Dr. Dave Hone on Lex Fridman: Why T-Rex Never Actually Ran

1. 0:00 – 1:23

   Episode highlight

   1. DHDave Hone0:00

      ... T-rex is definitely weird, even compared to all the other giant tyrannosaurs that are very closely related to it, because it is by far, ludicrously by far, the largest carnivore in its ecosystem.

   2. LFLex Fridman0:14

      So it doesn't really have competition, actually.

   3. DHDave Hone0:16

      I mean, so, so this is a velociraptor skull. There are some carnivores that are a bit bigger than this, but not enormously so, um, which we're knocking around as T-rex. The, the skull's the same type-

   4. LFLex Fridman0:30

      (laughs)

   5. DHDave Hone0:30

      ... toothed crap. Right. But, but, like, you think about that-

   6. LFLex Fridman0:33

      Yeah.

   7. DHDave Hone0:33

      ... and that's like going, go- that's like going to Africa and going, "Okay, there are lions. What's the next biggest predator?" And it's like, "Well, there's a weasel about this big."

   8. LFLex Fridman0:44

      Yeah.

   9. DHDave Hone0:44

      Like, it, it's that kinda size difference, and you don't get that normally in ecosystems.

   10. LFLex Fridman0:51

       It would eat those, the juvenile of the herbivores, but not-

   11. DHDave Hone0:54

       Oh yeah, it's gonna be eating triceratops and edmontosaurus and parasaurolophus. There's even a couple of giant sauropods-

   12. LFLex Fridman0:58

       Got it.

   13. DHDave Hone0:58

       ... knocking around in some places. It's, it's gonna be hoovering them up, but, like, how often is it gonna eat... Again, velociraptor isn't there. But how often is it gonna eat something the size of an adult velociraptor?

   14. LFLex Fridman1:08

       Yeah.

   15. DHDave Hone1:09

       I mean, they're a fraction of our size, and we're probably too small. Th- this is like lions hunting mice. Like, you're just not gonna bo- unless one, like, virtually runs into your mouth, (laughs) you're not gonna go and try and eat it.

2. 1:23 – 1:56

   Introduction

   1. LFLex Fridman1:23

      The following is a conversation with Dave Hone, a paleontologist, expert on dinosaurs, co-host of the Terrible Lizards podcast, and author of many scientific papers and books on the behavior and ecology of dinosaurs. This was truly a fun and fascinating conversation. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description and consider subscribing to this channel. And now, dear friends, here's Dave Hone.

3. 1:56 – 25:38

   T-Rex's size & biomechanics

   1. LFLex Fridman1:56

      Let's start with the T-rex dinosaur, possibly the most iconic predator in the history of Earth. You have deeply studied and written about their evolution, biology, ecology, and behavior, so let's, uh, first maybe put ourselves in the time of the dinosaurs and imagine we're standing in front of a T-rex. What does it look like? What are the key features of the dinosaur in front of us?

   2. DHDave Hone2:18

      It's gigantic. It's almost trite now because everyone knows T-rex is massive. But yes, if you actually stand in front of one, you would be seriously impressed just how absolutely vast they are. Um, so I've got a copy of a T-rex skull (laughs) in my, downstairs from my office. And yeah, I, I could fit comfortably through its mouth. So it would be just about capable of swallowing me whole, and I'm a pretty big guy.

   3. LFLex Fridman2:44

      Your body, you can fit-

   4. DHDave Hone2:46

      Yeah, yeah.

   5. LFLex Fridman2:46

      ... in its mouth?

   6. DHDave Hone2:47

      I can fit through, I can fit through it.

   7. LFLex Fridman2:47

      Wow.

   8. DHDave Hone2:48

      Yeah, yeah, yeah. And it's not even a particularly big one. It's a copy of the one that's in the Smithsonian. And they get bigger than that.

   9. LFLex Fridman2:54

      You have a to-scale copy-

   10. DHDave Hone2:56

       Yeah, yeah.

   11. LFLex Fridman2:57

       ... of one. (laughs)

   12. DHDave Hone2:58

       Yeah, it's a, it's a cast, so it's just a giant mold made and then-

   13. LFLex Fridman3:01

       Nice.

   14. DHDave Hone3:02

       ... pulled out like the dentist do your teeth, but very, very big. So yeah, they are 12-ish meters long, so what's that? 14 yards. Four and a half, maybe five for the top of the head standing up, so another six yards high, and then seven-ish metric tons, what's that? About eight and a half short tons. So a colleague of mine, Tom Holtz, described them as an orca on land. That, that's it. It is a killer whale-sized animal, but on legs, on land. And those are massive (laughs) predators. So you're looking at something absolutely colossal, and I think that is what will stun you. I think people don't realize how big a lot of animals are, which sounds weird. Um, but I used to work in a few zoos, and something I think you notice is when you go and see things like elephants or giraffes or rhinos, everything's built to the scale of the animal. The elephant house is huge. The doors are huge. The bars are huge. The food is huge. And so you don't see them in the context of something that you have a good frame of reference for. And I learnt this, yeah, when I was at London Zoo and w- was, uh, going into the basement of the old elephant and rhino pavilion, and a rhino stuck its head out from like this gap in the wall. And the head was twice the size I thought it was once you stood next to it, and the same with an elephant. I once stood next to an elephant, closer than you are to me now, and you go, "Oh, oh, they are so much bigger (laughs) than I thought." And I think it's similar in museums. Like, even when you get up relatively close to a T-rex skeleton, there's a bit of space between you and it and then some bars and then it's usually raised up a little bit on a mountain, on a little mount to hold the platform, and then you stand back from that, and you don't actually get to stand, like, under them. And when you do that, (laughs) yeah, you realize that, yeah, the, the foot finishes at my knee.

   15. LFLex Fridman4:58

       So is a T-rex bigger than an elephant?

   16. DHDave Hone5:00

       Yeah.

   17. LFLex Fridman5:00

       That'd be fair to say?

   18. DHDave Hone5:01

       Yeah, I mean, a, a very large savanna African elephant is five to six tons, and we're looking at seven-plus.

   19. LFLex Fridman5:11

       (laughs)

   20. DHDave Hone5:11

       And a biped (laughs) and a carnivore. So yeah, you know, a, a big lion, a big lion is 200 kilos, so 430 pounds. Yeah. (laughs)

   21. LFLex Fridman5:23

       Well, that's what, that's why I mean it's widely considered to be probably the most epic, uh, predator in the history of Earth.

   22. DHDave Hone5:31

       Yeah, I mean, and I think more than that. It's, I think it's one of the most iconic animals, period.

   23. LFLex Fridman5:36

       Yeah.

   24. DHDave Hone5:36

       I mean, if you're, if you're listing things that the average person has heard of, lion, elephant, giraffe, tiger, hippo, rhino, there's a few more, but T-rex is coming somewhere up in that list. Th- that's how prominent it is as an animal. So yeah, it's, it, it's almost inescapable as a paleontologist, and then doubly so for me who works on dinosaurs, and doubly so again 'cause I do work on tyrannosaurs. But yeah, it just dominates-... Conversations.

   25. LFLex Fridman6:05

       Well, some of the other features maybe we can go through.

   26. DHDave Hone6:07

       Yeah, sure.

   27. LFLex Fridman6:07

       So big skull, big head, small hands.

   28. DHDave Hone6:11

       Massive head. Very kind of boxy. It's very robust. Um, big forward-facing eyes. Massive eyes. Massive. Ma- I mean, tennis ball-sized eyes. These things had amazing eyesight. Um, yeah. Giant teeth. There's a cast of a-

   29. LFLex Fridman6:28

       What?

   30. DHDave Hone6:29

       ... Tyrannosaurus rex tooth.
4. 25:38 – 38:45

   T-Rex's hunting strategies

   1. DHDave Hone25:38

      or later.

   2. LFLex Fridman25:39

      So let's zoom out. What did it eat?

   3. DHDave Hone25:42

      I mean, the, you could go for the classic joke of whatever it wanted. But the reality is, um, the relatively big herbivores that are around at the time, it's probably largely leaving them alone because, again, just the classic dynamics of predators, even like, quote, super predators like tyrannosaurs, they're still real animals. If you get injured and you can't hunt, that's probably the end of you. So you don't want to tackle an adult triceratops that weighs the same as you and has meter, meter-and-a-half long horns on its head and is potentially pretty aggressive. Um, and then even the big, uh, so the hadrosaurs, the kind of classic duck-billed dinosaurs, they're not, they're not present with any, like, obvious defenses. They don't have armor, they don't have horns or spikes or anything like this. But they're simply massive. Again, you know, yes, T-rex has got the teeth and the bite, and even if they're a bit rubbish with the claws on the hands, but, like, just grappling another animal which is the same size as it, there's a risk you're gonna get a foot trodden on, that it's gonna get off some kind of body slam or whatever. And then even if you do bring it down, you're never gonna eat it. Like, if you- you bring down an animal that weighs five tons, it's nearly your own mass. You're not g- you're not gonna eat it before it goes rotten. That's a huge amount of kind of, not, like, wasted energy, but you've probably put a lot of effort into this and you're not getting that much reward out. And again, there, there are... Again, there are exceptions. You've got things like lynx are the classic one. Lynx are not very big cats, and yet they'll hunt adult deer that are way bigger than them. Lions hunt things like buffalo, but they're operating in a group so it's a bit of a cheat. So there are some things that do this. But fundamentally, the vast majority of carnivores tackle stuff that's way, way smaller than them. And that's what we see. Um, every record we have of basically any large carnivorous dinosaur where you have stomach contents, whether it's, like, consumed something or healed bite marks, we get quite a, we get a, not f- quite a few, there's a handful of them, where there's an obvious damage to a bone, in more than a couple of cases with a tooth broken off in the bone and then the bone has healed over it, so you know (laughs) it got away, they're, they're juveniles. They're relatively young animals.

   4. LFLex Fridman28:00

      Mm-hmm.

   5. DHDave Hone28:00

      And that's what they're targeting. Um, it makes ecological sense. It's what modern animals do for very good reason. Juveniles are relatively small and weak. They don't have the horns or frills or armor or shields and other stuff. They're naïve. They don't, they have, you often have to learn what predators are or you have to learn how to avoid them or to check the wind or even physically see them before you know, see them kill something else before you know that they're a threat. And juveniles forage badly. Um, they're relatively inefficient, so actually they need to eat more for their size than an adult does. And then on top of that, they're not very experienced at foraging in the right areas. And even if they can find a good patch, the adults will often beat them up and chase them off.

   6. LFLex Fridman28:47

      You're talking about juveniles across various species?

   7. DHDave Hone28:49

      Everything. This is just a universal pattern of being a smaller animal versus a larger, or a younger animal versus a larger animal.

   8. LFLex Fridman28:55

      So, so hunting young, uh-

   9. DHDave Hone28:58

      Young things.

   10. LFLex Fridman28:58

       ... young things is easier.

   11. DHDave Hone29:00

       Yeah, because-

   12. LFLex Fridman29:00

       Because they're dumb.

   13. DHDave Hone29:01

       Right. They're dumb, but they're inexperienced.

   14. LFLex Fridman29:02

       Inexperienced. Yeah.

   15. DHDave Hone29:03

       But they're, but they're often, they're often feeding in suboptimal areas. So this is the place with all the best food. The adults will kick you off, so now you have to feed somewhere else. Maybe the food isn't as good, in which case you need to eat more of it, so it takes longer. Or maybe it's the one next to the edge of the forest where the T-rexes hide. But either way, you're stuck there. And then you don't really know what you're looking for and you haven't got the armor. So guess who's getting eaten? Like, this is... Again, there's lots of exceptions. You can't have nature without things like that. But this is the absolute rule of thumb for how foraging and growth and predation operate across everything from fish to starf- fish as predators, starfish, praying mantis, all the way up to things like big cats via stuff like crocodiles. It, it's how it works. So it'd be very weird if it didn't also operate for dinosaurs. And then, as I say, we've actually got the direct evidence for this from bite marks and stomach contents. They're taking small stuff.

   16. LFLex Fridman29:59

       Bite marks give a lot of information.

   17. DHDave Hone30:01

       Yeah.

   18. LFLex Fridman30:02

       That's a powerful signal in paleontology.

   19. DHDave Hone30:04

       Yeah, absolutely. I've done really quite a lot of work on it, and they can tell you an awful lot if you've got the right understanding of the burial conditions, because you... Weird thing that I think a lot of people don't appreciate is you basically can't take fossils at face value, particularly when you're trying to get into stuff like behavior and ecology because...So between the animal dying and the paleontologist digging it up, potentially quite a lot has happened, and that's where it's really easy to start misinterpreting things because if you just go... I- I had one like this not too long ago where I was an editor on a paper, and the- the authors had done a pretty good job, to be fair, but it was this discussion of whether or not several animals were together at the time of their death.

   20. LFLex Fridman30:50

       Mm-hmm.

   21. DHDave Hone30:51

       So multiple, um, theropods together in this quarry, and it's like, right, but there was loads of debris and you had loads of things like fish scales and other small bones, and it's like, okay, but this looks like these animals di- potentially died somewhere else, and then a flood or a river washed them into this bay or a channel or it then... The water level dropped and they ended up together, but that doesn't necessarily mean they were together when they died. And so just 'cause you've got three animals together, what is potentially the story of how they got there?

   22. LFLex Fridman31:27

       So you have to consider multiple explanations and then try to figure out what is the most likely.

   23. DHDave Hone31:31

       Yeah.

   24. LFLex Fridman31:31

       Okay.

   25. DHDave Hone31:31

       Or what can you test with various bits of evidence? So there was some, uh, tyrannosaur-inflicted bite marks on a duck bill from Mongolia that I worked on years ago. The specimen was from Mongolia but it was held in Japan in a Japanese museum. I was working with the Japanese on it. And I'm- I'm not a taphonomist or the study of, like, decay and the history of specimens, and I am in no way, shape, or form a geologist. I did zoology for my degree. (laughs) Um, but the guys I was working with, like, they were really hot on erosion and damage, and they were looking at some of the way the bones had been damaged, and they're like, "Okay, we're pretty confident that the bite marks are sitting on top of erosion."

   26. LFLex Fridman32:14

       What does that mean?

   27. DHDave Hone32:15

       So it means that the animal had died, uh, and it was found in a- it was found in sand covered but in what would have been a river channel.

   28. LFLex Fridman32:23

       Mm-hmm.

   29. DHDave Hone32:23

       So this animal has died, washed downstream, ended up on a sandbank. The sand is whipping past 'cause I've been in a sandstorm (laughs) in-

   30. LFLex Fridman32:31

       Mm-hmm.
5. 38:45 – 59:17

   History of dinosaurs on Earth

   1. DHDave Hone38:45

      far.

   2. LFLex Fridman38:45

      How far were they spread? Where did they l- where did they live?

   3. DHDave Hone38:49

      So the ones we've found, you've got them from Alberta down to probably New Mexico. There's some, I want to say there's some tyrannosaurine, so very close to T-rex, teeth that may or may not be T-rex in New Mexico. There's similar teeth in Mexico proper, down in Coahuila, um, so about halfway down Mexico.

   4. LFLex Fridman39:12

      Mongolia also, or no?

   5. DHDave Hone39:13

      So Mongolia you have a thing called Tarbosaurus, which is a very, very close relative of T-rex. It's the nearest species, or nearest genus, that we have. Um, but T-rex is probably occupying almost all of western North America.

   6. LFLex Fridman39:28

      Okay.

   7. DHDave Hone39:28

      So at times the east was kind of split off and, and separate.

   8. LFLex Fridman39:31

      But the entire surface of Earth had dinosaurs on it.

   9. DHDave Hone39:34

      Oh, yeah.

   10. LFLex Fridman39:35

       Well, most of it.

   11. DHDave Hone39:35

       Yeah. We- we've got them in Antarctica. We've got them in Antarctica even close to the mass extinction event.

   12. LFLex Fridman39:41

       Just an insane number of dinosaur species all over the Earth, just the same kind of variety we have in the animal kingdom today, you just have in the dinosaur.

   13. DHDave Hone39:50

       I mean, this is, this is, like how many dinosaur species were there? I don't know. I basically wrote an entire book chapter about this because there's so many, "But this would make the number high," "But this would make the number lower," "But this would make the number high," "But this would make the number lower," counter versus counterarguments, that you can guesstimate almost any number and probably be very accurate or very far out.

   14. LFLex Fridman40:15

       Yeah, but we should say that a large number of dinosaur species are constantly being discovered.

   15. DHDave Hone40:19

       Yeah. So we've named, give or take, in the realm of 1,500, 1,600 valid species. Though that is, not everyone agrees on every species, but most people would be satisfied with that number. But we also name in the realm of 40 to 50 a year, and we've been doing that for at least the last 10, 12 years. That number is rocketing up. Shows no signs of slowing down. There's loads of ar- like, we still never really explored India very much. We're starting to find entirely new beds in places like Ecuador. Um, Argentina we know has a ton of stuff but we've never excavated there very much. Australia we know there's a ton of stuff and we haven't excavated there very much. Um, so there's lots of places, even now, to still go through.

   16. LFLex Fridman41:05

       This is a good moment to take a brief tangent and look at paleontology. So h- how do we, how do we find these fossils? What's the, uh, what's the magic? What's the science? The art?

   17. DHDave Hone41:14

       The same way, more or less, that people did in the 1750s, or whenever you first start getting them. Th- there's... For dinosaurs in particular, but this is true of the vast majority of stuff, there's essentially two ways of doing it. The simple one is where you have quarries of particularly things like lithographic limestone, so the printing limestones, or stuff that's very similar to that, uh, sometimes it's often volcanic, um, you get these super, super, super fine layers of sedimentation. And that's where you get these places with exceptional preservation. Whenever you see like the feathers, or almost always, whenever you see feathered dinosaurs where it's like, "Oh, we got the skin, we got the claws," and like the whole skeleton's laid out. So Archaeopteryx being like the, the first bird and it's an absolute classic example, it's from these beds. And there you find them by basically splitting limestone. We don't usually dig for them. It's because there are quarry workers and people who are already doing this because the stone is useful, because there might be one decent fossil for every, you know, few hundred tons of rock you shift. In which case, you could get every paleontologist in the world there for a couple of years and you wouldn't find very much. You rely on the fact that there's hundreds of guys doing this constantly. And then sooner or later they'll find something and then you've got it.... that's the super easy way. The only slightly more (laughs) complicated way is you go to somewhere where geologically we know it's the right age and it's the right kind of rock, and ideally, fossils have been reported from there before. And again, you know, geologists map all the world's geology years ago in quite a lot of detail. There's, there's gaps, there's places where we don't have the details, but in general we know. And then you go there, and then you walk around, and you look, and that's basically it.

   18. LFLex Fridman43:05

       And you're looking for something that's sticking out of the rock.

   19. DHDave Hone43:07

       Yeah. So you always get the ... So there's this constant, and I think, you know, borderline myth of the idea that dinosaurs and mammoths and lots of other fossil things, like, entered lots of indigenous cultures because it's impossible that the guys were wandering around, say Dakota, and the Native Americans didn't come across some dinosaur fossils. That I'd agree with. It's pretty much impossible they didn't come across some dinosaur fossils. Did they come across a whole skeleton laid out on the ground? No, because those don't usually exist, because even if they're tougher or ... It doesn't matter if they're tougher or weaker than the surrounding rock. Dinosaur bones are, you know, in some way, shape, or form, they're lithified. They, they turn to rock, and they will absorb some of the minerals from whatever they've been buried in. And so even in places like Mongolia and Northern China where I've been to, where actually the, the fossil bone is quite a lot tougher than the sandstone that it's embedded in, like, you can find a bit of bone and pull it out, like, almost like rub it with your hands and the, the sand comes off, and there's your bone. They will decay pretty quickly. You know, sandstorms, you know, sand just etches stuff. Um, the tiniest bit of moisture, particularly in winter, gets into the cracks. Bones are incredibly porous. That freezes, that expands, that cracks. Bones just shatter. And yeah, you find shattered bone on the surface everywhere. What you rarely find is a decent bone on the surface, let alone a skeleton.

   20. LFLex Fridman44:43

       So there has to be something that's sticking out just a tiny bit-

   21. DHDave Hone44:46

       So that you can see it, but it's still buried. Right. And it, and it happens. The, the, the greatest one that I saw, or that I, that I didn't see, it happened by ... with a friend of mine when we were in, um, Northern China, and he went, "Yeah, I can see a bit of a claw sticking out of a hill." And it was. It was like the, this, this much. You could see-

   22. LFLex Fridman45:05

       Yeah.

   23. DHDave Hone45:06

       ... you know, less than a centimeter coming out of a hillside. And it's like, so, you know-

   24. LFLex Fridman45:11

       That's the dream, right?

   25. DHDave Hone45:12

       ... dig, dig a little bit, and there's a little bit more. Dig a little bit, and there's a little bit more. Dig a little bit, there's a little bit more. Okay, and then the system we were running there is some guys were searchers and some guys were diggers. So he and I were searchers. We're told, "Okay, you guys have ... You guys." He found it. "You found something. Go and look for something else. We'll dig it out." And so we come back a couple of days later and check in on the digging team. "So what is it then?" "Oh, it's a complete skeleton." And it was. It was a thing, very, very close relative of, um, velociraptor, ended up naming it linheraptor, so the raptor from Linher, which was the nearest town. And it was ... Yeah, the legs were a little messed up because water had got to them, and the end of the tail was missing, and that was about it. So, like, 90-plus percent complete skeleton, and it had been found with, you know, five mil, a couple of sixteenths of an inch of bone sticking out of a hill. And that's what you want, because every so often behind that is a whole skeleton. If you're looking for skeletons on the surface, they're gonna be gone before you get to them.

   26. LFLex Fridman46:11

       And when it's a near complete skeleton ... You, you did a show of, uh, terrible lizards on, uh, Stan.

   27. DHDave Hone46:18

       Oh, yeah.

   28. LFLex Fridman46:18

       The T-rex fossil that sold for $31.8 million.

   29. DHDave Hone46:22

       Signs of- (laughs)

   30. LFLex Fridman46:23

       So that, that's a nice sort of, uh, big adult T-rex. So looking at a fossil like this-
6. 59:17 – 1:12:22

   $31.8 million T-Rex fossil

   1. DHDave Hone59:17

   2. LFLex Fridman59:17

      So okay, let's complete the journey of Stan to the museum to, like, you get- you get to the process of cleaning everything, stitching it all together.

   3. DHDave Hone59:25

      Yeah. Like Mark and like that's suggested, you know, th- this can be even on an animal that size. Borealopelta is, you know, four or five meters long. We've only gone and got the front two thirds of it. Yeah, thi- this can be, like, needle level stuff.

   4. LFLex Fridman59:37

      That's how you get to the 30,000 hours.

   5. DHDave Hone59:39

      Yeah, exactly that, if it's that quality and you want to get everything open. And then something like Stan, actually really complicated skull. The skull is full of lots of little bones. The bones are really fragile, so that just adds to the time. I mean, at least the ankylosaurids are ... (laughs) the skull is just this giant solid block of bone, which makes life a little bit easier. So yeah, they're gonna put those hours in, and that's really gonna help them sell the animal, which is ultimately what happened. I mean, Stan sat in the Black Hills Institute for decades. I mean, '87 and they sold it in like 2020, so they had it for 30 years, uh, sitting in their kind of little museum. And then my understanding was basically the brothers broke the company up and that's why they sold it.

   6. LFLex Fridman1:00:23

      Yeah, but it was still incredibly surprising that it was sold for 31 million.

   7. DHDave Hone1:00:26

      Yeah. I mean, far more than I think anyone thought it was going to. I mean, I- I liken ... Well, you know, if you're not buying, like, teeth or an ammonite in some small fossil shop, you know, when you're buying, talking about things like whole dinosaurs and whole tyrannosaurs, I think it's a bit like the art market in- it's worth what people will pay for it.

   8. LFLex Fridman1:00:45

      Yeah.

   9. DHDave Hone1:00:46

      And so, you know-

   10. LFLex Fridman1:00:47

       Yeah.

   11. DHDave Hone1:00:47

       ... plenty of T-rexes had sold for a few million dollars and therefore everyone thought it would- might be five, you know. M- ten would be an absurd sum of money, and then (laughs) yeah, it- it went for 30 and it's like, okay, well-... two- I was gonna say, someone wanted it that bad, but clearly not two people wanted it that bad 'cause if only one guy is prepared to bid 30, then it goes for, you know, a million more than the next highest bidder. But presumably, two people, if not three, bid it to get that high.

   12. LFLex Fridman1:01:19

       Yeah, it was, uh, anonymous at the time, but now, it's, uh, Abu Dhabi's Department of-

   13. DHDave Hone1:01:22

       Yeah.

   14. LFLex Fridman1:01:22

       ... Culture and Tourism came out that they were the ones.

   15. DHDave Hone1:01:24

       I know they've got it.

   16. LFLex Fridman1:01:25

       And, uh, and then it, that record has been since beaten apparently by, uh-

   17. DHDave Hone1:01:29

       By Apex, the stegosaurus, which I still haven't seen, though a friend of mine has sent me some photos of this thing.

   18. LFLex Fridman1:01:36

       Is it impressive to you, this thing?

   19. DHDave Hone1:01:37

       No, not especially. That's why I can't imagine that it sold for that much. It's a really nice stegosaurus. It's pretty big stegosaurus.

   20. LFLex Fridman1:01:47

       Well preserved.

   21. DHDave Hone1:01:47

       I've seen other very good stegosaurus, and I don't understand why that's worth that much more than something like Stan. But it, it shows you the market. So, so we're here in London. There's a stegosaurus called Sophie in the Natural History Museum in London. Sophie is a young animal, so she's not very big. I mean, it's a sizable specimen. I'd say five-ish, six meters off the top of my head, total length. But Sophie's, like, truly exceptional. Like, there's a couple of plates missing, a handful of ribs, a couple of bones in the tail. I think a couple of toe bones. Like, this is by far the most complete stegosaurus out there.

   22. LFLex Fridman1:02:25

       Wow.

   23. DHDave Hone1:02:25

       That sold for, I think, 250,000 pounds, so maybe $400,000 about a decade ago. So this has now gone up, like, 100-fold for an animal which is quite a bit bigger but is way less complete. So, uh, for me, those two things kind of balance out because size is always impressive and that's what the public likes, but also a complete one is better than a half a one or two-thirds a one. So yeah. So how has the price gone up 100 to, or from, yeah, 400,000 to 40,000,000 in 10 years for roughly the same thing?

   24. LFLex Fridman1:03:03

       A T-rex is a little bit more epic than a stegosaurus.

   25. DHDave Hone1:03:06

       Well, that's the thing. T-rex has a massive premium on it-

   26. LFLex Fridman1:03:08

       Yeah.

   27. DHDave Hone1:03:08

       ... because it's, yeah, stegosaurus is one of those top-tier, you know, it's, you can virtually do the list, you know. T-rex, triceratops, diplodocus, brontosaurus, stegosaurus. It's in that first six or seven... Okay, these days, velociraptor next to Jurassic Park.

   28. LFLex Fridman1:03:27

       (laughs)

   29. DHDave Hone1:03:27

       But it's, like, it, like, but, you know, there's, that's the list of like seven or eight things that any random human who doesn't care about dinosaurs and doesn't know anything about dinosaurs, but they've probably heard of them. You know, stegosaurus is in that list and would have an idea of what it looked like. Oh, yeah, it's got like the big stuff stuck along the back. You know, you, you'd get that answer from almost any, you know, 99% of people on the street. But yeah, it's (laughs) not a T-rex. So how it's worth, yeah, 50% more and it's not even a particularly complete skeleton, Apex, to my understanding, like I, I don't, I don't get it. (laughs)

   30. LFLex Fridman1:04:05

       Actually, uh, since we're on the topic of money, if I gave you, let's say, $10 billion, how would you spend it? You are forced, I will, I force you to spend it on dinosaur-related things. How would you spend it?
7. 1:12:22 – 1:31:12

   T-Rex's skull and bone-crushing bite force

   1. LFLex Fridman1:12:22

      We've taken a few tangents, but let's, uh, continue on the thread of T-Rex.

   2. DHDave Hone1:12:27

      Yeah.

   3. LFLex Fridman1:12:27

      Go, go to the skull.

   4. DHDave Hone1:12:29

      Yeah.

   5. LFLex Fridman1:12:29

      So, uh, the skull of T-Rex is iconic. So you describe it as being incredibly robust and overbuilt.

   6. DHDave Hone1:12:36

      Yeah. There's a lot of bone on there. Uh, I said we mentioned a couple of other things like Giganotosaurus or this, you know, giant carnivore. Uh, if you put Giganotosaurus T-Rex in, that's the one. So that's, yeah, (laughs) that's on my old blog. It's not my image. Um-

   7. LFLex Fridman1:12:49

      What are we looking at on the left and the right?

   8. DHDave Hone1:12:50

      So you've got T-Rex on the left in orange and Giganotosaurus on the right in red. As I said, they're pretty similarly sized, but just look at the robusticity. Like, the front of the snout of T-Rex is all bone, and yet the major openings, this is a thing called the antorbital fenestra, the opening in front of the orbit, it's absolutely massive in Giganotosaurus. It's like half the skull.... the opening at the back of the skull is much bigger. The opening in the lower jaw is much bigger, and actually the jaw, what you can't see, side to side, is much thinner. So their heads are the same size, and as animals, they are about the same linear dimensions. But you can just see, there's just way more bone (laughs) in the T-Rex.

   9. LFLex Fridman1:13:30

      Yeah, it's incredible.

   10. DHDave Hone1:13:31

       So it, this is, like it's not overbuilt, it's obviously, it's evolved that this is the right amount of bone for the stresses and strains, for what it's doing and how it's acting. But you compare it to anything that's not a very large tyrannosaur, and suddenly you see just how much bone has gone into it. It is a very large... It's an absolutely large head, but it's a very heavy head with a lot of bone. And a lot of that bone is there to resist all the forces of all the muscles because it has this giant, super powerful bite, which again, you can see in the teeth.

   11. LFLex Fridman1:14:00

       So the bone and the muscles kind of evolve together to get bigger-

   12. DHDave Hone1:14:02

       Yeah, yeah, yeah.

   13. LFLex Fridman1:14:02

       ... and bigger and bigger and bigger. So you need this kind of structure for the power that, uh-

   14. DHDave Hone1:14:07

       Yeah.

   15. LFLex Fridman1:14:07

       ... the crush has.

   16. DHDave Hone1:14:07

       So one of the big things, uh, tyrannosaurs have, uh, and this goes all the way down to the, the, the earliest tyrannosaurs were like our size. (laughs) Like little diddy things, like two, three meters long, be a meter and a half tall. Um, but they have fused nasals, so the pair of bones that, i- in us there's not a lot there, but obviously in something like a dog or something like a baboon with a long nose, it's like the whole top of the snout. And there's two, one each side. In tyrannosaurs, they fuse together, so it forms a solid bit of bone. So the whole top of the nose is solid, and then that makes the skull just fundamentally more rigid and able to take more power through it. The very early ones weren't super biters, I suspect, but they do also, but they do have the little flattened teeth at the front. So I strongly suspect the fused nasals, at least originally, is for resisting that. 'Cause again, if you've got a long nose and you're pulling with quite a lot of force at the very tip, that's gonna bend your snout.

   17. LFLex Fridman1:15:01

       Mm-hmm.

   18. DHDave Hone1:15:01

       So strengthen that.

   19. LFLex Fridman1:15:03

       Can you speak to the evolution from the smaller to the bigger of the T-Rex? What, what were some of the evolutionary pressures? What, like what, w- what's the story of the evolution?

   20. DHDave Hone1:15:11

       So tyrannosaurs go back to the Middle Jurassic. So tyrannosaurs were around for 100 million years. So from about 160-ish, 165-ish million years till the extinction, 66.5 I think is the current dating on that. So yeah, you've got 100 million years of them, and the Middle Jurassic annoyingly is probably the bit of the Mesozoic, so the whole dinosaur period, that we know the least of. Just by chance, we just don't have many rocks exposed of the right age that are fossil-bearing. Um, but we've got two or three tyrannosaurs from that time. And yeah, they're, they're really quite diddy. Yeah, they'd be chest high to us, two or three meters long including the tail. Probably more like three, a lot of them. Um, little heads, long arms. They, they look like every other carnivore going. There's, there's not a lot special to them, um, at this point. They've only just separated from their nearest groups, which is actually something like the ancestors of Giganotosaurus, actually. Um, they do have the fused nasals early on. They do have these special little teeth at the front of the jaw very early on. They're feathered early on. Definitively, we have skeletons with feathers on them that are early tyrannosaurs, uh, at least until the early Cretaceous. Um, but yeah, they're knocking around as relatively small animals in Europe and Asia. We have a couple from the UK. Uh, we have a whole bunch from China. There's stuff from like Kyrgyzstan and places like this. I think there's one, a relatively early one from Russia. Um, and then when they get into the early Cretaceous, they start getting quite a bit bigger. Uh, so someone like Yutyrannus if you wanna... There you go. So Yutyrannus is fuzzy. Um, we have three specimens definitively feathered. Um-

   21. LFLex Fridman1:16:56

       (laughs)

   22. DHDave Hone1:16:56

       ... it gets to six, seven meters long.

   23. LFLex Fridman1:16:59

       There's something funny-looking about the sexy, smaller, earlier version of the T-Rex.

   24. DHDave Hone1:17:04

       But, but again, this is seven, eight meters, maybe weighs half a ton or a ton. Like we, we are very much on the menu for an animal that size, and it's-

   25. LFLex Fridman1:17:11

       Yeah.

   26. DHDave Hone1:17:12

       ... massive and dangerous. Quite what triggered them, there's general patterns in evolution of size change and one, a famous one called Cate's rule I've worked on a fair bit, which is the idea that over time, things tend to get bigger. And they do for various different reasons, one of which is just pure almost like diffusion. If you start small and you evolve, well you can't get much smaller, but you can always get bigger. So you, you'll naturally kind of diffuse away. Whereas if you're a blue whale, you probably can't get much bigger and its descendants will probably end up being smaller. But there are reasons that bigger things do better. You can hunt more stuff. You are more energy efficient. You can move more efficiently. Um, you're dominant in contests, particularly with conspecifics. If you're trying to win a territory or win mating rights, bigger things usually beat up smaller things. So there's gonna be selection favoring them. Um, but then big things don't usually do well in extinction events, so that tends to reset the clock by killing off the big stuff and then smaller stuff does better again.

Episode duration: 3:36:25