U.S. forces in Iraq are using specially trained dolphins to help look for anti-ship mines in the waters off the key southern port of Umm Qasr. But it's not the first time such creatures have been used by the military.

The U.S. military has used intelligent sea creatures for three decades, including sea lions brought to the Persian Gulf to guard against attack by providing early warning of enemy saboteurs. Many sea lions have been trained to come to the surface to signal an intruder.

For the U.S.-led war in Iraq, having dolphins locate the mines would make it easier for troops to clear them. That would make it safer for military and humanitarian supplies to be delivered to Umm Qasr or another port city.