Chameleon is the common name for any lizard of the chameleon family (Chamaeleonidae), a family of chiefly arboreal Old World lizards with prehensile tail, independently movable eyeballs, and the ability to change the colour of its skin. It does not change colour in response to its surroundings, as is commonly thought, but rather in response to fear, light, temperature, and other environmental changes.
The chameleon has an amazingly long, sticky tongue, which shoots into the air to catch insects. Its body is unusually shaped, and most chameleons are adapted to living in trees. Its long, thin legs raise it from the ground, and its toes are divided to let it grasp branches like hands, rather than cling like claws. The strong, curled tail is also adapted for grasping. Its body is flattened on the sides, creating a sharp edge on the back, and the skin is rough. Because it has a short neck that cannot turn the eyes are big and "turreted", that is, they can move independently of each other in all directions. Chameleons may be as small as a few centimetres or as large as 63 cm (25 in).