A Tyrannosaurus rex (T-Rex) skeleton, named STAN is on display during a press preview at Christie's Rockefeller Center on September 15, 2020 in New York City. - The skeleton of a 40-foot (12-meter) dinosaur nicknamed "Stan", one of the most complete Tyrannosaurus rex specimens ever found, will be auctioned in New York next month and could set a record for a sale of its kind. Discovered in 1987 near Buffalo, South Dakota, the 188-bone skeleton took more than three years to excavate and reconstruct by paleontologists from the state's Black Hills Geological Research Institute, where it has been exhibited since.
ANGELA WEISS/AFP via Getty Images
Did dinosaurs roar? Or meow? And how do we know? Paleontologist Julia Clarke stops by to talk about sounds T-Rex might’ve made. We know a bit more about other dino sounds, and dinosaur expert Riley Black fills us in on those. Plus, a game about dinosaur names, and a look at how dinos might’ve moved with paleontologist Jingmai O’Connor.
Stick around for the mystery sound, and a Moment of Um that answers this head-scratcher: How does hair dye work?
Audio Transcript
Download transcript (PDF)
KOBE: You're listening to Brains On where we're serious about being curious.
SUBJECT: Brains On is supported in part by a grant from the National Science Foundation.
[GROWLING AND STOMPING]
[MMM]
[HOWLING]
SANDEN TOTTEN: Hey Molly and Kobe.
MOLLY BLOOM: Hey, what are you up to Sanden?
KOBE: Imitating a petting zoo?
MOLLY BLOOM: Or activating your voice commands for Harvey?
SANDEN TOTTEN: Close, we're practicing the noises we think dinosaurs might have made.
[GROWLING AND STOMPING]
KOBE: I like the stomping.
SANDEN TOTTEN: Molly, do you have a dino impression? MOLLY BLOOM: Hm, yeah. [POOT] [LAUGHTER] A toot, that's probably a plant-eating dinosaur.
SANDEN TOTTEN: Don't you think dino farts would be bigger? I think it'd be more like--
[LONG FART]
What about you, Kobe, what do you think dinosaurs might have sounded like?
KOBE: Well, what if T-Rex actually sounded like meow?
[MEOWING]
MOLLY BLOOM: You're listening to Brains On from American Public Media. I'm Molly Bloom. And my co-host today is Kobe from San Mateo, California. Hi, Kobe.
KOBE: Hi.
MOLLY BLOOM: Kobe, you wrote to us with a really great question about dinosaurs.
KOBE: How do scientists know what sounds dinosaurs used to make? What if T-Rex actually made really cute sounds like a kitten?
MOLLY BLOOM: So Kobe, how did you think of that question? How did it pop in your head?
KOBE: Oh, I think I was watching a documentary on dinosaurs. And I thought, is that really what they sound like?
MOLLY BLOOM: So what kind of sounds do you imagine other dinosaurs making?
KOBE: Maybe they made sounds kind of like a bear or a-- like a tiger or a lion.
MOLLY BLOOM: So a little more fierce than a kitten, perhaps?
KOBE: Yeah.
MOLLY BLOOM: So this is our second episode all about what dinosaurs were really like. In the first episode, we took a look at dinosaur colors.
KOBE: Plus, if dinos tooted. Definitely check it out.
MOLLY BLOOM: This time, we're taking a look at other parts of dinosaurs' lives.
KOBE: How they might have sounded.
MOLLY BLOOM: And how they stood and moved.
KOBE: Dinosaur fossils give us clues about these things.
MOLLY BLOOM: But if you think about how we talk and move, we use our vocal cords to sing and shout and our muscles to move.
KOBE: It's squishy body parts that do those things, not bones.
MOLLY BLOOM: And squishy body parts, which are also called soft tissue, they don't show up well in fossils.
KOBE: They break down too quickly.
MOLLY BLOOM: Hard body parts fossilize better.
KOBE: Mostly that's bones and teeth.
MOLLY BLOOM: But, lately, scientists have found little bits of soft tissue, along with dinosaur bones, footprints, and poop.
KOBE: Paleontologists have to dig very carefully to find those fossils.
MOLLY BLOOM: And then they study them very closely. They take special 3D x-rays of bones to understand their exact shape inside and out.
KOBE: That helps them think about how all kinds of body parts fit together.
MOLLY BLOOM: They also use powerful microscopes to zoom way in on fossils' tiniest details.
KOBE: That can sometimes show how strong the bones were, which helps you think about how big a dino was and how it moved.
MOLLY BLOOM: And they often compare dinosaurs to living animals too.
KOBE: With all these clues, we can start to come up with ideas about how a long gone animal might have lived.
MOLLY BLOOM: Which brings us to your question about T-Rex sounds, Kobe. When you wrote in, you pointed out that sounds don't show up in the fossil record, which is totally true. So we got in touch with someone who has thought about what Tyrannosaurus Rex might have sounded like.
JULIA CLARKE: My name is Julia Clarke. And I'm a professor of paleontology at the University of Texas at Austin.
MOLLY BLOOM: Julia said, the first thing to think about if you want to imagine what an extinct animal might have sounded like is how big it was.
JULIA CLARKE: One of the things we know about animals is that larger animals generally have deeper voices. They make lower frequency sounds. And small animals tend to make higher frequency sounds, in general. You know, there are rule breakers to everything.
MOLLY BLOOM: So if T-Rex made noises, it would probably have made lower, deeper sounds. But how do we know T-Rex made sounds at all?
KOBE: What if it was more of a silent thinker?
MOLLY BLOOM: Well, Julia looked at T-Rex's closest living relatives.
JULIA CLARKE: So those are crocodilians, alligators and crocodiles and their relatives, and living birds. We can look at both of those groups. And in both of those groups, they're pretty noisy compared to other reptiles.
MOLLY BLOOM: So there's a good chance T-Rex did make sounds. And check out these alligator sounds. These are American alligators, the ones that live in North America.
[DEEP BELLOW]
[GROWL]
And what's really cool is that all of those sounds are made with the mouth closed.
KOBE: Closing your mouth really changes how sound comes out.
MOLLY BLOOM: You can say that again.
[HMM HMM HMM HMM]
So when Julia and her team put together a sound that might have been what T-Rex sounded like, here's what they did.
JULIA CLARKE: We took crocodile sounds and closed mouth vocalizing and open mouth vocalizing birds. And then we basically remixed the frequency of those sounds into the range of something similar to the size of an animal of T-Rex.
MOLLY BLOOM: Now, this is a very deep and low sound. So listen closely.
[DEEP STATIC SOUND]
Kobe, what do you think of that sound? Do you think that's what a T-Rex sounds like?
KOBE: Yeah it sounds a lot like static, like a very low static.
MOLLY BLOOM: Yeah, to me, it kind of sounds like what I imagine it would sound like if they were like stomping on the ground far away from me.
[AUDIO LOGO] Brains, brains, brains on.
MOLLY BLOOM: For some dinosaurs like T-Rex, thinking about their sounds is like a fun thought experiment. For other dinosaurs, fossils do have information about their sounds. We asked Riley Black to fill us in on that. She writes all about dinosaurs.
KOBE: Hi, Riley.
RILEY BLACK: Hi, Kobe.
KOBE: How are you doing?
RILEY BLACK: I'm doing OK. I hear you have a lot of dinosaur questions for me.
KOBE: Oh yeah, the first one is, what kind of fossils can tell us about dinosaur sounds?
RILEY BLACK: Well, that's a really neat question because the fact is that lots of different kinds of fossils can tell us about that. I was thinking a little bit about that question the other day. Because we think about dinosaur noises a lot. Did they roar? Did they scream? Did they honk?
But dinosaurs could actually make lots of different kinds of sounds. We look at animals today, like alligators and stuff. Sometimes they clap their jaws. Or lizards, they rub their scales together to make noise. So there are really lots of different ways that dinosaurs could have made noise or communicated with each other. But when we talk about sounds, kind of like dinosaur voices in a way, those fossils are actually really, really super duper rare.
KOBE: What can scientists reconstruct about these sounds?
RILEY BLACK: There are a few dinosaurs that we have where they have these really neat crests. So you know like hadrosaurs, right, like duckbill dinosaurs. Have you heard of those before.
KOBE: Oh, yeah.
RILEY BLACK: Some of those dinosaurs-- like, there's one from my home state here in Utah called Paracelsus. And that's what this long kind of tube, like a big piece of pipe almost coming off the back of its head. And there's a few relatives like Corythosaurus and Lambeosaurus that they have neat headgear too. And those crests are hollow.
And if you look inside of those, there's a tube on the inside that connects from their nose all through that crest all the way to the back of their throat. And we can figure out through computer models how the air would have moved through those. And we figured that they would have made these really deep honking kind of sounds. So not quite like a duck, but have you ever heard like an elephant, like those low kind of rumbly sounds? Those are the sorts of sounds that these dinosaurs probably made.
KOBE: Oh, that's really cool.
MOLLY BLOOM: So we just listened to Dr. Julia Clarke's reconstruction of what a T-Rex might sound like. And I know she's also studied bird fossils of something called a syrinx. But the syrinx, it's not-- it's not quite a bone, right?
RILEY BLACK: Yeah, so syrinx is made of cartilage. That's the same stuff that's in the tip of your nose and in your ears. It's really flexible. So we usually don't see a whole lot of them in the fossil record.
It's super duper rare that Dr. Clarke was able to find one. And the fact that it was in this bird indicates that this particular organ that allows birds to kind of make a lot of complex sounds, like some of the singing sounds and a lot of the neat things that we think of when we think of birds, it happened relatively late in their evolution. So dinosaurs before that time probably sounded a bit more like alligators and crocodiles and stuff today.
They can probably grumble and they can make these kind of like really low sounds. But they probably weren't doing really complex stuff like a cardinal singing or something like that. So that's what we're really hoping to find more of, are more of these what we call soft tissues, the interior stuff that can tell us sort of what the throat and the airway of these dinosaurs were like.
KOBE: What parts of dinosaur sounds will probably stay mysteries?
RILEY BLACK: Well, one of the neat things about dinosaurs is that we're never going to find all of them. It's kind of sad, but it's also kind of neat that-- because it really highlights how awesome it is that we found so many already. Dinosaurs in the ancient past, we only get their fossils in environments where new sediment like sand or ash or mud or silt were being laid down-- so places like floodplains or the edges of lakes and things like that. Dinosaurs that lived in the mountains, those environments weren't preserved.
So we're never going to know about those dinosaurs and maybe what sounds they made. And there are some dinosaurs that if we have, for example, like a leg bone. And some dinosaurs are only known from a leg bone or for some other part of their skeleton. We may never have the information to find out what that specific species sounded like.
And we know that's important. Because when we look at animals today, even closely related animals can make very, very different sounds. So there's always going to be a place for imagination, for thinking about, well, what could they have possibly sounded like?
And I think that's really, really neat. Because if we had all the answers, it could just be like an encyclopedia. It's the stuff that we don't know that keeps us going back to the fossil record.
KOBE: That's very interesting.
RILEY BLACK: Yeah, this is really the best time in history so far in the history of paleontology to be a dinosaur fan. Not only are we finding more just an incredible rate-- like a new species of dinosaur is named every two weeks. But the technology that we have now to scan these fossils, to understand their chemistry and their anatomy and all that stuff, it's way different than it was 100 years ago, even 20 years ago.
So now if you find a dinosaur fossil, you can tell so much about how that animal lived. And that's really cool. And that's why I'm glad we've been talking about dinosaur sounds. Because fossils are typically very quiet. So it's really fun to imagine what sounds there would have been and then like what evidence would we use to come up with that.
KOBE: Thank you, Riley.
RILEY BLACK: Oh, this was so much fun. Have a good day, Kobe.
[AUDIO LOGO] Brains on, on, on.
MOLLY BLOOM: Here is a sound that is definitely real and not reconstructed. It's time for the--
[WHOOSH]
[DING]
[MUSIC PLAYING] Mystery sound.
MOLLY BLOOM: Here it is.
[SQUEAKING AND CHIRPING]
What is your guess?
KOBE: It sounds kind of like a bunch of electronics, like somebody is fixing something in a jungle maybe. I heard some birds in the background.
MOLLY BLOOM: So we heard some electronics, maybe some birds. Well, we'll hear it again and give you another chance to guess a little bit later in the show.
[MUSIC PLAYING]
We're working on an episode all about time travel and we want to know when you would go in time if you could-- the past, the future. Kobe, when would you want to travel to?
KOBE: I would probably want to travel to the near future so I can do all the things I can't do now because of COVID.
MOLLY BLOOM: I think a lot of our audience feels the same. Well, send your answers to us at brainson.org/contact.
KOBE: And your answer could be part of the episode.
MOLLY BLOOM: Like this question.
SAMEERA: My name is Sameera. And I'm from Philadelphia. And my question is, how does hair dye work?
KOBE: We'll answer that in the Moment of Um at the end of the show.
MOLLY BLOOM: And read the latest additions to the Brains Honor Roll. They're the brilliant listeners that send us their questions, ideas, drawings, and mystery sounds.
KOBE: Send in yours at brainson.org/contact.
MOLLY BLOOM: We love reading and listening to everything you send in.
KOBE: Keep listening.
MOLLY BLOOM: You're listening to Brains On from American Public Media. I'm Molly.
KOBE: I'm Kobe.
MOLLY BLOOM: And this is the mystery sound again.
[SQUEAKING AND CHIRPING]
All right, so last time you heard electronics or maybe birds. What thought do you have now?
KOBE: Maybe like in a lab. I heard like it sounded like there were some like baby birds maybe.
MOLLY BLOOM: OK, well, let's hear the answer.
ZANDER CORBETT: Hi, I'm Zander Corbett. I live in New Zealand. That was the sound of a tui near my house. They only live in New Zealand. And they have two voice boxes at the end.
MOLLY BLOOM: So a tui is indeed a kind of bird. So you were correct. Those were birds.
KOBE: Nice. That didn't sound a lot like any bird I've heard before.
MOLLY BLOOM: Yeah, well, those are birds that are only found in New Zealand. So unless you live in New Zealand, that would not be a familiar bird sound.
[AUDIO LOGO] Ba-ba-ba-ba-ba-ba-ba-ba-ba-ba brains on.
MOLLY BLOOM: You know what's one of my favorite things about dinosaurs? Their awesome names. It's so fun to learn all of them. So Kobe, what are some of your favorite dinosaur names?
KOBE: Melissa, Keith, Kevin, and Susan.
MOLLY BLOOM: Yes, I like those names too. But I was thinking more like the types of dinosaurs like Stegosaurus. But, yes, I definitely like those names. Well, we have a little game for you about dino names. It's called Guess-o-saurus Rex. Ready to play?
KOBE: Yeah, sure.
MOLLY BLOOM: All right, here we go. First question, the triceratops was an herbivore living in North America over 65 million years ago. So why is it called triceratops? A, the dinosaur was discovered by paleontologist Sarah Tops. B, it's named for the three horns on its head. Or C, it's named after its favorite plant to snack on. So is it, A, discovered by Sarah Tops, B, named for the three horns on its head, or, C, named after its favorite plant snack on?
KOBE: I think it's B, it has three horns on its head.
MOLLY BLOOM: You are correct. The answer is, in fact, B. Triceratops comes from Greek "tri" means three, "cera" means horn, and "tops" means face, so three-horned face. All right, here's question number two. Skorpiovenator lived in the Cretaceous in South America. Its nearly complete skeleton was discovered in 2008.
Its super cool name, Skorpiovenator, comes from A, the fact that the dinosaur resembles a scorpion, B, its Zodiac sign is Scorpio with Scorpio rising, or, C, there were a lot of scorpions hanging out at the dig site where it was found? So is it, A, resembles a scorpion, B, Zodiac sign is Scorpio, or, C, there were lots of scorpions hanging out at the dig site?
KOBE: I think-- is it C?
MOLLY BLOOM: You are correct. It is C. When they found this dinosaur, there were a lot of scorpions there. So they named it Skorpiovenator after all the scorpions at the site.
All right, the third and final question, the velociraptor was made famous in Jurassic Park and Jurassic World. It's relatively small, but has amazing claws and sharp teeth. So where does the name velociraptor come from? Is it, A, its name means speedy thief after the fact it could probably run up to 40 miles per hour, B, it had wings resembling a hawk's, or, C, it was known as being the best rapper in the Late Cretaceous and was actually found near a fossilized microphone? So was it, A, speedy thief, B, wings like a hawk, or, C, super cool rapper?
KOBE: I'm pretty sure it's not C.
MOLLY BLOOM: I think you're right. Yeah, good process of elimination. I like it.
KOBE: And so I'm pretty sure it's A.
MOLLY BLOOM: You are correct. It is A. Yeah, "veloci" means fast and "raptor" means thief. So it's a speedy little thief. Nice work, Kobe. You are three for three, dino pro.
KOBE: Yeah, yeah.
MOLLY BLOOM: So velociraptor was super speedy. But how do scientists know that?
KOBE: How do we know how dinosaurs moved around if all we have is their bones?
MOLLY BLOOM: Brains On dino correspondent David Jah looked into that for us.
DAVID JAH: OK, so if you've ever been to a natural history museum, you've probably seen a dinosaur skeleton fully reassembled. And because scientists have put the bones back in order, you might think they agree on how dinosaurs stood, how they walked, and how they moved, but not quite. In the 1800s when paleontologists first started studying what few dinosaur fossils they possessed, they had very different ideas about how these animals lived. To explain, here's 21st century paleontologist Jingmai O'Connor.
JINGMAI O'CONNOR: So at that time, scientists thought that sauropods, these huge herbivorous land dinosaurs with really long necks, they thought that they were carnivorous and lived in water.
DAVID JAH: Today, we know that sauropods were, in fact, plant-eating animals that lived on land, almost like a dinosaur version of a giant giraffe. So why did early paleontologists have such a different idea?
JINGMAI O'CONNOR: They maybe only had a certain part of the skeleton available to them. Or they couldn't conceive that such large animals would be capable of living on land.
DAVID JAH: Back then, there was much less data to work with. We hadn't found as many fossils as we have now. So for the most part, we used our imagination.
But our imaginations aren't always correct. Sometimes they can be very wrong. One great example of this has to do with the most famous carnivore of all, Tyrannosaurus Rex.
Because T-Rex had two legs, early paleontologists simply thought that it stood upright with its back straight, dragging its tail on the ground. It wasn't until the 1970s that paleontologists started to rethink the way a T-Rex carried itself. By observing the way modern birds walked, paleontologists realized, it made much more sense that T-Rex actually walked hunched over, like a giant chicken with a tail.
[SQUAWKING]
Turns out, Tyrannosaurus skeletons had been displayed incorrectly in museums for years. It might not be as noble to imagine the T-Rex waddling like a giant chicken, but, hey, that's science. In fact, studying modern animals is a big help to paleontologists trying to understand dinosaur body structure. Here's Jingmai O'Connor again.
JINGMAI O'CONNOR: Paleontologists will do dissections of living animals. And they will study where all the different muscles are attaching. And they'll be able to say, oh, OK, this muscle would have been small or this muscle would have been big. And these are all these hundreds and hundreds of little clues that then help you understand how an animal would have held up-- what its posture would have been like.
JINGMAI O'CONNOR: One creature that scientists are still trying to figure out is called Microraptor. Microraptor was small, about two pounds and 2 and 1/2 feet long. It was a flying dinosaur and it had wings on its front legs and wings on its hind legs. Four wings is better than two, if you ask me.
JINGMAI O'CONNOR: We don't really know how it flew exactly. So some people think that its legs would have been sticking out the same way a bird's wings stick out, right? But then people argue that based on the hips structure, that that was not physically possible, you know, basically, for this dinosaur to do the splits, that if you were to do that, then the hip would dislocate itself.
DAVID JAH: At the end of the day, paleontologists have to do the best they can with what they have. It's really hard to know for sure what a dino looked like when you don't have the complete picture.
JINGMAI O'CONNOR: Of all life that ever lived, the fossil record only records a fraction of it. And then we have only access to a fraction of that fossil record through our excavations. So we're always increasing the fossil record. Every summer, there are hundreds of paleontologists all around the world who go out and dig up new fossils and show us new animals and show us a more complete picture. But the picture is always incomplete.
DAVID JAH: And there are things we may never know.
JINGMAI O'CONNOR: Say you have one fossil organism. Like, say you take T-Rex. And we have T-Rexes that are almost complete. But it's only the bones that you have.
You're missing all the other soft tissues, the organs. You don't know what kind of sounds they made. There's so much information that we don't have because these animals are extinct, right?
DAVID JAH: What does all this mean?
JINGMAI O'CONNOR: Of course, it's very likely that a majority of what we think we in paleontology is actually wrong. And we will learn that we are wrong once we find new fossils.
DAVID JAH: If you're a young dino enthusiast or an aspiring paleontologist, that might sound a little discouraging. But that's actually what makes studying dinosaurs so exciting. We're constantly updating our knowledge of how these creatures lived. There's always more to know.
JINGMAI O'CONNOR: Paleontology is constantly in flux. Science is based on mistakes, not just paleontology. Because you are gathering data. And with the data that you have, you make a hypothesis.
And when new data becomes available, very often, the earlier hypothesis, based on less data, turns out to be wrong. So if you want to be a scientist, you really have to be able to say, I was wrong. And there's absolutely no shame on that.
DAVID JAH: Dinosaurs might be millions of years old, but that doesn't mean we know everything about them. Even after all this time, we're still learning new things about these ancient animals.
MOLLY BLOOM: Thanks, David.
DAVID JAH: Absolutely.
KOBE: Bye.
[MUSIC PLAYING]
MOLLY BLOOM: We don't know exactly how T-Rex sounded.
KOBE: But it might have been deep and grunty like a crocodile.
MOLLY BLOOM: For other dinos, skull and evidence of soft tissue can help us imagine what sounds they made.
KOBE: Figuring out how dinosaurs moved is a bigger puzzle than you might think.
MOLLY BLOOM: So paleontologists study fossils really, really closely.
KOBE: They also compare dinosaurs to living animals.
MOLLY BLOOM: And they learn new things all the time. That's it for this episode of Brains On.
KOBE: It was produced by Menaka Wilhelm, Marc Sanchez, Sanden Totten, and Molly Bloom.
MOLLY BLOOM: We had production help from Kristina Lopez and David Zha, engineering help from Eric Romani. Special thanks to Scott Hartman, Mark [? Tune, ?] Taylor Smith Productions, and the Cornell Lab of Ornithology.
KOBE: Now, before we go, it's time for our Moment of Um.
[AUDIO LOGO] Um, um, um, um, um, um, um.
SAMEERA: My question is, how does hair dye work?
MICHELLE WONG: So I've dyed my hair a lot of times. I've dyed it with permanent hair color, as well as with temporary hair color. At the moment, I actually have purple hair.
Hi my name is Dr. Michelle Wong. I did a PhD in chemistry at the University of Sydney in Australia. First, let's talk about why hair dye is colored. So, the way that colored molecules work is they absorb particular colors of light.
And so when white light hits it, it absorbs blue, let's say. And then it reflects the opposite color. So something that absorbs blue will look orange.
There are two kinds of hair dye-- temporary and permanent. Temporary hair dye has colored molecules that stick to the outside of your hair. So that means it doesn't last for very long. The molecules get washed away every time you shampoo your hair. And so the color ends up fading away.
There's also permanent hair dye. With permanent hair dye molecules, these ones usually come as little molecules that aren't the final color yet. So most of the time, they're colorless. And then after they've gotten into your hair and react to form a bigger molecule, then it becomes colored.
You can think of hair like a really long cage. The small molecules can get inside the hair. Then they join together to form a much bigger colored molecule. And it's too big to get out of the cage very easily. So unlike the temporary color that was stuck to the outside of the cage, the permanent hair dye is trapped inside the cage. And so it doesn't wash away.
There's also hair bleach, which makes your hair white. Dark hair naturally has melanin in it, which is a colored chemical. And bleach breaks up the melanin into smaller molecules that don't absorb any light. And so that means that your hair looks white. It's sort of like the opposite of the permanent hair dye reaction.
When you have really fun colors like purple or blue or pink or green, a lot of the time, this is actually temporary hair color. So you'll have to have bleached hair first. So I went to a hairdresser and got my hair bleached to white. And then you can dye these fun colors on top.
[AUDIO LOGO] Um, um.
MOLLY BLOOM: I bet you've been dying to hear this list of names. It's time for the Brains Honor Roll. These are the incredible listeners who share their questions, ideas, mystery sounds, drawings, and high fives with us--
[LISTING HONOR ROLL]
Brains On will be back soon with more answers to your questions.
KOBE: Thanks for listening.
SUBJECT: Brains On is supported in part by a grant from the National Science Foundation.
[GROWLING AND STOMPING]
[MMM]
[HOWLING]
SANDEN TOTTEN: Hey Molly and Kobe.
MOLLY BLOOM: Hey, what are you up to Sanden?
KOBE: Imitating a petting zoo?
MOLLY BLOOM: Or activating your voice commands for Harvey?
SANDEN TOTTEN: Close, we're practicing the noises we think dinosaurs might have made.
[GROWLING AND STOMPING]
KOBE: I like the stomping.
SANDEN TOTTEN: Molly, do you have a dino impression? MOLLY BLOOM: Hm, yeah. [POOT] [LAUGHTER] A toot, that's probably a plant-eating dinosaur.
SANDEN TOTTEN: Don't you think dino farts would be bigger? I think it'd be more like--
[LONG FART]
What about you, Kobe, what do you think dinosaurs might have sounded like?
KOBE: Well, what if T-Rex actually sounded like meow?
[MEOWING]
MOLLY BLOOM: You're listening to Brains On from American Public Media. I'm Molly Bloom. And my co-host today is Kobe from San Mateo, California. Hi, Kobe.
KOBE: Hi.
MOLLY BLOOM: Kobe, you wrote to us with a really great question about dinosaurs.
KOBE: How do scientists know what sounds dinosaurs used to make? What if T-Rex actually made really cute sounds like a kitten?
MOLLY BLOOM: So Kobe, how did you think of that question? How did it pop in your head?
KOBE: Oh, I think I was watching a documentary on dinosaurs. And I thought, is that really what they sound like?
MOLLY BLOOM: So what kind of sounds do you imagine other dinosaurs making?
KOBE: Maybe they made sounds kind of like a bear or a-- like a tiger or a lion.
MOLLY BLOOM: So a little more fierce than a kitten, perhaps?
KOBE: Yeah.
MOLLY BLOOM: So this is our second episode all about what dinosaurs were really like. In the first episode, we took a look at dinosaur colors.
KOBE: Plus, if dinos tooted. Definitely check it out.
MOLLY BLOOM: This time, we're taking a look at other parts of dinosaurs' lives.
KOBE: How they might have sounded.
MOLLY BLOOM: And how they stood and moved.
KOBE: Dinosaur fossils give us clues about these things.
MOLLY BLOOM: But if you think about how we talk and move, we use our vocal cords to sing and shout and our muscles to move.
KOBE: It's squishy body parts that do those things, not bones.
MOLLY BLOOM: And squishy body parts, which are also called soft tissue, they don't show up well in fossils.
KOBE: They break down too quickly.
MOLLY BLOOM: Hard body parts fossilize better.
KOBE: Mostly that's bones and teeth.
MOLLY BLOOM: But, lately, scientists have found little bits of soft tissue, along with dinosaur bones, footprints, and poop.
KOBE: Paleontologists have to dig very carefully to find those fossils.
MOLLY BLOOM: And then they study them very closely. They take special 3D x-rays of bones to understand their exact shape inside and out.
KOBE: That helps them think about how all kinds of body parts fit together.
MOLLY BLOOM: They also use powerful microscopes to zoom way in on fossils' tiniest details.
KOBE: That can sometimes show how strong the bones were, which helps you think about how big a dino was and how it moved.
MOLLY BLOOM: And they often compare dinosaurs to living animals too.
KOBE: With all these clues, we can start to come up with ideas about how a long gone animal might have lived.
MOLLY BLOOM: Which brings us to your question about T-Rex sounds, Kobe. When you wrote in, you pointed out that sounds don't show up in the fossil record, which is totally true. So we got in touch with someone who has thought about what Tyrannosaurus Rex might have sounded like.
JULIA CLARKE: My name is Julia Clarke. And I'm a professor of paleontology at the University of Texas at Austin.
MOLLY BLOOM: Julia said, the first thing to think about if you want to imagine what an extinct animal might have sounded like is how big it was.
JULIA CLARKE: One of the things we know about animals is that larger animals generally have deeper voices. They make lower frequency sounds. And small animals tend to make higher frequency sounds, in general. You know, there are rule breakers to everything.
MOLLY BLOOM: So if T-Rex made noises, it would probably have made lower, deeper sounds. But how do we know T-Rex made sounds at all?
KOBE: What if it was more of a silent thinker?
MOLLY BLOOM: Well, Julia looked at T-Rex's closest living relatives.
JULIA CLARKE: So those are crocodilians, alligators and crocodiles and their relatives, and living birds. We can look at both of those groups. And in both of those groups, they're pretty noisy compared to other reptiles.
MOLLY BLOOM: So there's a good chance T-Rex did make sounds. And check out these alligator sounds. These are American alligators, the ones that live in North America.
[DEEP BELLOW]
[GROWL]
And what's really cool is that all of those sounds are made with the mouth closed.
KOBE: Closing your mouth really changes how sound comes out.
MOLLY BLOOM: You can say that again.
[HMM HMM HMM HMM]
So when Julia and her team put together a sound that might have been what T-Rex sounded like, here's what they did.
JULIA CLARKE: We took crocodile sounds and closed mouth vocalizing and open mouth vocalizing birds. And then we basically remixed the frequency of those sounds into the range of something similar to the size of an animal of T-Rex.
MOLLY BLOOM: Now, this is a very deep and low sound. So listen closely.
[DEEP STATIC SOUND]
Kobe, what do you think of that sound? Do you think that's what a T-Rex sounds like?
KOBE: Yeah it sounds a lot like static, like a very low static.
MOLLY BLOOM: Yeah, to me, it kind of sounds like what I imagine it would sound like if they were like stomping on the ground far away from me.
[AUDIO LOGO] Brains, brains, brains on.
MOLLY BLOOM: For some dinosaurs like T-Rex, thinking about their sounds is like a fun thought experiment. For other dinosaurs, fossils do have information about their sounds. We asked Riley Black to fill us in on that. She writes all about dinosaurs.
KOBE: Hi, Riley.
RILEY BLACK: Hi, Kobe.
KOBE: How are you doing?
RILEY BLACK: I'm doing OK. I hear you have a lot of dinosaur questions for me.
KOBE: Oh yeah, the first one is, what kind of fossils can tell us about dinosaur sounds?
RILEY BLACK: Well, that's a really neat question because the fact is that lots of different kinds of fossils can tell us about that. I was thinking a little bit about that question the other day. Because we think about dinosaur noises a lot. Did they roar? Did they scream? Did they honk?
But dinosaurs could actually make lots of different kinds of sounds. We look at animals today, like alligators and stuff. Sometimes they clap their jaws. Or lizards, they rub their scales together to make noise. So there are really lots of different ways that dinosaurs could have made noise or communicated with each other. But when we talk about sounds, kind of like dinosaur voices in a way, those fossils are actually really, really super duper rare.
KOBE: What can scientists reconstruct about these sounds?
RILEY BLACK: There are a few dinosaurs that we have where they have these really neat crests. So you know like hadrosaurs, right, like duckbill dinosaurs. Have you heard of those before.
KOBE: Oh, yeah.
RILEY BLACK: Some of those dinosaurs-- like, there's one from my home state here in Utah called Paracelsus. And that's what this long kind of tube, like a big piece of pipe almost coming off the back of its head. And there's a few relatives like Corythosaurus and Lambeosaurus that they have neat headgear too. And those crests are hollow.
And if you look inside of those, there's a tube on the inside that connects from their nose all through that crest all the way to the back of their throat. And we can figure out through computer models how the air would have moved through those. And we figured that they would have made these really deep honking kind of sounds. So not quite like a duck, but have you ever heard like an elephant, like those low kind of rumbly sounds? Those are the sorts of sounds that these dinosaurs probably made.
KOBE: Oh, that's really cool.
MOLLY BLOOM: So we just listened to Dr. Julia Clarke's reconstruction of what a T-Rex might sound like. And I know she's also studied bird fossils of something called a syrinx. But the syrinx, it's not-- it's not quite a bone, right?
RILEY BLACK: Yeah, so syrinx is made of cartilage. That's the same stuff that's in the tip of your nose and in your ears. It's really flexible. So we usually don't see a whole lot of them in the fossil record.
It's super duper rare that Dr. Clarke was able to find one. And the fact that it was in this bird indicates that this particular organ that allows birds to kind of make a lot of complex sounds, like some of the singing sounds and a lot of the neat things that we think of when we think of birds, it happened relatively late in their evolution. So dinosaurs before that time probably sounded a bit more like alligators and crocodiles and stuff today.
They can probably grumble and they can make these kind of like really low sounds. But they probably weren't doing really complex stuff like a cardinal singing or something like that. So that's what we're really hoping to find more of, are more of these what we call soft tissues, the interior stuff that can tell us sort of what the throat and the airway of these dinosaurs were like.
KOBE: What parts of dinosaur sounds will probably stay mysteries?
RILEY BLACK: Well, one of the neat things about dinosaurs is that we're never going to find all of them. It's kind of sad, but it's also kind of neat that-- because it really highlights how awesome it is that we found so many already. Dinosaurs in the ancient past, we only get their fossils in environments where new sediment like sand or ash or mud or silt were being laid down-- so places like floodplains or the edges of lakes and things like that. Dinosaurs that lived in the mountains, those environments weren't preserved.
So we're never going to know about those dinosaurs and maybe what sounds they made. And there are some dinosaurs that if we have, for example, like a leg bone. And some dinosaurs are only known from a leg bone or for some other part of their skeleton. We may never have the information to find out what that specific species sounded like.
And we know that's important. Because when we look at animals today, even closely related animals can make very, very different sounds. So there's always going to be a place for imagination, for thinking about, well, what could they have possibly sounded like?
And I think that's really, really neat. Because if we had all the answers, it could just be like an encyclopedia. It's the stuff that we don't know that keeps us going back to the fossil record.
KOBE: That's very interesting.
RILEY BLACK: Yeah, this is really the best time in history so far in the history of paleontology to be a dinosaur fan. Not only are we finding more just an incredible rate-- like a new species of dinosaur is named every two weeks. But the technology that we have now to scan these fossils, to understand their chemistry and their anatomy and all that stuff, it's way different than it was 100 years ago, even 20 years ago.
So now if you find a dinosaur fossil, you can tell so much about how that animal lived. And that's really cool. And that's why I'm glad we've been talking about dinosaur sounds. Because fossils are typically very quiet. So it's really fun to imagine what sounds there would have been and then like what evidence would we use to come up with that.
KOBE: Thank you, Riley.
RILEY BLACK: Oh, this was so much fun. Have a good day, Kobe.
[AUDIO LOGO] Brains on, on, on.
MOLLY BLOOM: Here is a sound that is definitely real and not reconstructed. It's time for the--
[WHOOSH]
[DING]
[MUSIC PLAYING] Mystery sound.
MOLLY BLOOM: Here it is.
[SQUEAKING AND CHIRPING]
What is your guess?
KOBE: It sounds kind of like a bunch of electronics, like somebody is fixing something in a jungle maybe. I heard some birds in the background.
MOLLY BLOOM: So we heard some electronics, maybe some birds. Well, we'll hear it again and give you another chance to guess a little bit later in the show.
[MUSIC PLAYING]
We're working on an episode all about time travel and we want to know when you would go in time if you could-- the past, the future. Kobe, when would you want to travel to?
KOBE: I would probably want to travel to the near future so I can do all the things I can't do now because of COVID.
MOLLY BLOOM: I think a lot of our audience feels the same. Well, send your answers to us at brainson.org/contact.
KOBE: And your answer could be part of the episode.
MOLLY BLOOM: Like this question.
SAMEERA: My name is Sameera. And I'm from Philadelphia. And my question is, how does hair dye work?
KOBE: We'll answer that in the Moment of Um at the end of the show.
MOLLY BLOOM: And read the latest additions to the Brains Honor Roll. They're the brilliant listeners that send us their questions, ideas, drawings, and mystery sounds.
KOBE: Send in yours at brainson.org/contact.
MOLLY BLOOM: We love reading and listening to everything you send in.
KOBE: Keep listening.
MOLLY BLOOM: You're listening to Brains On from American Public Media. I'm Molly.
KOBE: I'm Kobe.
MOLLY BLOOM: And this is the mystery sound again.
[SQUEAKING AND CHIRPING]
All right, so last time you heard electronics or maybe birds. What thought do you have now?
KOBE: Maybe like in a lab. I heard like it sounded like there were some like baby birds maybe.
MOLLY BLOOM: OK, well, let's hear the answer.
ZANDER CORBETT: Hi, I'm Zander Corbett. I live in New Zealand. That was the sound of a tui near my house. They only live in New Zealand. And they have two voice boxes at the end.
MOLLY BLOOM: So a tui is indeed a kind of bird. So you were correct. Those were birds.
KOBE: Nice. That didn't sound a lot like any bird I've heard before.
MOLLY BLOOM: Yeah, well, those are birds that are only found in New Zealand. So unless you live in New Zealand, that would not be a familiar bird sound.
[AUDIO LOGO] Ba-ba-ba-ba-ba-ba-ba-ba-ba-ba brains on.
MOLLY BLOOM: You know what's one of my favorite things about dinosaurs? Their awesome names. It's so fun to learn all of them. So Kobe, what are some of your favorite dinosaur names?
KOBE: Melissa, Keith, Kevin, and Susan.
MOLLY BLOOM: Yes, I like those names too. But I was thinking more like the types of dinosaurs like Stegosaurus. But, yes, I definitely like those names. Well, we have a little game for you about dino names. It's called Guess-o-saurus Rex. Ready to play?
KOBE: Yeah, sure.
MOLLY BLOOM: All right, here we go. First question, the triceratops was an herbivore living in North America over 65 million years ago. So why is it called triceratops? A, the dinosaur was discovered by paleontologist Sarah Tops. B, it's named for the three horns on its head. Or C, it's named after its favorite plant to snack on. So is it, A, discovered by Sarah Tops, B, named for the three horns on its head, or, C, named after its favorite plant snack on?
KOBE: I think it's B, it has three horns on its head.
MOLLY BLOOM: You are correct. The answer is, in fact, B. Triceratops comes from Greek "tri" means three, "cera" means horn, and "tops" means face, so three-horned face. All right, here's question number two. Skorpiovenator lived in the Cretaceous in South America. Its nearly complete skeleton was discovered in 2008.
Its super cool name, Skorpiovenator, comes from A, the fact that the dinosaur resembles a scorpion, B, its Zodiac sign is Scorpio with Scorpio rising, or, C, there were a lot of scorpions hanging out at the dig site where it was found? So is it, A, resembles a scorpion, B, Zodiac sign is Scorpio, or, C, there were lots of scorpions hanging out at the dig site?
KOBE: I think-- is it C?
MOLLY BLOOM: You are correct. It is C. When they found this dinosaur, there were a lot of scorpions there. So they named it Skorpiovenator after all the scorpions at the site.
All right, the third and final question, the velociraptor was made famous in Jurassic Park and Jurassic World. It's relatively small, but has amazing claws and sharp teeth. So where does the name velociraptor come from? Is it, A, its name means speedy thief after the fact it could probably run up to 40 miles per hour, B, it had wings resembling a hawk's, or, C, it was known as being the best rapper in the Late Cretaceous and was actually found near a fossilized microphone? So was it, A, speedy thief, B, wings like a hawk, or, C, super cool rapper?
KOBE: I'm pretty sure it's not C.
MOLLY BLOOM: I think you're right. Yeah, good process of elimination. I like it.
KOBE: And so I'm pretty sure it's A.
MOLLY BLOOM: You are correct. It is A. Yeah, "veloci" means fast and "raptor" means thief. So it's a speedy little thief. Nice work, Kobe. You are three for three, dino pro.
KOBE: Yeah, yeah.
MOLLY BLOOM: So velociraptor was super speedy. But how do scientists know that?
KOBE: How do we know how dinosaurs moved around if all we have is their bones?
MOLLY BLOOM: Brains On dino correspondent David Jah looked into that for us.
DAVID JAH: OK, so if you've ever been to a natural history museum, you've probably seen a dinosaur skeleton fully reassembled. And because scientists have put the bones back in order, you might think they agree on how dinosaurs stood, how they walked, and how they moved, but not quite. In the 1800s when paleontologists first started studying what few dinosaur fossils they possessed, they had very different ideas about how these animals lived. To explain, here's 21st century paleontologist Jingmai O'Connor.
JINGMAI O'CONNOR: So at that time, scientists thought that sauropods, these huge herbivorous land dinosaurs with really long necks, they thought that they were carnivorous and lived in water.
DAVID JAH: Today, we know that sauropods were, in fact, plant-eating animals that lived on land, almost like a dinosaur version of a giant giraffe. So why did early paleontologists have such a different idea?
JINGMAI O'CONNOR: They maybe only had a certain part of the skeleton available to them. Or they couldn't conceive that such large animals would be capable of living on land.
DAVID JAH: Back then, there was much less data to work with. We hadn't found as many fossils as we have now. So for the most part, we used our imagination.
But our imaginations aren't always correct. Sometimes they can be very wrong. One great example of this has to do with the most famous carnivore of all, Tyrannosaurus Rex.
Because T-Rex had two legs, early paleontologists simply thought that it stood upright with its back straight, dragging its tail on the ground. It wasn't until the 1970s that paleontologists started to rethink the way a T-Rex carried itself. By observing the way modern birds walked, paleontologists realized, it made much more sense that T-Rex actually walked hunched over, like a giant chicken with a tail.
[SQUAWKING]
Turns out, Tyrannosaurus skeletons had been displayed incorrectly in museums for years. It might not be as noble to imagine the T-Rex waddling like a giant chicken, but, hey, that's science. In fact, studying modern animals is a big help to paleontologists trying to understand dinosaur body structure. Here's Jingmai O'Connor again.
JINGMAI O'CONNOR: Paleontologists will do dissections of living animals. And they will study where all the different muscles are attaching. And they'll be able to say, oh, OK, this muscle would have been small or this muscle would have been big. And these are all these hundreds and hundreds of little clues that then help you understand how an animal would have held up-- what its posture would have been like.
JINGMAI O'CONNOR: One creature that scientists are still trying to figure out is called Microraptor. Microraptor was small, about two pounds and 2 and 1/2 feet long. It was a flying dinosaur and it had wings on its front legs and wings on its hind legs. Four wings is better than two, if you ask me.
JINGMAI O'CONNOR: We don't really know how it flew exactly. So some people think that its legs would have been sticking out the same way a bird's wings stick out, right? But then people argue that based on the hips structure, that that was not physically possible, you know, basically, for this dinosaur to do the splits, that if you were to do that, then the hip would dislocate itself.
DAVID JAH: At the end of the day, paleontologists have to do the best they can with what they have. It's really hard to know for sure what a dino looked like when you don't have the complete picture.
JINGMAI O'CONNOR: Of all life that ever lived, the fossil record only records a fraction of it. And then we have only access to a fraction of that fossil record through our excavations. So we're always increasing the fossil record. Every summer, there are hundreds of paleontologists all around the world who go out and dig up new fossils and show us new animals and show us a more complete picture. But the picture is always incomplete.
DAVID JAH: And there are things we may never know.
JINGMAI O'CONNOR: Say you have one fossil organism. Like, say you take T-Rex. And we have T-Rexes that are almost complete. But it's only the bones that you have.
You're missing all the other soft tissues, the organs. You don't know what kind of sounds they made. There's so much information that we don't have because these animals are extinct, right?
DAVID JAH: What does all this mean?
JINGMAI O'CONNOR: Of course, it's very likely that a majority of what we think we in paleontology is actually wrong. And we will learn that we are wrong once we find new fossils.
DAVID JAH: If you're a young dino enthusiast or an aspiring paleontologist, that might sound a little discouraging. But that's actually what makes studying dinosaurs so exciting. We're constantly updating our knowledge of how these creatures lived. There's always more to know.
JINGMAI O'CONNOR: Paleontology is constantly in flux. Science is based on mistakes, not just paleontology. Because you are gathering data. And with the data that you have, you make a hypothesis.
And when new data becomes available, very often, the earlier hypothesis, based on less data, turns out to be wrong. So if you want to be a scientist, you really have to be able to say, I was wrong. And there's absolutely no shame on that.
DAVID JAH: Dinosaurs might be millions of years old, but that doesn't mean we know everything about them. Even after all this time, we're still learning new things about these ancient animals.
MOLLY BLOOM: Thanks, David.
DAVID JAH: Absolutely.
KOBE: Bye.
[MUSIC PLAYING]
MOLLY BLOOM: We don't know exactly how T-Rex sounded.
KOBE: But it might have been deep and grunty like a crocodile.
MOLLY BLOOM: For other dinos, skull and evidence of soft tissue can help us imagine what sounds they made.
KOBE: Figuring out how dinosaurs moved is a bigger puzzle than you might think.
MOLLY BLOOM: So paleontologists study fossils really, really closely.
KOBE: They also compare dinosaurs to living animals.
MOLLY BLOOM: And they learn new things all the time. That's it for this episode of Brains On.
KOBE: It was produced by Menaka Wilhelm, Marc Sanchez, Sanden Totten, and Molly Bloom.
MOLLY BLOOM: We had production help from Kristina Lopez and David Zha, engineering help from Eric Romani. Special thanks to Scott Hartman, Mark [? Tune, ?] Taylor Smith Productions, and the Cornell Lab of Ornithology.
KOBE: Now, before we go, it's time for our Moment of Um.
[AUDIO LOGO] Um, um, um, um, um, um, um.
SAMEERA: My question is, how does hair dye work?
MICHELLE WONG: So I've dyed my hair a lot of times. I've dyed it with permanent hair color, as well as with temporary hair color. At the moment, I actually have purple hair.
Hi my name is Dr. Michelle Wong. I did a PhD in chemistry at the University of Sydney in Australia. First, let's talk about why hair dye is colored. So, the way that colored molecules work is they absorb particular colors of light.
And so when white light hits it, it absorbs blue, let's say. And then it reflects the opposite color. So something that absorbs blue will look orange.
There are two kinds of hair dye-- temporary and permanent. Temporary hair dye has colored molecules that stick to the outside of your hair. So that means it doesn't last for very long. The molecules get washed away every time you shampoo your hair. And so the color ends up fading away.
There's also permanent hair dye. With permanent hair dye molecules, these ones usually come as little molecules that aren't the final color yet. So most of the time, they're colorless. And then after they've gotten into your hair and react to form a bigger molecule, then it becomes colored.
You can think of hair like a really long cage. The small molecules can get inside the hair. Then they join together to form a much bigger colored molecule. And it's too big to get out of the cage very easily. So unlike the temporary color that was stuck to the outside of the cage, the permanent hair dye is trapped inside the cage. And so it doesn't wash away.
There's also hair bleach, which makes your hair white. Dark hair naturally has melanin in it, which is a colored chemical. And bleach breaks up the melanin into smaller molecules that don't absorb any light. And so that means that your hair looks white. It's sort of like the opposite of the permanent hair dye reaction.
When you have really fun colors like purple or blue or pink or green, a lot of the time, this is actually temporary hair color. So you'll have to have bleached hair first. So I went to a hairdresser and got my hair bleached to white. And then you can dye these fun colors on top.
[AUDIO LOGO] Um, um.
MOLLY BLOOM: I bet you've been dying to hear this list of names. It's time for the Brains Honor Roll. These are the incredible listeners who share their questions, ideas, mystery sounds, drawings, and high fives with us--
[LISTING HONOR ROLL]
Brains On will be back soon with more answers to your questions.
KOBE: Thanks for listening.
Transcription services provided by 3Play Media.
