Chameleon

Colour change

The popular belief that chameleons change colour for camouflage is only partially correct. Chameleons change colour primarily to communicate — signalling aggression, submission, and mating readiness to other chameleons. The mechanism is unusual: they don’t change pigment chemistry but alter the spacing of nanocrystals (iridophores) in their skin, which changes which wavelengths of light are reflected. Males display the brightest and most rapid colour changes; females and juveniles have more muted palettes.

Ballistic tongue

The chameleon’s tongue is a projectile weapon. Coiled in the mouth like a compressed spring, it launches at up to 13 km/h, extending to 1.5–2 times the body length, and strikes the target with a sticky, mucous-coated tip within 0.07 seconds. The strike is powered by elastic energy stored in collagen fibres around the tongue muscle — the same principle as a bow and arrow. It can capture insects, small lizards, and even birds.

Eyes and vision

Each chameleon eye can rotate independently through 360 degrees in both horizontal and vertical planes, providing complete panoramic vision without moving the head. The two eyes typically scan different sectors independently; when prey is spotted, both eyes converge on the target to provide the stereoscopic depth perception needed for the tongue strike.

Madagascar diversity

Madagascar is the centre of chameleon diversity — over two-thirds of the world’s chameleon species (around 150 of the 220 known species) live there and nowhere else. The island’s isolation allowed chameleons to diversify into an extraordinary range of forms, from the giant Parson’s chameleon (60 cm) to the Brookesia micra (under 30 mm), one of the smallest reptiles in the world.