They may not call each other "Flipper," but dolphins do have names. A new study by biologist Stephanie King of Scotland's University of St. Andrews and colleagues revealed that dolphins call each other by their names:
... King and Janik’s team analyzed recordings made over several decades by the Sarasota Dolphin Research Program, a Florida-based monitoring project in which pairs of dolphins are captured and held in separate nets for a few hours as researchers photograph and study them.
During the captures, the dolphins can’t see each other, but can hear each other and continue to communicate. In their analysis, King and Janik showed that some of the communications are copies of captured compatriots’ signature whistles — and, crucially, that the dolphins most likely to make these were mothers and calves or closely allied males.
They seemed to be using the whistles to keep in touch with the dolphins they knew best, just as two friends might if suddenly and unexpectedly separated while walking down a street. Moreover, copying wasn’t exact, but involved modulations at the beginning and end of each call, perhaps allowing dolphins to communicate additional information, such as the copier’s own identity.
Brandon Keim of Wired has the story: Link