California sea lions are a success story of 1972’s Marine Mammal Protection Act. In the late 1920s, no more than 1,500 sea lions were counted on the California coast.

(Watch a National Geographic video of the Galápagos.) They glued special recording devices onto the backs of 93 juvenile sea lions that ranged in age from 1 to 2 years old.

From groundbreaking research to the beauty of marine sanctuaries teeming with life, these images shine a spotlight on the ...