Horned lizard
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{{Taxobox
| name = Horned Lizards
| image = Short Horned Lizard.jpg
| image_caption = [[Short-horned Lizard]]
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Reptile|Sauropsida]]
| ordo = [[Squamata]]
| familia = [[Phrynosomatidae]]
| genus = '''''Phrynosoma'''''
| genus_authority = [[Arend Friedrich August Wiegmann|Wiegmann]], 1828
| subdivision_ranks = Species
| subdivision =
See text.
}}
'''Horned lizards''' (''Phrynosoma'') are a genus of the [[Phrynosomatidae]] family of [[lizard]]s. The horned lizard is popularly called a "horned toad," "horny toad", or "horned frog," but it is neither a [[toad]] nor a [[frog]]. The popular names come from the lizard's rounded body and blunt snout, which make it resemble a toad or frog. (''Phrynosoma'' literally means "toad-bodied.") The spines on its back and sides are made from modified scales, whereas the horns on the heads are true horns (i.e. they have a ''horny'' core). There are 14 species of horned lizards in [[North America]], 8 of which are native to the [[United States]]. The largest-bodied and most widely distributed of the U.S. species is the [[Texas horned lizard]] (''P. cornutum'').
== Description ==
Horned lizards are morphologically similar to the [[Australia]]n [[thorny devil]] (''{{}}Moloch horridus''), but are only distantly related. They also have other unique similarities, such as being sit-and-wait predators and preying upon [[ant]]s, and so the two species are considered a great example of [[convergent evolution]].
=== Protection against predation ===
Horned lizards use a wide variety of means to avoid [[predation]]. Their coloration generally serves as [[camouflage]]. When threatened, their first defense is to remain still and hope to avoid detection. If approached too closely, they generally run in short bursts and stop abruptly to confuse the predator's visual acuity. If this fails, they puff up their body to cause it to look more horny, making it appear larger and more difficult to swallow. At least four species are also able to squirt an aimed stream of [[blood]] from the corners of the eyes for a distance of up to 3 feet. They do this by restricting the blood flow leaving the head, thereby increasing blood pressure and rupturing tiny vessels around the [[eyelid]]s. This not only confuses predators, but also the blood tastes foul to [[canine]] and [[feline]] predators. It appears to have no effect against predatory [[bird]]s. To avoid being picked up by the head or neck, horned lizards duck or elevate their head and orient their cranial horns straight up, or back. If a predator tries to take it by the body, the lizard drives that side of its body down into the ground so that the predator cannot easily get its lower jaw underneath the lizard.
=== Diet and decline ===
The diet of most horned lizards species varies from 60-90% [[Red harvester ant|harvester ant]] of the genus ''[[Pogonomyrmex]]'', though they are opportunistic and supplement these with [[termite]]s, [[beetle]]s, [[grasshopper]]s and other small [[insect]]s.
In [[California]], [[Texas]], and other states, horned lizards are considered threatened and given state protection, though none are on the federal endangered species list. The [[Texas horned lizard]] has declined in about 30% of its range, though there is some indication it may be making a comeback. Some California species are also in decline. The decline is usually blamed on development/destruction of habitat, the spread of non-native [[South America]]n ants which compete and war with the harvester ant, and the overuse of [[pesticide]]s which kill harvester ants. In California, the introduced species is the [[Argentine ant]]. In Texas, it is the Argentine ant and the [[Brazil]]ian [[fire ant]]. Both species are highly aggressive and fiercely territorial, and prey on harvester ant queens, destroying the horned lizard's principal source of food.
== In culture ==
Some [[Native Americans in the United States|Native American]] peoples regarded horned lizards as sacred. The animal is a common motif in the art of many [[Native Americans in the United States|Native Americans]] in the Southwestern U.S. (namely, [[Navajo people|Navajo]]) and in [[Mexico]]. In the [[Clint Eastwood]] film ''[[The Outlaw Josey Wales]]'', the character played by [[Chief Dan George]] decides to go to [[Mexico]] based on signs given him by a horned toad.
The horned lizard is the state [[reptile]] of both [[Texas]] and [[Wyoming]], and as the "horned frog," is the mascot of [[Texas Christian University]] (TCU).
The horned toad is also the mascot of [[Coalinga High School]] in [[Coalinga, California]]. The town also holds an annual "Horned Toad Derby".
== Species ==
* [[Giant Horned Lizard]], ''[[Phrynosoma asio]]'' ([[Edward Drinker Cope|Cope]], [[1864]])
* [[Short-tailed Horned Lizard]], ''[[Phrynosoma braconnieri]]'' ([[Auguste Duméril|Duméril]], [[1870]])
* [[Cedros Island Horned Lizard]], ''[[Phrynosoma cerroense]]'' ([[Leonhard Hess Stejneger|Stejneger]], [[1893]])
* [[Texas Horned Lizard]], ''[[Phrynosoma cornutum]]'' ([[Richard Harlan|Harlan]], [[1825]])
* [[Coast Horned Lizard]], ''[[Phrynosoma coronatum]]''
:* [[Cape Horned Lizard]], ''[[Phrynosoma coronatum coronatum]]'' ([[Henri Marie Ducrotay de Blainville|Blainville]], [[1835]])
:* [[San Diego Horned Lizard]], ''[[Phrynosoma coronatum blainvillii]]'' ([[John Edward Gray|Gray]], [[1839]])
:* [[California Horned Lizard]], ''[[Phrynosoma coronatum frontale]]'' ([[J. Van Denburgh|Van Denburgh]], [[1894]])
:* [[Central Peninsular Horned Lizard]], ''[[Phrynosoma coronatum jamesi]]'' ([[Karl Patterson Schmidt|Schmidt]], [[1922]])
:* [[Northern Peninsular Horned Lizard]], ''[[Phrynosoma coronatum schmidti]]'' ([[Thomas Barbour|Barbour]], [[1921]])
* [[Rock Horned Lizard]], ''[[Phrynosoma ditmarsi]]'' ([[Leonhard Hess Stejneger|Stejneger]], [[1906]])
* [[Short-horned Lizard]], ''[[Phrynosoma douglassii]]''
:* ''[[Phrynosoma douglassi brachycercum]]'' ([[Hobart M. Smith|Smith]], [[1942]])
:* ''[[Phrynosoma douglasii douglasii]]'' ([[T. Bell|Bell]], [[1828]])
* [[Mountain Short-horned Lizard]], ''[[Phrynosoma hernandesi]]'' ([[Charles Frédéric Girard|Girard]], [[1858]])
* [[Flat-tail Horned Lizard]], ''[[Phrynosoma mcallii]]'' ([[Edward Hallowell (herpetologist)|Hallowell]], [[1852]])
* [[Roundtail Horned Lizard]], ''[[Phrynosoma modestum]]'' ([[Charles F. Girard|Girard]], [[1852]])
[[Image:Horned_lizards.jpg|240px|thumb|Comparison of ''P. modestum'' and ''P. platyrhinos'']]
* [[Mexican Plateau Horned Lizard]], ''[[Phrynosoma orbiculare]]''
:* ''[[Phrynosoma orbiculare boucardii]]'' ([[Auguste Duméril|Duméril]] & [[Marie Firmin Bocourt|Bocourt]], [[1870]])
:* ''[[Phrynosoma orbiculare bradti]]'' (Horowitz, [[1955]])
:* ''[[Phrynosoma orbiculare orbiculare]]'' ([[Carolus Linnaeus|Linnaeus]], [[1789]])
:* ''[[Phrynosoma orbiculare orinetale]]'' (Horowitz, [[1955]])
:* ''[[Phrynosoma orbiculare cortezii]]'' ([[Auguste Duméril|Duméril]] & [[Marie Firmin Bocourt|Bocourt]], [[1870]])
:* ''[[Phrynosoma orbiculare dugesii]]'' ([[Auguste Duméril|Duméril]] & [[Marie Firmin Bocourt|Bocourt]], [[1870]])
* [[Desert Horned Lizard]], ''[[Phrynosoma platyrhinos]]''
:* [[Southern Desert Horned Lizard]], ''[[Phrynosoma platyrhinos calidiarum]]'' ([[Edward Drinker Cope|Cope]], [[1896]])
:* [[Northern Desert Horned Lizard]], ''[[Phrynosoma platyrhinos platyrhinos]]'' ([[Charles Frédéric Girard|Girard]], [[1852]])
:* [[Sonoran Horned Lizard]], ''[[Phrynosoma platyrhinos goodei]]'' ([[Leonhard Hess Stejneger|Stejneger]], [[1893]])
* [[Regal Horned Lizard]], ''[[Phrynosoma solare]]'' ([[John Edward Gray|Gray]], [[1845]])
* [[Mexican Horned Lizard]], ''[[Phrynosoma taurus]]'' ([[Alfredo Dugés|Dugés]], [[1873]])
* [[Gulf Coast Horned Lizard]], ''[[Phrynosoma wigginsi]]'' ([[R.R. Montanucci|Montanucci]], [[2004]])
== External links ==
* [http://www.digimorph.org/resources/horned.phtml Horned lizard skulls and info at Digimorph.org]
* [http://www.hornedlizards.org/ Horned Lizard Conservation Society]
* [http://www.phrynosoma.org/ Phrynosoma.Org: HL Species, Husbandry, and Conservation Info]
* [http://uts.cc.utexas.edu/~varanus/phryno.html Horned Lizards]
* [http://ucsdnews.ucsd.edu/newsrel/science/mclizard.htm Argentine ants linked to declines in coastal horned lizards]
* [http://www.admissions.tcu.edu/funstuff/horned_frog.asp Texas Christian University mascot: What's a Horned Frog?]
* [http://depts.washington.edu/natmap/projects/waterville/ Horny Toads - Field study of Short-horned Lizards by students of Waterville Elementary School]
[[Category:Phrynosomatids]]
[[Category:Endangered species]]
[[Category:Symbols of Wyoming]]
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