Speaker 1: Hey, welcome to Sign Stuff, a production of iHeartRadio. I'm
Speaker 1: hoor hitchhim, and today we're answering the question did dinosaurs
Speaker 1: have feathers? You might think you know the answer to
Speaker 1: this question, but as we'll learn today, the real answer
Speaker 1: has changed significantly in the last few years. To get
Speaker 1: the full story, we're going to talk to a couple
Speaker 1: of paleontologies. We're going to tell us what we know
Speaker 1: about the origin of feathers, which dinosaurs had them, and
Speaker 1: why feathers evolved in the first place. I promise by
Speaker 1: the end you want to look at dinosaurs or feathers
Speaker 1: the same way again. Enjoy. Hey everyone, So I picked
Speaker 1: today's topic to celebrate the release of my news book,
Speaker 1: Oliver's Great Big Universe Evolution Changes Everything. It's all about
Speaker 1: the history of life on Earth, is told by a
Speaker 1: kid named Oliver. It's a great book for those smart
Speaker 1: kids in your life, your nieces or nephews, your friend's kids.
Speaker 1: I promise, if they like funny stories and you think
Speaker 1: they might like science, I think this might be their
Speaker 1: favorite new book series. So please check it out at
Speaker 1: Great Big Universe dot net or your favorite bookseller. All right,
Speaker 1: let's talk about dinosaurs and feathers. Now, I'm excited for
Speaker 1: today's episode because we're gonna hear from two paletologists, one
Speaker 1: of whom was involved in the landmark discovery that put
Speaker 1: the origin of feathers way further back in time than
Speaker 1: anyone expected. But before we get there, I thought it
Speaker 1: was important that we covered the basics first because that's
Speaker 1: going to help us later in the episode. And the
Speaker 1: first question we're going to ask is what exactly is
Speaker 1: a dinosaur? You probably think you know, but according to
Speaker 1: our first expert, the answer is not that simple. Well,
Speaker 1: thank you, doctor O'Connor for joining us today.
Speaker 2: It's absolutely my pleasure. I'm a big fan, so I'm
Speaker 2: happy to be here.
Speaker 1: Awesome. Can you please tell us who you are and
Speaker 1: what you do.
Speaker 2: My name is Jingme O'Connor, and I'm the associate curator
Speaker 2: of Fossil Reptiles at the Field Museum of National Street
Speaker 2: in Chicago. It's just a fancy complicated way of saying
Speaker 2: that I'm a nerdy dinosaur paleontologist.
Speaker 1: I guess maybe for people who are not super familiar.
Speaker 1: He tell us what exactly is a dinosaur? Like what
Speaker 1: makes a dinosaur a dinosaur.
Speaker 2: Well, okay, that's not an easy question to answer. So
Speaker 2: dinosaurs are basically a group of animals that have a
Speaker 2: common ancestor. So, for example, all living mammals have one
Speaker 2: common ancestor, that's why they form a true group. And
Speaker 2: mammals are characterized by a specific set of traits that
Speaker 2: you can then use to identify that they're mammals, like
Speaker 2: milk and fur. But if only it was so easy
Speaker 2: with dinosaurs. Unfortunately, dinosaurs are really weird and different, and
Speaker 2: until recently we would have said things like dinosaurs have
Speaker 2: a completely open hip socket and a bunch of traits
Speaker 2: that for a long time really did define dinosaurs. But
Speaker 2: then the more we find close relatives of dinosaurs, all
Speaker 2: those traits we used to use suddenly got blurred. We
Speaker 2: found that they were present in close non dinosaur animals,
Speaker 2: or they were absent in the oldest known dinosaurs that
Speaker 2: we started to find.
Speaker 1: All Right, what doctor O'Connor is saying is that the
Speaker 1: definition of a dinosaur is not an animal that looks
Speaker 1: a certain way or as a certain characteristic. It just
Speaker 1: means all the animals that came from one specific common ancestor. Because,
Speaker 1: as it turns, out, dinosaurs have cousins. Not every big,
Speaker 1: cool giant reptile is a dinosaur. For example, there are
Speaker 1: the big reptiles that eventually became crocodiles. Crogs did not
Speaker 1: come from dinosaurs. Or those giant swimming reptiles like Ichiosaurus
Speaker 1: or plesiosaurs that you see swimming around in the Jurassic
Speaker 1: Part movies. Those are not dinosaurs. There's a big one Terosaurus.
Speaker 1: These are the giant flying reptiles that you also see
Speaker 1: in movies, like pterodactyls or Terranodon. But the giant wings
Speaker 1: and the long deaks dose are not dinosaurs either. They're
Speaker 1: more like cousins of dinosaurs. So when you're talking about dinosaurs,
Speaker 1: you're really talking about a specific family of animals that
Speaker 1: came from one specific ancestor.
Speaker 2: Let's just say that the ancestral dinosaur was probably a small,
Speaker 2: warm blooded bipedal, probably carnivorous or omnivorous animal.
Speaker 1: So scientists think the first dinosaur, the ancestor of the
Speaker 1: animals we call dinosaurs, probably walked on two legs, kind
Speaker 1: of like Terrannosaurus REGs or the veloscy raptors that again
Speaker 1: you see in the Jurassic part movies. But here's a
Speaker 1: confusing part. Some dinosaurs branched out and went back to
Speaker 1: walking on four legs, and that's where you get some
Speaker 1: of the they're famous dinosaurs like Triceratops or the one
Speaker 1: with the really long neck, Brachiosaurus. All Right, I promise
Speaker 1: this will all be useful later. Now let's get to
Speaker 1: the other basic which is what exactly is a feather.
Speaker 3: So my name is Maria McNamara and I am professor
Speaker 3: of paleontology at University College Cork in Ireland.
Speaker 1: Can you tell us what a feather is?
Speaker 3: Ah, that's an interesting one. So a feather is basically
Speaker 3: an integumentary appendage, to give it its scientific term. It's
Speaker 3: basically made of protein, a protein called keratin. It's the
Speaker 3: same protein that makes up our hair and nails, and
Speaker 3: it is actually the most complex sort of tissue structure
Speaker 3: that is known in vertebrate animals. Each feather has a
Speaker 3: central sheaft with lateral side branches, and those branches have branches,
Speaker 3: and actually the branches are organized in a spiral around
Speaker 3: the shaft. So a feather is really the most complex
Speaker 3: tissue structure that is known.
Speaker 1: From the skin all right, you probably already knew what
Speaker 1: a feather was. But here's the thing. That description of
Speaker 1: feathers only applies to modern feathers. Early feathers, scientists think
Speaker 1: we're a lot simpler. They look more like hairs, except
Speaker 1: they're not hairs. How are they related to hairs?
Speaker 3: What feathers and hair have in common is that they're
Speaker 3: both outgroots from the skin, and they're both made of
Speaker 3: keroten protein. But that's where the similarity ends because hairs,
Speaker 3: unlike feathers, they don't branch, and hairs are solid. If
Speaker 3: you slice through a hair and look at us onto
Speaker 3: the microscope, you'll see a solid cylinder of keroten protein,
Speaker 3: whereas if you slice through a feather, it's hollow in
Speaker 3: the middle. So that's one major difference. And also in hairs,
Speaker 3: we have a form of keratin called alpha keratin. Alpha
Speaker 3: kerosin forms a helix, but the kerosion that's in feathers
Speaker 3: has traditionally been called beta keratin, and that looks like
Speaker 3: a corrugated tin roof, so it has an up and
Speaker 3: down zigzag corrugated pattern. So the structure of the proteins
Speaker 3: is very different.
Speaker 1: It makes hair sound a lot more boring.
Speaker 3: Hair is still a very interesting structure, but structurally it
Speaker 3: is simpler than feathers.
Speaker 1: So when we talk about dinosaurs, now you know what
Speaker 1: we mean. And when we talk about feathers, you also
Speaker 1: know what we mean. And now we get to the
Speaker 1: question did dinosaurs have feathers? And I'll just tell you
Speaker 1: the answer to this question is kind of shocking. At least,
Speaker 1: it really took me by surprise. Where did feathers come from?
Speaker 3: Ha? If I could answer that question, I would get
Speaker 3: I don't know, a normal prize or something.
Speaker 1: Yeah, that's good, let's get you noble price.
Speaker 3: Yeah. Yeah, Well, look that question, where haven't you feathers
Speaker 3: come from? That's the question that's been driving our research
Speaker 3: over the last fifteen years.
Speaker 1: All right. According to doctor McNamara, the answer to the
Speaker 1: question did dinosaurs have feathers? Or where did feathers come from?
Speaker 1: Has changed several times over the last thirty years, And
Speaker 1: it's changed because we keep finding fossils that totally rewrite
Speaker 1: what we think we know. So I'm going to take
Speaker 1: you back starting in the nineteen nineties.
Speaker 3: So you know, if we were to go back, let's
Speaker 3: say to nineteen ninety, right, and if you would ask
Speaker 3: me where the feathers come from, I would have told you, well,
Speaker 3: that's easy. Birds evolved feathers. Feathers are a feature that
Speaker 3: are unique to birds.
Speaker 1: Why do you think that is?
Speaker 3: Because before the nineties, you know, they were the only
Speaker 3: modern animals for which we had feathers. We hadn't discovered
Speaker 3: any fossils at that point that preserved feathers.
Speaker 1: And so the idea is that when birds evolved, part
Speaker 1: of what made them birds was that they developed feathers exactly.
Speaker 3: We thought that feathers were one of the defining characteristics
Speaker 3: of birds. And I mean, there's other features that define birds,
Speaker 3: having a really enlarge, exaggerated sternum, to have big, huge
Speaker 3: chest muscles for powering flight. Birds have special little bones
Speaker 3: in the shoulder girdle, they have special shape of their
Speaker 3: clavical These were all thought to be defining characteristics of birds,
Speaker 3: and feathers were thought to be one of those features.
Speaker 3: We simply hadn't found any fossils that had evidence of feathers.
Speaker 1: So before the nineteen nineties, we just thought feathers were
Speaker 1: a birth thing. Modern birds were the only animals we
Speaker 1: had ever seen with feathers, so we thought birds were
Speaker 1: the ones that evolved them. That basically feathers started with birds,
Speaker 1: which was a totally reasonable thing to assume. But then
Speaker 1: something happened in the mid nineteen nineties.
Speaker 3: But then in the mid nineteen nineties, the world was
Speaker 3: literally turned up side down with the dramatic discovery that
Speaker 3: some dinosaurs also had feathers.
Speaker 1: Yes, the nineties didn't just give us grunch rock. The
Speaker 1: nineties gave us one of the most significant dinosaur discoveries
Speaker 1: in history. We're gonna talk about this discovery and how
Speaker 1: it and other discoveries changed when we think feathers evolved.
Speaker 1: Stay with us. We'll be right back, and we're back Okay.
Speaker 1: Before the nineteen nineties, we thought feathers were just a
Speaker 1: bird thing, and the story everyone agreed to was that
Speaker 1: birds were the ones that evolved feathers. But then in
Speaker 1: the mid nineteen nineties there was a discovery that rocked
Speaker 1: everything we thought was true.
Speaker 3: So in the nineteen nineties there was the discovery of
Speaker 3: dinosaurs preserved soft tissues from the early Cretaceous je Hall
Speaker 3: biota of China, and the Jehall biota is now recognized
Speaker 3: as one of the most important fossil localities in the world.
Speaker 3: So these fossils are found in northeast China, and they
Speaker 3: preserve lots of different types of animals, with everything from plants, insects, turtles,
Speaker 3: some early mammals, and lots of dinosaurs. What was discovered
Speaker 3: was a dinosaur called sinosrouptrics. So Sinus ruptrics is a
Speaker 3: small little therapod dinosaur and it's only about thirty centimeters tall,
Speaker 3: and it preserves dark organic matter, dark remains of its
Speaker 3: soft tissues around the head, down the back of the neck,
Speaker 3: along the body, and along the tail. And when the
Speaker 3: Chinese research team looked at these fossils under the microscope,
Speaker 3: they could say that that brown material it actually had structure,
Speaker 3: and that structure was that it was posed of thousands
Speaker 3: of tiny filaments, and the Chinese team surmised that these
Speaker 3: filaments were in fact a very simple sort of feather.
Speaker 1: Basically, researchers in China discovered a dinosaur with feathers. It's
Speaker 1: a tiny dinosaur, only about a foot tall, and what
Speaker 1: the fossil showed was that it had kind of a
Speaker 1: mohawk running down its back and a fuzzy tail with
Speaker 1: stripes that looks sort of like the tail of a raccoon. Now,
Speaker 1: I know what you're thinking, that doesn't quite sound like feathers,
Speaker 1: and that's why this fossil was a little controversial.
Speaker 3: Now this proved massively controversial because you know, the feathers
Speaker 3: that were all very familiar with, they have that clear
Speaker 3: pattern of branching. They have the central shaft and the
Speaker 3: lateral branches. But what not many people know is that
Speaker 3: some birds do have feathers that have a very simple structure.
Speaker 3: So some birds have feathers that are just simple filaments
Speaker 3: that don't have any branching. So turkeys, for instance, they
Speaker 3: have these weird, little spiky feathers that grow out of
Speaker 3: their chin and they are bristles. They are just a
Speaker 3: simple filament. And there's a bird called the black coucal,
Speaker 3: and the black coucal the juveniles they have feathers that
Speaker 3: don't branch. So there are modern examples of these sorts
Speaker 3: of feathers, and so the Chinese team said, these are
Speaker 3: so simple in structure, it's possible that these dinosaurs are
Speaker 3: showing us some of the very earliest types of feathers.
Speaker 1: Okay, so this wasn't a clear slam dug that dinosaurs
Speaker 1: said feathers. People thought, well, they could be hairs. Well,
Speaker 1: how do we know this are not just hairs.
Speaker 3: Yeah, so that's a very good question, and to be honest,
Speaker 3: that question wasn't answered for quite some time because really,
Speaker 3: if you want to prove that they're not hairs, you
Speaker 3: need to prove that they're hollow and not solid. So
Speaker 3: for a long time those structures were really controversial because
Speaker 3: the Chinese teams they weren't doing the sort of microscopic
Speaker 3: analyzes that were necessary to prove that they were feathers.
Speaker 3: And what was really exciting was when the dinosaur Microraptor
Speaker 3: was discovered. So this is a feathered dinosaur that preserves
Speaker 3: structures that are onlyquivocally feathers. You can't argue with them
Speaker 3: because they have the shaft, they have the lateral branches,
Speaker 3: and they even have the branches on the branches. They
Speaker 3: have the barbs and the barbules, and so those are
Speaker 3: effectively modern type feathers. They're identical to the feathers that
Speaker 3: we see in modern birds. So once Microraptor was discovered,
Speaker 3: when then there was no disputing the fact that at
Speaker 3: least some dinosaurs had true modern type feathers.
Speaker 1: All right, here's a little bit of context. We've known
Speaker 1: for a while that birds evolved from dinosaurs. If you've
Speaker 1: heard of archaep terics, if also the kind of looks
Speaker 1: halfway between a dinosaur and a bird that was discovered
Speaker 1: in eighteen sixty one. What the discoveries in China did
Speaker 1: was pushed the origin of feathers back to before archaep
Speaker 1: terics and into the kind of dinosaurs that directly evolved
Speaker 1: into birds. These dinosaurs are called therapods. So after these discoveries,
Speaker 1: people thought, wow, feathers didn't start with birds. They started
Speaker 1: right before birds, in the dinosaurs that evolved into birds.
Speaker 3: So then you know our concept of rock feathers were
Speaker 3: and where they came from. We felt, well, maybe feathers
Speaker 3: are something that evolved in birds and they're very close
Speaker 3: dinosaur relatives, that they were something that evolved just in
Speaker 3: the bird like dinosaurs the therapods, and that's what we
Speaker 3: thought for pretty much twenty years.
Speaker 1: So for twenty years that was the story. Did dinosaurs
Speaker 1: of feathers? The answer was yes, a few dinosaurs, the
Speaker 1: ones that directly evolved into birds, had them, and that's
Speaker 1: when feathers started, but then that all changed in twenty thirteen.
Speaker 3: But then in twenty thirteen, we discovered a completely different
Speaker 3: type of dinosaur that's not related to the birds like
Speaker 3: dinosaurs at all, and each had feathers.
Speaker 1: Okay, let's get to the big twenty thirteen discovery. What
Speaker 1: doctor McNamara and her colleagues found was another dinosaur with feathers,
Speaker 1: but this one was different.
Speaker 3: It's an Ornithiskian dinosaur, so in the same family as
Speaker 3: viserah Thops and ankylosaurs, you know, these big, lumbering kind
Speaker 3: of beasts. So we found a quart repeated dinosaur, a herbivore.
Speaker 3: Each had feathers, and it didn't just have one type
Speaker 3: of feathers, it had three types of feathers, So that
Speaker 3: really rocked the world.
Speaker 1: What they found was a dinosaur they called Colinda dromuse,
Speaker 1: and it had hair like feathers on its head, chests,
Speaker 1: and legs. And what's significant about this dinosaur is that
Speaker 1: it's on a totally different branch of dinosaurs than the
Speaker 1: dinosaurs that evolved into birds. This one is more related
Speaker 1: to Triceratops, which is the big four legged dinosaur with
Speaker 1: the three horns, and this means feathers were even older
Speaker 1: than people.
Speaker 3: Thought by finding feathers in a more primitive dinosaur. If
Speaker 3: these two groups of dinosaurs had them, well, that kind
Speaker 3: of implies that the genetic machinery for making feathers may
Speaker 3: have actually evolved very early during dinosaur evolution, so that
Speaker 3: these distantly related types of dinosaurs had the ability to
Speaker 3: produce feathers.
Speaker 1: What doctor McNamara is saying is that the fact two
Speaker 1: distant dinosaur cousins had feathers implies that their ancestor also
Speaker 1: had feathers. It's sort of like if you and your
Speaker 1: cousin have the same gene, the gene probably didn't start
Speaker 1: with you. You both probably got it from your common
Speaker 1: grandmother or grandfather. This meant that feathers didn't start with
Speaker 1: the dinosaurs that became birds. They go back even further.
Speaker 3: There is also the option that maybe two groups of
Speaker 3: dinosaurs evolved feathers independently, but we actually considered it much
Speaker 3: more likely that this shared possession of feathers reflects common ancestry,
Speaker 3: that they were present in the common ancestor. So that
Speaker 3: was the stage of play for about six or seven years.
Speaker 1: That's right. That story only lasted about six years. And
Speaker 1: that's because in twenty nineteen, doctor McNamara and her colleagues
Speaker 1: found another fossil that totally threw that story out the window.
Speaker 1: When we come back, we'll talk about that discovery and
Speaker 1: we'll hear from our experts why scientists thinks evolved. Stay
Speaker 1: with us, you're listening to science stuff. Welcome back, all right.
Speaker 1: We're telling the story of what we know about dinosaurs
Speaker 1: and feathers. In twenty thirteen, palontologist doctor Maria McNamara was
Speaker 1: part of a team that made a remarkable discovery. The
Speaker 1: fund feathers is a distant cousin of the dinosaurs that
Speaker 1: eventually evolved into birds. And this meant that feathers didn't
Speaker 1: evolve with birds, nor did they evolve with the dinosaurs
Speaker 1: that became birds. Other dinosaurs had them, which meant the
Speaker 1: origin of feathers went back even further. But how far back,
Speaker 1: which dinosaur ancestor was it that first evolved feathers. The answer,
Speaker 1: it turned out, was even more surprising than anyone expected.
Speaker 3: That was the stage of play for about six seven years,
Speaker 3: and then in twenty nineteen we discovered feathers in a
Speaker 3: completely different group of animal. We discovered feathers in pterosaurs.
Speaker 1: That's right, Doctor McNamara and her colleagues found feathers in
Speaker 1: animals that aren't even dinosaurs. They found feathers in pterosaurs. Now,
Speaker 1: what are pterosaurs.
Speaker 3: These are the giant flying reptiles, the cousins of dinosaurs
Speaker 3: that roamed the skies during much of the Mesozoic. So
Speaker 3: we found these little baby pterosaurs, these two juveniles from
Speaker 3: China that literally had feathers covering their entire bodies, and
Speaker 3: they had four different types of feathers. They had some
Speaker 3: simple hair like feathers that we have found on lots
Speaker 3: of dinosaurs and that are also present in modern birds,
Speaker 3: and three types of branched feather feathers that branch at
Speaker 3: the base, feathers that branch and shaffway along the shaft,
Speaker 3: and even some feathers that branch at the tip. So
Speaker 3: we find these in these juvenile terosaurs.
Speaker 1: So they found feathers, real feathers in animals that are
Speaker 1: not dinosaurs. They're more like the cousins the whole group
Speaker 1: of dinosaurs. Now what does this mean, Well, there are
Speaker 1: two possibilities. Either pterosaurs, the flying cousins of dinosaurs, also
Speaker 1: evolved feathers, and the feathers look the same by sheer coincidents,
Speaker 1: or feathers evolved way in the past before these two
Speaker 1: groups of animals branched off. Now, the first possibility that
Speaker 1: both groups of animals involved feathers and they look the
Speaker 1: same by sheer coincidents does sometimes happen in nature. It's
Speaker 1: called convergent evolution. For example, birds evolved wings, but so
Speaker 1: that bats and sharks evolved fins and a streamlined body,
Speaker 1: but so that whales. But in the case of feathers,
Speaker 1: paleontologists argue this is very unlike likely. Here's how doctor
Speaker 1: Jingme O'Connor explains it.
Speaker 2: The one of the ways that paleontology makes hypotheses is
Speaker 2: based on the principle of parsimony.
Speaker 1: Okay, parsimony in general means being economical or cheap, but
Speaker 1: in the context of science, it means that if you
Speaker 1: have two possibilities, usually the one that's right is the
Speaker 1: simpler one. If you've heard of Alkham's razor, it's pretty
Speaker 1: much the same thing.
Speaker 2: It's basically assuming that instead of evolution evolving these feathers
Speaker 2: in pterosaurs and then also evolving them a different time
Speaker 2: in dinosaurs. Since these groups are so closely related, it
Speaker 2: would be most parsimonious that the common ancestor of these
Speaker 2: two groups already had these features. And the reason it's
Speaker 2: present in pterosaurs and dinosaurs is because they both inherited it.
Speaker 1: What doctor O'Connor is saying is that it would be
Speaker 1: a stretch for both dinosaurs and pterosaurs to evolve feathers
Speaker 1: independently out of the blue, especially because a the two
Speaker 1: groups of animals are closely related, so it's not a
Speaker 1: stretch to imagine their common ancestor had feathers, and b
Speaker 1: Feathers are complex, They're not easy to just suddenly evolve.
Speaker 2: Feathers are complex structures, complex poratinous outgrowths. So the more
Speaker 2: complex the structure is, like, the more unlikely it is
Speaker 2: to evolve, you know, rather than having these complex like
Speaker 2: caoratinous external structures evolving a bunch of different times and
Speaker 2: all these dinosaurs and also in pterosaurs, it makes more sense,
Speaker 2: or it's more parsimonious for it to evolve once in
Speaker 2: the common ancestor.
Speaker 1: And if you assume feathers evolved in a distant ancestor
Speaker 1: of dinosaurs and pterosaurs, it means that feathers evolved before
Speaker 1: dinosaurs existed.
Speaker 3: We favor the idea that the presence of feather is
Speaker 3: in terosaurs and dinosaurs. We feel that this implies that
Speaker 3: the genetic networks required to grow feathers must have evolved
Speaker 3: in the common ancestor of pterosaurs and dinosaurs, and that
Speaker 3: common ancestor we predicted would have lived seventeen million years
Speaker 3: earlier than both.
Speaker 1: And this leads to the shocking answer I promised. If
Speaker 1: feathers evolved before dinosaurs became their own branch of animals,
Speaker 1: it means the ancestor of all dinosaurs had feathers, which
Speaker 1: means all dinosaurs had feathers. It's not that a few
Speaker 1: dinosaurs and feathers, or that some dinosaurs had them. They
Speaker 1: all had feathers, or at least they all had the
Speaker 1: genes the ability to grow feathers. We'll get to what
Speaker 1: that means in a minute, but first it turns out
Speaker 1: that's not the end of the story.
Speaker 3: And that was the accepted state of play for the
Speaker 3: last few years and most of the community. You know,
Speaker 3: we're happy with the evidence that we put forward that
Speaker 3: these structures were feathers, because we had evidence from microscopic analyzes.
Speaker 3: We had evidence from chemical analyzes that they basically contained
Speaker 3: the same sorts of pigment granules as feathers, and they
Speaker 3: contained you know that we had chemical evidence for the
Speaker 3: kerot and protein. But this year we produced really a
Speaker 3: quite shocking discovery.
Speaker 1: What another shocking discovery.
Speaker 3: We were looking in some early Triassic rocks. We were
Speaker 3: looking at animals that really they are very distant relatives
Speaker 3: of dinosaurs and pterosaurs, and we found that some of
Speaker 3: these very early Triassic reptiles, they preserve this remarkable structure
Speaker 3: on their back that's made of these materials which look
Speaker 3: so similar to feathers. They contained the same pigment granules
Speaker 3: as feathers, but they lacked branching, so they don't fit
Speaker 3: our kind of conventional idea of what a feather is,
Speaker 3: So to be very conservative, we probably shouldn't call them feathers.
Speaker 3: They do tell us that there were animals living in
Speaker 3: the early Triassic that had structures that might have had
Speaker 3: many of the same functions as feathers.
Speaker 1: So just this year, in twenty twenty five, doctor McNamara
Speaker 1: and her colleagues discovered proto feathers or prefeathers in an
Speaker 1: animal that lived way before dinosaurs, which means it wasn't
Speaker 1: just the ancestor of dinosaurs that had feathers, go even
Speaker 1: further back. How far back scientists don't know. So here's
Speaker 1: the working hypothesis. Feathers, or the genetic mutation that allows
Speaker 1: an animal to grow these complex proteins into a structure
Speaker 1: on their skin, evolved long before dinosaurs, and we see
Speaker 1: feathers today in birds which descended from dinosaurs, which means
Speaker 1: all dinosaurs probably had those genes. But does that mean
Speaker 1: that t Rex or every dinosaur basically looked like a
Speaker 1: giant chicken. Not really. Palatologists think all dinosaurs had the
Speaker 1: capacity to grow feathers, but some didn't use it red
Speaker 1: least once they got big, they didn't need it, which
Speaker 1: brings us to the reason feathers might have evolved in
Speaker 1: the first place, staying worn.
Speaker 2: So it's very likely that large dinosaurs, if not completely
Speaker 2: lost their feathering, like highly reduced it. And so that's
Speaker 2: why I brought up the analogy with the elephant. I mean,
Speaker 2: elephant is like a big mammal, so it has to
Speaker 2: get rid of body heat. It also lives in a
Speaker 2: really hot place, but it hasn't completely lost its fur.
Speaker 1: It still has it.
Speaker 2: It's just very sparse. So that's why I'm just making
Speaker 2: the argument that maybe big dinosaurs would have highly reduced
Speaker 2: their feathering, but would they completely lose it?
Speaker 1: I don't know.
Speaker 2: Like, I can't think of any mammal that has completely
Speaker 2: lost its hair except for aquatic ones. I don't know
Speaker 2: if like we have had some hair somewhere, whales or hair,
Speaker 2: that'd be so funny.
Speaker 1: I guess maybe a question is, what's the evolution of
Speaker 1: those from proto feathers to the feathers we see, like
Speaker 1: the beautiful feathers we see birds today. What was that progression?
Speaker 2: So I just want to give a disclaimer that the
Speaker 2: progression from proto feather to complex fractal feather, which we
Speaker 2: call prenaceous feathers, it's highly hypothetical.
Speaker 1: Gosh, we could spend a whole other episode just in this,
Speaker 1: but here is the working hypothesis. Feathers likely evolved to
Speaker 1: keep small animals warm, sort of like fur. You can
Speaker 1: find this in animals dating bag to be four dinosaurs.
Speaker 1: But then two things happened. Some dinosaurs started getting big,
Speaker 1: and so they stopped needing this coat to stay warm,
Speaker 1: which is why you only see baby pterosaurs covered in
Speaker 1: feathers and why paleontologists think maybe baby t rexes had feathers,
Speaker 1: but big adult ones didn't. They probably shed a lot
Speaker 1: of it off, so no giant t rex chickens probably
Speaker 1: And also evolution figured out feathers were also good for
Speaker 1: other things.
Speaker 2: So exactation is the fancy evolutionary biology word for evolution
Speaker 2: taking a feature that has evolved for some other reason
Speaker 2: and then hijacking it for another function. So sinoserapter its
Speaker 2: fuzzy little dinosaur covered in proto feathers, but tail is striped.
Speaker 2: These feathers are not just being used for thermal regulation.
Speaker 2: They're also being co opted for communication, either within a
Speaker 2: species like hey you know wag my tail. Hey you're
Speaker 2: also sinoserapteris what's up? Or Hey, this is my territory,
Speaker 2: go away, you know, like just some kind of display,
Speaker 2: some kind of communication. We really can't say.
Speaker 1: So that's why you see some dinosaurs with the fancy
Speaker 1: complex feathers. They used it for mating or to intimidate
Speaker 1: other dinosaurs, and then eventually the di dinosaurs that would
Speaker 1: evolve in the words figured out, hey, these feathers are
Speaker 1: also pretty good for flying.
Speaker 2: So for example, feathers like the fancy, panacious feathers, they
Speaker 2: evolve for some other purpose and we're exacted for flight.
Speaker 1: Like I said, we could go on a whole tangent
Speaker 1: about feathers. But to recap the main question of the episode,
Speaker 1: did dinosaurs have feathers? The answer is yes, they all did,
Speaker 1: and this is something we just recently found out. Does
Speaker 1: that mean all dinosaurs looked like giant chickens? Not necessarily,
Speaker 1: but it definitely means they're a lot fuzzier than we
Speaker 1: thought before. All Right, close the episode, here's doctor McNamara.
Speaker 3: So that's where we are. It opens up all sorts
Speaker 3: of ideas about where did feathers evolve? You know, are
Speaker 3: we going to find true feathers in the early Triassic?
Speaker 3: If that's the question we're asking, Well, these new fossils
Speaker 3: from the Triassic tell us that in order to find
Speaker 3: the answers for feather origins, we need to look back
Speaker 3: in even all the rocks before the Triassic, And to
Speaker 3: be honest, that's somewhere where we never thought we were
Speaker 3: going to have to go.
Speaker 1: That is amazing. Last question I guess is what gets
Speaker 1: you excited about finding the origin of feathers.
Speaker 3: Because they are just one of the most complex tissue
Speaker 3: structures that vertebrates have, and because there's so much kind
Speaker 3: of required to produce them. I just really want to
Speaker 3: know why did vertebrates start producing these, Why did they
Speaker 3: give us an advantage? Why did they give our deep
Speaker 3: deep ancestors an advantage. I'm just really intrigued by it.
Speaker 3: What really was driving evolution once we come on to land,
Speaker 3: What do we do in this new environment? What are
Speaker 3: the major challenges? You know, these are just really big
Speaker 3: evolutionary questions, and we have the opportunity with feathers actually
Speaker 3: to address some of that. So I just think it's
Speaker 3: really fun.
Speaker 1: That's so wonderful. Well, I hope you do get a
Speaker 1: Nobel Prize for the Professor McNamara, or at the very least,
Speaker 1: I hope you get a feather in your cap.
Speaker 3: Thank you, Thank you very much.
Speaker 1: All right, Hey, be sure to check out my latest book,
Speaker 1: Oliver's Great Big Universe Evolution Changes Everything. Look for it
Speaker 1: in your favorite online or local bookstore, or go to
Speaker 1: Great Big Universe dot Net to learn more. Thanks a lot,
Speaker 1: See you next time you've been Listening to Science Stuff
Speaker 1: production of iHeartRadio Britten and produced by me Or Hitcham,
Speaker 1: edited by Rose Seguda, executive producer Jerry Rowland, and audio
Speaker 1: engineer and mixer Kasey Peckram. You can follow me on
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Speaker 1: get your podcasts, and please tell your friends we'll be
Speaker 1: back next Wednesday with another episode. Hey, if you're wondering
Speaker 1: how feathers can survive the fossilization process, here's our first
Speaker 1: ever appendix with doctor Magnamara's explanation. How do these feathers
Speaker 1: get preserved as fossils? I thought only like bones got
Speaker 1: preserved as fossils.
Speaker 3: So yeah, ninety nine times out of one hundred, you're right.
Speaker 3: And usually when animals die, bones are the only things
Speaker 3: that end up getting preserved. But sometimes the soft tissues
Speaker 3: of animals and plants they don't rot away completely. In
Speaker 3: the case of feathers, they're made of those proteins. They're
Speaker 3: pretty tough, they're pretty robust, and they actually undergo transformations
Speaker 3: when the rocks are buried and the molecules start to
Speaker 3: link together. They form large polymers, and it turns out
Speaker 3: that it's really hard for bacteria to destroy those polymers,
Speaker 3: so once they start to polymerize, it actually enhances their
Speaker 3: preservation potential.
Speaker 1: So some of these proteins actually survived the fossilization products
Speaker 1: like you can see them in the rock.
Speaker 3: We can actually track the three dimensional architecture of the protein.
Speaker 3: That's what's really distinctive about feather proteins is that three
Speaker 3: dimensional corrugated shape rather than the helical shape. So we
Speaker 3: know for a fact that some of the earliest birds
Speaker 3: and feather dinosaurs their feathers were made of the same
Speaker 3: proteins as the feathers of modern birds.