Habitat and Ecology
Rugged limestone outcroppings comprise much of the Hellshire Hills with coarse red ferralic soil accumulating in crevices and depressions. Soil suitable for nesting is comparatively scarce. The vegetation of the Hellshire Hills consists of tropical dry forest, one of the world’s most threatened ecosystems. Jamaican Iguanas are found only in the remotest sections of the Hellshire Hills where the forest remains in good condition. The Jamaican Iguana feeds on leaves, fruits, and flowers of a wide variety of plant species, supplemented occasionally by animal matter, including snails and insects.
Since 1991 the known communal nest sites have been observed intensively (Vogel 1994, Wilson et al. 2004) and individuals have been marked. Nesting occurs in underground burrows, filled with loose soil, and is guarded for several days. Gravid female iguanas begin digging trial holes long before egg laying. Females deposit their eggs in mid-June, and hatchlings emerge approximately 85-87 days later. Clutch sizes range from 6-20 eggs depending on the size and age of the female. Hatching success varies from 0 to 100% and appears to be related to maternal body size and seasonal rainfall extremes (B. Wilson and R. van Veen pers. comms. 2010).
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Critically Endangered
- 1994Endangered(Groombridge 1994)
- 1990Endangered(IUCN 1990)
Date Listed: 06/22/1983
Lead Region: Foreign (Region 10)
Where Listed: Entire
Population location: Entire
Listing status: E
For most current information and documents related to the conservation status and management of Cyclura collei , see its USFWS Species Profile
In 2012, Cyclura collei was included among the world's 100 most threatened species in a report by the IUCN Species Survival Commission and the Zoological Society of London.
At the beginning of the 20th century, the Jamaican Iguana was thought to have survived only on the Goat Islands, two small islets offshore from the Hellshire Hills. The iguana was believed extinct after this population disappeared in the 1940s. However, the continued survival of the Jamaican Iguana in the Hellshire Hills was confirmed in 1970 (Woodley 1980) from a single individual and again in 1990, both found by hunter’s dogs. A preliminary survey in 1990 revealed a small surviving population of fewer than 100 animals living in the least disturbed central and western sections of the Hellshire Hills. Two active nesting sites were also found though juvenile recruitment appeared to be minimal. Iguanas appear to have disappeared from northern and eastern sections of the Hellshire Hills because of extensive logging for charcoal production, use of dogs for pig hunting, and human settlements (CBSG 1993, B. Wilson and R. van Veen pers. comms. 2010).
Today, because of intensive predator control and the reintroduction of headstarted iguanas, the population in the central core area only is increasing. Field research has documented several milestones in the core area including: a greater than two-fold increase in the number of nesting females, successful reproduction among repatriated releases, and long-term survival and reproductive maturation of hatchlings (B. Wilson and R. van Veen pers. comms. 2010). The population trend for iguanas wandering outside the area protected by the mongoose trapline is unknown.
Another significant problem is illegal tree cutting in the forest for use in charcoal production, a local industry that provides income to an estimated 10,000 Jamaicans. Approximately one-third of the Hellshire Hills is badly degraded as a result of this enterprise. Development projects proposing large-scale limestone mining, human settlements, and tourism also threaten the eastern half of the Hellshire Hills. Although a few localized limestone quarries might have only limited impact on the iguanas and their habitat, the new roads that would be constructed to facilitate the mining process would undoubtedly allow charcoal burners, pig hunters, and other forest users to migrate further into the forest.
The Jamaican Iguana is listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), however, this iguana has not been utilized by humans since well before the late 1800s.
Although most of Jamaica’s remaining ecologically important forests, including the Hellshire Hills, are owned by the government and protected by law under the Forest Act of 1996, the Act has received little enforcement. The Hellshire Hills is currently part of the Portland Bight Protected Area (PBPA). Declared in 1999, the PBPA is Jamaica’s largest protected area and includes both of the Goat Islands. Designation as a protected area provides a promising legal instrument to prevent the expansion of large-scale development projects in the Hellshire Hills.
Following the rediscovery of the species in 1990, a local Jamaican Iguana Research and Conservation Group (JIRCG) was formed, comprising representatives from the University of the West Indies, the Natural Resources Conservation Authority, Hope Zoological Gardens, and the Institute of Jamaica. Together with a group of international iguana specialists, the JIRCG held an IUCN-sponsored workshop in Kingston in 1993, which developed a Population and Habitat Viability Assessment and a comprehensive plan for recovering this species in the wild (CBSG 1993). During the workshop, it became clear the current mortality level of juvenile iguanas in the wild was too high to permit survival of the population. This led to recommendations for a captive headstarting program at the Hope Zoo, which has resulted in the release of 138 iguanas back into the Hellshire Hills from 1996 through 2010.
The JIRCG is now known as the Jamaican Iguana Recovery Group (JIRG) and includes international collaborators. In addition to captive headstarting and release, the group continues to survey the wider Hellshire Hills, monitors individuals in the core area centered around the known nesting sites, and is detailing a complete natural history of the species (Wilson et al. 2004; Wilson and van Veen 2005, 2008). Repatriated animals have demonstrated high survivorship and are now integrated into the breeding population. Complementary predator control in the core area has resulted in improved recruitment attributable to enhanced survival among younger age classes. The group also focuses on education, international awareness, and habitat protection and improvement.
In 1994, an ex situ captive population was initiated with the importation of 12 iguanas to three U.S. institutions (Indianapolis Zoo, Fort Worth Zoo, and Gladys Porter Zoo). In 1996, this group was supplemented by a second importation of 12 iguanas to the San Diego Zoo, Central Florida Zoo, and Sedgwick County Zoo. After successful breeding in the U.S., the program has expanded to Fresno, Miami, and St. Louis zoos. The primary purpose of the U.S. captive population is to promote education, awareness, and provide support for the ongoing recovery effort of the wild population. Additionally, the captive colony is managed for long-term maintenance of genetic diversity in the event of catastrophic loss in the wild population (Grant 2010).
As a further safeguard against extinction, captive-reared juvenile iguanas may also be used to establish satellite populations on the Goat Islands, provided the islands can be rendered free of predators and goats. A priority goal, highlighted in the 2006 Jamaican Iguana Species Recovery Plan, outlines establishing a dry forest biodiversity reserve on these offshore islets and is arguably the single most critical conservation activity ensuring the long-term recovery of the Jamaican Iguana.
The species is listed on CITES Appendix I.
The Jamaican iguana (Cyclura collei) is a large species of lizard of the genus Cyclura endemic to Jamaica. It is the largest native land animal in the country, and 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 Jamaican iguana's generic 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.
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.
Anatomy and morphology
The Jamaican iguana is a large heavy-bodied lizard primarily green to salty blue in color with darker olive-green coloration on the shoulders. 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. The dorsal crest scales are somewhat brighter bluish-green than the body. The body surfaces are blotched with a yellowish blotched color breaking up into small groups of spots. Wild individuals, particularly nesting females, often appear deep reddish-brown in color after digging in the coarse ferralic soils of the Hellshire Hills region. Male Jamaican iguanas grow to approximately 428 millimetres (16.9 in) in length whereas females are slightly smaller, growing to 378 millimetres (14.9 in) in length. Males also possess large femoral pores on the undersides of their thighs, which are used to release pheromones. 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.
According to Sir Hans Sloane, a physician and botanist who visited Jamaica in 1688, iguanas were once common throughout Jamaica. The Jamaican iguana declined dramatically during the second half of the 19th century, after the introduction of the Indian mongoose as a form of rat and snake control, until it was believed to exist only on the Goat islands near the Hellshire hills.
The Jamaican iguana was believed to be extinct in 1948. A dead adult specimen was found in 1970, and the species was rediscovered in 1990 when a live iguana was captured by a hog hunter in the Hellshire Hills and a remnant population was discovered soon after. 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. They were once prevalent in the island but are now only found in the dry, rocky, limestone forest areas of St. Catherine. Before it was rediscovered in 1990, the iguana was last seen alive on Goat Island off the coast of Jamaica in 1940.
Like all Cyclura species the Jamaican iguana is primarily herbivorous, consuming leaves, flowers and fruits from over 100 different plant species. This diet is very rarely supplemented with insects and invertebrates such as snails. 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". The IUCN lists it as a Critically Endangered Species.
Causes of decline
The single direct cause for the Jamaican iguana's decline can be attributed to the introduction of the small Asian mongoose (Herpestes javanicus) as a form of snake-control. 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.
The biggest current threat to the animals' existence is no longer from the spread of the mongoose, but from the charcoal industry. Charcoal burners rely on hardwood trees from the Hellshire Hills to make charcoal. As this is the primary refuge for the iguanas, the burners have been threatening the research teams who protect the iguanas.
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. 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". The Headstart facility also carries out health screening prior to the release of specimens. 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.
The US captive population doubled in size in August 2006 with the hatching of 22 Jamaican rock iguanas at the Indianapolis Zoo. This was the first successful captive breeding and hatching outside of Jamaica.
- Grant, T.D., Gibson, R. & Wilson, B.S. (2010). Cyclura collei. The IUCN Red List of Threatened Species. Version 2014.2.
- Sanchez, Alejandro. "Family Iguanidae: Iguanas and Their Kin". Father Sanchez's Web Site of West Indian Natural History Diapsids I: Introduction; Lizards. Kingsnake.com. Retrieved November 26, 2007.
- Beolens B, Watkins M, Grayson M. 2011. The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Cyclura collei, pp. 56-57).
- Vogel, Peter (July 1, 2005), Jamaican Iguana Cyclura Collei, Iguana Specialist Group, archived from the original on January 14, 2006
- Gibson (1996). Cyclura collei. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on May 11, 2006.
- De Vosjoli, Phillipe; David Blair (1992), The Green Iguana Manual, Escondido, California: Advanced Vivarium Systems, ISBN 1-882770-18-8
- Gabriel, Deborah (2005). "Saving the Jamaican Iguana". Reptile Treasures Newsletter. Retrieved September 9, 2007.
- Wilson, Byron; Alberts, Allison; Grahm, Karen; Hudson, Richard (2004), Survival and Reproduction of Repatriated Jamaican Iguanas, Iguanas: Biology and Conservation (University of California Press): 220–231, ISBN 978-0-520-23854-1
- Williams-Raynor, Petre (February 11, 2007). "The Jamaican iguana (Cyclura collie)". The Jamaican Observer.
- Hudson, Rick (4/1/2007), Big Lizards, Big Problems, Reptiles Magazine 15 (4): 56 Check date values in:
- Alberts, Allison; Lemm, Jeffrey; Grant, Tandora; Jackintell, Lori (2004). "Testing the Utility of Headstarting as a Conservation Strategy for West Indian Iguanas". Iguanas: Biology and Conservation. University of California Press. p. 210. ISBN 978-0-520-23854-1.
- Iverson, John; Smith, Geoffrey; Pieper, Lynne (2004), Factors Affecting Long-Term Growth of the Allen Cays Rock Iguana in the Bahamas, Iguanas: Biology and Conservation (University of California Press): 200, ISBN 978-0-520-23854-1
- Knapp, Charles R.; Hudson, Richard (2004), Translocation Strategies as a Conservation Tool for West Indian Iguanas, Iguanas: Biology and Conservation (University of California Press): 199–209, ISBN 978-0-520-23854-1
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