 Between 1960 and 1992 , the Navy carried out a program that included the study of marine mammals ' abilities with sonar , with the objective of improving the detection of underwater objects . A large number of belugas were used from 1975 on , the first being dolphins . The program also included training them to carry equipment and material to divers working underwater by holding cameras in their mouths to locate lost objects , survey ships and submarines , and underwater monitoring . A similar program was used by the Russian Navy during the Cold War , in which belugas were also trained for antimining operations in the Arctic . 
