The green iguana is one of the largest and most widely recognized lizards in the Americas, a tree-dwelling herbivore whose range stretches from southern Mexico to the subtropics of South America [Scott et al. 2020]. It is at once a flagship of Neotropical forest canopies, a heavily traded reptile in the global pet market, and — beyond its native range — one of the most consequential invasive vertebrates of warm coastal regions. This profile examines the species' biology, its native and introduced distribution, its conservation standing, and the programs working both to sustain wild populations and to manage introduced ones.
Biology and Identification
The green iguana is a large, diurnal, arboreal lizard. Including the tail, adults commonly reach 1.2–1.7 m in total length, and exceptional individuals exceed 2 m; the tail accounts for roughly half or more of that length. Body mass is strongly sexed, with mature males typically heavier than females and the largest males reaching several kilograms [Scott et al. 2020]. Despite the common name, coloration is variable — ranging from bright green in juveniles to grey, brownish, or orange tones in adults and breeding males.
Distinctive features include a crest of elongated dorsal spines running from the nape along the back, a prominent throat fan (dewlap) used in display and thermoregulation, and a large rounded scale (the subtympanic plate) below the ear opening. On the top of the head lies a parietal eye, a light-sensitive photoreceptive organ connected to the pineal complex that contributes to the regulation of circadian and basking behaviour [Tosini & Menaker 1998].
The species is predominantly herbivorous, feeding selectively on leaves, shoots, flowers, and fruit, with seasonal switching among food plants documented in wild populations [van Marken Lichtenbelt 1993]. As an ectothermic herbivore it depends on behavioural thermoregulation and microbial hindgut fermentation to process fibrous plant material; digestive efficiency is closely tied to body temperature, and food intake and digestion explain much of the variation in field body temperatures recorded in wild iguanas [van Marken Lichtenbelt 1992; van Marken Lichtenbelt et al. 1997]. Females are highly fecund, with mean clutch size near 35 eggs in many populations, deposited in excavated nest burrows [Scott et al. 2020].
Habitat and Range
The green iguana's native range extends from northern Mexico (Sinaloa and Veracruz) south through Central America and into South America as far as Paraguay and southeastern Brazil, together with numerous Caribbean islands [Scott et al. 2020]. It is strongly associated with lowland tropical and gallery forest, mangroves, and riverine vegetation, and is rarely found far from water, into which it readily drops and swims when threatened.
Beyond its native distribution, the species has established self-sustaining introduced populations in South Florida, Puerto Rico, Hawaii, and parts of Texas, as well as in Taiwan, Hong Kong, Singapore, and other warm regions, largely as a consequence of the international pet trade [Claunch et al. 2025; Liu et al. 2026]. In Florida, where iguanas have been established since 1966, populations have been reported across dozens of counties and can reach high local densities [Claunch et al. 2025].
In accordance with NRWL sensitive-species policy, specific breeding-site locations, communal nest-burrow coordinates, and seasonal movement details are not disclosed in this article.
Conservation Status
The green iguana is assessed as Least Concern on the IUCN Red List, an amended 2020 assessment of the species [Scott et al. 2020]. The listing reflects the species' very wide distribution, large overall population, presumed large numbers, and tolerance of disturbed habitats — including its capacity to expand within introduced ranges. The species is included on CITES Appendix II, under which international commercial trade is regulated through a permit system rather than prohibited [CITES 2023].
A Least Concern global category does not mean the species is free of pressure. Localized declines have been documented in parts of Central and South America where adults and nesting females are intensively harvested for meat and eggs, and where collection for the pet trade is concentrated [Stephen et al. 2011]. Conversely, in its introduced range the same adaptability that secures its global status makes it a damaging invasive species, creating what researchers describe as a conservation-versus-biosecurity paradox: a CITES-listed species that is simultaneously a target of control programs [Liu et al. 2026].
Threats
Harvest for meat and eggs. Across much of Central and South America, green iguanas are hunted for human consumption, with gravid females especially targeted for their eggs. Sustained, unregulated offtake can depress local populations even where the species remains widespread regionally [Stephen et al. 2011].
Pet and leather trade. The green iguana is among the most heavily traded reptiles in the world; large volumes of live animals and skins have moved through legal and illegal markets, and high market demand continues to drive collection from the wild [Stephen et al. 2011; Liu et al. 2026].
Habitat loss. Conversion of lowland tropical forest, gallery forest, and mangrove for agriculture and development removes the canopy habitat and riverside nesting substrate the species depends on within its native range [Scott et al. 2020].
Invasive-population management pressures. In introduced ranges, the species is a target of removal and control because of damage to horticulture, infrastructure, and native ecosystems, including burrowing that undermines structures and consumption of imperiled native plants [Claunch et al. 2025].
What Is Being Done
Trade regulation. The CITES Appendix II listing requires that international trade be accompanied by permits and non-detriment findings, providing the principal legal mechanism for monitoring and limiting commercial exploitation [CITES 2023].
Sustainable-use and head-starting programs. Captive-rearing and "head-starting" initiatives — in which eggs or hatchlings are reared and later released — have operated in several Central American countries, sometimes paired with community iguana husbandry intended to provide a sustainable protein source and reduce pressure on wild populations. Reviews note these programs vary in measurable conservation benefit and require careful evaluation [Stephen et al. 2011].
Status assessment and research. Authoritative status tracking is maintained through the IUCN Red List and the IUCN SSC Iguana Specialist Group, and a growing body of field research on the species' physiology, foraging, and reproduction informs management across both native and introduced ranges [Scott et al. 2020; van Marken Lichtenbelt et al. 1997].
Invasive-species management. In Florida and other introduced ranges, wildlife agencies maintain monitoring and control frameworks; in Florida the species is designated Prohibited and may be removed under defined rules on private and certain public lands [FWC 2024; Claunch et al. 2025].
How Readers Can Help
Responsible pet ownership. Never release captive iguanas into the wild. Released or escaped pets are the principal source of damaging introduced populations, and rehoming through reputable channels is the responsible alternative to release [Claunch et al. 2025].
Support regulated, traceable trade. Where iguanas or iguana products are legally available, favor sources that comply with CITES permitting, and avoid wild-caught animals of uncertain origin [CITES 2023].
Citizen science. Record and report wildlife observations through platforms such as iNaturalist or, in introduced ranges, through state reporting tools. Verified records support both range mapping for native populations and early detection of new introductions [FWC 2024].
Education and policy engagement. Share accurate information about the green iguana's dual role — a native species of conservation interest in Latin America and the Caribbean, and an invasive species elsewhere — and support science-based management and habitat-protection policies in both contexts [Liu et al. 2026].
References
[CITES 2023] CITES. (2023). Appendices I, II and III. Convention on International Trade in Endangered Species of Wild Fauna and Flora. https://cites.org/eng/app/appendices.php
[Claunch et al. 2025] Claunch, N.M., Jones, P.M., Khazan, E.S. & Kluever, B.M. (2025). State of knowledge for invasive green iguanas in Florida reveals negative impacts and pervasive research needs. Frontiers in Amphibian and Reptile Science, 3, 1529065. https://doi.org/10.3389/famrs.2025.1529065
[FWC 2024] Florida Fish and Wildlife Conservation Commission. (2024). Green Iguana (Iguana iguana) species profile and management information. https://myfwc.com/wildlifehabitats/profiles/reptiles/lizards/green-iguana/
[Liu et al. 2026] Liu, D., Xie, C., Hou, S. & Xue, X. (2026). The green iguana paradox: balancing conservation, trade and ecological security in invasive species management. Environmental Conservation (published online 7 January 2026). https://doi.org/10.1017/S0376892925100301
[Scott et al. 2020] Scott, N., Solórzano, A. & Sunyer, J. (2020). Iguana iguana (amended version of 2018 assessment). The IUCN Red List of Threatened Species 2020: e.T174481A174437922. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T174481A174437922.en
[Stephen et al. 2011] Stephen, C., Pasachnik, S., Reuter, A., Mosig, P., Ruyle, L. & Fitzgerald, L. (2011). Survey of Status, Trade, and Exploitation of Central American Iguanas. U.S. Department of the Interior, U.S. Fish and Wildlife Service, Washington, D.C. https://www.researchgate.net/publication/271443622_Survey_of_Status_Trade_and_Exploitation_of_Central_American_Iguanas
[Tosini & Menaker 1998] Tosini, G. & Menaker, M. (1998). Multioscillatory circadian organization in a vertebrate, Iguana iguana. The Journal of Neuroscience, 18(3), 1105–1114. https://doi.org/10.1523/JNEUROSCI.18-03-01105.1998
[van Marken Lichtenbelt 1992] van Marken Lichtenbelt, W.D. (1992). Digestion in an ectothermic herbivore, the green iguana (Iguana iguana): effect of food composition and body temperature. Physiological Zoology, 65(3), 649–673. https://doi.org/10.1086/physzool.65.3.30157975
[van Marken Lichtenbelt 1993] van Marken Lichtenbelt, W.D. (1993). Optimal foraging of a herbivorous lizard, the green iguana in a seasonal environment. Oecologia, 95(2), 246–256. https://doi.org/10.1007/BF00323497
[van Marken Lichtenbelt et al. 1997] van Marken Lichtenbelt, W.D., Vogel, J.T. & Wesselingh, R.A. (1997). Energetic consequences of field body temperatures in the green iguana. Ecology, 78(1), 297–307. https://doi.org/10.1890/0012-9658(1997)078[0297:ECOFBT]2.0.CO;2