Iguana

The iguana is a type of herbivorous lizard found in tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described by Austrian naturalist J.N. Laurenti in 1768. There are two main species in this genus: the green iguana, which is widespread and often kept as a pet, and the Lesser Antillean iguana, native to the Lesser Antilles.

The name "iguana" comes from the original Taino word iwana. Besides these two species, there are other related lizards also called "iguana" in their common names.

Iguanas are popular pets, and non-native populations have been introduced to many places far from their native homes, including Ishigaki Island, the Florida Peninsula, Hawaii, Singapore, Thailand, Taiwan, and several islands in the Lesser Antilles.

Anatomy and physiology

Iguanas are large lizards that can grow from about 1.2 to 2.0 meters (4 to 6.5 feet) long, including their tails. They have special skin features like a dewlap and special scales along their backs and sides. Their scales vary in shape and color, helping them blend into their surroundings to hide from predators.

Iguanas have excellent vision, allowing them to see shapes, colors, and movement from far away. They also have a tympanum, or eardrum, which helps them hear. As reptiles, iguanas have a three-chambered heart that helps them move quickly for short bursts. Their muscles are light in color because of special fibers that give them quick, powerful movements. Iguanas also have a special parietal eye on the top of their heads that helps them sense changes in light, telling them when it is day or night.

Iguanas eat only plants, and their bodies have adapted to help them chew and digest leaves and other vegetation. They have strong jaws and special teeth that help them grip and cut plant material. During mating season, males show off by bobbing their heads and displaying their dewlap to attract females. After mating, females lay their eggs in nests underground, and the babies hatch after about 85 days.

Phylogeny

The green iguana is part of a group of reptiles called iguanians. These reptiles share special glands that can make toxins. Iguanians, like tuataras, use their tongues to catch food, which is different from most other lizards. They also mainly use their eyes to find food and wait for it to come close before catching it.

There are two main species of iguanas. The green iguana lives in many places, and there are different kinds or subspecies of it in the Caribbean islands. Some scientists think there might be another special kind of green iguana in Curaçao, but more studies are needed to know for sure.

Image	Scientific name	Common name	Distribution
	Iguana delicatissima	Lesser Antillean iguana	The Lesser Antilles on Saint Barth, Anguilla, Sint Eustatius, Guadeloupe, Dominica, and Martinique. Historically inhabited all islands between Anguilla and Martinique, except Saba and Montserrat (and perhaps Redonda).
	Iguana iguana	Green iguana	Most of South America, from Colombia east to French Guiana and south to northern Argentina. Also introduced to parts of the Caribbean. If other species formerly considered conspecific are included, ranges north to southern Mexico and the southern Caribbean; specifically Grenada, Aruba, Bonaire, Curaçao, Trinidad and Tobago, St. Lucia, St. Vincent, Saba (island), Montserrat and Útila.

Image	Subspecies	Common name	Distribution
	I. i. insularis	Grenadines horned iguana	St. Vincent and the Grenadines and Grenada
	Iguana iguana melanoderma	Saban black iguana	Saba, Montserrat, and formerly Redonda, but also possibly coastal Venezuela, the Virgin Islands, and Puerto Rico. At least parts of this range may derive from historic introduction.
	I. i. sanctaluciae	Saint Lucia horned iguana	St. Lucia

As food

Iguanas have been a part of the food traditions in Mexico and Central America for a long time. In some places, like the Dominican Republic, Puerto Rico, Nicaragua, and Colombia, people also eat iguana meat and even iguana eggs.

Ecology

Iguanas are important in the ecosystems where they live, especially on islands. As large herbivores, they eat leaves, flowers, fruits, and seeds, which helps plants grow and spread their seeds. The many eggs that female iguanas lay provide food for animals that eat eggs or baby iguanas. The tunnels that female iguanas dig for their nests also create spaces underground that other animals can use. For example, the Lesser Antillean iguana can dig nests as deep as 1.65 m (5.5 ft).