AUDIE CORNISH, HOST: It's no secret humans have an abiding fascination with dolphins. These marine mammals are cute and friendly. They're also smart and curious and have remarkably complex social lives. Well, a new study gives us one more reason to marvel at dolphins. As NPR's Rhitu Chatterjee reports, they have the longest known memory in animals.
RHITU CHATTERJEE, BYLINE: Scientists have known that dolphins recognize each other by the sound of their signature whistles.
JASON BRUCK: Those individually specific whistles that each dolphin generates before t
