What is the distinctive individual whistle that a bottlenose dolphin develops called?

A distinctive individual whistle that a bottlenose dolphin develops is called a signature whistle.

Young bottlenose dolphins develop these whistles during their early lives. The sound functions somewhat like an acoustic identity label: other dolphins can recognize which individual is calling, even when the caller is out of sight. Dolphins may copy another dolphin’s signature whistle to address it, while also producing many other whistles, clicks and burst-pulsed sounds.

A signature whistle is not a human-style spoken name with a fixed dictionary meaning. It is better understood as a learned, individually distinctive vocal signal. Bottlenose dolphins are especially well studied because they are social, highly vocal and often observable in controlled research settings.

Their echolocation clicks serve a different purpose. Click trains help dolphins investigate objects and navigate, whereas whistles are commonly associated with social communication.