Dolphin training, Navy Marine Mammal Program, San Diego, USA. Underwater photograph of a bottlenose dolphin (Tursiops truncatus) holding a bite-plate in its mouth. The bite-plate can contain surveillance equipment or be used to hook a tethered line onto an underwater object. US Navy dolphins are trained to detect underwater mines, deliver equipment to divers, locate lost objects and guard against intruders. Dolphins are highly intelligent animals and proficient swimmers, able to use echolocation to sense their surroundings. The NMMP also trains California sea lions, killer whales and beluga whales.