A Guide to the Amphibians
and Reptiles of California

Phrynosoma blainvillii - Blainville's Horned Lizard
(Coast Horned Lizard)

(=Anota coronatum)

Click on a picture for a larger view

Range in California: Red

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Adult, 3,000 ft., San Gabriel Mountains, Los Angeles County

Adult, Alameda County

Adult, 3,000 ft., San Diego County,

Juvenile, San Gabriel Mountains,
Los Angeles County

Juvenile, San Diego County

Adult, Alameda County

Juvenile, San Diego County

Juvenile, San Benito County
© Andy Stocker

Adult Female, Contra Costa County
© Sam Murray

Adult Male, Contra Costa County
© Sam Murray

Adult, Los Angeles County
© Todd Battey

Adult, Santa Ana Mountains, Riverside County © Ken Pitts

Adult, Butte County
© Jackson Shedd

Juvenile, Contra Costa County
© Ricky Ortiz

Adult, Santa Clara County. © Jon Hirt

Adult, Kern Plateau, Kern County
© Brad Alexander

Adult with a patternless pale ground color that matches the sand on the beach where it was found in San Diego County.
© John Andermann

Adult, San Benito County
© Jackson Shedd

Adult, San Luis Obispo County, hiding, partially buried, in loose sand.

Adult, Santa Cruz Mountains
© Jackson Shedd
This lizard squirted blood from its eyes just before the photographs were made, which explains the reddish coloring on its head.

Adult, from coastal dunes, San Luis Obispo county

Adult, Kings County © Patrick Briggs

Adult, San Luis Obispo County
© Rodney Starr

Adult, Vandenburg AFB, Santa Barbara County
© Phil Vogel

In early April of 2007, Becky Trask sent me these pictures of breeding adult horned lizards found at 5,200 ft. in Los Angeles County. In mid April of 2008 she discovered a juvenile at the same location (shown on the right) which could be the result of the previous year's breeding. © Becky Trask

This injured adult from a backyard in San Luis Obispo County shows blood above one eye. When threatened, horned lizards will often spurt blood from a pore near the eyelid to deter the attacker, in this case, a dog. © Martha Lindl

Newly-hatched juvenile next to U.S. quarter to show how small it is, Contra Costa County. © Jerry L. Boyer

Coast Horned Lizards have two rows of fringe on the lower part of each side of the body. Compare with the Desert Horned Lizard which has one row of fringe on each side.

Texas Horned Lizard Food (similar to Coast horned lizard food.)

Habitat

Habitat, 3,000 ft., San Diego County

Habitat, Riverside County. The bare spot in the foreground is a nest of harvester ants, a primary food source for Coast Horned Lizards.

Chaparral/sandy wash habitat
San Benito County

Habitat, Los Angeles County
© Todd Battey

Habitat, San Gabriel Mountains, Los Angeles County

Habitat, Butte County.

Coastal sand dunes habitat,
San Luis Obispo county

Coastal Sage habitat,
San Diego County

Habitat, Alameda County

Habitat, Contra Costa County

Habitat, San Gabriel Mountains,
Los Angeles County

Adult in habitat, San Luis Obispo County

Habitat, Alameda County

Habitat, San Diego County

Short Videos

Two different horned lizards are shown running quickly for a short distance then stopping to hide by blending in with the background, typical behavior for this type of lizard.

A juvenile horned lizard runs around in San Diego County.

Description

Size

Adults are 2.5 - 4.5 inches long from snout to vent (6.3 - 11.4 cm)

Appearance

A flat-bodied lizard with a wide oval-shaped body, scattered enlarged pointed scales on the upper body and tail, and a large crown of horns or spines on the head. The two center horns are the longest. The sides of the body have two rows of pointed fringe scales. (Compare with the Desert Horned Lizard which only has one row of fringed scales on the sides.)
Color is reddish, brown, yellow, or gray, with dark blotches on the back and large dark spots on the sides of the neck.
The belly is cream, beige, or yellow, usually with dark spots, and the belly scales are smooth.
Males have enlarged postanal scales and a swollen tail base during the breeding season.

Behavior & Natural History

Diurnal. Active during periods of warm weather, retreating underground and becoming inactive during extended periods of low temperatures or extreme heat.

When threatened, this lizard is capable of running away quickly for only a short distance, and usually runs under a low bush. Its main defense is remaining motionless using its cryptic coloring to blend into the background and make it difficult to see. It will crouch down low to prevent shadows that could make it easier to see, sit still to avoid detection, even changing its color slightly to better match the background, and will sometimes shake the body from side to side to partially bury itself in loose soil.

Inflates with air when threatened, making it larger and hard to swallow. Opens its mouth and make hissing noises as a threat display. When threatened and grabbed, it will bite and move the head from side to side to jab with its horns. As a last resort, it will spray the intruder with blood from the corners of its eyes. This blood has been found to repel coyotes and foxes and possibly other predators.

Known to live up to 10 years in captivity, although captive animals normally do not live very long at all due to the difficulties of feeding them a proper diet.

Diet

Eats mainly ants, especially harvester ants, but also consumes other small invertebrates such as spiders, beetles, termites, flies, honeybees, moth larvae, and grasshoppers.

Reproduction

6 - 21 eggs (averaging around 12) are laid May to June, hatching from August to September. Some females may lay two clutches in a year.

Range

Found along the Pacific coast from the Baja California border west of the deserts and the Sierra Nevada, north to the Bay Area, and inland as far north as Shasta Reservoir, and south into Baja California. Ranges up onto the Kern Plateau east of the crest of the Sierra Nevada. The range has been fragmented due to land alteration.

Habitat

Inhabits open areas of sandy soil and low vegetation in valleys, foothills and semiarid mountains from sea level to 8,000 ft. (2,438 m) in elevation. Found in grasslands, coniferous forests, woodlands, and chaparral, with open areas and patches of loose soil. Often found in lowlands along sandy washes with scattered shrubs and along dirt roads, and frequently found near ant hills.

Taxonomic Notes

In a study published in July, 2009*, Leaché et al recognized 5 phylogeographic groups in the Coast Horned Lizard complex, which include 3 ecologically divergent and morphologically diagnosable species: Phrynosoma coronatum, Phrynosoma cerroense, and Phrynosoma blainvillii. They show that Phrynosoma blainvilli, which occurs in California, consists of 3 phylogeographic groups, but conclude that these groups do not represent three distinct species.

From the abstract to the paper:

"...Although the hypothesis that the 3 phylogeographic groups distributed across California each represent distinctive species is not supported by all of the operational species criteria evaluated in this study, the conservation status of the imperiled populations represented by these genealogical units remains critical."

*Leaché, Adam D., Michelle S. Kooa, Carol L. Spencera, Theodore J. Papenfussa, Robert N. Fisherb and Jimmy A. McGuirea. Quantifying ecological, morphological, and genetic variation to delimit species in the coast horned lizard species complex (Phrynosoma). Proceedings of the National Academy of Sciences published online before print July 22, 2009, doi:10.1073/pnas.0906380106.

Leache and McGuire (2006, Molecular Phylog. Evolution 39:628-644) named four subclades of Phrynosoma - 3 in our area: Anota, Doliosaurus, and Tapaja.

Montanucci, 2004, Geographic variation in Phrynosoma coronatum (Lacertilia, Phrynosomatidae): Further evidence for a Peninsular Archipelago. Herpetologica 60(1): 117-139, restricted P.coronatum to southern Baja populations, naming the population which occurs in California Phrynosoma blainvillii.

2 subspecies were recognized in California before 1997:
Phrynosoma coronatum blainvillii - San Diego Horned Lizard
Phrynosoma coronatum frontale - California Horned Lizard

Conservation Issues (Conservation Status)

Threatened and eliminated from many areas due to habitat destruction from human development and agriculture, and the spread of nonnative ants, such as Argentine Ants (ridomyrmex humilis) which displace the native ant food source. Before commercial collecting was banned in 1981, this lizard was extensively exploited by the pet trade and the curio trade. (At the turn of the century, horned lizards were coated with varnish and sold to tourists.)

Taxonomy
Family	Phrynosomatidae	Zebra-tailed, Earless, Fringe-toed, Spiny, Tree, Side-blotched, and Horned Lizards
Genus	Phrynosoma	Horned Lizards
Species	blainvillii	Blainville's Horned Lizard
Original Description
Phrynosoma coronatum - (Blainville, 1835) - Nouv. Ann. Mus. Hist. Nat. Paris, Vol. 4, p. 284, pl. 25, fig. 1 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Phrynosoma - Greek - phrynos - toad and soma - body - refers to the squat, toad-like appearance coronatum - Latin - crowned - ref. joining of two large occipital plates from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
P. coronatum - Coast Horned Lizard P. c. blainvillei - San Diego Horned Lizard P. c. frontale - California Horned Lizard "Horny Toad," "Horned Toad"
Related or Similar California Lizards
Phrynosoma platyrhinos calidiarum - Southern Desert Horned Lizard Phrynosoma platyrhinos platyrhinos - Northern Desert Horned Lizard Phrynosoma mcallii - Flat-tail Horned Lizard Phrynosoma douglasii - Pygmy Short-horned Lizard
More Information and References
Natureserve Explorer California Dept. of Fish and Game SDNHM Horned Lizard Conservation Society 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. Sherbrooke, Wade C. Horned Lizards, Unique Reptiles of Western North America. Southwest Parks and Monuments Association, 1981. Sherbrooke, Wade C. Introduction to Horned Lizards of North America. University of California Press, 2003.

Conservation Status
The following status listings come from the Special Animals List which is published by the California Department of Fish and Wildlife. This species was formerly listed separately by two former subspecies on the Special Animals List, but it is now listed as only one species.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Wildlife	DFG:SSC	California Species of Special Concern
Bureau of Land Management	BLM:S	Sensitive
USDA Forest Service	USFS:S	Sensitive
Natureserve Global Conservation Status Ranks	G4G5S3S4	Apparently Secure
World Conservation Union - IUCN Red List	LC	Least Concern

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Phrynosoma blainvillii - Blainville's Horned Lizard (Coast Horned Lizard)

Phrynosoma blainvillii - Blainville's Horned Lizard
(Coast Horned Lizard)