Bottlenose dolphins have unique names for each other called signature whistles.

Researchers Vincent Janik and Stephanie King from the University of St Andrews studied wild bottlenose dolphins in 2013. They recorded individual whistles and played them back through underwater speakers. The dolphins only responded when they heard their own specific whistle. This proved that the sounds work as individual names rather than general noises.Dolphins develop these names as calves. A baby dolphin makes a whistle that sounds different from its mother to avoid confusion. About 90% of the whistles a dolphin makes are its own signature name. They use these sounds to stay together in large groups in the ocean.Data from the Sarasota Bay Dolphin Research Program in Florida shows dolphins remember these names for over 20 years. Dolphins sometimes mimic the whistle of a close friend to get that specific dolphin's attention. This behavior shows that dolphins have high social intelligence and the ability to learn complex sounds.Most animals use sounds to show they are angry or looking for a mate. Using specific labels for individuals is very rare in nature. This ability requires a large brain and the capacity for vocal learning. It puts dolphins in a small group of animals, including humans, that use names to communicate.