What are the individually distinctive calls of bottlenose dolphins called?

The individually distinctive calls of bottlenose dolphins are called signature whistles.

A signature whistle is a learned, frequency-modulated whistle associated with one dolphin’s identity. Other dolphins can recognize the whistle’s distinctive contour, much as humans use names or identifying voices. Researchers record these sounds with underwater hydrophones and analyze their frequency patterns.

Calves usually develop a signature whistle during their first year. The sound is influenced by the whistles they hear from nearby dolphins but generally remains individually distinctive. A dolphin’s signature whistle can remain stable for at least 12 years, and studies indicate that dolphins may remember another individual’s whistle for more than 20 years.

Signature whistles are not the same as echolocation clicks. Clicks help dolphins sense objects and navigate through echoes, while whistles are social signals used for identity, contact, mother–calf coordination, and group cohesion. Dolphins can even copy another dolphin’s signature whistle, apparently addressing that individual directly.