Why Are Whales So Big? with Nick Pyenson! - podcast episode cover

Why Are Whales So Big? with Nick Pyenson!

Apr 07, 202627 min
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Episode description

How long do whales live, and how do scientists figure out their age? What does it take to sustain a whale's enormous size? And why do whales have mustaches and belly buttons? Featuring Nick Pyenson, author of Spying on Whales and curator of marine mammal fossils for the Smithsonian.

This episode originally aired on September 12, 2018.

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Transcript

Speaker 1

Guess what will? What's that mango?

Speaker 2

So you know those Golden records that traveled on the Voyager spacecraft.

Speaker 3

Yeah, they were loaded up with greetings in different languages and these concertos. Wasn't actually Johnny be Good on there too?

Speaker 2

Yeah, that's right, there's some Chuck Berry on the record. But I was reading this new book by Nick Pinson. It's called Spying on Whales, and one of the things he says is that there are actually whale songs on that record as well. So in the nineteen seventies, scientists had just discovered that whales have these complex songs that they repeat in loops, and each whale improvises on that loop.

It's really remarkable. But Pines's point is that in the nearly fifty years since, we still don't really understand these songs. But even then we find them so intriguing and so beautiful that we're happy to throw them on a record in case aliens might find them interesting too.

Speaker 1

But reading this book.

Speaker 2

Made me think we should really dig into whales, like why are they so large? How do they sustain these massive bodies? I mean, these creatures are bigger than any dinosaurs that have ever lived, and also, why do they have belly buttons?

Speaker 1

Let's dive in.

Speaker 3

Hey their podcast listeners, Welcome to Part Time Genius. I'm Will Pearson and as always I'm joined by my good friend Mangesh hot Ticket and the man on the other side of the soundproof glass not fully prepared today, Mango. I do see. He's got eBay up on his computer and he's looking up all of these Shamoo T shirts Shamoo coffee mugs, so he's probably gonna order some of those. I don't know when he's gonna wear them. I'm a little bit disappointed, but I'm sure he'll get something. But

that's our good friend and producer Tristan McNeil. Now today on the program, we're chatting with Nick Pynson. He's the curator of Fossil Marine Man at the Smithsonian Institute's National Museum of Natural History, which is of course in Washington, DC, and he's the author of this wonderful new book called Spying on Whales, The Past, Present, and Future of Earth's most awesome creatures. Nick Pyenson, Welcome to Part Time Genius.

Speaker 4

Happy to be here.

Speaker 3

So going way back, one of the first things I stumbled into when reading your book. Here was that the first whales were land dwelling creatures the size of a German shepherd, that they walked on four legs and even had the snout instead of a blowhole. And I have to admit, Nick, when I first saw this fact, I thought, uh, oh, this guy might not know what a whale is like. That is not describing a whale. So can you explain them?

I mean, that is so bizarre to both know that that connection is there and then to know how that connection is there. So can you talk us through this a little bit.

Speaker 4

Let's go back to have a whale in your head, and you're probably imagining a humpback whale or a killer whale and just looking at the basics of its DNA to know genealogical relationships. That whale in your head is most closely related to mammals that have fore legs and live on land for the most part, so that those are deer, pigs, cattle, sheep, hippos, which are semi aquatic. They swim in the water pretty well. But you have four weight bearing limbs and whales really don't look like

that at all. So the earlased whales had for weight bearing limbs. It makes them look a lot like their near relatives today. But in the process of about ten million years, we have this great fossil record of how they've transformed, the loss of hind limbs, the transformation of fore limbs into paddles, and then all the changes that

happen to their skulls. Because when they undergo these transitions, especially like this one from land to sea, well your you know, vision has to change, how you smell changes, how you hear changes. We have that documented in the fossil record.

Speaker 2

What sort of timeline are we looking at here, like, when does this dog sort of appear on Earth?

Speaker 4

You should be really careful and say dog like. Dog like dogs are a completely different group of mammoed. So this happens in about the space of a ten million years, from fifty to about forty million years ago. And this time period is interesting because it's during a period that was the last greenhouse Earth, and that's the last time in Earth history that we had global carbon dioxide concentrations that are closest to the ones that we may head

to in the coming century or two. Whales evolved in an island archipelago that bordered the equator, so territory that is now India, Pakistan, Afghanistan, the entire Middle East that used to be a giant equatorial seaway. Today that's now been reduced to the metatre Tranian, but fifty plus million years ago that was open waters, and there happened to be this giant archipelago of land. And you know, if you read anything about evolution on island, you know, crazy

stuff happens. So I'm not so surprised that the earliest whales happened in this setting.

Speaker 3

You know, Nick, there's some great illustrations in the book, and one is if this basilosaurus and I guess this was one of the first fully aquatic whales. And supposedly this whale had one of the strongest bites of any mammal ever, or at least as you've said here. So how do we know this?

Speaker 4

That's a great question. So one of the ways that we can figure out how strong an extinct organism might bite is by modeling it. So you can create a computer model based on the digital data the geometry of that animal's teeth or its skull I'd say especially teeth plus skull, because you want to know the bone that's

holding the business end of whatever's chomping down. And when people have done those computational analyzes, and they do it with Basilsaurus, which again had a three foot long skull, So one, they're not that many mammals with teeth that have three foot long skulls. A polar bearer may have a skull that's forty centimeters long, that's barely that's not even a foot and a half. But Basilsaurus had a three foot long skull with these giant teeth that are

the size of your palm. So the numbers that you get are that it has a byte force unrivaled by any other mammal.

Speaker 2

So Nick, well, one thing I still don't understand is how did wales get so big and why did they stop growing? Like why does a one hundred and ten foot body work for them? But maybe not a two hunderd foot body.

Speaker 4

So that's that's a question I tried to explore in the book, which and emphasize that getting big over evolutionary time is really a set of trade offs. There's a lot of reasons that it might be advantageous to get really big, then there are a lot of reasons why it may not be. It seems like for filter feeding whales they only get big in the last few million years.

And what's interesting about that time frame is, in contrast to greenhouse Earth, during the first few million years of whale evolution, the last few million years have been happening under ice age ears, a time when we have ice caps both south and north global oceans became patchier in space and time in terms of their resources with the

onset of the ice ages. So these kind of these natural history films where you see giant schools of fish and bait balls and krill aggregations that happen off the coast of South Africa or off of Chile or off of California, those are very recent geologic phenomena which haven't really been around that long.

Speaker 1

And we think this is.

Speaker 4

Deeply tied to the selective forces that allowed whales to become big, so migrating the long distances to arrive at those places where food is very dense in space and time. Being big helps, But on the cost side, if you're a lunch feeding whale, you really can't be much bigger than about one hundred and ten feet otherwise you can't close your mouth fast enough. So's those are the trade offs with getting big. Now, could a different kind of

whale get much bigger? Maybe, but that hasn't yet evolved in as far as we know.

Speaker 3

So, Nick, you talk about the whales traveling, I'm curious. I know different types of whales travel different distances, but how long are we talking for some whales?

Speaker 4

So some whales don't range that far, but others do in these filter feeding whales, So ones that are like humpbacks or blue whales or minky whales, they can range over tens of thousands of miles. Gray whales, for example, have no problem, it seems, migrating twenty thousand miles. Humpacks will migrate from Maui in Hawaii to the Panhandle of

Alaska every year. That's a scale that I really tried to convey in the book, is that whales range over entire ocean basins in many cases, so they're living at these big scales. That's a way that whales are teaching us about these bigger ideas about how oceans work. That I think is really important.

Speaker 1

Nick.

Speaker 2

We've got so many more questions, but we've got to take a little break first. Welcome back to part time genius. We're here with Nick Pines, and you know, when you were discussing the size of a whale and how they can only get so large because they need their jaws

to climb fast enough to get the food. I was fascinated by some of the different strategies that whales used to hunt that you've described, and I was curious if you could sort of go through some of those, because like the way they can hold their breath and die deep, or almost turn their jaws into parachutes, or how some pirouette when they lunch.

Speaker 1

It was just really.

Speaker 2

Beautiful and I'd love for the listeners to be able to hear some of that stuff.

Speaker 4

Sure, I mean, I think it goes back to this idealized whale that you have in your head. It oversimplifies the incredible diversity of living whales, to say nothing about all the crazy extinct ones that we know of. But among the living whales, you'll see some have a mustachioed fringe hanging from the top of their mouth. That's baileing. And so those are the filter feeding whales. That's one group. The other one are toothed whales. Now, some of the

toothed whales have teeth. Others don't, but they all echo locate. They use a form of biological sonar to navigate to hunt. The filter feeding ones will use their mustachioed fringe of baileen to capture aggregates of prey in bulk, so you're making the highest return on the investment of feeding style. And some of these filter feeders will lunge the way a blue whale will or a humpback. Others do a

style of filter feeding called skim feeding. So these are like bowheads and right whales where they'll hover around the surface and they're not teen gulps, they're just kind of passing through a giant super organism of prey. For the other group of whales, the toothed whales, they use echolocation. And in some cases these are the deep diving ones that will dive thousands of feet deep in search of prey,

sperm whales, beaked whales, even many oceanic dolphins. A bottomnosed dolphin will dive very very deep beyond the reach of light for their prey. And the way how you can do that is if you have a way of navigating an underwater world without light, and that's using sound. This is an outstanding question, is why haven't whale prey toothed whale prey of all defenses against echolocation, because it seems like a supremely advantageous tool and to hunt. And that's

still not entirely well known. And that's important because we don't actually see whales feeding at depth. I mean, this whole story of the squid and the whale, sperm whales feeding on giant squid, nobody's ever seen that. We see the effects of that, and we would all love to see it. I mean, that's just one of these amazing you know, if you could ever get a BBC film

crew to film it, that would be awesome. We've never seen it, so we have to infer it either from gut contents or the scars or chunks of giant squid tentacles that float around sperm whales after they come to the surface. It's just there's a lot about whale science that we don't see directly, so we have to be clever about how we study it.

Speaker 3

Well. It seems for you know, not for lack of trying, though, because you talk about that echolocation and how it's so sophisticated in some whales that you know, even our military has invested, especially in the sixties, so much in studying that ability to echo locate. Why is it so much more sophisticated than what we're able to create with you know, computers and all the technology that we have.

Speaker 4

Well, I mean, whales have the advantage of evolution, the advance of tens of millions of years of evolution for that right, evolution in an environment that's actually really complex and has properties that are very different from the one that we operate in daily. I mean, water is a different medium, has different properties for the physics of signals moving through it, whether it's sound or light. Whales have had tens of millions of years to evolve solutions to that.

Speaker 2

So one thing I didn't realize before this was how long a whale could live. And in your chapter on Arctic time machines, you talk about bowhead whales and how finding harpoons actually helped us determine their life spans.

Speaker 1

Can you talk a little bit about that.

Speaker 4

Absolutely. I mean, it's I think surprising people to realize that Americans whale today. It just doesn't happen typically in the lower forty eight States, but many indigenous cultures in the Arctic require marine mammal meat as sustenance. That's food for how people live, and this is ongoing in the North Slope of Alaska. And by recovering some of these bowhead whale carcasses, what scientists have found is tools embedded in these in the bodies of these bowhead whales that

clearly came from a different era of hunting. These harpoon heads are almost like iPhones or smartphones in some ways, and that you can tell when they must have been embedded in the body based on their technology generation, So you know exactly so there was a changeover from stone harpoons to metal harpoons in the nineteenth century. And you know that the whale that was an unsuccessful strike must have been an adult when it was hit, because a

juvenile would not have survived. So that whale that was collected in the late twentieth century in this case must have been well over one hundred years old, and the best guess was about one hundred and thirty. And that exactly parallels the kind of data you can get from biological tissues from their ovaries. So different lines of evidence.

You're telling us that bowhead whales are able to live much more than a century, and some of the immunoacidy it was coming back with data of two hundred years, and so that's I mean, it seems unbelievable. But I think the implication of that is that there are whales that have lived through the entire rise and fall of major historical events in human history, like industrial whaling, or the rise of atomic weapons testing, or you name it.

In terms of our technological innovation or the things we put out in the environment, whales, individual whales have persisted through that. So by if we were able to study these whales in whatever form, they probably could tell us a lot about what has happened to the environment. Fortunately, in places like the Smithsonian we have bowhead bailein that goes back well well over one hundred and fifty years.

If bilein is able to tell us about isotopic history, so the chemical history of the environment, then these pieces of bowhead baileen from the nineteenth century before fossil fuels were burned could tell us a lot about how the world's changed.

Speaker 1

That's really interesting.

Speaker 2

So you know, one thing you mentioned there was whaling, and I was fascinated that you actually worked or observed at a whaling station in Iceland, and I kind of wouldn't have expected that commercial whaling and this pure scientific study would have intersected like that. Can you talk a little bit about like why you chose to work there and how it benefited your understanding of wales.

Speaker 4

Whaling is something that's happened for thousands of years in human history and it still goes on today. Many people have emotional reactions to it, for sure, and it's hunting like any other mammal hunting, so it goes all the issues that you may have with big game hunting are

certainly applied to whaling. And there's two main forms today that it happens in commercial whaling, which is undertaken by Iceland and Norway, so they see whaling as no different from a fishery and they sell the meat that's collected that's from a killed whale. And then the other form of whaling is so called scientific whaling that happens in Japan,

you know. And for the latter, I would say that that's agenda driven science, and we should always be skeptical of agenda driven science because that's saying that you kind of know the answer before you go out and look for it, and you know, whaling happens in a social context. And it's clear that scientific whaling in Japan is not really about the science, because we can answer those questions that they have using non lethal ways. That is certainly true.

So scientific whaling really doesn't have that much of a reason for existing. Whaling well, that's within the sovereignty of those nations, and from my standpoint as a scientist, having a relationship with those industrial operations, especially in Iceland, has been a boon to understanding some key parts of the anatomy of these lunch feeding whales, and it's providing information that we wouldn't otherwise have, and that has to do

with the logistics of working with very large carcasses. So a seventy foot fin whale carcass that's freshly killed gives you information that you really couldn't otherwise get, certainly from a stranded whale. When whales strand one, you don't have the equipment at your disposal, usually don't have twenty men with giant knives and steam driven winches to manipulate and rotate the carcass and pull different parts of the anatomy

into some way. That you can actually study it, and certainly the tissue is not as fresh, and when tissue decays, it's far less useful for some kinds of questions, especially if you're looking at nervous tissue or muscle tissue. So the kind of opportunity you have at a commercial whaling station is really different from any other opportunity. That situation is the same that's applied to indigenous hunting. I've colleagues who work in Alaska and opportunistically sample from bowhead mounts.

It's the same kinds of anatomical questions that you can't answer from a stranded whale. So that was what those are kind of the circumstances that allowed us to work in Iceland and yielded all the insights that I talk about in the book.

Speaker 3

Well, what is the population of you know, many of the better known species of whale these days, and how does that compare to where it was, you know, a couple hundred years ago or one thousand years ago. How are whales doing in general? I guess that's the question.

Speaker 4

Many of the whales that were hunted during industrial whaling, and especially in the twentieth century, when many of the populations for many species were brought down ninety plus percent from their baselines. Blue whales now the global population of blue whales is probably around one to five percent of its starting point in the twentieth century, and some two hundred three hundred several hundred thousand blue whales were killed

in the process of the twentieth century alone. That's certainly lowered genetic diversity, that's lowered the individual number of the population. It's changed where those whales are in the world, and maybe even where they migrate, and maybe by extension, the structure and function of ocean food webs by removing that scale biomass. And it's not just blue whales, of course, humpbacks,

minky whales, say whales. So the legacy of whaling on world's whales is vast, and we don't in many cases have that pre whaling baseline, so it's left whale scientists

to infer that. And the two main ways to infer it are either from calculations using current genetic diverse to estimate what the population size was in the past using DNA, and the other approaches look at whaling records and look at catch records and try to infer and we get different magnitudes when we look at those two lines of evidence, but in both cases they tell us there were many, many more whales before whaling. Now, whaling today doesn't really

happen at that scale. A fewer than a thousand whales are killed every year by whaling total globally. Whaling has some serious ethics and geopolitics with it. It doesn't seem like it's going away, and it doesn't seem like as big of a problem to me as global fisheries. In our appetite for seafood, that's really what's causing a lot of the major harm towards whales. You know, I think a whale killed by a harpoon probably dies in a more humane fashion than whales that are entangled in nets.

What's ethical and what's humane about whales is not just a question for scientists. But when we come to the facts of just how many more there are per year, you know, that's I think where we should listen to scientists, and science shouldn't form policies much better.

Speaker 3

Okay, well, we have several more questions for you, Nick, but before we get to those, let's take a quick break. Welcome back to part time Genius we're here with the author of a wonderful new book called Spying on Whales, the past, present, and future of Earth's most awesome creatures. You know, I think when people imagine whales other than size, one of the things they think about at first are

the whale sounds, the whale noises and communication. Over the past few decades, are we getting a better sense of what exactly these whales are trying to communicate with one another or is it still this great mystery?

Speaker 4

Oh, I'd say it's still a great mystery. I mean, it's clear that whales communicate to each other with information rich ways. That content of the signal that they're using to communicate with each other acoustically is saying a lot. Now what it means we don't really know. We don't have a context for that meaning. So we don't know if they're saying, like, hey, lunch is over there, or the answer to the universe is blank, you know. I mean,

it's just it's fundamentally inscrutable. We really haven't hacked that. And I think that has a lot to do with the complexity of whales on the one hand, and the environment they live in on the other, and our best way is to investigate that are whales in captivity which may be doing something very different from what whales in the wild are doing. And again, that's logistically really challenging

to do. And mysteries aren't bad things in science. Mysteries, I think are great things and a source of inspiration and creativity. So I'm actually, you know, as I say in the book, I think this is the golden age for whale science. We're learning more about whales in more ways than we ever have before, so I'm really hopeful and enthusiastic to see what future scientists do.

Speaker 2

You know, Nick, I loved reading about all the adventures you go on in this book, but I also really loved just the little details I hadn't thought about whales, like that they have belly buttons, or that they can be right or left handed, or that they come up to breathe in a synchronized manner. I think it's really wonderful. But Spying with Whales is really such a fascinating book. I was wondering, what do you hope readers get out of it?

Speaker 4

Yeah, this boy, there's a lot of things I hope readers get out of it. One of the big messages I think is that there's amazing aspects of the natural world everywhere. It's not just with whales. It could be with trees, it can be with insects. There's amazing things to know about the world. But how we know about things is really a question that science delivers on in

a real way. And I think science can be intimidating to a lot of people who don't have background in science, or maybe didn't like science in school, or just don't really get it. And what I really wanted to do in the book was to tell stories about how we know, and to tell those stories by way of telling the people involved with them, so that the stories of science become stories about people because people are doing the science. You know, science doesn't happen in a vacuum, and that

science is not straightforward and cookbook like. It happens serendipitously. It happens from a lot of hard work. It can be random.

Speaker 1

So there's all.

Speaker 4

These unusual aspects about how science has done that I think people may not appreciate, and that the way to share those stories is to share those stories of discovery as in a biographical way. So that's really something I try to do in the book was that a narrative about science is really a narrative about scientists. If that makes any sense.

Speaker 3

It does, so, you know Mego and I both found this book to be so delightful. I hope our listeners will check it out. It's called Spying on Wales, The Past, Present and Future of Earth's most awesome creatures, and it's on shelves everywhere. But Nick, thanks so much for joining us today, No problem, happy to be here.

Speaker 1

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Speaker 3

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