Dolphin Whistles Work Like Names—And Maybe Like Secret Codes

Scientists have known for a while that dolphins each have a signature whistle that acts like a name. But new research suggests those names could be carrying hidden messages—and we’re only beginning to understand how.

In a recent study published in The Journal of the Acoustical Society of America, researchers tracked Indo-Pacific bottlenose dolphins off the coast of Brisbane, comparing recent recordings to ones collected 15 years earlier. They found each dolphin’s whistle stayed remarkably consistent over time—but not perfectly identical. Those tiny, purposeful changes may carry hidden meaning.

Instead of repeating a whistle on autopilot, dolphins make subtle tweaks. These changes could reflect shifts in emotion, social context, or other unspoken signals. The whistle holds steady enough to confirm identity but loose enough to say more.

Dolphins Give Themselves Names That Could Hide Secret Information

Think of it like a face. Your features tell people who you are, but your expressions tell them what you’re feeling. Dolphins might be doing something similar with sound.

The study also found that male dolphins altered their signature whistles more than females—possibly due to different social roles. And in some cases, several dolphins appeared to share a variation of the same whistle, which researchers say could point to a shared group identity or bond.

None of this is casual. Up to 30% of dolphin chatter in social settings involves these signature whistles. And those aren’t one-note greetings—they’re social tools, refined and used with intention, capable of carrying emotional weight or signaling subtle shifts in dynamic.

All of this highlights the massive role sound plays in a dolphin’s life—and what’s at stake when the ocean gets loud. Constant noise from ships, sonar, and drilling could mean dolphins start losing track of who’s who. No names. No cues. No connection.

One researcher compared it to trying to spot someone you know in a crowd through fogged glass. You might still get around. But the faces start slipping away.

These whistles mean a lot to these beautiful creatures. Dolphins rely on these sounds to stay connected, to belong, to hold onto each other. But human noise is getting in the way.