Currently there are two recognized subspecies of giant geckos; the Grande Terre giant gecko Rhacodactylus leachianus leachianus from the main island of New Caledonia, Grande Terre, and Henkel's giant gecko, Rhacodactylus leachianus henkeli from the Isle of Pines and surrounding islands to the south of Grande Terre. There are a number of subtle yet recognizable distinctions between the two subspecies, including scale, eye and tail differences. Keen observation also suggests that the two are socially and behaviorally different.
Giant geckos are, as the name implies, the largest described geckos in the world. They can reach a total length of 17 inches (43 centimeters) and can weigh over a pound (455 grams). Not only are they the biggest, but they are arguably the most vocal of all gecko species, and possibly of all lizard species as well. Rhacodactylus leachianus leachianus in particular has a tremendous vocal repertoire encompassing a variety of whistles, chirps, clucks, and growls. Giant geckos are the most colorific of the Rhacodactylus genus, and new morphs often exhibiting different colorations continue to emerge upon the herpetological scene. Though the lifespan of giant geckos is not known, they are another potentially long-lived species with individuals commonly living several decades.
Giant geckos are native to New Caledonia, more specifically the main island, Grande Terre and the adjacent Isle of Pines and some surrounding islands. Giant geckos are an arboreal species found in tropical forests often 18 or more feet off the ground. They inhabit large trees preferably with intercanopy contact and ample hollows. Like the other Rhacodactylus, giant geckos are nocturnal and spend the majority of the day wedged in hollows or niches within their favored habitat.
The habitat requirements of giant geckos are similar to those of other Rhacodactylus in the sense that they require ample vertical surfaces for climbing and resting. Given their large size however, giant geckos require larger housing than other Rhacodactylus. As with most arboreal species, vertical space is more important that horizontal space, so enclosures should be taller than they are wide. The single most important environmental factor for giant geckos is the accessibility of hollows. Flat or curled cork bark pieces provide both shelter and climbing surfaces. For adults, providing a number of hollows or hollow-like shelters will help reduce the chances of altercations between cage mates. Plants can embellish the appearance of an enclosure, but due to the giant geckos’ weight, only thick-trunked species should be used. As with chahoua, bromeliads, dracenas, snake plants (Sansevieria spp.), jade plants (Crassula argentes), ficus and umbrella plants (Schefflera) are good choices. Substrate can be newspaper, artificial grass carpet, or soil. Although providing a shallow (baby geckos can drown in deep dishes) water dish is usually adequate for giant geckos’ water needs, a low relative humidity can cause problems when giant geckos are shedding. In areas of low relative humidity, nightly misting of the enclosure can ensure that this does not become a problem.
Giant geckos, like the other Rhacodactylus species, are omnivorous lizards affording the hobbyist numerous choices for feeding. In the wild, they eat a variety of insects, fruits and nectars, and may also ingest bee pollen (presumably while seeking nectar). Until recently, Rhacodactylus were generally fed a pureed mix of fruit and/or meat supplemented with insects. Baby food has often been the puree of choice, but is limited in the nutrition area. There are several commercial diets that incorporate the Rhacodactylus' natural preferences for fruits and nectars and combine this with the necessary supplementation to ensure a complete nutritional diet. This being said, we believe that the geckos also benefit from the occasional feeding of crickets and/or superworms. Insects should be gut-loaded and dusted with an appropriate vitamin/mineral dust before feeding.
Giant geckos like most gecko species, are extraordinarily mobile and can be quick to jump, in some cases to their own peril. Since giant geckos are heavy bodied, these leaps can be particularly detrimental. In order to avoid injury to your gecko we suggest employing the hand to hand method of handling whenever you must handle your gecko. In this method the gecko is allowed to walk or climb across from one hand to another, by repeatedly placing the free hand in front of the gecko. Geckos handled in this way may calm down for brief periods. Sexually mature male giant geckos cannot be housed together as they will fight violently. Furthermore, the pairing of giant geckos can be arduous because potential pairs may not be compatible.
Another potential concern regarding giant geckos is the fact that they can be extraordinarily vocal--predominantly at night. While many will find this attribute appealing, it can be problematic for those living in close quarters or with neighbors nearby.