This is a Carolina anole, or green anole, in De Soto National Forest, Mississippi. Like chameleons, they can change from this bright green color to a brown. Their color is largely determined by body temperature, stress, and activity level - bright green relates to bright light, being warm, low stress, and active. They also have a beautiful blue color surrounding their eyes if you look closely. Males also have an orange/red dewlap (throat fan) which is used in territorial displays.