Since 1959, the U.S. Navy has trained dolphins and sea lions as teammates for our Sailors and Marines to help guard against underwater threats. The Navy initially wanted to study hydrodynamics in dolphins. In 1962, the dolphins' deep diving and echolocation capabilities, as well as their intelligence, sparked new interests from the Navy to advance naval ships and machinery. The program hired Dr. Sam Ridgway, a veterinarian who formerly served with the U.S. Air Force and is famously called the "father of marine mammal medicine." With Dr. Ridgway at the helm, the Navy’s marine mammals first became operational in 1970, and have traveled the world since, and been operational almost continuously since 9/11. The Navy's Marine Mammal Program has been homeported on Point Loma in San Diego, California since the late 1960s. Dr. Ridgway documented his years of experience during the early years of the program in the book, Dolphin Doctor, first published in 1987.

Today, the Navy relies on two species: the bottlenose dolphin (Tursiops truncatus) and California sea lion (Zalophus californianus). Both are known for their trainability and adaptability to a wide range of marine environments. They can easily dive hundreds of feet underwater, which humans can only do with very specialized equipment. Dolphins have the most sophisticated sonar known, a type of biosonar called echolocation. Both dolphins and sea lions have excellent low light vision and underwater directional hearing that allow them to detect and track undersea targets, even in dark or murky waters.