Greater Short-horned Lizard

Greater Short-horned Lizard

Phrynosoma hernandesi. By Ellen Horowitz

This story is featured in Montana Outdoors September-October 2010 issue

When friends told me they’d seen greater short-horned lizards by the Sun River west of Augusta, I had to check out the spot. I was curious about the prehistoric-looking creatures. Could they really squirt blood from their eyes, as a Texas naturalist once informed me? What’s more, because they are generally lizards of the open plains, most commonly found in southeastern Montana, this sighting just a few miles from Gibson Reservoir meant I didn’t have to drive completely across the state to see one.

The greater short-horned is one of four lizards in Montana. Commonly called a horny toad or horned toad, it technically is not a toad (amphibian) but a lizard (reptile). The confusion is understandable. The greater short-horned lizard has a broad toadlike shape, and its scientific name, Phrynosoma, is Greek for “toad body.”

The lizard has an oval, flattened body, a heart-shaped head (when viewed from above), a single row of light-colored scales along its sides, and small, hornlike projections near the back of its head. The lizards are only 2.5 to 3.5 inches long, with males smaller than females. Even though my friends had

told me almost exactly where to look for the little reptiles, finding one wasn’t easy. Their body color varies widely, from tan-gray to reddish brown to olive green-gray. “They blend in spectacularly with the ground where they live,” says greater short-horned lizard expert Jim Barron, associate professor of biology at Montana State University—Billings. Dark splotches, white spots, and abundant spines and scales enhance the animal’s camouflage.

Habitat and Habits
Of the 13 horned lizard species in North America, the greater short-horned is the most widespread, ranging from southern Alberta to northern Mexico. It occurs east of the Rocky Mountain Front in dry, open habitat. Generally, the bleaker the natural landscape, the more likely you’ll find greater short-horned lizards. In Montana, scientists have found them as high as 6,500 feet in the Pryors, on ridge crests between coulees, in sparse grass, and in sagebrush with sun-baked soil.

The lizards usually mate in early May shortly after emerging from their winter burrows. As the young grow inside her, the female becomes round in shape, “like a racquetball with legs,” says Barron. By the time she gives birth to her ten or so young, anytime between late July and early August, her weight has doubled.

Eat or Be Eaten
A greater short-horned lizard may not look appetizing to us, but it is tasty prey to snakes, raptors, ravens, foxes, coyotes, and other animals. In addition to its cryptic coloration, the lizard stays alive by staying still. That’s also how it hunts. When an unsuspecting insect wanders close enough, the lizard strikes.

The greater short-horned feeds on crickets, beetles, grasshoppers, and ants—especially the western harvester ant.

When spotted by a predator at close range, the lizard often responds by holding open its mouth or performing “pushups” from all four legs—behaviors known as threat postures. It can also inflate its lungs to puff up and enlarge its appearance, which makes a snake think twice about how far it wants to unhinge its jaws to devour dinner.

And what about that ocular blood squirting? Barron tells me that even though it’s true many horned lizard species emit blood from their eyes during extreme stress, Phrynosoma hernandesi is not one of them.

The Future
My husband and I had spent two hours looking for the lizards before he spotted a skittering “rock” that abruptly stopped. He called me over. “Horned toad,” he said. “Look by my left boot.” It took me nearly a minute to locate the motionless form hidden against a backdrop of grayish brown earth and a few strands of prairie grass. The lizard never moved the whole time I watched it, even when I bent down to take photographs.

The greater short-horned lizard is listed as a Montana species “of concern” because its habitat is being altered. According to Barron, the loss of native prairies to agricultural conversion, overgrazing, and fire suppression are the major threats to this secretive little lizard.Bear bullet

Ellen Horowitz is a writer in Columbia Falls.