Found these two together- possibly mating? One of them was found belly-up, with its foot caught between a small rock and a dirt wall. It was wiggling and trying to free itself from the spot it had apparently fallen into. The second one was sitting normally, about 4 inches away.

The male had dried blood on his face (presumably squirted from his eyes- no injuries noted). I don't know if the blood was from a previous incident or related to this encounter with the female. Do horned lizards ever use blood in courtship or non-canine defense?