At least 25 whales have died after being stranded on the coast of Scotland, despite a major rescue operation, an animal welfare charity said Saturday. Nearly 70 pilot whales found themselves in shallow water at low tide, near the town of Kyle of Durness in north-western Scotland, dpa quoted the charity British Divers Marine Life Rescue (BDMLR) as saying. After the whales stranded, BDMLR managed to refloat and herd 44 of the mammals back into deeper water. Many of the whales had stranded on their sides, on top of each other and upside down, BDMLR said, adding that they were inhaling sand as a result. Whales have repeatedly become stranded along the Scottish and Irish coasts. Last year, 33 were found dead on the shore in the Irish county of Donegal. Researchers do not know why the animals swim so close to the shore. Animal activists think the whales, which are social animals, may be following sick whales who swim towards the coast to die. Another possibility is that the pilot whales are looking for places to rest, or are tempted into shallow waters in the search for squid, their preferred food.