Chameleons (family Chamaeleonidae) are a distinctive and highly specialized cladeof lizards. They are distinguished by their parrot-like zygodactylous feet, their separately mobile and stereoscopic eyes, their very long, highly modified, and rapidly extrudable tongues, their swaying gait, the possession by many of a prehensile tail, crests or horns on their distinctively shaped heads, and the ability of some to change color. Uniquely adapted for climbing and visual hunting, the approximately 160 species of chameleon range from Africa, Madagascar, Spain and Portugal, across south Asia, to Sri Lanka, have been introduced to Hawaii, California and Florida, and are found in warm habitats that vary from rain forest to desert conditions. Chameleons are often kept as household pets. The English word chameleon (also chamaeleon) derives from Latin chamaeleō, a borrowing of the Ancient Greek χαμαιλέων (khamailéōn), a compound of χαμαί (khamaí) “on the ground” and λέων (léōn) “lion”. The Greek word is a calquetranslating the Akkadian nēš qaqqari, “Water lion”. The oldest known chameleon is Anqingosaurus brevicephalus from the Middle Paleocene (about 58.7-61.7 mya) of China. Other chameleon fossils include Chamaeleo caroliquarti from the Lower Miocene (about 13-23 mya) of the Czech Republic and Germany, and Chamaeleo intermedius from the Upper Miocene (about 5-13 mya) of Kenya. The chameleons are probably far older than that, perhaps sharing a common ancestor with iguanids and agamids more than 100mya (agamids being more closely related). Since fossils have been found in Africa, Europe and Asia, chameleons were certainly once more widespread than they are today. And since nearly half of all chameleon species today are found in Madagascar, chameleons may originate from there. Monophyly of the family is supported by several studies.