Chameleons are a distinctive and highly specialized clade of Old World lizards with 202 species described as of June 2015. These species come in a range of colors, and many species have the ability to change color.
Change of color
Some chameleon species are able to change their skin coloration. Different chameleon species are able to vary their coloration and pattern through combinations of pink, blue, red, orange, green, black, brown, light blue, yellow, turquoise, and purple.
Color change has functions in camouflage, but most commonly in social signaling and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Color change signals a chameleon’s physiological condition and intentions to other chameleons. Chameleons tend to show brighter colors when displaying aggression to other chameleons, and darker colors when they submit or “give up”.
While the exact evolutionary history of color change in chameleons is still unknown, there is one aspect of the evolutionary history of chameleon color change that has already been conclusively studied: the effects of signal efficacy. Signal efficacy, or how well the signal can be seen against its background, has been shown to correlate directly to spectral qualities of chameleon displays. It was demonstrated that chameleons in brighter areas tended to present brighter signals, but chameleons in darker areas tended to present relatively more contrasting signals to their backgrounds. This finding suggests that signal efficacy (and thus habitat) has affected the evolution of chameleon signaling.
Image: By Yathin S Krishnappa – Own work, CC BY-SA 3.0
Text: Wikipedia contributors. “Chameleon.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 25 Aug. 2017. Web.