What primarily drives the color shifts in the green anole's skin, contrary to common assumption?

Internal states like aggression or immediate environmental stress

While the anole's color change is famous, the shift between green and brown/gray hues is not solely dictated by matching the immediate background substrate. The primary catalysts for these changes stem from internal physiological conditions or immediate environmental pressures. For instance, a male engaging in territorial confrontation or excitement will often darken to a brownish hue regardless of the surface color. Similarly, thermoregulation plays a vital role; cold lizards darken to maximize solar radiation absorption for warming up quickly. Thus, the current hue is often a better indicator of the lizard's current activity level, emotional state, or temperature needs rather than strict visual camouflage.