The Current·Q&A

Are sperm whales smarter than we think? Study suggests they learned to evade 19th-century hunters

Sperm whales in the 19th century appear to have learned from each other how to avoid deadly attacks by whalers, according to a new study co-authored by a Halifax marine biologist.

Halifax co-author says he's hopeful whales will also adapt to threats of 21st century

An illustration of a sperm whale being captured. A study published this week in the journal Biology Letters says 19th-century sperm whales learned from each other how to avoid attacks by whalers. ( Hulton Archive/Stringer/Getty Images)

Sperm whales in the 19th century appear to have taught each other how to avoid deadly attacks by whalers, according to a new study co-authored by a Halifax marine biologist. 

The findings were published Wednesday in the peer-reviewed journal Biology Letters.

Researchers came up with the findings by examining logbooks from American whalers working in the North Pacific during the middle of the 19th century, which had been digitized.

Using the number of whale sightings reported, the researchers found that the rate at which whalers succeeded in harpooning the whales they spotted dropped by 58 per cent over the first two years they worked in the region. 

"The whalers themselves wrote of defensive methods that they believed the whales were adopting, including communicating danger within the social group, fleeing — especially upwind — or attacking the whalers," the authors wrote.

And the researchers say the drop in whaler's harpooning success wasn't because vulnerable whales had been picked off — but because the whales lived in "kin-based social units" where they learned defensive behaviour from their fellow creatures.

Marine biologist Hal Whitehead is a professor at Dalhousie University in Halifax and lead author on the study. He spoke with The Current's Matt Galloway about the findings. 

Here is part of their conversation.

Just how smart are sperm whales?

Well, we don't know. But as you said, we're getting more and more suggestions, information that they can behave in pretty smart ways.

In this study, you were looking at whaling data from the 19th century. Why did you go there?

I heard from some historians ...  that the whalers found that the whales very quickly started doing things which made it much harder for the whalers. The whalers were annoyed, and they wrote this down, and the historians reported this. And I thought, "Hmm, interesting." 

So I went to an extraordinary data set which documents the ... whalers of the 19th and 18th century, the digitized logbooks that these guys kept. They sailed all around the world catching sperm whales. And I looked in the North Pacific where we have logbooks from right at the start of the whaling, and I found an extraordinary thing — that in the very first few years, three to five years of that whaling, the success of the whalers ... in catching [sperm whales] went down by about 60 per cent. So I started to think, "Well, what the hell's going on here?" 

We looked at various other options. But the answer seems to be that the whales were learning quickly and learning from each other good methods of avoiding this new and really serious threat that they faced.

You could say that … they learn this over time, this is evolution. I mean, the whales progress and that, but this was happening too fast for evolution, right?

It's happening … much too fast for genetic evolution [which would require generations of selective pressure.]

It's what one might call cultural evolution. You know, the way our culture evolves [is] sometimes really fast, sometimes more slowly. And so this is an example of a non-human culture evolving very fast.

Hal Whitehead, a marine biologist at Dalhousie University in Halifax, co-authored the study on sperm whales. (J. Modigliani)

So if these whales were able to in some ways learn from their mistakes and then pass that along to other whales, what does that tell you?

It reinforces information that we've got from studying living whales, that the information that whales get from each other is vital to them. 

A whale who for some reason was brought up alone, without access to other whales of its species, is probably not going to survive. 

So just as for us, our culture is vital to us. Without our culture, without what we've learned from others, we wouldn't survive. And I suspect the same is true of whales.

An ink and watercolour drawing by whaler Oliver Wilcox in 1837 shows four whaling boats from the ship Canton harpooning six whales in the North Pacific. Researchers used digitized logbooks from 19th century whalers to analyze what might be behind a decrease in harpooning success in the years after whaling began in an area. (New Bedford Whaling Museum via Biology Letters)

What does it tell you about how sperm whales might adapt to threats in this time?

Well, we are threatening them. We're threatening them with things like increasing noise in the ocean, with fishing gear, with plastics, with oceans warming due to climate change. And my hope is that this ability to learn from each other and to adapt quickly may be useful to them as they face these threats. I don't know that, but I hope that. 

But we do know that it actually can get them into trouble. 

They've started stealing fish off fishing lines both in the Pacific and here off the Atlantic. And that's not good for the fishermen. They don't like it, and it's not good for the whales. So it can sometimes lead them down the wrong path.

But as you say, they're in some ways cultural beings like we are.

They are. They are.

I think a lot of people would find that difficult to wrap their heads around. Having studied this for so long, are you surprised by that?

Well, I was. You know, I've gradually become more and more surprised at the depth of this culture. 

I've studied sperm whales for 40 years now, and we started getting hints of it about 20 years ago. And then gradually these hints have grown up. 

I've, you know, found more and more evidence that culture is important to all kinds of bits of their lives, from ... this really important way in which they avoid predators to just how they play.


Written by Kirsten Fenn. Produced by Ashley Fraser. Q&A has been edited for length and clarity.

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