By Richard Black
Environment correspondent, BBC News
Scientists have made what they believe to be the first sighting of an adult white orca, or killer whale.
The adult male, which they have nicknamed Iceberg, was spotted off the coast of Kamchatka in eastern Russia.
It appears to be healthy and leading a normal life in its pod.
White whales of various species are occasionally seen; but the only known white orcas have been young, including one with a rare genetic condition that died in a Canadian aquarium in 1972.
The sightings were made during a research cruise off Kamchatka by a group of Russian scientists and students, co-led by Erich Hoyt, the long-time orca scientist, conservationist and author who is now a senior research fellow with the Whale and Dolphin Conservation Society (WDCS).