The San Diego horned lizard or Blainville's horned lizard (''Phrynosoma blainvillii'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

of phrynosomatid

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia altho ...

native to southern and central

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

and northern

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

Taxonomy

Described as a distinct species by

John Edward Gray John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used f ...

in 1839 (being named after

Henri Marie Ducrotay de Blainville Henri Marie Ducrotay de Blainville (; 12 September 1777 – 1 May 1850) was a French zoologist and anatomist. Life Blainville was born at Arques, near Dieppe. As a young man he went to Paris to study art, but ultimately devoted himself to natur ...

), it was later reclassified as a subspecies of the

coast horned lizard The coast horned lizard (''Phrynosoma coronatum'') is a species of phrynosomatid lizard endemic to Baja California Sur in Mexico. As a defense the lizard can shoot high pressure streams of blood out of its eyes if threatened. Taxonomy It was ...

(''P. coronatum'') in 1933. However, studies by Adam Leaché in 2006 and 2009 found sufficient genetic evidence to again classify ''P. blainvillii'' as a distinct species. In 2021,

Gunther Köhler Gunther Köhler (born 20 May 1965 in Hanau) is a German herpetologist. His research is primarily focused in Central America and in the West Indies. Career In 1995, Köhler received a doctorate in natural sciences at the Goethe University Frankfurt ...

again reclassified ''blainvillii'' as a subspecies of ''P. coronatum'', although the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...

has not followed this.

Appearance

The San Diego Horned Lizard or the Blainville's Horned Lizard (Phrynosoma blainvillii) is a flat bodied lizard with long spiky horns located on the top and side of its head and has smaller spikes throughout its body and tail. The length of an adult size lizard can range from 2.5 inches to 4.5 inches measure from the tip of its snout to its bottom just before where the tail starts. They are either red, brown, yellow or gray in color and have several black spots on their back and neck.

Distribution

This species ranges from the Central Valley of

south through

southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban ...

to northern

Habitat and range

They range from

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primar ...

Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Gov ...

, and

Shasta Reservoir Shasta Lake, also popularly known as Lake Shasta, is a reservoir in Shasta County, California, United States. It began to store water in 1944 due to the impounding of the Sacramento River by Shasta Dam, the ninth tallest dam in the United State ...

. These lizards are usually found to habitat near mountains in areas that are sandy, with low vegetation and near ant hills.

Defense

Their first defensive strategy to avoid predators is to use their body color to blend in with their surroundings and to remain still.https://scholarworks.calstate.edu/downloads/mk61rm52t If they are seen they will try to run away and hide in bushes to cover themselves in sand. If they can not hide from predators they will try other defensive tactics such as hissing, biting, or using the horns on their heads and body as weapons. If they are out of defensive options they can shoot blood out of their eyes to scare off predators.

Diet

Their diet is mostly Harvester ants but they do eat spiders, beetles, termites, and other insects.

Reproduction

In Southern California, the San Diego horned lizard's reproductive period ranges from early March to June. Each year the female Blainville's horned lizard can lay about 6-21 eggs in a year. A few months after they are laid in August-September they begin to hatch. The females will lay their eggs in the

Santa Monica Santa Monica (; Spanish: ''Santa Mónica'') is a city in Los Angeles County, situated along Santa Monica Bay on California's South Coast. Santa Monica's 2020 U.S. Census population was 93,076. Santa Monica is a popular resort town, owing to i ...

and

Simi Hills The Simi Hills are a low rocky mountain range of the Transverse Ranges in eastern Ventura County and western Los Angeles County, of southern California, United States. Geography The Simi Hills are aligned east-west and run for , and average aro ...

area.

Gender

The difference between males and females is that the female lizards are bigger than the males. The males also have bigger horns on the base of their tails and have noticeable pores on the interior of their hind legs. https://scholarworks.calstate.edu/downloads/mk61rm52t

Population

The San Diego horned lizard is no longer present in many sections of Southern California due to urbanization, and other types of habitat loss. The population of horned lizards are declining because of habitat loss or degradation, hunting or capturing by humans and an increase of invasive species of Argentine ants.https://scholarworks.calstate.edu/downloads/mk61rm52t The lizard’s population was also impacted by the curio trade from 1890-1910, where it was estimated that 115,000 horned lizards in California were killed stuffed and sold as souvenirs.

Predators

These lizards are vulnerable to a wide range of predators such as

Badgers Badgers are short-legged omnivores in the family Mustelidae (which also includes the otters, wolverines, martens, minks, polecats, weasels, and ferrets). Badgers are a polyphyletic rather than a natural taxonomic grouping, being united by the ...

Foxes Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelve sp ...

Coyotes The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...

, house pets,

Greater Roadrunner The greater roadrunner (''Geococcyx californianus'') is a long-legged bird in the cuckoo family, Cuculidae, from the Aridoamerica region in the Southwestern United States and Mexico. The scientific name means "Californian earth-cuckoo". Along w ...

Loggerhead Shrike The loggerhead shrike (''Lanius ludovicianus'') is a passerine bird in the family Laniidae. It is the only member of the shrike family endemic to North America; the related northern shrike (''L. borealis'') occurs north of its range, however it ...

American Kestrel The American kestrel (''Falco sparverius''), also called the sparrow hawk, is the smallest and most common falcon in North America. It has a roughly two-to-one range in size over subspecies and sex, varying in size from about the weight of ...

Burrowing Owl The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or an ...

, and the

Northern Pacific Rattlesnake ''Crotalus oreganus'', commonly known as the (northern) Pacific rattlesnake, Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. . is a venomous pit viper species found in western North A ...

.https://scholarworks.calstate.edu/downloads/mk61rm52t

References

{{Taxonbar, from=Q5314623 Phrynosoma Reptiles of Mexico Reptiles of the United States Fauna of the Southwestern United States Fauna of the Baja California Peninsula Fauna of the California chaparral and woodlands Reptiles described in 1839 Taxa named by John Edward Gray