The dolphin's exquisitely sensitive sonar has long captured the imagination of Navy scientists. Dolphins can pick out the most subtle features of submerged objects. In tests, blindfolded dolphins have been able to locate vitamin pills on the bottom of a tank, distinguish between identical sheets of aluminum and copper, and detect a stainless steel sphere only 7.5cm (3in) in diameter from a distance of 114m (370ft).

'The Navy would love to be able to do inside a destroyer what a dolphin can do in its head,' says former trainer Blair Irvine. 'A dolphin can probably tell if there's a submarine down there. The hard part is for humans to take that grey bulb with a fin on it and turn it into a black box.'

Lately Naval research into dolphin echolocation has escalated as current military strategy emphasizes the detection and destruction of long-range strategic nuclear missiles like Trident II, based on submarines. US Navy admirals believe that destruction of the Soviet fleet will be the curcial element in deciding the outcome of a global war and that dolphins can help solve their most critical problem of locating enemy submarines.

The Navy also wants to know which sounds interfere with the animal's echolocation ability, in order to develop a sonar jamming device to counter enemy-deployed dolphins.

In addition, the US Navy is studying the sonar capabilities of the beluga. These white-skinned whales are of particular interest because they inhabit the polar waters where many of the US and Soviet nuclear-capable submarine fleets patrol.

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