BBC Earth reports that a few specially trained dolphins can now choose their favorite foods and make choices with a special echolocation computer system. <br /> <br />The Echo Location Visualization and Interface System, or ELVIS, projects different shapes on a special screen underwater that the dolphins can fire their biological sonar at. <br /> <br />The computer calculates the strength of the signal, which clearly indicates to the trainers which fish the dolphin wants for a snack.
