Quirks and Quarks - The reason chimps can reason, and more…

Episode Date: January 16, 2026

We may share a common ancestor with chimpanzees, but somewhere along the evolutionary line to us, our brains took a major detour. New research suggests that chimpanzees can rationally weigh evidence, a trait that used to be thought as uniquely human.PLUS:Why penguin-eating pumas live closer together in PatagoniaAnts sacrifice the strength of individual workers for quantityMapping the landmass beneath Antarctica's massive ice sheetHow deep sea ocean environments affect fish body shape

I am an actor, fresh out of theater school with big dreams and an even bigger drug habit. But things are pretty good. That is until my best friend is set up on a date with David Lee Roth. Yeah, from Van Halen. If you know, you know. From CBC's personally, this is Discount Dave and the Fix. The true-ish story about how a fake rock star led me to a real trial that held up a mirror to me. And okay, let's just say that not everyone in this story is who you think they are.

Personally, discount Dave and the Fix. Available now on CBC Listen or wherever you get your podcasts. This is a CBC podcast. Hi, I'm Bob McDonald. Welcome to Quarks and Quarks. On this week's show, mapping the landmass under Antarctic ice. Where there are mountain ranges, before we kind of knew from these radar surveys, but now we can really pick out all the crests and bridges and valleys.

And the expendability of one social insect among many. As the individual becomes part of a more and more complex society, the individual doesn't necessarily get more complex. In fact, it may get simpler and cheaper, so to speak, because it has to do less on its own. Plus, solitary pumas now in the company of others, the peculiar shapes of deep sea fish and rational chimpanzees. All this today on Quirks and Quarks and Quarks.

In Argentina's Patagonia region, Pumas used to be the apex predator. But as the story so often goes, about 100 years ago, when humans came through, establishing sheep farms in the region, they wiped the Pumas out to protect their flocks. And with the big cats gone, certain smaller animals, like Magellanic penguins, thrived in their absence. But in the past few decades, thanks in part to some strong conservation efforts, Pumas have made a comeback. And recently, researchers studying the effects of this rebound noticed that the recovering Pumas have changed their diets, preferring to feast on penguins and adopting some unusual behaviors along with it. Dr. Mitchell Sorota is an ecologist at Duke Farms in New Jersey. He was part of the team.

Hello and welcome to our program. Hi, thanks so much for having me on. First of all, tell me about the Pumas. What led to their populations rebounding? Yeah, so there was some really strong conservation efforts down in the region in the past several decades. As farms have become less productive, they've been purchased by conservation NGOs like Tompkins Conservation and sent over to Park Service for management. And over time, these Pumas have naturally recolonized these areas where they're extracurated from and their populations have rebounded. Oh, so the Pumers just came back on their own, no captive breeding or anything like that.

Exactly. No captive breeding, no retroductions, just passive rewilding. Do you know how many Pumas are there now? No, we don't have a good number of the exact population size. What we were doing for this study was actually looking at density, specifically density around the penguin colony itself. So we found that there's 13 pomas per 100 square kilometers. 13 per 100 square kilometers. That's not very much. For Pumas, it's a massive amount. It's actually what we believe is the highest population density of Pumas across their entire range.

You can find Pumas all the way from Canada, all the way down to South America. And there have been several studies looking at population densities of Pumas across their range. And we believe this is the highest population that's ever been documented. Now, historically, before they were wiped out, what were the Puma's eating? So Pumas across their range can consume up to 200 different different. species. So it's not really surprising that they have different diet shifts across their range. Across Patagonia, Pumas specialize on Guadankos, which are a large llama-like herbivore. But as Pumas came back to Montalien, they switched to praying on penguins.

Now, why was it such a big deal that the Pumas were eating penguins? It's actually not. So to us, at first glance, you know, it's an interesting natural history, note that Pumas are preying on penguins. So it's not surprising to us, but really what matters here is the impact of this interaction. This new food source is really shaping how Puma's move across the landscape, how they interact with each other and their population size. The penguin colony is a small area on the landscape. It's only a two-kilometer stretch of beach, but it's an extremely abundant prey source

for Puma. So it's really shaping how they're moving across the landscape. because there's one fixed point source for prey that the pumas need to be going back and forth and concentrating their movements around this one small area. Now, is it unusual for pumas to be interacting with each other? Yes, actually very unusual. So pumas are what we believe are classically solitary predators. They have wide-ranging movements where they defend our territories.

So these classic solitary carnivores that we often think of, not very social beings. But this really abundant food source allows them to relax their territory, relax aggression, so that they can share this abundant and concentrated food source. Wow. So were they actually cooperating with each other to hunt penguins? They're not cooperating in a sense. It's very easy to hunt a penguin. Penguins aren't well adapted to evading terrestrial predators. So they're pretty easy prey for Pumas. But you can think of it almost in a bear analogy. Bears and salmon are a familiar example of how food can bring predators together. And a penguins appear to be doing something similar for Puma's creating a hotspot that changes behavior across the landscape.

Oh, I see. So the animals were sort of tolerating each other rather than just cooperating. Exactly. Well, how did you look into this interaction further? Yeah, so my first field task was to go down there in late 2019 and set up a camera trap array. across the entire park, and really the intention was never to better understand this interaction between Pumas and Penguins. Really what we wanted to do was surveyed Kuma population following decades of restoration at this site. But immediately it became obvious that this Kuma penguin interaction was much larger and much more important than we get previously thought.

So immediately in the camera traps that were adjacent to the penguin colony had really high detections. of Pumas near this penguin colony. So every day we would go and check those cameras and we would see multiple detections, multiple images of Pumas on these camera traps. Well, what were they doing? How do you hunt a penguin? This is a penguin colony where there's 40,000 breeding pairs.

So that's at least 80,000 individuals at a given time. So it's a really concentrated, really abundant prey source. And these penguins, they're not well adapted to evading. treasure predators. So really, what the Pumas do is they walk up and they snatch them. Easy pickings, in other words. Exactly. So what downstream effects do you think this could have for the whole ecosystem? Yeah, the next step of this research is really to understand what these

behavioral changes mean for the rest of the ecosystem, especially Gwynakos, which are the primary large herbivore across Patagonia. Because Pumas and Guinacos form the dominant predator prey relationship in the region, changes in how Pumas move and hunt. could change how Guanacos are moving across the landscape, how they're foraging, and that can have important implications for the restoration of this ecosystem. Is there a danger that the penguins could be wiped out by the Pumas? So far, the penguin population at this site appears either stable or increasing since the park was established. Yeah, 80,000 penguins, 13 Pumas. That's not a big impact, I guess.

No, not yet. What's the take-home message here for conservation? Yeah, our study shows that restoring wildlife in today's changed landscapes doesn't simply rewind ecosystems to the past. It can create entirely new interactions that reshape animal behavior and populations in really unexpected ways. Well, it also seems to underline the importance of keeping top predators in an ecosystem. I'm thinking of the wolves in Yellowstone example.

Yes, absolutely. we're finding that these change ecosystems don't necessarily have the same effects that we expect them to once we restore them. What was it like for you working in a place like Patagonia? It was incredible. You know, I've had some of the most beautiful, solitary moments and it's a stunning place. I have a higher recommend it was in it. Were you ever worried that the Pumas might look at you as lunch? No, you know, I've only,

You know, there's, again, like this is truly the highest density of pumas that we've know of in the world. And I only saw them a few times. They're pretty skittish. Pretty much every time I saw one, it was running away from me. It's one of those situations where they're more scared of us than we are of them. Well, that's a good thing. Yeah. Dr. Sorota, thank you so much for your time.

Thank you. Dr. Mitchell Serota is an ecologist at Duke Farms in Hillsborough Township, New Jersey. When was the last time you changed your mind, based on new information you received? This ability to rationally change our beliefs, when presented with stronger evidence, was always thought to be a uniquely human trait. But according to new research on chimpanzees in Uganda, that is not the case. It turns out chimpanzees can rationally weigh evidence. So naturally, we, as rational beings, are going to have to change our beliefs

about humans being the only animals on Earth who can pull off this cognitive feet. These findings cannot only give us a new perspective about rationality in non-human primates, but it can also help us better understand ourselves. Dr. Jan Engelman was part of the study. He's an associate professor of psychology at the University of California, Berkeley. Hello and welcome to our show. Hello, thank you so much for having me. How surprised were you when you realized that chimpanzees are also capable

of changing their minds when presented with new evidence? Yeah, well, I would say partly we were very surprised by these findings. We predicted that chimpanzees would be able to actually change their minds in light of better evidence. What we had not predicted is that chimpanzees would also be able to reflect on the evidence. And yeah, this was a finding that really came as a surprise to us because it's especially this ability to reflect on the evidence and to think about what counts as good evidence. and what counts as bad evidence that has been seen as human unique for a very long time.

Now, when you say, reflect on the evidence, say, well, okay, here's some evidence, here's some other evidence I'm going to change. I thought it was this. Now I'm going to decide that. It's even a little bit more complicated than that. So what you just described are two pieces of so-called first-order evidence. So that's just evidence that speaks in favor of a belief. But what we could also show is that chimpanzees respond to so-called second-order evidence. So that's evidence about the evidence. That's evidence, for example, that shows you that your first order evidence is misleading. And chimpanzees even managed to respond appropriately to this kind of second order evidence.

And that was a big surprise to us. How did you get them to weigh evidence against evidence? This was the maybe really exciting part, or the most exciting part, I would say. So here we gave them an indication that the evidence that they had, first received based on which they had already formed their belief and made a choice that that evidence was actually misleading. So let me give you an example. The food was hidden in one of two boxes. We shook the box and they heard a noise there and they had picked that box based on that noise. But then a while later, maybe 20, 30 seconds later, we showed them that there was actually

a stone in that box that could have caused that noise. And when they saw this, when they saw that there was a stone in this box, they changed their mind and picked the other box. Wow. So what went through your mind when you saw that? Yeah, to be honest, I mean, these days as scientists, we are very worried about replicability, right? So we really want to make sure that our results are robust. We really want to make sure that our results, that Chimese's successful performance, for example, in this case, is really due to them thinking about the second order evidence rather than due to some other feature of our task. So at first, I wasn't 100% sure whether these results were real.

But then what we did is we looked at this behavior of chimpanzees in a number of different contexts, and we again and again found the same result. So only when we had this reliability from different contexts that I really start to believe that this was true. And, yeah, I'm still thinking about it today, I must admit. The really big question for me is how do chimpanzees do this? How do they think about evidence? And this is, I think, a big question because philosophers and cognitive scientists, they have argued for millennia that you need language in order to think about evidence.

So, you know, when we think about evidence, we might say something like, well, Bob told me that the best restaurant in town is an Italian restaurant. but how reliable is Bob really as a source? Can I really trust Bob here? So this is how we reflect on evidence. We need language for it, and it's actually quite complex. So how are the chimpanzees making these decisions without language? I don't have a good answer to that.

So I would say our working hypothesis is that chimpanzees have some kind of imagistic representation. So this is thinking with images instead of thinking with work. What's especially hard to represent without words seems to be a word like because. So how does the chimpanzee represent? I believe that the food is in the left box because I heard it there. So how do you represent or think about because using just images? That's a big question. So what does this say to you about the nature of reason since we humans aren't the only ones with this skill?

Yeah, well, I would say it tells me two things. Someone is rational insofar as they respond appropriately to reasons. That, for example, they change their mind when they're presented with better reasons. So humans are rational animals. They are the only animals who can respond appropriately to reasons. So I think what our studies show is that it's not quite that simple. Also, other animals show certain forms of rationality. And the second thing is that you can of course still think about,

is there something that's still special about rationality and about reasoning in humans? And I would actually say that there is. And that's the fact that our reasoning and our rationality is so often social. So as humans, we cannot only reason on our own, but we can actually reason together with others. And this kind of, you could call it social rationality or social reasoning is, I think, something that you don't see very often in the animal kingdom. We often have a misconception of what reasoning and rationality is like in humans, because we often think of it as an individual attribute. Human thinking should be thought of as a social activity. We are particularly good,

and we are particularly rational thinkers, when we get to think in the company of others. What do you make of your findings today when misinformation is abundant? Do you think we're less swayed by facts than chimps are? So I must say that I'm not such a fan of this portrayal of humans as being so irrational. I think most of the decisions that we make on an everyday basis are extremely rational decisions. But it is, of course, true that in certain contexts, humans show certain irrational biases. And these tend to be contexts where our so-called group biases come into play. So these are contexts where, for example, we know what our group beliefs, what our group thinks,

what kind of values our group has. In these kind of contexts, we are sometimes not quite as rational as we think we are, because our main motivation is to align our beliefs with our group beliefs rather than to align our beliefs with the truth. So I guess one of the lessons that might come out of this study is that when it comes to making decisions, follow the evidence. 100%. That's always a good rule to follow. Dr. Engelman, thank you so much for your time.

Thank you so much for your interest. Dr. Jan Engelman is an associate professor of psychology at the University of California, Berkeley. Though our ability to reason may have come from a common ancestor with the chimpanzees, somewhere along the evolutionary line to us, the development of our brains took a major detour. Q R X, T-U-B. Human brains are about three times larger than chimpanzees, a lot more dense, and connected in areas of the brain that really matter for our ability to reason. In another recent study, scientists have identified a genetic switch that acts like a dimmer that can dial certain gene activity up or down, impacting the type of cells our brains make. Dr. Miles Wilkinson led the team that made the discovery.

He's a distinguished professor in the Department of Obstetrics and Reproductive Sciences at the University of California, San Diego. Hello and welcome to Quirks and Quarks. Nice to be here, Bob. First of all, tell me about this genetic switch. What made you focus on that? So basically, the technical term for this switch is a transcriptional enhancer or just an enhancer. So about 2% of our genomes encodes protein.

And originally it was thought that most of our genome is involved in encoding the proteins that make us what we are and make all the cell types in our bodies what they do. But it turns out only 2% of our genome encodes proteins. And a big question is, what does the other 98% do, which is another interest of mine. And one of the things that that other 98% does is it basically regulates. the protein-coding genes. So little volume controls that control, you know, I guess you could, an analogy would be a symphony where the players are the protein-coding genes and the conductors are these enhancers. Instead of one conductor, there are many. And it's very critical when the protein-coding genes are turned on and off during development or, you know, when you're doing

certain activities even as an adult. So basically, this sequence that we focused on is one of these transcriptional enhancers. Well, walk me through. What does this enhancer do with regards to brain development? So what we discovered is that this little 400 nucleotide piece of DNA is critical for forming the precursors of neurons called neural progenitors. And it's not absolutely required, but it greatly increases the efficiency of neural progenitors. Right. Does this switch have a name? Yes.

It has kind of, I suppose, a boring name, but at the same time an easy to remember name, Har 1, 2, 3. Well, so what made you suspect that this Har 1,2, 3 was involved in what makes human brains different from chimpanzees? we picked out of the list of 3,000 of these human accelerated regions, or HARS, as they're called, this particular one called HAR-1-2-3, because it was in a gene that we knew was important for brain development and brain function. And so our thought was that this sequence could be controlling a pathway important for brain development, and that it did so differently in humans and chimps. And you mentioned in the introduction that our brains are three times bigger than a chimp brain.

And so, for example, it could be involved in that. It could be involved in any of a number of other differences that we have from chimps in terms of brain function. How did you test this out? So essentially, we're comparing the same cells, but either with R1, 2,3, without it, or with the chimp version. And when I say with Har 1, 2, 3, I mean the human version, because these are human cells. And we saw differences. For example, they differed in the ability to form norepigendors, the human versus the chimp versions.

They also differed in their ability to form the two kinds of cells that these neural precursors make. One kind is neurons that, you know, a person on the street would be familiar with that. But another very important cell in the human brain are called glial cells. About half of the cells in our brain are glial cells. They're not neurons. And the ratio of neurons to glial cells is critical for normal brain function and is altered in human diseases. What we found is that Har 1-2-3 is critical for determining that ratio. And it's changed basically when you don't have R-1-2-3.

So are you saying that this Har-1-2-3, this conductor, is, of the orchestra, as you say, if it turns on, then that causes the brain to develop more neurons, which means more brain, more thinking power? It definitely, according to our experiments, promotes formation of neurons. Yes, it's likely that that would have profound impact on the brain, but we don't know exactly how. If we compare the human and the chimpanzee brain, are there areas that we have more of that they don't? where this gene could have, or this switch could have been involved? When it comes to the brain, we share a lot of abilities with chimps, but we also have differences.

Just to think about what we share, chimps have emotions, a range of emotions, jealousy, joy, fear, just like humans do. They're capable of communication, of course, as are many animals, or most higher animals. But where we differ, I'd say, well, one obvious one is language. Humans have an incredibly complex language. And at least as far as we know, chimps really have a fairly rudimentary ability to communicate compared to humans. And so Har 1, 2,3 could play a role in that. Another thing that I think would be very exciting if Har 1,2,3 was involved in, is abstract thought. So humans are, as far as we know, unique amongst all animals on earth in being able to think abstractly.

It is an example for your listeners. The Statue of Liberty, if you think of it concretely, it is a statue. But what it represents it, what it means is abstract. And humans are uniquely able to comprehend that kind of thing. and chimps are as far as we know are not able to. So it could be that that Harwan Truth plays a role in that. That would be very exciting, but we have, you know, of course, no evidence at this point. A key question would be, are humans better at cognitive flexibility than chimps?

Kind of going back to the original hypothesis about HARS, the original hypothesis is that Hars confer human specific traits. It doesn't have to be brain traits, but I'd say most of the interest in the field are brain traits. So a natural thought from our experiments is that, well, maybe Har 1-2-3 is critical for cognitive flexibility because it confers the better ability of humans to be flexible than chimps. Because after all, we're always acquiring so much information just from social media alone, for example, that, you know, much more than chimps do. Could there be more switches like this that can impact human brain development?

The way I would think of it is there are three main genetic ways for the human brain to have evolved. One is what we've been talking about, which is a change in gene regulation. But a second way is to change the sequence of the protein coding genes so that the proteins that are produced are a little bit different. And they might work better or worse in a human than a chimp, for example. and that that could make our brains different. And then a third way is through human-specific genes. Now, for the most part, our genome is very much like a chimp genome. I think the usual figures are 99% identical in sequence.

And that means we also have largely all the same genes as a chimp has. But there are a few human-specific genes, very few, maybe a handful. And there's been some interesting studies suggesting that those new genes that have evolved since the split from chimps play a role. So I think all of these together are going to contribute towards ultimately driving the formation of the human brain. So we are different, but not so different after all in many ways. Yeah. Dr. Wilkinson, thank you so much for your time. It's a pleasure to be here. Thanks for inviting me.

Dr. Miles Wilkinson is a distinguished professor in the Department of Obstetrics and Reproductive Science. at the University of California, San Diego. I'm Bob McDonald, and you're listening to Quirx and Quarks on CBC Radio One and streaming live on the CBC News app. Just go to the local tab and press play wherever you are. Coming up later in the program, the Deep, Dark Ocean's influence on body shape. We think of body shape as being really important in aquatic systems for reducing drag.

But that's only if you're trying to move through the water, and these fish really are doing a whole lot of moving. If you sold somebody a loaded gun who you knew was in a vulnerable state and they shot themselves. I think it is murder. Just because you're using the internet doesn't mean you get away with murder. I'm Damon Fairless, host of Hunting Warhead. This season, I take you inside the business of suicide and the places desperate people go when they can't find what they need in the real world.

Hunting the Suicide Salesman. Available now wherever you get your podcasts. chances are at some point in your life you've pondered the trade-offs between quantity and quality. Should I book a two-week getaway in a luxurious villa in Tuscany? Or for the same price, maybe I'll enjoy multiple weekend trips closer to home. Well, it turns out that in the animal world, similar competing forces are at work. Take sea turtles, for example. Only one out of every thousand hatchlings will make it to adulthood.

You can do it? Whereas mammals mostly only have a few offspring that they spend months, even years, nurturing. But reproduction isn't the only arena where we find this competition between quality and quantity. Take social insects like ants, for example.

What allows an individual ant to thrive isn't necessarily the same thing that makes an ant colony thrive. So from an evolutionary point of view, there's a trade-off between what's good for the individual versus what's good for the colony. Well, a new study looking at how rugged each individual ant is compared to the size of their colony, has uncovered an intriguing example of this. Dr. Evan Economo is an entomologist at the University of Maryland and is one of the authors of this study. Dr. Economo, welcome to Quarks and Quarks.

Thank you. Thank you for having me. What were you hoping to understand in your study? Well, we wanted to understand the evolution of this really critical trait, which is the cuticle of insects. So insects, they have this exoskeleton like this armor over them, and that mediates their interaction with the environment in many different ways. And specifically, when it comes to ants and other social insects, you get a lot of interesting tradeoffs between how the colony will build an individual versus build colony level structures and phenomena. So we want to understand how cuticle thickness evolves along with sociality. Well, how does cuticle thickness or how rugged an ant is vary from one to another? So it varies quite a bit across species. So some species it may make up only a few percent of

their body volume, and then at the high end it can go up to nearly 40 percent of their body volume. So different species are armored in different ways. And One thing I like to say is any little kid who's played with ants in the yards may have already discovered this. So I think informally that this study is kind of like the evolution of squishability. Squishability. I was thinking more like, you know, just walking around in shirt sleeves compared to wearing full football gear. Yeah, yeah, it's kind of like that. I want to be clear I'm not advocating for squishing ants on other insects.

So then how did you go about studying how the thickness of an ant's cuticle or its armor is related to the ant colony? Yeah, well, we used a technique called micro-CT, microcomputed tomography. And this is very similar to a CT scan that a human might have in the hospital only at much, much higher resolution. So basically what we were doing is CT scanning ants. And then once you have that CT scan, you can calculate. using computer vision algorithms, how much of the body volume is taken up in cuticle. And you say that there's quite a range of difference. So how does that affect the ant's behavior? Yeah, well, it affects quite a bit how much it costs to make an ant. So cuticle is a very,

it's an expensive tissue. It takes a lot of nitrogen. So it's a different kind of investment in the ant. And also how it affects how ants may behave. Well, well, it makes them much, more vulnerable to damage much less hardy. They have a thinner cuticle, but it also may have other advantages like make it easier to expand parts of their body to store food, for example. So how did you see the relationship between the thickness of the cuticle and the ant colony? Yeah, we CT scanned over 800 individuals, over 500 species, so we got this data across many, many different species of that. And then we basically did what's called a comparative analysis where we did statistical methods to understand what other traits evolved along with this

variation in the cuticle. And what we found is the dominant driver was colony size. So species with large colonies actually tend to have thinner cuticles. So that is what indicates it's involved with this trade-off. So why do you think that is, that a larger colony would have thinner armor? I think it's a strategy that is, again, relates to this quality versus quantity trade-off. If the colony has to do certain things, it needs to find food, it may need to attack prey, it may need to build a nest, and may need to do all kinds of things like that. So the trade-off we see is that larger colonies are taking a strategy where they're investing less in each individual. So it relates to some ideas in social evolution that as the individual becomes part of a more

and more complex society, the individual doesn't necessarily get more complex. In fact, it may get simpler and cheaper, so to speak, because it has to do less on its own. So really, it's strength in numbers here, that they can subdue prey or do work, even if any individual's less robust. Oh, I see. They don't need to be as tough because there are lots of them, so they have safety in the numbers in the colony. Exactly. And individuals are expendable in a social insect colony in a way that they're not if they were solitary organisms. In these large colonies where you have the ants that are not as well protected, would you say that they're sort of working for the greater good of the colony? Yeah, I mean, I think in all of these ant colonies, individuals are working

to some extent, to large extent, for the greater good, although it just so happens that their own interests are aligned with the greater good. I mean, they need the queen to reproduce in order to pass on their genes. But you do see in ants and in social insects much less, let's say, risk aversion for an individual and for that reason, because individuals are more expendable. And that's probably why in these species that have thinner cuticle, you know, there may be more vulnerable. If there's a battle, many of them may die, but it's still more efficient for the whole colony. Because there's so many of them. You can lose a few. Yeah, there's so many of them. And even in battles, even in the military, for example, in naval battles, they have similar

questions like this, do you want to produce many ships that are smaller and less robust or a fewer, larger, more, you know, more expensive ships? And that's in a battle, it's not always better to have fewer, better, sometimes having more is, but is more advantageous. Do we see tradeoffs like this elsewhere in the animal kingdom or are ants special because of their highly structured societies? Yeah, I think these kinds of tradeoffs in terms of quantity versus quality are all over the animal kingdom, certainly in reproduction of individuals, how many propagules you're putting out there is, and I think you mentioned in your introduction, fish versus mammals. That's a very classic contrast, for example, in reproductive strategies. I'm also thinking in humans, the difference between a farming community and a city. where the farmers have to do a lot on their own,

so they tend to be nice and strong, and people in the city can have jobs that don't necessarily require fitness. Yeah, absolutely. So that's one reason why scientists like me are interested in ants and other social insects because it's an independent evolution of complexity, social complexity, and it's an interesting parallel for understanding what happens with humans. But in both cases, what you see is as we live in more complex society, it allows division of labor, which can be much more efficient.

So you can imagine we can specialize on certain things, but not have to do everything and not be good at everything. Dr. Economo, thank you so much for your time. Yeah, thank you. Dr. Evan Economo is an entomologist at the University of Maryland in College Park. These days, we take maps for granted. A few clicks on your smartphone and you can see a map of your neighborhood or any other city just about anywhere in the world in amazing detail.

But we've mapped some parts of the world a lot better than others. And one area that's been rather neglected is Antarctica. Now, most of Antarctica is covered by ice, and we know what that ice looks like, thanks to aerial photography and satellite imagery. But figuring out what's under the ice has been a much bigger challenge. Well, now scientists have finally done it. They constructed the first detailed map of Antarctica's landmass.

Dr. Helen Okenden is a climate scientist at Grenoble Alps University in France and is part of the team that made this new map. Dr. Okenden, welcome to Quarks and Quarks. It's great to be here with you. Now, prior to your study, how much did we know about the terrain underneath these ice sheets in Antarctica? So traditionally, the way we've looked at the landscape beneath the ice is using radar, surveys. So that's radar equipment that's suspended underneath a plane or towed along behind a skidoo. And those surveys, they take a 1D cross section of what's beneath the ice. So we can see

what's exactly beneath the skidoo or the aeroplane. But it didn't really tell us what was on either side. And traditionally, these surveys, they've had gaps between them of five or ten kilometres. So we had really good information every ten kilometres, but not really any idea of what was in between them. How thick is the ice in Antarctica that you're trying to see through? So the average thickness of the ice is about two kilometers, but there are places where the ice thickness reaches more than four kilometers. So it's pretty thick. Wow. Well, tell me about how you went through figuring out what is actually underneath the ice. So in some areas where we have really dense radar surveys that do give us a sort of 3D idea of what's happening in the landscape

just for 10 or 20 kilometres, we often see that there are patterns in the landscape which are kind of echoed in the surface of the ice. So that's a little bit like if you're canoeing in a river and there's a rock beneath the surface of the water, often you see eddies in the surface of the water, which kind of indicate that the rock is there. And ice, it flows very differently to water.

It's much more viscous. But again, as the ice flows over these rock features hidden beneath, it leaves an imprint in the surface of the ice. ice. So what we've been able to do is using modern satellite images of the surface of the ice, which tell us about these sort of echo features in the surface of the ice everywhere across the whole continent. We've been able to combine these satellite maps with what we know about the mathematics of how the ice flows over these hidden features, and use that to map what's happening in the landscape beneath the ice everywhere. So not just where we have the survey lines, but also

filling in those gaps between them. Oh, I see, because the ice is like glaciers. It's actually slowly moving like molasses downhill. And so you're looking at how it's moving to tell what it's moving over. Exactly. Even though traditionally you might think of ice as being very solid and stable and not moving, when you have a big mass that covers an entire continent, then it flows under its own weight like glaciers in mountain ranges in Alaska or the Alps in Europe.

and then because of the flow of the ice, we see these features, these echo features appear in the surface. So once you finally map the contours of the ice on the top, what kind of landforms did you see underneath it? So Antarctic is an entire continent, so we see a whole range of landforms. But some of the things that we're really excited about are where there are mountain ranges.

Before we kind of knew from these radar surveys where the mountain ranges were, But now we can really pick out all the crests and ridges and valleys in those mountain ranges. I'm not just in the big mountain ranges, but in smaller highland areas as well. And some of these highland areas, they're regions where the ice in Antarctica has thought to have initiated as mountain glossiers before spreading out to be the entire continent nearly 40 million years ago. So those are really interesting areas, which we're very excited about. Wow. Another thing that we found is these incised channels underneath the ice, which are probably where water is either flowing now or has flowed in the past. So they're sort of really interesting signs about the hydrology that's going on as well. Well, what was it like for you to uncover Antarctica and actually see a land that no one's ever seen before?

For me, I think it's really awesome. It's kind of mind-blowing to look at this math and see all these new features and how, everything's connected, sort of discovering new worlds underneath the ice, I guess. Well, you're kind of following in the footsteps of the great explorers of Antarctica, like Amundsen, who are just trying to reach the South Pole, but you've gone through the ice. I'm not sure I'd go that far, but maybe. Why is it important to study the landforms of Antarctica so clearly? So aside from the fact that it's really cool, it's important to know what's happening

what the topography of the landscape is like beneath the ice because it's a critical boundary condition for our models of how the ice sheet moves and how it's going to change in the future and those models are the models which are used to make projections of sea level rise and those are the projections which policymakers, governments, towns, cities

are using to consider how they're going to tackle sea level rise in the future. So if you want to build a seawall, you need to know how tall that seawall needs to be, where to put it. And in these models, we're really limited by a lack of knowledge about what's going on beneath the ice. Just one last thing. Have you been to Antarctica in person? So during my PhD, I spent three months there actually carrying out one of these radar surveys. So we were there for three months and we surveyed what is a tiny postage show.

stamp compared to the size of Antarctica. So an area approximately the size of Glasgow, Antarctica is like the size of the whole of Europe. And that took us three months. So what's that like to be there looking out over this vast icy landscape that looks pretty flat on top, knowing that there are all these mountains and valleys underneath your feet? Yeah, so it's actually really interesting because the landscape, it feels very flat. But if you're kind of attuned to them, You do feel these subtle variations in the surface of the landscape. So if you sort of know what's kind of might be underneath and then you feel the subtle variations, I don't know.

It's really interesting in the context of this method to have that real world what it's like in Antarctica. There were some days where the sky was white and the snow was white, everything was white. It's just a completely different experience to anything else. Dr. Arkin, thank you so much for your time. Thank you for having me. Dr. Helen Okenden is a climate scientist at Grenoble Alps University in France.

When we talk of exploring the Great Unknown, you might imagine a spaceship hurtling into outer space, but there's a great unknown right here on Earth, too, the deep, dark ocean. It's the largest habitat on Earth. Oceans cover 70% of the surface, and 90% of the ocean is in the deep sea. the area between 200 meters and 10 kilometers deep. Getting cameras or eyeballs to the very bottom of the deep ocean is expensive and tediously slow.

We've only seen less than 0.001% of the seafloor, leaving a lot of unexplored territory and species yet to discover. But that didn't stop a team of American scientists from investigating the diversity of fish in the deep sea from the species we do know about. They looked at nearly 3,000 species of fish of all sizes and shapes to understand how the depth at which they live influences their body shape. It turns out there's a pretty stark difference between the deep sea fish that live in the open water and the ones on the ocean floor.

Dr. Elizabeth Santos led the research. She's an assistant professor in the Department of Evolution, ecology and organismal biology at Ohio State University. Hello and welcome to our program. Hi, thank you for having me. First of all, how diverse are fish body shapes as you go deeper into the ocean? Deep sea fishes are actually one of the most diverse groups across all fishes when it comes to body sheep.

And this is pretty surprising for a number of reasons. So when you think of the ocean, the images that might come to a lot of folks' minds is a place like a coral reef where you might go snorkeling. And a coral reef has a lot going on. And so it would be unsurprising to see a lot of body-shaped diversity in a place like that because there's just a lot to do. But you contrast that with the deep sea. What you get is a place that's totally dark, a wide expanse of ocean with not a whole lot going on. And yet you have this massive diversity of body shapes. And this is something that scientists have only come to realize quantitatively in the past five years or so. And it's because we have a critical mass of these museum specimens to measure

body size from. Well, give me some examples of some of the shapes you see on the sea floor. The most typical shape is going to be something like a tadpole shape, which isn't something we see a whole lot in shallow water environments. And so most recently there was a lot of news pieces about a species of snailfish that was recently discovered. And so if you Google this snailfish, it's actually really cute. It's a pink fish. And it's got this big head and a long tail. And it looks sort of like a tadpole.

So that shape is actually pretty common across deep sea fishes as you get closer to the seafloor. Okay. Now, how does that compare to fish that are higher up? So we call fish that are higher up in the water, pelagic. Pelagic means that they spend their lives surrounded by water in all directions. Deep sea fishes in the pelagic realm have the full gamut of body shapes that you can imagine. Most folks would be familiar with anglerfish from the famous scene and finding Nemo where Nemo somehow makes it to the deep sea and then finds this predatory anglerfish.

So it's sort of a round blobby thing. But the exact opposite of that spectrum is something. something called a snipe eel. And a snipe eel is a very thin elongate fish. So snipe eels actually have the most individual vertebrae in their spinal column of any animal. And so those are the two extremes, round blobby and very thin and elongate. And you see everything in between. So what about the fish on the very bottom? So they live a pretty different existence. So on the bottom, those fish are actively swimming. They're cruising just above the seafloor. And they're looking. down and they're looking for prey that's on top of the seafloor buried in the sediments.

They might have to go quite a long distance to find something to eat. So unlike the angler fish in the water, they are actively searching for prey. It seems a little bit unintuitive, but that tadpole shape actually helps them move through the water because it's a longer surface area to beat their tails and propel them forward. And they're searching around in the dark as well. Absolutely, yeah. So can these different body shapes and swimming patterns tell you anything about how differently these fish evolved depending on the depth?

Absolutely. So that's one of the big takeaways from our study is that depending on where they are in the context of the deep sea, they're evolving in pretty different ways. It turns out that tadpole shape's actually a pretty good shape to have if you're in that environment because, again, it helps you cruise. It helps you look around for food that's on the body. bottom. And so a lot of fishes evolve towards that shape, which reduces the diversity of shapes you see overall because it implies that a shape that is not that tadpole shape is going to be less suited

to that environment. Whereas you go higher up in the water column, you're doing a whole lot less swimming in that case because you're typically lowering prey to you with those bioluminescent lures. since your prey can be coming from all directions, it's a whole lot harder to be seeking out. So you're going to be swimming a lot less. That means your body shape can be pretty much anything. We think of body shape as being really important in aquatic systems for reducing drag.

But that's only if you're trying to move through the water. And these fish really are doing a whole lot of moving. The fish higher up are living in a three-dimensional environment where food is all around them. They don't have to chase it. Whereas on the bottom, they have to seek it out in the mud. That's a great analogy, thinking about it as a three-dimensional environment

versus a two-dimensional environment. Now, what about the sort of how quickly these different types of fish evolved? Yeah, so this is another exciting finding from the study. We find that the speed at which fishes evolve new body shapes doesn't necessarily match to the total number of body shapes that evolve. and this is something not very intuitive, but the reason we see this is because in the case of benthic fishes, they evolve towards that tadpole shape often,

and they evolve towards that shape pretty quickly, but they don't evolve towards a whole lot of other shapes. And so the speed of evolution isn't necessarily commensurate with the total diversity, whereas the pelagic realm evolution is a little bit slower, but you end up with a whole lot of body shapes. And so that's a little bit mysterious. So evolution found the best shape and then just stayed with it. Yes, absolutely.

So what are the implications of your study, especially as we race towards unlocking rare earth minerals that could be hiding on the seafloor? People want to mine them. Absolutely. So people are looking more and more towards harvesting resources of the deep sea. And that makes a lot of sense. Again, it's Earth's largest habitat.

That means there's a lot of stuff there. There's a lot of resources. And another thing that I think about in addition to the minerals is fish oil products. So deep sea fish aren't necessarily good to eat. They're full of lipids, so they wouldn't necessarily be tasty. But you can ground them up and make things like fish oil pills or food for livestock. The problem with doing this is this is an environment we know very little about. We know very little about this environment.

we know very little about who eats who or how the organisms are connected to one another. And in the case of the rare earth minerals, which are on the seafloor, we know very little about how destroying those patches of seafloor will affect the organisms that cruise over those areas. And so that makes it a little bit scary, tempering with something you know very little about. Well, if there's less diversity in body shape on the seafloor, does that mean they be more sensitive to being wiped out if their environment was to change. I think that's definitely a possibility because it means they have a very optimized lifestyle, and if you disrupt that lifestyle, there's not a whole lot else that they are equipped to do.

Dr. Santos, thank you so much for your time. Thank you so much. It was great being here. Dr. Elizabeth Santos is an assistant professor in the Department of Evolution, Ecology, and Organismal Biology at Ohio State University in Columbus. And that's it for Quirks and Quarks this week. If you'd like to get in touch with us, our email is Quirx at cbc.ca. You can find our web page at cbc.ca.

slash quirks, where you can read my latest blog or listen to our audio archives. You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play. Quarks and Quarks is produced by Rosie Fernandez, Amanda Bukowitz, and Dan Falk. Our intern is Dion Sudio. Our acting senior producer is Sonia Biting.

I'm Bob McDonald. Thanks for listening. For more CBC podcasts, go to cbc.ca.ca slash podcasts.