Clicking with Your Kin

How sperm whale sounds are like team uniforms.

n the moments before she dives, a sperm whale hangs over the dark abyss of the deep ocean and, with her voice, reaches out to her kin. She speaks in what are called codas: sets of clicks that, like the bundled taps of Morse code, each have some meaning to the whales. But before she plunges, this whale exchanges a special type of coda with her sisters and cousins, one that you won’t hear used the same way by any other clan.

Scientists call these special clicks identity codas: markers that the whales seem to use to signal what clan they belong to. If they work the way researchers think, it would suggest that the whales have some grasp of what anthropologists call “symbolic marking,” when a trait or object is used as a symbol of group membership. This is a hallmark of human culture.