The short-horned lizard (Phrynosoma hernandesi) is native to the U.S. Mountain West and Southwest regions. Internationally, the short-horned lizard's range extends into northern Mexico, Central America and southern Canada. These horned lizards have short spines on top of their heads and grow up to 6 inches when mature. When threatened, some short-horned lizards squirt blood from the corner of their eyes to confuse predators. Their blood contains toxins.
Texas is the primary dwelling place for the Texas horned lizard (Phrynosoma cornutum). In spite of their name, Texas horned lizards may also be found in Texas' neighboring states, including Kansas, Oklahoma and New Mexico. These reptiles have spines all over their bodies, but its two largest spines are on the top of its head. Texas horned lizards are also the only Phrynosoma species with dark brown lines running between their heads and eyes.
The largest horned lizard species in the world is the giant horned lizard (Phrynosoma asio). When fully grown, these lizards can be 10 inches long, including the tail. This reptile is also one of the most slender horned lizards. Giant horned lizards are endemic to western Mexico's Pacific Coast.
Flat-tailed horned lizards (Phrynosoma mcallii) are native to deserts in Southern California, southern Arizona and northern Mexico. These lizards live in desert scrubs and at elevations under 800 feet. As their names suggest, flat-tailed horned lizards have flat tails and bodies; these lizards have oval-shaped bodies. As adults, flat-tailed horned lizards reach lengths of 3.25 inches. The flat-tailed species are the only horned lizards with a dark brown stripe on their backs.
Also known as Phrynosoma platyrhinos, desert horned lizards have long, thin horns instead of horns with a wide base. Counting their tails, desert horned lizards grow up to 5.5 inches. The distribution range of desert horned lizards includes Idaho, Utah, Oregon, Nevada and Arizona. Desert horned lizards also have flatter bodies than other horned lizard species, but not as flat as the flat-tailed horned lizard.
A regal horned lizard receives its name from the crown of flat spines emerging from the back of its head, which consists of four pairs of horns. Regal horned lizards live at elevations of over 4,500 feet. This lizard's native range covers southern Arizona, northern Mexico and southwestern New Mexico. Regal horned lizards burrow into the ground to keep warm during the winter.