One neat thing about many in the Lizard Family is that they can walk up walls. At the right you see the bottom of a foot of a Green Anole, Anolis carolinensis. There are no suction cups or glue-spots on the foot, so what makes the foot stick to walls?. The enlarged toe pads clearly visible in the picture are equipped with millions of microscopic hooks that grip irregularities in surfaces. Geckoes have a different wall-climbing system. Their feet bear scales covered with jillions of microscopic hairlike bristles, and at the tip of each bristle is a minute suction cup...
The species most frequently making it into average U.S. backyards are:
You might be interested in browsing Naturalist Jim Conrad's lizardy notes accumulated during years of travel in lizardy places.
For more background information on lizards, check out these links:
The only poisonous lizard in North America is the Gila Monster, restricted to the Desert Southwest. With its very thick body and wide bands running crosswise, it's not likely to be mistaken for anything else. Therefore, in North America our backyard lizards can be considered as completely safe -- as long as we're not in Gila Monster territory.
However, be forewarned that a number of species, when caught, shed their tails. As the tail writhes furiously, the lizard escapes. Of course this is an adaptation to confuse and shock the enemy -- which is does very well! Backyard naturalists roaming beyond their backyards should remember never to handle any animal whose behavior they don't understand.
Lizardy books available at Amazon.com in both the US and UK can be reviewed here.
On the Web, check out The Lizard Lounge, specializing in lizard care.