WEBVTT 00:00:00.000 --> 00:00:02.980 Imagine, if you will, a creature that acts as 00:00:02.980 --> 00:00:06.599 a mirror. Not a physical mirror, but a mirror 00:00:06.599 --> 00:00:09.359 for our own intelligence, our own assumptions, 00:00:09.679 --> 00:00:13.259 and really our understanding of the history of 00:00:13.259 --> 00:00:15.240 life on Earth. That's a great way to put it. 00:00:15.300 --> 00:00:17.280 And I'm not talking about some mythical shapeshifter. 00:00:17.629 --> 00:00:20.370 I'm talking about a pile of old bones. It really 00:00:20.370 --> 00:00:22.710 is the ultimate shapeshifter of the fossil record, 00:00:22.829 --> 00:00:24.850 though. I mean, if you took a snapshot of how 00:00:24.850 --> 00:00:28.789 scientists visualized this animal in, say, 1830. 00:00:28.989 --> 00:00:31.690 Okay. Then you took another in 1850, then another 00:00:31.690 --> 00:00:34.329 around 1900, and then you look at it today. You'd 00:00:34.329 --> 00:00:35.789 think they were completely different animals. 00:00:35.810 --> 00:00:38.350 You would swear you were looking at four, maybe 00:00:38.350 --> 00:00:41.670 five completely different species. It's an incredible 00:00:41.670 --> 00:00:44.429 transformation. We've had the giant sluggish 00:00:44.429 --> 00:00:48.039 lizard model. We've had the horned. rhinoceros 00:00:48.039 --> 00:00:50.439 -like elephant. The Crystal Palace version. Then 00:00:50.439 --> 00:00:52.979 the Godzilla -style kangaroo tripod dragging 00:00:52.979 --> 00:00:56.340 its tail. And now we have the modern version, 00:00:56.520 --> 00:00:58.359 the all -terrain vehicle of the Cretaceous. The 00:00:58.359 --> 00:01:01.100 ultimate herbivore. We are talking, of course, 00:01:01.119 --> 00:01:04.359 about the Iguanodon. The one and only. And it's 00:01:04.359 --> 00:01:07.439 so fascinating because Iguanodon isn't just another 00:01:07.439 --> 00:01:11.099 dinosaur it is in many ways the dinosaur it's 00:01:11.099 --> 00:01:14.780 the barometer for the entire field of paleontology 00:01:14.780 --> 00:01:17.060 right because if you want to know what humans 00:01:17.060 --> 00:01:19.640 thought about dinosaurs at any specific point 00:01:19.640 --> 00:01:22.239 in the last 200 years you just have to look at 00:01:22.239 --> 00:01:25.159 how they were drawing iguanodon exactly it tracks 00:01:25.159 --> 00:01:27.900 the evolution of our science perfectly from the 00:01:27.900 --> 00:01:31.170 early days of you know giant lizards. Which was 00:01:31.170 --> 00:01:33.849 a total guess. A complete shot in the dark, really. 00:01:34.329 --> 00:01:37.609 Then it moved to the slow, cold -blooded reptiles 00:01:37.609 --> 00:01:40.709 of the mid -20th century. And finally, to the 00:01:40.709 --> 00:01:43.930 active, dynamic, successful animals we know they 00:01:43.930 --> 00:01:46.310 were today. And it's historically heavy, too. 00:01:46.489 --> 00:01:49.230 I mean, this is foundational stuff. Along with 00:01:49.230 --> 00:01:51.530 megalosaurus and hylasaurus, this was one of 00:01:51.530 --> 00:01:53.609 the original three genera used to define the 00:01:53.609 --> 00:01:57.200 very word dinosauria. That's right. Before Iguanodon 00:01:57.200 --> 00:01:59.219 and the others, the word dinosaur literally didn't 00:01:59.219 --> 00:02:01.579 exist. It is the foundation upon which the entire 00:02:01.579 --> 00:02:04.000 house was built. So our mission for this deep 00:02:04.000 --> 00:02:06.480 dive is pretty clear. We're going to unpack the 00:02:06.480 --> 00:02:08.680 200 -year -old cold case of this animal. We're 00:02:08.680 --> 00:02:10.479 going to look at the myths. Oh, there are so 00:02:10.479 --> 00:02:13.000 many myths. Like that famous horn on the nose 00:02:13.000 --> 00:02:16.009 that wasn't a horn at all. We're going to descend 00:02:16.009 --> 00:02:18.909 into a Belgian coal mine to visit a dinosaur 00:02:18.909 --> 00:02:21.310 graveyard. And we're going to figure out how 00:02:21.310 --> 00:02:24.409 this so -called cow of the Cretaceous actually 00:02:24.409 --> 00:02:26.750 lived. And I'll tell you, calling it a cow is 00:02:26.750 --> 00:02:28.949 really selling it short. This thing was an evolutionary 00:02:28.949 --> 00:02:31.469 masterpiece. So let's start at the beginning. 00:02:31.610 --> 00:02:33.909 And in paleontology, the beginning is usually 00:02:33.909 --> 00:02:37.189 just a scrap, a fragment. It almost always is. 00:02:37.270 --> 00:02:39.830 In this case, it's a tooth. Take us back. We're 00:02:39.830 --> 00:02:43.210 in Sussex, England, the 1820s. What does the 00:02:43.210 --> 00:02:46.479 world look like scientifically? The 1820s. This 00:02:46.479 --> 00:02:49.400 is a time when the concept of deep time is just 00:02:49.400 --> 00:02:52.360 barely starting to form. People are finding fossils, 00:02:52.599 --> 00:02:56.430 sure. They find big bones in quarries. But the 00:02:56.430 --> 00:02:58.289 framework isn't there yet. So they don't know 00:02:58.289 --> 00:03:00.550 what they're looking at. Not really. If you found 00:03:00.550 --> 00:03:02.550 a massive thigh bone, you'd probably say it was 00:03:02.550 --> 00:03:04.770 an elephant brought by the Romans or maybe. A 00:03:04.770 --> 00:03:07.969 giant human. A giant human from the Bible, Goliath's 00:03:07.969 --> 00:03:10.849 cousin or something. That was a very common explanation. 00:03:11.069 --> 00:03:14.129 The idea of extinct worlds of giant reptiles 00:03:14.129 --> 00:03:16.569 just wasn't in the public consciousness. And 00:03:16.569 --> 00:03:19.210 into this world steps Gideon Mantell. Gideon 00:03:19.210 --> 00:03:21.849 Mantell. He's a fascinating character. He's a 00:03:21.849 --> 00:03:24.770 country doctor, a general practitioner in Lewis 00:03:24.770 --> 00:03:28.620 Sussex. Not a formal academic. So his day job 00:03:28.620 --> 00:03:30.780 is riding around on horseback visiting patients. 00:03:31.020 --> 00:03:34.060 Exactly. Delivering babies, setting bones. But 00:03:34.060 --> 00:03:36.340 his real passion, the thing that keeps him up 00:03:36.340 --> 00:03:39.789 at night, is geology. He is obsessed with the 00:03:39.789 --> 00:03:42.189 rocks of the Weald. He collects everything. And 00:03:42.189 --> 00:03:44.229 there's a famous story about the discovery of 00:03:44.229 --> 00:03:46.770 Iguanodon. I feel like I read this in every dinosaur 00:03:46.770 --> 00:03:49.870 book I had as a kid. The legend of Marianne Mantel. 00:03:49.990 --> 00:03:53.330 Ah, yes. The legend. It's a beautiful vignette, 00:03:53.389 --> 00:03:55.629 isn't it? It's perfect. The story goes that in 00:03:55.629 --> 00:03:59.110 the summer of 1822, Gideon is visiting a patient. 00:03:59.189 --> 00:04:02.650 His wife, Marianne, accompanies him. While he 00:04:02.650 --> 00:04:05.050 is inside the house tending to the sick, she's 00:04:05.050 --> 00:04:07.449 wandering down the lane, kicking at a pile of 00:04:07.449 --> 00:04:10.009 road metal. Just stones used to patch the road. 00:04:10.189 --> 00:04:12.430 Right. And she spots something shiny, something 00:04:12.430 --> 00:04:15.210 different. She sees a strange shape in the sandstone. 00:04:15.310 --> 00:04:17.490 She picks it up, shows it to Gideon when he comes 00:04:17.490 --> 00:04:19.490 out, and he realizes it's a fossil tooth unlike 00:04:19.490 --> 00:04:22.089 anything he's ever seen. It's the perfect behind 00:04:22.089 --> 00:04:25.170 -every -great -man story. It gives her the credit 00:04:25.170 --> 00:04:29.870 for this world -changing discovery. But we have 00:04:29.870 --> 00:04:33.009 to be the buzzkills today. Is it true? It's... 00:04:33.470 --> 00:04:36.009 It's complicated. It's likely a myth or at least 00:04:36.009 --> 00:04:38.750 a highly romanticized version of events. So he 00:04:38.750 --> 00:04:41.430 made it up. Well, Mantel himself was very inconsistent 00:04:41.430 --> 00:04:44.949 about it. In his early writings, say around 1827 00:04:44.949 --> 00:04:48.069 and 1833, he stated that Marianne found them. 00:04:48.149 --> 00:04:50.470 He gives her the credit. OK. But much later, 00:04:50.550 --> 00:04:54.029 in 1851, shortly before he died, he explicitly 00:04:54.029 --> 00:04:56.810 wrote in a book that he found them himself. The 00:04:56.810 --> 00:04:59.290 classic retraction. Actually, it was me all along. 00:04:59.430 --> 00:05:01.610 Right. And, you know, historians who have looked 00:05:01.610 --> 00:05:03.490 into his medical practice know. that doctors 00:05:03.490 --> 00:05:05.709 in the 1820s almost never took their wives on 00:05:05.709 --> 00:05:07.769 patient calls. It just wasn't done. It would 00:05:07.769 --> 00:05:09.829 have been unprofessional. Highly. So the whole 00:05:09.829 --> 00:05:11.829 premise of the story is a bit shaky. So where 00:05:11.829 --> 00:05:13.850 did the teeth actually come from? What's the 00:05:13.850 --> 00:05:16.639 more likely scenario? It's quite possible Gideon 00:05:16.639 --> 00:05:19.620 found them himself on one of his rides. Or, and 00:05:19.620 --> 00:05:21.740 this is very common, he bought them from the 00:05:21.740 --> 00:05:24.439 quarry men. The local workers knew the doctor 00:05:24.439 --> 00:05:26.920 paid for curiosities, so they had saved the weird 00:05:26.920 --> 00:05:29.379 rocks for him. That makes a lot of sense. But 00:05:29.379 --> 00:05:31.579 regardless of who physically picked it up, whether 00:05:31.579 --> 00:05:34.420 it was Marianne or Gideon, the teeth were the 00:05:34.420 --> 00:05:36.620 spark. And what was so confusing about them? 00:05:36.959 --> 00:05:40.019 He'd seen other fossils before. He had. He'd 00:05:40.019 --> 00:05:42.040 even found large bones that he thought belonged 00:05:42.040 --> 00:05:46.120 to a giant crocodile. But crocodiles are carnivores. 00:05:46.199 --> 00:05:49.079 Their teeth are simple conical spikes for gripping 00:05:49.079 --> 00:05:51.660 and tearing. But these were different. Completely 00:05:51.660 --> 00:05:54.139 different. They were leaf -shaped. They had serrated 00:05:54.139 --> 00:05:56.540 edges, like a steak knife. And most importantly, 00:05:56.740 --> 00:05:58.860 they were worn flat on the top. Like a horse's 00:05:58.860 --> 00:06:02.430 tooth. Or a cow's. Exactly. Or a cow's. They 00:06:02.430 --> 00:06:05.170 were grinding teeth. And in 1822, that was a 00:06:05.170 --> 00:06:08.629 paradox. Why? Because everyone knew that modern 00:06:08.629 --> 00:06:12.009 reptiles, lizards, iguanas, crocodiles were meat 00:06:12.009 --> 00:06:14.550 eaters or bug eaters. The idea of a reptile that 00:06:14.550 --> 00:06:16.610 was an herbivore that didn't fit the accepted 00:06:16.610 --> 00:06:19.509 model and the idea of a giant reptile that ate 00:06:19.509 --> 00:06:21.629 plants, that was just impossible to them. So 00:06:21.629 --> 00:06:23.949 he knows he has something revolutionary. He takes 00:06:23.949 --> 00:06:27.069 these teeth to the experts. The Royal Society 00:06:27.069 --> 00:06:30.040 in London. He does. He presents them in 1822. 00:06:30.279 --> 00:06:33.279 And he gets absolutely stonewalled, just shut 00:06:33.279 --> 00:06:35.560 down. Who were the gatekeepers at the time? Who 00:06:35.560 --> 00:06:38.139 was he up against? The biggest names in the business. 00:06:38.699 --> 00:06:42.800 First, William Buckland. He's an eccentric genius 00:06:42.800 --> 00:06:45.500 at Oxford, a giant in the field. He looks at 00:06:45.500 --> 00:06:47.500 the teeth and dismisses them. What does he say 00:06:47.500 --> 00:06:50.899 they are? He says they are fish teeth. Fish teeth? 00:06:51.160 --> 00:06:54.079 Really? To be fair, some fish do have grinding 00:06:54.079 --> 00:06:57.199 teeth for crushing coral or shells, but it was 00:06:57.199 --> 00:06:59.740 a very dismissive categorization. It was basically 00:06:59.740 --> 00:07:02.560 saying, this isn't interesting. And then it gets 00:07:02.560 --> 00:07:05.319 worse. It gets much worse. Charles Lyell, who 00:07:05.319 --> 00:07:07.160 would go on to be the father of modern geology, 00:07:07.519 --> 00:07:10.379 takes the teeth to Paris to show them to Georges 00:07:10.379 --> 00:07:12.100 Cuvier. And for those who don't know, Cuvier 00:07:12.100 --> 00:07:14.300 is basically the god of anatomy at this point. 00:07:14.399 --> 00:07:17.790 He is the Napoleon of science. The man is a legend. 00:07:17.889 --> 00:07:21.029 He can supposedly look at a single bone and reconstruct 00:07:21.029 --> 00:07:24.310 an entire animal. He's never wrong. So what does 00:07:24.310 --> 00:07:26.870 the great Cuvier say? Cuvier looks at these teeth 00:07:26.870 --> 00:07:30.250 and says, these are the upper incisors of a rhinoceros. 00:07:30.389 --> 00:07:32.829 A rhino. So he thinks Mantell has found a mammal. 00:07:33.149 --> 00:07:35.290 A tertiary mammal, to be specific, something 00:07:35.290 --> 00:07:38.470 relatively recent in geological terms. He assumes 00:07:38.470 --> 00:07:40.350 the teeth must have been from a younger rock 00:07:40.350 --> 00:07:43.350 layer and just got mixed into the older Cretaceous 00:07:43.350 --> 00:07:45.610 stuff by accident. That must have been devastating 00:07:45.610 --> 00:07:48.600 for Mantell. He's just a country doctor. And 00:07:48.600 --> 00:07:50.319 the world's leading scientist is telling him, 00:07:50.339 --> 00:07:53.240 stick to medicine, kid. You found a rhino tooth. 00:07:53.459 --> 00:07:55.980 It was crushing. I mean, can you imagine? But 00:07:55.980 --> 00:07:59.180 this is where Mantell's stubbornness or his genius 00:07:59.180 --> 00:08:02.560 saves the day. He knew the geology. He knew those 00:08:02.560 --> 00:08:05.100 teeth came from the Tillgate Forest sandstone. 00:08:05.759 --> 00:08:08.100 which is ancient. It's from the age of reptiles. 00:08:08.180 --> 00:08:10.639 No rhinos back then. Absolutely no mammals back 00:08:10.639 --> 00:08:13.000 then, certainly not rhinos. So he refused to 00:08:13.000 --> 00:08:15.680 accept Cuvier's verdict. He kept digging. And 00:08:15.680 --> 00:08:18.199 eventually Cuvier comes around. He does. And 00:08:18.199 --> 00:08:20.699 this is a mark of a true scientist. In 1824, 00:08:20.920 --> 00:08:24.100 Mantel sends more specimens, better ones. Cuvier 00:08:24.100 --> 00:08:26.199 takes a second look, sees the wear patterns, 00:08:26.379 --> 00:08:29.000 realizes his mistake, and he writes a letter 00:08:29.000 --> 00:08:31.339 to Mantel. What does it say? It says essentially, 00:08:31.560 --> 00:08:34.080 you were right, I was wrong. He admits that these 00:08:34.080 --> 00:08:36.059 are reptilian and that they must belong to a 00:08:36.059 --> 00:08:39.299 previously unknown type of giant herbivore. That 00:08:39.299 --> 00:08:41.399 letter must have been framed on Mantell's wall. 00:08:41.659 --> 00:08:44.720 It was his ticket to legitimacy. It validated 00:08:44.720 --> 00:08:48.019 everything. But he still had a problem. He knew 00:08:48.019 --> 00:08:50.919 it was a giant herbivore reptile, but he didn't 00:08:50.919 --> 00:08:52.919 know what it looked like. He had no model, no 00:08:52.919 --> 00:08:56.379 blueprint. And this leads to that famous, the 00:08:56.379 --> 00:08:59.200 aha moment at the Royal College of Surgeons. 00:08:59.360 --> 00:09:03.500 The breakthrough. It's September 1824. Mantell 00:09:03.500 --> 00:09:05.840 is in London, searching through the vast collections 00:09:05.840 --> 00:09:08.379 of skeletons, trying to find a modern analog, 00:09:08.759 --> 00:09:12.220 a match. He's looking at lizards, crocodiles, 00:09:12.320 --> 00:09:14.879 turtles. Nothing matches. He's about to give 00:09:14.879 --> 00:09:16.799 up. And then someone taps him on the shoulder. 00:09:17.019 --> 00:09:20.320 Enter the unsung hero, Samuel Stutchbury. He's 00:09:20.320 --> 00:09:22.759 a young assistant curator there. He walks by, 00:09:22.919 --> 00:09:25.419 sees Mantell looking frustrated with these strange 00:09:25.419 --> 00:09:28.460 fossil teeth, and says, wait a minute. Stutchbury 00:09:28.460 --> 00:09:30.919 had just finished preparing a specimen of a modern 00:09:30.919 --> 00:09:32.519 iguana. Which would have been a pretty exotic 00:09:32.519 --> 00:09:35.019 animal in London at the time. Very. An iguana 00:09:35.019 --> 00:09:37.460 from the Caribbean or South America. Stutchbury 00:09:37.460 --> 00:09:40.120 goes to a jar or a cabinet, pulls out the iguana 00:09:40.120 --> 00:09:42.220 skull, and shows Mantell the teeth. What's the 00:09:42.220 --> 00:09:44.769 reaction? It was a perfect match. I mean, you 00:09:44.769 --> 00:09:47.490 can imagine his eyes lighting up. The shape, 00:09:47.529 --> 00:09:50.070 the serrations, the ridges, they were identical. 00:09:50.350 --> 00:09:52.570 The only difference was the size. And how big 00:09:52.570 --> 00:09:55.750 was the difference? It was massive. Mantell measured 00:09:55.750 --> 00:09:59.509 them. The fossil teeth were 20 times larger than 00:09:59.509 --> 00:10:02.149 the iguana teeth. So he does the math right there 00:10:02.149 --> 00:10:04.289 on the spot. He does the scaling. It's simple 00:10:04.289 --> 00:10:08.320 reasoning. If a modern iguana is, say, three 00:10:08.320 --> 00:10:11.259 or four feet long, and this animal is 20 times 00:10:11.259 --> 00:10:14.100 bigger. Then the animal must be 60 to 80 feet 00:10:14.100 --> 00:10:17.799 long. That was the image. A colossal, 80 -foot 00:10:17.799 --> 00:10:21.080 -long super iguana stalking the English countryside. 00:10:21.519 --> 00:10:23.500 It's terrifying. And because of that incredible 00:10:23.500 --> 00:10:25.980 resemblance, he needed a name. He toyed with 00:10:25.980 --> 00:10:29.279 iguanasaurus, right? He did. Iguana lizard. Which, 00:10:29.460 --> 00:10:31.539 if you translate iguana, which comes from the 00:10:31.539 --> 00:10:33.740 Arawak word iwana for lizard, basically means 00:10:33.740 --> 00:10:36.190 lizard lizard. A bit redundant. A little on the 00:10:36.190 --> 00:10:38.649 nose. His friend William Coney Bear, who was 00:10:38.649 --> 00:10:41.149 a clergyman and also a geologist, suggested something 00:10:41.149 --> 00:10:44.250 more elegant. He proposed iguanoids, which means 00:10:44.250 --> 00:10:48.210 iguana -like, or iguanodon. Iguana tooth. Iguana 00:10:48.210 --> 00:10:50.549 tooth. And iguanodon just rolls off the tongue 00:10:50.549 --> 00:10:52.330 better, doesn't it? It does. It has a ring to 00:10:52.330 --> 00:10:55.769 it. It does. And on February 10, 1825, Mantell 00:10:55.769 --> 00:10:58.649 formally published the paper. Iguanodon became 00:10:58.649 --> 00:11:01.769 the second dinosaur ever named, just after Buckland's 00:11:01.769 --> 00:11:04.320 megalosaurus. But again, to be clear, they aren't 00:11:04.320 --> 00:11:06.539 calling them dinosaurs yet. No, not at all. To 00:11:06.539 --> 00:11:08.879 them, they are just saurians, giant lizards. 00:11:08.919 --> 00:11:11.259 The concept of dinosauria hasn't been invented. 00:11:11.679 --> 00:11:14.539 So Mantell has his name. He has his teeth. He 00:11:14.539 --> 00:11:17.059 has his 80 -foot lizard. But then he finds the 00:11:17.059 --> 00:11:19.919 Maidstone specimen. And this is where the most 00:11:19.919 --> 00:11:23.179 famous myth of Iguanodon is born. Ah, the Maidstone 00:11:23.179 --> 00:11:26.639 slab. This is a game changer. It's found in 1834 00:11:26.639 --> 00:11:29.919 in a quarry in Kent. The owner of the quarry 00:11:29.919 --> 00:11:31.500 had it blown up with gunpowder, unfortunately. 00:11:31.840 --> 00:11:34.779 When why? just to get at the rock. Fossils were 00:11:34.779 --> 00:11:36.779 a nuisance, but Mantell managed to collect the 00:11:36.779 --> 00:11:39.500 pieces. When he puzzled them back together, he 00:11:39.500 --> 00:11:42.279 had the most complete skeleton of a large dinosaur 00:11:42.279 --> 00:11:44.759 seen anywhere in the world up to that date. It 00:11:44.759 --> 00:11:48.240 had limbs, ribs, vertebrae. Yeah. Real bones. 00:11:48.480 --> 00:11:51.080 It had a lot of the puzzle pieces, and somewhere 00:11:51.080 --> 00:11:54.340 in the middle of this jumbled block, there was 00:11:54.340 --> 00:11:59.799 a spike. A single, conical, bony spike. Now Mantell 00:11:59.799 --> 00:12:01.799 is still operating on the super iguana theory. 00:12:02.090 --> 00:12:04.549 That's his only reference point. So he looks 00:12:04.549 --> 00:12:07.649 at his modern iguana skull, specifically the 00:12:07.649 --> 00:12:10.090 rhinoceros iguana, Cichlura cornuta. What does 00:12:10.090 --> 00:12:12.570 it have on its nose? A little horn, a bump. A 00:12:12.570 --> 00:12:16.889 small, bony tubercle, a bump. So for Mantel, 00:12:16.950 --> 00:12:19.789 the logical deduction is simple. The big spike 00:12:19.789 --> 00:12:22.289 goes on the nose of his big iguana. It makes 00:12:22.289 --> 00:12:24.090 perfect sense if you assume the animal is just 00:12:24.090 --> 00:12:26.240 a scaled -up lizard. It's a completely reasonable 00:12:26.240 --> 00:12:28.740 conclusion. Completely. He placed that horn on 00:12:28.740 --> 00:12:31.919 the snout, and for the next 50 years, every drawing, 00:12:32.019 --> 00:12:34.639 every model, every scientific thought about Iguanodon 00:12:34.639 --> 00:12:37.539 featured that unicorn horn. It's such a cool 00:12:37.539 --> 00:12:40.279 image, though, the giant horned lizard. It is. 00:12:40.360 --> 00:12:42.480 But the image was about to be completely demolished. 00:12:42.480 --> 00:12:44.460 We leave the era of the lizard and enter the 00:12:44.460 --> 00:12:46.779 era of the elephant. And this shift is driven 00:12:46.779 --> 00:12:49.860 by one man, Sir Richard Owen. The villain of 00:12:49.860 --> 00:12:53.720 the piece. Or is that unfair? Let's say. The 00:12:53.720 --> 00:12:56.320 heavy handed architect. Owen was a genius, make 00:12:56.320 --> 00:12:58.659 no mistake, a brilliant anatomist, but he was 00:12:58.659 --> 00:13:01.500 also arrogant, politically savvy and deeply religious. 00:13:01.980 --> 00:13:05.159 This is the 1840s. Darwin hasn't published on 00:13:05.159 --> 00:13:08.120 the origin of species yet, but ideas of evolution, 00:13:08.340 --> 00:13:12.220 what they call transmutation. The idea that simple 00:13:12.220 --> 00:13:14.580 animals could turn into complex ones over time. 00:13:14.720 --> 00:13:18.120 Exactly. Owen hated that idea. He believed in 00:13:18.120 --> 00:13:20.899 a divinely created hierarchy of life. He wanted 00:13:20.899 --> 00:13:22.879 to show that these ancient reptiles were not 00:13:22.879 --> 00:13:26.059 primitive ancestors of modern lizards. He wanted 00:13:26.059 --> 00:13:28.220 to show they were distinct, advanced, perfect 00:13:28.220 --> 00:13:30.440 creations in their own right. So how does he 00:13:30.440 --> 00:13:33.580 use iguanodon to do that? To fight this war against 00:13:33.580 --> 00:13:36.779 transmutationism? He rebrands them. In 1842, 00:13:36.899 --> 00:13:39.539 he coins the term dinosauria, terrible lizards 00:13:39.539 --> 00:13:41.980 or fearfully great lizards, and he lumps iguanodon, 00:13:42.000 --> 00:13:44.820 megalosaurus, and hyliosaurus into this new exclusive 00:13:44.820 --> 00:13:47.820 group, but he changes their shape entirely. He 00:13:47.820 --> 00:13:50.539 takes away the sprawling lizard look. Completely. 00:13:50.700 --> 00:13:53.759 He argues that because they were so big and he 00:13:53.759 --> 00:13:56.399 actually scaled them down for Mantell's 80 feet 00:13:56.399 --> 00:13:59.320 to about 30 feet, but made them much, much bulkier, 00:13:59.460 --> 00:14:02.720 they must have had a more advanced mammal -like 00:14:02.720 --> 00:14:05.740 metabolism and posture. So he reconstructed them 00:14:05.740 --> 00:14:08.519 as pachyderms. Pachyderms. Yeah. Like elephants 00:14:08.519 --> 00:14:12.019 and rhinos. Yes. Heavy, four -legged, with pillar 00:14:12.019 --> 00:14:14.820 -like legs held directly under the body. Thick 00:14:14.820 --> 00:14:18.659 skin. Squat bodies. He basically... built a reptile 00:14:18.659 --> 00:14:21.279 skin covering over a rhinoceros skeleton, and 00:14:21.279 --> 00:14:23.120 of course he kept Mantell's nose horn. It fit 00:14:23.120 --> 00:14:25.100 the rhino look perfectly. And this brings us 00:14:25.100 --> 00:14:27.500 to the Crystal Palace. Because Owen didn't just 00:14:27.500 --> 00:14:30.710 write papers, he built a theme park. The world's 00:14:30.710 --> 00:14:32.809 first dinosaur park. It's an incredible story. 00:14:32.950 --> 00:14:34.870 It's in Sydenham Hill, South London, starting 00:14:34.870 --> 00:14:38.090 in 1852. After the Great Exhibition, the Crystal 00:14:38.090 --> 00:14:40.389 Palace building was moved there, and the company 00:14:40.389 --> 00:14:43.049 commissioned Benjamin Waterhouse Hawkins, a brilliant 00:14:43.049 --> 00:14:45.450 sculptor, to build life -size models of these 00:14:45.450 --> 00:14:48.289 antediluvian beasts. And Owen was the scientific 00:14:48.289 --> 00:14:50.590 consultant. Owen directed every single detail. 00:14:50.789 --> 00:14:52.429 They're still there. You can go see them today. 00:14:52.610 --> 00:14:54.990 They are. A bit weathered. But they're there. 00:14:55.440 --> 00:14:57.059 And you'll see the iguanodons. There are two 00:14:57.059 --> 00:14:59.519 of them. One is standing. One is resting on its 00:14:59.519 --> 00:15:03.179 belly. And they look like giant, scaly bulldogs. 00:15:03.399 --> 00:15:07.399 They are massive, lumbering, rhino -like tanks. 00:15:07.720 --> 00:15:09.759 And the confidence of these Victorian scientists, 00:15:10.019 --> 00:15:12.899 they were so sure they were right that they held 00:15:12.899 --> 00:15:15.250 a party inside one of the models. The dinner 00:15:15.250 --> 00:15:17.389 in the Iguanodon, this is legendary stuff. It's 00:15:17.389 --> 00:15:21.070 New Year's Eve, 1853. The mold for the standing 00:15:21.070 --> 00:15:23.190 Iguanodon was finished, but they hadn't poured 00:15:23.190 --> 00:15:25.769 the concrete yet, so it was a giant hollow shell. 00:15:26.029 --> 00:15:28.169 So they just set up a table inside. Literally 00:15:28.169 --> 00:15:30.769 inside the belly of the beast. Owen, the guest 00:15:30.769 --> 00:15:33.259 of honor, sits at the head of the table. which 00:15:33.259 --> 00:15:35.259 is physically located up inside the dinosaur's 00:15:35.259 --> 00:15:38.039 head, and 20 other prominent men of science in 00:15:38.039 --> 00:15:40.340 the press sit down the length of the body. Wait, 00:15:40.399 --> 00:15:42.580 20 people? Was it that big? It was tight. Some 00:15:42.580 --> 00:15:44.799 reports say 21 people. They had to sit very close. 00:15:45.100 --> 00:15:47.620 But can you imagine the scene? It's dark. It's 00:15:47.620 --> 00:15:50.580 illuminated by lanterns. They are in formal Victorian 00:15:50.580 --> 00:15:53.240 evening wear tailcoats, cravats. And they're 00:15:53.240 --> 00:15:55.720 eating a multi -course meal inside a dinosaur. 00:15:56.179 --> 00:15:58.159 Raising a toast to the queen and to Professor 00:15:58.159 --> 00:16:01.480 Owen, it was a PR masterstroke. It was a declaration 00:16:01.480 --> 00:16:04.190 to the public. We have conquered the past. We 00:16:04.190 --> 00:16:06.389 know exactly what these things were. Little did 00:16:06.389 --> 00:16:09.509 they know they were eating dinner inside a magnificent 00:16:09.509 --> 00:16:12.389 mistake. A truly magnificent mistake. Because 00:16:12.389 --> 00:16:15.870 while Owen was dining in London, the real Iguanodon 00:16:15.870 --> 00:16:18.690 was waiting to be found. And it wasn't in a forest 00:16:18.690 --> 00:16:23.259 or a quarry. It was deep. deep underground. So 00:16:23.259 --> 00:16:25.919 let's go to Belgium. The year is 1878. We're 00:16:25.919 --> 00:16:27.519 in the village of Bernassart, right near the 00:16:27.519 --> 00:16:30.240 French border. This is coal country. The Industrial 00:16:30.240 --> 00:16:33.200 Revolution is hungry for fuel. We're at the Sambarb 00:16:33.200 --> 00:16:35.440 Colliery. And how deep are we talking? We are 00:16:35.440 --> 00:16:38.379 322 meters down. That's over a thousand feet. 00:16:38.539 --> 00:16:42.000 So this is dark, damp, dangerous work. Extremely. 00:16:42.429 --> 00:16:45.129 Two miners, Jules Créter and Alphonse Blanchard, 00:16:45.289 --> 00:16:47.590 are following a coal seam called the Luron seam. 00:16:48.129 --> 00:16:50.110 Suddenly, the coal just runs out. They hit a 00:16:50.110 --> 00:16:52.649 pocket of clay. This is bad news for miners. 00:16:52.750 --> 00:16:55.049 Clay is unstable. It can cause collapses. But 00:16:55.049 --> 00:16:57.090 they see something in the clay. They see these 00:16:57.090 --> 00:17:01.169 shiny black chunks, pyrite, fool's gold. At first, 00:17:01.169 --> 00:17:02.730 they think, well, at least we found some gold. 00:17:02.870 --> 00:17:05.430 But mixed in with the pyrite are these large, 00:17:05.549 --> 00:17:09.130 hard, log -like things. They assume it's petrified 00:17:09.130 --> 00:17:11.069 wood, old tree trunks. Which makes sense in a 00:17:11.069 --> 00:17:13.690 coal mine. Coal is just old plants. Exactly. 00:17:14.029 --> 00:17:16.609 So they take a pickaxe to one of the logs to 00:17:16.609 --> 00:17:18.730 clear it out of the way. They chop through it 00:17:18.730 --> 00:17:20.910 and bring the pieces up to the surface. The mine 00:17:20.910 --> 00:17:23.410 managers look at it and realize, this isn't wood, 00:17:23.490 --> 00:17:25.849 this is bone. So they call in the cavalry. They 00:17:25.849 --> 00:17:28.089 contact the Royal Museum of Natural History in 00:17:28.089 --> 00:17:30.089 Brussels, and what they find when they get there 00:17:30.089 --> 00:17:32.680 is... It's just staggering. It wasn't just a 00:17:32.680 --> 00:17:35.099 bone or two. It was a fissure, a sinkhole essentially, 00:17:35.400 --> 00:17:37.720 that filled with clay millions of years ago. 00:17:37.859 --> 00:17:40.940 And inside that clay were skeletons. Skeletons, 00:17:40.980 --> 00:17:44.180 plural. Dozens. Over the next three years, Louis 00:17:44.180 --> 00:17:47.160 Lepow and his team excavated at least 38 individuals. 00:17:47.579 --> 00:17:50.640 Most of them were full -grown adults. And unlike 00:17:50.640 --> 00:17:53.299 the Maidstone slab, these weren't jumbled. They 00:17:53.299 --> 00:17:55.839 were articulated. Every bone in place. From the 00:17:55.839 --> 00:17:58.140 tip of the nose to the end of the tail, perfect 00:17:58.140 --> 00:18:01.019 three -dimensional skeletons. This transforms 00:18:01.019 --> 00:18:03.000 the field overnight. You can't overstate the 00:18:03.000 --> 00:18:04.720 importance of this. It's the difference between 00:18:04.720 --> 00:18:07.180 having a few crumpled pages of a book and having 00:18:07.180 --> 00:18:09.759 the entire encyclopedia suddenly appear. But 00:18:09.759 --> 00:18:13.119 then tragedy strikes. Or, uh, chemistry strikes. 00:18:13.319 --> 00:18:16.779 The pyrite disease. Yes, the curse of Berna Sartre. 00:18:17.720 --> 00:18:19.279 You see, these bones have been sitting in red, 00:18:19.440 --> 00:18:23.200 oxygen -free clay for 125 million years. The 00:18:23.200 --> 00:18:25.500 groundwater there was rich in iron and sulfur. 00:18:25.779 --> 00:18:29.420 Over eons, pyrite crystals, that's iron sulfide, 00:18:29.519 --> 00:18:31.980 had formed inside the microscopic pores of the 00:18:31.980 --> 00:18:34.220 bone. So the bones were literally infused with 00:18:34.220 --> 00:18:36.559 fool's gold. Partially, yes. And underground, 00:18:36.759 --> 00:18:39.059 that's fine. Pyrite is stable without oxygen. 00:18:39.359 --> 00:18:42.099 But the moment they brought those bones up 322 00:18:42.099 --> 00:18:44.599 meters into the fresh air... The oxygen hits 00:18:44.599 --> 00:18:47.390 them. And the humidity changes. Pyrite reacts 00:18:47.390 --> 00:18:49.970 with oxygen and water to form iron sulfate and 00:18:49.970 --> 00:18:52.829 sulfuric acid. This chemical reaction causes 00:18:52.829 --> 00:18:55.170 the crystals to expand dramatically. An expansion 00:18:55.170 --> 00:18:57.759 inside a fossil bone sounds really bad. It's 00:18:57.759 --> 00:19:00.339 catastrophic. The bones started to crack. Then 00:19:00.339 --> 00:19:02.619 they started to swell and crumble. Then they 00:19:02.619 --> 00:19:05.900 would literally turn to gray dust. The preparators 00:19:05.900 --> 00:19:07.900 in Brussels would finish cleaning a beautiful 00:19:07.900 --> 00:19:10.259 vertebra, go home for the night, and come back 00:19:10.259 --> 00:19:12.279 the next morning to find a pile of powder on 00:19:12.279 --> 00:19:14.640 the table. They were losing the greatest fossil 00:19:14.640 --> 00:19:17.019 discovery in history as they were unearthing 00:19:17.019 --> 00:19:20.750 it. It was a full -blown panic. Louis Dupas deserves 00:19:20.750 --> 00:19:23.369 a medal for what he did. He turned the entire 00:19:23.369 --> 00:19:27.109 lab into a scientific triage unit. He experimented 00:19:27.109 --> 00:19:29.809 with everything. Finally, he developed a method. 00:19:30.009 --> 00:19:32.890 What did he do? He submerged the bones in a boiling 00:19:32.890 --> 00:19:36.109 vat of animal gelatin mixed with oil of cloves. 00:19:36.490 --> 00:19:39.130 Oil of cloves? What was that for? It's a natural 00:19:39.130 --> 00:19:42.380 fungicide and preservative. The hot gelatin would 00:19:42.380 --> 00:19:44.799 seep into the pores and seal the pyrite off from 00:19:44.799 --> 00:19:48.079 the air. Then he would wrap the bones in tinfoil 00:19:48.079 --> 00:19:51.319 to seal them completely. It was messy, dangerous 00:19:51.319 --> 00:19:54.259 work, but it arrested the decay for a few decades. 00:19:54.599 --> 00:19:57.400 I read that in the 1930s, they tried to fix them 00:19:57.400 --> 00:20:00.250 again with a new method. Yeah, and that was a 00:20:00.250 --> 00:20:02.569 complete disaster. They tried to use alcohol 00:20:02.569 --> 00:20:05.349 and shellac, but they didn't dry the bones enough 00:20:05.349 --> 00:20:08.690 first. The shellac formed a hard, impermeable 00:20:08.690 --> 00:20:11.150 seal on the outside, but it trapped moisture 00:20:11.150 --> 00:20:14.650 inside. Oh no. So the disease flared up again 00:20:14.650 --> 00:20:18.190 inside the shellac casing, destroying the bones 00:20:18.190 --> 00:20:20.990 from the inside out. Oh, terrible mistake. It 00:20:20.990 --> 00:20:22.589 wasn't until recently we actually figured it 00:20:22.589 --> 00:20:25.079 out. Yeah, now we use things like polyethylene 00:20:25.079 --> 00:20:27.619 glycol and keep the most fragile specimens in 00:20:27.619 --> 00:20:30.259 climate -controlled glass cases with vacuum pumps 00:20:30.259 --> 00:20:33.019 to remove all the oxygen. But the fact that we 00:20:33.019 --> 00:20:35.380 have them at all is a miracle of 19th century 00:20:35.380 --> 00:20:38.400 conservation. So, thanks to DePauw, we have the 00:20:38.400 --> 00:20:41.099 bones. Now we need to put them together. And 00:20:41.099 --> 00:20:43.500 to Louis Dullo. Louis Dullo. He is the man who 00:20:43.500 --> 00:20:46.180 killed the rhino. He was put in charge of studying 00:20:46.180 --> 00:20:48.059 and mounting these skeletons, and he looked at 00:20:48.059 --> 00:20:50.720 these 38 skeletons and immediately saw that Richard 00:20:50.720 --> 00:20:52.839 Owen was completely wrong. What was the dead 00:20:52.839 --> 00:20:56.039 giveaway? The limbs. The front legs were significantly 00:20:56.039 --> 00:20:58.519 shorter and more slender than the powerful hind 00:20:58.519 --> 00:21:01.859 legs. A rhino has legs of roughly equal length 00:21:01.859 --> 00:21:04.880 and strength. This animal had the build of... 00:21:04.880 --> 00:21:07.720 Well, Dalla looked to Australia. It had the build 00:21:07.720 --> 00:21:10.279 of a kangaroo. So we leave the elephant era and 00:21:10.279 --> 00:21:13.289 enter the kangaroo era. The tripod era. Dallow 00:21:13.289 --> 00:21:15.789 concluded that a guanodon was primarily a biped. 00:21:15.869 --> 00:21:18.130 It walked on its hind legs. So he designed this 00:21:18.130 --> 00:21:20.309 amazing mount, which you can still see in Brussels 00:21:20.309 --> 00:21:23.450 today, where the animal stands bolt upright, 00:21:23.630 --> 00:21:26.690 vertical spine, head 20 feet in there. And the 00:21:26.690 --> 00:21:29.009 tail. What did he do with the tail? Dragging 00:21:29.009 --> 00:21:31.289 on the ground, it forms the third leg of a tripod. 00:21:31.549 --> 00:21:34.250 It's the classic Godzilla posture that dominated 00:21:34.250 --> 00:21:37.670 monster movies for 50 years. And the horn. The 00:21:37.670 --> 00:21:40.410 famous nose horn. The horn. This is the moment 00:21:40.410 --> 00:21:43.369 of truth. With a complete articulated skeleton, 00:21:43.730 --> 00:21:45.690 Dallow looked at the nose. There was no spike, 00:21:45.890 --> 00:21:48.430 no bump, nothing. And he looked at the hand. 00:21:48.650 --> 00:21:51.750 And there it was, on the thumb, digit one, a 00:21:51.750 --> 00:21:54.329 massive conical spike sticking out of the wrist. 00:21:54.650 --> 00:21:57.009 Mantell's nose horn was a thumb spike all along. 00:21:57.210 --> 00:21:59.289 It's one of those truth is stranger than fiction 00:21:59.289 --> 00:22:02.190 moments in science. It's just incredible. So 00:22:02.190 --> 00:22:04.720 Dallow got the thumb right. He corrected the 00:22:04.720 --> 00:22:07.299 biggest mistake. He got the bipedalism partially 00:22:07.299 --> 00:22:10.180 right. But he got the tail wrong. He got the 00:22:10.180 --> 00:22:12.279 tail very wrong. And this is the controversial 00:22:12.279 --> 00:22:15.900 part. He probably knew it. What do you mean he 00:22:15.900 --> 00:22:18.079 knew it? The fossils were preserved with something 00:22:18.079 --> 00:22:20.460 called ossified tendons. These are ligaments 00:22:20.460 --> 00:22:22.900 that have turned to bone. They ran along the 00:22:22.900 --> 00:22:25.619 top of the spine and way down the tail. They 00:22:25.619 --> 00:22:29.259 formed a stiff... bony lattice, like a trellis. 00:22:29.539 --> 00:22:31.680 What does that do mechanically for the animal? 00:22:31.859 --> 00:22:35.099 It turns the tail into a stiff rod. A plank. 00:22:35.279 --> 00:22:38.240 You cannot bend a plank. But to make the Iguanodon 00:22:38.240 --> 00:22:40.700 stand up like a kangaroo, with that S -curve 00:22:40.700 --> 00:22:44.059 in its back, Dalo had to bend the tail. So what 00:22:44.059 --> 00:22:46.200 did he do with the museum mount? In the mount, 00:22:46.299 --> 00:22:48.559 he physically broke the connection between the 00:22:48.559 --> 00:22:51.420 tail vertebrae to create that curve. He forced 00:22:51.420 --> 00:22:54.420 the bones to fit his theory. He assumed it had 00:22:54.420 --> 00:22:56.500 to be like a wallaby, so he made it a wallaby, 00:22:56.619 --> 00:22:59.000 even if the bones themselves complained. That's 00:22:59.000 --> 00:23:01.099 a huge cautionary tale for science right there. 00:23:01.200 --> 00:23:04.400 It is. Don't force the data to fit the hypothesis. 00:23:05.180 --> 00:23:09.400 But that image. The upright, tail -dragging Iguanodon 00:23:09.400 --> 00:23:12.900 dominated the world for a century. It's the Iguanodon 00:23:12.900 --> 00:23:15.359 in the original King Kong. It's the Iguanodon 00:23:15.359 --> 00:23:18.079 in children's books until the 1980s. So when 00:23:18.079 --> 00:23:20.599 did we finally fix the tail? That came with the 00:23:20.599 --> 00:23:23.420 dinosaur renaissance, the late 60s, 70s, and 00:23:23.420 --> 00:23:26.519 80s. Scientists like John Ostrom and Robert Baker 00:23:26.519 --> 00:23:29.200 started arguing that dinosaurs were active and 00:23:29.200 --> 00:23:32.660 dynamic, not sluggish lizards. And a paleontologist 00:23:32.660 --> 00:23:35.140 named David Norman took a fresh look at the Bernassart 00:23:35.140 --> 00:23:37.599 specimens. And Norman said, Unbreak the tail. 00:23:37.819 --> 00:23:40.140 Essentially. He realized that the stiff tail 00:23:40.140 --> 00:23:42.380 acted as a counterbalance. Think of it like a 00:23:42.380 --> 00:23:45.059 seesaw. The hips are the fulcrum. The heavy tail 00:23:45.059 --> 00:23:47.339 on one side balances the heavy chest and head 00:23:47.339 --> 00:23:49.680 on the other. This means the animal held its 00:23:49.680 --> 00:23:52.519 body horizontally. A flat back, parallel to the 00:23:52.519 --> 00:23:54.740 ground. Right. No dragging the tail. That would 00:23:54.740 --> 00:23:56.940 be physically impossible with those tendons locking 00:23:56.940 --> 00:23:59.019 the vertebrae together. The tail was held straight 00:23:59.019 --> 00:24:00.640 out behind it. And this must have completely 00:24:00.640 --> 00:24:03.039 changed how we viewed its movement. Completely. 00:24:03.180 --> 00:24:05.619 And Norman also did a really deep dive into the 00:24:05.619 --> 00:24:07.839 hands. And this brings us to our modern view, 00:24:08.039 --> 00:24:11.259 the Swiss army knife hand. I love this description 00:24:11.259 --> 00:24:13.480 because the hand of a guanodon is just plain 00:24:13.480 --> 00:24:17.099 weird. It's not like anything alive today. It's 00:24:17.099 --> 00:24:19.480 a specialized multi -tool. It's fantastic. Let's 00:24:19.480 --> 00:24:21.480 break it down digit by digit. Okay, digit one. 00:24:21.660 --> 00:24:24.950 The thumb. The spike. Originally the nose horn. 00:24:25.069 --> 00:24:27.130 We now know it sits on the wrist and it probably 00:24:27.130 --> 00:24:29.230 pointed inward and sideways. What is it for? 00:24:29.269 --> 00:24:32.130 Opening cans? The can opener theory was actually 00:24:32.130 --> 00:24:34.029 proposed that it was for breaking open tough 00:24:34.029 --> 00:24:37.250 seeds or fruit. But the biomechanics, the way 00:24:37.250 --> 00:24:39.109 the muscles would have worked, strongly suggest 00:24:39.109 --> 00:24:42.549 it was a weapon. A shiv. A stiletto. A close 00:24:42.549 --> 00:24:45.769 quarters defensive weapon. If a predator, say 00:24:45.769 --> 00:24:48.589 a neovanator or a baryonyx attacks, a granadon 00:24:48.589 --> 00:24:51.069 can use that spike to inflict a devastating puncture 00:24:51.069 --> 00:24:54.380 wound. Aim for the eyes, the neck, the soft belly. 00:24:54.579 --> 00:24:57.099 It wasn't a slashing weapon. It was a stabbing 00:24:57.099 --> 00:24:59.940 weapon. That is brutal. Okay, digits two, three, 00:25:00.019 --> 00:25:02.930 and four. Middle fingers. These are the strangest 00:25:02.930 --> 00:25:05.190 fingers in the dinosaur world. They are grouped 00:25:05.190 --> 00:25:07.809 together, they are really robust, and the claws 00:25:07.809 --> 00:25:10.549 aren't sharp hooks like you'd expect. They are 00:25:10.549 --> 00:25:13.289 flattened and hoof -like. Hose on fingers, that's 00:25:13.289 --> 00:25:16.049 bizarre. Exactly. And the wrist bones are all 00:25:16.049 --> 00:25:18.109 interlocked so they can't rotate or flex much. 00:25:18.410 --> 00:25:20.650 This means these three middle fingers were designed 00:25:20.650 --> 00:25:24.970 for one thing, to bear weight. Iguanodon walked 00:25:24.970 --> 00:25:27.549 on its hands. So it wasn't a biped after all. 00:25:27.710 --> 00:25:30.089 It was what we call a facultative biped. This 00:25:30.089 --> 00:25:32.990 is the alter... terrain vehicle concept. When 00:25:32.990 --> 00:25:35.230 it was grazing or just moving slowly, it was 00:25:35.230 --> 00:25:37.809 quadruped. It walked on all fours on those three 00:25:37.809 --> 00:25:40.569 middle fingers. Okay. But because the front legs 00:25:40.569 --> 00:25:42.329 were shorter than the back legs, if it needed 00:25:42.329 --> 00:25:44.309 to run or if it needed to reach high leaves on 00:25:44.309 --> 00:25:47.069 a tree, it could shift its weight back and stand 00:25:47.069 --> 00:25:49.670 up running on its hind legs. That is incredibly 00:25:49.670 --> 00:25:52.470 versatile. It's the best of both worlds. It has 00:25:52.470 --> 00:25:54.769 the stability of a quadruped for low browsing 00:25:54.769 --> 00:25:57.450 and the reach and potential speed of a biped 00:25:57.450 --> 00:25:59.450 when it needed it. Okay. So that just leaves 00:25:59.450 --> 00:26:02.950 digit five. The pinky? The pinky is the odd one 00:26:02.950 --> 00:26:05.430 out. It hangs off to the side of the weight -bearing 00:26:05.430 --> 00:26:09.230 hoof. It's long, it's slender, and it has extra 00:26:09.230 --> 00:26:12.009 joints that make it very flexible. Prehensile. 00:26:12.009 --> 00:26:15.230 Could it grab things? Effectively, yes. While 00:26:15.230 --> 00:26:17.289 the thumb stabs and the middle fingers walk, 00:26:17.470 --> 00:26:20.069 the pinky grabs. It could wrap around branches 00:26:20.069 --> 00:26:23.670 and pull vegetation toward the mouth. Stab, walk, 00:26:23.910 --> 00:26:27.549 grab. Three distinct functions in one hand. It's 00:26:27.549 --> 00:26:31.059 evolutionary genius. It explains why Iguanodon 00:26:31.059 --> 00:26:33.380 and its relatives were so incredibly successful 00:26:33.380 --> 00:26:36.480 for so long. They could handle almost any situation. 00:26:36.859 --> 00:26:38.880 Let's talk about the mouth. Because if you're 00:26:38.880 --> 00:26:41.680 a giant herbivore, your main job is eating. And 00:26:41.680 --> 00:26:43.819 Iguanodon had a very high -tech way of chewing. 00:26:44.019 --> 00:26:46.559 It did. And this goes back to that old reptiles 00:26:46.559 --> 00:26:49.119 don't chew bias. Mammals chew by moving their 00:26:49.119 --> 00:26:51.500 jaw side to side like a cow or in a rotary motion. 00:26:51.759 --> 00:26:54.819 Most reptile jaws just hinge open and shut. So 00:26:54.819 --> 00:26:57.119 how do you grind tough plants with a simple hinge? 00:26:57.529 --> 00:27:00.029 You invent something called pleurokinesis. Unpack 00:27:00.029 --> 00:27:02.529 that word for us. Pleurokinesis. It means side 00:27:02.529 --> 00:27:05.349 movement. The upper jaw bones of iguanodon, the 00:27:05.349 --> 00:27:07.509 maxillae, weren't fused solid to the rest of 00:27:07.509 --> 00:27:09.329 the skull. They had a mobile joint connecting 00:27:09.329 --> 00:27:11.829 them. The upper jaw was mobile. It could flex. 00:27:12.349 --> 00:27:15.029 When iguanodon bit down, the pressure of the 00:27:15.029 --> 00:27:17.549 lower teeth hitting the upper teeth forced the 00:27:17.549 --> 00:27:20.470 upper jaw bones to bow outwards. away from the 00:27:20.470 --> 00:27:22.809 skull so its head got wider as it chewed the 00:27:22.809 --> 00:27:25.450 cheeks pushed out just a little as the upper 00:27:25.450 --> 00:27:28.369 teeth slid outward they would grind against the 00:27:28.369 --> 00:27:31.490 inner surface of the lower teeth it created a 00:27:31.490 --> 00:27:34.309 powerful shearing and grinding action without 00:27:34.309 --> 00:27:37.009 the lower jaw needing to dislocate or move side 00:27:37.009 --> 00:27:40.930 to side that is wild a flexing skull It was a 00:27:40.930 --> 00:27:44.130 very efficient way to process very tough vegetation. 00:27:44.410 --> 00:27:47.670 We're talking horsetails, cycads, conifers, things 00:27:47.670 --> 00:27:49.269 that would be really hard to break down otherwise. 00:27:49.730 --> 00:27:52.529 And this brings us to the Gardner theory of their 00:27:52.529 --> 00:27:55.309 ecological role. I love this one. The idea that 00:27:55.309 --> 00:27:57.990 Iguanodon changed the world just by eating. Think 00:27:57.990 --> 00:28:00.390 about the early Cretaceous landscape. The world 00:28:00.390 --> 00:28:03.539 is dominated by gymnosperms. These are slow -growing 00:28:03.539 --> 00:28:06.740 plants like conifers, ferns, and cycads. Then, 00:28:06.859 --> 00:28:09.680 iguanodon appears in huge numbers. It's a low 00:28:09.680 --> 00:28:11.940 -browser. It's a super -efficient lawnmower. 00:28:12.099 --> 00:28:14.759 It clears the brush. It devastates the slow -growing 00:28:14.759 --> 00:28:17.740 plants at ground level. By constantly clearing 00:28:17.740 --> 00:28:20.619 that understory, it creates a disturbance. And 00:28:20.619 --> 00:28:24.160 who loves a disturbed environment? Weeds. Fast 00:28:24.160 --> 00:28:26.400 -growing, opportunistic plants. Exactly. And 00:28:26.400 --> 00:28:29.119 who are the new kids on the block in the Cretaceous, 00:28:29.119 --> 00:28:32.349 botanically speaking? Angiosperms. Flowering 00:28:32.349 --> 00:28:34.910 plants. They are the fast -growing weeds of the 00:28:34.910 --> 00:28:37.650 dinosaur era. There is a very strong hypothesis 00:28:37.650 --> 00:28:42.349 that the intense grazing pressure from huge herds 00:28:42.349 --> 00:28:45.190 of Iguanodon and its relatives helped clear the 00:28:45.190 --> 00:28:47.650 way for the evolutionary explosion of flowering 00:28:47.650 --> 00:28:49.809 plants. So we might have roses and apple trees 00:28:49.809 --> 00:28:52.210 today because Iguanodon ate all the ferns. It's 00:28:52.210 --> 00:28:54.309 a distinct possibility. There are ecosystem engineers 00:28:54.309 --> 00:28:56.809 on a massive scale. We've talked about the animal 00:28:56.809 --> 00:28:58.670 itself. Let's talk about the family tree. Because 00:28:58.670 --> 00:29:00.609 for a long time, it seems like if you found a 00:29:00.609 --> 00:29:03.970 generic Big herbivore bone. You just slap the 00:29:03.970 --> 00:29:07.349 label iguanodon on it. Ah, the wastebasket taxon. 00:29:07.349 --> 00:29:09.950 A classic problem in paleontology. Explain that 00:29:09.950 --> 00:29:12.630 term. It's exactly what it sounds like. In taxonomy, 00:29:12.789 --> 00:29:14.890 sometimes you have a genus that becomes a dumping 00:29:14.890 --> 00:29:18.390 ground for poorly understood fossils. For over 00:29:18.390 --> 00:29:21.769 a century, if you found a big ornithopod, a bird 00:29:21.769 --> 00:29:23.930 -hipped dinosaur, that wasn't clearly something 00:29:23.930 --> 00:29:26.589 else. Scientists would just say, eh, looks kind 00:29:26.589 --> 00:29:28.410 of like an iguanodon. Let's call it iguanodon. 00:29:28.490 --> 00:29:31.430 So we ended up with iguanodon in England, iguanodon 00:29:31.430 --> 00:29:34.680 in America, iguanodon in Mongolia. It was a mess. 00:29:34.819 --> 00:29:37.579 It created this illusion of a single, globe -trotting 00:29:37.579 --> 00:29:40.940 genus, but it obscured the real diversity. In 00:29:40.940 --> 00:29:43.240 the early 2000s, researchers started the Great 00:29:43.240 --> 00:29:45.480 Cleanup. They went back and looked at all these 00:29:45.480 --> 00:29:48.079 supposed iguanodon species and realized most 00:29:48.079 --> 00:29:50.180 of them were completely different animals. So 00:29:50.180 --> 00:29:52.460 they broke them up into new genera? Yes. The 00:29:52.460 --> 00:29:54.839 American one from South Dakota became dicotodon. 00:29:54.980 --> 00:29:57.200 The lighter English one became mantellosaurus. 00:29:57.640 --> 00:30:00.640 Others became beryllium or hypsilospinus. The 00:30:00.640 --> 00:30:03.259 wastebasket was finally being sorted out. And 00:30:03.259 --> 00:30:05.220 what happened to the original, the very first 00:30:05.220 --> 00:30:07.660 tooth that Mantell found? This is the ultimate 00:30:07.660 --> 00:30:10.900 irony. The tooth that started it all, the species 00:30:10.900 --> 00:30:14.339 Iguanodon anglicus, is now considered a gnomon 00:30:14.339 --> 00:30:17.920 dubium, a dubious name. Why? It was the first. 00:30:18.039 --> 00:30:20.299 Because a single tooth isn't diagnostic enough. 00:30:20.460 --> 00:30:23.200 You can't reliably distinguish it from the teeth 00:30:23.200 --> 00:30:26.220 of Mantellosaurus or Beryllium. There are no 00:30:26.220 --> 00:30:29.140 unique features. So technically, the original 00:30:29.140 --> 00:30:32.039 Iguanodon isn't a valid species anymore. But 00:30:32.039 --> 00:30:33.799 we still use the name Iguanodon, so how does 00:30:33.799 --> 00:30:37.019 that work? We do. To save the famous name from 00:30:37.019 --> 00:30:39.480 disappearing, the International Commission on 00:30:39.480 --> 00:30:43.000 Zoological Nomenclature, the ICZN, made a special 00:30:43.000 --> 00:30:45.859 ruling. They agreed to change the type species. 00:30:46.259 --> 00:30:48.559 They swapped it. They swapped the original English 00:30:48.559 --> 00:30:51.839 tooth for the beautiful Belgian skeletons. So 00:30:51.839 --> 00:30:54.319 now, the official standard for what makes an 00:30:54.319 --> 00:30:56.759 Iguanodon an Iguanodon is the animal from the 00:30:56.759 --> 00:30:59.519 coal mine. Negronodon bernsartensis. And there 00:30:59.519 --> 00:31:01.759 was some justice for Gideon Mantell in this big 00:31:01.759 --> 00:31:03.839 taxonomic breakup, right? There was. A really 00:31:03.839 --> 00:31:06.119 nice bit of poetic justice. Remember the maidstone 00:31:06.119 --> 00:31:08.640 specimen? The one with the nose horn spike? The 00:31:08.640 --> 00:31:10.700 one Mantell called his mantelpiece. That's the 00:31:10.700 --> 00:31:13.500 one. The paleontologist Gregory Paul re -examined 00:31:13.500 --> 00:31:16.180 it in the 2000s and realized it was much lighter 00:31:16.180 --> 00:31:19.079 and more grassy than the big bulky Belgian beasts. 00:31:19.359 --> 00:31:22.099 It was a different animal entirely. So he gave 00:31:22.099 --> 00:31:25.039 it a new name. Mantellosaurus. That's a fantastic 00:31:25.039 --> 00:31:27.740 tribute. It is. So now we know that the Iguanodons 00:31:27.740 --> 00:31:30.960 of early Cretaceous Europe were actually a diverse 00:31:30.960 --> 00:31:34.099 community of different related species, some 00:31:34.099 --> 00:31:37.079 big and bulky like Iguanodon, some lighter and 00:31:37.079 --> 00:31:39.480 faster like Mantellosaurus. Speaking of community, 00:31:39.640 --> 00:31:42.200 let's talk behavior. Did they live in herds? 00:31:42.279 --> 00:31:44.880 The Bernassart mine certainly suggests they did, 00:31:44.960 --> 00:31:47.460 but with a major caveat. We used to think the 00:31:47.460 --> 00:31:49.740 mine was a snapshot of a single herd that fell 00:31:49.740 --> 00:31:53.079 into a ravine together. A Pompeii moment. A single 00:31:53.079 --> 00:31:56.980 catastrophe. And now... More detailed geological 00:31:56.980 --> 00:31:59.099 analysis suggests it might have been an accumulation 00:31:59.099 --> 00:32:01.740 over a longer period of time. Maybe a few years, 00:32:01.799 --> 00:32:03.900 maybe decades. It could have been a treacherous 00:32:03.900 --> 00:32:06.700 marsh where animals got stuck periodically. Or 00:32:06.700 --> 00:32:09.140 a river bend where carcasses washed up after 00:32:09.140 --> 00:32:11.839 floods. So the mine itself doesn't prove they 00:32:11.839 --> 00:32:13.950 walked together in life. But the footprints do. 00:32:14.109 --> 00:32:16.690 The footprints are the smoking gun. We have trackway 00:32:16.690 --> 00:32:19.109 sites, especially in Germany and England, where 00:32:19.109 --> 00:32:21.230 you see the tracks of multiple animals of the 00:32:21.230 --> 00:32:23.930 same species all walking side by side in the 00:32:23.930 --> 00:32:26.549 same direction at the same speed. That is definitive 00:32:26.549 --> 00:32:29.390 herding behavior. And those footprints connect 00:32:29.390 --> 00:32:32.859 us all the way back to the start. The pre -dinosaur 00:32:32.859 --> 00:32:36.559 era of discovery. The giant birds. Right. It 00:32:36.559 --> 00:32:39.799 all comes full circle. In the early 1800s, before 00:32:39.799 --> 00:32:43.059 Mantell even found his tooth, people were finding 00:32:43.059 --> 00:32:46.519 these massive three -toed tracks in the sandstone 00:32:46.519 --> 00:32:48.720 of the Weald. They look like giant turkey tracks, 00:32:48.920 --> 00:32:51.240 but, you know, 20 inches wide. They thought they 00:32:51.240 --> 00:32:53.720 were made by giant biblical ravens. Or other 00:32:53.720 --> 00:32:56.000 monstrous birds sent by Noah during the flood. 00:32:56.559 --> 00:32:59.119 It wasn't until we found a complete Iguanodon 00:32:59.119 --> 00:33:02.220 foot skeleton that we realized. Iguanodon walked 00:33:02.220 --> 00:33:04.779 on its toes, what we call digitigrade, just like 00:33:04.779 --> 00:33:07.440 a bird. The three weight -bearing toes matched 00:33:07.440 --> 00:33:09.640 the tracks perfectly. It's amazing how every 00:33:09.640 --> 00:33:12.019 single piece of evidence, the teeth, the spike, 00:33:12.140 --> 00:33:14.680 the tracks, the bones, was misunderstood at first 00:33:14.680 --> 00:33:16.960 and then clarified later. That's the theme of 00:33:16.960 --> 00:33:19.059 this whole story. It's a 200 -year -long process 00:33:19.059 --> 00:33:22.099 of correction. So let's talk pop culture. Iguanodon 00:33:22.099 --> 00:33:24.099 is everywhere, even if the people don't always 00:33:24.099 --> 00:33:26.559 realize it. It's the everyman dinosaur. It's 00:33:26.559 --> 00:33:29.759 not as flashy as a T -Rex or as weird as a Triceratops. 00:33:29.759 --> 00:33:32.980 It's the solid, reliable citizen of the Mesozoic. 00:33:33.019 --> 00:33:35.920 It inspired Godzilla. The original Japanese Godzilla 00:33:35.920 --> 00:33:39.500 design from 1954 was a mashup. They took the 00:33:39.500 --> 00:33:41.960 scales and plates of a Stegosaurus, the head 00:33:41.960 --> 00:33:45.400 of a T -Rex, but the body and posture, that upright 00:33:45.400 --> 00:33:47.859 tripod stance, the heavy thighs, the dragging 00:33:47.859 --> 00:33:51.359 tail, that was pure Louis Dolo Granadon. And 00:33:51.359 --> 00:33:53.859 Disney's dinosaur. The movie of the main character, 00:33:54.039 --> 00:33:56.220 Aladar. A great depiction, actually, for its 00:33:56.220 --> 00:33:58.859 time. Aladar. They gave him lips so he could 00:33:58.859 --> 00:34:01.460 talk, which is scientifically debatable. A little 00:34:01.460 --> 00:34:03.759 bit. But they captured the bulk. They captured 00:34:03.759 --> 00:34:05.900 the use of the thumb spike for defense. And they 00:34:05.900 --> 00:34:08.300 really captured the idea of them moving in large 00:34:08.300 --> 00:34:11.079 social herds. And you can't forget Arthur Conan 00:34:11.079 --> 00:34:14.139 Doyle. The Lost World. Absolutely not. You can't 00:34:14.139 --> 00:34:16.820 have a Victorian dinosaur story without Iguanodon. 00:34:16.960 --> 00:34:19.460 It represents that initial thrilling discovery 00:34:19.460 --> 00:34:22.440 of a lost prehistoric world. So as we wrap up 00:34:22.440 --> 00:34:25.179 this deep dive, what is the big takeaway? Why 00:34:25.179 --> 00:34:27.239 does Iguanodon matter more than just being a 00:34:27.239 --> 00:34:29.780 cool skeleton in a museum? I think Iguanodon 00:34:29.780 --> 00:34:32.139 teaches us humility. It teaches us that science 00:34:32.139 --> 00:34:34.639 is not a destination. It's a process. It's a 00:34:34.639 --> 00:34:37.179 verb, not a noun. We're never done. We never 00:34:37.179 --> 00:34:39.619 have the final answer. We're never done. Gideon 00:34:39.619 --> 00:34:41.760 Mantell wasn't stupid for putting the horn on 00:34:41.760 --> 00:34:44.320 the nose. He was using the best comparative anatomy 00:34:44.320 --> 00:34:46.989 he had available to him. Richard Owen wasn't 00:34:46.989 --> 00:34:49.469 stupid for making them elephants. He was correctly 00:34:49.469 --> 00:34:53.030 interpreting the immense mass of the bones. Louis 00:34:53.030 --> 00:34:55.110 Dallow wasn't stupid for creating the kangaroo 00:34:55.110 --> 00:34:58.110 pose. He was reacting to the limb ratios. They 00:34:58.110 --> 00:35:00.170 were all right, based on the evidence they had, 00:35:00.309 --> 00:35:03.429 until they were wrong. Exactly. And today, with 00:35:03.429 --> 00:35:06.309 our all -terrain vehicle, Swiss Army Hand Iguanodon, 00:35:06.409 --> 00:35:09.130 we feel very confident. We think we've got it 00:35:09.130 --> 00:35:12.289 figured out. But are we right? Maybe. Or maybe 00:35:12.289 --> 00:35:14.730 in 50 years, a new scanner will reveal they had 00:35:14.730 --> 00:35:17.250 feathers on their back. Or a colorful dewlap. 00:35:17.650 --> 00:35:20.050 Or that the prehensile pinky finger was used 00:35:20.050 --> 00:35:21.909 for something we haven't even guessed. And that's 00:35:21.909 --> 00:35:23.730 the joy of it, the journey of the thumb spike. 00:35:23.809 --> 00:35:26.269 From a nose horn on a concrete elephant to a 00:35:26.269 --> 00:35:28.969 defensive weapon on a dynamic horizontal walker, 00:35:29.010 --> 00:35:31.789 that journey is the perfect metaphor for human 00:35:31.789 --> 00:35:35.590 curiosity. We guess, we test, we fail, and we 00:35:35.590 --> 00:35:38.090 correct. And Iguanodon has been with us for every 00:35:38.090 --> 00:35:41.139 single step of that 200 -year journey. from a 00:35:41.139 --> 00:35:43.400 country doctor on horseback to the secretron 00:35:43.400 --> 00:35:45.860 particle accelerators we use today. And it will 00:35:45.860 --> 00:35:48.199 probably be with us for the next 200 teaching 00:35:48.199 --> 00:35:50.280 us new things. Well, next time you see a picture 00:35:50.280 --> 00:35:52.940 of an iguanodon, don't just see a dinosaur. See 00:35:52.940 --> 00:35:55.920 a history lesson. See a detective story. And 00:35:55.920 --> 00:35:57.960 definitely keep an eye on that thumb. And be 00:35:57.960 --> 00:36:00.300 very glad you aren't a psyched plant in the early 00:36:00.300 --> 00:36:03.920 Cretaceous. Exactly. Thanks for diving deep with 00:36:03.920 --> 00:36:06.139 us today. Keep asking questions. Keep digging. 00:36:06.280 --> 00:36:07.159 Stay curious.