This is one of the many wild iguanas living in South Florida. This iguana was photographed in a vacant lot next to a canal, in Pompano Beach. The two species of lizard within the genus Iguana possess a dewlap, a row of spines running down their back to their tail, and a third "eye" on their head. This eye is known as the parietal eye, visible as a pale scale on the top of the head. Behind their neck are small scales which resemble spikes, known as tuberculate scales. These scales may be a variety of colors and are not always visible from close distances. They have a large round scale on their cheek known as a subtympanic shield.
Iguanas have excellent vision and can see shapes, shadows, colors and movement at long distances. They use visual signals to communicate with other members of the same species. Photo Copyright 2005 Robert Giordano.
Description from Wikipedia