Cyclura
Encyclopedia
Cyclura is a genus
of lizard
s from the family Iguanidae
. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies. Rock iguanas have a high degree of endemism, with a single species or subspecies restricted to individual islands.
name (Cyclura) is derived from the Ancient Greek
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura.
Currently there are nine described species and eight subspecies identified in this genus.
and sparse vegetation ranging from only moderately dry acacia
forest to much drier mesquite
and cactus
habitats. These are nonvolcanic islands made up of heavily eroded limestone
which form natural caves that the iguanas use as retreats.
All rock iguanas are herbivorous, consuming leaves, flowers, berries, and fruits from different plant species. A study in 2000 by Allison Alberts of the San Diego Zoo
revealed that seeds passing through the digestive tracts of rock iguanas germinate more rapidly than those that do not. These seeds in the fruits consumed by cycluras have an adaptive advantage by sprouting before the end of very short rainy seasons. The iguanas are an important means of distributing these seeds to new areas (particularly if females migrate to nesting sites) and, as the largest native herbivores of many island ecosystem
s, they are essential for maintaining the balance between climate and vegetation. Their diet is very rarely supplemented with insect larvae, crabs, slugs, dead birds, and fungi; individual animals do appear to be opportunistic carnivores.
Like other herbivorous lizards, the rock iguanas are presented with a special problem for osmoregulation
: plant matter contains more potassium
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
. In the case of the rock iguana which consumes large amounts of vegetation, these excess salt ions are excreted through their salt gland
in the same manner as birds.
The record for the longest lived captive-born rock iguana is held by a Lesser Caymans iguana, which lived for 33 years in captivity.
A Blue iguana
captured on Grand Cayman
in 1950 by naturalist Ira Thompson was imported to the United States
in 1985 by Ramon Noegel and sold to reptile importer and breeder, Tom Crutchfield. Crutchfield loaned Godzilla to the Gladys Porter Zoo
in Brownsville, Texas
in 1997. The lizard was named Godzilla
by the zoo staff and was kept until his death in 2004. Thompson estimated the iguana to be 15 years of age at the time of its capture. This lizard may have been the word's longest-living recorded lizard at 69 years of age, having spent 54 years in captivity.
crests in addition to enlarged femoral pore
s on their thighs, which are used to release pheromones, females have shorter crests than the males making the animals somewhat sexually dimorphic
.
Although the particulars vary slightly among species and subspecies, the rock iguanas reach sexual maturity at three to seven years of age. Females become sexually mature at two to five years of age. Males can be highly territorial
with the notable exception of the Exuma Island Iguana
. Mating takes place at the beginning of or just prior to the first rainy season of the year (May to June) and lasts for two to three weeks. Females lay from 2 to 34 eggs, with an average clutch size of 17 within 40 days. Females of most species guard their nests for several days after laying their eggs, and incubation lasts approximately 85 days. It has been noted that Cyclura eggs are among the largest lizard eggs produced in the world.
, four taxa are endangered and three species have been identified as Vulnerable, one species is believed to be extinct in the wild. In addition to small numbers typical of endemic island-dwelling animals, wild populations of these lizards are directly and indirectly impacted by land development, overgrazing by domestic and feral
livestock and predation by humans and feral mammals such as hogs, cat
s, rat
s, dog
s, and mongoose
s.
The Indianapolis Zoo
is involved in research and conservation of all 16 taxa of West Indian iguanas. This includes collaborative work on establishing baseline biological values in captive and wild iguanas, and scientific investigation, conservation efforts, field research and captive breeding programs. The Indianapolis Zoo has been involved in the Dominican Republic
for almost ten years and will continue its research and conservation efforts with the Ricord's iguana
.
The project's goals are:
Genus
In 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...
of lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s from the family Iguanidae
Iguanidae
Iguanidae is a family of lizards, composed of iguanas and related species.-Classification of Iguanidae:Two different classification schemes have been used to define the structure of this family. These are the "traditional" classification and the classification presented by Frost et al. .Frost et...
. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies. Rock iguanas have a high degree of endemism, with a single species or subspecies restricted to individual islands.
Taxonomy
The genericGenus
In 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...
name (Cyclura) is derived from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura.
Currently there are nine described species and eight subspecies identified in this genus.
- Turks and Caicos Rock Iguana, Cyclura carinata
- Bartsch's Iguana, Cyclura carinata bartschiCyclura carinata bartschiBartsch's iguana or Booby Cay iguana is an endangered subspecies of lizard of the genus Cyclura endemic to a single cay, Booby Cay, in the Turks and Caicos islands.-Taxonomy:...
- Bartsch's Iguana, Cyclura carinata bartschi
- Jamaican Iguana, Cyclura collei
- Rhinoceros Iguana, Cyclura cornutaRhinoceros IguanaThe Rhinoceros Iguana is a threatened species of lizard in the family Iguanidae that is primarily found on the Caribbean island of Hispaniola, shared by the Republic of Haiti and the Dominican Republic. They vary in length from 61 to 137 cm and skin colors range from a steely gray to a dark green...
- Navassa Island Iguana (believed to be extinct), Cyclura cornuta onchiopsisCyclura cornuta onchiopsisThe Navassa Island iguana was a subspecies of rhinoceros iguana of the genus Cyclura that was found on the Caribbean island of Navassa...
- Mona Ground Iguana, Cyclura cornuta stejnegeriMona Ground IguanaThe Mona ground iguana is a subspecies of the rhinoceros iguana . It is endemic to Mona Island, Puerto Rico and is the largest native terrestrial lizard in Puerto Rico.- Taxonomy :...
- Navassa Island Iguana (believed to be extinct), Cyclura cornuta onchiopsis
- Andros Island Iguana, Cyclura cychlura cychluraCyclura cychlura cychluraThe Andros Island Iguana is an endangered subspecies of Northern Bahamian Rock Iguana of the genus Cyclura that is found on Andros Island on the western edge of the Grand Bahama Bank...
- Exuma Island Iguana, Cyclura cychlura figginsiCyclura cychlura figginsiCyclura cychlura figginsi, commonly known as the Exuma Island Iguana, is a critically endangered subspecies of Northern Bahamian Rock Iguana that is found on the Exuma island chain in the Bahamas with a wild population of 1,300 animals, it is listed on the IUCN Red List.-Taxonomy:The Exuma Island...
- Allen Cays Iguana, Cyclura cychlura inornataCyclura cychlura inornataThe Allen Cays Rock Iguana is an endangered subspecies of the Northern Bahamian Rock Iguana that is found on Allen Cay in the Bahamas...
- Exuma Island Iguana, Cyclura cychlura figginsi
- Grand Cayman Blue Iguana, Cyclura lewisiBlue IguanaThe Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
- Cuban Iguana, Cyclura nubilaCyclura nubilaCyclura nubila, also known as the Cuban rock iguana, Cuban ground iguana, or Cuban iguana, is a species of lizard of the iguana family. It is the largest of the West Indian rock iguanas , one of the most endangered groups of lizards...
- Lesser Caymans Iguana, Cyclura nubila caymanensisCyclura nubila caymanensisThe Lesser Caymans Iguana or Cayman Brac Iguana or Cayman Island Brown Iguana or Sister Isles Iguana is a critically endangered subspecies of the Cuban Iguana...
- Lesser Caymans Iguana, Cyclura nubila caymanensis
- Anegada Ground Iguana, Cyclura pinguisCyclura pinguisThe Stout Iguana or Anegada Ground Iguana is a critically endangered species of lizard of the genus Cyclura belonging to the Iguanidae family. The species can be found exclusively in the island of Anegada...
- Ricord's Iguana, Cyclura ricordiCyclura ricordiThe Hispaniolan Ground Iguana, Ricord's Ground Iguana, Ricord's Rock Iguana, or Ricord's Iguana is a critically endangered species of rock iguana....
- San Salvador Iguana, Cyclura rileyiCyclura rileyiCyclura rileyi, commonly known as the San Salvador Rock Iguana or Bahamian Rock Iguana, is a critically endangered species of lizard of the genus Cyclura native to three island groups in the Bahamas. The species is in decline due to habitat encroachment by human development and predation by feral...
- White Cay Iguana, Cyclura rileyi cristataCyclura rileyi cristataCyclura rileyi cristata, commonly known as the White Cay Iguana or Sandy Cay Rock Iguana, is a critically endangered subspecies of lizard of the genus Cyclura native to a single cay in the Bahamas: White Cay located in the Southern Exumas.-Taxonomy:The White Cay iguana is an endangered subspecies...
- Acklins Iguana, Cyclura rileyi nuchalisAcklins Ground IguanaCyclura rileyi nuchalis, commonly known as the Acklins Ground Iguana or Watling Island Iguana, is an endangered subspecies of lizard of the genus Cyclura it is one of three subspecific forms of Cyclura rileyi in the Iguanidae family....
- White Cay Iguana, Cyclura rileyi cristata
Habitat
Rock iguanas most often inhabit subtropical areas of West Indian dry forest biomes characterized by eroded limestoneLimestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
and sparse vegetation ranging from only moderately dry acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
forest to much drier mesquite
Mesquite
Mesquite is a leguminous plant of the Prosopis genus found in northern Mexico through the Sonoran Desert and Chihuahuan Deserts, and up into the Southwestern United States as far north as southern Kansas, west to the Colorado Desert in California,and east to the eastern fifth of Texas, where...
and cactus
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
habitats. These are nonvolcanic islands made up of heavily eroded limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
which form natural caves that the iguanas use as retreats.
Diet and longevity
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
revealed that seeds passing through the digestive tracts of rock iguanas germinate more rapidly than those that do not. These seeds in the fruits consumed by cycluras have an adaptive advantage by sprouting before the end of very short rainy seasons. The iguanas are an important means of distributing these seeds to new areas (particularly if females migrate to nesting sites) and, as the largest native herbivores of many island ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s, they are essential for maintaining the balance between climate and vegetation. Their diet is very rarely supplemented with insect larvae, crabs, slugs, dead birds, and fungi; individual animals do appear to be opportunistic carnivores.
Like other herbivorous lizards, the rock iguanas are presented with a special problem for osmoregulation
Osmoregulation
Osmoregulation 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 potassium
Potassium
Potassium 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 has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
. In the case of the rock iguana which consumes large amounts of vegetation, these excess salt ions are excreted through their salt gland
Salt gland
The 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...
in the same manner as birds.
The record for the longest lived captive-born rock iguana is held by a Lesser Caymans iguana, which lived for 33 years in captivity.
A Blue iguana
Blue Iguana
The Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
captured on Grand Cayman
Grand Cayman
Grand 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...
in 1950 by naturalist Ira Thompson was imported to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1985 by Ramon Noegel and sold to reptile importer and breeder, Tom Crutchfield. Crutchfield loaned Godzilla to the Gladys Porter Zoo
Gladys Porter Zoo
Gladys Porter Zoo is a zoological and botanical park located in Brownsville, Texas. The zoo officially opened on September 3, 1971, and currently averages 375,000 visitors annually. Situated on , the zoo houses about 400 animal species and over 250 tropical and neo-tropical species and subspecies...
in Brownsville, Texas
Brownsville, Texas
Brownsville is a city in the southernmost tip of the state of Texas, in the United States. It is located on the northern bank of the Rio Grande, directly north and across the border from Matamoros, Tamaulipas, Mexico. Brownsville is the 16th largest city in the state of Texas with a population of...
in 1997. The lizard was named Godzilla
Godzilla
is a daikaijū, a Japanese movie monster, first appearing in Ishirō Honda's 1954 film Godzilla. Since then, Godzilla has gone on to become a worldwide pop culture icon starring in 28 films produced by Toho Co., Ltd. The monster has appeared in numerous other media incarnations including video games,...
by the zoo staff and was kept until his death in 2004. Thompson estimated the iguana to be 15 years of age at the time of its capture. This lizard may have been the word's longest-living recorded lizard at 69 years of age, having spent 54 years in captivity.
Reproduction
Males of each species of rock iguana are larger than females and have more prominent dorsalDorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
crests in addition to enlarged femoral pore
Femoral pore
Femoral pores are a part of a holocrine secretory gland found on the inside of the thighs of certain lizards and amphisbaenians which releases pheromones to attract mates or mark territory. In certain species only the male has these pores and in other species, both sexes have them, with the males...
s on their thighs, which are used to release pheromones, females have shorter crests than the males making the animals somewhat sexually dimorphic
Sexual dimorphism
Sexual 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:...
.
Although the particulars vary slightly among species and subspecies, the rock iguanas reach sexual maturity at three to seven years of age. Females become sexually mature at two to five years of age. Males can be highly territorial
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
with the notable exception of the Exuma Island Iguana
Cyclura cychlura figginsi
Cyclura cychlura figginsi, commonly known as the Exuma Island Iguana, is a critically endangered subspecies of Northern Bahamian Rock Iguana that is found on the Exuma island chain in the Bahamas with a wild population of 1,300 animals, it is listed on the IUCN Red List.-Taxonomy:The Exuma Island...
. Mating takes place at the beginning of or just prior to the first rainy season of the year (May to June) and lasts for two to three weeks. Females lay from 2 to 34 eggs, with an average clutch size of 17 within 40 days. Females of most species guard their nests for several days after laying their eggs, and incubation lasts approximately 85 days. It has been noted that Cyclura eggs are among the largest lizard eggs produced in the world.
Conservation status
Every species and subspecies of rock iguana is endangered. Nine of these taxa are Critically Endangered, meaning there are fewer than 250 of each species or subspecies left in wild populations and in danger of ExtinctionExtinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, four taxa are endangered and three species have been identified as Vulnerable, one species is believed to be extinct in the wild. In addition to small numbers typical of endemic island-dwelling animals, wild populations of these lizards are directly and indirectly impacted by land development, overgrazing by domestic and feral
Feral
A 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...
livestock and predation by humans and feral mammals such as hogs, cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s, rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s, dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, and mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
s.
Recovery programs
In 1990, the American Zoo and Aquarium Association (AZA) designated the genus Cyclura as their highest priority. Their first project was a captive breeding program for the Grand Cayman iguana, which at the time was the most critically endangered of all the species of Cyclura.The Indianapolis Zoo
Indianapolis Zoo
The Indianapolis Zoo in Indianapolis, Indiana, United States, first opened to the public in 1964. Its current home in White River State Park was opened in 1988 with a size of . The zoo hosts more than a million visitors each year and plays a role in worldwide conservation and research, including...
is involved in research and conservation of all 16 taxa of West Indian iguanas. This includes collaborative work on establishing baseline biological values in captive and wild iguanas, and scientific investigation, conservation efforts, field research and captive breeding programs. The Indianapolis Zoo has been involved in the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
for almost ten years and will continue its research and conservation efforts with the Ricord's iguana
Cyclura ricordi
The Hispaniolan Ground Iguana, Ricord's Ground Iguana, Ricord's Rock Iguana, or Ricord's Iguana is a critically endangered species of rock iguana....
.
- to work with the Ricord’s Iguana Recovery Group to implement the ISG’s Species Recovery Plan.
- to conduct a census of iguanas on Isla Cabritos, Dominican Republic.
- to determine vitamin D status of captive West Indian iguanas at the Zoo before and after exposure to sunlight.
- to continue to develop long-term captive breeding programs for Grand Cayman Island Blue iguanas and Jamaican iguanas at the Indianapolis Zoo.
- to work in partnership with ZOODOM (the national zoo of the Dominican Republic) to develop a long-term captive breeding and husbandry program for Ricord’s iguanas.
- to develop an education program for West Indian Iguanas and their habitats.