This is the unedited version of my article for the Reptiles USA 2002 Annual. It is about 5500 words as compared to the edited version of about 3800 that they published in Reptiles USA.
The Crested gecko was introduced into the hobby in 1994, when it was brought into the limelight by its "rediscovery" (from a presumed extinction) in that year by two independent parties searching for herpetofauna in New Caledonia. Who could know, then, that this interesting species would in the matter of five years become one of the most popular species of geckos kept in captivity. Not since the Leopard Gecko, has there been a species with so many interesting characteristics and positive qualities. In many ways, the Crested Gecko is the perfect gecko for both the beginner and advanced Reptile hobbyist.
The Crested Gecko is a large, and very robust species of gecko that can reach a total length of about ten inches. It falls into the "wall climbing" category. Like many Geckos, It has adhesive toe pads that allow it to climb almost any surface, including glass. Rhacodactylus, however, also has a prehensile tail with an additional adhesive pad on the tip. This "extra limb", allows the Crested Gecko excellent maneuverability in its primary habitat of dense vegetation. They have also developed the ability to leap several feet, in an almost frog-like fashion. This skill allows The Crested Gecko quick access to that branch that is just out of reach.
They also have the ability to vocalize, and at night, sounds can be heard that are similar to growls, barks and clicks. These sounds seem to be the result of interaction between individuals, as specimens kept individually do not seem to call (casual observation).
Crested Geckos, as with the other members of Rhacodactylus, have shown to be a very long lived species. Only time will tell the average life expectancy of the Crested Gecko. At Sandfire Dragon Ranch, we have specimens that were acquired as adults in 1994. This would put their minimum age at the writing of this article at about 10 years. We have not yet had any Crested Geckos die from what would appear to be old age. These individuals, and their first generation offspring still have the look of animals in their prime, and the original females are still producing eggs on par with our young females. It is my estimation that Crested Geckos could easily live in excess of 20 years.
In Captivity, the Crested Gecko has proven to be amongst the hardiest of all Reptiles. They are recommended as one of the best species for a beginning hobbyist, yet they have many characteristics that will attract even the most advanced of keepers.
Until now, the Leopard Gecko was the obvious " best choice" for a first gecko, but the Crested Gecko has so much going for it that, as it becomes more available, it will give the Leopard Gecko some serious competition for this title.
There are many characteristics and qualities that make the Crested Gecko a standout for the novice hobbyist. Lets face it! The purchase of that first reptile for many is not just a one person decision. Many first-time keepers (think back to that first lizard you caught that gave you "herp fever") are still walking home from school and living with their parents. The biggest challenge of these beginning keepers is convincing their parents that a Gecko is a good idea, and that they are responsible enough to take care of it. More often than not, the need to return once a week to the pet store to buy crickets, and the thought of them getting loose (for the parent) in the house, is the reason why many first time hobbyist's trip to the pet store for a Gecko, often ends up with a trip home holding a fancy Goldfish.
The Crested Gecko (like all Rhacodactylus) in nature is an omnivorous species with a diet high in small soft fruit (non citrus), along with whatever invertebrates that happen within striking distance. In captivity, fresh soft fruits (and baby food) like Banana, Peach, and Apricot, are relished by Crested Geckos, as well as Crickets and other commercially available invertebrates.
Crested Geckos are very hardy in captivity, and appear to be very resistant to disease. They also rarely show symptoms of internal parasite complications (unlike Leopard Geckos). They do not require U.V. light exposure (with proper supplementation), and their preferred temperature range is in the mid 70's, meaning that in most homes, they will thrive at room temperature without supplemental heat. They are very resistant to cool temperatures, and can easily handle nighttime temperatures into the low 50's as long as they are able to warm up in the day. Crested Geckos are, however, sensitive to high temperatures and should always be kept below 85 degrees. Above this, they can become stressed, and exposure to high temperatures for prolonged periods of time can be lethal.
Sex determination in Crested Geckos is a fairly simple procedure. As the species reach the age of 4-6 months, they begin reaching sexual maturity, and the males develop obvious hemipenile bulges at the base of the tail.
The inexperienced keeper must use caution in judging the sex of juvenile Crested Geckos. Young individuals can appear as females, and almost overnight, develop the obvious hemepinile bulges characteristic of a male. Experienced keepers can manually evert the hemepine of young males to determine sex, but this procedure is not recommended for the beginning keeper.
A minimum cage size for an adult Crested Gecko should be about the equivalent of a 20 gallon tank. Good ventilation is important for Crested Geckos, and a screen top glass enclosure should be a minimum set up. Better yet, because Crested Geckos are primarily arboreal, is an all screen enclosure that is taller than it is long (for example 18w x 18d x 24h).
Because Crested Gecko's are nocturnal, they will spend most of the day in retreat, and require adequate hiding places. They prefer to hide near the top of the enclosure, so make sure to provide them hide spots in this part of the terrarium. These can be provided by pieces of pipe in a basic environment, or cork tubes in a naturalistic set up. In addition to good hide spots, living enclosures will benefit from dense vegetation to provide additional security for the Geckos. Bushy silk plants such as Pothos are an excellent addition to a non-living enclosure to provide this same security.
Substrate for these enclosures can vary considerably. In a basic enclosure, newspaper can be used, as well as various indoor/outdoor carpets. In a naturalistic enclosure, substrates such as coco bedding, peat, and potting soil can be used.
The Crested Gecko's polymorphic nature, and the possibility that the species is temperature sex dependent (incubation temperature determines sex) make it an excellent candidate for breeding by the advanced hobbyist as well as research biologist. We will focus here on the advanced hobbyist, and what could possibly be challenging to him/her with such an easy to keep species.
Its all in the Genes! The Crested Gecko's natural tendency to produce offspring with highly variable colors and patterns is quite unique. If you have been in the hobby even a short period of time, you will no doubt be familiar with the many color and pattern varieties of Leopard Geckos that are now sold in the trade.
Lets look at your average group of wild caught Leopard Geckos. If you took a sample of a thousand wild caught leopard geckos from a single location, you would notice that nearly all of them have similar and fairly drab coloration. If you take a similar sample of Crested Geckos, you will find an incredible variation in color, pattern, and even shape. Natural Leopard Geckos look very little like the "Designer" Leopard Gecko that we see in today's hobby. It has taken many years of selective breeding to produce today's "high end" Leopard gecko. And many its popular variations are based on mutations, not variations. The Albino, Blizzard, and Leucistic traits are all genetic mutations, and not "natural" variations. These mutations are produced by a combination of recessive genes that by the luck of the draw, are paired up to produce something new. These genetic mutations, are very rare, and a high dollar value is placed on them when they are introduced into the hobby. This value often reflects only the rarity of such mutations, and is usually not a reflection of beauty.
How many of you actually think a "blizzard lizard" is a beautiful gecko? It is (was) a rare mutation, which like the leucistic, and Albino, captured the hearts (and pocketbook) of many a collector. Variations on the other hand, are more "natural" traits that, when selected for, can be developed and brought from a nearly insignificant hint of color or pattern, to a prominent feature through generations of selective breeding. "High Yellow", and "Tangerine" are good examples of Leopard Gecko variations, and the "Sandfire®" bearded dragon is another example of line-bred traits.
Line breeding for both mutations and variations, are a challenging project for the advanced hobbyist, and are a good lesson in genetics. Care must be taken when selectively breeding for traits. Some traits are linked with others, and can produce deformities. Inbreeding can also often result in the appearance of health threatening mutations, and consistent out-breeding is necessary to introduce new genetics and insure the strength of future generations
Where am I going with all this, you might ask. What I am getting at, is that the Crested Gecko, in only a few generations, has shown us many interesting and beautiful variations. And early breeding results show that the offspring show an extremely high "response" to selective breeding.
On the other hand, genetic mutations (as described above) in Crested Geckos are yet to appear, and are a pure representative of "Lottery" like odds that will eventually appear as more numbers are reproduced in captivity. While hatching out an albino specimen can be exciting, it is not the reward that is the result of challenging selective breeding that takes generations to produce. The Crested Gecko is a breeder's "lump of clay", and the opportunity to select and create "signature" geckos has never before been such an opportunity. Think of looking at a plain old Carp, and knowing that with hard work and a little luck, a Show Koi is just around the corner.
There are several interesting characteristics in the Crested Gecko that will lend themselves well to selective breeding. Base color and pattern seem to be independent from each other at this point, but could prove to have specific links with future study. I will try in the following paragraphs, to define many of the traits that have been identified and selected for at this point, also attempt to remove some of the confusion in all of the different words breeders have been using to describe them, and attempt to simplify it by combining many of these names.
I will try and categorize the common colors the best I can. This is not an easy task because of a Crested Gecko's ability to change colors in an almost chameleon-like way. Each of these colors can appear in a unicolor morph, or bicolor morph, and can also be combined with a variety of patterns that will be described here.
The Brown Group:
Buckskin - A color that is various shades of brown, yellow/brown, or tan. Many call this the "normal" phase because it is the prominent color in nature. Buckskin paints a pretty good picture in most minds, and seems to be the popular description for these unspectacular specimens. These geckos can change from light to dark as influenced by their surroundings.
Olive - This morph can vary from very dark to almost pastel, and to the untrained eye, could sometimes be described as green. The color we know as olive in painting, is actually a combination of yellow and black, but contains no blue pigment as a true green (green is a combination of yellow and blue). That green tint you see in many other color morphs seems to be this olive color
Chocolate - These geckos are distinctly darker than the buckskin, and can appear almost black at times. They appear dark most of the time and do not seem to change color as much as the buckskin variety.
The Red Group:
Salmon - The salmon phase (often called peach and red) is a beautiful morph that is one of the more difficult colors to isolate. These geckos can appear absolutely stunning at times, but at others can become quite drab. There seems to be a lot of olive pigment in these specimens still, and only future breeding efforts will "clean up" and improve this trait.
Orange - This phase is distinct from the salmon phase. It has much more yellow pigment, and is usually brighter in general than the salmon. It tends to hold its color better, and as it changes, leans in the direction of the sulfer phase rather than the buckskin, as does the salmon.
Red - The "true red" coloration is an intense color that has evolved from selective breeding, and is quite an attractive morph. It tends to hold its color better than the Salmon, but can still change from an almost pastel to a bright "blood red". Most of the red Crested Geckos fall into the Salmon or Orange category if looked at closely. All three of these varieties can be equally impressive, and attractive to the collector.
Rust - As the name describes, this dark phase appears as a mix of the orange and chocolate phase, and has been referred to as "burnt orange" occasionally by breeders. They can appear very dark and almost chocolate like at times, but they always have that hint of orange that makes them distinct. They can also, at times, appear quite light, but always obtain that hint of chocolate.
The Yellow Group:
Yellow - These geckos appear quite bright in color, and rarely become dark and drab. They have very little brown or red pigment. They can be quite light at times, and are sometimes mistakenly identified as "pastel." (With the high amount of color changing ability, it is difficult to call any morphs of the crested gecko pastel).
Sulfur - This morph is what I would call a combination of yellow and rust. These geckos can be quite bright at times, and appear nearly orange in color. They never get as dark as a rust, and can often be difficult to differentiate from the orange morph.
Cream - This spectacular color is actually non-existent in a unicolor morph at this time, but in only a few generations will probably develop. This cream is the same bright creamy white that is part of the "fire" and "pinstripe" morphs. Selective breeding has shown this trait to show up more and more with each generation. This is an example of what can be created in the future.
The Brindle - Brindle is a term commonly used in mammals to describe a faint tiger stripe/marble pattern, and when we look at Crested Geckos today, this term is more appropriate. Maybe in the future we will see true tiger striping on a Crested Gecko, but for now, the term "brindle" seems the most descriptive and accurate. This pattern is typically most prominent in the flanks, but can be present in the legs and across the lateral rows of crests on top of the body.
The Dalmatian: This is exactly what it sounds like, a small black spots that can appear anywhere on the body. It would probably be more appropriate at this point to call them "pepper" phase, because we do not yet have a gecko that has as much black as a Dalmatian. But that time will soon come, and eventually, it will be possible to produce a solid black gecko from this small trait.
The Fire: This exciting pattern gives one the impression that the gecko has flickering flames on its back. It is usually prominent between the lateral rows on the geckos back, but now it is showing up on the feet and flank as well. The term fire is not descriptive of the actual color it contains, (a bright creamy white), but rather a unique random placement of this color that gives the appearance of a flickering flame. Many geckos also have this same color covering the top of the whole tail, but the color on the tail seems to be independent of the fire trait.
The Pinstripe: Also called "painted thigh" when present on the fringe of the hind legs, this is the same creamy white that is present on the Fire morph, this trait is independent of the fire trait, and the color is found in association with the enlarge scales along the sides of the body that make up the lateral rows, the fringes of the limbs, and even the scales around the mouth.
The Bicolor: This morph is a combination of usually light and dark colors, where the light color is restricted between the lateral crests, and the flanks are usually a dark color that can contain some brindle patterning.
The Harlequin: This is another trait name that has been imported from the mammal world, and it is a popular and good description for Crested Geckos. It is a combination of light and dark color morphs, that appear in a variety of blotches and patterns. Typically, the mid dorsal area (between the lateral crests) is primarily light in color, and the sides are dark and patterned. This is independent of the fire morph, but they are commonly found in combination.
I have made an attempt to describe the most common varieties here, and tried to set some kind of a standard, so that we are all on the same page when discussing these traits. These are my opinions only, but I have tried to take all that is out there and simplify it for future discussions. Some will disagree, but hopefully most will find these descriptions useful, and adopt them in discussion of Crested Gecko morphs. We can there by eliminate confusion, and be on the same page.
There are several physical traits such as head size, and crest size that will undoubtedly come into play in the future, and I am sure that I have forgotten some here. The point is that the "Sky is the Limit" when you think about the possible combinations of all these different traits that can challenge the selective breeder, and make your gecko an individual standout. Working with Crested Geckos can provide a keeper with an interesting and unique challenge, and be the platform for learning about genetics, business, and planning.
Crested Geckos have proven to be one of the most prolific of all geckos in captivity. The formula for breeding these Geckos is very simple, and really does not go much beyond the basic housing requirements previously discussed. A mature male that is kept with one or more mature females according to the previously mentioned requirements, will most likely reward the keeper with the production of eggs in the terrarium.
In nature, the transition from winter to spring "cycles" the geckos into breeding condition. In captivity, you can let the geckos naturally cycle if your room temperature varies with the seasons, and you have natural light from a window available. You can also stimulate mature Geckos to breed by manipulating ambient temperature and light in the enclosure. You also can choose to keep them at optimal temperatures throughout the year. However, under these conditions, care must be used in monitoring the females, because they can become calcium deficient if they lay too many eggs with insufficient supplementation. In the long run, we have found that not allowing a natural cooling off period can jeopardize the health of adult females, and do not recommend it.
If kept at optimal conditions, females are capable of producing up to 18 eggs per year, with the average being around 12.
The key issue once these requirements have been met, are the effective collection of eggs for incubation. Females will actively seek out a suitable nesting site for the deposition of their eggs, and a simple nest box usually does the trick.
After much trial and error, we have found that an open top nest box is the most effective. We have tried many nest box substrates, and found that moist coco bedding is a very good choice. We use a plastic shoebox for our container, but any like-size container should suffice. The substrate in the nest box should be kept moist, but not soggy, and in the breeding situation, should be checked for moisture and eggs on a daily basis, if possible.
In a simple, non-naturalistic enclosure, with no substrate, the female Crested Gecko will nearly always use this nest box for egg deposition. In an enclosure with live potted plants, and/or a deep substrate, the collection of eggs becomes more difficult. In these situations, a female will often find the substrate in the enclosure a more suitable spot than your nest box, and nothing you can do will change her mind. In this case, you will need to search the enclosure for eggs. Females will usually seek out a dark location, with an area of moist substrate, so this is a good place to begin your search. It has also been recorded that eggs laid in naturalistic enclosures that are deposited in an area of constant moisture, and favorable temperatures, can hatch without problems.
If collection and incubation of eggs are your goal, I would recommend a simple enclosure with little substrate and a nest box. But if you enjoy the benefits of a naturalistic enclosure, and are happy to collect a few good eggs now and then, and would be ecstatic to have a hatchling show up in your vivarium, this is a wonderful way to enjoy your Crested Geckos.
If you do happen to keep your Crested Geckos in a naturalistic enclosure, and are lucky enough to find a hatchling in the enclosure, remove it immediately, because it means that you have found it before the adults did. The adult Geckos are most likely to consider the hatchling a good source of fresh protein, and can quickly consume your newfound treasure.
Once collected, eggs should be incubated in a sealable type plastic container that has been perforated with a few ventilation holes. For a substrate we prefer Perlite, but Vermiculite is also used by many hobbyists. Both of these products can be found at most Home and Garden Centers, where they are used as soil additives. We mix our Perlite by weight with water. Our formula is one part water two parts Perlite.
Once laid, the eggs can be kept in an incubator, or at room temperature if the ambient temperature is within parameters. In the incubator, we recommend a temperature setting of between 77 and 81 degrees. Hatch rates above this temperature quickly decline. Eggs incubated below this range will have a good hatch rate down into the low 70's, but incubation duration increases dramatically. At room temperature, with mild daily temperature fluctuations, the hatch rate is also good. At Sandfire, our rooms fluctuate from nighttime lows in the low 70's to highs in the day that can approach 85 degrees.
The average incubation duration under these conditions is around 70 days, but this can vary considerably when temperatures exceed the recommended range.
Within the first days of hatching, the juveniles will shed and begin eating.
Like sized juveniles can be raised together without problems, but care must be used monitoring males raised together as they reach maturity to be sure that no injuries occur from aggression. Sexual maturity can be reached in less than one year with females, and as soon as six months with males.
There are currently six (6) recognized species and two (2) subspecies in the genus:
R. auriculatus (Gargoyle gecko) Bavay, 1869
R. chahoua (Bavay's giant gecko) Bavay, 1869
R. ciliatus (Crested gecko) Guichenot, 1866
R. leachianus leachianus (New Caledonian giant gecko) Cuvier, 1829
R. leachianus henkeli (Henkel's giant gecko) Seipp & Obst, 1994
R. sarasinorum (Roux's giant gecko) Roux, 1913
R. trachyrhynchus trachyrhynchus (Tough-snouted gecko) Bocage,1873
R. trachyrhynchus trachychycephalus (Lesser tough-snouted
Rhacodactylus are fascinating species, each with their own special characteristics. For the most part, they all require similar care, and it would be a natural progression for keepers to add these other species to their collections. So far, the availability of these other species has been limited, and you will have to source them directly from the breeders, or request them at your local reptile specialty store.
Crested Geckos are just now being produced on a commercial scale, and are available in reptile specialty stores as well as the larger pet store chains. Current retail prices (fall 2002) run from a low of around $50, to nearly $1000 for some of the exceptional colored and patterned specimens.
Crested Geckos have emerged as a Cinderella story in the reptile and amphibian hobby. They have proven to be one of the hardiest and most interesting of all geckos. We have only scratched the surface of the beautiful colors and patterns that will emerge as generations go by. The challenge for breeders to sort out these traits will guarantee a bright future for this species in captivity. Will the Crested Gecko become the Koi of the gecko world? Stay tuned...
The Vivarium Magazine articles
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