The iguana is a fantastic looking creature. With a ridge along the back and tail, lots of skin textures and a scaly “beard”. The animal looks like a small dragon. And although it is called the green iguana, it does not always have greenish skin tones. Coloration can be blue-green, bright green, reddish, gray and yellow to pale pink and lavender. In some places, iguanas are even blue when young, but gradually change color as they age.
Species origin and description
This species was first officially described by the Swedish botanist Carl Linnaeus in 1758. Within two centuries since then, many subspecies have been identified, but later, after genetic studies, they were classified as simple regional variants of the same species, except for the Caribbean iguana.
Using nuclear and mitochondrial DNA sequence data to study the phylogenetic history of the iguana, the scientists studied animals collected from 17 different countries. The topology of the phylogeny showed that this species originated in South America and eventually moved through Central America and the Caribbean. The study did not identify unique mitochondrial DNA haplotypes for subspecies status, but indicated a deep lineage divergence between Central and South American populations.
There are two subspecies of the common iguana:
- iguana iguana iguana is distributed in the Lesser Antilles and South America;
- iguana iguana rhinolopha is native primarily to Central America.
Both taxa can be fairly safely distinguished by the two or three small “horns” on the muzzle present in the rhinolopha iguana. The word “iguana” comes from the Spanish form of the name in the language of the Taíno people, who lived in the Caribbean before the arrival of the conquistadors and sounded like “iwana”. Over time, the Spanish version of the name passed into the scientific name of this species. In some Spanish-speaking countries, males of this species are called gorrobo or miniro, and juveniles are called iguanita or gorrobito.
Appearance and features
After hatching, the length of iguanas varies from 16 to 25 cm. Most mature iguanas weigh between 4 and 6 kg, but some can reach 8 kg with proper nutrition. These large lizards are about 2 m long. Despite the fact that these animals are called green iguanas, their coloration is different. Adults become more uniform in color with age, while juveniles may appear more mottled or striped between green and brown. An individual's color can also vary depending on its mood, temperature, health, or social status. This color change may help these animals with thermoregulation.
In the morning, when body temperature is low, the skin color will be darker, helping the lizard absorb heat from sunlight. However, when the hot midday sun shines on them, these animals become lighter or paler, helping to reflect the sun's rays and minimizing the heat they absorb. Active dominant iguanas are usually darker in color than lower ranked iguanas living in the same environment. Most of the color variations seen in this species appear in males and can be partly attributed to sex steroids.
Fun Fact: Six to eight weeks before and during courtship, males can turn a bright orange or golden hue, although the coloration is still associated with dominance status. Mature females retain their green color for the most part.
Other distinguishing features of this species include a pouch under the throat, a dorsal ridge consisting of skin spikes running from the middle of the neck to the base of the tail, and a long, tapering, flat tail. Milk thistle is more developed in adult males than in females. The extensions of the hyoid bones stiffen and support the cutting edge of this structure, which is used in territorial defense or when the animal is frightened. This fleshy structure also serves to absorb and dissipate heat as it expands.
The laterally located eyes are protected mainly by a fixed eyelid and a freely movable lower eyelid. On the dorsal midline of the skull behind the eyes is the parietal ocellus. This sense organ, although not a real “eye”, serves as a measure of solar energy and contributes to the maturation of the genitals, thyroid and endocrine glands. The visual effect of this “eye” is mostly limited to detecting predatory shadows from above.
Where does the iguana live?
The common iguana is found throughout Central and South America, from Sinaloa and Veracruz, Mexico, south to Paraguay and southeastern Brazil. This large lizard is also found on many islands throughout the Caribbean and coastal eastern Pacific and has been introduced to southern Florida and Hawaii. In addition, green iguanas colonized the island of Anguilla in 1995 after being washed ashore by a hurricane.
Common iguanas live in the rainforests of:
- northern Mexico;
- Central America;
- in the Caribbean;
- in southern Brazil.
Although the species is not native to Martinique, a small wild colony of released or escaped green iguanas lives in the historic Fort St. Louis. Iguanas — These are tree lizards that live high in the crowns of trees. Juveniles establish areas lower in the canopies while older mature iguanas reside above. This habit of living in trees allows them to bask in the sun, rarely descending, except when the females dig holes to lay their eggs.
Although the animal prefers a woody (forest) environment, it can adapt well to more open areas. Regardless of where they live, iguanas prefer to have water nearby, as they are excellent swimmers and dive underwater to avoid predators. In South and Central America, where the common iguana is native, it is an endangered species in some countries because people hunt and eat this “chicken in the trees”.
What does the iguana eat? ?
Iguanas are primarily herbivores. Green leafy plants or ripe fruits are the preferred food. But sometimes they eat small amounts of meat or invertebrates. Iguanas use their tongues to manipulate food and bite into small pieces to swallow with little to no chewing. Food is mixed with enzymes in the stomach and then passed into the small intestine, where it is mixed with pancreatic enzymes and bile. Most digestion takes place in the colon, where the microflora breaks down cellulose. The microflora is necessary for the digestion of the hindguts of this species of indigestible food.
Fun Fact: Iguana chicks tend to feed on adult feces, which may be an adaptation for acquiring much-needed microflora. This microflora breaks down food and makes it available for absorption.
In the first three years, iguanas need a lot of dietary protein to grow fast enough. During this period, young iguanas may consume insects and spiders. Elderly iguanas that have reached near maximum growth consume a low-phosphorus, high-calcium, leafy diet for their needs.
Iguanas are ectothermic animals. Their body temperature depends on the ambient temperature. Low temperatures suppress the iguana's appetite and reduce the activity of digestive enzymes. Active feeding usually occurs when the ambient temperature is 25-35°C. Warm up — an important aid to digestion. Iguanas may stop eating before or during skin change. Females may refuse to eat in the later stages of egg development. Individuals that are overly stressed or in new environments may also refuse to eat.
Now you know what to feed an iguana. Let's see how the green lizard lives.
Character and lifestyle features
In the wild, most disputes between iguanas occur over places where the body can be heated. These herbivorous lizards usually have enough food. Bathing is important for raising body temperature and improving digestion. During the breeding season, males display territorial claims through head bouncing and color changes. They bite each other. Injuries are rare in the wild as males have plenty of room to retreat when threatened. However, in captivity, where space is limited, injuries are more common.
Females may also exhibit some of these behavioral skills when nesting sites are limited. Common iguanas can travel considerable distances on several occasions. Females migrate to the same nesting site for several consecutive years and then return to their home territory after laying eggs. Cubs can also move long distances.
When frightened, an iguana will usually freeze or hide. Like many other lizards, iguanas can shed part of their tail. This gives them a chance to escape before the predator figures out what's going on. A new tail will sprout and grow in a year, but not to the length it was before. Near the runs, iguanas jump into the water from overhanging branches and then swim away from the threat. Animals prefer tall and dense vegetation with plenty of moisture, sun and shade.
Social structure and reproduction
Most common iguanas reach sexual maturity at 3-4 years of age, although maturity may be reached earlier. They breed during the dry season, resulting in offspring during the rainy season when food is more available. Courtship takes place in a defined area where more than one female may be present. Conflicts between males are not uncommon. Dominant males mark rocks, branches, and females with a waxy pheromone secreted from their thigh pores.
During mating, the male climbs onto the female's back. To keep the female, he grabs the skin of her shoulder with his teeth, even causing injuries. The male then connects his cloacal opening to the female and inserts one of his hemipenes into her cloaca. Copulation may take several minutes. Females can store sperm for several years, allowing them to fertilize eggs much later. Approximately 65 days after mating, the female to oviposition. The size and number of eggs varies depending on her size, nutrition and age. The eggs are about 15.4 mm in diameter and 35 to 40 mm long.
Over a three-day period, an average of 10 to 30 white or pale cream colored leathery eggs are placed in the nest. Nests are located at a depth of 45 cm to a meter and may lie together with the eggs of other females if the nesting area is limited. After laying eggs, females may return to the nest several times, but do not stay to guard it. Incubation lasts from 91 to 120 days. The temperature should be between 29 and 32°C. Chicks open the egg using a special tooth that falls out shortly after hatching.
Fun fact: After hatching, young iguanas look similar to adults in color and shape. They resemble adult females rather than males and lack dorsal spines. With age, these animals do not have major morphological changes, except that they grow.
However, the diet of an animal is directly related to age. Young iguanas have a higher protein requirement, more insects and eggs than mature iguanas. The offspring remain in family groups during the first year of life. The male iguanas in these groups often use their own bodies to defend themselves and protect the females from predators, and this seems to be the only reptile species that does so.
Iguanas' natural enemies
One of the best ways for iguanas to avoid predators is their coloration. Because they are extremely similar to their habitat. Having noticed the danger, the animal remains motionless and unnoticed. Young iguanas can be found in small groups and use a “selfish herd” or “the more eyes the better” strategy to avoid predators. Iguanas prefer to bask on tree branches that hang over the water, so when threatened by a predator, they dive into the water and swim away quickly.
In addition to these predation avoidance strategies, green iguanas are able to shed most of their tail, thus distracting predators and allowing them to escape. Hawks and other large birds are potential predators of juvenile iguanas. Humans are one of the main predators of common iguanas. They eat both iguanas and their eggs. In addition, people use these reptiles to bait crocodiles and catch them for the pet trade. Like many other animals, green iguanas suffer from habitat destruction.
Fun fact: In some countries, the iguana has culinary significance. The meat is harvested from both game animals and farm animals. Their meat is eaten and is called “green chicken” because the type of meat resembles chicken. A well-known iguana dish is Sopa de Garrobo.
The green iguana is one of the most popular terrarium animals and is currently farmed in South America for this purpose. But many buyers are unaware that the small iguana they usually sell will be up to 2m long.
Population and Species Status
Although some populations have been affected by poaching and capture for the pet trade, green iguanas are not considered endangered. The common iguana is listed on CITES Appendix II. This means that trade in this species needs to be regulated. The IUCN lists the iguana as a species of Least Concern. That being said, mention of habitat loss due to urbanization is a possible problem for green iguana populations in the future.
Fun fact: In addition to dispersing seeds, iguanas serve as a food source for larger animals. Like other amphibians and reptiles, iguanas can be indicators of environmental change. By observing the reactions of reptiles, people can be alerted to possible environmental problems.
Historically, green iguana meat and eggs have been eaten as a source of protein and are valued for their supposed medicinal and aphrodisiac properties. The iguana has been raised in captivity as a food source in an attempt to encourage more sustainable land use in Panama and Costa Rica. Conservation methods that have been used to conserve and strengthen iguana populations include captive breeding programs, a practice in which juveniles, either wild-caught or captive-bred, are released in the right area.