The
Green Iguana or
Common Iguana (
Iguana iguana) is a large, arboreal herbivorous
speciesIn biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of
lizardLizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
IguanaIguana is a herbivorous genus of lizard native to tropical areas of Central America and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena...
native to
CentralCentral America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and
South AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. The green iguana ranges over a large geographic area, from southern
BrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and
ParaguayParaguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
to as far north as
MexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the
CaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
Islands; and in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
as
feralA feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
populations in
South FloridaThe South Florida metropolitan area, also known as the Miami metropolitan area, and designated the Miami–Fort Lauderdale–Pompano Beach, FL Metropolitan Statistical Area by the U.S...
(including the
Florida KeysThe Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
),
HawaiiHawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, and the
Rio Grande ValleyThe Rio Grande Valley or the Lower Rio Grande Valley, informally called The Valley, is an area located in the southernmost tip of South Texas...
of
TexasTexas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
.
A herbivore, it has adapted significantly with regard to locomotion and
osmoregulationOsmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
as a result of its diet. It grows to 1.5 metres (4.9 ft) in length from head to tail, although a few specimens have grown more than 2 metres (6.6 ft) with bodyweights upward of 20 pounds (9.1 kg).
Commonly found in captivity as a
petA pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
due to its calm disposition and bright colors, it can be demanding to care for properly. Space requirements and the need for special lighting and heat can prove challenging to an amateur hobbyist.
Taxonomy and etymology
The species was first officially described by Swedish
botanistBotany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
Carl Linnaeus in 1758. In the two centuries since then, no less than 17 species and
subspeciesSubspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
have been identified with all but one species (
Iguana delicatissimaThe Lesser Antillean Iguana is a large arboreal lizard endemic to the Lesser Antilles. It is one of two species of lizard of the genus Iguana and is in severe decline due to habitat destruction, feral predators, hunting, and hybridization with its sister species the Green iguana...
) being found to be invalid.
Using nuclear and
mitochondrialIn cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...
DNA-sequence data to explore the
phylogenicIn biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
history of the green iguana, scientists from Utah Valley State College studied animals collected from 17 different countries. The
topologyTopology is a major area of mathematics concerned with properties that are preserved under continuous deformations of objects, such as deformations that involve stretching, but no tearing or gluing...
of phylogeny indicated that the species originated in South America and eventually radiated through Central America and the Caribbean. The study revealed no unique
mitochondrial DNAMitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
haplotypes for subspecific status but did indicate the deep lineage divergence between Central and South American populations.
The word
iguana is derived from a Spanish form of the
TaínoThe Taínos were pre-Columbian inhabitants of the Bahamas, Greater Antilles, and the northern Lesser Antilles. It is thought that the seafaring Taínos are relatives of the Arawak people of South America...
name for the species:
iwana. In some Spanish speaking countries, males of the species are referred to as
gorrobo or
ministro and juveniles are called
iguanita or
gorrobito.
Distribution and habitat
The native range of the Green Iguana extends from southern Mexico to central Brazil, Paraguay, and
BoliviaBolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
and the
CaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
; specifically
GrenadaGrenada is an island country and Commonwealth Realm consisting of the island of Grenada and six smaller islands at the southern end of the Grenadines in the southeastern Caribbean Sea...
,
CuraçaoCuraçao is an island in the southern Caribbean Sea, off the Venezuelan coast. The Country of Curaçao , which includes the main island plus the small, uninhabited island of Klein Curaçao , is a constituent country of the Kingdom of the Netherlands...
,
Trinidad and TobagoTrinidad and Tobago officially the Republic of Trinidad and Tobago is an archipelagic state in the southern Caribbean, lying just off the coast of northeastern Venezuela and south of Grenada in the Lesser Antilles...
,
St. LuciaSaint Lucia is an island country in the eastern Caribbean Sea on the boundary with the Atlantic Ocean. Part of the Lesser Antilles, it is located north/northeast of the island of Saint Vincent, northwest of Barbados and south of Martinique. It covers a land area of 620 km2 and has an...
,
St. VincentSaint Vincent is a volcanic island in the Caribbean. It is the largest island of the chain called Saint Vincent and the Grenadines. It is located in the Caribbean Sea, between Saint Lucia and Grenada. It is composed of partially submerged volcanic mountains...
, and
ÚtilaUtila is the third largest of Honduras' Bay Islands, after Roatán and Guanaja, in a region that marks the south end of the Mesoamerican Barrier Reef System, the second-largest in the world...
. They have been introduced to
Grand CaymanGrand Cayman is the largest of the three Cayman Islands and the location of the nation's capital, George Town. In relation to the other two Cayman Islands, it is approximately 75 miles southwest of Little Cayman and 90 miles southwest of Cayman Brac.-Geography:Grand Cayman encompasses 76% of...
,
Puerto RicoPuerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
,
TexasTexas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, Florida, Hawaii, and the
United States Virgin IslandsThe Virgin Islands of the United States are a group of islands in the Caribbean that are an insular area of the United States. The islands are geographically part of the Virgin Islands archipelago and are located in the Leeward Islands of the Lesser Antilles.The U.S...
.
Green Iguanas are diurnal, arboreal, and are often found near water. Agile climbers,
Iguana iguana can fall up to 50 feet (15.2 m) 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, an iguana remains submerged, letting its four legs hang limply against its side. They propel through the water with powerful tail strokes.
Because of the Green Iguana's popularity in the pet trade and as a food source in
Latin AmericaLatin America is a region of the Americas where Romance languages – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...
, they are listed on the CITES Appendix II, which means that while they are not an
endangered speciesAn endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
, "their trade must be controlled so as to not harm the species in the future".
Anatomy and morphology
Despite their name, Green Iguanas can come in different colors. In southern countries of their range, such as
PeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, green iguanas appear bluish in color with bold black markings. On islands such as
Bonaire,
CuraçaoCuraçao is an island in the southern Caribbean Sea, off the Venezuelan coast. The Country of Curaçao , which includes the main island plus the small, uninhabited island of Klein Curaçao , is a constituent country of the Kingdom of the Netherlands...
,
ArubaAruba is a 33 km-long island of the Lesser Antilles in the southern Caribbean Sea, located 27 km north of the coast of Venezuela and 130 km east of Guajira Peninsula...
, and
GrenadaGrenada is an island country and Commonwealth Realm consisting of the island of Grenada and six smaller islands at the southern end of the Grenadines in the southeastern Caribbean Sea...
, a Green Iguana's color may range from green to lavender, black, and even pink. 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 SalvadorEl Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
are often bright blue as babies, however they lose this color as they get older.
Iguana iguana possess a row of spines along their backs and along their tails which helps to protect them from predators. Their whip-like tails can be used to deliver painful strikes and like many other lizards, when grabbed by the tail, the iguana can allow it to break, so it can escape and eventually regenerate a new one. In addition, iguanas have well developed
dewlapA dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...
s which helps regulate their body temperature. This dewlap is used in courtships and territorial displays.
Green Iguanas have excellent vision, enabling them to detect shapes and motions at long distances. As Green Iguanas have only a few
Rod cellRod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
s, they have poor vision in low-light conditions. At the same time, they have cells called “double
Cone cellCone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s” that give them sharp color vision and enable them to see
ultravioletUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
wavelengths. This ability is highly useful when basking so the animal can ensure that it absorbs enough sunlight in the forms of UVA and UVB to produce
Vitamin DVitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
.
Green Iguanas have a white photosensory organ on the top of their heads called the
parietal eyeA parietal eye, also known as a parietal organ or third-eye or pineal eye, is a part of the epithalamus present in some animal species...
(also called third eye, pineal eye or
pineal glandThe pineal gland is a small endocrine gland in the vertebrate brain. It produces the serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal functions...
), in contrast to most other lizards, which have lost it. This "eye" does not function the same way as a normal eye does, as it has only a rudimentary retina and lens and cannot form images. It is, however, sensitive to changes in light and dark and can detect movement. This helps the iguana when being stalked by predators from above.
Green Iguanas have very sharp teeth that are capable of shredding leaves and even human skin. These teeth are shaped like a leaf, broad and flat, with serrations on the edge. The similarity of these teeth to those of one of the first dinosaurs discovered led to the dinosaur being named
IguanodonIguanodon is a genus of ornithopod dinosaur that lived roughly halfway between the first of the swift bipedal hypsilophodontids and the ornithopods' culmination in the duck-billed dinosaurs...
, meaning "iguana-tooth", and the incorrect assumption that it had resembled a gigantic iguana. The teeth are situated on the inner sides of the jawbones which is why they are hard to see in smaller specimens.
Primarily herbivorous, Green Iguanas are presented with a special problem for
osmoregulationOsmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
; plant matter contains more
potassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and as it has less nutritional content per gram, more must be eaten to meet metabolic needs. As Green Iguanas are not capable of creating liquid urine more concentrated than their bodily fluids, like birds they excrete nitrogenous wastes as urate salts through a
salt glandThe salt gland is an organ for excreting excess salts. It is found in elasmobranchs, seabirds, and some reptiles. In sharks, salt glands are found in the rectum, but in birds and reptiles, they are found in or on the skull, in the area of the eyes, nostrils or mouth. In crocodiles, the salt is...
. As a result, Green iguanas have developed a lateral
nasalAnatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes through the pharynx, shared with the...
gland to supplement renal salt secretion by expelling excess potassium and sodium chloride.
Green Iguanas from
GuatemalaGuatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
and southern Mexico predominantly have small horns on their snouts between their eyes and their nostrils, whereas others do not. Naturalists once classified these iguanas as a separate
subspeciesSubspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
(
Iguana iguana rhinolopha); however, this classification has been found to be invalid based on mitochondrial DNA and iguanas with similar nose projections appear randomly in other populations and interbreed freely with those that do not share this trait.
The Green Iguana is a large lizard, typically growing to 1.5 metres (4.9 ft) in length from head to tail. Some specimens have been measured upwards of 2 metres (6.6 ft) with bodyweights greater than 20 pounds (9.1 kg).
Reproductive biology
Male Green Iguanas have highly developed
femoralFemoral can refer to:* Femoral artery* Femoral vein* Femur* Femoral triangle* Femoral nerve...
poresSweat glands, or sudoriferous glands, are small tubular structures of the skin that produce sweat. There are two kinds of sweat glands:...
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 dimorphicSexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
.
Green Iguanas are
oviparousOviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, reptiles, all birds, the monotremes, and most insects, some molluscs and arachnids....
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
PanamaPanama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, the Green iguana has been observed sharing nest sites with
American crocodileThe American crocodile is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas. Populations occur from the Atlantic and Pacific coasts of southern Mexico to South America as far as Peru and Venezuela. It also lives...
s and in
HondurasHonduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
with
Spectacled CaimanThe spectacled caiman , also known as the white caiman or common caiman, is a crocodilian reptile found in much of Central and South America. It lives in a range of lowland wetland and riverine habitat types and can tolerate salt water as well as fresh; due in part to this adaptability it is the...
s.
The hatchlings emerge from the nest after 10–15 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 which does this.
Behavior
When frightened by a
predatorIn ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
, Green Iguanas will attempt to flee, and if near a
body of waterA body of water or waterbody is any significant accumulation of water, usually covering the Earth or another planet. The term body of water most often refers to large accumulations of water, such as oceans, seas, and lakes, but it may also include smaller pools of water such as ponds, puddles or...
, they dive into it and swim away. If cornered by a threat, the Green Iguana will extend and display the
dewlapA dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...
under its neck, stiffen and puff up its body, hiss, and bob its head at the aggressor. If threat persists the
Iguana can lash with its tail, bite and use its claws in defense. The wounded are more inclined to fight than uninjured prey.
Green Iguanas use "head bobs" and dewlaps in a variety of ways in social interactions, such as greeting another iguana or to court a possible mate. The frequency and number of head bobs have particular meanings to other iguanas.
Green Iguanas are preyed upon by
hawkThe term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s and their fear of hawks is exploited as a ploy to catch them in the wild. The sound of a hawk's whistle or scream makes the iguana freeze and it becomes easier to capture.
Diet
Green Iguanas are primarily herbivores, feeding on leaves, flowers, fruit, and growing shoots of upwards of 100 different species of plant. In Panama one of the Green iguana's favorite foods is
wild plumSpondias mombin is a tree, a species of flowering plant in the family Anacardiaceae. It is native to the tropical Americas, including the West Indies. The tree has been naturalized in parts of Africa, India, Sri Lanka and Indonesia. It is rarely cultivated.The mature fruit has a leathery skin and a...
,
Spondias mombin.
Although they will consume a wide variety of foods if offered, Green Iguanas are naturally herbivorous and require a precise ratio of minerals (2 to 1
calciumCalcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
to
phosphorusPhosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
) in their diet. Juvenile iguanas often eat
fecesFeces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
from adults in order to acquire the essential
microfloraGut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
to digest their low-quality and hard to process vegetarian only diet.
There is some debate as to whether captive Green Iguanas should be fed animal protein. There is evidence of wild iguanas eating
grasshopperThe grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s and
tree snailTree snail is a common name that is applied to various kinds of tropical air-breathing land snails, pulmonate gastropod mollusks that have shells, and that live in trees, in other words, are exclusively arboreal in habitat....
s, usually as a byproduct of eating plant material. Wild adult Green Iguanas have been observed eating bird's eggs. Zoologists, such as Adam Britton, believe that such a diet containing protein is unhealthy for the animal's digestive system resulting in severe long-term health damage including kidney failure and leading to premature death. On the other side of the argument is that Green Iguanas at the
Miami SeaquariumThe Miami Seaquarium is a oceanarium located on the island of Virginia Key in Biscayne Bay, Miami-Dade County, Florida, United States and is located near downtown Miami. It is the longest operating oceanarium in the United States. In addition to the marine mammals, the Miami Seaquarium also...
in
Key BiscayneKey Biscayne is an island located in Miami-Dade County, Florida, United States, between the Atlantic Ocean and Biscayne Bay. It is the southernmost of the barrier islands along the Atlantic coast of Florida, and lies south of Miami Beach and southeast of Miami...
, Florida, have been observed eating dead fish and individuals kept in captivity have been known to eat mice without any ill effects. De Vosjoli writes that captive animals have been known to survive and thrive on eating nothing but whole rodent block, or monkey chow, and one instance of
Romaine lettuceRomaine or cos lettuce is a variety of lettuce which grows in a tall head of sturdy leaves with a firm rib down the center. Unlike most lettuces, it is tolerant of heat...
with vitamin and calcium supplements.
Captivity
The American pet trade has put a great demand on the Green Iguana; 800,000 iguanas were imported into the U.S. in 1995 alone, primarily originating from captive farming operations based in their native countries (Honduras, El Salvador, Colombia, and Panama). However, these animals are demanding to care for properly over their lifetime, and many die within a few years of acquisition.
Although, in captivity, Green Iguanas will eat meat if presented with it, excessive consumption of animal protein results in severe kidney problems and possible premature
deathDeath is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
. Misinformed pet owners tend to feed iguanas
iceberg lettuceLettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...
, which provides iguanas with water but has no other nutritional value. A captive Green Iguana's diet should consist of fresh leafy vegetables such as
mustard greensBrassica juncea, also known as mustard greens, Indian mustard, Chinese mustard, and leaf mustard, is a species of mustard plant. Subvarieties include southern giant curled mustard, which resembles a headless cabbage such as kale, but with a distinct horseradish-mustard flavor...
,
collard greensCollard greens are various loose-leafed cultivars of Brassica oleracea , the same species as cabbage and broccoli. The plant is grown for its large, dark-colored, edible leaves and as a garden ornamental, mainly in Brazil, Portugal, the southern United States, many parts of Africa, Montenegro,...
,
dandelionTaraxacum is a large genus of flowering plants in the family Asteraceae. They are native to Eurasia and North America, and two species, T. officinale and T. erythrospermum, are found as weeds worldwide. Both species are edible in their entirety...
, arugula, or
kaleKale is very high in beta carotene, vitamin K, vitamin C, lutein, zeaxanthin, and reasonably rich in calcium. Kale, as with broccoli and other brassicas, contains sulforaphane , a chemical with potent anti-cancer properties. Boiling decreases the level of sulforaphane; however, steaming,...
and access to fresh water.
Green Iguanas will thrive only in temperatures of 79 °F (26.1 °C) to 95 °F (35 °C) and must have appropriate sources of
UVBUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
and
UVAUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
lighting, or else their bodies cannot produce
vitamin DVitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
that promotes calcium absorption, which can result in a metabolic bone disease that can be fatal.
In some locales (
New York CityNew York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
and
HawaiiHawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
), iguanas are considered
exotic petAn exotic pet is a rare or unusual animal pet, or an animal kept as a pet which is not commonly thought of as a pet.The definition is an evolving one; some rodents, reptiles, and amphibians have become firmly enough established in the world of animal fancy to no longer be considered exotic...
s, and are prohibited from ownership. Due to the potential impact of an introduced species on Hawaii's ecosystem, the state has strict regulations regarding the import and possession of Green Iguanas; violators can spend three years in jail and be fined up to $200,000.
Invasive species
Caribbean
In the aftermath of two
CaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
hurricaneA tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
s in 1995, a group of fifteen Green Iguanas was found to be living on
AnguillaAnguilla is a British overseas territory and overseas territory of the European Union in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Saint Martin...
; an island where that species have never been recorded previously.
BiologistA biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
Ellen Censky, of the
Connecticut State Museum of Natural HistoryThe Connecticut State Museum of Natural History is located in Storrs, Connecticut and is part of the University of Connecticut.The small museum contains a variety of scientific and archaeological collections about the cultural history of southern New England...
, believes that the new iguanas had accidentally become caught on the trees and rafted two hundred miles across the ocean from
GuadeloupeGuadeloupe is an archipelago located in the Leeward Islands, in the Lesser Antilles, with a land area of 1,628 square kilometres and a population of 400,000. It is the first overseas region of France, consisting of a single overseas department. As with the other overseas departments, Guadeloupe...
, where Green iguanas are an indigenous species. By examining the weather patterns and ocean currents, Censky has shown that the iguanas had spent three weeks at sea before arriving on the island. This colony began breeding on the new island within two years of its arrival.
Fiji
The Green Iguana is present on some of the islands of
FijiFiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, were it is known as the American iguana. They pose a threat to the
native iguanasThe genus Brachylophus consists of three extant iguanid species native to the islands of Fiji and a giant extinct species from Tonga in the South Pacific. One of the extant species, B...
through the potential spread of disease and to humans by spreading
salmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
. They were initially brought to
QameaQamea is one of three islets lying to the east of Thurston Point on the island of Taveuni, Fiji, the others being Matagi and Laucala.-Geography:...
in 2000 by an American who wanted them to eat the numerous insects on the island. They are now present on the islands of
LaucalaLaucala is one of three small islands lying to the east of Thurston Point on the island of Taveuni in Fiji. The privately owned island is the site of the exclusive Laucala Resort....
,
MatagiMatagi , sometimes written Matangi, is an island of Fiji, one of three tiny volcanic islands grouped to the east of Thurston Point on the island of Taveuni, the others being Qamea and Laucala...
and
TaveuniTaveuni is the third-largest island in Fiji, after Vanua Levu and Viti Levu, with a total land area of 435 square kilometers . The cigar-shaped island, a massive shield volcano which rises from the floor of the Pacific Ocean, is situated 6.5 kilometers to the east of Vanua Levu, across the...
.
United States
The Green Iguana is established on
OahuOahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
and
MauiThe island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, Hawaii as a feral species (despite strict legislation banning the importation of any reptiles) and the Rio Grande Valley of Texas. As most reptiles carry
salmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
, 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"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in
South FloridaThe South Florida metropolitan area, also known as the Miami metropolitan area, and designated the Miami–Fort Lauderdale–Pompano Beach, FL Metropolitan Statistical Area by the U.S...
and is found along the gulf coast of
FloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
from
Key WestKey West is an island in the Straits of Florida on the North American continent at the southernmost tip of the Florida Keys. Key West is home to the southernmost point in the Continental United States; the island is about from Cuba....
to
Pinellas CountyPinellas County is a county located in the state of Florida. Its county seat is Clearwater, Florida, and its largest city is St. Petersburg. This county is contained entirely within the telephone area code 727, except for some sections of Oldsmar, which have the area code 813...
. The original small populations in the Florida Keys were animals that were stowaways on ships carrying fruit from South America. Over the years, other iguanas were introduced into the wild mostly originating through the pet trade. Some were escapees and some were intentionally released by their owners; these iguanas survived and then thrived in their new habitat. They commonly hide in the attics of houses and on beaches. They often destroy gardens and landscaping. They seem to be fond of eating a native endangered plant,
Cordia globosaCordia is a genus of flowering plants in the borage family, Boraginaceae. It contains about 300 species of shrubs and trees, which are found worldwide mostly in warmer regions. Many of the species are commonly called manjack, while bocote may refer to several Central American species in Spanish...
and feeding on
NickernutNickernuts or nickar nuts are smooth, shiny seeds from tropical leguminous shrubs, particularly Caesalpinia bonduc and C. major, both known by the common name warri tree. C. bonduc produces gray nickernuts, and C. major produces yellow...
(
CaesalpiniaCaesalpinia is a genus of flowering plants in the legume family, Fabaceae. Membership within the genus is controversial, with different publications including anywhere from 70 to 165 species, depending largely on the inclusion or exclusion of species alternately listed under genera such as...
) a primary food plant of the endangered
Miami Blue ButterflyThe Miami blue is a small butterfly that is native to coastal areas of southern Florida. Once very common throughout its range, it has become critically endangered, and may be the rarest insect in the United States...
(
Cyclargus thomasi bethunebakeri); additionally on
Marco IslandMarco Island is a city in Collier County, Florida, United States, located on an island by the same name in the Gulf of Mexico off the coast of Southwest Florida. It is a principal city of the Naples–Marco Island Metropolitan Statistical Area...
, Green Iguanas have been observed using the burrows of the
Florida Burrowing OwlThe Burrowing Owl is a tiny but long-legged owl found throughout open landscapes of North and South America. Burrowing Owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open dry area with low vegetation. They nest and roost in burrows, such as those excavated...
, a species of special concern, all of which can make them more of a serious threat to Florida's ecosystem than originally believed.
In January 2008, large numbers of feral iguanas in Florida dropped from the trees in which they lived, due to uncommonly cold nights causing them to go into brumation in which they lost their grips on the tree branches. Though no specific numbers were provided by local wildlife officials, local media described the phenomenon as a "frozen iguana shower" in which dozens "littered" local bike paths. Upon the return of daytime warmth many (but not all) of the iguanas "woke up" and resumed their normal activities. This occurred again in January 2010 after a prolonged cold front once again hit southern Florida.
Cultural references
The
Moche'The Moche civilization flourished in northern Peru from about 100 AD to 800 AD, during the Regional Development Epoch. While this issue is the subject of some debate, many scholars contend that the Moche were not politically organized as a monolithic empire or state...
people of ancient
PeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
worshipped animals and often depicted Green Iguanas in their art. The Green iguana and its relative the Black iguana
(Ctenosaura similisThe Black Spiny-tailed Iguana, Black Iguana, or Black Ctenosaur is a lizard native to Mexico and Central America that has been introduced to the United States in the state of Florida...
) have been used as a
food sourceIguana meat has until recently been important in the culinary traditions of Mexico; particularly in the states of Jalisco, Michoacán and Colima. But they are still very important...
in Central and South America for the past 7000 years. It is possible that some of the populations in the
CaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
were translocated there from the mainland by various tribes as a food source. In Central and South America, Green Iguanas are still used as a source of meat and are often referred to as
gallina de palo, "bamboo chicken" or "chicken of the tree," because they are said to
taste like chicken"Tastes like chicken" is a common declaration used when trying to describe the flavor of a food a listener has never tasted. The expression has been used so often that it has become somewhat of a cliché...
.
External links