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Iguanas
Iguaninae
INDEX
WHAT ARE IGUANAS?
DIET
IGUANA FEATURES
WEST INDIAN IGUANAS AND CONSERVATION
BAHAMIAN IGUANAS AND CONSERVATION
IGUANAS OF ARDASTRA
WHAT ARE IGUANAS?
The word “Iguana” comes from the spanish version of the Carib word, Iwana. This is the name given to a family of lizards that are found throughout the Americas, West indies, Galapagos Islands and the Figi Islands. They can be found in deserts, forests, rocky areas and coastal areas.
Have a look at the Iguanas of the World (pdf)
DIET
Most lizards are carnivores, eating insects and other animals. However, iguanas only eat meat when they are young and still growing. When they reach adulthood, they
become almost strictly
vegetarian,
eating leaves, fruits and flowers, including some that are toxic to humans. The iguanas rarely have to drink in the wild as they get their water they need from the succulent plants that they eat.
IGUANA FEATURES
All iguanas have strong jaws, long tails and strong legs with long, sharp claws, and the iguana family includes about 30 different species.
Great defense
Iguana tails are very hard and long. They use it as a whip to defend themselves. Iguanas, like most lizards, can drop their tails as a defense tactic to escape from predators. The skin, muscles, blood supply, nerves and bone can break at any point along the tail. Therefore, if a predator captures the tail, the iguana can run away leaving the tail still wiggling in the attacker’s mouth. The tail will eventually grow back, but it will not grow quite as long or be the same color as the old tail.
Eye see the light!
Most animals have 2 eyes, but an iguana actually has 3 eyes! Their third eye is called the Parietal eye and it is found on the top of the iguana’s head. This eye does not see detail and color like our eyes, but it does see light (photoreceptor). The iguana uses this eye to recognise if it is sitting in sunlight or in the shade. This eye can also detect movement from above, so it could be vital in the early warning that a predator is over head!
Whats that under its chin?
If you look under the chin of most iguanas you will see a large loose flap of skin. This is called the Dewlap. The Dewlap can be moved in or out. The iguana sticks out its dewlap if it wants to show off or warn attackers. The dewlap also has many blood vessels running through the shallow skin. If it is a hot day, the iguana can stick out its dewlap to let heat escape. If it is a cold day, then the iguana can stand in the sun and stick out its dewlap to absorb as much sun rays as possible to warm up it’s body.
Don't forget to blow your nose
The plants that iguanas eat contain a lot of salt. The salts are stored in sacs in their noses and when these sacs get full, the iguanas "sneeze" them out. There are marine iguanas that live on islands in the Pacific, called the Galapagos Islands. Because these iguanas spend all day eating seaweed off the sea floor, they ingest a lot of salt. Thereore, these iguanas have very large nostrils to “sneeze” out lots of salt. This can look pretty funny when a large group of marine iguanas are sunbathing together constantly sneezing!
WEST INDIAN IGUANAS AND CONSERVATION
The West Indian iguanas (including the iguanas in the Bahamas) are a very special group of iguanas. They are among the most endangered of the world’s lizards. Their habitats are being destroyed for housing or farming. People have also introduced foreign animals to the smalls islands, which eat small iguanas and/or iguana eggs, and destroy the habitats even further.
The Jamaican iguana is one of the rarest lizards in the world! It was thought to have gone extinct in the early 1900's and was rediscovered in 1990. Today, there is an estimated 100 of Jamaican iguanas left in the wild. The reason why there are so few left is mainly due to mankind! Here is a diagram showing all the things that affect the West Indian Iguanas. There are many natural predators that eat young iguanas, and West Indian Iguanas are also vulnerable to hurricanes which destroy their habitats. But humans pose even more problems for iguanas!
Before Europeans came to the West Indies, the iguanas were the largest terrestrial herbivores on the islands. These iguanas play an important role in island ecology. The iguanas eat the fruit of many plants and the seeds are then passed through the gut and are dispersed around the island. Scientists have shown that seeds passing through the gut of iguanas grow faster and stronger than with other seed dispersers. Today, people have drastically reduced the number of these animals on their islands and have therefore drastrically altered the ecology of these islands. To help save these amazing animals, scientists have been trying to relocate iguanas to close, unpopulated islands. In many areas where iguanas are disappearing too quickly, scientists will have to collect them to try to breed them in
zoos
. Zoos will hopefully have the future opportunity to release these iguanas back to untouched wild habitats.
BAHAMIAN ROCK IGUANAS AND CONSERVATION
Endangered species
The Bahamas has three species of iguanas and a total of 7 sub-species.
All of these iguanas belong to the same genus: Cyclura. Some of these sub-species can reach up to 6 feet in total length and weigh nearly twenty pounds.
* above are estimates only, taken from the ecoregional plans done by the University of Miami, Ohio.
All rock iguanas in the Bahamas are considered critically endangered (Appenidix I, CITES). This means that they are illegal to buy or sell internationally. These iguanas are also protected by Bahamian law under the Wildlife protection act and this means that these iguanas are illegal to kill or to keep as pets without a permit.
IGUANAS OF ARDASTRA
Ardastra has three species of iguanas; the San salvador rock iguana, the Mexican spiny tailed iguana and the Green iguana.
San salvador rock iguana - Cyclura rileyi rileyi
The San salvador rock iguana is the largest sub-species of Cyclura rileyi. Though they were once found throughout the main island of San salvador, today they they are only found on five tiny offshore cays (Gaulin, Goulding, Green Low and Manhead cay) and two cays within Great lake (Guana and Pigeon).
Their habitat varies from coastal rock, sand dune, coastal coppice, blackland coppice and mangrove communities.
For more info on the San salvador rock iguanas...
Can the San salvador rock iguanas be saved?...
Mexican spiny-tailed iguana - Ctenosaura similis
There are 13 species belonging to the genus Ctenosaura. The Mexican Spiny-tailed Iguana, also known as the Black iguana, is one of the largest and most conspicuous lizards in Central America, ranging from southern Mexico to Panama. Through human introduction they can now also be found in southern Texas and Florida.
Mexican Spiny-tails inhabit tropical and subtropical mainland environments. Juveniles have been observed spending a lot of time in groups on the ground, only climbing into the lower branches of trees at night, when they are vulnerable to predators. Adults seem to prefer an arboreal lifestyle, descending mainly to sun bathe and nest.
Hatchlings are a brilliant green color and are often confused with juvenile green iguanas, which look very similar. After about a year their color fades into the adult gray. The distinguishing features of the Mexican spiny tail are its tall dorsal crest and large rough spiny scales on its tail.
Newly-hatched Mexican spiny-tailed iguanas are insectivorous, gradually shifting to a more herbivorous diet as they grow. Although adults feed mainly on plants they are opportunistic and will often take small birds, eggs, crabs and rodents. C. similis has been reported to produce 5 to 8 clutches annually, consisting of 12-88 eggs each. After a three month incubation period the hatchlings emerge. A small percentage will live through the first year and an even smaller percentage will live to adult hood. Young iguanas are highly predated upon by snakes, hawks, magpies and raccoons.
Most species of Ctenosaura are in peril. Contributing factors include habitat destruction and hunting for food and sport. The Spiny-tailed iguana is collected for the pet trade by the hundreds, compounding population declines. The animals that have found their way to Texas and Florida have adapted to their new environment and proliferate well. Unfortunately, as a non-native, invasive species they are considered a pest.
Our two male Mexican spiny-tails, who were kindly donated to us, are quite content spending all day basking in the sun.
Green iguana - Iguana iguana
These iguanas are the best known because they are the most common iguanas in captivity. They are originally from Central and South America but today they have been introduced to many regions of the world. Green Iguanas were introduced to Florida in the 1960's and today they are establishing themselves in the Bahamas, mainly New Providence.
The green iguana is also a large iguana, which can grow up to three to four feet long. Like the name suggests, Green iguanas are generally green in color and have black stripes on their tails. They can range from a brilliant green to grey to brown in color. This coloration enables these iguanas to camouflage perfectly in their natural habitat, tropical rain forests.
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