Iguana vs Chameleon: Key Differences Between These Lizards

Key differences at a glance

Iguanas and chameleons are both lizards, and both belong to a larger group called Iguania, which also includes agamas and anoles. But they belong to different families and have taken very different paths. Iguanas (family Iguanidae) are mostly large herbivores. Chameleons (family Chamaeleonidae) are specialized tree-dwelling predators whose closest relatives are the agamid lizards of the Old World.

This comparison focuses on the green iguana and the veiled chameleon, the two species most people mean when they say “iguana” or “chameleon.” Both are well known and both have become established outside their native ranges.

Size: which is bigger?

The iguana is far bigger. Adult green iguanas typically reach 1.2–1.7 m (4–5.6 ft) from nose to tail tip, with large males occasionally reaching 2 m (6.6 ft). Males usually weigh about 4 kg (9 lb), and exceptional ones reach 8 kg (18 lb) or more.

Male veiled chameleons, among the larger chameleons, measure about 43–61 cm (17–24 in) including the tail, and females are usually no more than about 35 cm (14 in). Across the whole chameleon family, sizes range from tiny Brookesia chameleons of Madagascar, some barely 2–3 cm (about 1 in) long, to Oustalet’s chameleon at up to about 68 cm (27 in). Even the largest chameleon weighs only a small fraction of a big iguana.

Where do they live?

Iguanas are New World lizards. Green iguanas are native from Mexico through Central America to Paraguay and southern Brazil, and on many Caribbean islands. They live in humid lowland forest, mostly in trees close to rivers, lakes and coasts.

Chameleons are Old World lizards. About half of the roughly 200 species live only on Madagascar, and most of the rest are found in mainland Africa. A few live in the Middle East and southern Asia as far as India and Sri Lanka, and one, the common chameleon, reaches southern Europe in Spain, Portugal, Malta, Greece and Cyprus. The veiled chameleon comes from the dry mountain slopes, plateaus and valleys of Yemen and southwestern Saudi Arabia.

The two meet only where people have introduced them. Both green iguanas and veiled chameleons have wild populations in Florida and Hawaii, descended from escaped or released pets.

What do they eat?

This is the most important ecological difference. Green iguanas are herbivores that eat leaves, flowers, fruit and shoots, relying on gut microbes to break down plant fiber.

Chameleons are insectivores. They hunt by sitting still or creeping slowly along branches, spotting prey and then firing out their tongue. Crickets, grasshoppers, flies, moths, mantises and other insects are typical prey, and large chameleon species can catch small lizards or birds. The veiled chameleon is unusual in also eating some leaves, probably mainly as a source of water during the dry season.

Eyes and tongues

Chameleon eyes are among the most unusual in the animal kingdom. The eyelids are fused into a cone with only a small opening for the pupil, and each eye can rotate and focus on its own. A chameleon can look forward with one eye and backward with the other, then lock both eyes onto prey to judge distance. See How do chameleon eyes work?.

Iguanas have ordinary lizard eyes with movable lids and good color vision. They also have a parietal eye, a small light-sensing organ on top of the head that detects shadows and changes in brightness; read Do iguanas have a third eye?.

The chameleon tongue is a ballistic weapon. It is launched by elastic tissues and muscles, can extend farther than the length of the chameleon’s body, and hits prey in a fraction of a second with a sticky, suction-cup-like tip. The iguana’s tongue is short and fleshy and is used for handling food and tasting its surroundings. More in How fast is a chameleon’s tongue?.

Feet, tails and how they move

A chameleon’s toes are fused into two opposing bundles on each foot, forming a tong-like grip around thin branches. Its tail is prehensile, meaning it can curl around twigs like an extra hand. Chameleons move slowly with a swaying gait that may help them look like leaves moving in the breeze. Unlike many lizards, they cannot shed and regrow their tail.

Iguanas have five separate, long-clawed toes on each foot, which are good for climbing bark, running and digging. Their long, whip-like tail is used for balance, swimming and defense, and like many lizards they can drop part of it to escape a predator and later grow a shorter replacement. Green iguanas are fast runners and strong swimmers, and they can survive falls of up to about 15 m (50 ft).

Color change

Chameleons are famous for changing color, and some species do it in seconds. The changes are made by special skin cells containing tiny crystals that reflect different colors of light as the spacing between them changes. Chameleons change color mainly to signal mood, rank and readiness to breed, and to manage body temperature, more than to match their background. Learn more in Why do chameleons change color?.

Green iguanas can change shade too, but slowly and less dramatically. They look darker when cool, paler in the heat, and many breeding males turn orange or golden for several weeks.

Reproduction and lifespan

Green iguanas breed once a year. The female lays a clutch of usually a few dozen eggs, from about 10 to 70, in a burrow and leaves; the eggs hatch after roughly 10–17 weeks. Iguanas usually first breed at 2–4 years old.

Veiled chameleons mature fast, in as little as 4–5 months, and a female may lay clutches of about 35–85 eggs up to three times a year. Their lives are short: about 5 years for females and up to 8 years for males. Some other chameleons, such as Jackson’s chameleon of East Africa, give birth to live young instead of laying eggs.

Wild green iguanas live about 8 years on average and can exceed 20 years in captivity.

Can iguanas and chameleons interbreed?

No. They belong to different families that separated many millions of years ago, so they cannot produce offspring together. Any picture of an “iguana-chameleon hybrid” shows either one species or the other, or is digitally altered.