A chameleon is a lizard of the family Chamaeleonidae. Most species are arboreal, although some are terrestrial. They range in size from 10 cm (4 in) to over 60 cm (2 ft). The majority of chameleons live in tropical or subtropical regions of Africa, Madagascar, southern Europe and across southern Asia as far as Sri Lanka. A few species are found in northern Europe and even North America.
Chameleons have zygodactylous feet: the first toe on each foot points inward (opposable), while the other toes point forward. This arrangement enables them to grip onto branches securely with two toes pointing in opposite directions. Most also have prehensile tails which they use for climbing and balancing themselves on thin twigs and branches; some have laterally compressed tails which they use like a pole when moving about on narrow surfaces such as tree bark or leaves that would otherwise be too slippery to walk upon directly.
Chameleons can change their coloration depending on temperature, light intensity, mood, health status, and camouflage requirements. Some chameleons also change color when they are angry or excited. Color changes usually take place gradually rather than instantly; a single chameleon may contain several hues at once before finally settling into its new shade(s).
There are approximately 160 different species of chameleon currently recognized by taxonomists; however, this number will likely increase as more research is conducted on these fascinating reptiles.