The Worlds Largest Gecko

The largest known gecko is found in the genus Rhacodactylus.   Rhacodactylus leachianus, also known as the giant gecko can reach over 15 inches and weigh around one pound.  Giant geckos tend to have a smaller tail compared to the body size, with 3/4ths of the gecko is head and body (Black). 

There are 2 subspecies of giant geckos, one found on Grande Terre (Rhacodactylus leachianus leachianus), and the other found on Isle of Pines (Rhacodactylus leachianus henkeli).  Due to them being in isolated areas on the islands the genetics gave them seperate color variations and one has a longer tail than the other (Black).  Dividing them into seprate species.  Both of these geckos do thrive in rainforest on the islands. 

Giant geckos are also known for their communication with one another and also as defensive mechanism to scary the predator.  They will make rapid clucking noises, whistling noises and sometimes growling noises (Black). 

Black, Adam. Crested geckos. Neptune City: T.F.H. Publications, 2005. Print

Pakinjak. 11/02/00. 2000. Photograph web. 9 May 2011. http://media.photobucket.com/image/leachianus/pakinjak/Leachianus%20DM100/DSC_0014.jpg?o=91

The Rough Living Rhacodactylus

Rhacodactylus auriculatus, commonly known as a gargoyle gecko, is a type of gecko found in a more dryer habitat than its relatives inhabiting rainforests.  These geckos come in different color variations than some of its relatives.  Ranging from white, light grey, light tan, pale yellow and a reddish orange (Black).  Gargoyle geckos are found on the southern end of Grand Terre island living is low scrubby vegetation and and small trees.  They have also been found in transition areas where natural and man-made clearings between rainforests are made (Black).  Some will even travel  and rest on the ground which is a huge difference in most geckos, due to them having the ability to climb on difficult surfaces to stay off the forest floor, away from predators. 

These geckos are noted for their aggressivness towards its mates. They often will lose their tails when breeding but have the ability to regenerate lost tails.  Females usually do the most damage to the males and will lose their tails and can inflict skin tears. 

I think that due to their aggressive behavior towards each other, this could be one of  the reason why they can regenerate their tails back and can heal fast.  What do you guys think?

Black, Adam. Crested Geckos. Neptune City: T.F.H. Publications, 2005. Print.

Moody, Chris. Jack the Gargoyle Gecko. 2008. Photograph. web 5 May 2011. http://www.flickr.com/photos/zpyder/3419042750/

Mossy Giant Gecko

The next species of the New Caledonia geckos, Rhacodactylus chahoua, the mossy giant gecko. Is a species of the geckos that are found on the Grand Terre island and Isle of Pines (Black).  They are noted for the patterns and colorations that they come in.  Shades of green, brown, rusty red, gray-green and a lichen color.  With a banded or blotted patterns to help blend in with the mosses, and lichens found of tree trunks and branches in the rainforests where they inhabit. 

This species of gecko can reach 10 inches and have a prehensile tail, like its relatives, however it does not lose its tail as easily.  The tail if dropped which rarely happens and will regenerate but not reach the normal size and stay smaller (Black). 

Like crested geckos, mossy giant geckos will lay multiple clutches of eggs throughout the breeding season.  These geckos will not bury the eggs but will lay a more calcified shelled egg (Black).  Making it more thick and harder to break.  It has been noted that the hatchlings have a tough time breaking through the harder shell of the egg.  Cause some to die inside the egg making the survival rate lower than other Rhacodactylus species.  

What do you guys think the benefit of having a harder shell and not burying them is then burying a soft shelled egg is? 

Black, Adam. Crested Gecko. Neptune City: T.F.H. Publications, 2005. Print

Liman, Alfred. Rhacodactylus chahoua. 2006. Photograph. web. 26 April 2011. <http://en.wikipedia.org/wiki/Rhacodactylus_chahoua>

A Newly Discovered Species.

Crested geckos, Rhacodactylus ciliatus, was only rediscovered in 1994.  Crested geckos were described by a french naturalist, Guichenot, in 1866 but did not follow up on the species for years.  The other species of Rhacodactylus were in the pet trade once herpetoculture picked up (Black).  Crested geckos were looked for over the years in the areas that Guichenot discovered them in 1866.  But none of the geckos were found. 

In 1994, the species was found on the Isle de Pines, then in the expedition led by Wilhelm Henkel and Robert Seipp, they discovered more crested geckos.   In another expedition with Philippe De Vosjoli and Frank Fast, they found more of these new species and brought them back legally to United States, where then smugglers started exported the species illegally (Black).  The geckos that were exported illegally are the origins of all the crested geckos found now in captivity.  Hobbyist and breeders now produce over 10,000 offspring every year!  Thats a lot of geckos!  In my opinion I think that if it wasnt for people exporting these geckos the geckos would not be as protected, and not as much would be known about crested geckos.  Due to the popularity of the species they have research done with them, and herpetologist specialize in just crested geckos and other Rhacodactylus species (Black). What do you guys think, do you think much would be known about these geckos if it wasnt for the illegal exportation of them. 

Photo By Author.

Black, Adam. Crested Gecko. Neptune City: T.F.H. Publications, 2005. Print

Tasting Their Enviroment For Rival Males.

Rhacodactylus not only use their tongue as a way of cleaning off their transparent fused eyelids, but also use their tongues as a way of tasting the pheromones for other males and potential mates (Black).  The male New Caledonian geckos like most male geckos do not get along with one another.  They will usually fight to death or until one retreats. 

The way these geckos can pick each up each others senses are by a organ found at the roof of their mouth called a Jacobson's organ. The geckos when venturing into a new terrain, will often lick the surface that they are climbing on, picking up any chemical traces of passing geckos looking for mates or making its territory (Black).  When their tongue licks a surface the chemicals on the surface are brought to the Jacobson's organ where it recognizes certain pheromones given off by other geckos.

Black, Adam. Crested Geckos. Neptune City: T.F.H. Publications, 2005. Print

Pedram :]. Windowlicker. 2010. Photograph web 19 April 2011. http://www.flickr.com/photos/multiphrenic/4258118386/

Eyes With No Eyelids.

One of the most notable physical appearance geckos of the genus Rhacodactylus are they large round eyes.  These eyes play a large role in their nocturnal lifestyle, in order to stay away from predatory birds in the past (Black).  This noternal eyes will dilate vertically as a slit when coming into contact with any excess amounts of light.  When in dark enviroments its eyes pupils will be more open and much wider.  Having large eyes gives them better motion detecting abilities in detecting prey and predators. 

Rhacodactylus leachianus close up of eye.



Along with having large eyes the entire genus of Rhacodactylus have no eye lids.  Their eye lids are fused together to form a transparent covering, called a ocular scale or eye caps (Black).  Commonly found in snakes, and other nocturnal geckos.  This fused scale acts as protection and a keeps the hydrated.  The tongue is used to keep the eyes clean of debris by licking the eyes. What do you guys think the reasoning nocturnal geckos like Rhacodactylus evolved to possess no eyelids? I think part of it has to deal with that they detect movement constantly weither is a predator or prey so never shutting your eyes gives you faster detecting abilities.

Black, Adam. Crested Gecko. Neptune City: T.F.H. Publications, 2005. Print.

Hague, Bradley. Gecko eye. 2010. Photograph. Web 16 April 2011. http://www.flickr.com/photos/bhague/5060361236/

A Fragile Island Gecko

The entire genus Rhacodactylus inhabit the small islands New Caledonia.  Located northeast of Australia, the small chain of islands put together only equal the size of New Jersey! (Black, 10).  New Caledonia lies north of the Tropic of Cancer giving it a humid tropical environment.  The main island, Grande Terre is a long narrow strip of mountain ranges through the middle and coastal plains.  On the south end of the main island lies another island, Ile des Pines, noted for its lush coniferous forests.  There are other smaller islands just off the coast of the 2 listed larger islands (Black, 10).

Due to human alterations of the habitat, these geckos are considered highly threatened.  Mining activities, agriculture and erosion has impacted the habitat by harming the original main forests.  Human introduced animals such as pigs, rats, dogs and cats have also impacted the fragile ecosystem and the geckos enviroment (Black, 25).  Rhacodactylus spend most of their time in the trees and brush on the islands.  One of the biggest killers of Rhacodactylus is an introduced fire ant, colonies can kill adults very easily.  Thanks to conservation of the threatened geckos, exportation of any species of Rhacodactylus is illegal.  Unless with proper permit they can be exported for scientific purposes and not for the pet trade (Black, 25).  These geckos need to be well protected to ensure that they do not become extinct due to another human impacted extiction...

Arndt, Daniel. Apollo the Crested Gecko. 2009. Photograph. Hillburst, Calgary, AB, CA. Web. 12 April 2011.
<http://www.flickr.com/photos/ubermoogle/3286276307/>

Black, Adam. Crested Geckos. Neptune City: T.F.H. Publications, 2005. Print

Brewbooks. Bay of Quinne New Caledonia. 2006. Photograph. Yate, Sud, NC. Web. 12 April 2011.
        <http://www.flickr.com/photos/brewbooks/238094371/in/photostream/>