crested gecko /(Rhacodactylus ciliatus)

The New Caledonian Crested Gecko, Guichenot's Giant Gecko or Eyelash Gecko (Rhacodactylus ciliatus), is a species of gecko native to southern New Caledonia. This species was thought extinct until it was rediscovered in 1994. Along with several other Rhacodactylus species, it is being considered for protected status by the

Convention on the International Trade in Endangered Species of Wild Flora Fauna. The species was first described in 1866 as Correlophus ciliatus by the French zoologist Alphone Guichenot in an article entitled "Notice sur un nouveau genre de sauriens de la famille des geckotiens du Muséum de Paris" ("Notes on a new species of lizard in the gecko family") in the Mémoires de la Société Scientifique Naturelle de Chérbourg.

Physical description

The New Caledonian Crested Gecko has hair-like projections found above the eyes, resembling eyelashes. It has a wedge shaped head with a crest that runs from each eye to the tail. The toes and the tip of the tail are covered in small hairs called setae. Each seta is divided into hundreds of smaller (approximately 200 nanometres in diameter) hairs called spatulae. It is believed these structures exploit the weak van der Waals force to help the gecko climb on most solid surfaces. The toes have small claws which aid in climbing surfaces to which their toes cannot cling.

The New Caledonian Crested Gecko has many naturally occurring color groups, some of which include: gray, brown, red, orange and yellow of various shades. They have variable markings, which include: spots, straight stripes and tiger-like stripes. The markings and coloration are not geographic indicators; offspring of the same clutch may display differing coloration and markings. The colors are brighter and more prominent at night.

The New Caledonian Crested Gecko has distinct structural morphs in head size and crest abundancy. Geckos with a head length less than 1.3 times its width are considered "crowned" Crested Geckos. They can vary in the amount and size of the crests; some have crests that extend to the base of the tail and some lack crests on one side of their body.

Geographic distribution

The Crested Gecko is endemic to South Province, New Caledonia . There are three disjunct populations, one found on the Isle of Pines and surrounding islets, and there are two on the main island of Grande Terre. One population is around the Blue River, which is a protected provincial park, and the other is further north, just south of Mount Dzumac.

Ecology and behavior

The New Caledonian Crested Gecko has no eyelids; a transparent scale, or spectacle, keeps its eyes moist and it uses its tongue to clear away debris. Like all Rhacodactylus geckos, it has webbing on its legs and digits. They are a mostly arboreal species, preferring to inhabit the canopy of the New Caledonian rainforests. They are primarily nocturnal, and will generally spend the daylight hours sleeping in a secure hiding place close to, or on the ground.

The New Caledonian Crested Gecko, unlike the closely related New Caledonian Bumpy Gecko (Rhacodactylus auriculatus), will not regrow its tail once lost. The cells around the base of the tail are brittle, allowing the tail to break away when threatened or caught by a predator. The capillaries to the tail will close almost instantly so there is little to no bloods loss. The tails will move independent of the body for 2-5 minutes. The loss of their tail is not problematic, and most adults in the wild do not have their tails.

This species is an omnivore, eating a variety of insects and fruit.

Captive care

Though the export of wild New Caledonian Crested Geckos is prohibited, biologists exported several specimens for breeding and study before the practice was prohibited. From these specimens, different breeding lines were established both in Europe and the United States. The Crested Gecko is now one of the most widely kept and bred species of gecko in the world.

These geckos can be very long lived. While they have not been kept in captivity long enough for a definitive life span determination, they are thought to live for 20-25 years.

Breeding

Little is known about the wild reproductive behavior of Crested Geckos, but in captivity they breed readily, with the female laying two eggs which hatch 60-90 days after they are laid. Eggs are generally laid at four week intervals as long as the fat and calsium reserves of the female are still at healthy levels. Crested Geckos have a small sac for calcium in their mouth. If an egg laying female does not have enough calcium her sac will be depleted, and she can suffer from calcium deficiency. This can lead to lethargy, lack of appetite, and even death.

There is controversy over whether heat plays a role in determining the sex of the embryo, as it can with other gecko species, but it would appear there is no correlation. Newly hatched Crested Geckos will generally not eat until after they shed their skin for the first time. Instead, they use the remains of their yolk sack for nutrition.