WEBVTT 00:00:00.000 --> 00:00:02.500 Welcome back to the Deep Dive. Today we are, 00:00:02.720 --> 00:00:05.599 we're not just talking about a dinosaur. We are 00:00:05.599 --> 00:00:08.460 talking about, well, I think it's fair to say 00:00:08.460 --> 00:00:10.080 we're talking about the dinosaur. Right. And 00:00:10.080 --> 00:00:12.779 I really don't say that lightly. No, you're absolutely 00:00:12.779 --> 00:00:15.339 right. It really is the, you know, the definitive 00:00:15.339 --> 00:00:17.239 article, isn't it? It holds a special place. 00:00:17.420 --> 00:00:19.399 It really does. I was thinking about this on 00:00:19.399 --> 00:00:22.820 the way in. If you walk into any kindergarten 00:00:22.820 --> 00:00:24.620 classroom, pretty much anywhere in the world, 00:00:24.739 --> 00:00:28.000 and you ask a five -year -old to draw a dinosaur. 00:00:29.039 --> 00:00:30.640 What are they going to draw? They're going to 00:00:30.640 --> 00:00:32.299 draw one of two things. It's either going to 00:00:32.299 --> 00:00:35.219 be a Tyrannosaurus Rex, you know, big teeth, 00:00:35.340 --> 00:00:38.700 tiny little arms. Or this one, the one with the 00:00:38.700 --> 00:00:41.140 three horns and the big shield on its head. Exactly. 00:00:41.439 --> 00:00:44.320 We are talking about Triceratops. And I feel 00:00:44.320 --> 00:00:46.280 like everyone listening right now has a very, 00:00:46.299 --> 00:00:49.460 very specific image in their head. It's probably 00:00:49.460 --> 00:00:51.679 a plastic toy you had when you were growing up. 00:00:51.759 --> 00:00:54.490 Oh, for sure. Maybe it was from a certain. a 00:00:54.490 --> 00:00:57.890 movie franchise set on an island it's that toy 00:00:57.890 --> 00:01:00.329 box version of the animal which is a great starting 00:01:00.329 --> 00:01:02.170 point i mean it's iconic for a reason but the 00:01:02.170 --> 00:01:06.180 reality of this animal is It's just so much stranger, 00:01:06.379 --> 00:01:09.260 so much more dynamic, and frankly, so much more 00:01:09.260 --> 00:01:12.040 terrifying than that static little plastic toy. 00:01:12.180 --> 00:01:14.379 That is exactly the mission today. We are going 00:01:14.379 --> 00:01:16.859 to take that toy box version and, well, we're 00:01:16.859 --> 00:01:18.239 going to upgrade it. We're going to look at the 00:01:18.239 --> 00:01:20.840 sources. And we have a huge stack today from 00:01:20.840 --> 00:01:23.079 the original 19th century descriptions to some 00:01:23.079 --> 00:01:25.760 really cutting edge papers from the last couple 00:01:25.760 --> 00:01:27.640 of years. And we're going to find out that this 00:01:27.640 --> 00:01:31.060 animal was a marvel of social complexity, a biological 00:01:31.060 --> 00:01:35.760 shapeshifter, and maybe. just maybe a little 00:01:35.760 --> 00:01:38.060 bit bristly. And we absolutely have to talk about 00:01:38.060 --> 00:01:40.420 cowboys. We absolutely have to talk about cowboys. 00:01:40.459 --> 00:01:42.879 I tease that and I promise we will get to the 00:01:42.879 --> 00:01:45.319 Wild West. Yeah. But before we get to the lassoes 00:01:45.319 --> 00:01:47.120 and the ranchers, let's just ground ourselves 00:01:47.120 --> 00:01:49.159 in the name. Yeah. Because it's one of the few 00:01:49.159 --> 00:01:51.099 scientific names that the general public actually 00:01:51.099 --> 00:01:54.579 knows and, you know. uses correctly. It is, yeah. 00:01:54.680 --> 00:01:56.879 It's a linguistic masterpiece, really. It's derived 00:01:56.879 --> 00:01:59.120 straight from ancient Greek. You have tri, which 00:01:59.120 --> 00:02:02.459 means three. Right. You have kiras, which means 00:02:02.459 --> 00:02:05.060 horn. Okay. And then you have emphomes, meaning 00:02:05.060 --> 00:02:08.379 face. Triceratops. Literally. Three horned face. 00:02:08.539 --> 00:02:11.740 It's so elegant, so descriptive. It's perfect. 00:02:11.979 --> 00:02:15.139 It doesn't require a degree in Latin to get the 00:02:15.139 --> 00:02:17.360 picture in your head. You hear the name and you 00:02:17.360 --> 00:02:19.919 see the animal. It is perfect branding. But here's 00:02:19.919 --> 00:02:22.400 the so what question to kick us off. Why does 00:02:22.400 --> 00:02:26.069 this specific dinosaur matter so much? I mean, 00:02:26.090 --> 00:02:28.729 aside from being incredibly cool looking on a 00:02:28.729 --> 00:02:31.669 lunchbox. Well, scientifically, it is. It's foundational. 00:02:31.930 --> 00:02:35.349 It's incredibly important. In phylogenetic taxonomy, 00:02:35.449 --> 00:02:38.689 that's the science of how we classify organisms 00:02:38.689 --> 00:02:42.169 based on their evolutionary relationships. Triceratops 00:02:42.169 --> 00:02:44.750 is actually used as a reference point, as a pillar 00:02:44.750 --> 00:02:47.250 to define what a dinosaur is. Wait, really? Say 00:02:47.250 --> 00:02:49.590 more about that. It's the standard unit. Basically, 00:02:49.590 --> 00:02:52.719 yes. The clade or the group that we call dinosauria, 00:02:52.740 --> 00:02:54.819 it's technically defined as all descendants of 00:02:54.819 --> 00:02:56.840 the most recent common ancestor of Triceratops 00:02:56.840 --> 00:02:59.060 and modern birds. That is heavy. So it's not 00:02:59.060 --> 00:03:00.900 just a random participant in the group. It's 00:03:00.900 --> 00:03:02.879 one of the two pillars that holds up the entire 00:03:02.879 --> 00:03:05.800 definition. Precisely. If you aren't related 00:03:05.800 --> 00:03:09.199 to Triceratops or birds in that specific way, 00:03:09.300 --> 00:03:12.159 by that definition, you aren't a dinosaur. So 00:03:12.159 --> 00:03:15.659 in a very real technical sense, Triceratops anchors 00:03:15.659 --> 00:03:18.580 the entire family tree. And beyond that, historically, 00:03:18.879 --> 00:03:21.139 it's significant because of when it lived, right? 00:03:21.219 --> 00:03:23.080 It's right at the very, very end. Exactly right. 00:03:23.180 --> 00:03:25.740 It was one of the very last non -avian dinosaurs 00:03:25.740 --> 00:03:28.360 standing. It lived at the end of the Maastrichtian 00:03:28.360 --> 00:03:32.479 age for about 68 to 66 million years ago. So 00:03:32.479 --> 00:03:35.460 it was there right up until the asteroid hit. 00:03:35.539 --> 00:03:38.120 If you could go back in time and stand on the 00:03:38.120 --> 00:03:40.259 ground on that final day, you know, just before 00:03:40.259 --> 00:03:43.439 the impact and look up at the sky. The animal 00:03:43.439 --> 00:03:45.599 standing next to you in that forest was very, 00:03:45.659 --> 00:03:48.340 very likely a Triceratops. Talk about witnessing 00:03:48.340 --> 00:03:51.120 the end of an era. It's the final boss of the 00:03:51.120 --> 00:03:53.639 Cretaceous. In many ways, yes. It was the culmination 00:03:53.639 --> 00:03:56.460 of 150 million years of dinosaur evolution. Okay, 00:03:56.500 --> 00:03:58.340 so we know what it is. We know why it matters. 00:03:58.620 --> 00:04:00.280 But I want to go back to when we didn't know 00:04:00.280 --> 00:04:03.180 what it was. Because the discovery story of Triceratops 00:04:03.180 --> 00:04:05.659 is, well, it's a comedy of errors. It's almost 00:04:05.659 --> 00:04:07.979 unbelievable. It really is. And it highlights 00:04:07.979 --> 00:04:10.139 something so important about paleontology. Even 00:04:10.139 --> 00:04:13.770 the absolute... best experts, the giants of the 00:04:13.770 --> 00:04:16.290 field, can get it completely wrong if they don't 00:04:16.290 --> 00:04:18.230 have the whole picture. So let's set the scene. 00:04:18.329 --> 00:04:21.550 It's 1887. We are deep in the American West. 00:04:21.829 --> 00:04:25.610 The Bone Wars are raging. Oh, absolutely. This 00:04:25.610 --> 00:04:28.430 is the peak of the rivalry between Ockneal Charles 00:04:28.430 --> 00:04:31.350 Marsh and Edward Drinker Cope. They're sending 00:04:31.350 --> 00:04:33.750 teams out all over the West, trying to one -up 00:04:33.750 --> 00:04:36.790 each other, naming new species as fast as they 00:04:36.790 --> 00:04:39.129 can dig them up. It's a frantic, competitive 00:04:39.129 --> 00:04:42.569 time. And into this scene walks a geologist named 00:04:42.569 --> 00:04:45.189 George Lyman Cannon. He's working near Denver, 00:04:45.329 --> 00:04:47.430 Colorado. Right. And you have to picture Denver 00:04:47.430 --> 00:04:49.990 in 1887. It's not the metropolis it is today. 00:04:50.110 --> 00:04:52.470 This was a rugged country. Yeah. And Cannon is 00:04:52.470 --> 00:04:54.430 out there doing his geology work, and he finds 00:04:54.430 --> 00:04:56.930 a fossil. Not a whole skeleton, I'm guessing. 00:04:57.110 --> 00:04:59.009 No, and that's the entire problem. It's just 00:04:59.009 --> 00:05:01.930 a pair of large brow horns, the ones over the 00:05:01.930 --> 00:05:04.529 eyes, and they're attached to a fragment of the 00:05:04.529 --> 00:05:06.569 skull roof. It's just the very top of the head. 00:05:06.769 --> 00:05:09.310 Okay. So he wraps them up, puts them in a crate. 00:05:09.639 --> 00:05:12.120 And sends them off to the expert. He sends them 00:05:12.120 --> 00:05:16.100 to Othniel Charles Marsh. And we have to contextualize 00:05:16.100 --> 00:05:19.100 Marsh. This man was at Yale. He was one of the 00:05:19.100 --> 00:05:22.319 titans of early American paleontology. He's the 00:05:22.319 --> 00:05:24.720 guy who named Stegosaurus, Apatosaurus, Allosaurus. 00:05:25.500 --> 00:05:27.560 If anyone in the world should know a dinosaur 00:05:27.560 --> 00:05:30.379 when they see one, it's O .C. Marsh. So Marsh 00:05:30.379 --> 00:05:32.860 gets this crate. He opens it up. He sees two 00:05:32.860 --> 00:05:36.259 massive bone horns. What goes through his mind? 00:05:36.360 --> 00:05:38.870 What's his process? Well, he looks at the horns, 00:05:39.050 --> 00:05:41.730 for sure. But more importantly, he looks at the 00:05:41.730 --> 00:05:44.129 notes on the geology. The person who sent it 00:05:44.129 --> 00:05:47.129 noted the rock formation it came from. Marsh, 00:05:47.350 --> 00:05:49.850 based on what he knew at the time, assumes that 00:05:49.850 --> 00:05:52.509 Formotion is from the Pliocene epoch. And for 00:05:52.509 --> 00:05:54.589 those of us who don't have the geologic timescale 00:05:54.589 --> 00:05:57.290 tattooed on our arms, what does Pliocene mean 00:05:57.290 --> 00:05:59.670 in this context? It means relatively recent, 00:05:59.910 --> 00:06:02.230 geologically speaking. We're talking a few million 00:06:02.230 --> 00:06:05.449 years ago. Crucially, this is long, long after 00:06:05.449 --> 00:06:08.019 the dinosaurs went extinct. Ah. So right off 00:06:08.019 --> 00:06:10.040 the bat, he's ruling out dinosaur. He thinks 00:06:10.040 --> 00:06:11.939 he's looking at a mammal. Exactly. He thinks 00:06:11.939 --> 00:06:14.319 these aren't dinosaur fossils at all. He concludes 00:06:14.319 --> 00:06:16.759 they must belong to some kind of giant extinct 00:06:16.759 --> 00:06:20.420 species of bison. Yes. He formally describes 00:06:20.420 --> 00:06:24.300 it and names it bison alticornis, which means 00:06:24.300 --> 00:06:27.860 the high horned bison. That is just fantastic. 00:06:27.920 --> 00:06:31.860 So the very first triceratops fossils ever cataloged 00:06:31.860 --> 00:06:34.740 were put in the books as a type of cow. A very 00:06:34.740 --> 00:06:37.399 large, very strange cow. But, you know, to be 00:06:37.399 --> 00:06:39.420 fair to Marsh, if you just saw those two brow 00:06:39.420 --> 00:06:42.240 horns in isolation, which are made of bone and 00:06:42.240 --> 00:06:44.480 probably looked a bit like the bony cores of 00:06:44.480 --> 00:06:46.839 modern cattle horns, and you were told the rocks 00:06:46.839 --> 00:06:48.959 they came from are only a few million years old, 00:06:49.040 --> 00:06:52.040 a giant bison isn't an absurd conclusion. I guess 00:06:52.040 --> 00:06:53.899 that's convergent evolution where different animals 00:06:53.899 --> 00:06:56.939 evolve similar shapes. Precisely. But the universe 00:06:56.939 --> 00:06:59.379 wasn't done messing with them yet. Because the 00:06:59.379 --> 00:07:01.779 next big find, and this is my absolute favorite 00:07:01.779 --> 00:07:04.740 part of the whole story, involves a literal cowboy. 00:07:05.220 --> 00:07:08.939 This is the story of Edmund B. Wilson in 1888. 00:07:09.300 --> 00:07:11.740 1888. So a year later, we're in Wyoming now, 00:07:11.819 --> 00:07:13.899 and Edmund is a cowboy. He's not a scientist, 00:07:13.980 --> 00:07:16.300 not a geologist. He's presumably out there on 00:07:16.300 --> 00:07:18.180 horseback checking fences or looking for stray 00:07:18.180 --> 00:07:20.600 cattle. And he's riding along a ravine, minding 00:07:20.600 --> 00:07:22.740 his own business, and he sees something. He sees 00:07:22.740 --> 00:07:25.540 a monstrous skull, as it was later described, 00:07:25.779 --> 00:07:28.560 poking out of the side of the ravine. Now, you 00:07:28.560 --> 00:07:30.319 have to try and imagine that. You're on a horse 00:07:30.319 --> 00:07:32.879 miles from civilization. You've probably never 00:07:32.879 --> 00:07:35.319 seen a dinosaur skeleton in a museum because 00:07:35.319 --> 00:07:38.399 they barely existed yet. And a skull the size 00:07:38.399 --> 00:07:41.420 of a small car is staring at you from out of 00:07:41.420 --> 00:07:44.459 the dirt. It must have been, I mean, terrifying 00:07:44.459 --> 00:07:46.819 or at least deeply confusing. What would you 00:07:46.819 --> 00:07:50.579 even think that was? A dragon? Who knows? And 00:07:50.579 --> 00:07:52.800 Edmund, being a practical man of the West, decides 00:07:52.800 --> 00:07:54.879 he wants to retrieve it. Maybe he thinks it's 00:07:54.879 --> 00:07:57.139 worth money. Maybe he just wants the world's 00:07:57.139 --> 00:07:59.939 greatest trophy for the ranch house. But he doesn't 00:07:59.939 --> 00:08:01.980 have a rock hammer. He doesn't have plaster jackets. 00:08:02.339 --> 00:08:05.000 He has a rope. He has a lasso. This is the most 00:08:05.000 --> 00:08:07.259 American scientific method I have ever heard 00:08:07.259 --> 00:08:09.860 of. I'm going to lasso the science out of the 00:08:09.860 --> 00:08:11.860 ground. It really is. The story goes that he 00:08:11.860 --> 00:08:14.019 throws his lasso around one of the horns. He 00:08:14.019 --> 00:08:15.720 ties the other end to the horn of his saddle 00:08:15.720 --> 00:08:18.279 and he spurs his horse. He tries to yank this 00:08:18.279 --> 00:08:21.160 massive fossil out of the cliff face by brute 00:08:21.160 --> 00:08:23.720 force. And I'm guessing physics happens. Physics 00:08:23.720 --> 00:08:26.779 happens. The fossilized horn, which is essentially 00:08:26.779 --> 00:08:29.759 rock, snaps right off. Oh, that hurts my soul. 00:08:33.700 --> 00:08:36.860 And to make it worse, the jolt of the horn breaking 00:08:36.860 --> 00:08:39.659 off causes the rest of the massive skull to tumble 00:08:39.659 --> 00:08:42.330 down into the cleft of the ravine. out of reach 00:08:42.330 --> 00:08:45.350 but wilson he has the horn he takes that broken 00:08:45.350 --> 00:08:48.169 piece rides back to the ranch and shows it to 00:08:48.169 --> 00:08:50.330 his boss and his boss is the connection right 00:08:50.330 --> 00:08:53.289 yes his boss is a rancher and an amateur fossil 00:08:53.289 --> 00:08:56.929 collector named charles arthur guernsey and guernsey 00:08:56.929 --> 00:08:59.629 thankfully knows who to call he shows the horn 00:08:59.629 --> 00:09:02.379 to a man named john bell hatcher And we need 00:09:02.379 --> 00:09:04.639 to put a pin in Hatcher. He's a major character 00:09:04.639 --> 00:09:07.000 in this story. He is the fossil hunter's fossil 00:09:07.000 --> 00:09:09.559 hunter. If Marsh is the academic general back 00:09:09.559 --> 00:09:12.139 at Yale, Hatcher is the guy on the front lines, 00:09:12.220 --> 00:09:14.840 the Indiana Jones of this whole operation. He 00:09:14.840 --> 00:09:17.320 was unbelievably tough and had an incredible 00:09:17.320 --> 00:09:19.940 eye for finding fossils. So Hatcher sees this 00:09:19.940 --> 00:09:22.460 horn. And what does he think? Does he think bison? 00:09:22.559 --> 00:09:26.259 No way. Hatcher sees this horn and he knows immediately 00:09:26.259 --> 00:09:28.399 this isn't a mammal. He knows this is something 00:09:28.399 --> 00:09:31.179 reptilian and something enormous. He gets Guernsey 00:09:31.179 --> 00:09:33.379 to take him out to the ravine. He manages to 00:09:33.379 --> 00:09:35.480 recover the skull. This very skull becomes the 00:09:35.480 --> 00:09:38.820 holotype, the defining specimen, YPM 1820. And 00:09:38.820 --> 00:09:41.659 he sends it to Marsh back at Yale. Okay. So now 00:09:41.659 --> 00:09:45.700 Marsh has a complete monstrous skull. with a 00:09:45.700 --> 00:09:48.919 beak, with giant brow horns. Surely now, he says, 00:09:49.059 --> 00:09:51.379 okay, definitely not a bison. Well, partially. 00:09:51.600 --> 00:09:54.820 He immediately realizes it's a reptile. He recognizes 00:09:54.820 --> 00:09:57.639 it as belonging to a group he had named earlier 00:09:57.639 --> 00:10:00.440 based on fragments, Ceratops. So he initially 00:10:00.440 --> 00:10:03.179 calls it Ceratops horridus. But then, as his 00:10:03.179 --> 00:10:05.399 team is cleaning the skull up, they find something 00:10:05.399 --> 00:10:08.019 Marsh hadn't seen before, a third horn. The nose 00:10:08.019 --> 00:10:11.529 horn. The nose horn in Triceratops. Oh, so that's 00:10:11.529 --> 00:10:13.309 the final piece of the puzzle. Exactly. That 00:10:13.309 --> 00:10:15.370 third horn on the nose convinces Marsh this is 00:10:15.370 --> 00:10:17.850 a whole new genus distinct from Ceratops. He 00:10:17.850 --> 00:10:20.830 renames it Triceratops' three -horned face. And 00:10:20.830 --> 00:10:23.149 remarkably, to his credit, he publishes a correction. 00:10:23.269 --> 00:10:25.549 He goes back and says, you know that giant bison, 00:10:25.549 --> 00:10:27.409 Bisoneltichornis? That was actually one of these. 00:10:27.490 --> 00:10:30.049 My mistake. That's good science. You have to 00:10:30.049 --> 00:10:32.190 be willing to say, I was wrong. But once they 00:10:32.190 --> 00:10:34.529 knew what to look for, the floodgates opened, 00:10:34.649 --> 00:10:36.889 didn't they? This is where Hatcher really shines. 00:10:37.500 --> 00:10:40.120 It was an absolute avalanche of fossils. Between 00:10:40.120 --> 00:10:44.279 1889 and 1891, just the three -year period, John 00:10:44.279 --> 00:10:46.700 Bell Hatcher went on an absolute tear in Wyoming. 00:10:46.960 --> 00:10:50.960 He collected 31 more or less complete skulls. 00:10:50.980 --> 00:10:54.899 31 skulls in three years. That is an insane level 00:10:54.899 --> 00:10:57.440 of productivity. It's staggering physical labor. 00:10:57.559 --> 00:10:59.320 You have to understand, these aren't chicken 00:10:59.320 --> 00:11:02.019 bones. A triceratops skull with the surrounding 00:11:02.019 --> 00:11:05.360 rock matrix can weigh thousands of pounds. Hatcher 00:11:05.360 --> 00:11:07.500 and his team were digging these out. with pickaxes 00:11:07.500 --> 00:11:10.039 and shovels, wrapping them in burlap and plaster, 00:11:10.320 --> 00:11:12.659 loading them onto horse -drawn wagons, and dragging 00:11:12.659 --> 00:11:15.039 them for miles across the Badlands to the nearest 00:11:15.039 --> 00:11:17.379 railhead. And I've read that Hatcher basically 00:11:17.379 --> 00:11:19.600 destroyed his health doing this work, right? 00:11:19.620 --> 00:11:22.539 The physical toll was immense. He did. He worked 00:11:22.539 --> 00:11:24.700 himself to the bone, often in brutal conditions. 00:11:24.940 --> 00:11:27.120 But because he sent back this incredible wealth 00:11:27.120 --> 00:11:29.940 of material, this library of skulls, March started 00:11:29.940 --> 00:11:31.779 noticing differences between them. Differences 00:11:31.779 --> 00:11:34.259 like what? Well, you know, no two skulls were 00:11:34.259 --> 00:11:37.000 exactly alike. Some had slightly longer brow 00:11:37.000 --> 00:11:40.159 horns that curved upwards more. Some had taller, 00:11:40.259 --> 00:11:43.500 more fan -shaped frills. Some had a big, robust 00:11:43.500 --> 00:11:46.500 nose horn. Some had virtually no nose horn at 00:11:46.500 --> 00:11:48.360 all, just a little bump. And because this was 00:11:48.360 --> 00:11:51.320 the 1800s, and the race was on to name as many 00:11:51.320 --> 00:11:54.149 new species as possible. Marsh went naming crazy. 00:11:54.350 --> 00:11:56.570 He was a classic splitter. If it looks slightly 00:11:56.570 --> 00:11:59.110 different, he gave it a new species name. He 00:11:59.110 --> 00:12:02.250 named Triceratops alatus, Triceratops flabilatus, 00:12:02.450 --> 00:12:04.950 Triceratops calicornis, Triceratops serratus. 00:12:04.950 --> 00:12:06.850 I think he named something like eight or nine 00:12:06.850 --> 00:12:09.190 species in just a couple of years. And this really 00:12:09.190 --> 00:12:11.769 sets the stage for a debate that, honestly, we 00:12:11.769 --> 00:12:13.750 are still having today over a century later. 00:12:14.329 --> 00:12:16.789 Are these all different species living side by 00:12:16.789 --> 00:12:19.570 side? Or is it just one animal that changes shape 00:12:19.570 --> 00:12:22.309 as it grows and ages? That is the central question 00:12:22.309 --> 00:12:24.710 of triceratops science. But before we can even 00:12:24.710 --> 00:12:26.529 get to the shape -shifting, we need to understand 00:12:26.529 --> 00:12:29.169 the baseline. We need to build the beast. If 00:12:29.169 --> 00:12:32.110 you are standing next to a fully grown triceratops 00:12:32.110 --> 00:12:34.590 hortus, what are you looking at? You are looking 00:12:34.590 --> 00:12:38.340 at a biological tank. A meat mountain. laughs 00:12:38.340 --> 00:12:40.500 that that's an accurate description. The sources 00:12:40.500 --> 00:12:43.259 consistently put them at 8 to 9 meters long. 00:12:43.340 --> 00:12:46.460 That's 26 to 30 feet. And weighing anywhere from 00:12:46.460 --> 00:12:49.480 6 to 10 metric tons, some estimates go even higher, 00:12:49.639 --> 00:12:52.059 up to 12. To put that in perspective for everyone, 00:12:52.200 --> 00:12:54.860 that's the size and weight of a very large African 00:12:54.860 --> 00:12:57.500 bull elephant. But it's lower to the ground, 00:12:57.679 --> 00:13:00.519 much bulkier, more powerfully built. And a huge 00:13:00.519 --> 00:13:02.759 chunk of that size, a disproportionate amount, 00:13:02.860 --> 00:13:06.259 is just the head. It has one of the largest skulls 00:13:06.259 --> 00:13:09.059 of any land animal in history. The skull alone 00:13:09.059 --> 00:13:12.059 can be 2 .5 meters long. That's over eight feet. 00:13:12.159 --> 00:13:14.519 Eight feet for just the head. Just the head. 00:13:14.580 --> 00:13:16.399 So think about a standard doorway in your house. 00:13:16.539 --> 00:13:18.799 The entire skull wouldn't fit through it lengthwise. 00:13:18.840 --> 00:13:21.580 It's longer than your doorway is tall. I can't 00:13:21.580 --> 00:13:23.740 even process that. The head is almost a third 00:13:23.740 --> 00:13:26.080 of the entire animal's length. How does that 00:13:26.080 --> 00:13:27.700 not just tip over? How do you even lift that? 00:13:28.200 --> 00:13:30.879 Massive, massive neck muscles and a very specific 00:13:30.879 --> 00:13:33.809 skeletal structure to support it. The first few 00:13:33.809 --> 00:13:36.090 vertebrae of the neck, the cervical vertebrae, 00:13:36.090 --> 00:13:38.789 are actually fused together into a solid block 00:13:38.789 --> 00:13:41.870 of bone called a syncervical. Ah, like a handle. 00:13:42.149 --> 00:13:45.769 Exactly. It creates a rigid, powerful attachment 00:13:45.769 --> 00:13:49.090 point for the enormous ligaments and muscles 00:13:49.090 --> 00:13:51.779 needed to swing that head around. But let's look 00:13:51.779 --> 00:13:54.019 at the business end of that skull, the mouth. 00:13:54.259 --> 00:13:56.639 It's got that beak. It looked like a giant parrot 00:13:56.639 --> 00:13:59.480 beak, but on a rhino. Yes, the rostral bone at 00:13:59.480 --> 00:14:02.080 the front. It's narrow and very deep, which means 00:14:02.080 --> 00:14:04.960 it was incredibly strong. This wasn't for delicate 00:14:04.960 --> 00:14:07.679 nibbling. This was for grasping and plucking 00:14:07.679 --> 00:14:11.149 huge bunches of vegetation. It would have been 00:14:11.149 --> 00:14:13.610 covered in a sharp keratin sheath, and it could 00:14:13.610 --> 00:14:16.470 probably snap through cycad trunks or thick branches 00:14:16.470 --> 00:14:18.970 with ease. But inside the mouth, behind the beak, 00:14:19.029 --> 00:14:20.990 it gets even weirder. They didn't have molars 00:14:20.990 --> 00:14:23.309 for grinding like a cow, right? Not at all. They 00:14:23.309 --> 00:14:24.950 had something far more complex and efficient. 00:14:25.049 --> 00:14:28.129 We call them dental batteries. This is just fascinating 00:14:28.129 --> 00:14:30.210 biological engineering. Okay, break that down 00:14:30.210 --> 00:14:32.389 for me. What is a dental battery? Imagine on 00:14:32.389 --> 00:14:35.789 each side of the jaw you have 36 to 40 columns 00:14:35.789 --> 00:14:38.169 of teeth, all packed tightly together to form 00:14:38.169 --> 00:14:40.429 one continuous cutting surface. Okay, a wall 00:14:40.429 --> 00:14:42.690 of teeth. A wall of teeth. But in each of those 00:14:42.690 --> 00:14:44.929 columns, there were three to five teeth stacked 00:14:44.929 --> 00:14:47.649 vertically, one on top of the other inside the 00:14:47.649 --> 00:14:51.090 jawbone. Stacked, like PEZ dispensers for teeth. 00:14:51.330 --> 00:14:54.129 That is the perfect analogy. As the top tooth, 00:14:54.289 --> 00:14:56.350 the one in use, wore down from chewing tough 00:14:56.350 --> 00:14:58.590 plants, it would fall out and the next one in 00:14:58.590 --> 00:15:00.029 the column would have already moved up to replace 00:15:00.029 --> 00:15:03.570 it. It was a constant conveyor belt of new sharp 00:15:03.570 --> 00:15:05.590 teeth. So how many teeth are we talking about 00:15:05.590 --> 00:15:07.870 in total? At any given time, you could be looking 00:15:07.870 --> 00:15:11.809 at a total of 432 to 800 teeth packed into that 00:15:11.809 --> 00:15:14.629 mouth. That is a lot of teeth for an herbivore. 00:15:14.669 --> 00:15:17.649 A huge number. And the way they worked was unique. 00:15:17.909 --> 00:15:20.330 If you watch a cow chew, they grind their food 00:15:20.330 --> 00:15:23.009 side to side. Triceratops didn't do that. Their 00:15:23.009 --> 00:15:25.289 jaw mechanics meant that the teeth slid past 00:15:25.289 --> 00:15:27.490 each other vertically in a high angle shear. 00:15:27.690 --> 00:15:29.490 So they weren't grinding the plants to a pulp. 00:15:29.570 --> 00:15:31.649 They were slicing and dicing them. Exactly. Like 00:15:31.649 --> 00:15:34.289 a set of self -sharpening scissors or biological 00:15:34.289 --> 00:15:37.830 garden shears. They were processing huge volumes 00:15:37.830 --> 00:15:41.070 of fibrous plant material, palms, cycads, tough 00:15:41.070 --> 00:15:43.710 ferns. These are not easy plants to eat. They 00:15:43.710 --> 00:15:45.899 were like living wood shippers. Okay, moving 00:15:45.899 --> 00:15:48.320 back from that incredible head, we have this 00:15:48.320 --> 00:15:52.039 massive, robust body. And there was a huge debate 00:15:52.039 --> 00:15:54.860 for a very long time about how they actually 00:15:54.860 --> 00:15:58.000 stood, how they held up all that weight. The 00:15:58.000 --> 00:16:00.360 four -limb debate. Yes, this is a classic in 00:16:00.360 --> 00:16:02.639 paleontology. If you look at the old paintings, 00:16:02.820 --> 00:16:05.120 the famous murals by Charles R. Knight from the 00:16:05.120 --> 00:16:08.279 early 1900s, Triceratops is shown with its front 00:16:08.279 --> 00:16:11.419 legs sprawled out wide to the sides, almost like 00:16:11.419 --> 00:16:13.480 a lizard or a crocodile. Like it's in the middle 00:16:13.480 --> 00:16:15.730 of a push -up, permanently. Right. And the logic 00:16:15.730 --> 00:16:19.009 at the time was that the head was so absurdly 00:16:19.009 --> 00:16:22.470 heavy, they needed that wide, stable base of 00:16:22.470 --> 00:16:24.710 support to keep from toppling over. There's always 00:16:24.710 --> 00:16:27.710 a but. But the biomechanics, the skeletal reconstruction, 00:16:27.809 --> 00:16:30.409 and most importantly, the trackways, the fossilized 00:16:30.409 --> 00:16:32.509 footprints they left behind, they all tell a 00:16:32.509 --> 00:16:35.190 different story. The current consensus is that 00:16:35.190 --> 00:16:37.269 they had an intermediate stance. What does that 00:16:37.269 --> 00:16:39.470 mean, intermediate? It means the hind legs were 00:16:39.470 --> 00:16:41.990 fully upright, columnar, right under the hips 00:16:41.990 --> 00:16:44.360 like an elephant's. The front limbs were also 00:16:44.360 --> 00:16:46.940 mostly upright, but the elbows were slightly 00:16:46.940 --> 00:16:50.539 bowed out to the sides. It's not a full sprawl, 00:16:50.539 --> 00:16:52.379 but it's not a perfectly straight pillar either. 00:16:52.620 --> 00:16:55.000 So more like a modern rhinoceros than a lizard. 00:16:55.220 --> 00:16:57.860 Much, much more like a rhino. They were active, 00:16:58.039 --> 00:17:00.980 capable walkers. They weren't just lumbering, 00:17:00.980 --> 00:17:03.980 sprawling beasts. But their hands were weird. 00:17:04.079 --> 00:17:06.799 They retained a primitive condition. Primitive 00:17:06.799 --> 00:17:08.839 how? Well, if you look at your own hand, you 00:17:08.839 --> 00:17:11.279 can rotate your forearm so your palm faces down. 00:17:11.579 --> 00:17:14.630 That's called pronation. Most quadrupeds do this. 00:17:15.190 --> 00:17:16.950 Triceratops couldn't, or at least not fully. 00:17:17.210 --> 00:17:19.950 Its hands were semi -supinated, so its fingers 00:17:19.950 --> 00:17:22.589 pointed out away from the body. So as walking 00:17:22.589 --> 00:17:24.490 with its hands turned out permanently, that seems 00:17:24.490 --> 00:17:26.970 awkward. It does to us, but it clearly worked 00:17:26.970 --> 00:17:29.390 for them. And it gets weirder. It only walked 00:17:29.390 --> 00:17:31.730 on the first three fingers of each hand. Those 00:17:31.730 --> 00:17:35.789 had hoof -like claws. Digits four and five, your 00:17:35.789 --> 00:17:38.289 ring and pinky fingers, were vestigial. They 00:17:38.289 --> 00:17:39.670 were just little nubs that didn't even touch 00:17:39.670 --> 00:17:41.789 the ground and had no claws. It's amazing the 00:17:41.789 --> 00:17:44.089 level of detail we can get from just the bones. 00:17:44.750 --> 00:17:47.309 But recently, we've been getting incredible details 00:17:47.309 --> 00:17:49.529 about the stuff that covered the bones. Let's 00:17:49.529 --> 00:17:51.529 talk about skin. This is really exciting stuff. 00:17:51.630 --> 00:17:54.190 For a hundred years, we just assumed leathery, 00:17:54.190 --> 00:17:57.130 elephant -like skin. It was a default guess. 00:17:57.470 --> 00:18:00.630 But in 2002, a specimen was found in Wyoming, 00:18:00.849 --> 00:18:03.940 nicknamed the Lane specimen. And this one is 00:18:03.940 --> 00:18:06.299 special. It has skin impressions. It does. It's 00:18:06.299 --> 00:18:08.980 preserved via a very rare process called clay 00:18:08.980 --> 00:18:11.720 templating. Basically, after the animal died, 00:18:11.900 --> 00:18:14.440 bacteria formed a slimy mat over the dead body. 00:18:14.980 --> 00:18:17.559 Clay then settled on top of that mat, creating 00:18:17.559 --> 00:18:20.119 a perfect, high -fidelity mold of the skin texture 00:18:20.119 --> 00:18:22.180 before everything rotted away. So what does it 00:18:22.180 --> 00:18:25.269 look like? Is it just scaly? It has large hexagonal 00:18:25.269 --> 00:18:27.309 scales, of course. That's the base texture. But 00:18:27.309 --> 00:18:29.549 in the center of some of the larger scales, particularly 00:18:29.549 --> 00:18:32.230 on the back and tail, there are these conical 00:18:32.230 --> 00:18:34.890 projections, like little nipples or bumps rising 00:18:34.890 --> 00:18:36.769 up out of the middle of the scale. And what does 00:18:36.769 --> 00:18:38.910 that imply? Why is that significant? Well, in 00:18:38.910 --> 00:18:41.630 modern animals, and especially in other dinosaurs 00:18:41.630 --> 00:18:45.170 like Psittacosaurus, which is a very early distant 00:18:45.170 --> 00:18:49.009 cousin of Triceratops, structures exactly like 00:18:49.009 --> 00:18:51.369 that are known to be anchor points for quills 00:18:51.369 --> 00:18:56.299 or bristles. So. A fluffy triceratops. A porcupine 00:18:56.299 --> 00:18:58.599 dino? Maybe not fluffy like a kitten. Think more 00:18:58.599 --> 00:19:01.420 like the sparse, thick bristles on a wild boar 00:19:01.420 --> 00:19:04.960 or the quills on a porcupine. It completely challenges 00:19:04.960 --> 00:19:08.339 that classic image of a purely scaly reptilian 00:19:08.339 --> 00:19:10.640 tank. It might have been a spiky, bristly tank. 00:19:10.740 --> 00:19:12.640 Which honestly somehow makes it even scarier. 00:19:12.779 --> 00:19:14.779 It has a whole new texture to the animal that 00:19:14.779 --> 00:19:16.859 we missed for over a century. It's a fantastic 00:19:16.859 --> 00:19:19.460 reminder that there's always more to learn. Okay, 00:19:19.559 --> 00:19:21.829 let's get to the main event. The part everyone 00:19:21.829 --> 00:19:24.349 knows. The headgear. The three horns and the 00:19:24.349 --> 00:19:27.450 giant frill. Why? What is the point? Why invest 00:19:27.450 --> 00:19:30.529 so much biological energy in growing these massive 00:19:30.529 --> 00:19:32.769 heavy bone structures? This is the million -dollar 00:19:32.769 --> 00:19:34.869 question, and there isn't one simple answer. 00:19:35.009 --> 00:19:36.970 We have three main theories that all probably 00:19:36.970 --> 00:19:39.170 play a part. Let's start with Theory A, the one 00:19:39.170 --> 00:19:41.569 we all learned as kids. Defense against predators. 00:19:41.890 --> 00:19:44.940 The weapons theory. They evolved these horns 00:19:44.940 --> 00:19:47.559 to fight off hungry predators like Tyrannosaurus 00:19:47.559 --> 00:19:51.299 rex. And unlike some childhood myths, this one 00:19:51.299 --> 00:19:54.180 actually holds a lot of water. We have hard, 00:19:54.279 --> 00:19:57.279 direct evidence for this. The smoking gun. Or 00:19:57.279 --> 00:19:59.359 the smoking tooth mark, I guess. There is a famous 00:19:59.359 --> 00:20:02.079 Triceratops specimen that has a partially healed 00:20:02.079 --> 00:20:04.759 bite mark on its brow horn. The spacing of the 00:20:04.759 --> 00:20:07.400 punctures, the shape of the marks, they match 00:20:07.400 --> 00:20:10.339 Tyrannosaurus teeth perfectly. So a T -Rex literally 00:20:10.339 --> 00:20:12.930 bit this thing on the horn. bit it, and broke 00:20:12.930 --> 00:20:15.329 it. But here is the crucial part of that story. 00:20:15.809 --> 00:20:18.970 The bone shows signs of healing. There's callous 00:20:18.970 --> 00:20:21.880 formation around the break. Which means the Triceratops 00:20:21.880 --> 00:20:24.759 survived the encounter. Exactly. It fought a 00:20:24.759 --> 00:20:27.180 T -Rex, took a bite to the face, and lived to 00:20:27.180 --> 00:20:30.019 tell the tale. We also see healed puncture wounds 00:20:30.019 --> 00:20:32.420 on the squamosal bone, that's the side part of 00:20:32.420 --> 00:20:35.119 the frill, that also match predator bites. So 00:20:35.119 --> 00:20:37.160 yes, they absolutely used these horns to defend 00:20:37.160 --> 00:20:39.000 themselves, and they were effective. That is 00:20:39.000 --> 00:20:41.240 just so satisfying to know. The epic battle of 00:20:41.240 --> 00:20:43.119 the giants was a real thing. But what about Theory 00:20:43.119 --> 00:20:45.759 B, the Civil War? Did they use these weapons 00:20:45.759 --> 00:20:48.900 on each other? Intraspecific combat. Fighting 00:20:48.900 --> 00:20:51.160 for mates, fighting for territory. For a long 00:20:51.160 --> 00:20:53.299 time, this was just speculation. It made sense. 00:20:53.380 --> 00:20:55.420 You know, modern horn animals do it. But then 00:20:55.420 --> 00:20:58.259 came the specimen known as Big John. Big John. 00:20:58.619 --> 00:21:00.819 Sounds like a wrestler. Might as well have been. 00:21:01.119 --> 00:21:04.660 Big John is a massive Triceratops specimen, one 00:21:04.660 --> 00:21:07.000 of the largest ever found. And he has a very 00:21:07.000 --> 00:21:11.200 distinct keyhole -shaped hole in his frill. It's 00:21:11.200 --> 00:21:14.039 a traumatic puncture wound. And when you analyze 00:21:14.039 --> 00:21:16.680 the shape and size of that hole, it is a perfect 00:21:16.680 --> 00:21:19.380 match for the tip of another Triceratops' brow 00:21:19.380 --> 00:21:22.170 horn. So he got stabbed in the head by another 00:21:22.170 --> 00:21:24.890 Triceratops. He did. And again, just like the 00:21:24.890 --> 00:21:27.549 T -Rex bite, the bone around the hole shows signs 00:21:27.549 --> 00:21:30.130 of healing. So this wasn't necessarily a fight 00:21:30.130 --> 00:21:32.289 to the death, but it was violent. They were locking 00:21:32.289 --> 00:21:34.970 horns and wrestling, and sometimes they missed 00:21:34.970 --> 00:21:37.009 and stabbed each other in the face shield. Is 00:21:37.009 --> 00:21:39.220 that a one -off, or is it common? It seems to 00:21:39.220 --> 00:21:41.400 be pretty common. There was a statistical analysis 00:21:41.400 --> 00:21:43.819 done that looked at a large sample of skulls. 00:21:43.819 --> 00:21:47.180 They found that about 14 % of Triceratops skulls 00:21:47.180 --> 00:21:48.980 have these kinds of traumatic injuries on the 00:21:48.980 --> 00:21:53.289 frill and face. 14%. 1 in 7. That's a high injury 00:21:53.289 --> 00:21:55.509 rate. That suggests this was a regular part of 00:21:55.509 --> 00:21:57.650 their lives. It does. And what's really interesting 00:21:57.650 --> 00:21:59.809 is when they did the same analysis on Centrosaurus, 00:21:59.970 --> 00:22:02.130 another type of horned dinosaur with different 00:22:02.130 --> 00:22:04.549 horn arrangements, they didn't find those kinds 00:22:04.549 --> 00:22:08.049 of cranial injuries, which suggests Centrosaurus 00:22:08.049 --> 00:22:10.789 may be fought by flank butting or body blows, 00:22:11.109 --> 00:22:14.089 while Triceratops was specifically engaging in 00:22:14.089 --> 00:22:16.970 head -to -head combat, locking horns. Like modern 00:22:16.970 --> 00:22:19.910 deer or antelope do today. Exactly. But then 00:22:19.910 --> 00:22:22.869 that brings us to Theory C. The display theory. 00:22:23.130 --> 00:22:25.789 Maybe it's not all about violence. This is the 00:22:25.789 --> 00:22:28.930 idea that the frill is basically a giant billboard. 00:22:29.029 --> 00:22:31.569 Right. Think about that frill. It's a massive 00:22:31.569 --> 00:22:34.769 surface area of bone. We know from grooves on 00:22:34.769 --> 00:22:36.549 the surface that it was covered in a network 00:22:36.549 --> 00:22:38.390 of blood vessels. So it could have been flush 00:22:38.390 --> 00:22:40.099 with blood. It could have been flushed with the 00:22:40.099 --> 00:22:43.000 blood to produce vibrant colors. Red, blue, complex 00:22:43.000 --> 00:22:45.460 patterns. It was very likely used for sexual 00:22:45.460 --> 00:22:47.839 selection males, showing off their big, colorful 00:22:47.839 --> 00:22:51.220 frills to attract mates, or for species identification. 00:22:51.440 --> 00:22:53.619 A way to say, hey, I'm a triceratops, you're 00:22:53.619 --> 00:22:55.940 a triceratops, let's hang out. But there's a 00:22:55.940 --> 00:22:58.319 complication with the sex appeal only theory, 00:22:58.480 --> 00:23:02.119 right? And it has to do with the babies. A very 00:23:02.119 --> 00:23:05.420 good catch. Yes. Studies of juvenile skulls, 00:23:05.420 --> 00:23:07.880 some of them very small, show that the frill 00:23:07.880 --> 00:23:10.420 and horns start developing very early in life, 00:23:10.619 --> 00:23:13.920 long before the animal is sexually mature. If 00:23:13.920 --> 00:23:15.900 the frill was only for attracting a mate, you 00:23:15.900 --> 00:23:19.039 wouldn't expect a toddler triceratops to be investing 00:23:19.039 --> 00:23:21.640 all that energy into growing one yet. So it's 00:23:21.640 --> 00:23:23.920 probably a mix of all three. It's not one or 00:23:23.920 --> 00:23:26.019 the other. Almost certainly. Evolution is thrifty. 00:23:26.410 --> 00:23:28.690 If you have a giant, metabolically expensive 00:23:28.690 --> 00:23:31.250 structure on your head, you're going to use it 00:23:31.250 --> 00:23:33.970 for everything you possibly can. Species recognition, 00:23:34.490 --> 00:23:37.130 defense against predators, wrestling with rivals, 00:23:37.250 --> 00:23:40.230 showing off to mates, and maybe even thermoregulation 00:23:40.230 --> 00:23:42.829 pumping blood into it to cool down on a hot day. 00:23:43.009 --> 00:23:45.509 A Swiss Army knife of a face. A Swiss Army face. 00:23:45.670 --> 00:23:47.369 I like that. Okay, speaking of faces changing 00:23:47.369 --> 00:23:49.549 over time, we need to talk about the shape -shifting. 00:23:50.130 --> 00:23:51.930 Because this is the part of the deep dive where 00:23:51.930 --> 00:23:54.450 the science gets really, really trippy and controversial. 00:23:55.019 --> 00:23:57.900 This is where we enter the modern era of triceratops 00:23:57.900 --> 00:24:00.180 research, largely driven by the work of Jack 00:24:00.180 --> 00:24:02.819 Horner, Mark Goodwin, and John Scanella. And 00:24:02.819 --> 00:24:05.079 it starts with ontogeny. Ontogeny just means 00:24:05.079 --> 00:24:07.720 growth, right? The study of how an animal changes 00:24:07.720 --> 00:24:11.819 from a baby to an adult. Exactly. In 2006, Horner 00:24:11.819 --> 00:24:14.769 and Goodwin published a landmark study. They 00:24:14.769 --> 00:24:17.630 looked at a growth series of triceratops skulls 00:24:17.630 --> 00:24:21.009 from tiny melon -sized baby skulls all the way 00:24:21.009 --> 00:24:23.410 up to the mass of adults. And what they found 00:24:23.410 --> 00:24:25.730 was that the animal undergoes a radical transformation 00:24:25.730 --> 00:24:28.309 as it ages. It's not just getting bigger. The 00:24:28.309 --> 00:24:30.769 whole head is changing shape. Completely. When 00:24:30.769 --> 00:24:32.869 a triceratops is a baby, its little brow horns 00:24:32.869 --> 00:24:35.410 are just short, straight nubs. As it grows into 00:24:35.410 --> 00:24:37.869 a juvenile, the horns actually elongate and curve 00:24:37.869 --> 00:24:40.910 backward over the frill. Backward. But every 00:24:40.910 --> 00:24:44.180 toy, every movie has them pointing forward. That's 00:24:44.180 --> 00:24:47.099 the adult form. As the animal hits adolescence, 00:24:47.220 --> 00:24:50.140 something incredible happens. The horns stop 00:24:50.140 --> 00:24:52.660 growing backward, the base of the horn remodels, 00:24:52.680 --> 00:24:54.599 and they reorient themselves to start growing 00:24:54.599 --> 00:24:56.880 forward and upward. That sounds painful. How 00:24:56.880 --> 00:24:59.140 does that even work? It involves a lot of bone 00:24:59.140 --> 00:25:01.380 resorption and redeposition. It's a very dynamic 00:25:01.380 --> 00:25:03.599 process. And as they become adults, the horns 00:25:03.599 --> 00:25:05.640 eventually hollow out at the base, probably to 00:25:05.640 --> 00:25:07.579 save weight. But the biggest change, the one 00:25:07.579 --> 00:25:10.099 that sparked the big controversy, is what happens 00:25:10.099 --> 00:25:13.029 to the frill. And this leads us... Directly to 00:25:13.029 --> 00:25:15.109 the biggest debate in recent dinosaur science, 00:25:15.430 --> 00:25:18.750 the Taurosaurus debate. The Taurosaurus debate. 00:25:18.890 --> 00:25:21.470 Okay, some context is needed here. Taurosaurus 00:25:21.470 --> 00:25:24.609 was another dinosaur identified way back in 1891 00:25:24.609 --> 00:25:28.170 by Marsh, right alongside Triceratops. It looks 00:25:28.170 --> 00:25:31.109 very, very similar. Three horns, big frill, but 00:25:31.109 --> 00:25:34.210 with two key differences. It has a much longer, 00:25:34.289 --> 00:25:37.569 more elongated, almost rectangular frill, and 00:25:37.569 --> 00:25:40.529 that frill has two large holes in it. Two big 00:25:40.529 --> 00:25:42.789 windows called fenestri. Whereas Triceratops 00:25:42.789 --> 00:25:44.750 is famous for having a relatively short, solid 00:25:44.750 --> 00:25:47.440 frill. No holes. Correct. For over 100 years, 00:25:47.559 --> 00:25:49.599 everyone agreed. Triceratops is one species. 00:25:49.819 --> 00:25:52.299 Taurosaurus is another. They were cousin species, 00:25:52.700 --> 00:25:54.720 maybe living in the same place at the same time, 00:25:54.740 --> 00:25:57.400 but distinct animals. Until 2010. Until John 00:25:57.400 --> 00:25:59.599 Scanella and Jack Horner published a paper with 00:25:59.599 --> 00:26:02.119 a bombshell hypothesis. Taurosaurus does not 00:26:02.119 --> 00:26:04.119 exist. Excuse me. What do you mean it doesn't 00:26:04.119 --> 00:26:07.079 exist? We have the skulls. They argued that Taurosaurus 00:26:07.079 --> 00:26:10.339 is not a separate species. It is simply a very, 00:26:10.380 --> 00:26:13.400 very old, fully mature geriatric growth stage 00:26:13.400 --> 00:26:16.420 of Triceratops. So Triceratops is the teenager 00:26:16.420 --> 00:26:18.660 and the adult, and Corosaurus is the grandpa. 00:26:18.900 --> 00:26:21.440 That is exactly their argument. Their hypothesis 00:26:21.440 --> 00:26:25.420 is based on this idea of metaplastic bone. The 00:26:25.420 --> 00:26:28.359 bone of the frill isn't like cement. It's living 00:26:28.359 --> 00:26:30.880 tissue that can change throughout an animal's 00:26:30.880 --> 00:26:33.980 life. They argue that as a triceratops gets really 00:26:33.980 --> 00:26:37.359 old, past what we'd consider a prime adult, its 00:26:37.359 --> 00:26:40.380 frill keeps lengthening and flaring out. To keep 00:26:40.380 --> 00:26:42.539 it from getting ridiculously heavy, the bone 00:26:42.539 --> 00:26:45.359 thins out in two specific spots, and eventually, 00:26:45.599 --> 00:26:48.259 those spots resorb completely, opening up into 00:26:48.259 --> 00:26:50.559 the holes we see in Torsorus. That is a wild 00:26:50.559 --> 00:26:52.539 theory. What was the evidence they presented? 00:26:52.839 --> 00:26:55.279 Well, their primary line of evidence was demographic. 00:26:55.440 --> 00:26:57.799 They pointed out that we find lots and lots of 00:26:57.799 --> 00:27:00.720 juvenile and sub -adult triceratops, but we have... 00:27:00.779 --> 00:27:03.420 never, ever found a confirmed juvenile Taurosaurus. 00:27:03.619 --> 00:27:06.740 That is suspicious. Very suspicious. It is. If 00:27:06.740 --> 00:27:09.740 Taurosaurus is a real breeding species, where 00:27:09.740 --> 00:27:13.140 are its babies? Where are the teenagers? All 00:27:13.140 --> 00:27:15.940 the Taurosaurus specimens we have are huge, mature 00:27:15.940 --> 00:27:19.079 animals. They also pointed to a few intermediate 00:27:19.079 --> 00:27:21.440 specimens, skulls that look like they are halfway 00:27:21.440 --> 00:27:24.099 between the two forms, with thinning bone where 00:27:24.099 --> 00:27:26.079 the holes would eventually open. So case closed. 00:27:26.339 --> 00:27:28.980 The textbooks need to be rewritten. Taurosaurus 00:27:28.980 --> 00:27:32.430 is dead. Not so fast. This is science. We love 00:27:32.430 --> 00:27:35.329 to argue. Other paleontologists, people like 00:27:35.329 --> 00:27:38.109 Andrew Farke, Nicholas Longrich, Daniel Field, 00:27:38.369 --> 00:27:41.450 they push back hard. What's their counter argument? 00:27:41.609 --> 00:27:43.750 Where are the holes in the theory, so to speak? 00:27:44.109 --> 00:27:46.150 They have several counterarguments. First, they 00:27:46.150 --> 00:27:47.930 argue that some of the known Taurosaurus specimens 00:27:47.930 --> 00:27:50.410 actually look skeletally mature in their bone 00:27:50.410 --> 00:27:52.390 texture, suggesting they weren't fully grown 00:27:52.390 --> 00:27:55.089 yet, which contradicts the geriatric stage idea. 00:27:55.289 --> 00:27:57.630 And conversely, they've found some absolutely 00:27:57.630 --> 00:28:00.410 massive Triceratops skulls that look extremely 00:28:00.410 --> 00:28:03.009 old. The bones are fully fused and rubbed. All 00:28:03.009 --> 00:28:05.089 the signs of old age are there. But they still 00:28:05.089 --> 00:28:08.849 have the classic solid short frill. So if Triceratops 00:28:08.849 --> 00:28:10.450 is supposed to turn into Taurosaurus when it 00:28:10.450 --> 00:28:13.539 gets old, Why are there these really old triceratops 00:28:13.539 --> 00:28:16.019 that haven't turned yet? Exactly. That's a major 00:28:16.019 --> 00:28:18.660 sticking point. And finally, they argue that 00:28:18.660 --> 00:28:20.960 the proposed mechanism, the bone growing, then 00:28:20.960 --> 00:28:24.019 thinning, then opening holes, is an unprecedented 00:28:24.019 --> 00:28:27.579 and incredibly complex transformation that we 00:28:27.579 --> 00:28:30.319 don't see in any other known animal. So where 00:28:30.319 --> 00:28:33.430 do we stand on this today? Is it 50 -50? It's 00:28:33.430 --> 00:28:35.809 still a very active debate. The consensus has 00:28:35.809 --> 00:28:38.569 not fully landed on one side. There was a more 00:28:38.569 --> 00:28:41.549 recent study in 2022 by Mallon and others that 00:28:41.549 --> 00:28:44.089 argued they have found sub -adult Taurosaurus 00:28:44.089 --> 00:28:47.329 specimens, which, if true, would be strong evidence 00:28:47.329 --> 00:28:50.430 that it's a real separate species. But the shapeshifter 00:28:50.430 --> 00:28:52.789 idea, regardless of whether it's right in this 00:28:52.789 --> 00:28:55.170 specific case, has fundamentally changed how 00:28:55.170 --> 00:28:57.849 we look at all dinosaurs. How so? It's forced 00:28:57.849 --> 00:28:59.730 us to accept that we can't just assume a different 00:28:59.730 --> 00:29:01.509 shape means a different animal. It might just 00:29:01.509 --> 00:29:03.569 be a different age. or even a different sex. 00:29:03.869 --> 00:29:05.730 It makes you wonder how many other dinosaurs 00:29:05.730 --> 00:29:08.410 in the museum are just distinct ages of each 00:29:08.410 --> 00:29:10.890 other. Jack Horner has famously estimated that 00:29:10.890 --> 00:29:13.950 up to a third of all named dinosaur species might 00:29:13.950 --> 00:29:16.349 just be growth stages of other known dinosaurs. 00:29:16.690 --> 00:29:20.349 We might be vastly, vastly overestimating dinosaur 00:29:20.349 --> 00:29:22.569 diversity. That blows my mind. The implications 00:29:22.569 --> 00:29:25.009 of that are huge. Okay. Okay, let's step away 00:29:25.009 --> 00:29:26.890 from the bones for a minute and look at the world 00:29:26.890 --> 00:29:30.329 they actually lived in. Part 5, Life in the Late 00:29:30.329 --> 00:29:33.549 Cretaceous. We are in Laramidia. This was an 00:29:33.549 --> 00:29:36.130 island continent. During the late Cretaceous, 00:29:36.130 --> 00:29:38.809 a shallow sea called the Western Interior Seaway 00:29:38.809 --> 00:29:42.329 split North America in two. Laramidia was the 00:29:42.329 --> 00:29:44.990 western strip, what is now Montana, Wyoming, 00:29:45.349 --> 00:29:48.450 the Dakotas, Alberta. And the environment itself, 00:29:48.609 --> 00:29:52.210 what would it look and feel like? Humid. Subtropical. 00:29:52.289 --> 00:29:54.329 You should be thinking of coastal floodplains, 00:29:54.349 --> 00:29:57.410 swampy forests, meandering rivers. Think Louisiana 00:29:57.410 --> 00:29:59.849 or the Florida Everglades, but the trees are 00:29:59.849 --> 00:30:02.750 conifers, ferns, and early palms. And based on 00:30:02.750 --> 00:30:04.869 the fossil record, if you were to take a walk 00:30:04.869 --> 00:30:06.390 through that forest, you would essentially trip 00:30:06.390 --> 00:30:09.029 over a triceratops. They were unbelievably abundant. 00:30:09.490 --> 00:30:12.150 The paleontologist Robert Backer, who is another 00:30:12.150 --> 00:30:14.910 famous and colorful figure in the field, estimated 00:30:14.910 --> 00:30:17.549 that at the very, very end of the Cretaceous, 00:30:17.569 --> 00:30:20.089 in the ecosystems preserved in the Hell Creek 00:30:20.089 --> 00:30:24.140 Formation, Triceratops made up five -sixths of 00:30:24.140 --> 00:30:27.440 the entire large dinosaur fauna. Five -sixths? 00:30:27.460 --> 00:30:30.180 That's more than 80%. It's overwhelmingly dominant. 00:30:30.319 --> 00:30:32.700 It's an ecosystem completely controlled by this 00:30:32.700 --> 00:30:35.700 one mega herbivore. The famous fossil hunter 00:30:35.700 --> 00:30:39.519 Barnum Brown once claimed he saw 500 Triceratops 00:30:39.519 --> 00:30:42.380 skulls in the field in a single season. They 00:30:42.380 --> 00:30:44.920 were the bison or the cows of the Cretaceous, 00:30:44.920 --> 00:30:46.519 at least in terms of their sheer numbers. Were 00:30:46.519 --> 00:30:49.480 they social like cows? Did they live in big herds? 00:30:49.900 --> 00:30:51.680 That's the tricky question. The evidence is ambiguous. 00:30:51.779 --> 00:30:53.819 We usually find their remains in isolation. A 00:30:53.819 --> 00:30:55.880 single skull here, a partial skeleton there. 00:30:56.039 --> 00:30:58.819 We don't have those massive bone beds of thousands 00:30:58.819 --> 00:31:01.160 of Triceratops all dying together like we do 00:31:01.160 --> 00:31:02.960 with some duck -billed dinosaurs. So they were 00:31:02.960 --> 00:31:05.059 probably lungers. That was the traditional view. 00:31:05.140 --> 00:31:09.240 Mostly solitary. But... There are a few tantalizing 00:31:09.240 --> 00:31:12.180 exceptions. There is a fossil site in Montana 00:31:12.180 --> 00:31:14.420 that has the remains of three juveniles preserved 00:31:14.420 --> 00:31:17.319 together, maybe a little youth gang. And another 00:31:17.319 --> 00:31:19.940 site in Wyoming has three individuals of varying 00:31:19.940 --> 00:31:22.900 sizes, a large one, a medium one, and a small 00:31:22.900 --> 00:31:25.240 one found together, perhaps a small family unit. 00:31:25.400 --> 00:31:27.839 And there's that one specific pathology you mentioned 00:31:27.839 --> 00:31:30.700 earlier. Oh, the stepped -on tail. Yes. There's 00:31:30.700 --> 00:31:32.940 a triceratops vertebra from the tail that shows 00:31:32.940 --> 00:31:36.200 a healed crush injury, the best explanation anyone 00:31:36.200 --> 00:31:38.720 has come up with. Another triceratops accidentally 00:31:38.720 --> 00:31:40.880 stepped on its tail. Which implies they were 00:31:40.880 --> 00:31:42.579 walking close enough together to step on each 00:31:42.579 --> 00:31:44.759 other's tails. Exactly. So the current thinking 00:31:44.759 --> 00:31:47.119 is maybe they lived in small family groups or 00:31:47.119 --> 00:31:50.299 had loose associations, but probably not those 00:31:50.299 --> 00:31:53.039 thundering herds of thousands that you see in 00:31:53.039 --> 00:31:55.059 movies. Now, you mentioned the environment was 00:31:55.059 --> 00:31:57.890 warm and subtropical. Let's talk metabolism. 00:31:58.190 --> 00:32:00.769 Yeah. Was Triceratops warm -blooded like a mammal 00:32:00.769 --> 00:32:04.069 or cold -blooded like a lizard? The great metabolism 00:32:04.069 --> 00:32:07.509 debate. This seesaws back and forth constantly 00:32:07.509 --> 00:32:10.630 in paleontology. For a long time, the idea of 00:32:10.630 --> 00:32:13.849 gigantothermy was popular. The idea that they 00:32:13.849 --> 00:32:16.529 were so huge, they just stayed warm by retaining 00:32:16.529 --> 00:32:19.109 heat. Like a giant living pizza stone, it takes 00:32:19.109 --> 00:32:21.759 all day to cool down. A perfect analogy. But 00:32:21.759 --> 00:32:25.380 a very recent study in 2022 by Jasmina Wayman 00:32:25.380 --> 00:32:27.980 and her colleagues looked at the chemical signals 00:32:27.980 --> 00:32:30.980 of metabolism preserved in the fossil bone, and 00:32:30.980 --> 00:32:32.900 their results suggested that Triceratops might 00:32:32.900 --> 00:32:36.180 have been... Ectothermic. Cold -blooded. A 10 00:32:36.180 --> 00:32:38.740 -ton cold -blooded animal. Or at least having 00:32:38.740 --> 00:32:41.359 a much lower metabolic rate, more similar to 00:32:41.359 --> 00:32:44.339 modern reptiles than to birds or mammals, which 00:32:44.339 --> 00:32:46.259 is really weird because all the evidence suggests 00:32:46.259 --> 00:32:48.980 their earlier, smaller ancestors were warm -blooded. 00:32:49.160 --> 00:32:51.400 So they might have evolved back to a slower metabolism. 00:32:51.559 --> 00:32:54.160 That seems counterintuitive. It's possible. If 00:32:54.160 --> 00:32:56.200 you're a giant animal living in a warm, stable 00:32:56.200 --> 00:32:58.579 climate, generating too much of your own internal 00:32:58.579 --> 00:33:00.920 heat can actually be a problem. You risk overheating. 00:33:01.039 --> 00:33:03.519 So maybe for an animal this big, slowing down... 00:33:03.529 --> 00:33:05.349 the internal furnace was actually a selective 00:33:05.349 --> 00:33:07.609 advantage just lounging in the ferns soaking 00:33:07.609 --> 00:33:10.569 up the sun and eating palms eating a lot of palms 00:33:10.569 --> 00:33:13.869 and this leads to a really cool ecological detail 00:33:13.869 --> 00:33:17.970 niche partitioning we know for a fact they lived 00:33:17.970 --> 00:33:21.430 alongside another giant herbivore the duck -billed 00:33:21.430 --> 00:33:24.210 dinosaur edmontosaurus right so you have two 00:33:24.210 --> 00:33:27.450 massive plant eaters in the same forest how did 00:33:27.450 --> 00:33:29.009 they not just eat all the same food and start 00:33:29.009 --> 00:33:31.619 each other out Isotope studies of the enamel 00:33:31.619 --> 00:33:34.000 in their teeth give us the answer. The different 00:33:34.000 --> 00:33:35.960 chemical signatures show they were eating different 00:33:35.960 --> 00:33:38.819 things from the same environment. Triceratops, 00:33:38.859 --> 00:33:41.420 with its powerful beak and shearing teeth, was 00:33:41.420 --> 00:33:43.779 eating tougher, lower -growing vegetation things 00:33:43.779 --> 00:33:47.200 like ferns and cycads. And Montasaurus, with 00:33:47.200 --> 00:33:49.700 its broader beak, was likely browsing on softer 00:33:49.700 --> 00:33:51.819 plants or things that were slightly higher up. 00:33:51.900 --> 00:33:54.339 They split the menu. Nature always finds a way 00:33:54.339 --> 00:33:56.640 to pack more species in. It really does. So let's 00:33:56.640 --> 00:33:58.480 bring this incredible deep dive in for landing. 00:33:58.990 --> 00:34:01.630 We started with a bison mistake. We went through 00:34:01.630 --> 00:34:04.269 the wild story of the cowboy and the lasso. We 00:34:04.269 --> 00:34:06.390 built this biological tank with a parrot's beak 00:34:06.390 --> 00:34:09.409 and garden shears for teeth. We covered the epic 00:34:09.409 --> 00:34:12.190 battles with T -Rex, the brawls with each other, 00:34:12.289 --> 00:34:14.630 and the mind -bending idea of a shape -shifting 00:34:14.630 --> 00:34:18.530 skull. It's an amazing journey. From a few fragmentary 00:34:18.530 --> 00:34:21.789 horns to a complex, living, breathing animal 00:34:21.789 --> 00:34:24.750 that dominated its world. What's the single biggest 00:34:24.750 --> 00:34:26.889 takeaway for you? When you think of Triceratops 00:34:26.889 --> 00:34:29.699 now, what's the image that comes to mind? For 00:34:29.699 --> 00:34:31.519 me, it's resilience. This was one of the last 00:34:31.519 --> 00:34:33.760 ones standing. It evolved to be unbelievably 00:34:33.760 --> 00:34:36.699 robust, to be adaptable. It survived predator 00:34:36.699 --> 00:34:38.679 attacks that would kill almost anything else. 00:34:38.800 --> 00:34:41.139 It survived brutal injuries from its own kind. 00:34:41.380 --> 00:34:44.199 It so thoroughly dominated its landscape that 00:34:44.199 --> 00:34:46.239 it made up the vast majority of all large animals. 00:34:46.579 --> 00:34:49.579 It's the ultimate survivor. Right up until the 00:34:49.579 --> 00:34:52.340 day, survival was no longer an option. And for 00:34:52.340 --> 00:34:55.050 me, it's the mystery that's still left. The Taurosaurus 00:34:55.050 --> 00:34:57.670 question is still unresolved. We're still debating 00:34:57.670 --> 00:34:59.690 about the bristles. We're still piecing together 00:34:59.690 --> 00:35:02.789 its social behavior. Even with hundreds of skulls, 00:35:02.789 --> 00:35:04.829 we are still arguing about the fundamental nature 00:35:04.829 --> 00:35:07.070 of what it actually was. And that's the beauty 00:35:07.070 --> 00:35:09.769 of paleontology, isn't it? The past is never 00:35:09.769 --> 00:35:12.369 a closed book. There's always another fossil, 00:35:12.489 --> 00:35:14.409 another discovery that can change everything. 00:35:14.809 --> 00:35:17.190 Here's my final provocative thought for you, 00:35:17.269 --> 00:35:20.940 the listener, today. We talked early on about 00:35:20.940 --> 00:35:23.420 how Triceratops is used to define the entire 00:35:23.420 --> 00:35:26.880 group Dinosauria. It's one of the two anchors, 00:35:26.920 --> 00:35:29.900 binding the mighty Triceratops to the modern 00:35:29.900 --> 00:35:32.739 songbird. Yes, the two killers of Dinosauria. 00:35:33.119 --> 00:35:35.599 But think about that shapeshifter concept again. 00:35:36.319 --> 00:35:38.760 If Taurosaurus, an animal that looked different 00:35:38.760 --> 00:35:40.760 enough to be named a separate species for 100 00:35:40.760 --> 00:35:44.739 years, is just an old Triceratops, and if Jack 00:35:44.739 --> 00:35:47.019 Horner is even partially right that maybe a third 00:35:47.019 --> 00:35:49.719 of all dinosaur species are just different growth 00:35:49.719 --> 00:35:52.519 stages, I want you to reconsider the next time 00:35:52.519 --> 00:35:55.019 you walk through a museum. Look at the skeletons 00:35:55.019 --> 00:35:57.380 lined up in the hall. How many of those are actually 00:35:57.380 --> 00:35:59.500 unique species, and how many might just be the 00:35:59.500 --> 00:36:01.760 teenager version of the skeleton standing right 00:36:01.760 --> 00:36:03.760 next to the adult version? It makes you look 00:36:03.760 --> 00:36:05.739 at the concept of biodiversity in a whole new 00:36:05.739 --> 00:36:08.179 way. Are we looking at a prehistoric zoo filled 00:36:08.179 --> 00:36:10.760 with hundreds of different species? Or are we 00:36:10.760 --> 00:36:12.860 looking at a combination nursery, high school, 00:36:12.900 --> 00:36:15.119 and retirement home for just a handful of very 00:36:15.119 --> 00:36:17.920 changeable ones? A nursery and a retirement home. 00:36:18.019 --> 00:36:21.260 I love that. On that note, thanks for diving 00:36:21.260 --> 00:36:24.079 deep with us today. Keep asking questions and 00:36:24.079 --> 00:36:26.960 keep looking at the bones. And please don't lasso 00:36:26.960 --> 00:36:29.039 the fossils. Please do not lasso the fossils. 00:36:29.159 --> 00:36:29.840 We'll see you next time.