Anoles are small lizards in the genus Anolis (family Iguanidae), found only in the Americas, mostly in the tropical countries. Because anoles can change the color of their skin according to their mood, temperature, humidity, and light intensity, these animals are sometimes called chameleons. However, none of the more than 300 species of anoles is closely related to the true chameleons (family Chamaeleonidae) of Eurasia and Africa.
Aggressive encounters and defense responses to predators prompt the extension of the throat fan, or dewlap, of male anoles. This stereotyped visual display is often accompanied by a vigorous demonstration of head-bobbing, the frequency and amplitude of which are important among anoles in species recognition.
Because anoles spend a great deal of time engaged in displays and other activities associated with holding their breeding territory, the males are at a relatively greater risk of predation than the more inconspicuous females. However, the greater risks of predation are balanced by the better reproductive success a male anole may achieve during the period of his life that he is able to hold a high-quality territory.
The green anole (Anolis carolinensis) is the only species native to North America, occurring in the southeastern United States, and also in Cuba and nearby islands. The green anole does not hibernate, and is active on warm, sunny days throughout the winter, remaining inactive in a sheltered place on colder days. The usual color of these animals is brown, but male animals quickly become green when they are engaged in aggressive encounters with other males, or when they are courting a female.
Four additional species of anoles have been introduced to Florida from their natural ranges in the West Indies or Central America. These are the brown anole (Anolis sagrei), the large-headed anole (A. cybotes), the bark anole (A. distichus), and the knight anole (A. equestris). Although these species are not part of the native fauna of Florida, they are now entrenched components of that state's ecosystems as are many other introduced species of plants and animals.