It’s true that crested geckos come in a wide variety of colors and patterns, most of these have been developed over time and multiple generations. The word “morph” comes from the term “polymorphism” which refers to the presence of multiple visually distinct forms of a single species. Morphs refer to the phenotypes of a given species; a “phenotype” is any observable characteristic of an organism. A very familiar example would be in Labrador retrievers: there are yellow, black, chocolate and red labs. Each color is a different phenotype.
But do crested geckos have morphs? Yes and no. They have many characteristics that can be inherited, and some types are often called a morph. Let’s discuss the differences between the crested gecko morphs and learn a little bit about genetics 101!
The genetics behind these phenotypes can be masked by a normal appearance. A familiar example of a recessive trait are albinos – the typical albino lab rat. If you breed an albino to another albino – all of the offspring will be albinos. If you breed an albino to the “normal” phenotype, the offspring will all LOOK like the normal parent. However, they will carry the gene for albino within them, within their “genotype”. We call them “hets” from heterozygous, meaning two different genes (to be technical, different alleles of the same genes). Bred to another het, they have a one in four chance of producing an albino, one in four of producing a genotypic AND phenotypic “normal”, and two in four of producing more hets. The albino and the genotypic normal are both homozygous compared to their heterozygous (“het”) siblings.
This is important to know, simply because these genetic rules do not seem to apply to crested geckos!
Crested Gecko Genetics
It’s hard to compare crested gecko genetics to other, more documented reptiles like leopard geckos and ball pythons because most of those morphs work on dominant and recessive genetics. Most of their designer morphs are homozygous and recessive, where the genes are carried in heterozygous forms. Crested geckos are “polygenic” (multiple genes controlling their phenotype) and less predictable because they aren’t considered het for any specific morph. It’s very “what you see is what you get”.
Simply put, you can get cool things to pop out randomly, but then you need to selectively breed that through multiple generations. More information on crested gecko genetics.
Think of crested gecko morphs as dog breeds – when you breed dogs from two different breeds together, you do not have a 25% chance of getting a full Labrador or Pug and 50% chance of getting Labs that carry Pug genetics. You get a litter of pups that take some characteristics from both parents and they can all look very different from each other!
The best advice is to pair pinstripes to pinstripes, dalmatians to dalmatians if you are looking to develop the morph or trait. If you feel you have a truly unique specimen or want to try an oddball pairing, know that you may not get what you are looking for. It may take several generations to refine a trait, and you’ll have lots and lots and lots of baby geckos along the way! Be prepared to house them yourself or re-home them. Many prefer to buy geckos with a traceable lineage for their morphs.
Crested Gecko Colors
Crested geckos have pigments that can range from very pale cream to very dark near-black; from buckskin and olive to reds and yellows. Vibrant colors are very desirable, as are high contrasts. The extremes of light and dark are also popular. Note that pure white “moonglows” as touted in some out of date books and magazines are as mythical as purple unicorns. What is often described as a moonglow is a fired down version of a red or yellow cream. Camera flashes can further wipe out the color.
Crested geckos probably lack the pigments to produce blue colors, unlike the more flashy Day Geckos (Phelsuma spp.) or the Electric Blue Gecko (Lygodactylus williamsi). So it is very unlikely to have blue, green or purple crested geckos, or any Rhacodactylus species. The closest we have are olive, which is really a combination of brown and yellow in the color spectrum, and so-called lavender, which is more of a slate grey.
Also note that a crested gecko’s color is described generally at the “fired up” stage – usually when a crested gecko is alert or stressed, which is why they are generally the most fired up when you open up their shipping container and look upon them for the first time. This is why many have issues with labeling crested geckos as “lavenders” since this is the common color for fired down dark geckos.
Many factors influence color expression, such as the environment, temperature and humidity, hormonal states, aggression and fear can produce different color shades within the same animal.
Crested geckos have color cells, called “chromatophores” that produce the colors (pigments) that we see. There are different types of chromatophores; they are named based on what color pigments they produce. Melanophores contain mostly melanin: eumelanin (brown/black) and pheomelanin (orange/rust red). Xanthophores produce yellows and reds. Another type of chromatophore is “iridophore” that produces a blue color not by pigmentation, but by the refraction of light off of compounds within the iridophore. Additionally, iridophores that reflect white are dubbed “leucophores”; if crested geckos do not have iridophores they likely do not have leucophores to produce the same white color found in some fish (guppies, for example).
Note that this is a very simplistic rundown on chromatophores and color pigment. Further, neither the color genes or the pigment composition of crested geckos or other Rhacodactylus have been studied and published. It is up to hobbyists to experiment and find the specific expressions of the color genes. We cannot “create” new color genes but we can alter the expression of pre-existing pigments.
Albino Crested Geckos
As of this writing, there are no living representations of an albino crested gecko. There was speculation of a hatchling albino, however it passed away a few days after hatching, so its status is undetermined.
What would one look like? For starters, we would have to drop the term “albino” because that refers to the color “white” and works well for mammals but not other vertebrates. Albinism is due to faulty melanin production and can vary in degree. Since crested geckos also produce red and yellow pigments (xanthin), a better term would be “amelanistic” for the lack of the black pigment melanin. There is also the term “hypomelanistic” which refers to a reduced amount of melanin, without an explanation as to why, such as a problem with the pigment cells as in albinism. Leucistic animals are those that lack ALL pigment in the body but retain color in the eyes, because early in development these structures diverge, allowing color development in the eyes.
To further add to the albino discussion, there are different types of albinos: T- and T+.
T- albinos don’t even make melanin or its precursors (the tyrosinase enzyme) and are generally very light. Either the gene is missing or switched off.
T+ albinism means the gene to make melanin (dark pigment) is present but there is a malfunction in the gene so the melanin is not fully expressed. This can result in brown shades and can contribute to hypomelanism.
This is a very simplistic explanation, as tyrosinase issues can come about as a result of mutations, deletions and polymorphic forms of the T producing gene. That’s why there are several “lines” of albino leopard geckos: different genes or different versions of the same genes can produce an albino.
So we have to look very closely at “odd” looking hypomelanistic geckos (lacking black/brown) to be be able to determine the first “albino” crested gecko. There is some debate whether this is even a possibility, as the odds are that an albino should have been expressed by now. Since most albinos are produced by recessive genes, it’s likely that we don’t have it in our captive bred Rhacs. It would possibly be a new mutation entirely.
Crested Gecko Morphs and Traits
Here is a quick morph guide to the different types of crested geckos and their associated traits.
Patternless Crested Geckos
A solid body of any color: buckskin, olive, chocolate, near-black, red, orange, yellow and shades between.
Patternless crested geckos are a good resource when breeding color into an already established line. Note that there are currently no fully white or black animals. Light yellow creams or unfired reds may be labeled “moonglows” but are not white. Dark, near-black crested geckos do exist but are usually not patternless or have white heads, tails, fringe, etc.
Bicolor crested geckos are generally patternless but with a slightly darker – sometimes lighter – color on their dorsal (top of head and back). Bi-color is usually seen in red, orange, olives and buckskins. Some bicolors have a hint of a pattern on the dorsal, but lack the cream of flame morphs (see below).
Tiger Crested Geckos
Tigers come in the same colors as above. Red tigers are somewhat rare due to the fact that when they fire up, the red pigment usually overrides the dark pattern tiger stripes. We have yet to see a red tiger beyond the juvenile stage (“hatchling red”) with dark, bold tiger stripes. Yellow tigers are the most striking due to their high contrast.
Moon Valley Reptiles is currently breeding yellow tiger crested geckos.
Extremely patterned tigers are also called “brindled”, “super tigers” and even “super brindles”. We love them all.
Flame Crested Geckos
Flames can be any color, but their dorsal is usually patterned with cream. Whiter creams are considered more desirable. The rest of the body is usually solid color but there can be minimal patterning, unlike harlequins (see below). The term “fire” is also valid for this morph.
Chevron crested geckos are flames that have step-stone like “v” shaped patterns on their backs. This terminology is less used today but is still a valid description of this dorsal pattern.
Tiger flames are possible, but generally rare. Often tiger stripes on juvenile flames disappear when they get older.
Harlequin Crested Geckos
Harlequins are highly-patterned flame crested geckos. A harlequin has a base color (usually red or near-black) with orange, yellow, or the highly fashionable cream. See color patterns, below, for popular color combinations on harleys.
Harlequins should have patterning along the limbs; if there is minimal patterning on the body it is technically considered a flame (see above).
Pinstripe Crested Geckos
Pinstripes are considered a single, independent trait whereas a morph is generally a group of traits or specific look like flame, tiger or harlequin, but they can be easily treated as a morph. People seek out pinstripes!
The classic pinstripe consists of raised, cream-colored scales along the outside of the dorsal. The rest of the back can have flame patterning, or it can be solid cream to match the pinstriping. A full pinstripe is more desirable than a partial pinstripe. If the pinstripe is broken and doesn’t form more than 80% of a full, it would be considered to have pin dashing and would not be termed pinstripe.
Most pinstripe crested geckos are flames or harlequin, but there are tiger pinstripes.
Variations on the classic pinstripe are reverse pinstripe and phantom pinstripe. A reverse pinstripe is a dark line underneath the dorsal scales where a classic pinstripe would be. This can be combined with a full classic pinstripe for a striking effect.
Lateral stripes refer to stripes along the sides of the gecko and is usually seen on a classic pinstripe.
Check out the Moon Valley Reptiles Dark Pinstripe project!
06-Mar-2012 20:59, Canon Canon EOS DIGITAL REBEL XSi, 5.6, 100.0mm, 0.005 sec, ISO 100
Crested gecko dalmatian spots are also considered an independent trait. Spots can vary in size and color, with black spots being the most common and red, green and even white spots appearing in certain individuals. An abundance of spots or exceptionally large spots can be described as a “super dalmatian” trait. Generally they need 100+ spots to qualify, but we do not have time to count spots!
Dalmatian spots can appear on any color or morph, but many keepers prefer dalmatians to be otherwise patternless and let the spots speak for themselves. A gecko without spots is considered “clean”.
Some combination of colors on harlequins and flames have specific names. These are not considered true “morphs” but people will refer to them as such.
Creamsicle crested geckos are typically orange flames. Orange harlequins with cream pattern also qualify. This term is sometimes applied to red and cream geckos, but this technically does not match the ice cream pop for which the combination is named.
Blonde crested geckos are typically dark flames with or without pinstripes. The dark base color contrasts quite nicely with the creamy dorsal. Dark harlequins with cream pattern also qualify.
Halloween crested geckos are harlequins with dark near-black and orange markings. The darker and more vibrant, the better! Neither black and gold nor black and creams qualify.
Tricolor crested geckos are harlequins with three colors. Generally an off-shoot of Halloween geckos with added cream, Tricolors are also available in red and yellow.
Moon Valley Reptiles really, really REALLY likes tricolor crested geckos!
Mocha and Cream
Mocha crested geckos are generally brownish to tan with cream markings. Not quite orange and not quite blonde! Very striking as tigers or reverse pinstripe flames.
Cream on Cream
The most holy of holies! Creamy goodness at its finest, a very rare color combination of a light-colored gecko with a cream dorsal. Sometimes seen as tiger flames.
Wild Type Crested Geckos
Most reptiles displaying “wild type” color and pattern are called “normals”. With Crested Geckos, there is no “normal” phenotype. In the wild, there are varying degrees of color and pattern. Even if we consider buckskins, brown or olive geckos “normal,” there is still a high degree of variability between them. Full pinstripes and extreme harlequins are perfect examples of improving upon the wild type via selective breeding in captivity.
There’s more to a high quality crested gecko than just color. We favor big, wide heads with bold crests on a solid body. Often these guys with their wide heads are called “crowned” but we don’t measure, we just pat their enormous noggins.
The latest theory on good structure comes from a long, cool incubation period. Genetics probably also plays a role but breeders have consistently found a correlation with their “winter babies” and good head structure.
Morphs vs Lines
Morphs are general descriptions on the physical characteristics of an animal, while the term “line” refers to a specific breeder’s offspring from selective breeding. This can still be important information when a breeder is well known for specific colors, traits, or other characteristics. However, it does become confusing when a line is used interchangeably with morph. AC Reptiles has very well known lines, such as “Marble” (Tiger, Flame, Dalmatian combo), “Harry” (furry scale trait) and “C2″ (cream base color with cream flame). Other breeders can produce these lines only if the pair both came from this stock. If you produce offspring from only one parent of this lineage, you should refer to them as “from XYZ lines”. If you produce similar looking but unrelated animals, you should NOT use the line name for ethical reasons.
Lines are sometimes referred to as designer morphs but this gets tricky when someone else also breeds similar animals, such as “cream on creams”, “citrus”, “neon”, etc. Many crested gecko breeders refrain from naming their lines in this manner to avoid confusing newcomers to the hobby.
For a very in-depth morph guide and lots of pictures, check out the Pangea Forum crested gecko morph guide!