Whale enthusiasts off the coast of Japan could hardly believe their eyes when they spotted two rare white orcas swimming together as part of the same group.
The orcas were spotted on a July 24 whale watching trip in the Kunashirskiy Strait, a 32-mile stretch of water between the northern islands of Hokkaido and Kunashir.
Mai, an employee of the Gojiraiwa-Kanko travel company, said one of the two was older with slightly darker skin, while the other was younger and had clearly visible scratches on his back.
She said the older whale was first seen about two years ago, but it’s the first time she’s seen the younger animal and the first time she’s seen them both together.
‘It was the best day ever. This is the first time two white orcas have been seen off the coast of Japan,” she said.
Japanese whale watchers were stunned over the weekend when they spotted two rare white orcas swimming off the coast of Hokkaido, one of the country’s most northerly islands.
The pair includes an older killer whale (right) that had been seen two years ago, and a younger killer whale (left) that had never been seen before
The pair are part of a pod that contains mostly normal-looking orcas, but these two are thought to carry a gene that partially removes pigment from their skin – making them look white
The white killer whales are not thought to be true albinos, meaning they have no skin pigment, and instead are thought to have leucism – an umbrella term for a range of conditions that partially remove pigment from their skin.
The pair are not “true” albino, which is caused by a genetic trait that means the affected animal doesn’t produce melanin at all — the substance that gives skin, hair, feathers and eyes their color.
True albinos will be completely white and have red eyes — a color given by the red blood in blood vessels usually hidden behind the iris that shines through them.
Instead, these two whales are believed to have leucism – an umbrella term that covers a range of conditions in which animals produce some melanin but either have noticeably whiter skin or skin with white patches.
That explains why the white patches that traditionally surround a killer whale’s chin and eyes are still visible on the two animals spotted near Japan, and why the eyes themselves are still dark.
It can also help explain the scars along the side of the younger animal – which is especially visible because the scar tissue appears to have healed to a darker shade compared to the surrounding white skin.
White orcas and whales were once so rare they were considered a myth, but are becoming more common, with scientists aware of at least five individuals living today.
Leucism may partly help explain why the younger dolphin has visible scars on its side – where the scar tissue contains more pigment than the rest of the skin, making the wounds hard to miss
White whales and killer whales are becoming more common — which scientists say may be due to declining numbers of animals, decreasing their genetic variation, meaning rare traits are more common
It is not known what effect the white color has on the affected orcas, although it does make them more visible which in turn could lead to less effective hunters and mean they attract more attention from rivals
One of the white killer whales swims alongside three other members of its pod, all of which have the typical white and black markings common to the species
It’s not clear exactly why they’re becoming more common, but scientists theorize it could be because of declining numbers of whales and a sign that the species is in trouble.
As the population of a species decreases, so does genetic variation, because the remaining animals have fewer potential mates to choose from.
Depending on the genes carried by those remaining individuals, it can accentuate some traits previously considered genetically rare.
That includes rare genetic disorders that hinder an animal’s ability to survive in the wild, threatening to accelerate the decline of the species.
While it’s not exactly known what effect leucism has on the lives of the orcas that inherit it, it does make them more visible — potentially hindering their ability to hunt and attracting unwanted attention from rivals.
However, the property is not always harmful. Kermode bears, for example, are traditionally black, but are increasingly born white thanks to a recessive gene.
Scientists have found that the trait leads them to catch more fish because salmon find it more difficult to spot them.