Today, the U.S. Navy Marine Mammal Program, based in San Diego, trains bottlenosed dolphins and California sea lions to protect ships and harbors. Sea lions help retrieve equipment from the ocean floor, dolphins locate underwater mines and both species detect unauthorized swimmers. Animals in the program have also helped researchers understand dolphin echolocation, assess the impacts of human-generated noise on wildlife and more. Current projects are testing whether it’s possible to judge dolphins’ health based on their whistles and whether a video game system can provide Navy sea lions with cognitive enrichment.