The sighting of five sperm whales off Scotland's north west coast has been described as "extraordinary" by the marine conservation charity Sea Watch.
The sperm whales - one of the true giants of the oceans - were first seen by creel fishermen between Loch Torridon and South Rona.
They initially thought they were humpback whales and alerted boat operator Nick Davies from Hebridean Whale Cruises based at Gairloch who is involved in a project collecting cetacean (whale, dolphin and porpoise) data for Sea Watch.
He went out to the location, and when he arrived was astonished to recognise sperm whales diving together for food - the first time he has ever seen them.
Dr Peter Evans, director of Sea Watch, confirmed the sighting from Mr Davies' photographs, and said their presence could be a consequence of climate change.
Dr Evans told Aol Travel:"In past decades, most records of sperm whales in British waters have been of lone adult males around Scotland mainly off the Northern Isles and the Hebrides. Increasingly, however, adolescent males have occurred in our waters, sometimes in groups of 5-10 individuals.
"Sightings of groups of sperm whales have tended to occur mainly in summer so this winter sighting of a group is notable not just for the time of year but for its inshore location. The species normally lives in waters of 1000 metres or more depth, beyond the continental shelf edge. Here they have sought out the deepest area of NW Scotland – the Inner Sound."
Dr Evans added: "The increased occurrence of winter sightings in Scottish waters could be a reflection of climate change, with their main prey, squid, becoming more abundant locally in recent years, resulting in animals staying through the winter to feed rather than travelling into lower warmer latitudes."
Sperm whales are amongst the largest mammal species in the world. Adult males can weigh in at up to 45 tonnes - the iconic London Routemaster double decker bus weighs less than 8 tons.
Nick Davies said: "I was excited at the prospect of humpback whales, but never expected to see sperm whales.
"When I was about 8 to 9 miles away I could see their spouts - it looked like a flotilla of yachts and as I got nearer it was obvious from their flukes (tails), that they were sperm whales. There was one enormous animal and four smaller ones, and they were synchronised diving, going down for 30 minutes or so at a time.
"Fishermen have been telling me that for the past four or five years they have been seeing increasing amounts of squid in their nets, and it seems that this was perfect for the sperm whale."
According to Sea Watch's national database, there have been just 94 separate sightings in British waters since 1974, with the largest group on record being of 20 animals seen off Mousa in the Shetland Islands in 2007.
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