The horns on a chameleon are made up of ringlike segments of inner bone covered by a hard keratin-like skin.
Chameleons change color by rearranging a lattice of nanocrystals in one of their top layers of skin cells called iridophores. Chameleons can then stretch this layer, broadening the nanocrystalline lattice, thereby causing it to reflect a different wavelength of light.
True chameleons include the following genera: Archaius, Bradypodion, Brookesia, Calumma, Chamaeleo, Furcifer, Kinyongia, Nadzikambia, Palleon, Rhampholeon, Rieppeleon and Trioceros.
Chameleons have a very poor sense of smell.
Chameleons can project their tongue up to 2.2 times their body length.
Pygmy chameleons have bicuspid claws where each claw has two points like a crescent moon.
There are currently 202 recognized chameleon species and 85 of them are found on the island of Madagascar.
Chameleons do not have external ears or a tympanic membrane, but they do have internal ears as well as degenerated middle ears. They do not hear well but they can detect low frequency sounds.
The word Calumma comes from the Latin word for covering. This genus consists of chameleons from Madagascar with occipital lobes.
Many chameleon species have a bright red, orange or yellow mouth. This conspicuous interior when displayed is used as a defense against predators.