Albino animals: pale rarities in a coloured world
Ghostly whales, snowy wallabies and whitewashed peacocks - albinism's rarity in the wild lends it mystique.
"He was white as wool", wrote reporter Jeremiah N Reynolds in 1839 describing Mocha Dick, an albino sperm whale killed off the coast of Chile in 1838. His true story of an epic battle with the white whale inspired Herman Melville's fictional 1851 classic novel about the hunt of a white whale, Moby Dick.
White is a rare colour in nature and it's not surprising the unusual pale hues found in people, animals and plants affected by albinism are romanticised in literature. The rare colouring is manifestation of a gene mutation that disrupts the production of melanin, which colours eyes, skin, hair, fur and leaves. Without this pigment animals or plants default to white or colourless states.
Not all white animals are albino
This doesn't mean, however, that all white or fair animals or people are albino. Polar bears, Kermode bears (spirit bears) and Scandinavians, for example, carry fair genes, but not gene mutations that inhibit colour. Some animals also suffer from different disorders that affect their pigmentation to a different extent.
Even within albinism, there are varying degrees of colouration, ranging from coppery through to very white. And so it's a common misnomer that all albinos have pink eyes; indeed some do, but some have blue and even hazel and brown eyes. Some plants are also only partially albino, producing either regular or random stripes or colour patchers. Other people and animals are only white at the warmest points on their bodies.
Oculocutaneous Albinism (OCA) for example is classified along a scale. "So classically OCA1a is super-duper, duper white; white as snow," explains Dr Shari Parker, a medical doctor with The Albinism Fellowship of Australia. "OCA1b has a temperature-sensitive variant and so the cooler the parts of the body the greater the pigmentation. So in people that means they might be a little bit darker towards the ends of their arms and legs. The eyelashes one of our members are white where they grow out and at their tips they're black."
This, in fact, is the mutation is that creates the highly valued colouration in Siamese cats, which are all albino. Breeders call it "point colouration". At birth Siamese kittens come out of their mother's warm womb all white. With exposure to air, the kitten's markings slowly darken in the body's coolest areas. This causes the tail, face, and paws to darken over time to the colour that would have expressed had it not been for the mutation.
The longer a cat with temperature-sensitive albinism is exposed to cold, the darker his markings will get. For this reason, many end up a solid blackish-brown. Although some Siamese cats have impaired vision, they are otherwise mostly functionally fine.
People with albinism
In humans about 1/17,000 people have albinism. However, Shari says roughly 1/70 people carry it unwittingly. This helps explain why it has persisted for so long.
"Because it's recessive the carriers of the gene are not naturally selected against," says Shari, who is herself albino, but whose parents do not have albinism.
Albinism also comes with some significant disadvantages, as the pigment in your eyes plays a big part in the formation of your eye muscles, retina, and optic nerve, and so many people affected by albinism struggle with significantly impaired vision. Skin cancer is also an issue, as pigment absorbs light and protects skin from melanomas.
Albino animals vulnerable in the wild
In the wild albino animals are much less likely to survive for a number of reasons. Being fair or white makes them vulnerable to predators, sunburn and cancer; they have a reduced ability to mate, so are likely to die before they get to pass on their genes.
Some amazing examples have survived these challenges, including Migaloo, an albino humpback whale frequently spotted off the Australian east coast during the yearly humpback whale migrations. Migaloo - an Aboriginal word meaning 'white fella' - is the world's only confirmed albino whale and is thought to be 25 years old. Two or three other white whales are known of, but spots on their skin suggest they may have a different disorder called leucism. Track sightings of Migaloo
Bruny Island off Tasmania's south-eastern coast has also nurtured a population of albino wallabies, where their sheltered island life and remote population has meant they've managed to carve out a niche for themselves. Across the country sightings of naturally occurring albinos are also periodically reported to newspapers. Everything from kookaburras to echidnas pop up regularly, but it's rare to see them survive to maturity in the wild.