Gremlin dove deep into the water and quickly found what he was looking for: a sea mine on the ocean floor. He attached a clamp to the mine so that workers could safely pull it out of the water. Gremlin is a sea lion that was trained by the U.S. Navy to protect American sailors and ships from danger. Because sea lions are smart and able to swim fast, dive deep, and fit through narrow spaces, they can locate mines and capture enemies underwater more quickly than humans or machines can. In this book, young readers will meet the California sea lions that work with the U.S. Navy to patrol sea and coastal waters around the world. They'll also discover the history, training, and care of these brave working animals. Full-color photos and dramatic true tales capture the stories of these animals and their critical military missions.