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A Guide to the Amphibians
and Reptiles of California


Blainville's Horned Lizard - Phrynosoma blainvillii

Gray, 1839

(= Coast Horned Lizard) (= Anota coronatum)
Click on a picture for a larger view



Coast Horned Lizard Range Map
Range in California: Red



observation link



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Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult male, 3,000 ft., San Gabriel Mountains, Los Angeles County Note enlarged femoral pores
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult female, 3,000 ft., San Diego County,
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult male, Alameda County
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
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
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
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
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
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
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult, San Benito County
© Jackson Shedd
Adult, San Benito County
© Jackson Shedd
Adult, Butte County
© Jackson Shedd
Adult, Butte County
© Jackson Shedd
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult, San Luis Obispo County
© Rodney Starr
Adult, Vandenburg AFB, Santa Barbara County
© Phil Vogel
Adult, Santa Barbara County
© John Sullivan
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult, Monterey County
© John Sullivan
Adult, San Benito County
© John Sullivan
Adult, San Benito County
© John Sullivan
Adult, Kings County © Patrick Briggs
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Adult, Diablo Range, Santa Clara County © Jon Hirt 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
Coast Horned Lizard Coast Horned Lizard Great Basin Collared Lizard ant sign
Adult, Kern Plateau, Kern County
© Brad Alexander
Adult, Alameda County Blainville's Horned Lizards are covered with small granular scales interspersed with larger pointed scales.

Harvester Ants are a primary source
of food for Blainville's Horned Lizards
(and other species of horned lizards.)
   
Blood-squirting Defensive Behavior
Coast Horned Lizard Coast Horned Lizard    
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.
   
Breeding Adults
Coast Horned Lizard horned lizarCoast Horned Lizardsds    
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 
   
     
Juveniles
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Juvenile, San Diego County Juvenile, San Diego County
Coast Horned Lizard juvenile Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
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 
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard
Juvenile, San Gabriel Mountains, Los Angeles County Juvenile male, San Diego County
Coast Horned Lizard Coast Horned Lizard    
Juvenile, Monterey County
© John Sullivan
Juvenile, Contra Costa County
© Ricky Ortiz
   
       
Comparison of Blainville's Horned Lizard with Desert Horned Lizard  (based on Stebbins, 2003)
Coast Horned Lizard fringe Coast Horned Lizard fringe Coast Horned Lizard fringe  
Blainville's Horned Lizards have 2 rows of pointed fringe scales on the lower part of each side of the body.
 
Southern Desert Horned Lizard Southern Desert Horned Lizard Southern Desert Horned Lizard  
Desert Horned Lizards have only 1 row of fringe scales on each side of the body  
Coast Horned Lizard fringe Coast Horned Lizard fringe Coast Horned Lizard fringe  
Blainsville's Horned Lizards have 2 or 3 rows of enlarged pointed scales on each side of the throat.  
Coast Horned Lizard fringe Coast Horned Lizard fringe Coast Horned Lizard fringe  
Desert Horned Lizards have only 1 row of slightly enlarged scales on each side of the throat.  
       
Habitat
Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard 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, Los Angeles County
© Todd Battey
Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat
Habitat, San Gabriel Mountains, Los Angeles County Habitat, Butte County.

Coastal sand dunes habitat,
San Luis Obispo county
Coastal Sage habitat,
San Diego County
Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat
Habitat, Alameda County

Habitat, Contra Costa County Habitat, Kings County
© Patrick Briggs
Habitat, San Gabriel Mountains,
Los Angeles County
Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat Coast Horned Lizard Habitat
Adult in habitat, San Luis Obispo County Habitat, Alameda County Habitat, San Diego County Habitat, Vandenburg AFB,
Santa Barbara County © Phil Vogel
Coast Horned Lizard Habitat california kingsnake habitat Coast Horned Lizard Habitat Coast Horned Lizard
Habitat, Carrizo Plain,
San Luis Obispo County

San Diego County coastal sage habitat Habitat, Alameda County Adult in habitat, Diablo Range, Santa Clara County © Jon Hirt
Short Videos
Coast Horned Lizard Coast Horned Lizard Coast Horned Lizard  
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. Caitanya tells us about a horned lizard she found then lets it go.
© Robert de Vico
 
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.

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.

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)
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
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.
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 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

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
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.

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 and the Endangered and Threatened Animals List which are 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


 

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