The Curse of Partial Albinism in The Yemen Chameleon

Chameleons are known to be masters of color change. They accomplish this by manipulating the concentration and distribution of color granules (black, yellow) in some specialized skin cells (melanocytes, xanthocytes) and by deforming guanine crystals in other cells in two layers, thus refracting light to reflect the desired colors and their combinations.  

Although the colors are highly variable and primarily used for intraspecific communication, threat display, and thermoregulation, they also indicate the age, sex, nutritional status, and health of individual animals. 

However, general color patterns are specific to individual species or populations. In contrast to many other reptiles (e.g., Eublepharis macularius, Pantherophis guttatus, Python regius, some Varanids, some Scincids, Pogona vitticeps, etc.), particularly in captivity, which are prone to developing color morphs and expressing color/pattern defects such as albinism, leucism, anerythrism, amelanism, and melanism, such genetic conditions are quite rare in chameleons. These conditions are often subjects of brutal inbreeding, which can span many generations and is inevitably accompanied by diminished genetic diversity due to exponentially decreasing heterozygosity. This results in various genetic diseases, deformities, organ failures, or metabolic issues of differing severity and nature. Breeders profiting from the public's preference for unusually colored animals may falsely claim it is merely line-breeding and typically do not disclose any genetic abnormalities that they may hide or euthanize. Nevertheless, the genomes of captive populations of many reptiles, maintained successfully for numerous generations in captivity, tend to deteriorate.

The following color aberrations have been tentatively documented in chameleons, some of which are unstable and revert to normality after a certain period, while others are permanent: 

• Red females and males of Trioceros jacksonii xantholopus 

• "True blue" Furcifer pardalis from Nosy Be (this may not be a good example, as it seems to be caused by nutritional issues in captivity that prevent the creation of yellow hues) 

• Bluish specimens of Trioceros quadricornis, Chamaeleo arabicus, C. calyptratus, Calumma osgaughnessyi, and Calumma parsonii (this observation reflects the same comment as above)

• Partial albinism reported three times in Furcifer pardalis (once by myself from Nosy Be, twice from feral populations in Florida) 

• Numerous color forms known from heavily inbred Chamaeleo calyptratus (some revert to normal during ontogeny, some persist, and some are inherited), such as:  

1. Lime yellow patternless 

2. Brown, no green 

3. Fully translucent 

4. Orange 

5. Brown midbody, no yellow stripes 

6. Blue (mentioned above) 

7. Translucent (commonly referred to in the USA) or piebald/pied (more common in Europe) 

 I first encountered the "translucent phenotype" of the Yemen Chameleon, Chamaeleo calyptratus, at a Daytona Reptile Show in 2012, and I prayed that the mutation would be lethal and would not spread further. However, while the genes and inbreeding weaken the animals, making them more prone to various disorders and resulting in behavioral deviations, they can also introduce low expression or latent traits that negatively impact the entire captive population. As these individuals continue to breed and inbreed, the white portions of their bodies increase, so fsr, rhe white is mostly rstricted to their hwads and limbs and tail.

This is not the blessing of the mighty Yemen Chameleon; it is its curse, driven by the proactive ignorance and greed of humans. Its genetic health is declining, and the captive population is becoming increasingly weak. What a pity and what a shame.