A team of Russian scientists has spotted an all-white mature male killer orca known as the Iceberg in the North Pacific, east of the Kamchatka Peninsula near the Commander Islands.

The researchers from the universities of Moscow and Saint Petersburg spotted the two-metre (about six feet) dorsal fin break the surface in August 2010. This is the first time that a mature orca has been seen by scientists.

The killer whale is believed to have been living in a family unit, also called a pod, with 12 other relatives. Two other white orcas are known to be there in the waters where the Iceberg was spotted, but they are said to be young, reported BBC.

"We've seen another two white orcas in Russia but they've been young, whereas this is the first time we've seen a mature adult," Erich Hoyt, Co-Director of Far East Russia Orca Project (FEROP) told BBC News.

"It has the full two-metre-high dorsal fin of a mature male, which means it's at least 16 years old - in fact the fin is somewhat ragged, so it might be a bit older," he added.

"Iceberg seems to be fully socialised; we know that these fish-eating orcas stay with their mothers for life, and as far as we can see he's right behind his mother with presumably his brothers next to him," Dr Hoyt told BBC.

AFP reports that the scientists are hoping to find out if Iceberg's white colour is due to albino, a genetic condition that leaves animals without melanin. It is caused by complete or partial absence of pigment in the skin, eyes or hair. Lack of melanin can cause eye defects in all vertebrates including humans. This becomes a big disadvantage for animals to hunt for food and protect themselves from predators.

There are some animals that are true albinos. Animals that do not have a single trace of melanin in their body are true albinos. Not all animals that are white are albinos. True albinos can also be identified with their eye colour. Such animals have either pink or red eyes but this eye colour is not common in humans.

Take a look at other animals that have albino conditions: