Navy dolphins discovered a rare torpedo off the coast of California, one dating back to the late 1800s and the early days of undersea warfare.
The bottlenose dolphins that made the discovery had been trained by the Navy to search for dangerous objects under the water, things like mines that sometimes go undetected by the military's expensive technology.
"Dolphins naturally possess the most sophisticated sonar known to man," said Braden Duryee of the Space and Naval Warfare Systems Center Pacific.
The rare torpedo found by the Navy dolphins was known as the Howell torpedo, considered a breakthrough piece of weaponry at the time it was debuted. It was developed by the United States as it was building up its Navy, the first to be able to follow a track without leaving a wake, Navy officials said.
The Howell found was one of just 50 made between 1870 and 1889 before a newer and more effective model was created. There had been only one known Howell torpedo remaining, which is being displayed at the Naval Undersea Museum.
"Considering it was made before electricity was provided to U.S. households, it was pretty sophisticated for its time," said Christian Harris, operations supervisor for the biosciences division at the Systems Center Pacific.
The Navy compares its dolphins to security patrol dogs or those used to sniff for bombs or drugs.
"But just as the dog's keen sense of smell makes it ideal for detecting land mines, the U.S. Navy has found that the biological sonar of dolphins, called echolocation, makes them uniquely effective at locating sea mines so they can be avoided or removed," Navy officials said. "Other marine mammals like the California sea lion also have demonstrated the ability to mark and retrieve objects for the Navy in the ocean."
The program to train dolphins has been a major undertaking for the Navy since the 1960s. The Navy dolphins that found the rare torpedo are known for excellent diving capabilities and its biosonar system so sophisticated that scientists don't fully understand how it works.