Jamaican iguana | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Iguania |
Family: | Iguanidae |
Genus: | Cyclura |
Species: | C. collei |
Binomial name | |
Cyclura collei Gray, 1845 | |
The Jamaican iguana (Cyclura collei), also known commonly as Colley's iguana, is a large species of lizard in the family Iguanidae. The species is endemic to Jamaica. It is critically endangered, even considered extinct between 1948 and 1990. Once found throughout Jamaica and on the offshore islets Great Goat Island and Little Goat Island, it is now confined to the forests of the Hellshire Hills.
The specific name, collei, is in honor of someone named Colley. John Edward Gray, who originally described this species in 1845, referred to it as "Colley's Iguana". Unfortunately, Gray did not further specify who Colley was. [3]
The Jamaican iguana is a large, heavy-bodied lizard, primarily green to salty blue in color with darker olive-green coloration on the shoulders. [4] Three dark broad chevrons extend from the base of the neck to the tail on the animal's back, with dark olive-brown zigzag spots. [4] The dorsal crest scales are somewhat brighter bluish-green than the body. [4] The body surfaces are blotched with a yellowish blotched color breaking up into small groups of spots. [4] Wild individuals, particularly nesting females, often appear deep reddish-brown in color after digging in the coarse ferralic soils of the Hellshire Hills region. [4]
The Jamaican iguana is the second-largest land animal native to Jamaica, with only the Jamaican boa weighing more. Males can grow to over 2 kilograms (4.4 lb) and 428 millimetres (16.9 in) in length whereas females are slightly smaller, growing to 378 millimetres (14.9 in) in length. [1] Males also possess large femoral pores on the undersides of their thighs, which are used to release pheromones. [5] The pores of the female are smaller and they do not have a dorsal crest as high as the male's, making the animal somewhat sexually dimorphic. [5]
According to Sir Hans Sloane, a physician and botanist who visited Jamaica in 1688, iguanas were once common throughout Jamaica. [1] The Jamaican iguana declined dramatically during the second half of the 19th century, after the introduction of the small Asian mongoose as a form of rat and snake control, until it was believed to exist only on the Goat islands near the Hellshire hills. [1]
The Jamaican iguana was believed to be extinct in 1948. [6] A dead adult specimen was found in 1970. The species was rediscovered in August 1990 when a live adult male iguana was chased into a hollow log by a dog of Edwin Duffus, a hog hunter in the Hellshire Hills. By the time he got there, the dog had injured the animal but that was the iguana that was taken to the Hope Zoo. A remnant population was discovered soon after. [6] [7] The Hellshire Hills area is the only area of Jamaica where this iguana is found. It is relegated to two dense populations that consist of scattered individuals. [1] [6] They were once prevalent in the island but are now only found in the dry, rocky, limestone forest areas of St. Catherine. [1] Before it was rediscovered in 1990, the iguana was last seen alive on Goat Island off the coast of Jamaica in 1940. [1]
Like all Cyclura species the Jamaican iguana is primarily herbivorous, consuming leaves, flowers and fruits from over 100 different plant species. [4] This diet is very rarely supplemented with insects and invertebrates such as snails. [4] However, these could simply be eaten incidentally while it consumes the leaves the invertebrates live on.
The Jamaican iguana was believed to be extinct dating to 1948. After its rediscovery in 1990, a study showed only that there were only 50 survivors of the "rarest lizard in the world". [6] [7] The IUCN lists it as a Critically Endangered Species. [1]
The single direct cause for the Jamaican iguana's decline can be attributed to the introduction of the small Asian mongoose (Urva auropunctata) as a form of snake-control. [7] [8] The mongoose came to rely upon hatchling iguanas as a prime source of food, prompting the creation of the Headstart facility and a proposed program to eradicate the feral mongoose. [7]
The biggest current threat to the animals' existence is no longer from the spread of the mongoose, but from the charcoal industry. [4] [9] Charcoal burners rely on hardwood trees from the Hellshire Hills to make charcoal. [8] [9] As this is the primary refuge for the iguanas, the burners have been threatening the research teams who protect the iguanas. [9]
A consortium of twelve zoos, also from within the USA donated and constructed a Headstart Facility at Hope Zoo, used for the rearing of eggs and hatchlings brought from the wild. [1] [6] [9] From within the safety of this environment, they are reared until they are large enough to survive in the wild and predators such as the mongoose are no longer a threat, a process known as "headstarting". [1] [7] [10] The Headstart facility also carries out health screening prior to the release of specimens. [6] [10] [11] This health screening has been used to baseline the normal physiologic values of the species, identifying potential future problems due to parasites, diseases, etc. which might threaten the population. [12]
The US captive population doubled in size in August 2006 with the hatching of 22 Jamaican rock iguanas at the Indianapolis Zoo. [9] This was the first successful captive breeding and hatching outside of Jamaica. [9]
In a 2021 assessment it was estimated that today there are 500-600 mature individuals and the recovery potential for the species is high. [1]
The Turks and Caicos rock iguana is a species of lizard endemic to the Turks and Caicos islands. This small iguana can reach 30 in (76 cm) and becomes mature at seven years and may live for twenty. A single clutch of up to nine eggs is laid each year, and these take three months to hatch. This iguana is mostly herbivorous, but supplements this by adding some animal matter to its diet.
The blue iguana, also known as the Grand Cayman ground iguana, Grand Cayman blue iguana or Cayman Island rock iguana, is an endangered species of lizard which is endemic to the island of Grand Cayman. It was previously considered to be a subspecies of the Cuban iguana, Cyclura nubila, but in a 2004 article Frederic J. Burton reclassified it as a separate species because according to him the genetic differences discovered four years earlier between the different C. nubila populations warranted this interpretation. The blue iguana is one of the longest-living species of lizard.
The Mona ground iguana is a critically-endangered species of rock iguana, endemic to Mona Island, Puerto Rico. It is one of the island nation’s few large land animals, and it is the largest endemic terrestrial lizard in the country, and one of the biggest rock iguanas within the Antilles. It was previously considered a subspecies of the rhinoceros iguana.
Brachylophus fasciatus, the Lau banded iguana, is an arboreal species of lizard endemic to the Lau Islands of the eastern part of the Fijian archipelago. It is also found in Tonga, where it was probably introduced by humans. It is one of the few species of iguanas found outside of the New World and one of the most geographically isolated members of the family Iguanidae. Populations of these iguanas have been declining over the past century due to habitat destruction, and more significantly, the introduction of mongoose and house cats to the islands.
The rhinoceros iguana is an endangered species of iguana that is endemic to the Caribbean island of Hispaniola and its surrounding islands. A large lizard, they vary in length from 60 to 136 centimetres, and skin colours range from a steely grey to a dark green and even brown. Their name derives from the bony-plated pseudo-horn or outgrowth which resembles the horn of a rhinoceros on the iguana's snout. It is known to coexist with the Ricord's iguana ; the two species are the only taxa of rock iguana to do so.
Ctenosaura bakeri, also known as the Utila spiny-tailed iguana, Baker's spinytail iguana, swamper or wishiwilly del suampo, is a critically endangered species of spinytail iguana endemic to the island of Utila, one of the Islas de la Bahía off the coast of Honduras in the Caribbean.
The northern Bahamian rock iguana is a species of lizard of the genus Cyclura that is found on Andros Island and the Exuma islands in the Bahamas. Its status on the IUCN Red List is vulnerable, with a wild population of less than 5,000 animals.
The Cuban rock iguana, also known as the Cuban ground iguana or Cuban iguana, is a species of lizard of the iguana family. It is the second largest of the West Indian rock iguanas, one of the most endangered groups of lizards. A herbivorous species with a thick tail and spiked jowls, it is one of the largest lizards in the Caribbean.
Cyclura ricordii, also known as Ricord's ground iguana or Ricord's rock iguana, is an endangered species of medium-sized rock iguana, a large herbivorous lizard. It is endemic to the island of Hispaniola. It is known to coexist with the nominate subspecies of the rhinoceros iguana ; the two species are the only taxa of rock iguana to do so. The natural habitats of its three subpopulations are hot, dry, wooded savanna on limestone with access to soil and sandy flats in southern Hispaniola. It is threatened by predation by introduced predators and habitat loss, due to overgrazing and charcoal manufacture.
The Acklins ground iguana, also commonly known as the 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 family Iguanidae.
Cyclura rileyi, commonly known as the Bahamian rock iguana or the San Salvador rock iguana, is a critically endangered species of lizard in the family Iguanidae. The species is native to three island groups in the Bahamas, and is in decline due to habitat encroachment by human development and predation by feral dogs and cats. There are three subspecies: the Acklins ground iguana, the White Cay iguana, and the nominotypical subspecies.
The Andros Island iguana or Andros 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 Grand Bahama. Its status is Endangered, with a wild population of 3,500 animals, and it can be found on the IUCN Red List.
Cyclura cornuta onchiopsis, the Navassa Island iguana, was a subspecies of rhinoceros iguana that was found on the Caribbean island of Navassa.
Cyclura nubila caymanensis, the Lesser Caymans iguana, Cayman Brac iguana, Cayman Island brown iguana or Sister Isles iguana, is a critically endangered subspecies of the Cuban iguana. It is native to two islands to the south of Cuba: Cayman Brac and Little Cayman, which are also known as the Sister Isles due to their similar shapes and close proximity to each other. The population of this subspecies has been impacted by habitat encroachment by human development and is likely being destroyed due to predation by cats, the population on Cayman Brac has remained particularly small for decades.
Cyclura cychlura inornata, the Allen Cays rock iguana or Allen Cays iguana, is a subspecies of the northern Bahamian rock iguana that is found on Allen's Cay and adjacent islands in the Bahamas. Its status in the IUCN Red List is critically endangered. The population has been growing over the last century. Although it was considered extinct in 1916, there are as of 2018 at least 482 mature adult animals counted on two islands, Leaf Cay and U Cay, and a few hundred on at least five other nearby islands where they have recently spread to by unknown means, as well as many juveniles.
Cyclura cychlura figginsi, known by the common name of guana and sometimes called the Exuma Island iguana in the international literature, is a subspecies of the northern rock iguana, C. cychlura, that is found on the Exuma island chain in the Bahamas with an estimated wild population of 1,300 animals in 2004, it has been listed on the IUCN Red List as critically endangered.
Cyclura rileyi cristata, 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.
Cyclura is a genus of lizards in the family Iguanidae. Member species of this genus are commonly known as "cycluras" and only occur on islands in the West Indies. Rock iguanas have a high degree of endemism, with a single species or subspecies originating on an individual island.
Cyclura pinguis, the Anegada rock iguana, Anegada ground iguana or stout iguana, is a critically endangered species of lizard of the genus Cyclura belonging to the family Iguanidae. The species can be found exclusively in the islands of Anegada and Guana. Historically, it inhabited the islands of Puerto Rico and Saint Thomas; however, the animal's original range has been greatly diminished over prehistory.
Headstarting is a conservation technique for endangered species, in which young animals are raised artificially and subsequently released into the wild. The technique allows a greater proportion of the young to reach independence, without predation or loss to other natural causes.