Iguana, a large lizard of tropical America. The largest iguanas attain a length of about six feet (1.8 m), over half of which is tail. The iguana has black, brown, or green scales. A spiny ridge extends down its back and a dewlap (skin flap) hangs from its throat. Some species live in trees near the water, others are ground dwellers. All are good swimmers. Iguanas live chiefly on fruit, vegetation, and birds' eggs. Both the flesh and the eggs of iguanas are eaten.

IguanasIguanas eat insects, fruit, flowers, and leaves.

The grayish-green common iguana is the largest species. The horned rhinoceros iguana lives in the West Indies. The marine iguana lives in the Galápagos Islands off Ecuador.

What Is a Lizard?

A lizard is a reptile. Reptiles are animals that are cold-blooded vertebrates. Cold-blooded animals do not control their own body temperature, their temperature is determined by the temperature of their surroundings. And, vertebrates are animals with a backbone.

Lizards, which are closely related to snakes, vary in size, shape, and color. Lizards’ bodies are covered with scales. Each scale is a piece of thickened skin that helps protect lizards from attackers. These scales also limit the loss of heat and moisture from the lizard’s body.

Where in the World Do Iguanas and Other Lizards Live?

Iguanas live in an area that stretches from southern Canada south to Argentina. A few species live on the island of Madagascar in the Indian Ocean and on the islands of Fiji and Tonga in the Pacific Ocean.

Lizards live almost everywhere except the areas near the North and South poles. They are most often found in the tropics and in warm parts of the temperate zones. These zones are the two regions of Earth between the tropics and the polar circles.

Lizards are the most common reptiles found in deserts and other dry regions. When the desert becomes too hot for comfort, lizards lie in the shade or under the sand to escape the sun’s rays.

How Do Iguanas and Other Lizards Get Around?

Most iguanas and other lizards get around by walking on their four legs. But, two types of iguana, the collared lizard of the southwestern United States and Mexico and the basilisk (BAS uh lihsk) of Mexico and Central America, can run using only two of their four legs. They raise the front of their body and run using their hind legs. Some basilisks can even run on water. A fringe of skin around their toes lets them skim the water’s surface.

Another kind of lizard, the fringe-toed lizard, lives in the deserts of the southwestern United States and northwestern Mexico. These animals have a comblike fringe on their toes to help them run across the loose surface of the sand.

No present-day lizards can fly, but a small group called flying dragons comes close to doing that. They glide from tree to tree, as flying squirrels do. Flying dragons can spread out a fold of skin along either side of their body. They do this by moving several long ribs that support this fold of skin. This creates a “wing” that lets them sail short distances through the air.