Classification: Introduced Species

Description: The green iguana is a large lizard and is probably the largest species in the iguana family, though a few in the genus Cyclura may match or exceed it in weight. Adults typically grow to 3.9 to 5.6 feet in length from head to tail. As in all iguanas, the tail comprises much of this length, and the snout-to-vent length of most green iguanas is 12 to 17 inches. A typical adult male weighs around 8.8 lbs. while the smaller adult female typically weighs 2.6 to 6.6 lbs. A few large males can reach or exceed 18 lbs in weight and 6.6 feet long. Some specimens have even reportedly been measured at a body weight of greater than 20 lbs.

Despite their name, green iguanas occur in different colours and types. In southern countries of their range, such as Peru, green iguanas appear bluish in colour, with bold blue markings. On islands such as Bonaire, Curaçao, Aruba, and Grenada, a green iguana's colour may vary from green to lavender, black, and even reddish brown. Green iguanas from the western region of Costa Rica are red, and animals of the northern ranges, such as Mexico, appear orange. Juvenile green iguanas from El Salvador are often bright blue, but lose this color as they get older.

Habitat: Green iguanas are diurnal, arboreal, and are often found near water. Agile climbers, Iguana iguana can fall up to 50 feet and land unhurt (iguanas use their hind leg claws to clasp leaves and branches to break a fall). During cold, wet weather, green iguanas prefer to stay on the ground for greater warmth. When swimming, iguanas remain submerged, letting their legs hang limply against their sides. They propel through the water with powerful tail strokes.

While they may often be found in trees, these animals are well-known burrowers. The size of their burrow can range from 1 ft 0 in to 7 ft 10 inchss deep, with a diameter of 4 to 7+3/4 inches. They have been observed burrowing in canals, levees, and dikes and along seawalls in southern Florida. If individuals do not dig their own, they may even use gopher tortoise burrows or usurp those of the Florida burrowing owl.

Range: The green iguana is established on Oahu and Maui, Hawaii, as a feral invasive species, despite strict legislation banning the importation of any reptiles, and in the Rio Grande Valley of Texas. As most reptiles carry Salmonella spp., this is a concern and a reason legislation has been sought to regulate the trade in green iguanas.

Due to a combination of events, the green iguana is considered an invasive species in South Florida, and is found along the east coast, as well as the Gulf Coast, of Florida from Key West to Pinellas County. The original small populations in the Florida Keys were stowaways on ships carrying fruit from South America.

Found in these States: CA | FL | HI | SC | TX

Diet: Green iguanas are primarily herbivores, with captives feeding on leaves such as turnip, mustard, and dandelion greens, flowers, fruit, and growing shoots of upwards of 100 different species of plant. In Panama, one of the green iguana's favorite foods is the wild plum (Spondias mombin).

Although they consume a wide variety of foods if offered, green iguanas are naturally herbivorous and require a precise ratio of minerals (two to one calcium to phosphorus) in their diet. Captive iguanas must have a variety of leafy greens along with fruits and vegetables such as turnip greens, collard greens, butternut squash, acorn squash, mango, and parsnip. Juvenile iguanas often eat feces from adults to acquire the essential microflora to digest their low-quality and hard-to-process vegetation-only diet.

Reproduction: Male green iguanas have highly developed femoral pores on the underside of their thighs, which secrete a scent (females have femoral pores, but they are smaller in comparison to those of the males). In addition, the dorsal spines that run along a green iguana's back are noticeably longer and thicker in males than they are in females, making the animals somewhat sexually dimorphic.

Male green iguanas tend to display more dominant behaviors, such as head bobbing and tail whipping. They also tend to develop a taller dorsal crest than females, as well as taller dorsal spines (or spikes). Large, round, very pronounced jowls are generally a male characteristic. Jowls are located under the jaw and are protected by the subtympanic plate, which is a large, green, circular-shaped scale.

Green iguanas are oviparous, with females laying clutches of 20 to 71 eggs once per year during a synchronized nesting period. The female green iguana gives no parental protection after egg laying, apart from defending the nesting burrow during excavation. In Panama, the green iguana has been observed sharing nest sites with American crocodiles, and in Honduras with spectacled caimans.

The hatchlings emerge from the nest after 10 to 15 weeks of incubation. Once hatched, the young iguanas look similar to the adults in color and shape, resembling adult females more so than males and lacking dorsal spines.

Juveniles stay in familial groups for the first year of their lives. Male green iguanas in these groups often use their own bodies to shield and protect females from predators, and it appears to be the only species of reptile to do this.

Status: The green iguana is listed under Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade is regulated through the CITES permit system. In addition, the green iguana is listed as Least Concern by the IUCN, with a mention of habitat depletion from development being a possible concern for green iguana populations in the future. Historically, green iguana meat and eggs have been eaten as a source of protein throughout their native range, and are prized for their alleged medicinal and aphrodisiac properties. Efforts to raise green iguanas in the past have been made to raise green iguanas in captivity as a food source in an attempt to encourage more sustainable land use in Panama and Costa Rica.

Taxonomy: