cetacean "smiles" are fixed, the extra movement afforded by the beluga's unfused cervical vertebrae allows a greater range of apparent expression. 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. Aquariums have tried housing other species of whales in captivity. The success of belugas turned attention to maintaining their relative, the narwhal, in captivity. However, in repeated attempts in the 1960s and 1970s, all narwhals kept in captivity died within months. A pair of pygmy right whales were retained in an enclosed area (with nets); they were eventually released in South Africa. There was one attempt to keep a stranded Sowerby's beaked whale calf in captivity; the calf rammed into the tank wall, breaking its rostrum, which resulted in death. It was thought that Sowerby's beaked whale evolved to swim fast in a straight line, and a tank was not big enough. There have been attempts to keep baleen whales in captivity. There were three attempts to keep grey whales in captivity. Gigi was a grey whale calf that died in transport. Gigi II was another grey whale calf that was captured in the Ojo de Liebre Lagoon, and was transported to SeaWorld. The calf was a popular attraction, and behaved normally, despite being separated from his mother. A year later, the whale grew too big to keep in captivity and was released; it was the first of two grey whales, the other being another grey whale calf named JJ, to successfully be kept in captivity. There were three attempts to keep minke whales in captivity in Japan. They were kept in a tidal pool with a sea-gate at the Izu Mito Sea Paradise. Another, unsuccessful, attempt was made by the U.S. One stranded humpback whale calf was kept in captivity for rehabilitation, but died days later. See also List of individual cetaceans Whaling in Japan References Bibliography