Greater Short Horned Lizard

Greater Short Horned Lizard

NPS

Characteristics
Greater Short-horned Lizards (Phrynosoma hernandesi) are exceptionally flat and wide bodied with lots of short horns and because of this appearance have often been called “Horned Toads” but they are in no way toads as they are distinctly reptiles and not amphibians.

They grow up to about 5 inches long as measured from snout to vent. Short, stubby horn-like scales project from the back of the head with a wide gap separating the bases of the two central horns. Several pointed scales project from the back. An exceptionally noticeable line of large horned scales fringes the side of the body between the short legs.

Base coloration can be tan, yellow-brown, orange-brown, reddish-brown or gray and usually matches the soil where the individual lives remarkably well. There are two large dark blotches on the neck and a series of dark blotches down the back. The chin is often mottled gray and the belly may have some yellow-orange or reddish orange but is much paler than the back. The scales on the belly are smooth. The females tend to grow a little bigger than the males. This species was named for Francisco Hernandez Medico, a Spanish explorer who wrote a description of it in 1651.

Food Sources
Ants provide the bulk of this lizard’s food, but it also eats beetles, grasshoppers, spiders, young snakes, snails, sowbugs and a variety of other insects and invertebrates. Often they will wait for their prey to come by and snap up the unsuspecting prey whole. They rely heavily on their camouflage to avoid their many predators which include hawks, owls, roadrunners, snakes, lizards, wolves and coyotes. If spotted by a predator they can inflate their bodies up to twice their normal size and with the horns protruding appear to be a very unappetizing meal.

They can also build up the blood pressure in regions behind their eyes and accurately squirt blood up to three feet from ducts in the corner of their eyes at attacking predators. This deters many would be predators from continuing their attack. The blood also contains a chemical that is noxious to wolves and coyotes. They may also roll onto their backs and play dead and again escape becoming prey.

Habitat and Territory
The Greater Short-horned Lizard can be found in a variety of habitats including semiarid plains, shortgrass prairies, sagebrush deserts, shrubby plateaus, juniper, pine or fir forests, and up into the mountains, such as the Pryor Mountains.

They are more tolerant of cooler temperatures than most other reptiles, often emerging from hibernation in April and returning to their dens in October. They range from most of Montana, Wyoming and Colorado except for the highest elevations above 10,000 feet or so and extend down through much of Utah, Arizona and New Mexico.

Early Risers
Mating takes place in spring and the young are born two to three months later. Litter size is usually 6 to 18, but up to 48 has been recorded. The young are born in a clear amniotic sac from which they must break free. They do not have horns when they are born, but are able to take care of themselves and are able to get around when a day old. The males can become sexually active at age one whereas the females usually take two years before they are sexually active.

Most of those that review the differences between reptiles and amphibians after seeing a Greater Short-horned Lizard never call them a toad again –we hope.