A Guide to the Amphibians
and Reptiles of California

Blainville's Horned Lizard - Phrynosoma blainvillii

Gray, 1839

(= Coast Horned Lizard) (= Anota coronatum)

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

Red: Historic Range in California

Click on the map for a topographical view

Map with California County Names

Adult female, San Diego County,

Adult male, Alameda County

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

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

Enlarged femoral pores

Adult male, Alameda County

Adult male, from coastal dunes, San Luis Obispo county, partially buried in loose sand on the right.
(The two SLO dunes lizards shown here both have nice bright white side fringe and markings on the back.)

Adult from coastal dunes, San Luis Obispo County © Jay Smart

Adult, Santa Ana Mountains,
Riverside County © Ken Pitts

Adult Female, Contra Costa County
© Sam Murray

Adult Male, Contra Costa County
© Sam Murray

Adult, Los Angeles County
© Todd Battey

Adult, Santa Clara County © Jon Hirt

Adult, Kings County © Patrick Briggs

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, Butte County
© Jackson Shedd

Adult, San Luis Obispo County
© Rodney Starr

Adult, Vandenburg AFB, Santa Barbara County
© Phil Vogel

Adult, Santa Barbara County
© John Sullivan

Adult, Monterey County
© John Sullivan

Adult, San Benito County
© John Sullivan

Adult, Kings County © Patrick Briggs

Adult, Diablo Range, Santa Clara County © Jon Hirt

Adult, Monterey County
© Benjamin German

Adult, Kern Plateau, Kern County
© Brad Alexander

Adult, Ventura County © Tony Charlton

Adult, Contra Costa County
© Zachary Lim

Adult, Alameda County © Marcia Grefsrud/CDFW

Adult, Riverside County
© Huck Triggs

Adult, San Diego County
© Paul Maier

Large adult, Orange County © Dave Beller

Adult, Santa Barbara County
© Francesca Heras

Adult, Morro Bay, San Luis Obispo County © Joel A. Germond

Adult in habitat, Santa Monica Mountains, Ventura County
© Grigory Heaton

Adult, Contra Costa County
© Ben DeDominic

Adult, Contra Costa County
© France

Califa and Caitanya de Vico (aka Gypsettwins) show off some of the horned lizards they saw on a fun spring hike in the Los Angeles County hills.
© Robert de Vico

Adult, San Benito County
© Zchary Cava

Blainville's Horned Lizards are covered with small granular scales interspersed with larger pointed scales.

Juveniles

Juvenile, San Diego County

Juvenile, San Gabriel Mountains, Los Angeles County

Juvenile male, San Diego County

Juvenile, San Benito County
© Andy Stocker

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

Juvenile, San Diego County © Jay Keller

Juvenile, Los Angeles County
© Becky Trask

Juvenile, Monterey County
© John Sullivan

Juvenile, San Diego County
© Tim Valentine

This San Diego County juvenile shows how easily it can blend into the background to avoid detection.
© Tim Valentine

Juvenile, Contra Costa County
© Ricky Ortiz

Juvenile, Ventura County
© Tony Charlton

Juvenile, Orange County
© Tadd Kraft

Juvenile, Santa Barbara County
© Francesca Heras

Juvenile with red coloring, San Diego County © Julie Stout

Blood-squirting Defensive Behavior

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

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.

This Riverside County adult is covered with blood after using its blood deterrant defense behavior, however, in this case the blood was not squirted, it just oozed out of the eyes. © Curtis Croulet

Adults in the Mating Season

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 below) which could be the result of the previous year's breeding. © Becky Trask

A pair of mating adults, Los Angeles County © Huck Triggs
(A short video of them.)

A pair of mating adults, male on top,
San Diego County © Andrew Borcher

Watch a YouTube video of two adult horned lizards in Contra Costa County engaged in what appears to be violent courtship behavior and possibly mating at the end. The female either has a bloody head injury or she has squirted blood from her eye in defense.
© Andre Giraldi

Mating adults, San Luis Obispo County
© Lillian Germond

These two adult horned lizards were found lying motionless. They were probably engaged in some kind of courtship or breeding behavior when they felt threatened and remained motionless to avoid detection. Horn lizards like to rely on their camouflage to stay out of trouble.
© Christine Frei

Predators

An adult Red Diamond Rattlesnake eating an adult Blainville's (Coast) Horned Lizard in San Diego County © Shane Caver

Prey

Horned lizards eat mostly black or red harvester ants such as these.

These pictures show the feces of a Texas Horned lizard:
Intact (left)
Crushed (right) (Notice that it is composed mostly of ants.)

Comparison of Blainville's Horned Lizard with Desert Horned Lizard (based on Stebbins, 2003)

Blainville's Horned Lizards have 2 rows of pointed fringe scales on the lower part of each side of the body.

Desert Horned Lizards have only 1 row of fringe scales on each side of the body

Blainsville's Horned Lizards have 2 or 3 rows of enlarged pointed scales on each side of the throat.

Desert Horned Lizards have only 1 row of slightly enlarged scales on each side of the throat.

Habitat

Habitat, 3,000 ft., San Diego County

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

Chaparral/sandy wash habitat
San Benito County

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 sand dunes habitat,
San Luis Obispo County

Habitat, Alameda County

Habitat, San Diego County

Habitat, Carrizo Plain,
San Luis Obispo County

San Diego County coastal sage habitat

Habitat, Alameda County

Habitat, Santa Ana Mountains,
Riverside County

Short Videos

Two different Blainville's 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 Blainville's horned lizard runs around in San Diego County.

This is a pair of mating Blainville's Horned Lizards in Los Angeles County. It's interesting that they are belly to belly. With all those horns and spines, it's probably safer that way. © Huck Triggs

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.
Males have enlarged postanal scales and a swollen tail base during the breeding season.
Females are larger in size than males.
Each side of the body has two rows of pointed fringe scales. (Stebbins, 2003)
Each side of the throat has two or three rows of enlarged pointed scales. (Stebbins, 2003)

Color and Pattern

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.

Life History and Behavior

Activity

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

Horned lizards roam a home range, which may overlap with others and change seasonally, but male horned lizards do not defend their territory aggressively like other kinds of lizards. They don't have patches of brighly-colored scales to display to other males. Because they don't combat other males during the breeding season, their bodies are smaller than the bodies of female horned lizards, which lets them use their energy in searching for females instead of maintaining a large body size.
(Sherbrooke, 2003)

Longevity

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

Defense

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.

Diet and Feeding

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

Reproduction

Lays 6 - 21 eggs (averaging around 12) from May to June.
Eggs hatch from August to September.
Some females may lay two clutches of eggs in a year.

Habitat

Inhabits open areas of sandy soil and low vegetation in valleys, foothills and semiarid mountains. 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. Often found near ant hills feeding on ants.

Geographical Range

Historically found in California 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 now been severely fragmented due to land alteration.

Some sources still mention the range extending to Grasshopper Flats in Siskiyou County, but this was listed as dubious in Rober Stebbins' 1985 field guide, and dropped from his 2003 field guide. The record farthest north at Kennett is from a location that was flooded with the construction of Shasta Dam and Shasta Reservoir.

Elevational Range

Found at elevations from sea level to 8,000 ft. (2,438 m).

Notes on Taxonomy

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

Alternate and Previous Names (Synonyms)

Commonly called: "Horny Toad," "Horned Toad," "Horned Frog."

Phrynosoma coronatum - Coast Horned Lizard (Stebbins 1954, 1966, 1985, 2003)
Phrynosoma coronatum blainvillii - San Diego Horned Lizard (Smith 1946)
Phrynosoma coronatum frontale - Californian Horned Lizard (Smith 1946)
Phrynosoma blainvillii blainvillii - Blainville Horned-toad (Agama coronatum; Phrynosoma coronatum, part; Phrynosoma modestum. Pacific Horned Lizard; Blainville's Horned Lizard, part; California Horned Lizard, part; Pacific Horned Toad; Crowned Horned Lizard, part; Little Horned Lizard) (Grinnell and Camp 1917)
Phrynosoma blainvillii frontale - California Horned Toad (Phryosoma frontalis; Phrynosoma blainvillii, part; Phrynosoma coronatum, part; Phrynosoma cornutum; Batrachosoma coronatum; Tapaya coronata. California Horned Lizard, part; Crowned Horned Lizard, part.) (Grinnell and Camp 1917)

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	Fitzinger, 1843
Genus	Phrynosoma	Horned Lizards	Wiegmann, 1828
Species	blainvillii	Blainville's Horned Lizard	Gray, 1839
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 Eponyms Henri Marie Ducrotay de Blainville (1777-1850) a French zoologist and anatomist, first described the species Phrynosoma coronatum - Coast Horned Lizard - in 1835. In 1839 Gray described the subspecies Phrynosoma coronatum blainsvillii. Gray used the subspecific name "*blainsvillii" and the common name "Blainsville's* Horned Lizard" to honor H. M. Blainville. See: Biographies of Persons Honored in the Herpetological Nomenclature © 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
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
California Department of Fish and Wildlife 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. 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. 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. 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. Listed as coast horned lizard on the Special Animals list.
Organization	Status Listing	Notes
NatureServe Global Ranking	G4	Apparently Secure
NatureServe State Ranking	S4	Apparently Secure
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Wildlife	SSC	Species of Special Concern
Bureau of Land Management	S	Sensitive
USDA Forest Service	None
IUCN	LC	Least Concern

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