New Footage Shows How Narwhals Use Tusks To Hunt And Play

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman. Later in the hour, a new study shows a rapid decline across butterfly species in the US. What’s driving it, and is there anything to do? Plus, a private company has sent a lander to the moon. We’ll talk about it.

But first, as a reward for getting through the week, we are taking a polar plunge into the science of sea unicorns. I am talking, of course, about narwhals. These are the mysterious Arctic whales with those long, twirly tusks protruding from their foreheads. They look like a creature out of a fairy tale, and it turns out we don’t know too much about them. They’re hard to study, partly because they live so far north in the remote Arctic.

So an international team of researchers had this idea. They turned to drones to observe them and learned all these new things about this storied creature. On the horn to tell us more is Dr. Greg O’Corry Crowe, a research professor at Florida Atlantic University based in Boca Raton, Florida. Greg, welcome to Science Friday.

GREG O’CORRY CROWE: Thank you for having me.

FLORA LICHTMAN: OK, are narwhals mysterious?

GREG O’CORRY CROWE: Yes, I think so. I think they fire the human imagination, as you say, with their incredible tusks that are truly amazing natural features. And as you mentioned earlier, they live in quite remote, challenging locations and are known to few. But, fortunately for us, we’ve partnered with Indigenous communities in the far north to set out and learn more about this incredible animal.

FLORA LICHTMAN: Well, what did you learn about them?

GREG O’CORRY CROWE: So a big challenge up to now has been actually just getting to observe them in the wild. We’ve been fortunate to work from boats sometimes and from the sea ice, but with the advent of drones, we’ve been able to sort of get this bird’s eye view and this unique insight. And we’re learning that they have very complex, sophisticated societies, and there’s a lot of interesting interactions between individual animals and other species. And the hits just keep coming. Every day we fly, we see something completely new and amazing.

FLORA LICHTMAN: Well, let’s dive into some of those interactions. What are they doing?

GREG O’CORRY CROWE: So in the summer, the general understanding is they’ve spent a long time in the winter feeding, and they’ve spent a lot of the spring migrating north as the ice retreats. And so in the summer when they come, in some locations, close to shore, it really wasn’t very clear what they were doing. And what we’re starting to realize is they spend a lot of time socializing, probably resting after a long journey.

And when animals have time on their hands, they get up to some pretty interesting behaviors. And one of them we got to see was how they actually used their tusks in a way we never really knew about.

FLORA LICHTMAN: What are they doing with those tusks? Tell us.

GREG O’CORRY CROWE: So, basically, the general understanding is that these tusks have evolved as what we call secondary sexual characteristics. They’re involved in mating behavior. Only males or predominantly males have them. But they’re using their tusks sometimes to track down, manipulate, stun, and sometimes kill fish. So they actually use their tusks as not just a display or a weapon. They use it as a kind of surgical instrument to catch prey.

FLORA LICHTMAN: To spear them, or what are they doing with them?

GREG O’CORRY CROWE: So that’s a very good question. They usually seem to focus on a particular fish– in this case, the Arctic char– track it, and then they whack it, basically, and slow it down, maybe stun it, and then consume it.

We started to pick up on other things, and in one amazing encounter, we realized that they actually weren’t trying to really even injure, let alone kill and consume the fish. It appeared that what they were actually doing was just playing and exploring.

FLORA LICHTMAN: Like a cat toying with a mouse?

GREG O’CORRY CROWE: Yes, it was like play with your food, you know? And so this is the first sort of documented example of narwhals playing.

The other thing that was so striking was the tusk looks like a giant broadsword that you might wield to inflict some injury, and yet they were using it like a surgical instrument in very precisely interrogating, messing with basically this fish. Several times the fish would stop as if to say, what are you guys doing?

FLORA LICHTMAN: I’ve had enough.

GREG O’CORRY CROWE: I’ve had enough of this. And in the process of actually observing this, we noticed a lot of interesting interactions between the narwhals themselves, and some of it looks like it’s social learning and possibly even social instruction from one whale to another, which is pretty remarkable.

FLORA LICHTMAN: Like one narwhal is doing something with their tusk, and then the other one copies it?

GREG O’CORRY CROWE: Yeah, I think, and that’s something we are particularly focused on. We’re doing a lot of research on beluga whales, as well as narwhals, and trying to understand how that kind of social learning short circuits ways to innovate and start sort of new behaviors in the changing Arctic. So rather than everybody having to figure it out for themselves, somebody has a bright idea, and everybody copies it, and things kind of go viral.

FLORA LICHTMAN: I mean, isn’t this the basis of culture, passing down ideas?

GREG O’CORRY CROWE: Ah, you’ve asked a wonderful question. So I agree. I think we’re starting to see other animals that have culture as well as humans and other primates, including beluga whales, and the crux of that is passing down traditional behaviors and activities through social learning.

But one of the concerns I have is sometimes cultures and traditions, as we know, can become hidebound by tradition. And if something changes, are you going to be actually able to respond? And so in the Arctic, are animals, like narwhals and belugas, going to be stuck in a kind of rut as to, well, we’ve always done it this way versus, on the other side, the innovators saying, well let’s try something new? And social learning is key to both of those things, and that’s really what we’re up there trying to understand.

FLORA LICHTMAN: How are narwhals adapting to climate-driven changes in the Arctic? Are they threatened? Is it harming them?

GREG O’CORRY CROWE: Well, it’s quite challenging, and they’re probably one of the most challenging species to study. And fortunately, we have our Indigenous partners in Nunavut and other places who are the real experts on narwhal, and their concern is that it’s not just the loss of sea ice and maybe shifting prey bases but the increase in human activities and especially increases in ocean noise from shipping and oil and gas exploration. So our team, which includes a lot of Canadian scientists from the Department of Fisheries and Oceans and some of the subsistence hunters from villages in Nunavut, are trying to actually ask that particular question. How are they dealing with this major shift?

FLORA LICHTMAN: A big aha for our team– because we all watched the videos associated with this paper. And, listeners, you can watch them too at our website at sciencefriday.com/tusk. Highly recommend. A big aha for us was how long these tusks are.

GREG O’CORRY CROWE: Oh yeah. No, it’s incredible. I mean, they can grow to 10 feet in length, and they really are a remarkable structure. And when you’re sort of standing in the water right beside the narwhal, you’re just mesmerized by the beauty of it as well because it has this beautiful scrolled pattern. It almost looks like it has been carved. And when seafarers brought these back to Europe and to Asia, you can imagine how the myth of the unicorn became real to a lot of people. They’re just magnificent structures.

FLORA LICHTMAN: What are they made of?

GREG O’CORRY CROWE: They are a tooth. So, basically, they’re a very specialized tooth that comes out through the front of the head, as I said, predominantly in males. They are, interestingly, quite sensitive to the environment in terms of they have the ability to sort of respond to changes in salinity and temperature. And so one other potential use is that the narwhal tusk is kind of an environmental probe.

FLORA LICHTMAN: Really, like an antenna or something?

GREG O’CORRY CROWE: Well, it’s like a Swiss Army knife. It has multiple applications. So I think there’s just so much more to learn.

The other thing I thought was fascinating was– and you’ll see it from the videos– how subtle their movements are, how precise and careful their behavior is with the fish, and that ability to move it with such precision and manipulate a small object was really incredible.

FLORA LICHTMAN: Yeah, especially when it’s 10 feet long.

GREG O’CORRY CROWE: Exactly.

FLORA LICHTMAN: Like, I can barely hold a fork. You know what I mean?

GREG O’CORRY CROWE: True. Yeah, I mean, and it’s a heavy object as well. So we want to continue this research. We want to go back and learn more. But every day, as I said in camp, we would just review what we just saw and look at each other and go, did we really just see that?

FLORA LICHTMAN: Wow. As someone who has experienced a drone buzzing over my head, they can be annoying. Did you have to worry about disturbing the narwhals?

GREG O’CORRY CROWE: Well, a very good point. And I think a lot of the impetus behind this work was, could we use methods that minimize disturbance? And so could we fly drones that are quiet and fly them at an altitude so we are not disturbing the animals? We deployed hydrophones in the water to listen to them.

And so the whole concept was rather than maybe the traditional methods of trying to get close in boats and get hands on animals, could we take a step back? And that has been the really exciting part. Yes, we have this new technology, but it’s old-school science. It’s about stepping back and just observing nature and letting it unfold in front of you. And we were able to, without disturbing these animals, just sort of become kind of part of their environment. And all these things started to happen around us, and it was like an eye opener for a lot of us that we need to go back to this what I call notebook and pencil kind of natural history.

FLORA LICHTMAN: That’s fascinating that this very new technology actually allows us to go back to tried-and-true methods of observational science.

GREG O’CORRY CROWE: Yes, and I think technology over the last 30, 40 years has been a revelation and a revolution in a lot of what we do with remote cetacean species, whether it’s satellite tagging or genetics or aerial surveys, and they will continue to provide new insights.

FLORA LICHTMAN: I think a lot of people at one time in their life, myself included, have dreamed of being a marine biologist. Is studying narwhals like unlocking expert level for marine biology?

GREG O’CORRY CROWE: I mean, to me, I’ve had a passion for the high north and for looking at social species. And so in many ways, beluga whales and narwhals are the holy grail for what I want to study.

And what is very important is there’s also been this kind of dawning among scientists that stakeholders, particularly Indigenous people and their knowledge, is just as valuable and, in some cases, more so. And so these kind of team approaches– as you say, this international team– is the only way we can unlock these kind of secrets. But at the end of the day, it’s about just spending time in the wilderness with animals, and then they will reveal their secrets.

FLORA LICHTMAN: Thank you for taking us into the wilderness today. It’s very refreshing.

GREG O’CORRY CROWE: Thank you. Thank you very much. And we hope to be able to continue this work and maybe give you some more exciting news in the future.

FLORA LICHTMAN: Any time. Please, any time. Dr. Greg O’Corry Crowe is a research professor at Florida Atlantic University based in Boca Raton, Florida.

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