Scott Payne spent nearly two decades working undercover as a biker, a neo-Nazi, a drug dealer, and a killer. But his last big mission at the FBI was the wildest of all. Had to burn Bibles. I have never had to burn an American flag. And I damn sure was never with a group of people that stole a goat, sacrificed it at a pagan ritual, and drank its blood. And I did all that in about three days with these guys.
Listen to Agent Palehorse, the second season of White Hot Hate. Available now. This is a CBC Podcast. Hi, I'm Bob McDonald. Welcome to Quirks and Quarks. On this week's show, an appetite for rotten bananas and fun. How fruit flies react when they're given a tiny little playground. Each fly responded very individually to the carousel. Maybe a quarter of them or a fifth went to that platform repeatedly and for very prolonged periods of time. And the romance of scientific research.
how krill researchers found themselves elbow deep in penguin poop. It's a little bit like fermented shellfish. It's not a great smell. You do get used to it after a while, but it's not pleasant. plus seals have a sense of oxygen, baby hummingbirds disguise themselves from predators, and, oh, behave, getting at what dinosaurs really did. All this today on Quirks and Quarks. Dr. Jay Falk has been studying a hummingbird called the White-Necked Jacobin in Panama for 10 years.
So when colleagues came across a nest with two eggs in it, they let him know right away. He and his advisor, Dr. Scott Taylor, went to check it out. Here's Scott Taylor. I was... kind of taken aback by how fuzzy the chick looked because you know I studied chickadees and chickadees the day they hatch we call them gummy bears they're they have no hair they're just pink little very helpless creatures but this
hummingbird looked hairy. And as we approached the nest, it started to shake its head in this way that wasn't begging behavior. It was... you know, really reminiscent to me immediately of caterpillar movement. So it was kind of this just, you know, standing in the Panamanian rainforest, looking at this weird little hummingbird chick, moving its head and shaking its butt and really, you know, behaving and...
and looking like a caterpillar. It was quite shocking, actually. With Dr. Taylor's help and encouragement, Dr. Falk began to investigate why these newborns look so strange. Dr. Jay Falk is a U.S. National Science Foundation postdoctoral fellow at the University of Colorado and at the Smithsonian Tropical Research Institute in Panama. Hello Bob, thanks for having me. Tell me a little bit about this hummingbird. Where does it live? What's it like?
It's the white-necked jacobin, and this species ranges from the southern parts of Mexico all the way to sort of mid-Brazil latitudes. But basically, it's very common in any sort of lowland tropical region. So what went through your mind when you looked into this nest? I was just super excited about this because...
I had actually never seen a nest of this species that I'd been studying for years. They're really hard to find for some reason. And what made it even more interesting was... the type of female that was sitting on this nest. they have what's called a female polymorphism. Now, if you look this bird up in almost any field guide, you'll see that the females...
look one way with sort of drab tones, a mottled throat, and a darkly colored tail. While males are more ornamented, they have this bright blue head and a bright white tail. But the reality is... About 20% of the females look almost identical to the males. The reason why I was so interested in this nest was because it had one of these male-like females on it. And so it was sort of like an extra special net.
So if the female is imitating the male, what do the chicks look like? Right. So this chick was covered in these long downy feathers that were very similarly colored to the nest itself. And at first we were thinking, well, it kind of looks like they might be camouflaging with the nest. But then as we were watching it, as we were kind of getting closer to take a closer look. the chick started rearing its head up and was doing this kind of head shaking or head thrashing behavior.
Usually when you approach any sort of bird nest, they kind of open their mouths and try to get some food. But this one didn't open its mouth and was doing this weird shaking behavior. And we were looking at that and we were looking at the feathers and together we were sort of like, huh, this looks like one of those fuzzy caterpillars that you really don't want to touch.
Well, why would a baby bird want to look like a caterpillar? Yeah, so it's really interesting. So if you walk around the forest here, you'll see sometimes caterpillars that are covered in these hairs. And everyone around here knows that you should not touch those caterpillars. Because oftentimes they can deliver really, really painful things.
So those little hairs will break off and get into your tissue and deliver some venom. And it's just very, very painful. They actually call them chicken killers in some cases. These kinds of things can send people to the hospital because they're so painful. and they cause rashes, all sorts of things. If you saw this, you wouldn't want to touch it. And I think animals like birds and maybe other insects are looking at this and thinking, well, I shouldn't touch that.
Oh, I see. So it's sort of mimicry. I'm mimicking a dangerous caterpillar so you won't bother me. Now, what kind of predators would a baby hummingbird be subjected to? All sorts. You know, a baby hummingbird really is about the size of a caterpillar. And typically they're just completely defenseless, especially when the mother goes out to feed and find food for her chicks. They're just alone in the nest.
and can't really move. So I think almost anything really would be able to eat a hummingbird. Things like small to medium-sized birds could make an easy snack out of a hummingbird chick. But I think also insects, especially predatory insects like wasps are generally predatory. could make a meal out of one of these hummingbird chicks. Well, did you see any opportunity where a hummingbird chick did defend itself against a predator?
Yeah, actually we did. So that first date we were watching this chick, we were just... kind of thinking okay well we'll wait around and see when the mother comes back and all of a sudden this wasp flew up to the nest and was really checking it out And the bird lifted up its head and started doing that head shaking behavior. And eventually the wasp kind of seemed a little bothered and eventually left.
Wow. Okay, so if this imitating a poisonous or dangerous caterpillar is a good defense mechanism against predators, what happens when mom comes back? So by the time the mom came back, the wasp was gone, totally gone. And she just got back and, you know, fed the bird, fed her little baby and sat back down and kept incubating. Well, how does the chick know the difference between mom and a predator? You know, that's really interesting. So it turns out that...
Hummingbird chicks need a little bit of a secret push. to beg for food, to open their mouths. And this is a little different from other birds. It turns out they need a little bit of a touch around the side of their ear. And then they'll know, okay, that's mom. She's here to feed me. They'll rear up and put their head up and then open their mouth for her to feed them. Wow. So how effective is this caterpillar camouflage in protecting the hummingbird chick?
That's a great question. And it's something we don't know yet. So the observations for this study was just from this one chick. And of course, we've looked at some other photographs of chicks online, and it does seem to be the case that the chicks of this species generally have these long hairs. But that's one of the follow-up studies that we need to do to see exactly how effective these hairs are and why exactly did this species grow long hairs but other hummingbird species did not.
So that's a great question for the future. Just one last thing. What was it like for you to see this incredible mimicry in nature? You know, for me, I've spent so little time looking at the chicks. I've been spending all this time focusing on the coloration of the adult.
And so when I saw the chick, I was like, that's interesting, but I didn't think it was too remarkable. And it was actually Scott who was like, you know, there's something weird about this chick. And so we had a lot of fun with this. Like we had these photos on our phone. Any person we could find that would be interested in this, we showed them the photo on our phone and we'd say, what is this? And they'd say, oh, it looks like a caterpillar in a nest.
And we'd be like, not exactly. But yes, that's what we were looking for. Sort of serendipity science in action. Yes, exactly. Dr. Falk, thank you so much for your time. Thank you, Bob. Dr. Jay Falk is a U.S. National Science Foundation postdoctoral fellow at the University of Colorado and at the Smithsonian Tropical Research Institute in Panama. Seals are incredible swimmers. After all, they spend 80% of their time at sea and 90% of that time underwater diving for food.
It's even more incredible when you realize they do this with pretty much the same physiology as humans. A mammal's lungs, heart, and circulatory systems. But if we were to spend the same amount of time holding our breath underwater, we'd be in some serious trouble. Which is why researchers are so fascinated by how seals are able to hold their breath so long.
Now a new study reveals that seals can actually feel the levels of oxygen in their blood, so they know when they need to return to the surface. Dr. Chris McKnight is a senior research fellow at the University of St. Andrews Sea Mammal Research Unit in Scotland. He led the work.
Hello, and welcome to our program. Hello, Bob. Thank you very much for the kind introduction and your interest in our work. It's a great pleasure. Well, before your study, what did we know about seals and their diving abilities? So there's a few really key attributes to why seals are so good at diving. The first part of it is they're very good at storing a lot of oxygen.
And then the other side of it is that they're very good at controlling the rate at which that oxygen is consumed. So they're very good at sort of controlling how much of a sports car or a racehorse they are and then how much... of the time they're a sort of a hybrid car or a tortoise, effectively. Well, how do the seals compare to humans in terms of their diving? I know when I want to take a dive, I'll take a few big breaths beforehand.
get a big lung full of air, dive down and hold it as long as I can until my lungs start burning, which just isn't very long. Yeah, so one of the most interesting thing about seals is, in fact, when they dive, rather than breathe in and begin to breath hold, they actually expel the air from their lungs and tend to dive on empty lungs. And that's because the vast majority of where they store their oxygen.
is instead of being in the lungs, it's actually in the blood and in the muscle. But what's really interesting about them is that in some way they can control their heart rate So we know if a seal is going to die for a couple of minutes, you know, they'll maybe drop heart rate by 20 or 30 beats a minute. But if that animal is then choosing to die for, say,
30 minutes or 40 minutes, in the case of the seals that we work on, a gray seal, they can then drop their heart rate down to as low as four beats per minute. Wow. Well, take me through your work. What were you interested in finding out about this whole process? We know they can store lots of oxygen and we know they're very good at regulating the use of oxygen. But ultimately, you still run the risk of running out of oxygen at some point. So what we hypothesized is that...
We think that they must be able to perceive on some level the amount of oxygen that's in their blood, both whenever it's low, but also whenever it's high. So there's also a benefit to knowing when you have enough oxygen on board to go back under again. So how did you test this on the seals? We'd have the animals surface to breathe in effectively a small dome, a small pyramid.
And so we used that small pyramid the way you would use a face mask in humans to control the levels of oxygen and the levels of CO2 that the animals were inhaling. So after they would inhale, they'd go on the dive and then we'd use the information on the dive. So how long did they dive or how long did they spend at the surface?
to sort of interrogate whether or not the animals were making decisions mainly based on changes that we controlled in oxygen or the changes we were controlling in carbon dioxide. I see. Well, how did you train the seals to come up underneath your pyramid? Yeah, so this is, I think for a lot of animals, this would be quite difficult, but actually for seals, they train themselves effectively. So what we do is we have the fish.
basically somewhere else in the pool that they have to swim to and once they discover that's where the fish are that's sort of very easy to get them to go to they're very very food motivated animals In terms of breathing in the dome where we control the oxygen and carbon dioxide levels, Remarkably, they take to that very quickly.
historically grey seals would have been ice breeders so they're comfortable breathing in a sort of confined space rather than say the open ocean but also remarkably seals they don't like the rain and they don't like the wind and we have No short supply of both of those things in Scotland. And very quickly the animals all make the switch to wanting, preferring to breathe inside the dome rather than the surface of the pool.
Okay, so you've got this tank with the seals in it. You've got your dome over top of it where you can change the oxygen or carbon dioxide levels. How much did you change it one way or the other? So for the oxygen, we would either deliver ambient air, that was our control. And ambient air is 21% oxygen and 0.04% CO2, so very small. And we would either double the oxygen.
Or we would half the oxygen. So we take it from 21% down to 10%. Whereas CO2, we increased it by 200 times normal level. So this was a really... large change in the CO2 levels that the animals would be inhaling. Wow, 200 times carbon dioxide. What would that do if a human walked into that? So I can say from firsthand experience. remarkably unpleasant. So after a very short time in that level, I would say...
You initially begin to hyperventilate, so your breathing rate increases significantly, but you also start to get this feeling of slight unease, slight sort of discomfort, a real desire to breathe. And then eventually it's you really do not want to be breathing that anymore. You want to remove yourself from that situation.
So what did you find out? How did the seals respond to either increased oxygen levels or increased carbon dioxide levels? So really remarkably, 200 times elevated CO2 had no effect on their dive duration. But just doubling or halving oxygen, that drove all of the changes in their diving behavior. So if there was less oxygen, they would dive for a shorter period of time. And if there was more oxygen, they would dive for longer.
But also on the higher end of oxygen, so when they're at the surface reloading oxygen, we find that on lower oxygen, they spent longer at the surface, taking longer to try and reload stores before diving again. So it's oxygen that matters to the seals, not the carbon dioxide. They ignore that and only monitor the amount of oxygen that's in their blood. Do you know how they do that?
Yeah, so certainly in terms of the decisions of how long to stay underwater, that was very much seemed to be driven by the amount of oxygen in their blood. So in terms of sensing oxygen and sensing CO2, our body's continually doing that on a subconscious level. The sensing of O2 or CO2, or certainly in humans, CO2 certainly starts to generate a lot of perceivable feelings. So feelings like I need to breathe or I'm feeling a little bit of risk.
So while in humans, and we think in many mammals, those sort of feelings are much more prominent in CO2, we believe it's the sort of same hardware. but effectively different software that is giving priority in terms of those perceivable feelings towards oxygen rather than CO2 in seals. So sort of inversing. how the software works in humans. Just one last thing. What's it like working with wild seals?
I have to say it really is a privilege and a great pleasure. And there's certainly... in any of these sorts of studies, the decision to work with animals from the wild is never taken lightly. I have to say, working with juvenile animals, as we did recently, if you can imagine the movie Animal House with John Bellucci, it's kind of like that, but with dogs. It's sort of like, I think, really. fun and exuberant animals. And it's always very nice.
to see the animals go back into the wild. But I think for us, there's sort of always a little bit of sadness seeing the animals go back. You know, you sort of wish them all the very best. But it's a great pleasure. And I think it's definitely one of the highlights of my job.
Dr. McKnight, thank you so much for your time. Thank you very much, Bob. It's been an absolute pleasure. Thank you. Dr. Chris McKnight is a Senior Research Fellow at the University of St. Andrews Sea Mammal Research Unit in Scotland. Remember the flea circus? They were a popular form of entertainment in the 19th century. They fell out of fashion by the 1940s, partly because of concerns about animal cruelty.
But what if the fleas were actually having fun? It might just be possible, if fleas are similar to flies, because a new study has found that fruit flies have a propensity for play. Dr. Wolf Hetterut is an associate professor at Northumbria University in the UK and was part of this research. Hello and welcome to our show. Welcome, Bob. First of all, how do you define play in animals, and in this case, insects?
Well, that's a tricky one already because the definition of play incorporates a lot of very, very different behaviors. The general overarching differences would be to differentiate between social play and individual play. And a social play would be everything that is interaction between two animals. So we have the classical dominance behavior, like the rough and tumble play of rats or foxes or dogs.
that we see in every park, basically. Then we have intersexual play that establishes social roles and might define mating success. And then we have the whole side of individual play that incorporates things like object play. That's the classic fetching a ball, playing with a dog, for example. And we also see this kind of object play in other animals, even in bumblebees, for example. There was a study not too long ago that saw that.
And there's locomotor play. That's the classic jumping and running around. And then there's something that we looked at. And that's basically the staple of every playground. swinging, sliding, and spinning, and that is passive locomotion. Well, why did you choose to study play in fruit flies? So that goes back to a seminar eight years ago where we met on a weekend in Konstanz in Germany to talk about intentionality in insects. and what the prerequisites are for intentional behavior in insects.
But in the end, insects live in the same world we live in and they have to cope with very similar. challenges in their daily life. And one prerequisite is that they perceive the world with their external sensors, with vision, olfaction, touch, taste, smell. But to interact with the world, they also need to have a perception of themselves, of their own body.
And this is usually created with their proprioceptors. These are sensors in our muscles, in our joints that give us an idea about how tall we are, what size we are. Do we have a tail? Do we have a trunk? And that's the same is true for insects. They also need to know what dimensions they have to be able to interact with the world. And I was wondering if this kind of play behavior that we see on every playground is particularly suited to train this kind of self-perception of our body.
When you talk about intentional behavior, you mean the insect seems to be doing something, making its own choice and not just sort of being instinctive with normal behaviors. Is that what you mean? Exactly. So when exposed flies... to a carousel, my expectation would be that they completely avoid it, that they would not want to be in this loss of control situation. Why would it be there?
Tell me about your experiment. How did you test this? So we basically built an enriched environment for fruit flies. So we provided them with food and water at libitum as much as they wanted to. It was a 10 centimeter round arena covered with a glass dome. So they couldn't really fly in there, but they could certainly jump around.
And in that 10 centimeter arena was a four centimeter diameter level platform that was spinning at about one turn per second. Oh, one turn per second. That's pretty fast for a fruit fly, isn't it? It can be. So depending on where the fly was sitting, if it was sitting at the outer rim, it could become quite speedy. Actually, it would reach the speed that flies usually would have at takeoff before they fly.
Now you say it's level, so the flies had a choice to either get on this spinning disc or not. Exactly, and the flies were always able to access and leave the carousel at their own volition. So how did the flies react to the spinning disc? Very different. So that was probably one of the most surprising results. There was not one response by the flies.
Each fly responded very individually to the carousel. The majority of the flies didn't want to go there. But there was a subset of flies, maybe a quarter of them or a fifth. that went to the platform repeatedly and for very prolonged periods of time, even across days. How long would they spend on it? Oh, that varied a lot. In one extreme case, we had one fly that was on the carousel for 18 hours, so it must have slept on it, actually.
18 hours. Wow. So they do seem to be enjoying it, acting like they're playing on it. That is the conclusion that we came to, that at least a subset of them seems to enjoy the ride. I'm just wondering, if you put a microphone in there, could you hear them going, whee? That is actually a thing. Some people, they do these kind of studies. They listen into the flies. vibrations and the sounds they make. So theory could do that. Okay.
Now, you mentioned that bumblebees play. They play with balls and things like that. Why do you think play is so important in insects and animals, including us? That is a really big question because we see it. We see it across a whole range of species, in mammals and in birds. But there are even reports in reptilians and crocodiles and fish. and in insects and in mollusks, in octopods, for example.
If we look more closely and if we just open our minds and are willing to see this kind of behavior, we might see it in even more species that we are not really expecting them to do it. The question is indeed, what is it good for? Because it comes with quite some costs. I mean, you're distracted, so you're more susceptible to be picked up by a predator, for example. You can injure yourself. So you burn energy, so it must have some adaptive value to the animals.
And our hypothesis is that this particular kind of behavior, this voluntary passive movement, helps the animals to shape their body self perception. Exactly what I said initially, that they have a better understanding of their own dimensions. And this, of course, is especially for... for us, for example, important when our body still changes during the juvenile period. When we're still children, we play a lot.
because we are still growing. And when we are adults, not so much anymore. So it sounds like play is a form of experimentation where we see how well we can adapt to the world. Exactly. Dr. Huthrath, thank you so much for your time. Well, thank you for having me. Dr. Wulf Heterhut is an associate professor at Northumbria University in the UK. In the fall of 2001, while Americans were still grappling with the horror of September 11th,
But what's strange is if you ask people now what happened with that story, almost no one knows. It's like the whole thing just disappeared. Do you know? From Wolf Entertainment, USG Audio, and CBC Podcasts, this is Aftermath, the hunt for the anthrax killer. Available now. I'm Bob McDonald and you're listening to Quirks and Quirks on CBC Radio 1 and streaming live on the CBC News app. Just go to the local tab and press play wherever you are.
The troublesome task of understanding how dinosaurs behave when we have little more than their bones to work from. These things have been existed for tens of millions of years. When you're trying to build a chain of logic or a chain of evidence with A following from B and C following from B, if A is not actually certain or it's not as correct as you think it is, then obviously you're...
potentially building a bit of a house of cards. When you think about the research tools used by scientists, you probably imagine test tubes, sterile beakers, and gleaming high-tech machinery, like centrifuges and microscopes. you might not imagine penguin poop. But the feces of the famous flightless seabird turned out to be an essential component for the work of a team of biologists in Australia who were studying one of the ocean's most important life forms, krill.
These shrimp-like crustaceans are small, about six centimeters long, weighing perhaps a gram, but they serve a mighty purpose. They are a vital food source for a range of animals like seals, birds, fish, and squid. Blue whales can eat 40 million krill a day. And to understand the way these animals respond to predators in the lab, penguin poop turned out to be as valuable as gold.
Dr. Nicole Hellesey led the study. She's an adjunct researcher at the Institute of Marine and Antarctic Studies in the University of Tasmania in Australia. Hello, Dr. Hellesey. Welcome to our program. Hello, Bob. It's nice to meet you. What inspired you to use penguin poop to help you study krill behavior in the laboratory?
Well, we'd seen that they'd reacted to food in their swimming behavior, and we thought, well, surely they'd have to react to their predators as well. Well, why is it important to figure out how krill behave when the smell of a predator is around?
So it helps us understand how they respond to their predators, not just penguins but all their predators as well. But it also gives us more information about how they change and adapt in their environment and where we need to conserve if they're not going near penguin colonies. It might be important to conserve the area around that penguin colony for the penguins, but it's not going to be as important for the krill. Well, why are krills so important for the environment?
So they're the main link between all of that. Small stuff in the ocean, all the algae, all of those little tiny crustaceans and other things that are out there. And then all of our beautiful big creatures like whales and penguins and seals. So they're that main link in Antarctica.
So if we don't look after them, we don't get to have all of those big, beautiful creatures that we think of when we think of Antarctica. Well, take me through your experiment. How did you study how krill behave when penguin poop is around? So we had a horizontal flume. That just means that we had a big tube of water where the flow went from left to right. That's all that means. And we then were able to control how fast that water was moving with a valve.
And then we could add different chemicals in. So we had chlorophyll, which was a proxy for their food in the algae. And then we had the penguin poop, which is obviously being used as a proxy for having a predator nearby. And we could look at how their responses changed in all these different conditions. I'm just curious, what does penguin poop smell like?
It's a little bit like fermented shellfish. It's not a great smell. You do get used to it after a while, but it's not pleasant. Oh, so your lab had a certain je ne sais quoi odor about it? Yeah, we were very lucky. We had a couple of people who were down there that we call birders. So they do all the studies with seabirds and penguins down there. And they were able to collect the penguin poop forest under their permit. So what did you see when you added the penguin poo to the krill?
So particularly in the bigger flows of water that we had when we put the penguin guano in, we could see the curls start to immediately drift back with that current like, nope, I'm just going to let the current push me away from where this predator is coming from. But when they then realised that they couldn't escape from it because obviously they're inside of a tank.
They started to go to the edges of the tank. They started to zigzag away. They started to clump together more. So it became very obvious that they were trying to avoid. There's a predator chemical trying to get away from it. Get me away from that bad smell. Yeah, absolutely. I mean, obviously the Adelie penguin poop we were using was mostly crushed up krill as well. So I can't imagine that it'd be nice to smell dead anything, but particularly your dead friends.
Now, you mentioned that you could also add food, chlorophyll for the krill. What difference did it make if there was food available? So they would still avoid where the chemical was coming from. But once they realized that they were safe after a few minutes, they'd actually start feeding on the chlorophyll in the water, but just at a much reduced rate to what we saw when there was no guano around.
Well, how big a role does the krill's sense of smell or taste play in how they navigate in different threats in the ocean? Well, that's part of what we're trying to understand is we don't actually have a lot of information of how they perceive their environment and how they respond.
to these changes whether they be chemical inputs or vibrations in the water or anything else so this is part of us helping understand how krill respond to these kinds of things in their environment Well, how well equipped are krill to detect things in the ocean water?
So they have these beautiful big compound eyes, like most sort of crustaceans do, but they've also got a large set of antenna at the front of their body. So they've got two really long ones and they've got four little short ones that are on the end of their snoot. I'm not sure if snoot's the technical term for the end of their face, but that's what I'm going to call it. But all of these antennas can detect chemicals. They can...
pick up vibrations in the water, different currents. So they've got lots of different ways of getting inputs from the environment around them. That's pretty amazing considering how small they are because lobsters, I think, only have two antennas, is that right? Yeah. Yeah. So Krilla actually, they evolved a long time ago. So they've actually got some like remnants of stuff that other things have, you know, lost over time.
So what's the big picture here for the role that poop plays in the behavior of marine organisms? So poop might play a role of having animals avoid where their predators are. It might change where they're going. It might start them... fooling and swarming faster. But it might also then be a case of they go, hey, there's a predator in that direction. I'm not going to go that way next time. I'm going to go somewhere else. Have you been out in the ocean and seen large schools of krill?
I have. I've managed to capture a few large swarms of krill in my net to then be able to take them to the aquarium to do experiments on them. But what's it like to see them in the wild? I mean, it was fantastic for me the first time I actually saw them in the wild. I'd been studying them for about 12 years, so it was kind of a... a long time coming by the time I actually saw them. So it was a very happy day. How large is the swarm?
The one that we collected most of our pearl from was about 500 meters long, 100 meters wide, maybe 50 meters deep. So it's a decent size swarm. Wow. Tiny crustaceans, but they play a big role in the ocean. They sure do. They have huge impacts. eating all the algae and all these big phytoplankton blooms that they have every spring when the sea ice melts, but they then poop all that carbon into the deep ocean and get eaten by whales. They're kind of fascinating when you start to look into them.
Amazing life under the sea. Dr. Hallisey, thank you so much for your time. Thank you so much, Bob. Dr. Nicole Hellesey is an adjunct researcher at the Institute of Marine and Antarctic Studies at the University of Tasmania in Australia. If you're a regular listener, you know we love our dinosaur stories, especially when they can shed light on the lives of these prehistoric beasts.
It would be this extremely large animal doing this probably extremely elaborate showy display to show its more tender side to the female. So maybe they use these low frequency sort of rumbling noises to communicate over... So they might have been used to attract mate. They might have been used to distinguish between the different species living at the time. And those horns might have even been used to ward off predators. They hung out together as a group.
it's very likely that they did so not just because they liked each other's company, but there was some sort of a survival mechanism to do so. Now, you might be asking yourselves, how do they know these things? We're talking about dinosaurs that lived from about 245 to 65 million years ago. So it's not like we can observe them and get direct evidence of how they behave.
But in a new book, Dr. Dave Hohn explores how science has advanced to better tackle this question and the many pitfalls that can lead paleontologists astray. Dr. Hohn is a paleontologist and a reader in zoology at Queen Mary University of London. His book is called Uncovering Dinosaur Behavior, What They Did and How We Know. Hello, Dr. Hohn. Welcome back to Quirks and Quarks. Thank you very much for having me on. It's genuinely a privilege and a pleasure.
What was it about the field of paleontology that inspired you to write a book about dinosaur behavior? So I think there's a lot of, or certainly there was a lot of perceived wisdom about how ecology and behavior worked when the way it was implied to dinosaurs, which was often quite dated or problematic. And there was a very understandable but real temptation to kind of...
leap on an example or a single data point or kind of the most obvious explanation as being definitively correct or true, which I think a lot of the time it may not be. And then, of course... Because of, as you say, the problems of dinosaurs, you know, these things have been extinct for tens of millions of years. When you're trying to build a chain of logic or a chain of evidence with A following from B and C following from B.
If A is not actually certain or it's not as correct as you think it is, then obviously you're potentially building a bit of a house of cards. Well, how much can we learn about dinosaur behavior when all we have are their fossilized bones? So we can do an awful lot. And so I don't want to give people the impression that I think everything's a mess and everything's a disaster and we don't really know anything.
But I think we're in an odd position where we can do a lot more and we can do a lot better than perhaps we have done. But there's things we've always relied on, but we can, I think, just refine them. So, for example, there's some pretty basic stuff, like if you want to know if something's a carnivore or a herbivore, the shape and structure of its teeth.
carnivorous animals tend to have sharp cutting curved teeth and herbivores tend to have kind of grinding or very good slicing teeth for tough vegetation and things like this. You can combine that with other data from things like the way the jaw muscles are structured. You can get isotopic data from the bones, from the preservation, which will actually tell you something about their diet. We maybe find things like bones preserved in the stomach.
or seeds and leaves and things like that preserved in the stomach. So you can build up quite a lot of data like that, and you can drive those sorts of analytics into some really quite complicated stuff. So it's not just basically, you know, are you a herbivore a carnivore? We can do much more than that.
But at the same time, as you say, the data is often quite limited. And when you're getting into more plastic behavior... like social behavior you know animals living on their own or in groups or switching between the two or only doing it in the breeding season or it depends what environment they live in or how many predators are around
Obviously, it gets a lot, lot more complicated, and that's where I think we need to be much more careful about the conclusions we're coming to from the data we have available. Well, on the flip side, how can studying just their bones give us any false impressions of their behavior? Well, so a fairly clear one is just that social behaviour. So animals will congregate for all kinds of different reasons.
We've got to remember that when you find a fossil, even if it's a complete articulated skeleton, or as we see, you know, sometimes dozens, hundreds, thousands of complete articulated skeletons of dinosaurs. That's where they ended up being buried. That's not even necessarily where they died, let alone how they normally live.
So an example I like giving is you may have seen or your listeners may have seen this does the round semi regularly online. There's this wonderful photo or fascinating photo of. Literally hundreds of elephants moving together. It's a black and white photo from the 60s, I think, of Kenya.
And this seems to go around the Internet about every six months. And it's always set up with the, isn't it a shame we don't have this anymore? Look what humans have done to elephants, et cetera, et cetera. And I'm not suggesting that elephant populations have not been decimated by human activity.
But the reason that photo is taken is because there was a massive drought on. And that is every elephant from tens, perhaps hundreds of kilometers, all heading in the same direction because they are desperately short of water. That's not elephants normally lived in herds of hundreds and hundreds of animals.
But of course, if they're all moving that way and they're all going to end up in the same place and if there's no water there, what are you going to end up with? Well, potentially, you're going to end up with a couple of hundred or a couple of thousand elephants dying in one place. And then they might be fossilized. And then we might dig them up and go, wow, elephants lived in herds of thousands.
And because babies actually tend to die in these events, young animals are much more vulnerable when it comes to environmental stressors. We just find the animal. And it's, wow, elephants lived in herds of a few hundred or a few thousand, and it was just the adults. The babies had to fend for themselves, or maybe they lived somewhere else or in a different ecosystem, or maybe there was very low reproduction.
No, they're just already dead. And this is the result of a drought. And of course, the reality is elephants usually live in groups of, you know, 10, 20. There are some big herds recorded of 50 and 100, but they're usually about half young animals and half adults. So that potential fossil can give us an incredibly false impression of what the actual behavior was like. Now, one of the things that you really drive home in your book is the importance of context. Tell me a bit about that.
Well, that's exactly the sort of thing. It's very easy to dig up. as we have done for dinosaurs. You have an amazing one in Canada, Dinosaur Provincial Park in Alberta. There's a bone bed of an animal called Centrosaurus. So this was a kind of rhino-sized animal. It's a close relative of Triceratops, so the famous animal with the big frill and the three horns. Centrosaurus just has one big horn on its nose.
But there are hundreds, maybe thousands of individual centrosaurus in several different layers over in Dinosaur Provincial Park. And yeah, you can take that and go, OK, they're living in herds of thousands. But if you look at the context, and I mean by that in this context, getting into the toponomy, so the study of the fossilization process and what happened to these animals.
we have the potential to piece together a much bigger picture of what's going on. Things like droughts leave a trace in the rocks that the animals are buried in. When we have multiple layers like this, we can see, is there something in common with it?
So for example, if it is a big drought, we'd expect that to similarly drive... adults together and maybe kill off the babies early we might expect that to always be at the same time of year you know we don't usually get droughts in winter you do usually get them at the height of summer
So is there something from the way the rocks have formed in terms of was it dry or wet at the time? Maybe there's stuff in the pollen grains. We can often pick up stuff again from isotopic signatures. If we find that every single time we find a mass bed of Centrosaurus... that it looks like it was the height of summer and potentially very dry, well, then we've got quite a good reason to think that maybe this is drought-driven and not natural.
If, on the other hand, there are all different times of the year and all different seasons in all different places, Well, that's probably not environmentally driven. And then we can be a lot more confident and go, OK, they probably lived in groups the whole year. And we keep catching these mass mortalities from single disasters at various different times.
You also make the point in the book that where we find the fossils is not necessarily where the dinosaurs lived, because that's where they died. but their bones could have been scattered by rivers or predators or whatever. The context, again, like where you find them is important. Yeah. Again, you've got a wonderful example with Boreal Pelter.
So again, dinosaur provincial, well, not dinosaur provincial park, but it's held at the Royal Tyrrell Museum in Drumheller. And this is an absolute fantastic nodosaur. This is one of the armored dinosaurs, very slow slung animal, lots of... armor and spikes across it. And that was found what was I think the estimate was something like about 200 kilometers out to sea. Now, not now, but the Paleo Ocean. We have an idea of where the coastline was back then.
It's from a fossil locality that's full of marine reptiles and fish and sharks and things like this. And one big dinosaur. Were they swimming 100 miles out to sea? No, this is an animal that clearly got washed out. But maybe it was living up estuaries. Maybe it was living on the coastline. You know, you do need to be careful about that. In the case of the arm of dinosaurs, actually, we do tend to often find them in the sea.
That suggests that maybe they are actually hanging around coasts or estuaries. They're being washed out. But of course, if they're in large numbers, that's much more likely to happen to them and far less likely to happen to... Triceratops or Tyrannosaurus or one of the other dinosaurs that's perhaps more in land. You also talk about biases that can arise from the fossilization process itself, like what gets preserved and what doesn't. Can you give me an example of how that can skew a conclusion?
So crocodiles, even when they're a meter or so long, which is a pretty big animal, like, you know, a meter long crocodile will definitely remove fingers. It might remove hands if you get on the wrong side. about half their diet is invertebrates. So they're eating spiders and snails and insect larvae in the water. They're also eating fish and frogs and things like this, but like half their diet are insects.
But obviously the fossilization process does not generally favor softer, squidgier tissues. It favors bone and teeth and really hard things like snail shells or ammonites and stuff like that. So actually, again, if you imagine what a fossil record of crocodiles might look like, we'd find loads of them with fish bones in the stomach or frog bones in the stomach. OK, they're eating fish and frog. we're missing a full half of their diet because it's very, very unlikely to preserve.
And then if you transfer that over to something like Microreptor, as I say, it's about this crow-sized gliding dinosaur from the forests of China from the early Cretaceous, so 110-ish million years ago, I think the numbers are. We've actually got four different micro-raptors preserved with stomach contents. One has a lizard in it. One has some fish in it. One that I described with some colleagues has a mammal foot in it. And one has a bird in it.
Now, if you found any of those on their own, and of course, this is what happened when the fish one was discovered. It's like, wow, microepter ate fish. Then the bird one, oh, and it also ate birds. And of course, now it looks like it probably ate everything. But again, that's still just the bones. I would bet it's probably eating an awful lot of...
insects and slugs and snails and, you know, caterpillars and things like this, which again, are just simply not going to show up. But again, if we'd only found one of those specimens... we'd have an immediate tendency to focus on it as a specialist in X, Y, or Z. But even when we have a plethora of them with the different data, we're probably still missing a bunch of other things. How important is the study of living animals now to help fill in the picture of how dinosaurs might have behaved?
I mean, it's really, really important. It's a little bit trite to say, of course, dinosaurs were living animals and we need to think of them as such. But I think it is something that we do tend to overlook. but they do produce a fantastic framework for us. There is lots of, in particular, anatomy that comes around again and again and again because it's a very good way of doing things. So fish-eating dolphins have a very similar jaw shape and tooth shape.
to fish eating crocodiles and to some fish eating fish and then we see it in the what we think of as fish eating ichthyosaurs in the fossil record and then again even some dinosaurs so you can use things like that as a very clear signal for what animals are doing But even when it comes around to stuff like behavior and... social behavior. And we heard a little clip of that in the introduction, someone else speaking about, you know, why do animals form groups?
Well, a really, really common one is defense from predators. That is a massive, massive driver for an enormous number of vertebrate species, relatively large animals usually living on land, but also in sea. It's very common for fish, for example.
And actually, we see for various species, the number or density of predators drives the group size. In other words, when there are more predators around, you either start forming groups or you get a bigger group because you have better defense against them. So having that context and framework to understand why this group might form and is that group something that's genuine, as we talked about earlier, is, yeah, how we need to try and understand these animals.
Well, let's talk about, I think, everyone's favorite dinosaur, the T-Rex. They're always depicted as a fierce predator, usually ripping apart another dinosaur in a fierce battle. What do we know about what a day in the life of a T-Rex would really be like? So this is just the sort of thing which I think is really, really very difficult because it comes down to the challenge of actually testing some of these ideas. What we obviously want to do as scientists ultimately is...
test hypotheses and see does the evidence actually favor or push us away from an individual idea or individual set of ideas that we've been building up. But it's really very, very hard to know. You know, we do know that large modern predators, you know, they're not feeding most of the time. Lions aren't eating or even hunting. 20 hours a day, it's the opposite. They're usually sleeping 20 hours a day.
But that's going to vary massively depending on are you in a hotter or colder environment? Is there lots of cover or not? What's the prey density like? Is that prey density with lots of the right kind of size animals that you'd really prefer to go after or fewer smaller ones? In the case of things like lions, are you on your own or in a group or how big your group is?
Or what are the demands from the fact that you've got pregnant or lactating females that might need more food? You know, all of these are going to affect the day-to-day lives of things like lions, which are very well studied indeed. There's so much variation we'd struggle to say what a truly typical day is like. What do you see as some of the more exciting scientific advances that could further help clarify issues about dinosaur behavior?
I'm not sure. I mean, of course, we're always finding more specimens. We've always getting more researchers into the field. We're always getting into new techniques in terms of, you know, what can we do to scan a fossil or extract?
information from it or do new digital reconstructions and all of these things. But actually, I think a large part of it is we need to better apply the knowledge and understanding that we already have now and kind of you know, make a better fist of analyzing the data we have.
So a really good example of this is Ancyornis, another little feathered dinosaur from China. A few years ago, a team put together a study looking at the color. So this is a big new thing, is the color of dinosaurs. And we're starting to get some real hints. And they found that Anki Ornis is probably grey and black with some white highlights and maybe a bit of red on the head. But that one individual...
What about male versus female? What about adults versus juveniles? Maybe the animals in the north were a different colour to the ones in the south. Maybe it's a breeding plumage and they only had those colours for a few weeks of the year. We actually have dozens, if not hundreds, of specimens of Anchionis preserved well in us with the feathers that we can probably do this color test of.
But of course, now we've done it once everyone thinks we know the answer and we've moved on to something more exciting. The data is there. The techniques are there. We just haven't applied it. And yet that will really tell you something about... how these animals may have interacted or signaled or what the variation was like, how they changed over time. Did they have white camouflage in winter? If they did, that probably tells you they're very vulnerable to predation because you need to hide.
If you're not very vulnerable to predation, you can have lots of bright colors all year round. So it really tells you a lot about their biology. We can do it. We're just not doing it or at least not doing it yet. really bringing dinosaurs to life. Dr. Holm, thank you so much for your time. Thank you very much for having me. Dr. Dave Hohn is a paleontologist and a reader in zoology at Queen Mary University of London. His book is called Uncovering Dinosaur Behavior, What They Did and How We Know.
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