The one thing everyone knows about chameleons is that they change color. The lizards’ palette-changing tricks have sparked human curiosity since the days of ancient Greece, when Aristotle first hypothesized that chameleons’ colors were linked to their mood or emotions. A century later, Antigonus of Carystus put forth another idea—chameleons change color to match their surroundings and hide from predators.
http://www.mentalfloss.com/blogs/archives/82259