Sperm whales’ communication “alphabet” decoded with AI algorithm - Earth.com

Marina: Welcome to Deep Voices — I'm so glad you're here. I'm Marina, a marine biologist who has spent the better part of my life completely, hopelessly in love with whales and dolphins, and this podcast is where I get to share that love with you. Marina: Before we dive in, a huge thank you to our sponsors who make this show possible. Ada — helping businesses integrate A I into their workflows in smart, practical ways. Ago Consulting — that's "Ahh-Go" — bringing deep expertise in silicon development from A I to SoC. And Zen Semiconductor — an umbrella company with a remarkable portfolio spanning the entire silicon industry. We couldn't do this without them. Marina: Today's episode is one I've been genuinely buzzing about, because the stories we're covering sit right at the intersection of ancient animal intelligence and cutting-edge technology. We're going to talk about how sperm whales may have something like an alphabet — yes, an actual structured communication system — and the A I researchers working day and night to crack it. We're going to explore what it would even mean to truly listen to a whale. And we're going to end with a story about connection — real, documented, heart-stopping connection between humans and the sea. Let's go deep. Marina: VOICES OF THE DEEP Marina: Okay, I want you to picture the ocean at about a thousand meters down. It is ink black. The pressure would crush you. And somewhere in that darkness, a sperm whale clicks. Marina: Not randomly. Not like noise. It clicks with intention — a rapid-fire sequence of sounds called codas, sharp little percussive pulses that travel through the water with extraordinary precision. And now, researchers believe those codas may be organized into something far more sophisticated than anyone previously imagined — something that looks, structurally, a lot like an alphabet. Marina: Sperm whales are remarkable communicators. They're the loudest animals on Earth — their clicks can reach around 230 decibels, which is almost incomprehensible. They use a specialized organ in their heads called the spermaceti organ to produce these sounds, and the clicks bounce around internally before being projected outward. It's one of the most complex sound-production systems in the animal kingdom. Marina: For decades, researchers have known that sperm whales use codas — these patterned click sequences — to communicate with each other, especially within their tight-knit family groups. Different populations, different clans, have different coda repertoires, almost like regional dialects. A clan in the Caribbean sounds different from a clan in the Pacific. That alone is extraordinary. Marina: But recent work has pushed this even further. Researchers analyzing sperm whale codas with A I tools have found evidence of a combinatorial structure — meaning the whales aren't just producing a fixed set of calls. They appear to be combining elements, varying rhythm, tempo, ornamentation, and rubato — that's a musical term, a kind of expressive timing variation — in ways that generate a huge range of distinct signals. Earth.com recently covered a study describing this as the decoding of a sperm whale communication "alphabet," and while scientists are careful about that word, the underlying finding is genuinely stunning. Marina: The idea is that sperm whales may not just have a set of fixed calls like "danger" or "food here." They may be constructing their communication the way we construct words from letters — building complexity from simpler units. That is a hallmark of sophisticated communication systems. It doesn't prove they have language in the way we use that word, but it opens a door that, honestly, I'm not sure we're ready for what's on the other side. Marina: And what strikes me most is this: these whales have been clicking at each other in the deep ocean for millions of years. We are just now, in 2024 and 2025, beginning to have the tools to even ask the right questions about what they might be saying. That humbles me every single time. Marina: CULTURE & DECODING Marina: So who is actually doing this work? How do you even begin to decode the communication of a deep-diving whale that spends most of its life in places humans can barely survive? Marina: That's where Project CETI comes in — and if you haven't heard of this project, let me tell you, it is one of the most ambitious scientific endeavors happening right now, anywhere, in any field. CETI stands for Cetacean Translation Initiative, and their goal — stated plainly — is to use machine learning and A I to decode sperm whale communication. Marina: The project has brought together marine biologists, linguists, cryptographers, computer scientists, and roboticists. It won the TED Audacious Project Prize, which goes to ideas so bold they make you catch your breath. Imperial College London is among the institutions involved, with researchers leading the machine learning side of the work — developing the algorithms that can find patterns in sperm whale codas at a scale no human team could manage alone. Marina: Here's what that looks like in practice. The team deploys underwater listening systems — hydrophones — near sperm whale family groups in the waters around Dominica in the Caribbean. They're also developing underwater drones and wearable tags for the whales that can capture audio close to the source. The goal is to collect thousands of hours of recordings, paired with behavioral data — what is the whale doing when it makes this sound? Who is it with? What happens next? Marina: And then the A I gets to work. The machine learning models analyze the acoustic features of thousands of codas — their timing, their click intervals, their fine structure — looking for patterns, for structure, for the kinds of regularities that suggest meaning. It's similar, conceptually, to how early codebreakers approached encrypted messages. You look for patterns. You look for what varies and what stays the same. You look for context. Marina: Nature magazine has explored this broader question — A I is helping decode animal communication across many species, from bees to elephants to, yes, whales — but they also ask the harder question: even if we find patterns, even if we identify structure, will we ever be able to actually communicate back? Will it be a two-way conversation? Marina: And honestly, scientists are divided on this. Some are cautious — finding structure in a signal is very different from understanding meaning, and meaning is deeply tied to context, to lived experience, to a world we don't inhabit. A sperm whale's life — the darkness, the family bonds forged over decades, the collaborative hunts, the grief — is so different from ours that even if we cracked every acoustic pattern, translation might remain elusive. Marina: But others point out that we've surprised ourselves before. Dolphin research has shown that bottlenose dolphins use signature whistles — unique, individual calls that function almost like names. They address each other by name. They remember the signature whistles of individuals they haven't seen in decades. That was considered extraordinary when it was first documented, and now it's established science. Marina: The Earth Island Institute asks a question I find deeply moving: if whales speak, what would it mean to truly listen? Not just to record and analyze — but to genuinely listen, with all the ethical weight that carries. Because if these animals are communicating with something like language, that changes everything — how we think about them, how we treat them, what we owe them. Project CETI isn't just a science project. It's a moral reckoning dressed up in hydrophones and algorithms. Marina: What I love about this moment in history is that for the first time, we have tools — A I, machine learning, vast computational power — that can process the scale of data these questions require. And the scientists using them are, by and large, doing so with a kind of reverence. They're not trying to make whales perform tricks. They're trying to understand beings that have been living rich, complex, communicative lives in the ocean for far longer than our species has existed. Marina: A CETACEAN-AND-PEOPLE STORY Marina: I want to close today with a story that has nothing to do with algorithms or data, and everything to do with what happens when two very different kinds of minds actually meet. Marina: In 2011, a humpback whale off the coast of San Francisco became entangled in crab trap lines — hundreds of pounds of rope wrapped around her body, her flippers, even her mouth. She was in serious distress, barely able to stay at the surface. A group of divers was called in to attempt a rescue. Marina: Now, I want you to understand what this looks like from the divers' perspective. A humpback whale is about 45 feet long and weighs around 40 tons. In the water, she is not a creature you approach lightly. A single sweep of her tail — even unintentional — could be fatal. The divers went in anyway. Marina: They worked for over an hour, cutting rope with curved knives, carefully, methodically freeing her from the lines that had wrapped around her. It was painstaking, dangerous work in open ocean water, the whale mostly still, as if she understood what was happening. And when they finally cut the last line free, something happened that none of those divers has ever forgotten. Marina: The whale didn't just swim away. She circled. She swam to each diver, one by one, and nudged them gently — the kind of contact that, in a whale of that size, is unmistakably deliberate. One of the divers, James Moskito, described being pushed gently through the water by her. He said later that he could see her eye — this enormous, ancient eye — looking directly at him. He said he felt, in that moment, that she was saying thank you. Marina: Now, I'm a scientist. I'm careful with words like "thank you" when we're talking about animal cognition. But here's what I can say: humpback whales are highly intelligent, socially complex animals. They have spindle neurons — a type of brain cell associated in humans with social awareness and emotional response — in their brains. They form long-term bonds. They communicate over vast distances with songs of extraordinary complexity. The idea that this whale was engaging in something intentional, something responsive, something that functioned like gratitude — it is not scientifically outrageous. It is, in fact, consistent with what we know about them. Marina: And what strikes me about this story is what it suggests about the nature of encounter. These divers went into the water out of compassion — no cameras, no audience, just the work. And the whale responded to that. Whatever was happening in her mind, she chose to stay. She chose to make contact. She chose, in some sense, to acknowledge them. Marina: These moments of cross-species recognition — and there are many documented ones, from dolphins guiding lost swimmers to shore, to whales approaching boats seemingly to show off their calves — these moments feel important to me not just as data points but as something more. They remind us that the ocean is not empty of minds. It is full of them, ancient and complex and alive, doing things we are only beginning to understand. Marina: If we can learn to listen — really listen, with the patience and the technology and the humility this requires — I believe the ocean is going to tell us things that change us fundamentally. And I can't wait. Marina: That's our episode for today, and honestly, I could talk about this for hours — the alphabet of the sperm whales, the audacious dream of Project CETI, a whale who swam back to say goodbye to the people who saved her. These stories remind me why I fell in love with the sea in the first place, and why I believe its voices deserve to be heard. Marina: Deep Voices is brought to you by Ada, Ago Consulting, and Zen Semiconductor — three companies that understand the power of technology to help us ask bigger questions and reach further into the unknown. I'm grateful for them, and I'm grateful for you. Marina: If today's stories moved you — and I hope they did — please subscribe wherever you get your podcasts, leave a review if you can, and share the show with someone you think needs a little ocean in their life. All the sources and links for today's stories are in the show notes, so please go check them out — the researchers doing this work deserve your attention. Marina: I'm Marina. Keep listening for the deep voices. I'll see you next time.