# About the Igunana **URL:** https://reptilecommunity.com/t/about-the-igunana/50 **Category:** Igunana **Created:** [July 18, 2025, 12:55pm UTC](https://reptilecommunity.com/t/about-the-igunana/50 "2025-07-18T12:55:25Z") **Posts on this page:** 1 **Page:** 1
### Author: ![ReptileCommunity](https://reptilecommunity.com/user_avatar/reptilecommunity.com/reptilecommunity/32/3_2.png) [@ReptileCommunity](https://reptilecommunity.com/u/ReptileCommunity) #### Post date: [July 18, 2025, 12:55pm UTC](https://reptilecommunity.com/t/about-the-igunana/50/1 "2025-07-18T12:55:25Z")
_ **Iguana** _ ([/ɪˈɡwɑːnə/](https://en.m.wikipedia.org/wiki/Help:IPA/English),[[4]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-cambridge1115-4)[[5]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-oxford5632-5) Spanish: [[iˈɣwana]](https://en.m.wikipedia.org/wiki/Help:IPA/Spanish)) is a [genus](https://en.m.wikipedia.org/wiki/Genus) of [herbivorous](https://en.m.wikipedia.org/wiki/Herbivorous) [lizards](https://en.m.wikipedia.org/wiki/Lizard) that are native to tropical areas of Mexico, [Central America](https://en.m.wikipedia.org/wiki/Central_America), South America, and the [Caribbean](https://en.m.wikipedia.org/wiki/Caribbean). The genus was first described by Austrian [naturalist](https://en.m.wikipedia.org/wiki/Naturalist) [J.N. Laurenti](https://en.m.wikipedia.org/wiki/Josephus_Nicolaus_Laurenti) in 1768.[[6]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-6) Two [species](https://en.m.wikipedia.org/wiki/Species) are placed in the genus: The [green iguana](https://en.m.wikipedia.org/wiki/Green_iguana), which is widespread throughout its range and a popular pet; and the [Lesser Antillean iguana](https://en.m.wikipedia.org/wiki/Lesser_Antillean_iguana), which is native to the [Lesser Antilles](https://en.m.wikipedia.org/wiki/Lesser_Antilles). Genetic analysis indicates that the green iguana may comprise a [complex](https://en.m.wikipedia.org/wiki/Species_complex) of multiple species, some of which have been recently described, but the [Reptile Database](https://en.m.wikipedia.org/wiki/Reptile_Database) considers all of these as subspecies of the green iguana.[[7]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Breuil2020-7)[[8]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Iguana_iguana-8) The word “iguana” is derived from the original [Taino](https://en.m.wikipedia.org/wiki/Ta%C3%ADno_people) name for the species, _iwana_.[[9]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Coles-9) In addition to the two species in the genus _Iguana_, several other related genera in the same family have common names of the species including the word “iguana”.[[10]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-10) The species is a popular quarry for [pets](https://en.m.wikipedia.org/wiki/Pet), and non-native animals have been widely [introduced](https://en.m.wikipedia.org/wiki/Introduced_species) beyond its native area, into [Ishigaki Island](https://en.m.wikipedia.org/wiki/Ishigaki_Island), the [Florida Peninsula](https://en.m.wikipedia.org/wiki/Florida_Peninsula), [Hawaii](https://en.m.wikipedia.org/wiki/Hawaii), [Singapore](https://en.m.wikipedia.org/wiki/Singapore), [Thailand](https://en.m.wikipedia.org/wiki/Thailand), [Taiwan](https://en.m.wikipedia.org/wiki/Taiwan), and including numerous islands with native _Iguana_ populations in the [Lesser Antilles](https://en.m.wikipedia.org/wiki/Lesser_Antilles).[[8]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Iguana_iguana-8)[[11]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-van_den_BurgGoetzBrannon2023-11) Iguanas are large [lizards](https://en.m.wikipedia.org/wiki/Lizard) that can range from 1.2 to 2.0 m (4 to 6.5 ft) in length, including their tails. They possess a [dewlap](https://en.m.wikipedia.org/wiki/Dewlap) and a row of elongated scales running from the midline of their [necks](https://en.m.wikipedia.org/wiki/Neck) down to their [tails](https://en.m.wikipedia.org/wiki/Tail). Iguanas have varying types of scales covering different areas of their body; for example, some large, round [tuberculate scales](https://en.m.wikipedia.org/wiki/Reptile_scale) are scattered around the lateral region of the neck among smaller, overlapping scales.[[12]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Chang-Wu-etal-2009-12) The scales on the [dorsal](https://en.m.wikipedia.org/wiki/Anatomical_terms_of_location#Dorsal_and_ventral) trunk of their bodies are also thicker and more tightly packed than those on the [ventral](https://en.m.wikipedia.org/wiki/Ventral) sides.[[12]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Chang-Wu-etal-2009-12) These scales may be a variety of colors and are not always visible from close distances. They have a large, round scale on their cheeks known as a subtympanic shield.[[13]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Lazell-13) Iguanas have keen vision and can see shapes, shadows, colors, and movement at long distances. Their visual acuity enables them to navigate through crowded forests and to locate food. They employ visual signals to communicate with other members of the same species.[[13]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Lazell-13) The [tympanum](https://en.m.wikipedia.org/wiki/Tympanum_(zoology)), the iguana’s [eardrum](https://en.m.wikipedia.org/wiki/Eardrum), is located above the subtympanic shield (or “ear shield”) behind each eye (though the [Lesser Antillean iguana](https://en.m.wikipedia.org/wiki/Lesser_Antillean_iguana) lacks this shield). Iguanas are often hard to spot, as they tend to blend into their surroundings, and their coloration enables them to hide from larger predators.[[13]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Lazell-13) Like most [reptiles](https://en.m.wikipedia.org/wiki/Reptile), an iguana has a three-chambered [heart](https://en.m.wikipedia.org/wiki/Heart) with two atria, one ventricle, and two aortae with a [systemic circulation](https://en.m.wikipedia.org/wiki/Systemic_circulation).[[14]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-dabvp2561-14) The muscles of an iguana are very light in color due to the high proportion of [fast-twitch, glycolytic muscle fibers](https://en.m.wikipedia.org/wiki/Fast_twitch_muscle) (type A). These A fibers are not very vascularized and are low in [myoglobin](https://en.m.wikipedia.org/wiki/Myoglobin), giving them their pale look. This high density of A fibers allows iguanas to move very quickly for a short period of time, which facilitates short bursts of movement, but is inefficient for long duration movement, since cellular respiration in A fibers is [anaerobic](https://en.m.wikipedia.org/wiki/Anaerobic_respiration). ### Parietal eye [edit](https://en.m.wikipedia.org/w/index.php?title=Iguana&action=edit§ion=2) Several species of lizards, including the iguanas, have a pale scale towards the back of their heads marking the [parietal eye](https://en.m.wikipedia.org/wiki/Parietal_eye). This organ is sensitive to changes in illumination and sends signals to the [pineal gland](https://en.m.wikipedia.org/wiki/Pineal_gland) noting the change between day and night. A photopigment commonly found in the [lamprey](https://en.m.wikipedia.org/wiki/Lamprey), known as parapinopsin, is also found in the iguana, and is sensitive to [ultraviolet light](https://en.m.wikipedia.org/wiki/Ultraviolet_light) and aids in the signaling between day and night.[[15]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-wada4265-15) ### Skull morphology and diet Iguanas have developed an [herbivorous](https://en.m.wikipedia.org/wiki/Herbivorous) lifestyle, foraging exclusively on vegetation and foliage.[[16]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Lichtenbelt-1993-16) To acquire, process, and digest plant matter, herbivorous lizards must have a higher bite force relative to their size in comparison to [carnivorous](https://en.m.wikipedia.org/wiki/Carnivorous) or [omnivorous](https://en.m.wikipedia.org/wiki/Omnivorous) reptiles. The skull of the iguana has undergone modifications resulting in a strong bite force and efficient processing of [vegetation](https://en.m.wikipedia.org/wiki/Vegetation), according to one study.[[17]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Metzger-Herrel-2005-17) To accomplish this [biomechanically](https://en.m.wikipedia.org/wiki/Biomechanically), herbivorous lizards have taller and wider skulls, shorter snouts, and larger bodies relative to carnivorous and omnivorous reptiles.[[17]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Metzger-Herrel-2005-17) Increasing the strength of the skull allows for increased muscle presence and increases the ability of the skull to withstand stronger forces.[[18]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-herrel2461-18) Furthermore, the teeth of the iguana are [acrodontal](https://en.m.wikipedia.org/wiki/Acrodont), meaning that their teeth sit on top of the surface of the jaw bone[[19]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Kuss-2017-04-28-19) and project upwards. The teeth themselves are small and serrated - designed to grasp and shear food.[[20]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-banzato2631-20) ### Reproduction [edit](https://en.m.wikipedia.org/w/index.php?title=Iguana&action=edit§ion=4) Male iguanas, like other male examples of [Squamata](https://en.m.wikipedia.org/wiki/Squamata), have two [hemipenes](https://en.m.wikipedia.org/wiki/Hemipenis). During copulation, one hemipenis is inserted into the female’s [cloacal vent](https://en.m.wikipedia.org/wiki/Cloaca).[[21]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Flank2007-21) A female can [store sperm](https://en.m.wikipedia.org/wiki/Female_sperm_storage) from previous mates for several years to continue to fertilize her eggs in case she finds no male within her territory when she is ready to lay again.[[22]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-22)[[23]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-23)[[24]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-24) The number of eggs (a clutch) that a female can lay is strongly dependent of her body size and impacted by climatic and environmental conditions. Clutch size within _Iguana iguana_ has been recorded up to 71 eggs, whilst maximum clutch size for _Iguana delicatissima_ is 30, with the only reported hybrid female between both species had 35 eggs.[[25]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-t55-25) ### Mating/courtship [edit](https://en.m.wikipedia.org/w/index.php?title=Iguana&action=edit§ion=5) Iguanas tend to follow a promiscuous or [polygynandrous](https://en.m.wikipedia.org/wiki/Polygynandrous) mating style during the dry season. Mating during the dry season ensures that their offspring will hatch during the wet or rainy season when food will be more plentiful. Females control large territories, where they make several nests. Males compete for the females in an area and mark their won territory with a [pheromone](https://en.m.wikipedia.org/wiki/Pheromone) secreted from the [femoral pores](https://en.m.wikipedia.org/wiki/Femoral_pore) on the dorsal side of their hind limbs. Male behavior during sexual competition involves head bobbing, extending and retracting their [dewlap](https://en.m.wikipedia.org/wiki/Dewlap), nuzzling and biting the necks of females, and on occasion, changing color. Once a female chooses a male, he straddles the female and holds her in place by biting onto her shoulder, which sometimes leaves scars on females. After copulation, eggs are laid within a nest underground (at depths up to 1.65 m (5.5 ft) for the [Lesser Antillean iguana](https://en.m.wikipedia.org/wiki/Lesser_Antillean_iguana)) from which the hatchlings emerge after \>85 days of incubation. This low level of parental intervention with their offspring makes iguanas an example of [r-strategy](https://en.m.wikipedia.org/wiki/R-strategy) reproduction. ## Phylogeny [edit](https://en.m.wikipedia.org/w/index.php?title=Iguana&action=edit§ion=6) A [phylogeny](https://en.m.wikipedia.org/wiki/Phylogenetic_tree) based on nuclear protein-coding genes, reviewed by Vidal and Hedges (2009), suggested that the [subclade](https://en.m.wikipedia.org/wiki/Subclade) [Iguania](https://en.m.wikipedia.org/wiki/Iguanomorpha) is in a group with [snakes](https://en.m.wikipedia.org/wiki/Snake) and [anguimorphs](https://en.m.wikipedia.org/wiki/Anguimorpha) (lizards). These groups share an oral gland capable of secreting toxins (a derived trait).[[26]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Vidal-Hedges-2009-26) The phylogeny based on whole [mitochondrial genomes](https://en.m.wikipedia.org/wiki/Mitochondrial_DNA), though, as proposed by Rest et al. (2003), places the [green iguana](https://en.m.wikipedia.org/wiki/Green_iguana) as the closest relative of the [mole skink](https://en.m.wikipedia.org/wiki/Plestiodon_egregius) (_Plestiodon egregius_).[[27]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-molecular1326-27) [Lepidosaurs](https://en.m.wikipedia.org/wiki/Lepidosauria) are reptiles with overlapping scales, and within this group both iguanians and [tuataras](https://en.m.wikipedia.org/wiki/Tuatara) (_Sphenodon_) project their tongues to seize prey items instead of using their jaws, which is called tongue [prehension](https://en.m.wikipedia.org/wiki/Prehensility). Iguanians are the only lineage within the [Squamata](https://en.m.wikipedia.org/wiki/Squamata) that display this trait, meaning that it was gained independently in both iguanians and tuataras.[[26]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Vidal-Hedges-2009-26) Iguanians are also the only squamates that primarily use their sight to identify and track prey rather than chemoreception or scent, and employ an [ambush technique](https://en.m.wikipedia.org/wiki/Ambush_predator) of catching prey instead of active searching.[[26]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Vidal-Hedges-2009-26) A study by Breuil _et al._ (2020) found the taxonomy of the genus _Iguana_ as follows, with _I. delicatissima_ being the most [basal](https://en.m.wikipedia.org/wiki/Basal_(phylogenetics)) member of the group.[[7]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Breuil2020-7) The species are classified as subspecies based on the ReptileDatabase definitions. _[Sauromalus](https://en.m.wikipedia.org/wiki/Sauromalus)_ _Iguana_ _[I. delicatissima](https://en.m.wikipedia.org/wiki/Iguana_delicatissima)_ * * * _[I. iguana](https://en.m.wikipedia.org/wiki/Iguana_iguana)_ “_[I. i. rhinolopha](https://en.m.wikipedia.org/wiki/Iguana_iguana)_” _[I. i. insularis](https://en.m.wikipedia.org/w/index.php?title=Grenadines_horned_iguana&action=edit&redlink=1)_ * * * * * * _[I. i. sanctaluciae](https://en.m.wikipedia.org/w/index.php?title=Saint_Lucia_horned_iguana&action=edit&redlink=1)_ _[I. i. melanoderma](https://en.m.wikipedia.org/wiki/Iguana_melanoderma)_ * * * _[I. i. iguana](https://en.m.wikipedia.org/wiki/Iguana_iguana)_ The Reptile Database synonymizes _I. rhinolopha_ with _I. iguana_, only considering it a distinctive population, and recognizes _I. insularis_ and _I. melanoderma_ as [subspecies](https://en.m.wikipedia.org/wiki/Subspecies) of _I. iguana_. Four subspecies of green iguana are recognized under this treatment: _I. i. insularis_ ([Saint Vincent & the Grenadines](https://en.m.wikipedia.org/wiki/Saint_Vincent_and_the_Grenadines) and [Grenada](https://en.m.wikipedia.org/wiki/Grenada)), _I. i. sanctaluciae_ ([Saint Lucia](https://en.m.wikipedia.org/wiki/Saint_Lucia)), _I. i. melanoderma_ (parts of the northern Lesser Antilles, and potentially coastal [Venezuela](https://en.m.wikipedia.org/wiki/Venezuela), the [Virgin Islands](https://en.m.wikipedia.org/wiki/Virgin_Islands), and [Puerto Rico](https://en.m.wikipedia.org/wiki/Puerto_Rico)), and _I. i. iguana_ (mainland South America). The Central American iguana (_I. rhinolopha_ or _I. i. rhinolopha_ ), sometimes considered a distinct species, is largely considered synonymous with _I. iguana_ , as the presence of horns does not necessarily indicate a new species or subspecies. The two described subspecies of _I. insularis_ (the Saint Lucia horned iguana, _I. i. sanctaluciae_ , and the Grenadines horned iguana, _I. i. insularis_ ) were originally described as subspecies of _I. iguana_ , although they are genetically very similar and may not be separate subspecies from one another.[[29]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-29) Recent studies have recovered _I. rhinolopha_ and _I. insularis_ as distinct species based on genetics, but the Reptile Database disagrees with these conclusions, and classifies _I. rhinolopha_ as synonymous with _I. iguana_ , and _I. insularis_ as a subspecies of _I. iguana_ .[[30]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Stephen-Reynoso-etal-2013-30) The [Curaçao](https://en.m.wikipedia.org/wiki/Cura%C3%A7ao) population of green iguanas shows major genetic divergence and may also represent an as-of-yet [undescribed species](https://en.m.wikipedia.org/wiki/Undescribed_taxon) or subspecies.[[7]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-Breuil2020-7)[[31]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-31) ## Ecology [edit](https://en.m.wikipedia.org/w/index.php?title=Iguana&action=edit§ion=10) As large herbivores, iguanas are important members of the ecosystems they live in, especially on islands were often they are the largest native terrestrial species. Given their life history characteristics their impact on other species is high. By eating leaves and flowers they promote plant growth and flowering, and by eating fruits and seeds they aid the dispersal of these seeds and in that process can also aid for example seed germination. The large number of eggs that female iguanas lay provides high amounts of protein for predators that either target the eggs while these are incubating, or that feed on baby iguanas once they emerge. Also, the nests that female iguanas dig (including the tunnels) create complex underground systems with looser soil that other species can utilize; a recent study found that females of the [Lesser Antillean iguana](https://en.m.wikipedia.org/wiki/Lesser_Antillean_iguana) can lay their clutches at a depth of 1.65 m (5.5 ft) underground.[[34]](https://en.m.wikipedia.org/wiki/Iguana#cite_note-t559-34)