center by smaller scales, but the enlarged scales are smaller than those of the Long-tailed Brush Lizard. The band of wide weekly-keeled scales on the back of a tree lizard is split in the center by smaller scales.

The lizard shown above is not the
U. o. symmetricus
subspecies that is native to California which has a wider band of small scales than the subspecies illustrated here. I don't have a close-up of that subspecies. If you do, send it in, I'll use it!
fence lizard scales side-blotched lizard scales Western Side-blotched Lizard  
Western Fence Lizards and Sagebrush lizards have large overlapping scales with spines on the back. The Western Side-blotched Lizard - Uta stansburiana elegans - has small scales on the back with no band of enlarged scales in the middle, and typically has a large dark blotch on the sides behind the front legs.
 
Baja California Brush Lizards fence lizard and sagebrush lizard comparison    
Undersides of female (left)
and male (right) Black-tailed Brush Lizards from San Diego County.

Both sexes of U. nigricaudus have a patch of orange or yellow or both colors on the throat. Males have an almost solid blue belly. © Stuart Young
Western Fence Lizard on the left, Common Sagebrush Lizard on the right.

Males of both species have blue, not yellow or orange on the throat and split bands of bright blue color on the belly. The fence lizard also has yellow on the backs of the thighs. © Patrick Briggs
   
       
Habitat
Baja California Brush Lizard Habitat Baja California Brush Lizard Habitat Baja California Brush Lizard Habitat Baja California Brush Lizard Habitat
Habitat San Diego County
Habitat, palm oasis, San Diego County
Habitat, San Diego County
Baja California Brush Lizard Habitat Baja California Brush Lizard Habitat Baja California Brush Lizard Habitat  
Habitat San Diego County
Habitat San Diego County
Habitat Imperial County
 
 
Short Videos
Baja California Brush Lizard Baja California Brush Lizard Baja California Brush Lizard noosing  
Some good looks at a camera-tolerant female brush lizard before she bolts, with some impressive tail wagging. A female brush lizard does a few push-up displays and some tail wagging. This video shows how to noose a lizard. Notice the lizard's defensive push-up behavior towards the noose. After a missed attempt, Stuart finally gets the noose around the lizard's neck and pulls him off the rock, being careful not to injure him. It's a colorful male Baja California Brush Lizard. After we admire him, he is put back on his boulder.  
     
Description
 
Size
1.5 - 2 inches long from snout to vent (3.8 - 5.1 cm). (Stebbins 2003)

Appearance
A small, lizard with a long, thin tail.
Scales are small and granular with a band of enlarged keeled scales down the middle of the back.
Scales on the tail are keeled.
Gular fold across the throat, and folds along the sides of the body.
The tail detaches easily and regenerates.
Color and Pattern
Color is gray, brown, or sooty, with dark blotches or crossbars on the back, sometimes edged with light coloring or white spots.
The tail is usually black, especially on males.
The dark color is more noticeable when a lizard's body is in the light phase.
(Lizards west of the mountains often do not have a black tail. [Lemm 2006])
Sometimes there is an irregular gray or brown stripe down the middle of the back.
The tail, upper sides, and neck are sometimes marked with rust or yellow-brown coloring.
The underside is light yellow-gray or white, sometimes with darker coloring under the tail.
Male / Female Differences
Males have yellow or orange in the middle of the throat, which can be blue, and blue to blue-green patches on the belly, which may connect in the center, and enlarged postanal scales.

Females have a yellow, orange, or white throat, with no blue on the belly.

Life History and Behavior

Activity
A good climber.
Moves quickly from rock to rock.
Active spring and summer and sometimes in fall, hibernating in winter with groups of other lizards.
Territoriality
Males defend their territory and try to attract females with head-bobbing and a push-up display that exposes their throat and ventral colors.
Females also do a push-up display .
Defense
The dark tail may serve to distract a predator to an expendable body part.
The tail is easily detached and when detached wriggles for several minutes which may distract a predator from the lizard long enough for it to escape.
Diet and Feeding
Eats small invertebrates.
Breeding
Breeds April through summer.
1 - 2 clutches of 4 - 8 eggs are laid June to August and possibly as late as September.

Geographical Range
Inhabits both sides of the Peninsular ranges in San Diego County south to the southern tip of Baja California.
Found from Borrego Palm Canyon on the desert side of the Peninsular Mountains, to Marron Valley, Cottonwood, and Deerhorn Flat areas on the coastal side. (Stebbins 2003)

Full Species Range Map
Elevational Range
From sea level to around 7,000 ft. (2,100 m) but usually below 5,000 ft. in San Diego County. (Lemm 2006)

Habitat
Inhabits rocky places with sufficient plants and trees for cover in desert and semi-arid areas. Especially fond of riparian areas.Sometimes found on buildings and other human constructions.

Notes on Taxonomy
Formerly known as: Urosaurus microscutatus - Small-scaled Lizard until synonymized with U. nigricaudus in 1999.
The Common Name was then changed from Black-tailed Brush Lizard to Baja California Brush Lizard.


Alternate and Previous Names (Synonyms)

Urosaurus nigricaudus
- Black-tailed Brush Lizard (Stebbins 2003, Stebbins & McGinnis 2012)
Urosaurus microscutatus - Small-scaled Lizard (Stebbins 1966, 1985)
Uta microscutata - Small-scaled Lizard (Stebbins 1954
Urosaurus microscutatus - Small-scaled Uta (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 Urosaurus Tree and Brush Lizards Hallowell, 1854
Species

nigricaudus Baja California Brush Lizard (Cope, 1864)
Original Description
Urosaurus - Hallowell, 1854 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 7, p. 92
Urosaurus microscutatus - (Van Denburgh, 1894) - Proc. California Acad. Sci., Ser. 2, Vol. 4, p. 298

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

Meaning of the Scientific Name
Urosaurus - Greek - oura - tail and saurus - lizard
nigricaudus
- Latin - black tail

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

Related or Similar California Lizards
U. graciosus - Long-tailed Brush Lizard

U. o. symmetricus - Colorado River Tree Lizard

Uta stansburiana - Side-blotched 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.

Grismer, L. Lee. Amphibians and Reptiles of Baja California, Including Its Pacific Islands and the Islands in the Sea of Cortés. The University of California Press, 2002.

McPeak, Ron H. Amphibians and Reptiles of Baja California. Sea Challengers, 2000.

Lemm, Jeffrey. Field Guide to Amphibians and Reptiles of the San Diego Region (California Natural History Guides). University of California Press, 2006.

Conservation Status

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


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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