But during two days in May 1996, Dr Frantzis observed something that he had never seen before a dozen beaked whales stranded as individuals, rather than a group, along a 40km (25 mile) stretch of coast.

ECONOMIST: Quiet, please. Whales navigating

Stephen Marsh, of BDMLR, told BBC Radio Scotland that it was not known why pilot whales had stranded overnight.

BBC: Royal Navy 'changes training' to avoid whales

Some training as part of Exercise Joint Warrior has been altered to avoid Portmahomack in Easter Ross where three long-finned pilot whales were stranded.

BBC: Royal Navy 'changes training' to avoid whales

It said many of the whales had stranded on their sides, on top of each other and upside down and were breathing in sand.

BBC: Pilot whales die after Highland beaching

The scientist said sinking stranded whales could be an alternative to cutting them up and incinerating the animals.

BBC: Scottish deep sea 'zombie worms' whale study suggested

Rescuers trying to save the pod said the whales had perished when they stranded at low tide.

BBC: Pilot whales die after Highland beaching

Fifteen whales have died and many others have become stranded at Kyle of Durness, on the north Highland coast.

BBC: Pilot whales die after Highland beaching