Andy, I have a similar shot in my album which you commented on...same species of lizard, same location (Porcupine Rim, Moab, Utah), same impression: they sure are tame, to let us creep up on them, take macro photos of them, and even pet them! You'd think that evolution would have given them a flight reflex when we approach. Maybe we happen to be good-looking humans!
Yeah Kendog. I noticed your similar photo. Lizards are so rare over here and it was amazing to get so close to one. In Fruita I was riding with my son and he was infront of me. He slammed his anchors on when he saw one of these and I crashed into the back of him!!
With regard to evolution, maybe they have seen so may bikers on that porcy rim trail they aren't seeing us as a threat anymore. Adaption!