JOHN DANKOSKY: This is Science Friday. I’m John Dankosky, in for Ira. If you’ve ever watched a nature show, you’re probably familiar with what a whale call sounds like. Those deep, echoing sounds and high-pitched chirps are the song of the humpback whale.

But there’s another whale with a more complicated repertoire. My next guest calls them the jazz singers of the ocean, the bowhead whale. Her team put a hydrophone down and recorded the songbook of these deep sea singers for three years. And they heard quite the concert down there. Their findings were published this week in the journal Biology Letters.

Kate Stafford is an author on that study. She’s also principal oceanographer at the Applied Physics Lab at the University of Washington. Kate, welcome to Science Friday.

KATE STAFFORD: Thanks so much, John. I’m very glad to be here.

JOHN DANKOSKY: And we’re glad to have you here. So tell us about the bowhead whale, first of all. It’s not a species that many of us have heard about.

KATE STAFFORD: No, it’s not. And I would have to say that the bowhead whale, at least in my opinion– and I confess to being biased– is a superlative whale in many ways. It’s the only large whale that lives year-round in the Arctic. Bowhead whales can live 200 years long, which is really remarkable.

JOHN DANKOSKY: Wow.

KATE STAFFORD: They can break through a foot and a half of ice. And they’ve got both the thickest blubber and the longest baleen of any whale.

JOHN DANKOSKY: So they do sound superlative. Well, before we talk much more about the whale, let’s hear one of the recordings that you captured. I really want to hear this. Let’s hear what these whales sound like.

[WHALE SONG]

So Kate, what are we hearing there?

KATE STAFFORD: So what you’re hearing is 1 of 184 different songs that my colleagues at the Norwegian Polar Institute and I recorded on a hydrophone, which is an underwater microphone that we put out in Fram Strait for 3 years.

JOHN DANKOSKY: And the song that we’re hearing there is quite a big different from what we are used to hearing from humpback whales. Tell us a little bit more about that. It seems as though these songs change quite a bit over time.

KATE STAFFORD: They do. So, John, as you said earlier, we really know quite a bit about humpback whales. Of all the large whales, only the bowhead and the humpback whales sing really elaborate, complex songs. Whales like blue whales and fin whales also sing, but their songs are much simpler.

And humpback whales, all the males in a single population will sing the same song within a breeding season. And that song might change through the season, but everybody seems to adopt those changes. And then in the following year, they’ll sing something different, but they will often incorporate phrases or notes that they used the year before.

With bowhead whales, not only are they singing many, many different songs within a year, all the data that we’ve looked at and listened to, we have never heard the same song or the same phrase between years.

JOHN DANKOSKY: That’s so interesting. So you would think if you listened to birdsong, for instance, that you would have a song that would allow other birds to know that you’re around or identify yourself as a certain species. And you say that other whales sing about the same song. Why do you think it is the bowheads are so, I don’t know, improvisational?

KATE STAFFORD: Boy, that is a really good question, John. And it’s something that actually does keep me up at night. So my co-authors and I have some theories.

But what I’ve been thinking about a lot lately is I think the environment is what has driven why bowhead whales are so variable. So this is an animal that sings in the middle of winter under the polar night, so 24-hour darkness, and 95% to 100% sea ice concentration. So it’s cold, it’s dark, and it’s ice-covered. And maybe in that environment, singing and producing variable songs is the best way to get your message across. Bowhead whales don’t have to identify themselves as a bowhead whale in the Arctic, because they’re the only large whale there.

JOHN DANKOSKY: That environment, perhaps with thick ice cover overhead, allows the song, I assume, to sound pretty good. I don’t know. Maybe it’s like me when I go into the stairway and all of a sudden I sound like Frank Sinatra. Is it something like that?

KATE STAFFORD: Well, that’s one theory. But of course, it depends upon the quality of the ice overhead. But we do think that having that nice ice might make for a beautiful, almost concert effect.

JOHN DANKOSKY: Are baleen whales the only types of whales that sing?

KATE STAFFORD: As far as we know, yes. They’re not the only types of whales that make sound. All marine mammals, and all whales of course, make sound, because for them, sound is actually the most important sense. Sound travels much further under water than light does. They use sound to navigate, to find food, to find mates, and to communicate. So for all whales, sound is really important. And for some baleen whales, singing appears to be a really important reproductive display.

JOHN DANKOSKY: And can you explain briefly how exactly they make these beautiful sounds? I mean, what are they singing out of?

KATE STAFFORD: That is another really good question. We don’t think they’re singing out of their mouths. For the baleen whales, at least, we believe that they are cycling air between their lungs and this organ called a laryngeal sac that hangs off their trachea. And maybe very similar to the way in which a bagpiper might expel air from the bag through the chanters, we think that whales are recycling air between their lungs and this laryngeal sac. But we don’t know.

JOHN DANKOSKY: Wow. Circular breathing, just like a jazz saxophonist. So you say this–

KATE STAFFORD: Exactly.

JOHN DANKOSKY: This keeps you up at night, so what more do you want to know about the bowhead whale and its beautiful songs? What haven’t you learned yet that you’re looking for in your work?

KATE STAFFORD: Well, the research that we’ve been doing, as so much scientific research does, has led to a lot more questions than answers. So because they’re doing this behavior in the middle of winter, in the ice, in the dark, we don’t know whether individual animals have their own song, or whether groups of animals have their own song, or whether individuals change their songs within and between years.

And although we have good evidence from humpback whales and blue whales and fin whales and other mammals and birds and frogs that it’s males that produce this song, we don’t know for certain that bowhead males sing. I suspect they do, but we don’t know.

JOHN DANKOSKY: We’ve run out of time. But I thank you for bringing us these beautiful songs. We’ll listen to more and think more about them. Kate Stafford is a professor of oceanography at the University of Washington in Seattle. Kate, thanks so much.

KATE STAFFORD: Thank you, John. And enjoy the songs.

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