Bottlenose dolphins remember each other’s signature whistles for more than 20 years – the longest social memory ever observed in an animal
said study author Jason Bruck of the University of Chicago’s Institute for Mind and Biology. He worked with 43 captive dolphins at six zoos/aquariums collecting whistle recordings. Bruck played dolphins the recordings of signature whistles from those they had once shared a tank with, as well as the calls of complete strangers. Dolphins got bored quickly listening to signature whistles from dolphins they don’t know, he said. But familiar calls often elicited an immediate response. Long-term social memory may help animals assess threats and opportunities for hunting alliances while preventing inbreeding.