Whales use 'sound map' of sea floor to navigate

WHALES navigate hundreds of miles using a mental map of the sea floor based on sound, scientists revealed yesterday.

They also use their songs to communicate across thousands of miles of ocean, new research has found. The discoveries have emerged from a study of whale song that is redefining what experts know about the giants of the deep.

Scientists used a network of ex-Cold War US Navy underwater microphones to listen to whales singing. Once the Sound Surveillance System (SOSUS) followed Soviet submarines in the North Atlantic. Now it is being employed to track blue, fin, humpback and minke whales.

The acoustic maps obtained from the recordings have given scientists a new insight into the world of the whale.

After listening to the songs for nine years, Dr Christopher Clark, from Cornell University in Ithaca, New York, realised he had been thinking about whales in the wrong timescale.

He said: "There is a time-delay in the water, and the response times for their communication are not the same as ours. Suddenly you realise that their behaviour is defined not by my scale, or any other whale researcher’s scale, but by a whale’s sense of scale - ocean basin-sized."

Week-long soundings at the US Navy’s Joint Maritime Facility at St Mawgan in Cornwall yielded thousands of acoustical tracks of different species of singing whales.

"We now have the ability to fully evaluate where they are and how long they sing for," said Clark. "We now have evidence that they are communicating with each other over thousands of miles of ocean. Singing is part of their social system and community."

Clark has tracked cohorts of humpback whales hundreds of miles apart moving together and watched the collective migration of species across vast expanses of ocean.