Even with the current advanced technology in high-tech sensors and underwater robotics, dolphins and sea lions keep on being the U.S. Navy's best defense against scuba diving terrorists. "They are better than anything we have ever made,'' said Mike Rothe, head of science for the Navy's marine mammal program, which trains marine mammals to guard military installations.

The program trains about 75 dolphins and 25 sea lions at Naval Base Point Loma in San Diego Harbor in tracking down terrorists and mines underwater.

The Navy intends to use up to 30 dolphins and sea lions to guard the waters of Washington state's Naval Base Kitsap-Bangor, harboring nuclear submarines, ships and laboratories.

Both types of marine mammals can detect mines and swimmers in murky waters.

The dolphins are known for their use of ultrasounds in detecting objects (like the bats, they really "see" with their ears). The dolphins can signal a mine or a swimmer with a flashing light.

Using their mouths, the sea lions transport a cable with a device that attaches onto a terrorist's leg, and the individual can be dragged up by sailors.

The sea mammal program began in the late 1950s and during the Cold War included up to 140 animals.

Dolphins were useful in the protection of a pier in the Vietnam War.

The last time the animals were deployed overseas was in 2003 in the Iraqi harbor of Umm Qasr and were of great use in detecting underwater mines and clearing the path for Marines to land. "Swimmers planting bombs pose a real threat," said Cmdr. Jon Wood, who participated to operations in Iraq with the mammals. "There were several cases of guerrillas laying charges on floating objects in Vietnam."

Towards 2000, Navy officials thought it was time for technology to replace the animals but that seems now to be far away, and dolphins and sea lions will be employed at least until 2012.

Animal rights activists warn that the dolphins and sea lions could be affected in the cold water in the Washington state and they could transmit diseases to the area's killer whales. "The dolphins are closely monitored for any signs of disease", ensured Dr. Stephanie Wong, a military veterinarian.