Notty the Military Dolphin
The United States military uses sea mammals — mainly bottlenose dolphins — to assist in a wide variety of tasks, such as locating underwater mines and alerting seamen and others when enemy swimmers are gliding around protected harbors. Dolphins make exceptional assistants because they are intelligent and trainable, swim fast and have sonar abilities that far outstrip what's available in modern technology [source: Bienaimé].
Notty, a female white-sided dolphin, was the U.S. Navy's first finned employee, added to its ranks in 1960. Initially, Navy officers were merely going to study Notty's biomechanics so they could create faster torpedoes. But as they learned from her, they realized she could be used in the field alongside humans.
While much of dolphins' military employment has come during peacetime, they did participate in the Vietnam War (five guarded an Army ammunition pier) and in the later stages of the Iran-Iraq War (protecting a ship in the Manama Harbor in Bahrain). They were even used to provide security in the waters off San Diego during the 1996 Republican National Convention. In 2015, the U.S. Navy reported it had 85 dolphins (and 50 sea lions) in its employ [source: Bienaimé].