How do dolphins know who's whistling?

Each dolphin seems to have its very own whistle, called a signature whistle. No two sound quite the same. Scientists think dolphins use them to tell who's who, a bit like names. That helps a dolphin mum and her baby stay together.

How does a dolphin get its own whistle?

A young dolphin hears lots of whistles all around it. During its first year, it listens and slowly makes up a whistle of its own, based on the ones it hears. Once it's made, that whistle usually doesn't change much.

Why do dolphins click and whistle?

Wobble answers for ages 4–11, then goes 2 steps deeper each time a child asks why.

Wobble says

Dolphins send quick clicks out into the water. When a click hits a fish, it bounces back as an echo. Listening to those echoes helps a dolphin find its food. And whistles? Whistles help dolphins keep in touch with each other while they travel and feed.

For ages 4–7

Checked against Feature sound: bottlenose dolphin (Discovery of Sound in the Sea, University of Rhode Island)
How do dolphins know who's whistling?

Each dolphin seems to have its very own whistle, called a signature whistle. No two sound quite the same. Scientists think dolphins use them to tell who's who, a bit like names. That helps a dolphin mum and her baby stay together.

For ages 6–9

Checked against Specialized sounds in cetacean communication (Discovery of Sound in the Sea, University of Rhode Island)
How does a dolphin get its own whistle?

A young dolphin hears lots of whistles all around it. During its first year, it listens and slowly makes up a whistle of its own, based on the ones it hears. Once it's made, that whistle usually doesn't change much.

For ages 8–11

Checked against Specialized sounds in cetacean communication (Discovery of Sound in the Sea, University of Rhode Island)