Most of the anoles in the Greater Antilles (Puerto Rico, Hispaniola, Cuba, and Jamaica) are considered to be in one of six "ecomorphs". Species are considered to be the same ecomorph if they have the same structural habitat or niche (e.g. tree trunks, canopy, grasslands), and are similar physically and behaviorally. They do not need to be closely related; in fact, the single most interesting fact about anoles is that they have evolved into these six ecomorphs separately on each of these four islands. (One of the ecomorphs is found on only two of the four islands, and another is found on three islands. The other four ecomorphs are found on all four islands.)

Anolis evermanni is considered a "trunk-crown" species. The species in this ecomorph tend to live, as you might guess, on tree trunks and upper branches. They are graceful and agile, hunting bugs by moving stealthily through the branches. They are typically green, to match the leafy background up in the trees. The only native U.S. anole, Anolis carolinensis, is also considered a trunk-crown species. If you want to learn more about ecomorphs and anoles in general (and who doesn't?), you should read Jonathan Losos's most excellent book Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles.

After such a highfalutin introduction, I should note that this particular lizard was not on a tree at all, but on the handrail of a bridge at El Yunque National Forest's visitor center.