Bottlenose dolphins can call each other by "name" by mimicking distinctive acoustic patterns, a new study has found.
Earlier research had shown the marine mammals each develop a distinctive whistle that they use to identify themselves and broadcast their location to others.
When researchers at Scotland's University of St Andrews recorded the whistles of individual dolphins and played them back, they found the animals would react to hearing their unique whistles, similar to the way humans react when hearing their names called.
"Our results present the first case of naming in mammals, providing a clear parallel between dolphin and human communication," said marine biologist Vincent Janik.
The researchers followed pods of dolphins and recorded individual whistles. Using underwater speakers, they would then play back either the whistle of a dolphin from the pod, or one from an unfamiliar animal.
They found that dolphins did not react to the unfamiliar sounds, but individual members would respond when hearing their own sound, or "name," played, and send that same whistle back.
"Bottlenose dolphins therefore appear to be unique as nonhuman mammals to use learned signals as individually specific labels for different social companions," the study concludes.
The results are published this week in the journal Proceedings of the National Academy of Sciences.