Animals have a long history of working in the military. Of course horses and dogs come to mind, but dolphins?
Since WWII, undersea mines are still damaging and sinking more ships than from all other causes. The Navy has been training Bottlenose dolphins since the 1960's to help the Navy find the bombs.
The dolphins have such a friendly, playful nature towards people, and they are rewarded with fish.This makes a good combination for training them. Using their sophisticated sonar ability (sense of hearing) the dolphins are able to pick out suspicious, metal objects from far away. The dolphin returns and pokes a ball with his nose, then he takes a buoy out to the suspicious area. The bomb is then disarmed by navy personnel.
What makes dolphins so perfect for this job is their sonar ability. They can tell the difference between something naturally there verses man-made and find objects in murky water. Human technology hasn't come close to replicating it.