Most of the Arizona Sonoran Desert Museum grounds are outdoors, and a variety of native and non-native species live wild there. This young spiny lizard was clinging to a boulder along the main trail through the outdoor part of the museum.

This very large and very dark individual tried to hide behind the tree trunk it was perched upon by constantly shuffling to stay on the opposite side of me. Eventually it decided on the safety of some nearby boulders, and I got just a couple of poor photos as it scurried away.

These robust spiny lizards were fairly common in the trees lining the San Pedro river, though they're wary and difficult to approach. Youngsters and females are dark and camouflaged well on tree trunks. Some of the large males are very light with extremely pronounced black collars. We saw two pairs of large adults on different trees, and several individuals scattered about. Unfortunately all the large light-colored males raced up the tree trunks before I could get a decent picture. The sneaky-looking fellow in this picture gives you a hint of the dramatically different appearance of these large males.

This big male spiny lizard occupied a rock a few feet away from a big female spiny lizard. She was enough shyer that I didn't end up with any photos, but he was a lot prettier anyway.

While whiling away the oh-so-hot midday hours in anticipation of some exciting nocturnal herping, I chased around a bunch of S. clarkii before I could get one or two of them to stay in place for a few moments.

I hiked Alamo Canyon this morning specifically to look for Sonoran Collared Lizards. The first lizards I saw were a bunch of Zebra-tailed Lizards, which are much smaller and thinner than collared lizards, and which are typically on the desert floor whereas collared lizards are typically up on boulders. Then in the distance I saw a large, thick lizard up on a boulder, and whipped out my binoculars. Collared lizard? Hmm? But no! It was just a Sonoran Spiny Lizard, an easily-found species that I had seen many times before. Still, a reasonably cool lizard.

But do not fret for me. I did eventually find my quarry that morning. (Oh, you weren't fretting for me? Well, you should have been.)

I had seen this lizard repeatedly on a rock pile at the edge of a parking lot, but it had ducked into the gaps between the rocks whenever I got remotely near. I eventually got this photo with a 300mm lens shooting from inside my car.

Sceloporus nelsoni, a Mexico endemic that I have never seen, had been seen by Matt Cage many times in this area, including earlier on this day. When I saw a Sceloporus lurking in the shade on a boulder, I was momentarily excited. Alas, it was just another Sceloporus clarkii.

Matt spotted this poor fellow trapped in a smooth-concrete-lined pit. It had about 100 square feet of habitat in there, which was clearly not enough to support a healthy quantity of prey items, as this was one weak, emaciated lizard. But not so weak and emaciated that it couldn't try to evade rescue, and then bite my finger and refuse to let go even after I let it down gently on a nearby boulder. I had to squeeze its jaws a little to get it to let go.

Our final herp of &AAcute;lamos, this sub-adult was perched on a short concrete barrier in the parking area at Rancho Acosta. We saw it as we started to drive out, and stopped for a quick photo session.

I originally mistook these lizards for Desert Spiny Lizards, because I didn't realize that Clark's Spiny Lizards lived this far north. But it turns out that both species live in the red rock desert around Sedona, and the ones I photographed were definitely Clark's. One way to distinguish them is by the dark bands on the forearms, visible in the second photograph here.