Horned lizards are a genus of lizards which are the type genus of the family Phrynosomatidae.
The horned lizard is popularly called a "horned toad", "horny toad" or "horned frog", yet
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.
The spines on its back and sides are made from modified scales, whereas the horns on
the heads are true horns.
Of 15 species of horned lizards in North America, eight are native to the United States.
The largest-bodied and most widely distributed of the US species is the Texas horned lizard.
Description Horned lizards are morphologically similar
to the Australian thorny devil, but are only distantly related.
They also have other similarities, such as being sit-and-wait predators and preying upon
ants, 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 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 bodies to cause them to appear more horned and larger,
so that they are 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 five feet.
They do this by restricting the blood flow leaving the head, thereby increasing blood
pressure and rupturing tiny vessels around the eyelids.
This not only confuses predators, but also the blood tastes foul to canine and feline
predators.
It appears to have no effect against predatory birds.
To avoid being picked up by the head or neck, a horned lizard ducks or elevates its head
and orients its 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 the predator cannot easily get its lower jaw underneath.
Species and subspecies
Giant horned lizard, Phrynosoma asio Cope, 1864
Short-tailed horned lizard, Phrynosoma braconnieri Duméril, 1870
Cedros Island horned lizard, Phrynosoma cerroense Stejneger, 1893
Texas horned lizard, Phrynosoma cornutum Coast horned lizard, Phrynosoma coronatum
Cape horned lizard, P. c. coronatum San Diego horned lizard, P. c. blainvillii
Gray, 1839 California horned lizard, P. c. frontale Van
Denburgh, 1894 Central peninsular horned lizard, P. c. jamesi
Schmidt, 1922 Northern peninsular horned lizard, P. c. schmidti
Barbour, 1921
Ditmars' horned lizard or rock horned lizard, Phrynosoma ditmarsi Stejneger, 1906
Pigmy short-horned lizard, Phrynosoma douglassii
P. d. brachycercum H.M. Smith, 1942 P. d. douglasii
Greater short-horned lizard, Phrynosoma hernandesi Girard, 1858
Flat-tail horned lizard, Phrynosoma mcallii Roundtail horned lizard, Phrynosoma modestum
Girard, 1852
Mexican Plateau horned lizard or Chihuahua Desert horned lizard, Phrynosoma orbiculare
P. o. boucardii P. o. bradti Horowitz, 1955
P. o. orbiculare P. o. orientale Horowitz, 1955
P. o. cortezii P. o. dugesii
Desert horned lizard, Phrynosoma platyrhinos
Southern desert horned lizard, P. p. calidiarum Cope, 1896
Northern desert horned lizard, P. p. platyrhinos Girard, 1852
Sonoran horned lizard, P. p. goodei Stejneger, 1893
Regal horned lizard, Phrynosoma solare Gray, 1845
Mexican horned lizard, Phrynosoma taurus Dugès, 1873
Gulf Coast horned lizard, Phrynosoma wigginsi Montanucci, 2004
Symbol The genus of horned lizards is the official
state reptile of Wyoming.
Texas designated the Texas horned lizard, the official state reptile in 1993 and the
"horned frog" is the mascot of Texas Christian University in Fort Worth, Texas.
TCU is the only known athletic team with the "Horned Frog" as a mascot.
Notes
External links HornedLizards Yahoo Group: Horned Lizard Preservation
and Discussion Horned lizard skulls and info at Digimorph.org
Horned Lizard Conservation Society Phrynosoma.Org: HL Species, Husbandry, and
Conservation Info Phrynosoma.Org: Forum
Zipcodezoo.com Horned Lizards at UTexas.edu
Argentine ants linked to declines in coastal horned lizards
Texas Christian University mascot: What's a Horned Frog?
Horned Toads - Field study of Short-horned Lizards by students of Waterville Elementary
School