Added 7 January 2014.

A look at the

Genus Cyclura - Rock Iguanas

Family IGUANIDAE [IGUANINAE]

Genus Cyclura - Rock-, Ground-, Rhinoceros and Island Iguanas

In the latter half of the 1990s I visited London Zoo with my wife one hot summer day. While walking around the zoo I was enthralled by the appearance of a prehistoric-looking creature about 6ft/2m long with a small horn on its nose and what appeared to be heavy jowls, voraciously tearing at grass with its jaws in an outdoor enclosure. The Rhinoceros Iguana was one of the sights that first drew this author into the world of herpetology.

Boulenger gives the characteristics of the genus as follows: tympanum distinct; body compressed; dorsal crest; dorsal scales small; enlarged scales on snout; small gular pouch and feeble transverse gular fold; digits compressed, with keeled lamellae inferiorly; long series of femoral pores; tail long, compressed; lateral teeth tricuspid; pterygoid teeth; small sternal fontanelle; single poststernal rib.

While uncommon in captivity compared to the Green Iguana Iguana iguana, the Rock Iguanas lack none of the charisma of their better-known relative. These hefty iguanas are found throughout the Caribbean and are instantly recognisable by their bulky form, the horns on the end of their snouts and in particular their heavy jowls. Despite their formidable appearance they are in fact largely herbivorous.

Regrettably the existence of some of the subspecies of this group has been considerably threatened by human activity. As usual the impact of man's fellow travellers, in particular goats, rats and dogs, was particularly heavy on the smaller island populations, the goats stripping much of the vegetation and the rats and dogs either harassing the iguanas or eating their eggs. To exacerbate matters, the large size of the lizards made them candidates for being hunted for meat. Fortunately this state of affairs has now been recognised as deplorable, and action has been taken to conserve those subspecies which are in extreme danger, although the outcome is by no means certain. Zoos are also working with some species, albeit with varying degrees of success.

According to Bosch and Werning, surprising little is known of the biology of the Cyclura. However, of great interest to herpetologists is their social behaviour, which is untypical of lizards in that the iguanas come together in large groups and interact socially. For this reason Bosch and Werning urge that the keeping of isolated individuals should be avoided, since these animals obviously require some degree of contact with their own kind. Since several individuals would obviously require a very large terrarium space - not so much a terrarium, in fact, but in effect a room of their own - this puts the keeping of Cyclura beyond the reach of all but the most wealthy and dedicated, certainly in northern Europe. Keepers in places such as Spain or Florida would have the advantage of being able to keep their captives outside for at least some of the year. It should be pointed out that most if not all of the species listed below are listed on CITES, which requires legal paperwork and hence some expense. It is to be hoped that dedicated breeding projects with reference to a proper studbook will ease the pressure on at least some of these species in years to come.

NOTES: "Hispaniola" here refers to Haiti and Western Dominica. Unless otherwise stated, all islands are in the Caribbean region. The notes section for each species will be completed as soon as we can get some further information.

Bibliography

See also Index of Iguanid Related Articles for articles on Cyclura in the wild and in captivity.

Links

International Iguana Foundation is a non-profit organisation working for conservation and the raising of public awareness. It appears to deal mainly with Iguana and Cyclura species.

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