Terror Birds

The Ancients

This episode of 'The Ancients' explores the fascinating prehistoric apex predators known as terror birds—massive, flightless carnivores that dominated South

Key takeaways

• Terror birds were apex predators that evolved after the dinosaurs' extinction, thriving for tens of millions of years in isolated South America.
• They lost flight to grow larger and become more powerful, making them formidable hunters despite being birds.

Main topics

• Evolution and biology of terror birds
• South America as an isolated island continent during the age of terror birds

Notable quotes

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.

Conclusion

Terror birds represent a remarkable chapter in Earth's evolutionary history—monstrous, flightless predators that ruled South America for millions

Transcript preview

Speaker 4 (0:00) Ever wondered why the Romans were defeated in the Teutoburg Forest? What secrets lie buried in prehistoric Ireland? Or what made Alexander truly great? With a subscription to History Hit, you can explore our ancient past alongside the world's leading historians and archaeologists. You'll also unlock hundreds of hours of original documentaries with a brand new release every single week covering everything from the ancient world to World War II. Just visit historyhit.com slash subscribe. Speaker 3 (0:32) My name is Jonathan Sims. I work for the Magnus Institute London, an organisation dedicated to academic research into the esoteric and the paranormal. Statement begins. Speaker 4 (0:44) Next morning, however, he was found lying on Speaker 3 (0:46) the water. And I am down. It's going to hurt. Speaker 4 (0:56) Listen to the Magnus Archives at tophorrorpodcast.com Speaker 4 (1:04) They are the biggest birds to have ever lived. Apex predators that roamed the plains of South America for millions of years. Mega carnivores that followed the dinosaurs. Flightless, yet monstrous. Scientifically, they are known as forest rackets. We know them simply as terror birds. 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 Terror Birds. Our guest is Dr Steve Brassati, Personal Chair of Paleontology and Evolution at Edinburgh University and the author of The Story of Birds. Speaker 4 (2:13) Steve, it is so good to have you back on the show. Speaker 2 (2:15) Tristan, it's 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. Speaker 4 (2:25) 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 a few million years after. Speaker 2 (2:34) Yeah, and as we'll see. Still kind of was the age of dinosaurs because birds are dinosaurs. We can get to that, of course. Speaker 4 (2:43) And these are the terabirds. That's right. They seem and sound so bizarre to have ever existed, but they did. They Speaker 2 (2:51) 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 terror birds are a great example of that. These were birds that would have been terrified. The nickname 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. Speaker 4 (3:34) Not just millions of years, tens of millions of years. Speaker 2 (3:37) And Speaker 4 (3:37) I probably butchered the naming of it, the pronunciation of its scientific name in the intro. How do we say it? Speaker 2 (3:44) Oh, you're asking. Oh, my God. That was the one thing I was hoping you wouldn't ask. I don't know. So it's a name that goes way back. Speaker 3 (3:55) The Speaker 2 (3:55) Amegino brothers in Argentina, these were basically the family. There were 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 saber-toothed tigers and woolly mammoths and all 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 anteater or, you know, a sloth or an armadillo, something like that, which makes sense because these kind of animals, mammals live in South America. But as it turned out, a few years later, their mistake was corrected. And yes, it was a jaw. Yeah, it 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. Forus, yeah. Yeah, so it's forus arachids or something like this. Forus arachid, okay, yes. Yeah, and so P-H-O-R, you know, but there's a reason why. They're called the terror birds because they're terrifying. Obviously, it's Speaker 4 (5:38) a Speaker 2 (5:38) 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 for the rest of this chat. I should have been better prepared. This is why, so, you know, the book you mentioned, The Story of Birds, I think it's behind me there. So I have Speaker 4 (5:54) a Speaker 2 (5:54) whole chapter on 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 soul to do. Speaker 4 (6:05) Well, okay. So the terror birds, when are we talking? If they're apex predators for tens of millions of years, which tens of millions of years should we be thinking of? Speaker 2 (6:14) So as always with the fossil record, we don't exactly know when the very first terror birds lived. But we can say that the oldest fossils come from what's called the Eocene time. And 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 and the classic dinosaurs went 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. The last ones went 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 one we're absolved of 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. Speaker 4 (7:44) We'll explore that extinction part at the end. Speaker 2 (7:48) let's say roughly 50 some 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. It 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 his 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. Speaker 4 (8:20) I'm jealous you've got terror birds compared to here Speaker 1 (8:22) where Speaker 4 (8:22) we didn't. But that's another story. But you 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. Speaker 2 (8:34) 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 Pangaea, which was the single supercontinent. So Pangaea 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. connected to Africa for a long time. That's why they look like puzzle pieces that fit together, because they did for a long time. But Australia was part of that Gondwanan continent. So was Antarctica. So was Madagascar. So was India. India used to be part of the South. It's only very recently moved northwards. Then that Gondwanan 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 its own right, but an island divorced from everywhere else. And so because it was isolated, the animals there, the plants there, they evolved in 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. Speaker 4 (10:01) So we set the scene. So it's South America for the story of the terror birds, largely when it was an island. So now let's explore kind of getting to terror birds and the story, that evolution story is so interesting. And I feel we should probably start with the extinction of the dinosaurs. So 66 million years ago, what happens? Oh, Speaker 2 (10:22) the worst day 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 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 beeline 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 Yucatan 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 a 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 in four chance of survival really Speaker 4 (12:21) and it's in those following Years months and years that the extinctions really happened because of entering that nuclear winter time