Prehistoric animals rock! How much do you know about these unusual beasts? Join Brains On! host Molly Bloom as she tests the prehistoric animal knowledge of co-hosts Samaya, Roscoe, Zana, and Arjun! The games begin in the Permian Era, almost 300 million years ago, when giant dragonflies buzzed through the skies. Play along and you’ll wind up in the most recent Ice Age, when saber-toothed cats prowled the California coasts! Plus, you’ll get to hear prehistoric animal haikus and a not-so-prehistoric mystery sound!

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SPEAKER 1: You're listening to Brains On, where we're serious about being curious.

SPEAKER 2: Brains On is supported in part by a grant from the National Science Foundation.

MOLLY: I am so excited. Today, we're doing a quiz show all about prehistoric creatures, specifically, we're focusing on the cute critters that lived before the dinosaurs in a time called the Permian era. Dinos are cool, but it's time their ancestors get some love, too. Let's make sure I'm ready.

OK, I've got all my note cards for the Brains On quiz show. I've got my purple velvet game show tuxedo. This is going to be epic. But am I satisfied with just epic? I think it could be even better. But I need help. I need someone who can create whole worlds with sound, an audio ace, a noise ninja. I need--

paging Marc Sanchez to the sound station. Marc, please report to the sound station.

MARC: Hey, pal, you called? Wow. Wow. Wow. That is a sharp-looking tuxedo.

MOLLY: I know, right? Oh, Marc, I need your help with some sound wizardry. I want to set the prehistoric scene, and I want everybody to really see what the world was like then. But you know it's a podcast, so see with their ears.

MARC: Oh, man, sounds like fun. Let me fire up the old sound machines here. OK. What am I working with?

MOLLY: We're journeying back to the Permian era, almost 300 million years ago before dinosaurs evolved. No T-rexes, no stegosauruses, and not one single triceratops. All of the continents on Earth were smushed together into one big landmass, surrounded by lots and lots of oceans. There were huge icy glaciers to the south. But over millions of years, the climate gradually got warmer and warmer, and the glaciers began to melt.

MARC: Some drips and drops for the melting glaciers.

MARC: OK, what about plants?

MOLLY: At the equator, right around the middle of our planet, rainforests began to grow. The first plants to have seeds evolved around this time. Some of these plants are still around today, like the ginkgo tree, with its fan-shaped leaves.

MARC: OK, here's the breeze, blowing through the rainforest trees and some foresty noises.

MOLLY: Dude, there weren't any clowns in the Permian, not even a clownosaurus.

MARC: Whoopsies. Sorry. Maybe some bugs buzzing around? Were there bugs?

MOLLY: Oh, there sure were. Early relatives of cockroaches and grasshoppers, plus the very first beetles. There were also giant dragonflies that could grow to the size of your whole arm.

MARC: Gotcha. OK, here comes one now.

MOLLY: Marc, I don't think they sounded like that.

MARC: Well, Molly, sound doesn't fossilize. Who knows what they sounded like?

MOLLY: I think we can make a pretty educated guess about this. They probably just sounded like other bugs.

MARC: What's that, Molly? I can't hear you over all these giant prehistoric dragonflies. There's so many. Duck.

MOLLY: You're listening to Brains On from APM Studios. And I'm so excited because, today, we're talking about prehistoric creatures. It's a whole episode all about the incredible animals that lived millions and millions of years ago. You've been sending us amazing haiku poems all about your favorite prehistoric creatures, like this one from Samaia.

SAMAIA: Giant glyptodons, enormous armadillos weighed more than two tons.

MOLLY: That was Samia from Berkeley, California. And she's here with us today. Hi, Samaia.

SAMAIA: Hello.

MOLLY: So I'm wondering, if you could visit prehistoric times, would you want to?

SAMAIA: Maybe, but-- maybe I just want to see them, but maybe not get too close, since it sounds kind of scary.

MOLLY: Yeah, probably good to keep our distance from these giant creatures. Because we don't know what they're going to do to us. The plant eaters, maybe they would be willing to get a little pat on the head, but we're not sure. We don't know. So what do you think the prehistoric times smelled like?

SAMAIA: I don't know. Like, plants, maybe?

MOLLY: Yeah, I think plants is, right? Because it's all natural world, right? Nothing made by people. Is there somewhere you've been in your life that you think might be the closest to smelling prehistoric times?

SAMAIA: Well, I've been backpacking in the Sierras, and maybe that, since there's a lot of nature.

MOLLY: Yeah, so maybe that's similar because, yeah, there's not a lot of human made things around there.

SAMAIA: Yeah, and there aren't that many people.

MOLLY: Very cool. We're going to start our show by learning about some creatures from the Permian era. That's the long period of time right before the first dinosaurs showed up on Earth. And I hope, Samaia, that you're up for a challenge because you'll be joining us for a game we're calling--

SPEAKER 3: How big was it?


MOLLY: The game is in the name. First, I'm going to tell you about a living thing from the Permian era, and you have to guess how big it was. But don't worry, I'm going to give you a few answers to pick from. All right, Samaia, let's get to it. It's time to play how big was it? Here's your first thing. It was called meganeuropsis permiana. It looked like a dragonfly, and it was big.

SPEAKERS: How big was it.?

MOLLY: It was so big, that scientists think it might be the largest insect to ever roam planet Earth. It had four wings, six legs, and a long tail. Roughly speaking, how big was its wingspan, meaning how wide did its wings go?

Was it A, as big as a football, B, the length of a tennis racket, C, the length s a hockey stick, or D, the length of an Olympic-sized pool. So which one of these is how big this giant dragonflies wing's spread? Football, tennis racket, hockey stick, or Olympic-sized pool.

SAMAIA: I think, maybe, tennis racket.

MOLLY: Excellent guess. And you are correct. Hooray. The answer is the length of a tennis racket.

SAMAIA: Since Olympic pool seems too big.

MOLLY: That would be a very, very big dragonfly. These enormous insects had a wingspan, around 28 inches. Scientists believed they were predators that buzzed above swamps, gobbling up other insects, and even small amphibians.

Next up, another creepy crawler. This one is called arthropleura, and it was a prehistoric millipede. Picture a long segmented creature, slithering across the landscape on dozens and dozens of legs. It was so big.

SPEAKERS: How big was it?

MOLLY: It was so big, scientists think it might be the largest arthropod ever. Remember, arthropods are the group of animals that includes crabs, insects, millipedes, and centipedes. How long was this prehistoric millipede? Was it A, the length of a Subway sandwich, B, the length of a baseball bat, C, the length of a broom, or D, the length of a car?

SAMAIA: I think, maybe, B, the broom.

MOLLY: The broom. The answer is the length of a car.

SAMAIA: Whoa, that's really long.

MOLLY: Well, scientists think this mega millipede was around 9 feet long and weighed more than 100 pounds. Wow, imagine seeing something like that on your daily walk.

SAMAIA: Wow, I'd probably look at it for a little bit, but then run away. Because I'd be like, what is it?

MOLLY: Yeah, like, is it a car? Is it a new kind of vehicle? No, it's running towards me. Well, next, we have a creature called moschops, which is Greek for calf face. It had a thick, sloped neck, four legs, and looked like someone put a lizard face on a rhinoceros body. This burly beast was a therapsid, a group of animals that were technically reptiles, but they had a lot of features that we would later associate with mammals, like us. It was so big.

SPEAKERS: How big was it?

MOLLY: It was so big, it's considered one of the largest plant eaters of its time. So did this moschops weigh roughly the same as, A, a refrigerator, B, a tractor, C, a school bus, or D, the entire Denver Broncos football team, if they were also holding a bowling ball. Which one do you think? Refrigerator, tractor, school bus, or an entire football team.

SAMAIA: I think school bus.

MOLLY: And the answer is, actually, a refrigerator. So they were big, but not nearly as big as the dinosaurs that would come later. So what's interesting about these moschops is that they had very, very thick skulls.

Scientists think they would butt heads as a sort of competition, which suggests they were social creatures, even if the social stuff involved smashing heads together. Well, great work, Samaia. Have you heard of any of these creatures before today?

SAMAIA: I don't think so.

MOLLY: OK, now you got to tell all your friends about giant millipedes, giant dragonflies, and a strange rhino lizard called moschops, OK?


MOLLY: OK. Thank you so much for playing with us.

SAMAIA: Thank you.

MOLLY: Bye Samaia.

SAMAIA: Goodbye.

SYNTHESIZED VOICE: Brains, Brains, Brains On.

ADISH: Megatherium, gigantic sloth of the past, I wish you were here.

ABBY: Look up in the sky. It's a giant dragonfly, a maganera.

MOLLY: Thanks to Adish and Abby for sending in those great haikus. Now, joining us for this prehistoric party is Roscoe from Mankato, Minnesota. Hey, Roscoe.


MOLLY: So you sent in a haiku about one of your favorite prehistoric creatures. Can you recite it for us, please?

ROSCOE: Yeah. Sabertooth tiger, its fangs are long and gnarly. Can't find the dentist.

MOLLY: I love that haiku. It has a great joke in it, which is not easy to do in only a few syllables.


MOLLY: Roscoe, are you ready to play a game?


MOLLY: This game is called--

SPEAKER 3: Prehistoric beastie or pure fantasy.

MOLLY: In each round, you're going to meet two creatures who will describe themselves to you. One of them was actually alive here on Earth during the Permian era, and the other is a mythical creature, meaning it's imaginary. So your job is to guess which was real. Are you ready?

ROSCOE: Yes, I am.

MOLLY: Awesome. So first up, we're going to meet a creature called Eryops.

ERYOPS: Hello. Well, let's see. I'm an amphibian, and I'm pretty big. My biggest relatives measure over 7 feet long and weigh almost 500 pounds. I'm best known for my ginormous flat head and sharp-curved teeth. When I'm not guest starring on award-winning science podcast, you can find me at home at a swamp, snacking on some fishies.

MOLLY: So that was eryops. Now, meet the kappa.

KAPPA: All right, here we go. I'm not quite as large as my friend here. I'm about the size of your average human child, but I'm super strong. I live mostly in rivers and ponds, so I've got webbed hands and feet for swimming. I also have a shell on my back for protection and a beak for hunting.

MOLLY: OK, Roscoe, what do you think? Which was the real prehistoric animal? The giant amphibian named eryops or the aquatic reptile, the kappa Which was real?

ROSCOE: The aquatic reptile is my guess.

MOLLY: OK, what makes you think that?

ROSCOE: Well, it seems like having a shell and a beak seems like more lifelike.

MOLLY: Excellent guess. The answer is, actually, the Eryops was the real creature, that giant amphibian. During the Permian era, lots of things were very big. And so this is an early relative of much tinier amphibians, such as frogs, toads, and salamanders.

The kappa is a supernatural creature from Japanese mythology. Some stories depict the kappa as dangerous and unfriendly to humans, while others depict them as helpful and kind.

ROSCOE: That makes sense now.

MOLLY: Makes sense now?

ROSCOE: Yeah, because a lot of ancestors-- or animals alive today had a big ancestor.

MOLLY: It's true. It's very true. All right, here's the next pairing. We've got jackalopes and cynodonts. Let's meet the jackalope first.

JACK: Jack Von Drope, the jackalope here. I bet you can guess how I got my name. Body like a jackrabbit, horns like an antelope. I'm best known for my ability to mimic the sounds of other animals and run really fast, up to 90 miles per hour.

CYONODONT: And I'm a cynodont. My appearance isn't quite so revealing. I look like a small mammal, maybe a mole rat. But I'm actually a reptile. Look closely. See how my legs are spread out to the side of my body, instead of underneath? And just other reptiles, I lay eggs.

MOLLY: Roscoe, what do you think? Which one was the real creature? The jackalope or the cynodont?

ROSCOE: So easy. The cynodont or whatever. Because I know that a jackalope is not real because I have a stuffed version of it, and my parents say that it's not real.

MOLLY: You know so much, you are correct. Excellent work. Does your stuffed jackalope have a name?

ROSCOE: I call him jackalope.

MOLLY: Nice. Well, so the cynodont is a really cool creature, that real one. This egg-laying reptile is a distant relative of modern mammals, even though it's a reptile. So jackalopes, like you know, are mythical creatures said to live in the American West.

The first jackalope was made by two brothers who took a rabbit they had stuffed and put antlers on it for fun, like you do. So from there, the legend spread. And some people still believe that it's real. We have one more pairing for you, Roscoe. Here's the cipactli and the dimetrodon. Let's start with the cipactli.

CIPACTLI: Hello. I'm a bit of an odd duck. Well, I'm not a duck at all. Actually, I'm like a crocodile, but also a fish and a frog, too. But all of those creatures have one mouth. I've got a ton, one at every single joint. I'm a baddie.

MOLLY: OK, Roscoe. Now, let's check out dimetrodon.

DIMETRODON: Oh, hey, I'm a dimetrodon. I'm a giant reptile, with a super long tail. I live in wetlands, and hey, check my sail. Pretty cool, huh? It's made up of long, spiny bones that stretch up from my back, and it's covered in skin, so it looks like the sale of a boat.

MOLLY: OK, Roscoe, which is the real prehistoric creature? The cipactli, with its many mouths, or the dimetrodon, a creature with a giant sail on its back?

ROSCOE: Easy. The dimetrodon, because the creature was so many mouths like that would not exist.

MOLLY: Guess what, Roscoe, you're correct. Very nice work. So dimetrodons lived between 280 to 265 million years ago during the middle of the Permian era. They're often mistaken for dinosaurs, but they were actually a distant relative of modern mammals.

Cipactli comes to us from Aztec mythology. According to the myth, the four creation gods defeated cipactli and created the Earth from his body.

ROSCOE: That's pretty cool. Although it's not real it's mythology, but still pretty cool.

MOLLY: Yeah, mythology can be super cool, too, really good stories. So Roscoe, excellent work. Thank you so much for playing. Before we let you go, we have one more thing for you to guess. Because it's time for the--

SPEAKER 4: Mystery sound.

MOLLY: Are you Ready


MOLLY: All right, here it is.


OK, Roscoe, what's your guess?

ROSCOE: My guess is that it's like a computer program trying to imitate a way a dinosaur roars and stomps.

MOLLY: I like that, because you heard some rhythmic pounding.

ROSCOE: And it's also sounded like it was the drill, a power tool.

MOLLY: OK, so it's either a dinosaur stomping and growling or a power tool.

ROSCOE: Yeah, I think it might be some kind of power tool and maybe trying to use to unearth dinosaur bones?

MOLLY: Ooh, very nice guess. Well, we're going to be back with the answer in just a bit.

ROSCOE: So keep listening.

SPEAKERS: Ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, Brains On.

MOLLY: Hi, friends. We're working on an episode about why we're, sometimes, afraid of the dark. But the dark is also totally cool. So we want to know, what do you love about the dark? Does it feel mysterious? Exciting? Do you like telling stories around a campfire?

Are you a night owl? Do you think nocturnal animals, like possums, are awesome? We want to hear from you. Record yourself, describing what you love about the dark, and send it to us at And while you're there, you can send us questions, like this one.

SPEAKER 5: My question is, how does an engine work?

MOLLY: Again, that's And keep listening.

ROSCOE: You're listening to Brains On. I'm Roscoe.

MOLLY: And I'm Molly. Before the break, we heard an extra tricky mystery sound. Let's hear it again, Roscoe. Are you ready?




OK, Roscoe, any new thoughts?

ROSCOE: I'm still thinking it's a power tool, but the fodding might be amplified, so-- mystery sounds are usually amplified.

MOLLY: Yeah, these mystery sounds are tricky. Because even if it's something you've heard a lot and you hear it out of context, it's hard to describe what it is. I don't know what this is either. I think this one might be someone doing a dance while brushing their teeth with an electric toothbrush, because they want to get their cardio exercise in while also brushing their teeth. Are you ready for the answer?


MOLLY: OK, here it is.

ABEGAIL: Hi. My name is Abegail, and that was the sound of me vacuuming the stairs.


ROSCOE: Well, a power tool.


ROSCOE: It did use power.

MOLLY: Absolutely. A vacuum is a kind of power tool. I will give you that, for sure. Yeah, and I guess that thumping sound you heard must have been like her on the stairs or the vacuum on the stairs.


MOLLY: Very good job. Well, Roscoe, it's been a delight to chat with you today. Thank you so much for coming to play our game and guessing the mystery sound.


MOLLY: Bye, Roscoe.



TYRUS: Terra bird, deadly, breaking skulls and eating flesh. A terra bird.

MOLLY: That terrifying and terrific haiku was from Tyrus.

MARC: Wow, Molly, I had no idea so many incredible creatures walked the Earth before dinosaurs evolved. So many different shapes and sizes. But what happened to them? Why don't we still have giant millipedes the size of cars and reptiles with big bony fins on their backs, which probably sounded like this.


MOLLY: Well, a lot of them disappeared at the end of the Permian era, around 250 million years ago. It was the biggest extinction that has ever happened on Earth.

MARC: What happened?

MOLLY: Some researchers think it might have been an asteroid slamming into Earth, just like the one that caused the extinction of the dinosaurs, millions of years later.

MARC: Oh, I've got the perfect sound for that. It's this button right here.


MOLLY: But lots of other researchers think that it was climate change. See that big jumble of continents these creatures lived on? It wasn't just sitting still. The chunks of the Earth's crust floated on top of a layer of melted rock or magma. Oh, very nice magma sounds, Marc.

MARC: It's my specialty. Oh, keep going. I have tons more sound effects I can use.

MOLLY: The pieces of crust were slowly moving in different directions. Sometimes, pulling away from each other. Sometimes, bashing into one another.


All that smushing and smashing made the melted rock underneath release a lot of gas into the air.

MARC: Too easy, Molly. I've got the perfect sound effect.


MOLLY: Yes, perfect. But these weren't like regular farts. They were volcano farts, and a lot of those volcano farts were made of carbon dioxide, the same gas that's causing climate change today. So back then, the ocean warmed up a bunch, and almost all of the plants and animals living in it couldn't survive the hotter temperatures. Lots of plants on land died out, too. And on land and sea, the food chains got all messed up. Around 70% of animal species on land went extinct.


Sad trombone, for sure. But fortunately, lots of those plants and animals left fossils, so scientists today can look at them and learn what the planet was like during the Permian era.

MARC: I wonder if they had ancient Permian sound effects machines, like mine. I guess we'll never know.

MOLLY: Yes, one of Earth's great mysteries. Coming up, we're going to learn about other prehistoric creatures from other eras because the past is chock full of rad ancient animals. So stick with us for more blasts from the past.

SPEAKER 5: Brains On.

PAISLEY: Sly megalodon up to 60 feet in length, weighs 50 whole tons.

CHARLIE: Eurypterida, scorpions evolved from you. Yay, go, scorpions. Bye.

MOLLY: Thanks to Paisley and Charlie for sending in those awesome haikus. Today, we're playing games, all about the amazing ancient creatures that once roamed the Earth. Here for our next game is Xana from New Bedford, Massachussettes. Hi, Xana.


MOLLY: We are so happy you're here. You wrote us a lovely haiku. Can you recite it for us, please?

XANA: OK, so it's about my favorite dinosaur, euphlocephalus. It's really cool. It's like a smaller ankylosaurus.

MOLLY: Awesome.

XANA: Euphlocephalus, whoa, watch out for its club tail, covered in armor.

MOLLY: Oh, so good. I love that it had action in just a few syllables. There was something happening. A whole story was told. Very impressive. So what is it about you euphlocephalus that you love? Why is it your favorite?

XANA: I like that it's a plant-eater, but it also has a little spark of fierceness in its club tail. And I like it better than ankylosaurus because I like dinosaurs that people don't know that much about.

MOLLY: So you to be able to be like, have you heard of euoplocephalus? Well, let me tell you.

XANA: Yeah.

MOLLY: Cool. So, Xana, our next game is called.

SPEAKER 3: Ancient firsts.

MOLLY: Not ancient farts, which is a totally different and much smellier game. In this game, I'm going to give you two different traits of living things, like eyeballs or webbed feet, and you're going to tell me which one came first.


MOLLY: OK, let's give it a try. Here's the first one. Animals with backbones or animals with lungs, which one came first? Backbones or lungs?

XANA: I'm going to say backbones because I know fish have backbones.

MOLLY: You're 100% correct. Nice work. Yeah, so the first animals with backbones were fish, just like you said, and they evolved about 480 million years ago. Then about 400 million years ago, some of these water-dwelling animals started evolving other characteristics that helped them move out of the water and onto land, like lungs and limbs. OK, are you ready for another ancient first?

XANA: Yeah.

MOLLY: All right, so which one came first? Plants with flowers or plants with seeds?

XANA: I'm going to say, definitely plants with seeds because most plants spread with seeds, and I know flowers evolved in the Cretaceous period.

MOLLY: Oh, Xana, you are correct again. Amazing work. Yeah, so the first plants with seeds evolved more than 300 million years ago. Scientists have found fossils of what they think is the oldest known plant with seeds, which looked like a fern with rows of seeds on it. And the first flowering plants came much later, like you said.

XANA: Yeah.

MOLLY: OK, we have one more ancient first for you. You ready?


MOLLY: Which do you think came first? Animals with scales or animals with feathers?

XANA: I do know feathers were around before dinosaurs, but I think-- well, I heard that in your narwhal episode, when they go to the shop with teeth, in it, they were talking about-- there was some teeth that were on the outside of a fish's, like scales. I don't know if that counts, but I think scales were probably first.

MOLLY: Xana, once again, you are correct. Such good reasoning. I love how you're drawing on everything to make these amazing answers. So the first scales evolved more than 400 million years ago on ocean-dwelling creatures. And then when the first sea creatures started to move on to land, they had scales.

And the first feathers evolved only about 175 million years ago. And like you said, dinosaurs had feathers. Well, Xana, thank you so much for being here. You are a prehistoric expert yourself, so I'm so appreciative you shared your knowledge with us today. So thank you so much for being here.

XANA: You're Welcome.

EHECATL: The quetzalcoatlus, giant flyer in the sky.

CLAIRE: Great big and woolly, they are nice gentle giants. Long tusks, herbivores.

MOLLY: Ehecatl and Claire sent us those haikus. So good. Next up is Ajun with us, from Sydney, Australia. Good morning, Ajun.

AJUN: Good morning, Molly.

MOLLY: So when we're taping this, it's after noon for me, but it's actually tomorrow morning for you. So Ajun, how's the future? How's tomorrow going?

AJUN: Pretty good.

MARC: Excellent. You sent us a haiku. Would you please read it for us?

AJUN: So dinosaur lived in the late Cretaceous. Its name is troodon.

MOLLY: OK, so I know from your haiku that it's very smart, but what else about this cool creature? Tell us about it.

AJUN: It was thought to have feathers. It did live in the late Cretaceous, so it did live alongside all the bigger dinosaurs, like T-rex and stegosaurus and all of those well known dinosaurs. Also, it was pretty small, but we know that it was very smart from the way it hunted its prey.

MOLLY: So how did it hunt its prey?

AJUN: It would have hunted in a pack. While one troodon was distracting the prey, three other troodon would enclose it from all the other directions.

MOLLY: Well, my friend, are you ready to play a game today?

AJUN: Yes.

MOLLY: Excellent this one is called--

SPEAKER 3: A couplet of creatures.

MOLLY: So here's how it'll work. I'm going to read you a couplet, which is just two lines of a poem that rhyme, but the last word in the couplet will be missing. So it's going to be your job to fill in the mystery word and complete the rhyme. It's going to go something like this.

Here's an example. I'm like a furry elephant, known for my brawn, smaller than a mammoth, I'm a-- and the answer is mastodon. So that's how it's going to work. We're going to have you guess the last word of the rhyme. All right, here is the first couplet. Are you ready?

AJUN: Yeah.

MOLLY: I'm related to an animal covered in moss, and I'm known for moving slowly. I'm a giant--

AJUN: Sloth.

MOLLY: Nice work. So we giant sloths were massive vegetarians that spent their days waddling through the forests of North and South America, snacking on twigs and leaves. The biggest species of ground sloth, megalonyx, was 10 feet long. When they stood up, they were as tall as a basketball hoop. All right, ready for the next one?

AJUN: Yes.

MOLLY: Here we go. Hiss, meow, where's my prey at? Got daggers for teeth. I'm a saber tooth-- the opposite of what we were just discussing.

AJUN: Saber-toothed cat?

MOLLY: Yes, correct. Saber-toothed cats were powerful predators native to North and South America, with muscular bodies perfect for ambushing their prey and two fangs as long as chef's knives. They were at the top of the food chain. OK, you ready for your last couplet?

AJUN: Yes.

MOLLY: I'm a giant armadillo. Call me glyptodon. Big as a car, I'm up to 10 feet--

AJUN: Long.

MOLLY: Correct. Excellent work. So, yeah, glyptodons were dinosaur-sized armadillos, looked like Volkswagen beetles. And at 5 feet long, their armored shells would have been about as big as a camping tent. And there is some evidence that early human settlers in South America took shelter under abandoned glyptodon shells. Ajun, thank you so much for being here and playing this game with us today and sharing your amazing dinosaur knowledge.

AJUN: You're welcome, Molly. Thank you for letting me be in.

MOLLY: And now, one more haiku before we go.

NOAH: Saber-toothed tiger, sharp teeth, warm fur, great hunter. Sadly went extinct.

MOLLY: Thanks to Noah for that excellent haiku. And that's it for this episode of Brains On. This episode was written by Rosie DuPont, Nico Gonzales Wisler, Shahla Farzan, and Sanden Totten, with production help from me, Molly Bloom, Anna Goldfield, Aron Waldeslassie, and Ana Wegel, Molly Artwick Quinlan, Ruby Guthrie, and Marc Sanchez.

Our editors are Shahla Farzan and Sanden Totten. Sound design by Rosie DuPont and Rachel Briese. Beth Perlman is our executive producer. The executives in charge of APM Studios are Chandra Kavati, Alex Schaffert, and Joanne Griffith. Special thanks to Rachel Stopka, Arvin Thangali, Crystal Jayron, and Ana Girshick.

Brains On is a non-profit public radio program. There are lots of ways you can support the show. One way is to subscribe to our Smarty Pass. You'll get ad-free feeds of each of our shows and some bonus games every month. Check it out at

We'll be back next week with more answers to your questions. Thanks for listening. And before we go, it's time for the Brains Honor Roll. These are the incredible kids who keep the show going with their questions, mystery sounds, drawings, and high-fives.


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