Story of Birds (featuring Dr. Steve Brusatte)

This is an iHeart podcast. Guaranteed human. Surprise! We're here! Dad, what is that? It's a... hungry horse! Dad, wrong hungry horse. This is a horse in a field. I meant the family pub, with daily deals like buy one burger, get one for a pound on Fridays, candy, mania and free life sport. Oh, yeah, that does make more sense. Say yes to unbelievable value for the whole family. Hungry horse. Say yes. Search online and book your table. Visit hungryhorse.co.uk for full season seas. The people of Britain love their fancy blenders. They've bought loads of them. And luckily, if they bought them with Barclay Card, they earned rewards. In fact, they'll earn rewards on all their eligible purchases. It's a more convenient way to consume your broken bench! What you buy is your business. Giving you rewards on purchases is ours. Barclay Card. Back in your future. 28.9% APR representative variable, subject to application, financial circumstances and borrowing history, T's and C's apply. Imagine this. You're walking through the woods by yourself. You've been told there are dinosaurs afoot. You hear a rustling in the brush behind you, and the hair is on the back of your neck, stand on end. Ha! What made that noise? You start to break a sweat. You hear the noise again, and then out of the woods comes... A chicken? Ha ha ha ha! Well, technically, a chicken is a dinosaur. And if you don't believe me, we have Dr. Steve Roussati, author of the new book, The Story of Birds, on the show today to try to convince you. And while I have to admit that chickens don't really inspire the same level of awe in me as Ankylosaurus or T-Rex, neither of those species survived the catastrophic collision of an asteroid with Earth during the Cretaceous period. But somehow birds did make it through. So maybe birds are more interesting than I've given them credit for. And maybe those birders really are onto something. Let's see. Welcome to Daniel and Kelly's Avian Universe. MUSIC Hi, I'm Daniel. I'm a particle physicist. And if I discover a new particle, it's not getting a Latin name. Hello, I'm Kelly Wienersmith. I study parasites and space, and I am part of the team that has described two species, and we gave both of them fun Latin names. Because they need them. They have to have names, man. Get over it. Because biologists, when they talk about something, they have to start with the Latin name and then never use it again. They just dump it on your brain to tire you out before you even hear the interesting bits. Okay, all right. So apparently this is what we're going to be talking about. So here's the thing. Look, not all species have common names. Some of them just have Latin names. And so what are you supposed to do? Do you want me to just be like, bug one? Like, that is their name. Yes, bug one is much better than going like, this thing, Gobbata gubata, which I'm never going to use again, and you had to hear anyway, and we'll just talk about is bug one. I just find it confusing and not very helpful. But anyway, my question to you today, Kelly, is, what is your favorite bird? What is my favorite bird? Yes. Oh, what is my favorite bird? Uh, gosh, I don't know. I like a lot of birds. My favorite bird. And this is maybe going to be a surprising answer. Is a bird that makes me happy when I am sad. And it is the turkey. And I was, I was once lost in the woods, and I was supposed to be doing this like survey, and I was up on a military base, and it was when the rattlesnakes, it was a rattlesnake survey, and the rattlesnakes were breeding, and I was all by myself, and I wasn't supposed to be by myself. It's a really long story, but I was like kind of freaking out. This was really early in my career. And I came across a bunch of turkeys, and they started doing their weird gobbling, and the way they walk, where they kind of like move their heads back and forth, they just looked so ridiculous that I literally, I just sat down and I watched them, and I was able to regain my composure, because I was like, you guys are ridiculous, and I'm going to be okay. And now that I live in the woods in Virginia, when it's in the spring, I get up in the morning before everybody else, and I sit on the porch, and I open my Merlin app, which identifies bird sounds, and I drink my coffee, and there's all these cute little birds making all of their calls in the morning, and so it tells me, oh, there's an indigo bunting, and there's the cardinal, and stuff like that. There's a tufted tit mouse, and then out of nowhere, you'll hear, boogaloo, boogaloo, boogaloo, boogaloo, and I will just crack up, you know? And so like, it's interspersed with all of this beauty. There's just this ridiculousness that always makes me smile, and so maybe my favorite bird is the turkey, and every year we name a turkey. It's the biggest male on the property, and so yeah, I guess maybe it's the turkey. They're not the most beautiful. They look ridiculous when they try to take flight, and maybe I, I don't know, I see myself in them. I don't know. And the turkey is the kind of thing that makes it hard to understand that birds are related to dinosaurs, you know? Yes. You just don't have that gravitas, the awe of danger, you know? No, no. That you expect from a dinosaur. But what about you? What's your favorite bird? I love the crow. It's jet black. It's totally obviously evil. It's crazy smart. There's something just really impressive and terrifying about crows. Crows I can see is like having a long lineage of killers. What, but they're not like dangerous or anything. They're just like, they're brilliant and beautiful and amazing, and they're not like out there stabbing people with their beaks. What are you talking about? I mean, crows remember people who have been mean to them, and they can like take revenge. So yeah, be careful around crows. I think you're paranoid. They're not like, like, like messing with your break pads or something, man. They're just like, they're just out there eating stuff. No, I think there's some crow equivalent of rape my professor, where they're like, this guy's a jerk and everybody should attack him, or like poke his eyes out or something. I'm always nice to crows. They're like the mafia, you know? You don't want to anger them. Okay, all right. Well, the reason we're talking about our favorite birds today is because my friend Steve Brusati has a amazing new book out today called The Story of Birds. A great book. And we got him on the show today to tell us all about birds, bird evolution, and we had so much fun in this conversation today. Even though we heard a few Latin names. Oh my gosh, get over it. All right, let's bring Steve on the show. I never will. Dr. Steve Brusati is a paleontologist and evolutionary biologist at the University of Edinburgh. He's described over 20 new species of fossil animals. He writes bestselling popular science books. And he's the paleontology consultant for the Jurassic World series. And when I told my daughter that, she thought that I was cool for the first time because I had just met Steve in person. His new book, The Story of Birds, a new history of their dinosaur origin to the present, comes out today. Steve, you are from the United States and you've moved to Edinburgh. How is the haggis? I like haggis. I had never tried haggis until I moved to Scotland. I'm from Illinois originally. I've been in Scotland for over 13 years now teaching the Earth Sciences degree here at the University of Edinburgh. And I found that I quite like haggis. But even better than haggis, I must say, is vegetarian haggis, the one that's made with lentils and beans and all kinds of spices. It's really, really, really, really, really good with the added benefit that you're not eating lungs. So there you go. I had the vegetarian haggis. I loved it. But I'm confused. What's haggis-y about vegetarian haggis? I thought it was all the organ meat that made it haggis. Yeah, it's a fair point. And I think so they try to get the spice mix. Correct? I don't, the spices, I don't know. I'm not a Scottish chef, but I think it's a lot of pepper and mace and these kinds of spices. And they must put something in there to give you that tinny-ness of organ meat. I don't know how they do it. It's alchemy. But if you're interested in Scottish cuisine and you want to try haggis, but you want some training wheels first, try the veggie haggis. All right. Also, welcome to the show. Yes. Oh, yeah. Let's talk about birds. Haggis, what are we doing here? Yeah. No, wait, I have one more ridiculous Scotland-related question before we get started. Can you evaluate Kelly's pronunciation of the town in which you live? It's pretty good. It's pretty good. I didn't know how to pronounce it when I was actually quite embarrassingly when I first came to the UK. I did a master's degree in Bristol down in England for a couple of years, which was great. I learned a lot about paleontology there. A lot of what I study now is based on that foundation. I met my wife in Bristol. Wonderful. But I also learned a lot about the English language, the Queen's English. And it took me a while. And I didn't know how to pronounce Edinburgh then. I think I do now. But undoubtedly, if real native Scottish folks are listening, they'll probably critique my Chicago accent way of saying Edinburgh. We've both appalled them, I'm sure. We're doing the best we can as people born in America. Let's jump right into what would have surprised 12-year-old Kelly, which is that birds are dinosaurs. Like parakeets and chickens are actually dinosaurs. And I think childhood Kelly would have been kind of appalled by this. How did we figure this out? It is absolutely true. That's the first thing to say. This is true. It's not a rumor. It's not a conspiracy theory. And it's not something like scientists are trying to spin words or to get too cute or change the definition of a word you thought you do. It's true in an evolutionary sense. Birds are dinosaurs. Birds evolved from other dinosaurs. They are part of the dinosaur family tree. They have all of the classic features of dinosaurs, the things that make dinosaurs dinosaurs, which are things like a big open joint in the pelvis where the thigh bone fits in, extra bones in the backbone that connect the hips to the body, those kind of things. So the way to think about birds and dinosaurs is how we think about bats. And you say, what is a bat? Well, a bat is a mammal. Of course, it's a mammal, right? It evolved from other mammals. It's part of the mammal family tree. It has all the classic mammal features. It has a hair and molar teeth and feeds its babies milk. Of course, it's a mammal. It's just a weird type of mammal that got small, evolved wings, and developed the ability to fly. And birds are the dinosaur version of that. They are one peculiar group of dinosaurs that got small, evolved wings, and developed the ability to fly. And it's not like birds evolved from T-Rex or Brontosaurus any more than a bat or a human evolved from an elephant or a whale. It's just that birds are part of that broader dinosaur family the same way bats or humans are part of the broader mammal family. That was really fascinating. But to digest that, I think I need to understand a little bit better what exactly makes something a dinosaur. Is it the evolutionary tree? You're saying this whole branch and everything descended from it is a dinosaur or is it morphological? Like if it has these things as part of its body, then it's a dinosaur or is it both? It is both. It is both. And it's the same for if we ask what makes a mammal a mammal. Mammals are a group on the family tree of life. And that group is defined by the features they have or the features that their common ancestor evolved. Because a mammal can lose some of those features that makes mammals mammals. There are naked mole rats that don't have hair. It doesn't mean they're not mammals, but they evolved from the ancestors that did have hair. So when it comes to dinosaurs, dinosaurs, that's a group on the family tree of life. It's the group basically of iguanodon and megalosaurus. Those are two dinosaurs. The first two ones that were named and described by scientists back in the 1820s. They're the anchor points for what makes dinosaurs dinosaurs. And that broader group defined by those anchor points has a set of unique features that are not seen in other animals. Things like that big open joint in the pelvis, which really is all about walking more upright. Dinosaurs walked more upright with their legs under their bodies compared to other reptiles that slither around or that sprawl around like crocodiles and lizards. And extra backbones linking the hips to the body column. Those are the things that make dinosaurs dinosaurs. They might seem like subtle anatomical features. And in a way they are, but they are quite distinctive things. Very weird for a reptile. Dinosaurs are a type of reptile and they are unusual reptiles. And birds stem from that dinosaur group. So it's simply a fact of genealogy. It's the same way that I'm a brusadi because I was born to parents who were brusadis part of the family. I have the classic, you know, features, physical features of my family due to the genetics of the family. And it doesn't matter if I move away to another country like Scotland. My family's back in America. I'm still a brusadi even though I'd change. And that's the same way we need to think about birds. Yes, I know it seems like a bird looks nothing like a T-Rex or a Brontosaurus. But it's not that it evolved directly from those dinosaurs is that it's part of the broader group. And birds have become very specialized in their own right. They have changed, but they are still dinosaurs. Once you're in the family, you cannot leave. It's like the mafia. And that's how we need to think about birds and dinosaurs. There you go. So there's lots of times in science when humans draw really clear distinctions. And then when you look more carefully, you're like, this is kind of an arbitrary dotted line around something that's important to us. You know, in physics, for example, planets are like a kind of made up category. But emotionally, they're important to us. Is dinosaurs like that or is it really well motivated and clearly distinct? It's I mean, it's both in a sense because of course there are historical conventions. What we consider a planet, there's a definition that is developed over time. That astronomers have had to agree on as humans, classifying things. And the same thing with species on the tree of life. So there of course is an arbitrariness about what names we put on things. But the key thing is for planets, I suppose that, you know, they are what they are. They're a certain size. They're made up of something. They're rotating around a star. I mean, those realities exist regardless of what you call them. And with the family tree of life, you can put whatever names you want on anything. But the reality is that life has evolved. It's changed over time. There have been ancestors that have given rise to descendants and those descendants have given rise to new things. And whatever names you want to call any of this stuff, the reality is that the birds we see around us today, the ones I'm literally looking at outside my window now, there's some pigeons and some magpies here outside my window. They evolved from dinosaurs. They're wings, they're feathers, they're wishbones. All of those features that make them birds are things that dinosaurs first evolved and birds inherited from them. So that process of evolution, that historical story, that is what happened. That is the key. Call these things whatever you want. But the reality is that today's birds evolved from the dinosaurs of yesteryear. And that makes them a part of the same family line. So if I'm thinking about the mammal family tree, some of our closest relatives that people can picture in their minds would be like the chimpanzees and the bonobos. If we're thinking about dinosaurs that people could picture in their mind, that would be some of the closest relatives of birds. So that's not going to be, you said it's not T-Rex, it's not Brecciosaurus. Is it like a raptor? Because a velociraptor has the word raptor in it. Maybe it's that. What dinosaur that people could picture would be a relative of birds? That would be pretty close. And can we call it the Velocichicken? Yeah, you got it, the Velocichicken. It is those dinosaurs, the raptor dinosaurs, what technically we would call the dromeosaurs and the truodontodinosaurus. But what we normally just call the raptors when we're chatting, the ones that are famous from Jurassic Park and Jurassic World, Velociraptor itself being the real iconic one, they are the very closest relatives and basically the ancestors of birds. And this is one of the things we have to wrap our heads around. When we hear the word dinosaur, the image that comes to mind for most of us and for me as well, somebody who studies these animals, the image that comes to mind is a giant reptilian behedon. Whether it's one of the long neck dinosaurs, whether it's a T-Rex the size of a boss, or one of those big stegosaurs with the plates on his backs or the triceratops with horns, these sublime, almost monstrous giant creatures. But not all dinosaurs were like that. And it's just like with mammals today. Yes, we celebrate the elephants and the rhinos and the lions and other big cats and the gorillas and so on. But the vast majority of mammals are actually quite small and it's true with dinosaurs. There was a huge range of dinosaurs, some were quite small. The raptor dinosaurs were some of the smaller ones. And it's from those raptors that birds arose. One of the things in your book that I found awesome slash unsettling was the description of the experiments where you've got chick embryos and they've been genetically modified so that you can see the dinosaur stages. Can you tell us about those experiments? It is morbid stuff, frankly. I'm a paleontologist. I like digging around in the dirt and the sand and the rocks looking for fossils. I'm not somebody personally who does these genetic experiments, but I have many colleagues that study what's called evodivo. So blending together the study of evolution over time with the development of modern day organisms from embryo to adult. Because generally as an embryo develops into an adult, they replay the tape of evolution. Not perfectly, of course. But when we are a little baby in the womb, there is a period of time, a short period of time, where we have gills, we have tails, we lose those things, but we have those because our ancestors had those things. We have the genes for those things still inside our genome. So in that very coarse way, you're seeing the development of a human replay in part the evolution of humans from other animals. It's true with birds as well. If you look at how a little baby chicken or a little baby quail develops in an egg and goes from the tiny little speck of an embryo into a hatchling, you actually see this little bird go through dinosaur phases. And you can see it most clearly with the pelvis. The pelvis of a really young quail, for instance, it really looks like the big, bulky, muscular hip of a T-rex. If you were just to show me an image of those bones as they're developing and tell me nothing about the size of those bones or anything about the scale of them, I would say, oh, that really looks like a T-rex pelvis. Well, it's not. It's the tiny little developing pelvis of a baby bird. And then over the next few days, the bones morph and they shift and they change shape and they sweep backwards into the more gentle, delicate backswept pelvis of a bird. But you see this day by day, and it's like you're marching up the family tree of dinosaurs. It's incredible. Now, maybe that's a bit abstract, though. I think what's even more slam-dunk for most people, if I talk about how birds develop, is the fact that birds today don't have teeth. No birds have teeth. Birds have beaks. This is central to being a bird is one of those most birdie features of being a bird. And the ancestors of birds, of course, did have teeth. Raptor dinosaurs are some of the nastiest, fliestiest, sharpest teeth around. So what we would predict, of course, is that during the course of the origin and evolution of birds, birds lost teeth. Well, do we have evidence for that? We do. In the fossil record, we see primitive birds with teeth. Wow. Fair enough. That's pretty cool. But these are long dead fossils. What's even cooler, I think, and which really drives home the point, and which really, I think more than anything, just proves in the most visceral way that birds are dinosaurs, is that you can tweak the genes of a growing chicken and make it grow little teeth in the egg. And those little teeth, they look just like the teeth of a raptor dinosaur. It's crazy. It is freakish, honestly, when you look at it. You sense this Frankenstein monster thing. And it is quite monstrous, actually, because once that mutation is activated, those little chicks cannot survive to hatchling. There's something that is just completely fatal about that mutation. And maybe the geneticists know, I don't know, I'm not a geneticist. I've only learned about it from what I've read. But that's probably why no birds have teeth today. Those dinosaur genes for teeth are lurking in their genome, but they can't be activated because there's something fatal about it. But they are there, and you can see a chicken with little velociraptor teeth in the embryo. And that really should just go and prove it once and for all, if anybody has any doubts about the bird dinosaur lick. Wow, the toothy chicken. That's nightmare inducing. Totally. Okay, so I've been around the right kind of nerds throughout my life to know that pterodactyls are not dinosaurs. Very good. Yes. Yes. Yes. Yes. Yes. Wow, 100 points for Kelly. Look at that. Daniel, did you know this? I knew it only because I read Kelly's outline. But did pterodactyls and birds, like, did they share the skies at the same time? Like, were there pterodactyls, like, taking birds out of the sky and eating them? Or were there birds taking pterodactyls out of the sky and eating them? Like, what did the skies look like? And when are we going to get a pterodactyl versus toothy chicken movie, right? I want to see that one. That could be Jurassic World 17. Somehow, tell, I will tell the producers and the directors. We will get there eventually. I will do my best. It will be quite the movie. Maybe not, you know, I don't know. That's more of the maybe B-list type of film. But yeah, birds and pterodactyls. This is really fun to think about. So you're absolutely right, Kelly. Pterodactyls were pterosaurs. That's the more technical name, but it's the same thing. It means the same thing. They are not birds and they are not dinosaurs. They're often mistaken as dinosaurs. You often see them in the dinosaur toy sets and on the dinosaur posters. And they often show up in blockbuster dinosaur movies. Sometimes when the character is mistakenly even called them dinosaurs. Oh, so disappointing. The science consultants don't always get to copy edit the scripts. This is just a little insight. It's not your fault. I get it. I'm just throwing everybody else under the bus. But so if you hear Jonathan Bailey say that, he didn't mean it. He didn't mean it. He didn't know. But it is kind of one of those factoids that I think a lot of people don't know. Why would you know? It's one of those pub quiz, trivial pursuit factoids. It's my little boy's favorite factoid. He's six years old and he loves telling all of his friends and his teachers, pterodactyls aren't dinosaurs. They're dinosaur cousins. And I mean, they're sick. I think every under six child in Edinburgh knows this now. Just from here and from Anthony. But isn't it sort of in the category of things where scientists have a very specific definition and then the popular understanding is broader? Like I think most people think of dinosaurs as like big reptiles that lived hundreds of millions of years ago. In which case pterodactyls are in that category, even if they're not in the technical definition that you gave. Sort of the way that astronomers differentiate between meteors and asteroids. But like normal people, I don't care. I was streaking across the sky. That's what I mean. Yeah. Yeah. That is true. And there's other giant reptiles that lived during the age of dinosaurs, the Triassic, Jurassic and Cretaceous periods, that also were not dinosaurs. There were a whole bunch of different giant reptiles that lived in the water. Pleasiosaurus, Aethiosaurus, Mososaurus. I'm just ticking off the names because I know we want as many Latin names as possible. Our listeners' interest in them was. Wow. Wow. Thank you for that. But yeah. But the fact is that yeah, there were plenty of giant reptiles during the age of dinosaurs. Dinosaurs proper are only one group of those reptiles. And there is this more vernacular use of the word dinosaur, which is fine. I'm not going to scream at people the way that my son does. If they misuse the term, if they're acting in good faith. But the important thing for our story though is that pterodactyls are not birds. They are two very different groups. It's not that today's birds evolved from the pterodactyls or anything like that. Actually pterodactyls took to the skies first. And pterodactyls were the first group of animals with bones ever in the history of the earth to evolve powered flapping flight. And by that I mean wings that they could actively flap that could provide the lift and thrust needed to get airborne and move through the air. There's plenty of animals that can glide, that can soar, talking about flying squirrels and flying fish and these kind of things. But it's only pterodactyls and then birds and then bats, those three groups that have evolved powered flapping flight among animals with bones. The pterodactyls did it long before birds. Hold on, you said animals with bones so that you could exclude some specific group, like what, insects or who else? Yeah, so I can exclude all the millions of insects and just consider them inconsequential. Wow. It's a trick. It's a political trick I'm playing here. I'm glad you noticed that. Thank you. All of our beetle listeners are really offended. Yeah, there's plenty of other animals, lots of insects that have evolved powered flapping flight in their own ways. That's true. Let's take a break when we get back. Steve is going to tell us how the vertebrates, because who cares about the invertebrates, how the vertebrates, what about doing this? Invertebrates have Latin names too, okay. And we're back. Steve is telling us about how the pterosaurs were the first to be able to actually fly, and he's going to tell us how they did that. So the first pterodactyls took to the skies in the middle part of the Triassic period, back when all the land was gathered together as Pangaea, the supercontinent, the single giant slab of land. And this was the same time the first dinosaurs were evolving on that land. And so that meant that pterodactyls, they went airborne probably about 80 million years before the first birds did. Wow. So they were the pioneers, which also means they were there when the first birds evolved. The pterodactyls were the incumbents. And so really, when the first birds evolved, they were interlopers in a pterodactyl world. And they were insurgents. And it's not that they just took over the skies instantaneously. No, it actually took many, many millions of years for birds to gradually diversify and spread around the world and evolve into new species and start to push out the pterosaurs. And it was really a long evolutionary war of attrition. And by the end of the Cretaceous, a good, you know, almost 100 million years after the first birds evolved, there were still birds and pterosaurs living together. But things had changed. The very oldest true bird we have in the fossil record is archaeopteryx from Germany. This is this famous iconic fossil, half dinosaur, half bird. It has feathers and wings and a wishbone, just like a bird, but it has teeth in its jaws. It has big, sharp claws on its hands. It has a long tail, just like a raptor dinosaur. This is the most beautiful, perfect, transitional fossil you can imagine. Evolution captured in action like a freeze frame. And when archaeopteryx and its close relatives, the first true birds took to the skies about 150 million years ago, they had to welcome themselves into this world of pterosaurs. And an archaeopteryx is a famous fossil, very famous, only known from southern Germany. It's been known for about 160 years. There are only about 14 or 15 skeletons that have ever been found. But in the same rocks, there are thousands of pterodactyl skeletons that have been found. That goes to show you how thoroughly embedded the pterodactyls were in the skies when the first birds evolved. But if you fast forward to the end of the Cretaceous, the next interval of time, the age of T-Rex and Triceratops, you still have birds and pterosaurs. But now there's all kinds of birds, including primitive ones that still had teeth and tails and claws, but also very advanced ones that had beaks and that had big chest muscles that they could flap their wings with for long periods of time and hollow bones and fast growth and warm blood and metabolism and so on. And there were many more birds than pterodactyls. And then that world was rudely interrupted by the asteroid. And that's what ended up properly killing off the pterodactyls. It wasn't birds out competing them or pushing them aside. The asteroid is what got rid of the pterodactyls. And if the asteroid never hit, maybe there would still be birds and pterodactyls living together today. So I want to hear more about why the asteroid killed the pterodactyls and not the birds. But you said something fascinating. You said half bird, half dinosaur. But birds are dinosaurs, right? So what makes something a bird? What are the quintessential birdie features? What would your six-year-old complain about? Great question. This is so when I was writing the story of birds, when I was writing the book, I often had Anthony's voice in the back of my head saying, make sure I explain this so I don't get the, yeah, but what about this question? And I was reading it to him. So when I say Archaeopteryx is half bird, half dinosaur, what I really mean is that it has advanced features of modern birds, things that it used to fly, like as feathers and wings. But it also had a lot of features of the raptor dinosaur ancestors of birds, like the teeth and the sharp claws and the long tail. So that raises the question of then what makes a bird a bird? And look, I don't think anybody out there, not to offend anybody, maybe there's a few of you, but most people listening to this probably do not want a long, tortured discussion of names and nomenclature and how we label stuff and how one scientist thinks this, but another scientist has an alternative naming system. When it comes down to it, bird is a vernacular term. It's not a formal scientific term. There are plenty of formal scientific names, avies and avialae and neornithes, and these groups on the tree of light that have formal scientific definitions. But when it comes down to it, most scientists, not all because we do use words differently, even those of us who specialize in studying these things. But most scientists, definitely most paleontologists would say, we're going to start calling something a bird if it can do that most bird-like thing. And that is if it had wings that were big enough and that could move in the right way, that it could flap those wings and it could support itself in the air, it could generate lift and thrust. Archaeopteryx is the first fossil that we have in the fossil record that can do that. It had big enough wings that it could power its bodies through the air, and that's really a matter of physics. But can't pterodactyls do that also? Yeah, pterodactyls could, but they evolved totally separately from a totally different group, the same way bats did. And their wings are very different. We know that because the wings of pterodactyls are nothing like the wing of a bird. A wing of a bird is an arm, a heavily modified arm. You have the normal arm bones, but the hand is all fused up, and the hand and the arm bones support an airfoil of feathers, of quill pen feathers. A pterodactyl wing is a single long finger, the fourth finger, the ring finger, that anchored a giant cell of skin. Wow. Crazy. Totally different. Now bats do something even more different. Their entire hand is expanded and anchors a skin membrane. So because the wings of the three groups are so different, that's how we know that they evolved differently. But to circle back to Archaeopteryx, it's the first fossil, the oldest one we know of, that had wings made of feathers that were big enough that it could flap them and keep itself up into the air. There were plenty of raptor dinosaurs that also had wings made of feathers, but they were small, too small, which really means that wings must have evolved for something other than flying, which is a trippy thing to think about, of course, because we think, what do wings do in a bird? Birds use wings to fly, just like an airplane uses wings to fly. But that doesn't mean wings evolved for that purpose, because birds use wings for many other things, too. They use wings to protect their eggs in the nest. They use wings to keep themselves warm like a coat. They use wings to display, to attract mates, to intimidate rivals. And so we actually think that the first wings in dinosaurs probably evolved as display structures, made up of these feathers that had originally evolved as integument, as a coat, a coat of little hairy bristles to keep these dinosaurs warm. And then some of those dinosaurs modified those simple feathers into wings made of quill pens, but those first wings were quite small, used for display, and then only later on were some of those display wings co-opted to form an airfoil. So in that way, the origin of flight in dinosaurs really was an accident. That's true really of all evolution when you think about it. There's no grand plan about any of this, but something as profound as flight, such a new, powerful, revolutionary behavior, it just kind of developed when it could, because you had these small dinosaurs that their bodies had gotten small for who knows why, maybe just to hide more easily, or because of their metabolism or whatever. Those bodies had feathers on them to stay warm. Some of those feathers were elaborated into display billboards to attract mates and intimidate rivals. And at some point, if those billboards became big enough relative to the size of the body, just by the laws of physics, if those dinosaurs were moving them around a little bit, they'd generate a bit of lift, a bit of thrust, and that's when natural selection could take over and modify those wings into ever better airfoils. And that's really probably how flight developed, and things like feathers and wings, they did not evolve for flying. There was no grand plan there, but they came together to form a flying machine. And the way I like to think about it is, we think about airplanes and aircraft, the humans have invented. The Wright brothers, they made the first airplane that could fly, but they didn't invent the propeller, they didn't invent the wheel, they didn't invent the wing, they took these components and put them together in a new way, and evolution does the same thing. And with dinosaurs and birds, you had all this evolution of dinosaurs, and what emerged from that was this peculiar group of small, feathery wing dinosaurs that could flutter about in the air, and that is the origin story of birds. I love understanding how these things come together and why the transitionary pieces of it exist for other reasons. Super fascinating. I also want to understand a little bit more sort of the story in your mind of how flight itself began. Like, I get that you have these proto wings which develop for other reasons, but it's not like some Tuesday afternoon, a dinosaur was like, oh, if I do this, wow, now I'm soaring through the skies, right? Is it like little hopping and little gliding, which then gives them some benefit, and then they get better and better at that and stronger and stronger? It's a great question, and I will be direct and upfront and say we don't know the answer to that. We have some different theories, some different ideas, but ultimately this was something that happened over 150 million years ago, we weren't around to see it. What we do know is that feathers first evolved as very simple little hair-like structures, so they could not have evolved for flying because, I mean, we can't use our hair to fly, so these dinosaurs couldn't have either. We also know that the first wings were too small to be used for flying just by the laws of physics, and so wings must not have evolved for flying either. So those are things that we do know with quite a lot of confidence from the fossil record. What we don't really know is the exact setting, the exact situation where these feathery winged dinosaurs started to move those wings in a way that they could get lift and thrust. Was it that they were running quickly on the ground and they were using those wings to maneuver and to turn and to break, and they started to get a little bit of lift and started to defy gravity? Or could it have been they were living in the trees and they were jumping between branches and they were using those wings as a parachute to manipulate gravity? Or could it have been something totally different? I mean, some birds used their wings to swim. Who's to say some dinosaur with little wings wasn't using them as paddles in the water and that generated some pressure from natural selection? I mean, we don't know for sure, and I think we have to be humble in the face of the fossil record that when it comes to exactly knowing how certain behaviors originated, oftentimes we're not going to know, but we know the components, we know the general story. The general story is the things like feathers and wings which birds need to fly today, they did not evolve for that purpose. They evolved for something else initially and they were later repurposed by evolution. And that's, I think, the best we can really do at this point. Now, of course, we always need more fossils and if we ever can confidently find fossils of those very first dinosaurs that we're moving about in the air, that would tell us more, you know, where those fossils are from. Were they animals living on the ground or do they come from a forest and they were in the tree? You could start to narrow it down if you had a perfect fossil record, but we're far from that. That's why we're always looking for more fossils. In the last year, there have been some really exciting new discoveries in China of fossil birds, basically the same age as Archaeopteryx, about 150 million years old in the Jurassic period, but they're quite different from Archaeopteryx. So there are new fossils out there that are emerging as we speak that are not challenging the overall story that birds evolved from dinosaurs or that feathers and wings evolved for other reasons before flight, but are helping to refine those hypotheses that we have about exactly how flight evolved. So there's a lot of exciting work still to come as all of these different farmers in China and young students and scientists in China are going out, finding fossils and studying these new fossils. I don't want to get us too far off track from getting back to the like, how did the bird survive the asteroid, but- Oh, that's right. That's what we were going to talk about. Right, but, but, but I was so excited when reading your book that we actually know what color some of these feathers were, not just on birds, but on like, you know, earlier dinosaurs. Can you tell us a bit like, how do we know what color they were when we actually can't see the color in the fossils? It sounds impossible, doesn't it? It really does. And I remember when I was in school in the late 80s and early 90s, you know, growing up in, you know, out of Illinois, middle of farm country, my, my charming little hometown, I remember learning in school these lessons on dinosaurs and, and we would be told things like in, in the books, you know, that, well, there's some things about dinosaurs we'll never know. We'll never know what colors they were. Were they green? Were they brown? Were they purple and pink polka dot? And we just won't know because color doesn't preserve as fossils. Well, the most dangerous thing you can ever say is that we will never know. Especially to a scientist. And so I try to never say that because you don't know what you're going to find. And what happened was about 20 years ago, there was a student, a really remarkable student, Jacob Winthers, his name. He's now on the faculty in Bristol, but he was a student at the time. And he was studying this fossil squid. And he noticed that near this fossil squid was this patch of really dark black stuff. And he said, you know, the obvious thing is this stuff ink. Is it ink? I mean, it, you know, it makes total sense. And maybe if it was the senior professor looking at that, maybe they would have been embarrassed to say, but he was a student, you know, completely open mind, completely uninhibited. Is it ink fossilized ink? And so how could he tell? Well, he looked under the microscope and high power microscopes and whoa, lo and behold, it looked just like modern squid ink when he looked under the microscope because it had these little bubbles inside these things called melanosomes, which hold pigment. And you can tell different colors are formed by different types of melanosomes of different size and shapes, not all colors, but colors like black and brown and gray and ginger and some of the iridescent shiny colors. And so he realized that in some cases, you can get these little pigment vessels preserved for tens of millions of years as fossils, which then led him and others to say, well, wait a minute, if we can see this in a squid, what about some of these dinosaurs with feathers that are coming out of China? Let's look at these under the microscope and lo and behold, there were melanosomes in the feathers, not in every feather, but in the best preserved ones. And they could map those melanosomes, the size and the shape of them, to known colors, because this is all just physics, it's optical physics. And so, okay, this feather has melanosomes in it that the size and shape of ones that we know give a brown color in modern birds, or they give a ginger color. And so from there, they were able to start to tell the color palettes of some of these dinosaurs. And what that does tell us is that some of these dinosaurs with feathers that were they were not birds yet, they were not they didn't have big wings, they weren't flapping those wings, they couldn't fly, but they had quite elaborate feathers, feathers that were very colorful, really ostentatious patterns to them. Almost certainly they must have been using these for display to attract mates to intimidate rivals, the same way that so many modern birds do with their feathers. So it was this realization that helped build this hypothesis that wings first evolved for display, and were later co-opted as airfoils for flying. We don't know again for sure that's exactly what happened, but the fact that you have small wings in these dinosaurs too small to fly, and those wings have these really gaudy color patterns to them, it just makes sense that they were using them for display. And I think this is incredibly exciting. It's so cool. It's so neat, isn't it? This is science. This is. It's wonderful when physics comes to the rescue, right? If physics came to the rescue. Oh, you were waiting for that, Daniel. Oh my goodness. And it's not the first time in paleontology physics has come to the rescue, I must say. It happens in every story. Oh, don't. But just to be clear, we're not seeing the colors in the fossils, right? We're seeing traces of different shaped mechanisms that produce those colors. So it's one step indirect. In most cases, that's true, but occasionally sometimes there's so many melanosomes that are so well preserved, probably because the feather was buried really quickly, that you actually see bands of color in those feathers. They wouldn't be exactly like in the living bird, but they're there visible to the naked eye, these bands of different colors, which is just fascinating. Just incredible. I love that you call it ostentatious. Like, if you got into a time machine and went back and saw the first birds, you'd be like, I'm sorry, that's a bit much, isn't it? Tone it down. It would be, it's like Liberace, you know, John Schiff in the 70s. Like, that's how I imagine these things. Just full on, just total, total full on, just going for it, just visual display, boom, in your face, trying to get noticed, trying to show how attractive they are or how scary they are to their rivals. That was probably what drove much of the evolution of birds initially. So you're saying that birds through their whole history have been absolutely fabulous? They have been and they remain absolutely fabulous. Absolutely. All right, we are going to take a break and when we get back, y'all are going to be so proud of us because we are actually going to answer the question we set out to answer like 15 minutes ago. What determined who survived the giant, cretaceous asteroid? Switching to Virgin Media's lightning fast broadband is easy. We'll handle everything for you. That smooth broadband and smooth switching. Smooth like a walrus on a speedboat, powering through open, stewardly waters. Yeah, that smooth. Visit virginmedia.com. New customers only, virgin fiber areas, restrictions and credit checks apply. No set up fee online only, terms apply. We are back in 66 million years ago. A giant asteroid struck the earth during the cretaceous. We had pterosaurs. We had dinosaurs. We had birds, which we've learned are also dinosaurs, but are maybe not what we first think about when we hear the word dinosaur. Steve, who survived and why? Or first, actually, what was it like when that giant asteroid struck the earth? Hell, it was like hell, total hell on earth. And with no hyperbole, I mean it, it was probably the single worst day in the history of earth. This was not a normal day. This would have started like any normal day. And then all of a sudden, out of nowhere, out of the outer reaches of space, came this six mile wide rock, just fell out of the sky. And the animals that were living then had no idea it was coming. They had no way to monitor the motions of the heavens. You know, I've read some reconstructions of this asteroid, and there's some that suggest that it did two passes, like it made a near miss of the earth and went around the back of the sun and then came back and hit the earth. So if dinosaurs had done their astronomy, they would have had some warning. Okay, but Daniel, fund science. That's the lesson, fund your scientists. So hopefully we've learned our lesson there. And hopefully the next time an asteroid confronts us, it does a double pass just to show us it's there. But imagine though, so T-Rex was there the day this happened. Okay, Triceratops was there. There were giant duck-filled dinosaurs and long neck dinosaurs and all kinds of dinosaurs. There, we know that from the fossil record. We have fossils of these dinosaurs going right up to the layer in the rock that is marked by all the chaos of the asteroid. And just imagine your kind, your dinosaur family has been dominating the world for over 150 million years. You've been at the top of the food chain, different species in different places, but top of the food chain, the biggest meat eaters, the biggest plant eaters, all kinds of diversity, and then all of a sudden this rock falls out of the sky. This thing is traveling, you know, well more than 10 times faster than a speeding bullet, probably much faster as the physicists here could, could tell me. And when it hit the earth, it released more than a billion nuclear bombs worth of energy. It punched a hole in the face of the earth over 100 miles wide. And that's the crater that we can still see part of in Mexico. Most of it's covered by the Gulf of Mexico, by the water, but some of it does lap onto the land in the Yucatan, near Cancun. This was catastrophic. This was the biggest asteroid that's hit the earth in at least the last half a billion years. This was not a normal visitor from space. And the energy at release was so profound that it triggered earthquakes and wildfires and tsunamis. And you had all this destruction in the minutes and the hours after the asteroid. And a huge number of animals would have died if you were outside and exposed to the fires and to the scalding rain of all the stuff that was liquidized by the collision that then fell back down as these scalding glass bullets. And then there was acid rain that came down a little bit afterwards. And this was a disaster movie. This was, I mean, the weirdest, worst, kitschiest disaster movie you've ever seen. Even worse, probably, than that. And the worst part, though, was not the immediate carnage. It was what happened over the next few years because all the soot from the wildfires, from the smoke, a lot of the dust and dirt and grind from the collision, the pulverized rocks and so on, went up into the atmosphere, spread around in the currents of the high atmosphere and blocked out the sun for at least a few years, maybe up to a decade or even a bit more. And so the earth would have gone dark and cold. Even in proto-California? Everywhere, probably. There could have been little bits poking through, poking through. But it seems like really, this was a time of coldness and darkness. And we see it in the rock record. We can see some of the chemical proxies that tell us about temperature. You can see how temperature took a nosedive. You can see a lot of the soot and stuff from the wildfires actually in the rock record, right marking that extinction. So if the earth went dark and cold, even if it was just for a few years, I mean, plants would not have had sunlight to photosynthesize, nor would the phytoplankton in the ocean. And so ecosystems would have collapsed as sunlight was starved from the plants in the plankton. And these ecosystems collapsed like houses of cards. The plant-eating animals didn't have anything to eat. They died. The meat-eaters didn't have anything to eat. They died. And 75% of all species died. Three out of every four species, period, did not make it through and died quite quickly. We don't know if they were all dead within a year or five years or 10 years or whatever, but we do know from really well-dated fossils that within a few tens of thousands of years at most after the asteroid, 75% of stuff was gone, including all the pterodactyls, including all those reptiles that were living in the water, including the ammonites, those beautiful coiled, shelled sea creatures, and including every type of dinosaur except for one peculiar group of birds. And these were the modern style birds, the ones that had big wings and huge chest muscles to power those wings, the ones that had beaks instead of teeth, the ones that had really lightweight hollow skeletons, the ones that grew super quickly that went from a hatchling to an adult within a year at most. Only those birds survived. There were a bunch of birds that still had teeth and claws and long tails that were there flying over the head of T-Rex the moment before the asteroid hit, and they would not make it through. So the question really is why were those birds so special? And I think when it comes down to it, they just held a winning hand of cards. When something changes so quickly, and the environment changes so quickly, you don't have time to adapt the normal processes of natural selection through random mutations shaping your genome over the generations. You have to confront that disaster with whatever hand of cards you're holding. And dinosaurs like T-Rex and Triceratops, they had been utterly dominant for tens of millions of years, but now all of a sudden, they were in trouble because they were big. They needed to eat a lot of different types of food. Some of them needed to eat a lot of plants, hundreds of pounds of plants a day. It took them a long time to grow from babies into adults. It would take a T-Rex like 20 years to grow into an adult. That's a long time to survive if the world has gone to hell. And they couldn't hide very easily. How could a T-Rex dig a burrow to hide itself away? Or how could a Triceratops just go and find a cave to hunker down in? It'd be really tough. So the animals that survived were ones that tended to be smaller, that could hide away more easily. They're ones that grew quickly. They're ones that reproduced quickly. They're ones that didn't need a lot of food. And when it comes to birds, one particular thing that allowed them to survive, it seems, was their beaks. Because this was just some little trivial factoid about these birds. There were plenty of birds that still had teeth, but some birds had beaks. All right. But when it came to that asteroid, changing the rules of the game, all of a sudden, basically everything's dying. The forests have collapsed. There's no more leaves and stems and fruits and flowers to eat. All that stuff is gone. The plant-eating animals, they die. The meat-eating animals, they die. What is left? Well, one of the things that survives longest, and we see this today, if there's a volcanic eruption or a wildfire, everything might be obliterated, but seeds can survive. And they do survive quite long. They won't survive forever. But if you have to get through a few years or so, if you can eat seeds, that can be your ticket to survival. And those birds with those beaks. I can eat seeds. I love seeds. Yeah. So there you go. So remember this. We got to remember this. When the nuclear apocalypse comes for us, eat your bird feed. That was such an inspirational speech. I felt like you were the president in Independence Day saying, if we can eat seeds, we can all survive. I got chills. Yeah, me too. So if you take anything away from this conversation, any of you guys, well, first of all, if you take anything away, go out and, of course, buy my book and leave five-star reviews online. Story birds. Anyway, take that away. But the second thing, take away. Eating seeds can help you survive in apocalypse. And it probably did at the end of the Cretaceous. Something as trivial as that, which seems so trivial that in the moments before the asteroid hit, it would have meant nothing. It's just something you ate. It's like that's what your species was adapted to do, and that's what you ate. Other things ate leaves and other things ate fruit and other things ate meat. But then everything changes. Seeds were the only thing left, and all of a sudden, that was your ticket to survival. But what's the connection between seeds and beaks? Because again, I can eat seeds and I don't have a beak. Yeah, we can eat seeds just because we as humans are so omnivorous, and our teeth are quite good at eating lots of different things. But actually, we're quite unusual to be able to eat so many things. And it's not that like, you know, no other dinosaurs could ever eat seeds, but beaks are really optimized for cracking seeds. They're like the best way you can eat seeds. We could eat more seeds if we had a beak instead of our teeth. So and then of course, things like T-Rex would not have been eating seeds. So it was just one of those things. It's not that birds were the only animals that could eat seeds. Some of the small mammals probably did as well. That's probably why they made it through. But it's just probably one of the reasons. And when it adds up to it, it's really, again, the hand of cards you're holding. It's birds. Some birds, again, most birds died, all the ones with teeth and long tails and claws, they died with T-Rex and triceratops. It's only the modern style birds that survived. And they had beaks, they grew fast, they could fly really well, so they could escape any local danger fairly easily. They were small, they could hide away fairly easily. They lived on the ground or in the water, they didn't live in the trees. So when the forests collapsed, they weren't nesting in those trees, their homes didn't disappear. So all of those things, when you add them together, it just gave birds a royal flush. And that's what they had to confront the asteroid with. And they made it through. But if small little things were different, little twists of fate or circumstance, playing out in the minutes, the hours, the days after the asteroid, everything could have been different. And who knows what the modern world would have looked like. Who knows what would have made it through to survive, to repopulate the world. So I read this other really great book called The Rise and Rain of the Mammals. Oh, that's a fantastic book. Oh my gosh. That is so good. Five stars. Five stars. It's maybe the second greatest book in the world, except for the story of birds. You can guess who wrote that book. The Rise and Fall of the Dinosaurs is also in the ranking there. They're great, but you know what? None of them won a Royal Society Book Prize. You have the title here. So of course, all of your readers know your book, the city of Mars. I don't have to pitch it. Well, the story of birds is going to be this year's winner. That's what I'm predicting. Well, I hope you're on the panel. Okay. Thanks. Thanks. But I hope we remember to submit it to the prize. That's the first thing to get a prize. There you go. Send it in. Send it in. Okay. But to get back on track. So, you know, there were mammals who made it through. And there were probably some like, you know, there must have been some like reptiles who made it through. Is eating seeds like a common denominator for all of the animals that made it through that weren't birds? Not for every animal that made it through. So about 25% made it through. And there were some other ways that you could make a living too. Some of the animals that survived, things like crocodiles and turtles, they lived mostly in swamps and in ponds and in rivers in shallow water in ecosystems that did not have plants or other photosynthesizing organisms at the base, but instead were detritus-based ecosystems. So it was basically eating decaying crap that's at the base of those food webs. Buffet time. After that asteroid hit, perfect. It was a global buffet if you were in those ecosystems. So you had fishes that would eat that stuff, and then the turtles and crocodiles would eat them and so on. So that was another ticket out of the chaos. So it wasn't just only eating seeds, it was the only way you could survive, but it was one pathway to survival and there seemed to have been others, but there were limited pathways to survival. And really nothing bigger than like a Siberian husky dog made it through, at least on land. So size, even if you could eat seeds and you were bigger, you were probably in trouble because it took you too long to grow into an adult and you needed to eat too many seeds to power your metabolism. So being small, really more than anything, was the number one thing you needed to be to survive. And I mean really small. Like something that could fit in the palm of our hands is the best probably body size to be that or smaller. And we had ancestors. We had tiny little shrew-sized furry mammal ancestors that also stared down the asteroid, made it through, and that's why we're here. We've been having too much fun, so we don't have time for my questions about the terror birds or the demon ducks or loss of flight. That is a shame. You know what they're gonna have to do. Get your book. Read the book. Absolutely. We always need to leave people wanting a little bit more for these conversations. So the second half of the book is all about what happened after the asteroid and how modern-day birds established themselves. So many of the birds we know today, the familiar birds, songbirds and parrots and different types of water birds and penguins and hawks and so on, they established themselves very quickly after the asteroid as part of the recovery. This was a wide-open world. Endless opportunities were out there. And evolution went into overdrive and you had all these new types of birds. So I tell that story in the book. And evolution went so wacky that you got these incredible birds like terror birds, which stood taller than a human, that were basically like a T-Rex reincarnated. These things became the top predators in South America. They had heads the size of horses, big sharp beaks, not for eating seeds. No, no, not these beaks. These are for ripping flesh. Heads the size of horses heads or heads the size of horses? Heads the size of horses heads. Yeah. Yeah, not a head the size of a thoroughbred. What a head the size of a thoroughbred's head. Yeah. But still, pretty terrifying. And so I talk about these, you know, elephant birds and demon ducks. Imagine a duck supersized by a hundred times the size and it's demonic, but not really because it was a plant eater and these things lived in Australia for tens of millions of years. Until quite recently, our human ancestors ate their eggs. We find cooked demon duck eggs and archaeological sites and campfires. So we had human ancestors and cousins that confronted some of these birds. And there's so many more. There were once birds that soared on the thermals of the world like giant kites with wingspans of over 20 feet wide. A huge, fantastic aviary of extinct birds are out there. We only know them from fossils. I try to do them justice later on in the book. So there's a couple of chapters on those and then of course about how some of those birds lost, gave up the very essence of birdness. They gave up flying. Ostriches and cassowaries and emus and penguins and so on. They gave up flying so they could become adapted to other niches in the ecosystem. So they could become bigger, so they could become giant bulk feeding plant eaters. So penguins could go into the water and become big fish eaters and so on. There's a lot more. But again, I need to leave you all wanting more. So it's all in the story of birds. I promise it's all in there. And there's a whole lot of great stories about all the amazing things birds have done. And I think when it comes down to it, we just need to appreciate birds. They're fantastic diversity. There's over 10,000 species of birds today. That's about double the number of mammals. So yeah, okay, dinosaurs died. Dinosaurs went extinct. It's now the age of mammals. Well, there's still like double the number of dinosaurs as mammals in the world today by that metric. So when you look out and you see a magpie or a pigeon or a sparrow, I mean, you're looking at a real true dinosaur that's made it to the modern day. And I hope that comes through in the book. That's what I really want to convey. Well, I have a question for you from my wife who's a biologist. She wants to understand how birds prepare for migration. Apparently, they put on a huge amount of muscle and their stomachs shrink to almost nothing. So her question is, what's the secret and how do we follow the bird dinosaur diet ourselves? Well, we're out of time here. So I don't know. I don't know. There's so much about birds I don't know, especially when you get into the amazing things birds do today. Once you get into their migrations and their feats of cognition and intelligence and their songs and these kind of things. I know a bit, I write about a little bit towards the end of the book about a few of these things. But there's so much I don't know. I have no idea how birds are able to prepare for these migrations. It is otherworldly to me, but it's one of those things that we just must admire about birds. So I'm sorry to let your wife down there. I don't have any like top nutrition tips of how to be a bird, you know, marshal the power of migration to become more fit and energetic. If you find out, let me know. That's just an idea for your next book. Well, then let me ask you a different question. If you went to an alien planet, right, you're on board the ship or landing on a planet, we think there's life on there. Are you expecting there to be birds or life in the air? How broad do you think this sort of evolutionary niche is? Well, I'd be curious to hear, you know, Kelly's view on this. So somebody actually knows something about outer space and different planets and life, potential life on other planets and settling other planets. I mean, when it comes down to we just don't know, we've never found any fossils, definitive fossils of any life anywhere else. But I'm guessing that at some point in our lives, there's going to be a fossil from Mars that is found. Until then, though, we just don't know very much. But I would think that if you do have other worlds out there that are anything like Earth, there's going to be stuff flying around. This is a whole environment that's there to be colonized, if you want to think about it that way. And over time, evolution, it expands. I mean, it fits organisms to their environment. If there's opportunities, evolution will not in any sort of direct planned out way, but it will over time really just fill the space and find ways to exploit resources and environments and ecosystems. And the air is vast. There's air all around us. And that's just a place you can live and a place that you can get shelter and a place where you can start to form ecosystems and communities. So yeah, I would expect the air elsewhere would be settled the same way if there's liquid water elsewhere or dry land elsewhere, that it would be settled in a similar way. But who knows really, Kelly? I don't know. What do you know what you're talking about? I'm just blathering Daniel always ends our interviews with a question about, do you think you'd find the same thing on an alien planet? And so I will say nothing. This is Daniel's prerogative to ask our interview, E, this question at the end. And so I will just say that Steve, it was amazing having you on the show. I loved reading the story of birds and the illustrations were great and the photos were fun. I highly recommend that everyone head out and get the story of birds, which comes out today. Thank you guys. Thank you so much. This is so much fun. We could have done this for hours, but we'll have to do it again. Yes, we will. Yeah. And I have a bunch of listener questions that I think you are the guide answer. So I hope you'll come back. Well, let's, we will circle back. Absolutely. Keep track of those questions. I love just being thrown random questions like the stuff Daniel's been asking me. So let's do it again. All right. Well, I'll hold you to it. Until next time. Thanks everybody for listening. Please go and do us a favor and rate the show on whatever podcast app you're using. It really helps people find us. Daniel and Kelly's extraordinary universe is edited by the amazing Matt Kesselman. He really is a wizard. You can also find us online on Blue Sky, Instagram and X, the and K universe. Come engage with us. You can email us at questions at Daniel and Kelly.org. We really do want to hear from you. And you can find our website, www.DanielandKelly.org, where you'll also find an invitation to join our discord where everybody comes and talks about the amazing universe. And we also have the most amazing moderators. This is an I heart podcast. Thanks for joining us. This is an I heart podcast guaranteed human.