Terror Birds

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Apex Predators, that roamed the plains of South America for millions of years, mega carnivores, that followed the dinosaurs. Flightsless, yet monstrous. Scientifically, they are known as forest rackets. We know them simply as terributs.

So what do we know about these monster birds? What do we know about this prehistoric age where they thrived when South America was an island isolated from the rest of the world?

“And what ultimately led to their downfall to their extinction?”

Welcome to the ancients, I'm Tristan Hughes your host and this is the story of the terributs. Our guest is Dr. Steve Brassati, personal chair of paleontology and evolution at Edinburgh University and the author of the story of birds. Steve, it is so good to have you back on the show.

Tristan is always a pleasure, I've always loved talking to you guys and bridging the science

and history worlds and talking about the deep prehistory that I study as a paleontologist. We love doing prehistoric animal episodes once in a while, whether it's the dinosaurs or from this period right after the dinosaurs. Maybe not right after, but few many years after. And as we'll see, it still kind of was the age of dinosaur because birds are dinosaurs

we can get to that of course. And these are the terributs, right?

“They seem in sound so bizarre to have ever existed, but they did.”

They did, they did and this is really the lesson of the fossil record that sometimes we find fossils of things that don't live anymore. We would have no idea they ever existed, but we have the fossils and the fossils are totally bizarre, totally wacky, sublime. The terributs are a great example of that.

These were birds that would have been terrified, the nicknames suits them. They were top predator birds, they were basically birds that gave up the ability to fly. They traded flight in order to get bigger in order to grow to large sizes. They were bigger than us, not all of them, but many of them were. And they were the top predators in South America for tens of millions of years.

Not just many of you. It's tens of millions of years. And I probably butchered the naming of it, the pronunciation of its scientific name in the intro. How do we say it?

Oh, yes. Oh my god. That was the one thing I was hoping you wouldn't pass. I don't know. So it's a name that goes way back, the Amigino brothers in Argentina.

These were basically the family, there are three brothers. They were the founders of paleontology as a science. In Argentina, they were immigrants, their family came from Italy and they established themselves in Argentina. One of them ran a bookshop, one of them did expeditions and explored and collected fossils

and one of them wrote scientific papers about the fossils. And they came up with this name based on this little jaw. It was just a few inches long. At first, they didn't really know what it was. Now this was way back in the 1800s, okay, so this was long before we knew a lot about

the different types of dinosaurs and they were two tigers and willy mammoths and all of these

amazing fossils that we now know about.

And so they found this thing. It looked like a jaw. It had no teeth in it, but they thought it was a mammal jaw that had just lost the teeth. The teeth had fallen out when it was fossilized. And they thought it could have been something kind of like an antider or a sloth or an armadillo,

something like that, which makes sense because these kind of animals mammals live in South America.

Yeah, I didn't have teeth. The reason it didn't have teeth was because it was a beak and it came from a bird. Now, as you'll see, I'm stalling. So I don't have to pronounce the name.

I don't actually, I must say, I've never actually been sure of the correct pronunciation.

It's one of these long words. I think it comes from Greek. I can't remember this. Yeah, so it's for us a rackets or something like that. Yeah, and so Ph.O.R.

But there's a reason why they're called the Terror Birds because they're terrifying, obviously. It's a great nickname. But the nickname is really stuck because the scientific name is such a tongue twister that is so hard to pronounce. Then we will stay with Terror Birds.

We will stay with Terror Birds. I should have had better prepared for you. No, you. This is why, so, you know, the book, you mentioned the story of birds. I think it's behind me.

I have all chapter on these, these things.

“And that's what I love about writing is that it doesn't matter.”

I don't record the audio book, so I don't have to say some of these words. That's for some other poor souls to do. Well, okay. So the Terror Birds, when are we talking, if there are apex predators for tens of millions of years, which tens of millions of years should we be thinking of?

So as always with the fossil record, we don't exactly know when the very first Terror Birds

live. But we can say that the oldest fossils come from what's called the Easene Time. This is one of the subdivisions of the beginning of the age of mammals, basically the time after most dinosaurs went extinct. So we're talking about probably between 50, 55 million years ago.

We know there were Terror Birds. But those first fossils are really fleeting little glimpses. They are rare clues. There's just not a great fossil record in South America at that time. So it's likely they went back even earlier.

Maybe they originated soon after T-Rex and Triceratops in the classic dinosaurs when extinct. That would have been 66 million years ago.

“But we can be confident, I think, that sometime between about 66 million years ago and”

about 50 million years ago, that's when Terror Birds entered the scene. And they would continue to live, to diversify, to evolve, to adapt for many tens of millions of years more. Last ones, when extinct, really just a few tens of thousands of years ago, just just before the very first humans reached South America.

So we didn't cause their extinction by the way, this is when we're absolved the blame. This was a natural thing. We don't know exactly why, but there were big waves of immigrants from North America. Other types of animals that came down when North America and South America finally docked together.

And it would explore that extinct to that extent. But so we have, let's say roughly 50 million years of Terror Birds, they only lived in South America, except for this one species that did make its way northwards across the isthmus of Panama. May have actually even migrated even a little bit before North and South America touched.

And this one got into Florida, got into Texas, made its way to California, but it didn't last very long. So there was a rare American terror bird. We have other terrors in the United States of America.

This terror bird never quite gained a foothold.

I'm jealous you've got Terror Birds compared to here where we didn't. But that's another story, but you will also make an important point. So the age of the Terror Birds, the real time when they are really at the top. This is a time when South America is an island. That is exactly right.

So think about Australia today. It's a continent. It's a big slab of land, but it's an island. It's not connected to anything else. South America was like that for many tens of millions of years, 60 million years, maybe

even 80 or 90 million years. So it used to be part of what was called Gondwana. That was the southern half of Panjia, which was the single supercontinent. So Panjia was around for a long time. Then it basically split from east to west and from north to south.

South America was in the south. It remained connected to Africa for a long time.

“That's why they looked like puzzle pieces if it together because they did for a long”

time. Australia was part of that Gondwana continent. So it was Antarctica. So it was Madagascar. So it was India.

India used to be part of the south. It's only very recently moved northwards. Then that Gondwana continent, it broke apart. And somewhere between probably 70 and 90 million years ago South America went off on its own.

A large chunk of land, a continent in a zone right, but an island divorced from everywhere else. Because it was isolated, the animals there, the plants there, they evolved and splendid isolation as the biologists like to say. So you get all kinds of wacky creatures living there that are pretty much disconnected from

the bloodlines on other continents. And it remained that way until South America and North America made their connection. So we set the scene.

So now let's explore kind of getting to Teribards in the story of that evolution story. So interesting. And I feel we should probably start with the extinction of the dinosaurs.

So 66 million years ago, what happens?

Oh, I thought we were a stay in the history of the earth happened. I know, I mean, that actually.

“I mean, it sounds hyperbolic, but I think it really is true.”

Because 66 million years ago, one random day, this rock fell out of the sky. This was an asteroid. It was about six miles or about 10 kilometers wide. So basically, a rock, the size of Mount Everest or a rock, the size of the city of Edinburgh where I live.

So you look at Edinburgh on the map, that's basically the size of this rock. It was hurtling through the emptiness of outer space. So it was basically a leftover crumb from the formation of our solar system, a piece of space junk. And it could have gone anywhere, but it just so happened to make a B-line for the earth.

And it smashed into what's now the Gulf of Mexico. Very close to Cancun, the very popular tourist town on the Eucutam Peninsula. And it exploded.

It detonated with a force that was bigger than a billion nuclear bombs put together.

So just unimaginable fury. I mean, it punched a hole in the face of the earth more than 100 miles wide. And that crater today is mostly covered by the water of the Gulf of Mexico. But you can still see some traces of it on land. So this was catastrophic.

“This was the biggest asteroid to hit the earth in at least the last half of billion years.”

And it triggered earthquakes and wildfires and volcanoes. And all the dust and the dirt and the grime from that collision, the soot from the fires went up into the atmosphere. The atmosphere has currents, like the ocean does. So that stuff spread around the world.

And before long, the earth was plunged into darkness. It was a global nuclear winter. The earth went dark and cold. Maybe for a few years, maybe for up to a decade or so. And that was the real agent of doom, 75% of species went extinct.

If you were alive the day the asteroid hit your entire species, a one and four chance to survive. Really? And it's in those following years, months and years that the extinction has really happened because of entering that nuclear winter time period. That's right.

I mean, I don't really want to imagine it because I'm so grim. But I mean, imagine if the earth, the entire earth basically was dark and cold. There was no sunlight or very little sunlight that could get through plants could not photosynthesize. They couldn't make their own food.

“So those ecosystems on land, where there were forests and jungles, they would collapse.”

And so the plants would die. The plant heaters would die. The meters would die. You know, these ecosystems would collapse like a house of cards. Same in the ocean.

The ecosystems in the ocean are based on what are called phytoplankton, these little microscopic creatures that also make their own food using sunlight like plants do. So food webs just collapse. There was very little food to go around. If you were a big animal, you were in trouble.

There just wasn't much food to eat. And if you couldn't hide very easily, if you couldn't dig a burrow, if you couldn't move away from the danger very quickly, you'd be in trouble as well, especially when there were the fires and the earthquakes and the tsunamis. And if you grew slowly, you'd be in trouble.

Imagine if it took you many months to lay eggs and raise your babies. And if as a baby it took you many years to become an adult. I mean, that would not be a good strategy for getting through this sort of destruction. So it's those types of animals that really die. That's probably why most of the dinosaurs die.

T-Rax triceratops, the long neck ones, they were big. They needed to eat a lot of food. They couldn't hide very easily. They didn't grow very quickly.

So they had dominated the world for 150 million years.

Now suddenly things had changed so quickly, so profoundly that they were on the back foot. And they didn't make it through but some animals did. Oh yes, who are the great survivors? Who are the great survivors? Great.

So there were many victims. The big dinosaurs were among them, the tarot actals, those reptiles that were flying around over the heads of dinosaurs, not quite true dinosaurs cousins, but they died as well. All of those reptiles living in the oceans. The Mozesaurus.

The Mozesaurus. The pleziasaurus. They died as well. The Ammonites, those beautiful fossils, they're so common here in Britain. Those coiled shells.

You know, there's so many of us collect daydide, but some things did survive or else we wouldn't have life today. And one of the survivors was this group of small furry little creatures that could eat lots of different types of food but didn't need to eat huge volume to food because they were small.

They could dig burrows. They keep themselves warm with their hair. They could raise their babies really quickly, turn over the generations quickly. Those animals were mammals.

So we had ancestors that stared down the asteroid.

“And again, if we didn't, we wouldn't be here.”

You know, our whole evolutionary family had to get through that bottleneck. But there were other survivors too. And some of them were also small, but they didn't have hair, bad feathers. And they could fly with those feathers so they could move around quickly. They didn't need to eat a whole lot of food.

They grew super quickly. And they had beaks, which means they could eat seeds. And when forest collapse and ecosystems collapse, we see this today. If there's a volcano that obliterates an island or a big forest fire, seeds will remain. Really?

Seeds will really be the last thing that remains. So if you could eat seeds, it wouldn't keep you alive forever. But you would at least be able to eat the last surviving food. You could stick around for a while. Now, these animals of course were birds.

And so it was probably because that hand of cards.

That was the winning hand of cards being small, growing fast, being able to fly, being able to eat seeds. Those were the things that helped them stare down that asteroid alongside our mammal ancestors. So these small birds will focus on the birds.

Oh, see, mammals are there as well. Oh, yeah, we do mammals in other areas.

“Another day, I think we have done it, well.”

But these small birds, they survive the nuclear winter. And so they emerge as into this brave, new world. I mean, how do they then get very big? How do we then get to things like the teribards from really small survivors?

Well, imagine what it would have been like to be one of these animals that did survive, that you endure this nuclear winter for a few years or a decade or so. And then the sunlight starts to trickle through the cloud. It must be quite something.

It would be, Yuri, you'd look out on this devastated world, this desecrated planet. But this was also a course to a world of opportunity. T-rex is gone, triceratops is gone. Those enormous, long neck dinosaurs

that would crush you with the single footfall, they were gone. So if you could survive, you now had the opportunity. And evolution, of course, doesn't like a vacuum. And it will fill that vacuum. If there's opportunity, evolution, my natural selection

will shape organisms to take advantage of those opportunities. So what we see is both birds and mammals start to proliferate. From those few survivors, you get lots of new species really quickly. And you start to see some of those species. Yeah, they stay small and they stay doing what their ancestors did.

But some of them start to do new things. They get bigger. They move to new places. They start to eat different foods. And they start to form these more complex ecosystems.

So we're now, there's a lot of mammals and a lot of birds in many different roles in the food web. And that is how we say the age of mammals started. But really, this whole age of mammals thing. We say it because we're a mammal.

But look, there's over 10,000 species of birds today. That's about double the number of mammal species. So in many ways, we should be talking about us being in the age of birds now. Or maybe even the age of dinosaurs, if we want to be really cute about it. So how do we get from-- so there's a lot of then diversifying

of birds in that brave new world. Do we know much about the particular family line, the particular lineage

“that's went to South America and started getting bigger and bigger?”

We know some things. We know that the birds that survived. We have fossils of some of these birds that are there right at the end of the crutaceous right before the asteroid. And some of these birds that survived were ones that were pretty small.

They live not in the trees, but they lived on the land. They were ground birds or water birds. And by that, I don't mean something like a penguin, but something more like a duck. And in fact, some of these birds were actually in the duck group on the family tree. For a historic duck.

We historic ducks living with T-Rex, walking around, quackin' around, and going T-Rex. So I'm just imagine you don't know what's up now. We're next to T-Rex. Oh, yeah, there you go.

There you go. And so these were the birds that did survive. And then afterwards, they were the ones that had that opportunity to proliferate. We don't have enough fossils to know every detail of that story. And this is true, especially of birds because birds tend to be small.

Their bones are really, really light. In fact, most bird bones are hollow. They're full of air. That helps birds be lighter so they can fly better. So it's hard to preserve something small, something delicate as a fossil.

We do have fossils. It's just that we don't have loads of them. And a lot of times, we need those really special opportunities where a whole bunch of fossils are preserved in the same place because of some weird contingency of prehistory

where some volcano erupts and berries a bunch of stuff like Pompeii, that happens with fossils, or there's some lake where a bunch of stuff falls in. And it's just the right chemistry to preserve the bones.

So we're always at the mercy of the fossil record.

So what that means is we don't know exactly

We know from the bones of terabirds

“that they are very similar to birds that still live in South America today.”

And these are the seriamas. Now, they look nothing like a terabird. They're smaller, but they live in the ground. They don't fly a whole lot, or at least they don't fly, you know, they're not ace flyers like some other birds.

And they can be quite ferocious. So we know that these seriamabirds must have got to South America at some point not too long after the extinction. I should say we can build family trees of modern birds

using DNA, you know, DNA. You use it like a paternity test. You can build family trees of animals using their DNA. And we can tell that a huge amount of the diversity of modern birds was established soon after the dinosaur extinction,

soon after the asteroid. There was this manic blitz of evolution.

And so it seems like probably within the first few million years

at most. And these seriamabirds and their close relatives would have diverged from the other birds that are rapidly evolving. And then somehow they got to South America. And then when they were there, some of them

“then gave up flying, traded flying for being able to get bigger.”

It's really an evolutionary trade-off because it's very hard to fly if you're big. I mean, it's one thing if you're an airplane. I mean, you have your fixed wings and big engines on it. But if you're an animal like a bird that has to flap wings

and power those wings with muscles, really, once you get past a certain size, it's just not going to really work. So to be something as hefty as a terror bird, something that weighed hundreds of kilos,

you couldn't really fly very easily with that kind of body weight. So these ancestors gave up flying, got bigger, basically supersized their bodies, became real true big birds.

And moved into the top predator niche in ecosystem.

Wow. And we're now going to delve into the anatomy of a terror bird. Right after this. Boo! You've got some advice? I have your mobile phone number.

Your whole mobile phone number is higher! [LAUGHTER] I have no idea. Not my mobile phone number. Phew.

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[MUSIC PLAYING] So Steve, that's the story of how we get to terributs in both getting very big in South America. And I learned at that time, giving up flight to get big.

“The biggest birds to have ever lived, is that fair to say?”

They weren't quite the biggest birds. They were among them, but there are some other weird fossil birds that are even bigger. There were things that once lived in Madagascar that were called elephant birds, things can see.

These things get great nicknames. And they weighed well over a thousand pounds. They were something like the 700 kilo range. They laid eggs the size of watermelons. Wow, OK.

They were the biggest birds. And there were some in Australia called demon docks. Demon docks. Which weren't quite as tall as an elephant. For elephant birds, got to be like 10 feet tall.

Demon docks were a bit shorter, but they were heftier. Now both elephant birds and demon docks, though, were plant heaters. So we call them demon docks, but they weren't really that demonic. Right.

The biggest-- They were the big birds. The biggest bird predator. The biggest bird predator. That's very good.

OK, that's my-- that's my question. Thank you very much. But yeah, let's explore the body structure, what we know from the surviving fossil. So let's start with the head.

So they trade flight for incredible height and size.

I'm guessing the skulls are pretty-- extraordinary, pretty ferocious. The skulls are insane. And we were just looking at not a real skull, but a cast copy of a skull in the National Museum of Scotland,

the other day. I was just looking at it with my students. And this thing is about this big. I mean, it's basically the size of a horse's head. Wow.

And at the end of it, of course, there's a beak. These things didn't have teeth. They didn't have steak knife teeth, like T-Rex or Velociraptor. They couldn't, you know, birds don't have teeth. They've lost the ability to grow teeth.

but then very quickly, they replace by the beak.

“So what that means is if you want to be a bird and you”

want to be a predator, you've got to use your beak to do it, you can't just use teeth. And so these terabirds had ferocious beaks. Their beaks were hooked. Big nasty hook, kind of like, you know,

eagle or a hawk or something like that, but a much bigger, much sharper, much nasty or weapon at the end of the beak in terms of that hook. And then the size of the beak are very, very sharp. And the skull as a whole is quite big.

It's very robust. Most birds today have lots of bones in their heads that are linked together very tenuously by ligaments and by muscles. So birds have a lot of movement, different than us.

We have kind of this bit of our head, and our jaw, and that's it.

The bones have fused together, but not most birds.

Terabirds have kind of done what we've done. They've fused up a lot of those bones. So they could make their skull extra strong. So they could bite harder with their muscles. It's sort of about the bite.

It's all about the bite. And there have been some scientists,

“people like Dino de Grande, Larry Whitmer, my colleagues,”

they study anatomy. They study what it's called biomechanics, how animals move and feed, and what they do. And they run these different tests, mostly using software. It's type of software that engineers use

to build when they're building a bridge, or building a skyscraper, you don't want to just start building. You want to model it. You want to make sure the thing's going to be strong enough. And so they're software that does this.

And these paleontologists, they've used the software. And they've shown that these terabirds had really strong bites, and that their skulls were really robust in order to accommodate that bite. So the skull didn't break apart in order to give us

a proper scaffold for the muscles. And probably-- and this is based on these computational analyses, these modeling analyses-- they think that terabirds use their head to basically batter their prey.

They would go down and strike. - Repetitively. - Repetitively, yeah. Repetitively, I mean, not like a crazy ax murder or something, just going nuts, but strategically. And they also had other weapons.

They had really powerful legs, really thick legs,

really big claws at the end of their feet. And it looks like those legs had a wide range of motion, and they could be used to kick, and they could be used to also pummel prey. So it seems like they might have best weekend

health from the fossils, use their feet to get a little mammal or a big mammal or whatever, into submission, and then attack with the beak pummel it. - I mean, yes, before we kind of go down the body, I mean, what prey should we be thinking of?

“So small and medium-sized mammals, what types do we think?”

- Yeah, so South America, during this time, when it was isolated as an island continent, it did not have all the same mammals as most of the rest of the world. A lot of the mammals there were marsupial mammals,

like in Australia today, the ones that give birth to tiny little babies that they raise in pouches. So in Australia, that's kangaroos and wilde bees and koalas. South America also still has a lot of marsupials, and it seems like they got there before South America

was an island, and they just so happened and then have this opportunity to diversify when it became an island. There were some placental mammals. Those are the ones like us that can give live birth

to well developed young. There were a bunch of hoofed mammals in South America. But these were weird hoofed mammals. They were actually studied by Darwin. When Darwin sailed on the Beagle,

he went many times, the Beagle dropped anchor. He would go inland. He would of course look at the plants and the animals and theorize about what they were doing while either in such great diversity,

but he would also try to find fossils. And he would try to understand the history of these places. And so he went inland with some indigenous South Americans and they showed him these giant bones of mammals. Mammals, it seemed like a little bit like a horse,

a little bit like an elephant, a little bit like a rodent. They didn't really match any of the mammals in Europe or in North America. It turns out we now know because some DNA is preserved in some of the bones of those mammals in South America.

They are weird, horse, and rhino relatives. - Okay. - So they would have been like the biggest plant heaters at the time. They were ungulates, yep, they were ungulates, and they were odd-toed ungulates, like a horse, rhinos, and tapers.

They would have been probably some of the primary prey of the terror birds, and they ranged in size, based of the same way hoof mammals do today, from little ones like little species, a deer, and sheep, all the way up to rhinos and cattle and so on.

And then there would have been crocodiles there. There would have been some rodents and some monkeys, which are placental mammals like us, that actually rafed it over from Africa. Their closest relatives are African.

- Wow. - So they must have survived these one in a trillion seaword voyages

So that's the world that terror birds lived in.

“This isolated island fortress of South America.”

They were the top predators. These strange hoof mammals were the biggest plant heaters. They were also a lot of marsupial mammals, and there were crocodiles, and there were some weird rodents and monkeys

that had come from Africa. This was that world, very different from anywhere else. That was the world that terror birds ruled. - Well, let's keep going down the body. So we've mentioned the massive head

and they're incredibly powerful beak

and attacking the prey. But when you get images of terror birds, their neck is incredibly long, almost giraffe-like. So what do we know about the neck? - It's cool, isn't it?

I mean, there's so many things when you look at a terror bird, when you look at the skeleton, that is just like, that's weird, that's wild, that's cool. And some of it are those extreme things

like that big hooked beak, or like the really powerful feet, or the tiny little wings. It didn't need wings to fly, but it kept them. Probably the same reason and ostrich keeps them today,

to use for display, to attract mades and intimidate rivals, and maybe to help turn and break and slow down and you know when they're running. Those things are weird. Other things about terror birds, though,

are actually quite normal for birds. Just when you see them at giant size, they look strange. And the neck is one of those things. Birds have quite elongate, quite gray-style, gracefully curved necks.

And if you look at the skeleton of a pigeon, or a chicken, you'd see the same thing. And that's actually something they inherited from their Velociraptor type dinosaur ancestors. So that gracefully curved neck with the head at the end,

“that's what allows birds to move their heads,”

you see birds moving their heads, bobbing their heads all the time, that's a normal bird thing. But when you look at a terror bird, it's so big, the neck looks so stretched. It kind of does look a little bit like a birdy version

of a giraffe. And that adds, I think, to the charm, and to the quirk of this animal. - Yeah, they must be incredibly mushy necks, as well, you know, it's kind of all the movement.

And then the body itself is its small wings, completely covered in feathers. And I am picturing almost like an ostrich today, that kind of ovalish kind of body. - I think it would look quite similar to an ostrich.

Of course, the head would be much different. I think it's pretty small heads. Terror birds would have these enormous heads. Terror birds probably had all things considered smaller wings, but it's hard to tell because we don't get

the feathers really preserved as fossils, very commonly. Terror birds would have had bigger, more muscular legs. The ostrichs are super fast. They're the sprinters of, not really the bird world, really the animal world.

“I mean, these things are out in the Savannah, in Africa.”

And they sprint like the fastest mammal sprint. So, Terror birds probably were pretty fast, not quite as fast as ostrichs, just probably because they were bulkier, but they had these more muscular legs,

and these big, powerful kickboxer feet kept

with these nasty, gnarly claws. Almost like the claws of like a Velociraptor. - And do we know how they were able to walk and run with these massive claws? They would have held the claws off the ground,

you know, like a Velociraptor with it. And there's even footprints of Terror birds that show this as well. They kind of look in some ways like a Velociraptor footprint, you know, you can tell the claws were held up,

so they wouldn't be damaged. So, to me, that's incredible, that these feet, I mean, they were like Swiss Army knives. They could do so many things. They could run fast on these feet,

then they could use their feet as murder weapons. And I mean, that's just, it's just wild to think about. Some birds today use their feet to catch prey, some raptor birds, you know, birds of prey do it. But the Terror birds probably really were like kickboxing

with those feet and jumping, leaping onto their prey, subduing it. And then, if my friends, you know, the science has sort of done these biomechanical models of their correct, then, once the prey was down,

then the head perched on that powerful arch neck,

would have jabbed and jabbed and jabbed. But we think more like Muhammad Ali, as a fighter, you know, just taken the opportunity. Put it back a little bit, you know. - Put it like a butterfly.

- Put like a butterfly. - Sting like me. So float like hummingbird, sting like a terror. I don't know, but, but that's the idea they put forward that it would have been like a Muhammad Ali prize fighter. Not quite like a George Foreman or a Mike Tyson,

but it was much more like boom boom boom boom. More selective, more selective. - Okay, I like you bring it in with those courses. - And I wish I could say I came up with that analogy myself. But in the story, birds, I use that analogy.

I credit Larry Whitmer, my good friend, the paleontologist who came up with it. - I mean, that's been a lovely description. I should write you a lesson. There's no tail or anything like that.

- No, so birds don't have tail. So the first birds did have tails. The first birds in the fossil record would go back to about 150 million years old back to the Jurassic period.

but they also had teeth, they had big claws on their hands

and they had long tails.

“They really looked like little raptor dinosaurs,”

like a little velociraptor than over time, as birds became better flyers. Their wings got bigger, their tails got shorter, just for aerodynamic reasons. And birds today have tail feathers.

They have a big fan of feathers, but they don't have a long, bony tail. They have this little stub, this little nubbin. It's called the pygastile. You see it when you roast a chicken or back home

when we roast Thanksgiving turkeys in America. It's this fatty little ball to the end of the body. There's this little nubbin of bone inside. It's called the Parsons Knows in some old cookbooks. 'Cause it kind of looks like this twisted,

you know, nose of like a person in a medieval wood cutting. And it's really fatty, really glandular. It's not very good eating, but that's it. That's the remnant of the tail. So timbre birds, because they were proper birds,

because they evolved from birds that did fly, they had long lost their tail. So they didn't have a long tail.

“They couldn't use a long tail for balance,”

like say a velociraptor or a T-rex could when they ran. So they must have balance themselves in another way. And I don't really know how they did it. And to me, that seems like a mystery. Gosh, brilliant description of terabytes

and the classic image we have of them today. But as we're about to explore after this short break, there's much more to the story than just that initial design. There certainly is. See you in a second.

I've heard your mobile phone number, but not just that, but I don't get it. We'll see you next time. My second time, D. No, I don't want to go back to the horror room. Phew, just a little bit of a dream.

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So Steve, that's the classic image we have of the terror bird.

Big, powerful, razor sharp claws.

You know, really powerful beak, as well, for attacking. But diversifying, this wasn't the only type of terror bird that thrived in South America for tens of millions of years. That's exactly right. And we should think of terror birds, similar to maybe

how we think of cats. There's so many cats in the world today. And yes, they're all predators of some description. But they range from small little cats all the way up through links and so on.

All the way up to Jaguahers and Cheetahs and tires and lions. And so there would have been a similar diversity of terror birds in South America. The biggest ones were absolutely terrifying to the core. They were thought top predators.

They literally were filling those niches left behind by the big, meeting dinosaurs like T-Rex. But there were smaller terror birds as well. They would have been predators, but they wouldn't have been pummeling these hoofed mammals and devouring these

interesting horse relatives and so on. They would be going after smaller prey. Maybe some of the small marsupials, maybe some of the small rodents, the smaller primates. Do we know much, too?

I'm in basking you this about T-Rex when we don't

previously steps, so I always like asking it.

But I appreciate it's more difficult from the surviving

“archeology, paleontology, do you know much about their young?”

I don't think we do. I honestly don't know. So with terror birds, I had to learn a lot about them to write about them. I'm not a specialist on them in the sense that they're--

I've never dug up terror bird fossils myself or study them directly. Am I studying many other types of birds? I'd love to. This is now on my bucket list and go to South America

and work with some of my friends down there and find terror bird fossils. I just loved to be able to find one of these skulls. I don't know if we have eggs. There may be some eggs have been reported.

There are definitely our eggs that are fossilized for some of these other large birds, like the elephant birds and the demon ducks. And so on these demon ducks that I mentioned from Australia, these giant, corpulent, plant-eating birds,

their eggs are actually found in archeological sites in Australia.

were eating demon duck omelants for breakfast. Wow. Sadly, that's probably why the demon ducks went extinct. So we know the eggs of some of these large birds.

“Terror birds, I think, would have been pretty similar.”

We know, of course, a lot about how modern flightless birds raise their young, ostriches, and casser worries, and so on, they're very good parents. They differ in the details of how they do it. Some of them, the fathers raise the eggs, raise the babies,

which I love, as the father of a little six-year-old. I just love the fact that I see some of these father birds with their kids. So we don't know, I think, for terror birds. I might be wrong.

There might be something out there that somebody's discovered or something is somebody's found quite recently. But I think this is probably something that needs to be discovered. We need to find terrible eggs and terrible nests

and get a better idea of how they raise their young. And I'm sure the fossils are out there. Yeah, absolutely. And looking forward to seeing what comes out of the ground in the future.

We come on, let's get to the end of the age of terror. So, terror birds have been apex predators

“in South America as an island for tens of millions of years.”

But then what happens? Something happened. Something big happened. And as is often the case in Earth history, the Earth is four and a half billion years old.

And the Earth is always changing.

And sometimes it's an asteroid that arrives from the heavens. Sometimes it's big volcanoes or other changes that happen to the physical Earth. Sometimes the big changes are just the simple side effects of the continents of the Earth slowly moving

as they always do. So continents are moving now, the ground beneath our feet is moving about at the pace our finger down. - It's hate it shaking. - But I don't feel it, yeah.

But sometimes yes, it does move more than others. And when there's a big earthquake, it might shift a lot more. But the Earth is always in motion. And South America became an island continent because it split away from the rest of those southern lands

that were once part of Pangea, the supercontinent. Then South America would cease to become an island continent because of those same processes of plate tectonics, of continental drift of the Earth moving around.

What happened was about two and a half million years ago

give or take, South America and North America approached each other. And ever so slightly, fingers of land from both, but especially from the North touched at what is the Ismith the Panama. And that's where the Panama Canal is today,

the easiest place to dig a canal between the Pacific and the Atlantic. If there was no Ismith the Panama, you need no canal. That's a very recent geological phenomenon. Now when that happened, probably for a few million years

before the land was close enough that some species could maybe move from North to South just hopping across islands, maybe even swimming. There's some evidence that terror birds may have actually gotten to North America

before the land actually touched. - Oh, okay. - Not a long time before, but a little bit before. It all comes down to how accurately some of these bones and age shells can be dated.

Now that I say age shells, I'm pretty sure there are terror bird age shells from North America. - Okay, fair enough.

“- I think it's through, the gears are turned in a real time.”

But about two and a half million years ago,

North and South America properly connected. And that meant there was now a land corridor. And that land corridor acted like a super highway. And there were animals that were streaming northwards from the South and animal streaming southwards

from the north. This is when you get the ancestors of things like alpacas and llamas going down into South America. They've only been there for a little bit of time. They came from the north.

They're used to be camels in North America. That's what gave rise to these things. Jaguires and other big cats, bears, dogs. These kind of things that are now the top predators in South America, they came from the north.

Meanwhile, there were things like some marsupials, possums that came from the south up north. And now we have them at home, they're all over the Midwest, where I'm from. There are things like some of the really interesting mammals

like armadillos. They're southern. - Really? - They came north. - That's why they're across the way.

- The giant one, we get the giant one. - And there were giant ones as well. They went extinct during the ice age at the end of the ice age. But there were armadillos, the size of cars, and they came from the south and moved north.

So you had animals moving both ways. And that was just a huge disruption. It was just a time of migration, a time of dislocation. And when all was said and done, the terror birds just melted away.

And it's not clear if they were out competed necessarily by Jaguires or bears. They could have been on their way out otherwise. There was climate change happening, of course,

changes around that time.

“That's when the ice age is proper, we're starting.”

So the earth was getting much colder. And some of these terror birds reach north America as well. And they died out there too. So it really is a bit of a mystery as to exactly how they died. A lot of people will say it was because they were outcompeted

by these cats and these bears and these dogs, these placental mammal carnivores, as possible. But the story might be more complex. What we do know is that the very last terror birds did die. They disappeared from the fossil record.

Really just a few tens of thousands of years or so

before the first humans got to South America.

So we did not kill them. This one wasn't our fault. Other bird extinctions, elephant birds and Madagascar Moaz on New Zealand, Dodo's, that's because of us. But this one wasn't.

“But we ever, ever so slightly miss that opportunity”

to meet a terror bird. Maybe a good thing. But two, good thing. And it is still a great story to tell. It would have been incredible to imagine,

if there was something in human legend in the oral stories that passed down from somebody meeting a terror bird. I mean, we just miss that opportunity. You know, we just miss the opportunity for somebody to paint a terror bird on a cave wall.

I mean, can you imagine? Oh, dear, I said you'd have a whole host and new characters.

Yeah, and I always have that image of like,

I mean, save two tigers meeting a terror bird. Yeah, and they would have. They would have their worst saber two tigers that lived in the north that came south when that interchange happened.

“So there would have been some overlap there.”

I would go, God knows if they came into a comment. I don't know. I don't know. That's for the movie makers. Well, exactly, that's the image you sometimes get

at the saber two from the terror bird, don't you? I'm Steve, this has been absolutely brilliant. And hopefully introduction and explanation if the weird and wonderful world of terror birds. And for how long they dominated South America

from they are just parts of your brilliant new book. Which is cool. It's called The Story Birds. And it is a pop science book. It's not an academic book.

It's not a textbook. It is the story of what birds have done

for the last 150 million years.

How they evolved from dinosaurs, how some dinosaurs got feathers and wings and started to fly, how these feathery wing ones were the only ones to survive the asteroid. And then the amazing things they did afterwards, including things like terror birds,

but also the evolution of cognition and crows. And beautiful songs and many songbirds and the long migrations that birds have, all the amazing things birds do today. So it's similar to my previous books,

Rise and Fall of the Dinosaur, as a rise in reign of the mammal. These are pop science books that try to tell these grand stories about evolution. - Out of course, for our next episode,

penguins. - Yes, penguins. Maybe even more terrifying than terror birds, I'm just leaving that hanging. - It's a great game. - And wouldn't think so, but stay tuned.

- Stay tuned, indeed, for that. - Right, yes, we'll see you in a bit. Steve, this has been absolutely brilliant. - It's an awesome pleasure. - Thank you. - Thanks so much for joining us on the ancients today.

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