The Texas Horned Lizard


Name: Texas Horned Lizard
Scientific name: Phrynosoma cornutum
Range: Texas, Oklahoma, Kansas, New Mexico, Colorado, parts of Arizona and Mexico. 
Range Map (University of New Mexico)
Habitat: Loose sand or soil
Status: Threatened in Texas and Oklahoma
Diet in the wild: Harvester Ants, isopods, beetles and grubs.
Diet in the zoo: Not yet known
Location in the zoo: "Texas Wild" at the Fort Worth Zoo
Physical description: 
  • Body length up to 2.5 - 4 inches; overall length up to 7 inches. 
  • Variety of colors from light brown, tan or gray, with a short pointed nose and a broad, flattened body. 
  • Tail is short. 
  • specific markings are dark brown spots or yellow and white markings behind the head. 
  • White mid-dorsal stripe
  • There are noticeable spines (modified epidermal scales)  on the back of the head, on the center of the head as horns, on each side of the throat, and rows of spines on each side of the body. 

General information:

The Texas Horned Lizard spends most of their heating up their bodies from the sun, eating harvester ants and chasing away predators.  They dig burrows or occupy one constructed by another animals, often near the mounds of their favorite food source.  They are most active during the warm days of summer and early fall, then hibernate around September or October until April or May and then mating begins right after hibernation.  Metabolism is lowered during the period of hibernation.  After the female and male mate, they build a tunnel underneath the ground to lay up to 13 to 45 eggs.  After that, the female sits on the eggs for one night and then leaves the eggs and never comes back to the nest.  The eggs lie there five to nine weeks long, then the babies hatch their way out of the eggs.  Age of sexual maturity is uncertain, but occurs by three years of age. 

Special anatomical, physiological
or behavioral adaptations:

Texas Horned Lizards have very unusual defense mechanisms. The first defense mechanism they have is when they feel danger, they will flatten out their bodies and just freeze wherever they are at.  They also have the ability to lighten or darken the body to camouflage themselves against the ground, or bury themselves under loose soil.  Burrowing is also an important means of regulating their body temperature. 

Texas horned lizards collect water by "rain harvesting."  They raise and flatten their bodies, then lower the head to collect water flowing along channels formed by their scales. 

When they really threatened their bodies can puff out to make it very difficult for predators to swallow.  They also have ducts near their eyes, through which they can squirt blood a good distance at predators.  If it is sufficiently agitated it may release up to 1/3 of the blood in its body!  Only some of the horned lizard species can expel blood from the eyes. 


The major predators of horned lizards are raptors.  Historically, they have also been attractive to collectors for the pet trade, but they cannot now be legally collected without a permit.  Their  habit of basking on roads puts them at considerable risk, but their greatest vulnerability is to habitat loss.  The spread of fire ants has also driven out their preferred food -- harvester ants.  Unfortunately the lizards are also sensitive to the pesticides used to kill the fire ants. 

Personal Observations:

The Texas Horned Lizard is the State Reptile of Texas.  Temperature permitting, live horned lizards may sometimes be seen in the Mountains and Deserts section of the Texas Wild! exhibit.   

Source Materials and Related Links:

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Natalie Davidson

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