We were pulling our little RV onto the dirt road at Agua Fria National Monument, looking for a good place to camp with our dogs, when I spotted a lizardy motion ahead. This grumpy-looking horned lizard had made the mistake of moving. If it had remained still, there's no way I would have noticed it. I hollered "that's a horned lizard!" and Monica quickly stopped so I could rush out for a photo session.

Regal horned lizards are the largest U.S. species of horned lizard (Mexico, where all non-U.S. horned lizard species live, features the Giant Horned Lizard, Phrynosoma asio). One of the distinguishing features of Regal horned lizards is the set of four equally-spaced equally-long horns on the back of the head.

I was really hoping to find one or more of Mexico's endemic horned lizards, especially the Rock Horned Lizard, on this trip. Alas, it was not to be. But my consolation prize was a pair of beautiful Regal Horned Lizards that we saw on the road in the late afternoon, no more than fifteen minutes apart.