The Texas Horned Lizard
||Name: Texas Horned Lizard|
|Scientific name: Phrynosoma cornutum|
|Range: Texas, Oklahoma, Kansas, New Mexico, Colorado, parts of Arizona
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|
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.
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.
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WhoZoo Animal Index
Reptiles and Amphibians at the Fort Worth Zoo