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What are sperm whales saying? Researchers find a complex 'alphabet'

AYESHA RASCOE, HOST:

Artificial intelligence is making big gains in understanding human language, but here's a challenge for machine learning - understand the language of whale. And an AI has accepted the challenge. In a new study, researchers used artificial intelligence to discover that sperm whale communication is way more complex than they previously thought. Lauren Sommer of NPR's climate desk has more.

LAUREN SOMMER, BYLINE: Sperm whales spend a lot of time in the dark. They dive thousands of feet down searching for deep sea squid.

SHANE GERO: These are places where sunlight never gets to. So sound is everything to sperm whales.

SOMMER: Shane Gero is a biologist with Project Ceti, which is trying to understand what sperm whales are saying. The whales live in tight-knit female-led family groups, he says, and they do a lot of communicating. But sperm whales don't sing. They make clicks.

GERO: And they make them in long exchanges, sometimes for over an hour.

SOMMER: Think boisterous family dinner.

GERO: It's not rude in sperm whale society to talk at the same time and overlap one another.

SOMMER: Gero says if you break up these exchanges, they're made of patterns of clicks called codas.

GERO: One that's really common in the Caribbean is the one plus one plus three coda, which sounds like this...

(SOUNDBITE OF CLICKS)

GERO: ...One plus one plus three.

SOMMER: Family groups can have dozens of codas like this. So Gero started working with Daniela Rus, who directs MIT's computer science and artificial intelligence laboratory. They analyzed more than 9,000 recordings of sperm whales from the Caribbean.

DANIELA RUS: It really turned out that sperm whale communication was indeed not random or simplistic, but rather structured.

SOMMER: Rus says machine learning technology allowed them to detect tiny differences. Sometimes the whales vary the tempo of the clicks very slightly. Sometimes they make the sequence longer. Sometimes they add an extra click.

RUS: And this was very interesting. We started wondering, is this extra click sort of like the end of a sentence or something else?

SOMMER: In their study in the journal Nature Communications, they found these variations aren't random.

RUS: They can be predicted by machine learning in the same way in which you might predict the sequence of syllables or the sequence of words in a sentence.

SOMMER: Rus says this shows that sperm whales have a big toolbox of sounds, ones that could possibly be combined to make meaning, the way humans recombine sounds and words.

RUS: This is challenging the current state of the art or the current beliefs about the animal world.

SOMMER: There is a long-running debate about whether animals have language the way humans do. Taylor Hersh is a researcher at Oregon State University who studies sperm whales. She says, while it's useful to compare it to human language, it could also limit how we understand it.

TAYLOR HERSH: Some of what they're doing may be totally different from our way of communicating and we're probably never going to be able to fully grasp those differences.

SOMMER: Figuring out what sperm whales are saying is, of course, a much harder task. Project Ceti is in the process of gathering more recordings in the hope that artificial intelligence could help tease out what sperm whales are talking about.

Lauren Sommer, NPR News. Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Lauren Sommer covers climate change for NPR's Science Desk, from the scientists on the front lines of documenting the warming climate to the way those changes are reshaping communities and ecosystems around the world.