Chameleons are well known to most people, easily recognizable by their body shape, independently moving eyes, paw-like hands and feet, and ability to change color rapidly. The main physical features include their diagnostic zygodactyl feet, in which adjacent digits are fused on each hand and foot, forming opposable grasping pads, and the presence of casques, horns, and crests on the heads of most species. They change color easily and quickly, and their eyes, which are on protruding cones, can move independently of one another. Arboreal species have prehensile tails, and most species have laterally flattened bodies. Among the many synapomorphies of this group are extremely extensile tongues (due to modifications of the hyoid apparatus), failure of the pterygoid to meet the quadrate, a reduction in the number of sternal ribs, the loss of both the gular fold and femoral pores, and the V-condition of the ulnar nerve pathway. Like the agamids, but unlike other iguanians, chameleons have acrodont teeth. Chameleons range in size from tiny Brookesia (2.5 cm) to some very large Chamaeleo species (up to 68 cm total length).
Chameleons are diurnal and primarily insectivorous, although birds have been recorded in the diets of some larger species. They can extend their tongues almost the entire length of their body, making their hunting behavior an impressive display. Chameleons exhibit a distinct locomotion in which they slowly rock back and forth between each step taken. Most species are oviparous. In some species (e.g. Furcifer pardalis), females dig holes in sandy soils into which they deposit their fertilized eggs, afterwards covering their tracks, presumably to confuse would-be egg predators. Several of the larger species show distinct sexual dimorphism, with males having larger body size, and elaborate horns and casques, with which they fight. Chameleons are not social animals, and when two animals have visual contact, they can change color within seconds. Depending on species, bright coloration may be restricted to males, found in both sexes, displayed only during the breeding season, or exhibited during aggressive encounters. Male displays may also include head jerking, the spreading of occipital lobes, and gular sac extension
About the animal
All chameleons are found in the Old World, but most live in Madagascar and Africa. The rest are found in the Middle East, a few on islands in the Indian Ocean, and one, the Indian chameleon, in India, Pakistan, and Sri Lanka. Another, the common chameleon, is native to Spain, Portugal, the islands in the Mediterranean Sea, and the Near East. Chameleons live in a variety of habitats, from rain forests and lowlands to deserts, semi-deserts, scrub savannas, and even mountains. Many inhabit trees, but some live in grass or on small bushes, fallen leaves, or dry branches.