They are cream while others are cocoa; they are chalk while others are (exceptionally dark) cheese – these reptilian oddities are the albinos of the cold-blooded world. But how are albinos different from animals which are simply ‘white’, and does their condition cause them to perform differently in the great Darwinian game of life-and-death?
Image: Oliver Tupman
Put simply, albinism is the lack of any colour pigment, not the presence of white pigment. Certain enzymes critical for the formation of the pigment melanin in particular are absent in albinos, resulting in this rare condition. Melanin ordinarily defines the colour of an animal’s eyes, skin and fur. Scientists have identified the gene thought to be responsible for making this happen – the TYR gene. If the TYR gene is damaged, the animal will be born without the ability to reliably form melanin. Other side-effects of this process include pink or red eyes, as the lack of pigment allows the blood vessels behind them to be seen.
Image: Ryan E. Popline
Albinos are even less likely to occur in the animal world as they are among humans, which is partly what makes these alligators so rare. They, like albino humans, carry the recessive albinism gene. This means that both parents must carry the gene for the offspring to exhibit the trait. However, another effect of albinism being a recessive gene is that both parents may be carriers without actually exhibiting the trait themselves. This means that two ordinarily-coloured parents may give birth to a creamy-white albino offspring.