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Killer whales, which are normally associated with the colder seas around the poles, are being found increasingly in
Already this year, the creatures, also known as orcas, have been recorded as far south as the Isles of Scilly, and in the
As well as eating fish, killer whales regularly hunt seals. Although attacks on humans are rare, experts warn against getting too close. Researchers from the
Andy Foote, from the
"That sort of sighting does seem to be on the increase," he said. "The killer whales shift their migration and distribution quite drastically. Fish like herring and mackerel seem to be doing pretty well at the moment, and it makes sense for the killer whales to follow them.
"So in areas where you haven't seen killer whales before, all of a sudden, you are starting to see them. You see more up north, but you do get them turning up further south."
Since the 1950s and 1960s, when
Mr Foote added: "Until now, very little has been known about them in British waters. They have been considered as being transient and occasional animals that just move through the area. People thought they were very infrequent visitors. The fact that we are seeing the same ones year after year after year shows that that is wrong.
"Already we have highlighted that we have populations which are resident here for long periods of time, coming back to the same place, year after year after year, while some seem to remain all year around. "Having seen them going after seals here, I certainly wouldn't recommend going too close."
Paul Harvey, from the Shetland Biological Records Centre, which is home to
"Something has gone on, since about the 1990s, when we first started to see more. We don't know how many pods we are dealing with. That is the value of the new research."
Killer whales – actually the largest species of dolphin – are known to occur in all the world's oceans. Those near the Shetland come close to shore to feast on seals.
"They are more exciting to see than other species," Mr Harvey added. "You see more of them out of the water and they are often doing something, like hunting seals. They are really spectacular."
Rob Lott, from the Whale and Dolphin Conservation Society, said: "The north of the country has become a stronghold but they do turn up all around the
As well as fish and seals, killer whales will also feed on sharks, including great whites, and even other species of whale, including the blue whale – the world's largest animal. They can swim at speeds of up to 30mph and hunt in packs. They grow up to 30ft long and live up to 35 years. Adults eat around four per cent of their body weight each day, while young whales eat up to ten per cent.
By the way I prefer to call them Orcas. V.S.