Green iguana (Iguana iguana) — species profile (taxonomy, geographic range, habitat, physical description, behavior, wild diet, reproduction, lifespan)
Authoritative first-hand species account (Animal Diversity Web, University of Michigan). All bullet facts are verbatim from the cited source and C1-substring verified.
Geographic Range
- Green iguanas, Iguana iguana , occur throughout Central and South America, from Sinaloa and Veracruz, Mexico, south to the Tropic of Capricorn in Paraguay and southeast Brazil.
- This large lizard also inhabits many islands throughout the Caribbean region and the coastal eastern Pacific, and has been introduced into southern Florida and in Hawaii.
- This is the largest known lizard to occur within the borders of the United States (Conant and Collins, 1998; Campbell, 1998).
Habitat
- Green Iguanas are arboreal lizards that live high in the tree canopy.
- Juveniles establish areas lower in the canopies while older mature iguanas reside higher up.
- This tree dwelling habit allows them to bask in the sun, rarely coming down except when females dig burrows to lay eggs.
- Although preferring an arboreal (forested) environment, they can adjust well to a more open area.
Physical Description
- Within three years, a young, 12 gram hatchling iguana can become a 1 kg adult (de Vosjoli, 1992).
- Upon hatching, the length of green iguanas ranges from 17 to 25 cm.
- Most mature iguanas weigh between 4 and 6 kg, but some in South America, with proper diet can reach up to 8 kg.
- These large lizards can reach head to tail lengths of around 2 m.
Behavior
- In the wild, most disputes between iguanas take place over basking sites.
- There is usually adequate food for these herbivorous lizards, but good perches are limited.
- Basking is important for increasing body temperature and aiding digestion.
- During the breeding season, males become territorial and display head bobbing, dewlap extension, and color changes.
- They will bite at each other.
Food Habits (Wild Diet)
- Green iguanas are primarily herbivorous.
- They occasionally eat a small amount of carrion or invertebrates.
- Green leafy plants or ripe fruits are their preferred foods.
- Green iguanas use their tongues to help manipulate the food and bite small enough pieces to swallow, with little or no chewing.
- The food mixes with enzymes in the stomach before moving to the small intestine where pancreatic enzymes and bile are mixed with it.
Reproduction
- Most green iguanas reach sexual maturity between three and four years of age, although maturity can be reached earlier.
- Iguanas tend to breed in the dry season, ensuring that young hatch in the wet season when food is more readily available (de Vosjoli, 1992).
- Mating appears to be polygynandrous.
- Courtship occurs within a defined territory where more than one female may be present.
Development
- Approximately 65 days after mating, a female is ready to lay her eggs.
- The size and number of eggs produced varies depending upon her size, her nutritional status, and her maturity.
- Eggs measure around 15.4 mm in diameter, and 35 to 40 mm in length (Frye, 1995).
Ecosystem Roles
- In addition to helping disperse seeds, iguanas provide a source of food for larger predatory animals, including humans.
- Like other amphibians and reptiles, iguanas can be indicators of environmental changes (Kaplan, 2002).
- Reptiles are more sensitive to environmental changes than are humans, and by watching their responses, we can be alerted to possible problems before they are large enough for us to detect with our own senses.
- Ecosystem Impact disperses seeds
Predation
- One of the best methods for iguanas to avoid predation is their cryptic coloration.
- Because they look like so much of their green environment, they can remain immobile when a predator has been spotted, and go unnoticed themselves.
- Young iguanas may be found in small groups, and use the "selfish-herd" or "more eyes are better" strategy to avoid predators.
Conservation Status
- Although some populations have suffered from poaching and collection for the pet trade, green iguanas are not considered a conservation risk at this time.
- All Iguana species are listed under CITES Appendix II.
- IUCN Red List No special status US Federal List No special status CITES Appendix II Additional Links Encyclopedia of Life Contributors Nancy Shefferly (editor), Animal Diversity Web.
Lifespan
- Iguanas can live for more than 20 years in captivity