WEBVTT 00:00:00.000 --> 00:00:02.799 Welcome back to the Deep Dive. Today we're opening 00:00:02.799 --> 00:00:05.080 a cold case file that's been sitting in the archives 00:00:05.080 --> 00:00:08.119 of paleontology for, what, almost 150 years now. 00:00:08.240 --> 00:00:10.179 Just about. We're talking about a creature that 00:00:10.179 --> 00:00:13.160 you know. I guarantee you know it. It's on gas 00:00:13.160 --> 00:00:16.339 station logos, it's the star of arguably the 00:00:16.339 --> 00:00:19.059 most heartbreaking kids movie ever made, and 00:00:19.059 --> 00:00:21.480 it's the centerpiece of every natural history 00:00:21.480 --> 00:00:24.320 museum. And yet, if you really look at the history 00:00:24.320 --> 00:00:27.410 of this animal, it's... Basically a rap sheet 00:00:27.410 --> 00:00:31.649 of mistaken identity, academic, well, vandalism, 00:00:31.649 --> 00:00:34.909 and just a profound biological misunderstanding. 00:00:35.549 --> 00:00:37.750 Exactly. We're talking about the Apatosaurus. 00:00:38.289 --> 00:00:40.210 And if you are sitting there screaming, don't 00:00:40.210 --> 00:00:43.429 you mean Brontosaurus, at your device, hold that 00:00:43.429 --> 00:00:45.950 thought. Because that name is just the tip of 00:00:45.950 --> 00:00:48.070 the iceberg. Today we're going to find out why 00:00:48.070 --> 00:00:50.229 this animal spent 50 years wearing the wrong 00:00:50.229 --> 00:00:52.630 head. We're going to explore why it was called 00:00:52.630 --> 00:00:54.570 a swamp monster when it was really a land tank. 00:00:54.990 --> 00:00:56.590 And we're going to get into some high level data 00:00:56.590 --> 00:00:58.770 that suggests everything we thought we knew about 00:00:58.770 --> 00:01:02.590 how a 20 ton animal breathes might be, well, 00:01:02.689 --> 00:01:05.409 completely wrong. It's a messy story. It involves 00:01:05.409 --> 00:01:08.969 the infamous Bone Wars, some very fragile egos, 00:01:08.969 --> 00:01:11.650 and some really cutting -edge computer modeling 00:01:11.650 --> 00:01:13.890 that has just turned the family tree completely 00:01:13.890 --> 00:01:16.730 upside down. So let's get into it. We are pulling 00:01:16.730 --> 00:01:19.329 from a massive stack of sources today, everything 00:01:19.329 --> 00:01:22.590 from the original 1877 Field Notes by Othniel 00:01:22.590 --> 00:01:27.140 Charles Marsh, all the way to a huge... 2015 00:01:27.140 --> 00:01:30.040 phylogenetic analysis. Right, the one by T -Shop 00:01:30.040 --> 00:01:32.459 and his colleagues, plus some fascinating biomechanics 00:01:32.459 --> 00:01:34.760 papers from as recent as 2020. We're covering 00:01:34.760 --> 00:01:37.159 the whole timeline of discovery. Let's start 00:01:37.159 --> 00:01:40.420 with that name, Apatosaurus. It's Greek for deceptive 00:01:40.420 --> 00:01:44.579 lizard. Now, usually dinosaur names are the marketing 00:01:44.579 --> 00:01:48.459 gold. Tyrannosaurus is the tyrant lizard, Velociraptor. 00:01:48.459 --> 00:01:52.060 So why on earth did Marsh call this magnificent 00:01:52.060 --> 00:01:55.010 giant deceptive? Was it... Like hiding something? 00:01:55.310 --> 00:01:56.909 It's funny people often think that. That the 00:01:56.909 --> 00:01:59.409 name implies it was sneaky or camouflaged or 00:01:59.409 --> 00:02:01.290 that it was tricking the scientists. But the 00:02:01.290 --> 00:02:03.409 deception was purely anatomical. You have to 00:02:03.409 --> 00:02:06.390 remember this is 1877. Marsh is looking at a 00:02:06.390 --> 00:02:08.949 partial skeleton. He's examining the chevron 00:02:08.949 --> 00:02:11.409 bones. These are the small bones on the underside 00:02:11.409 --> 00:02:13.129 of the tail that, you know, protect the blood 00:02:13.129 --> 00:02:15.610 vessels. Right. I'm with you. And in Apatosaurus, 00:02:15.930 --> 00:02:19.030 these chevrons, they didn't look like the dinosaur 00:02:19.030 --> 00:02:22.629 bones Marsh was used to. They looked, well, deceptively 00:02:22.629 --> 00:02:25.150 like the chevrons of a mosasaur. A mosasaur. 00:02:25.189 --> 00:02:26.949 You mean the marine reptiles, the sea monsters 00:02:26.949 --> 00:02:29.650 of the Cretaceous. Exactly those. So Marsh saw 00:02:29.650 --> 00:02:31.289 these tail bones and thought, this is weird. 00:02:31.389 --> 00:02:33.710 It looks like a marine reptile's tail structure 00:02:33.710 --> 00:02:36.810 grafted onto a... land animal, hence Apatosaurus, 00:02:37.250 --> 00:02:40.210 the deceptive lizard. It tricked him. So that's 00:02:40.210 --> 00:02:43.830 1877. Marsh publishes the name. But then only 00:02:43.830 --> 00:02:47.629 two years later, 1879, his team sends him another 00:02:47.629 --> 00:02:50.569 shipment of bones. And this is where the trouble 00:02:50.569 --> 00:02:52.669 really starts. Oh, yeah. This new skeleton was 00:02:52.669 --> 00:02:55.629 spectacular. It was huge. It was relatively complete. 00:02:55.669 --> 00:02:57.750 And Marsh was absolutely floored by it. Now, 00:02:57.770 --> 00:02:59.349 you have to understand the context here. This 00:02:59.349 --> 00:03:01.430 is the height of the bone wars. It's the height 00:03:01.430 --> 00:03:04.879 of the bone wars. Marsh is in this bitter, frantic 00:03:04.879 --> 00:03:07.620 race against his rival, Edward Drinker Cope. 00:03:07.740 --> 00:03:09.860 They're just trying to name as many new species 00:03:09.860 --> 00:03:12.639 as they can to outdo each other. Quantity over 00:03:12.639 --> 00:03:15.120 quality, they say. Often, yes. So Marsh sees 00:03:15.120 --> 00:03:17.960 this massive skeleton, assumes it's a new species, 00:03:18.139 --> 00:03:20.360 and gives it arguably the best name in the history 00:03:20.360 --> 00:03:23.819 of science. Brontosaurus excelsis. Noble thunder 00:03:23.819 --> 00:03:26.669 lizard. It's a great name. It's so evocative. 00:03:26.710 --> 00:03:28.669 It sounds like a creature that shakes the earth 00:03:28.669 --> 00:03:30.770 when it walks. And because that skeleton was 00:03:30.770 --> 00:03:33.469 so complete, it became the first sauropod ever 00:03:33.469 --> 00:03:36.330 mounted in a major museum. The public didn't 00:03:36.330 --> 00:03:38.689 see a patasaurus. They saw a brontosaurus. They 00:03:38.689 --> 00:03:40.849 fell in love with the thunder lizard. But scientifically, 00:03:41.030 --> 00:03:42.949 the clock was ticking on that name from the start. 00:03:43.090 --> 00:03:46.789 It was. In 1903, a paleontologist, Elmer Riggs, 00:03:46.870 --> 00:03:50.340 at the Field Museum in Chicago. He takes a hard 00:03:50.340 --> 00:03:52.919 clinical look at the two specimens. He compares 00:03:52.919 --> 00:03:56.800 the 1877 Apatosaurus and the 1879 Brontosaurus. 00:03:57.280 --> 00:03:58.960 And he figures it out. He figures it out. He 00:03:58.960 --> 00:04:01.180 realizes they're the same animal. The differences 00:04:01.180 --> 00:04:03.680 Marsh had seen were mostly due to ontogeny, which 00:04:03.680 --> 00:04:06.000 is just a fancy word for growth stages. So the 00:04:06.000 --> 00:04:08.219 Apatosaurus was just a teenager. Essentially, 00:04:08.300 --> 00:04:10.759 yes. The Apatosaurus specimen was a juvenile 00:04:10.759 --> 00:04:12.900 and the Brontosaurus was an adult. They were 00:04:12.900 --> 00:04:15.520 the same genus. And in the strict rules of taxonomy, 00:04:15.719 --> 00:04:18.699 there is only one law that matters. Priority. 00:04:19.310 --> 00:04:22.189 First name wins. Apatosaurus was published in 00:04:22.189 --> 00:04:27.110 1877, so it has priority. Brontosaurus 1879 becomes 00:04:27.110 --> 00:04:30.750 a junior synonym. It's technically invalid. In 00:04:30.750 --> 00:04:33.769 1903, the thunder lizard ceased to exist. But 00:04:33.769 --> 00:04:35.490 and this is the part that always confuses me. 00:04:35.589 --> 00:04:38.670 I grew up in the 90s. I ate Bronto burgers. I 00:04:38.670 --> 00:04:41.250 watched the land before time. If Riggs killed 00:04:41.250 --> 00:04:43.870 the name in 1903, why did it survive for another 00:04:43.870 --> 00:04:46.649 century? You can thank Henry Fairfield Osborne 00:04:46.649 --> 00:04:48.610 for that. He was the head of the American Museum 00:04:48.610 --> 00:04:51.269 of Natural History, a titan. the field and frankly 00:04:51.269 --> 00:04:53.509 a bit of a chaotic figure with a massive ego. 00:04:53.689 --> 00:04:55.769 And he just liked the name better. He liked Brontosaurus 00:04:55.769 --> 00:04:58.329 better. He had a label to print for his museum 00:04:58.329 --> 00:05:00.850 and he essentially just ignored Riggs publication. 00:05:01.230 --> 00:05:03.639 He just ignored a peer reviewed correction. He 00:05:03.639 --> 00:05:05.779 did. And when you run the most famous museum 00:05:05.779 --> 00:05:09.100 in the world, your label becomes the truth for 00:05:09.100 --> 00:05:11.939 millions of people. So you had this split reality 00:05:11.939 --> 00:05:14.939 where scientists quietly said Apatosaurus in 00:05:14.939 --> 00:05:17.459 their papers and the entire rest of the world 00:05:17.459 --> 00:05:20.439 said Brontosaurus. That's unbelievable. It's 00:05:20.439 --> 00:05:22.920 like branding just completely won out over fact. 00:05:23.120 --> 00:05:25.360 For about 100 years, yeah. But hold on, the outline 00:05:25.360 --> 00:05:28.899 mentions a plot twist in 2015. So just when we 00:05:28.899 --> 00:05:30.899 finally got everyone to stop saying brontosaurus, 00:05:31.240 --> 00:05:33.199 I feel like I spent years correcting my friends. 00:05:33.379 --> 00:05:36.060 The science flipped again. This is why paleontology 00:05:36.060 --> 00:05:38.279 is so exciting, right? It's never truly settled. 00:05:38.420 --> 00:05:41.139 In 2015, Emmanuel Chopp and his team published 00:05:41.139 --> 00:05:44.069 this massive study. And I mean massive. They 00:05:44.069 --> 00:05:46.129 didn't just look at Apatosaurus. They looked 00:05:46.129 --> 00:05:48.810 at the whole family of Diplodocidae. How many 00:05:48.810 --> 00:05:51.930 data points are we talking? They analyzed 477 00:05:51.930 --> 00:05:54.589 different morphological characters across 81 00:05:54.589 --> 00:05:57.709 individual specimens. Wow. So they're measuring 00:05:57.709 --> 00:06:01.149 every single bump on every bump. Precisely. They 00:06:01.149 --> 00:06:03.990 fed all this data into a computer algorithm to 00:06:03.990 --> 00:06:06.649 sort out the family tree. And the algorithm... 00:06:07.610 --> 00:06:10.569 It spit out a surprise. It clustered the original 00:06:10.569 --> 00:06:13.810 brontosaurus skeleton that 1879 won apart from 00:06:13.810 --> 00:06:15.829 the apatosaurus cluster. Distinct enough to be 00:06:15.829 --> 00:06:18.029 its own genus again. According to their data, 00:06:18.089 --> 00:06:21.189 yes, they identified key differences. For instance, 00:06:21.310 --> 00:06:24.129 in the neck structure, apatosaurus has a much 00:06:24.129 --> 00:06:27.290 wider, more robust neck and also in the shoulder 00:06:27.290 --> 00:06:29.990 blade. They concluded that, yeah, the differences 00:06:29.990 --> 00:06:32.509 were significant enough to separate them. So 00:06:32.509 --> 00:06:34.949 brontosaurus was resurrected. This is a brontosaurus 00:06:34.949 --> 00:06:37.379 is back. For real this time? It's considered 00:06:37.379 --> 00:06:40.040 valid by many paleontologists now. Not all of 00:06:40.040 --> 00:06:42.220 them, mind you. Taxonomy is a consensus game. 00:06:42.420 --> 00:06:44.959 But for now, yes, you can say brontosaurus without 00:06:44.959 --> 00:06:47.439 a scientist correcting you. It's recognized as 00:06:47.439 --> 00:06:49.620 a separate, slightly more slender cousin of the 00:06:49.620 --> 00:06:52.339 tank -like apatosaurus. That is a rollercoaster. 00:06:52.500 --> 00:06:54.959 But the name isn't the only identity crisis this 00:06:54.959 --> 00:06:57.220 poor animal suffered. We have to talk about the 00:06:57.220 --> 00:07:00.230 head. Ah, yes. the Frankenstein portion of the 00:07:00.230 --> 00:07:02.209 story. Because for a long time, the Apatosaurus 00:07:02.209 --> 00:07:05.170 literally had the wrong head screwed onto its 00:07:05.170 --> 00:07:07.829 body. And it all stems from a simple problem 00:07:07.829 --> 00:07:11.129 in taphonomy, the study of how organisms decay. 00:07:11.990 --> 00:07:14.149 Sauropod skulls are pretty small compared to 00:07:14.149 --> 00:07:15.910 their bodies, and the connection to the neck 00:07:15.910 --> 00:07:18.689 is fragile. So when the animal dies, the head 00:07:18.689 --> 00:07:21.620 often detaches. and just rolls away so you find 00:07:21.620 --> 00:07:23.379 the massive body but the head is gone exactly 00:07:23.379 --> 00:07:26.899 marsh's skeletons were headless but museums need 00:07:26.899 --> 00:07:29.019 to display complete animals right you can't put 00:07:29.019 --> 00:07:32.160 a headless giant in the main hall so a guy named 00:07:32.160 --> 00:07:34.800 adam herman at the american museum needed a head 00:07:34.800 --> 00:07:37.500 for his mount and the only sauropod skull they 00:07:37.500 --> 00:07:39.720 really knew well at the time belonged to camerasaurus 00:07:39.720 --> 00:07:42.879 okay paint a picture for us what does a camerasaurus 00:07:42.879 --> 00:07:46.160 head look like Think of a bulldog. It's boxy, 00:07:46.160 --> 00:07:48.980 high -arching nose, a blunt snout, and these 00:07:48.980 --> 00:07:51.939 big spoon -shaped teeth for chomping tough vegetation. 00:07:52.240 --> 00:07:55.240 It's a really heavy, robust skull. And Apatosaurus 00:07:55.240 --> 00:07:57.660 is a heavy, robust animal, so they just assumed. 00:07:58.019 --> 00:08:00.480 They made an assumption. Big body, big blocky 00:08:00.480 --> 00:08:02.860 head. They sculpted a Camasaurus -like skull 00:08:02.860 --> 00:08:05.079 out of plaster and stuck it on the Apatosaurus' 00:08:05.259 --> 00:08:07.019 neck. And that became the image of the dinosaur 00:08:07.019 --> 00:08:09.519 for decades. Every toy, every movie, it was this 00:08:09.519 --> 00:08:11.740 boxy, flat -faced creature. But there were clues 00:08:11.740 --> 00:08:16.480 that this was wrong. There were. In 1909, a paleontologist 00:08:16.480 --> 00:08:18.959 named Earl Douglas, working for the Carnegie 00:08:18.959 --> 00:08:22.420 Museum, he found this beautiful, nearly complete 00:08:22.420 --> 00:08:25.860 apatosaurus skeleton. And right next to the neck, 00:08:25.920 --> 00:08:28.720 there was a skull. But it didn't look like a 00:08:28.720 --> 00:08:30.860 bulldog. What did it look like? It looked like 00:08:30.860 --> 00:08:34.460 a horse. long, slender, with a square snout and 00:08:34.460 --> 00:08:37.480 these pencil -like teeth just at the front. It 00:08:37.480 --> 00:08:39.879 looked almost identical to the skull of Diplodocus, 00:08:40.059 --> 00:08:42.980 just a bit heavier. So we have a Diplodocus -like 00:08:42.980 --> 00:08:45.259 head found right next to an Apatosaurus body. 00:08:45.600 --> 00:08:47.659 That seems pretty conclusive. It should have 00:08:47.659 --> 00:08:49.860 been. The director of the Carnegie Museum, William 00:08:49.860 --> 00:08:52.019 Holland, he was convinced. He wanted to mount 00:08:52.019 --> 00:08:54.899 the Diplodocus -style head. But, and here comes 00:08:54.899 --> 00:08:57.750 the politics again. Henry Fairfield Osborn, that 00:08:57.750 --> 00:08:59.730 powerful rival. The guy who kept Brontosaurus 00:08:59.730 --> 00:09:02.750 alive. The same guy. He insisted the boxy head 00:09:02.750 --> 00:09:05.129 was correct. He essentially bullied Holland into 00:09:05.129 --> 00:09:07.210 doubt. So what did Holland do? He did something 00:09:07.210 --> 00:09:09.909 incredibly petty and principled. He mounted the 00:09:09.909 --> 00:09:12.230 skeleton in the museum hall, but he left it headless. 00:09:12.470 --> 00:09:14.889 He just left the neck ending in a stump. For 00:09:14.889 --> 00:09:16.750 years. He basically said, if I can't put the 00:09:16.750 --> 00:09:18.350 right head on it, I won't put any head on it. 00:09:18.409 --> 00:09:20.649 That is a level of academic stubbornness I have 00:09:20.649 --> 00:09:23.230 to respect. Unfortunately, after Holland died... 00:09:23.389 --> 00:09:25.970 The museum caved. They put the wrong boxy skull 00:09:25.970 --> 00:09:28.870 on it anyway. Unbelievable. So when did we finally 00:09:28.870 --> 00:09:32.529 fix it? Not until the 1970s. Two researchers, 00:09:32.870 --> 00:09:35.490 John McIntosh and David Berman, they went back 00:09:35.490 --> 00:09:38.549 and did this incredible forensic work. They traced 00:09:38.549 --> 00:09:40.649 the original field notes, the maps, everything. 00:09:40.830 --> 00:09:44.330 And they proved conclusively that the skull Douglas 00:09:44.330 --> 00:09:47.409 found was the real Apatosaurus skull. So if you 00:09:47.409 --> 00:09:49.909 saw a drawing of a Brontosaurus before 1980, 00:09:50.250 --> 00:09:53.649 it was essentially a Chiamera. A mythological 00:09:53.649 --> 00:09:56.330 beast. Body of one dinosaur, head of another. 00:09:56.490 --> 00:09:58.470 A complete lie. Okay, so now that we've got the 00:09:58.470 --> 00:10:00.970 name back, sort of, and the head fixed, let's 00:10:00.970 --> 00:10:02.809 look at the actual animal. Biologically, what 00:10:02.809 --> 00:10:04.669 are we dealing with? Apatosaurus was built differently 00:10:04.669 --> 00:10:06.889 than its cousins, right? It was a tank. I mean, 00:10:06.909 --> 00:10:09.950 if Diplonicus was a suspension bridge long and 00:10:09.950 --> 00:10:13.090 Slender Apatosaurus was a fortress wall, it averaged 00:10:13.090 --> 00:10:16.009 about 21 to 23 meters long, but it was massive. 00:10:16.029 --> 00:10:19.809 We're talking 16 to 22 tons, with some individuals 00:10:19.809 --> 00:10:22.610 maybe pushing 30. And the neck is where it gets 00:10:22.610 --> 00:10:25.570 really interesting structurally. The notes mention 00:10:25.570 --> 00:10:29.129 deeply bifurcated vertebrae. Can you break that 00:10:29.129 --> 00:10:32.690 down? Bifurcated just means split. If you look 00:10:32.690 --> 00:10:35.629 at the neck vertebrae, the spines on top aren't 00:10:35.629 --> 00:10:37.929 a single blade. They're split into a V shape. 00:10:38.230 --> 00:10:42.279 This creates this wide... deep trough running 00:10:42.279 --> 00:10:44.840 all the way down the neck. And what goes in the 00:10:44.840 --> 00:10:47.659 trough? A massive ligament, the neutral ligament. 00:10:47.740 --> 00:10:49.779 Think of it like a giant rubber band that runs 00:10:49.779 --> 00:10:52.000 from the shoulders to the head, helping hold 00:10:52.000 --> 00:10:54.779 the neck up passively. It saves a ton of energy. 00:10:55.179 --> 00:10:57.559 But the really mind blowing thing about these 00:10:57.559 --> 00:10:59.740 bones is what was inside them. They were full 00:10:59.740 --> 00:11:03.059 of holes. Holes. Pseumaticity. They were honeycombed 00:11:03.059 --> 00:11:05.340 with air pockets, all connected to the respiratory 00:11:05.340 --> 00:11:07.580 system. Which connects to the bird comparison. 00:11:08.279 --> 00:11:10.610 Precisely. And this is a key take. away. You 00:11:10.610 --> 00:11:13.309 cannot build an animal this big using mammalian 00:11:13.309 --> 00:11:15.669 biology. It just doesn't work. Why not? Why couldn't 00:11:15.669 --> 00:11:17.909 a mammal get to 30 tons with a 30 -foot neck? 00:11:18.210 --> 00:11:21.169 It's the breathing. Mammals have tidal respiration. 00:11:21.509 --> 00:11:24.330 We breathe in, air goes into a dead end, our 00:11:24.330 --> 00:11:26.789 lungs, then we breathe out. That means there's 00:11:26.789 --> 00:11:30.009 always dead space, stale air left in the trachea. 00:11:30.009 --> 00:11:32.289 If your neck is 10 meters long, you'd just be 00:11:32.289 --> 00:11:35.789 rebreathing your own CO2. You'd suffocate. So 00:11:35.789 --> 00:11:38.159 how did apatosaurs do it? Almost certainly with 00:11:38.159 --> 00:11:41.100 a flow through system like modern birds, air 00:11:41.100 --> 00:11:43.519 flows in one direction through the lungs and 00:11:43.519 --> 00:11:45.320 into these air sac that permeate the skeleton. 00:11:45.580 --> 00:11:48.360 It allows for continuous oxygen extraction. It's 00:11:48.360 --> 00:11:50.840 highly efficient. It helps dump heat and it makes 00:11:50.840 --> 00:11:53.860 the skeleton incredibly light for its size. So 00:11:53.860 --> 00:11:57.139 this massive lumbering giant actually had a respiratory 00:11:57.139 --> 00:12:00.159 system more like a falcon than an elephant. Exactly. 00:12:00.159 --> 00:12:03.039 An air cooled, high performance biological machine. 00:12:03.279 --> 00:12:05.259 Which brings us to growth. I was stunned by the 00:12:05.259 --> 00:12:06.840 numbers here. These things. They started from 00:12:06.840 --> 00:12:08.740 eggs, so they started tiny, right? Tiny. The 00:12:08.740 --> 00:12:10.779 size of a small dog, maybe. And they grew to 00:12:10.779 --> 00:12:15.360 20 tons in how long? About 10 to 15 years to 00:12:15.360 --> 00:12:17.220 reach near adult size. That seems impossible. 00:12:17.620 --> 00:12:19.360 It does if you think of them as cold -blooded 00:12:19.360 --> 00:12:22.620 reptiles. But the bone histology, where we cut 00:12:22.620 --> 00:12:24.879 the bone and count the growth rings like a tree, 00:12:25.059 --> 00:12:27.840 it shows they were growing at an explosive rate. 00:12:28.139 --> 00:12:30.639 In their peak teenage years, they were putting 00:12:30.639 --> 00:12:34.759 on up to 5 ,000 kilograms a year. That's... Over 00:12:34.759 --> 00:12:37.500 13 kilos a day. Imagine gaining the weight of 00:12:37.500 --> 00:12:41.700 a toddler every single day for a year. You would 00:12:41.700 --> 00:12:43.440 just be an eating machine. That's all you'd do. 00:12:43.580 --> 00:12:46.820 That was their life. Fermentation vats on legs, 00:12:46.919 --> 00:12:49.460 processing massive amounts of low -quality vegetation 00:12:49.460 --> 00:12:52.559 just to fuel that metabolic furnace. Let's move 00:12:52.559 --> 00:12:55.220 to the other end of the animal, the tail. It's 00:12:55.220 --> 00:12:57.960 incredibly long, tapered like a whip. And I remember 00:12:57.960 --> 00:13:00.360 hearing about the supersonic theory in the 90s. 00:13:00.360 --> 00:13:03.450 Yes, this was a huge deal. In 1997, a computer 00:13:03.450 --> 00:13:05.690 model suggested the tip of the tail was thin 00:13:05.690 --> 00:13:07.429 and light enough that the animal could flick 00:13:07.429 --> 00:13:09.690 it fast enough to break the sound barrier. Creating 00:13:09.690 --> 00:13:12.590 a sonic boom. Over 200 decibels, like a cannon 00:13:12.590 --> 00:13:14.570 shot. The theory was they use it for defense 00:13:14.570 --> 00:13:18.049 or signaling. But I saw a 2020 study in our stack 00:13:18.049 --> 00:13:20.450 that challenges this. And this is a great example 00:13:20.450 --> 00:13:23.409 of physics versus biology. The model said the 00:13:23.409 --> 00:13:26.750 physics could work, but the 2020 study looked 00:13:26.750 --> 00:13:29.450 at the biology of it. They argued that if you 00:13:29.450 --> 00:13:32.129 actually snapped a tail made of flesh, bone, 00:13:32.330 --> 00:13:35.190 and skin at supersonic speeds, the stress would 00:13:35.190 --> 00:13:36.909 just shatter the vertebrae. Because they could 00:13:36.909 --> 00:13:39.690 do it once. Exactly. And then they'd have a broken 00:13:39.690 --> 00:13:42.850 necrotic tail. It's a biological structure, not 00:13:42.850 --> 00:13:45.570 a leather bullwhip. So if they weren't cracking 00:13:45.570 --> 00:13:48.629 them like whips, what were they doing with them? 00:13:48.970 --> 00:13:51.409 That study proposes something else, something 00:13:51.409 --> 00:13:56.090 gentler. A tactile organ. This is fascinating. 00:13:56.389 --> 00:13:59.049 The suggestion is they use their tails for touch. 00:13:59.269 --> 00:14:01.529 Like an antenna. Think about it. You're a 70 00:14:01.529 --> 00:14:03.590 -foot -long animal. Your head is way up front. 00:14:03.789 --> 00:14:05.690 How do you know where the rest of your herd is, 00:14:05.789 --> 00:14:08.149 especially if you're migrating in the dust or 00:14:08.149 --> 00:14:11.120 at dusk? You can't see behind you. Right. But 00:14:11.120 --> 00:14:13.200 if you have this long, sensitive tail that you 00:14:13.200 --> 00:14:15.200 can gently sweep back and forth, you can maintain 00:14:15.200 --> 00:14:17.419 physical contact with the animal behind you. 00:14:17.559 --> 00:14:20.139 Like holding hands in a line. Or like elephants 00:14:20.139 --> 00:14:23.419 using their trunks to touch each other. It turns 00:14:23.419 --> 00:14:26.740 the tail from a weapon of war into a tool for 00:14:26.740 --> 00:14:29.860 social cohesion. It implies they were tight -knit 00:14:29.860 --> 00:14:33.019 groups communicating through touch. I love that 00:14:33.019 --> 00:14:36.440 image. It completely reframes the animal from 00:14:36.440 --> 00:14:39.460 a solitary swamp monster to a social creature 00:14:39.460 --> 00:14:41.360 that needs to stay in touch with its family. 00:14:41.419 --> 00:14:43.419 It makes them real. And speaking of swamp bound, 00:14:43.620 --> 00:14:45.679 we used to think they lived in swamps because 00:14:45.679 --> 00:14:47.879 they were just too heavy for land. That's the 00:14:47.879 --> 00:14:51.460 old sluggish reptile bias. But we know from the 00:14:51.460 --> 00:14:53.879 geology of the Morrison Formation that it wasn't 00:14:53.879 --> 00:14:56.779 a swamp. It was semi -arid. Think of a Serengeti, 00:14:56.879 --> 00:14:59.539 but with ferns instead of grass. Wet seasons 00:14:59.539 --> 00:15:01.580 and dry seasons. Man, it was a crowded ecosystem. 00:15:02.179 --> 00:15:05.159 Very. They lived alongside Stegosaurus, Camarasaurus, 00:15:05.440 --> 00:15:07.980 and the apex predator Allosaurus. And Allosaurus 00:15:07.980 --> 00:15:10.480 was actively hunting them. We have evidence for 00:15:10.480 --> 00:15:12.919 it. There's an Apatosaurus hip bone with bite 00:15:12.919 --> 00:15:15.019 marks that perfectly matched the teeth of an 00:15:15.019 --> 00:15:17.879 Allosaurus. So yes, they were on the menu. But 00:15:17.879 --> 00:15:19.639 they weren't defenseless. See, on just size. 00:15:19.940 --> 00:15:23.580 They had one specific tool. A single, massive 00:15:23.580 --> 00:15:26.889 claw on their thumb. The other toes were blunt, 00:15:27.049 --> 00:15:30.110 but that thumb had this wicked, recurved claw. 00:15:30.649 --> 00:15:33.269 Could have been for grasping trees, but it'd 00:15:33.269 --> 00:15:36.049 also be a nasty surprise for a predator. There's 00:15:36.049 --> 00:15:40.070 one last debate. The posture. I always picture 00:15:40.070 --> 00:15:42.330 their heads held high, reaching for the treetops 00:15:42.330 --> 00:15:45.309 like a giraffe. But the sources are conflicted. 00:15:45.350 --> 00:15:48.470 This is the ostrich versus vacuum cleaner debate. 00:15:48.750 --> 00:15:51.350 Go on. One camp looks at living animals and says, 00:15:51.409 --> 00:15:53.610 look, almost all of them hold their necks up 00:15:53.610 --> 00:15:56.559 in an alert posture. They argue the joints allowed 00:15:56.559 --> 00:15:59.600 for a high vertical reach, the classic swan neck 00:15:59.600 --> 00:16:02.320 look. But the other side? The other side, using 00:16:02.320 --> 00:16:04.519 computer models, argued that the neck was actually 00:16:04.519 --> 00:16:07.240 quite stiff vertically. They claimed a patasaurus 00:16:07.240 --> 00:16:09.460 couldn't lift its head much higher than its shoulders. 00:16:09.659 --> 00:16:12.220 So it was just a low browser. Exactly. They suggest 00:16:12.220 --> 00:16:14.740 it stood in one spot and swept its neck side 00:16:14.740 --> 00:16:17.840 to side in a huge U -shape, mowing down ferns 00:16:17.840 --> 00:16:19.679 on the ground without moving its heavy body. 00:16:19.860 --> 00:16:22.379 A biological lawnmower. So what's the consensus 00:16:22.379 --> 00:16:25.360 now? It's leaning back toward a mix. The models 00:16:25.360 --> 00:16:27.799 probably missed the effect of cartilage, which 00:16:27.799 --> 00:16:30.279 would have made the neck more flexible. So they 00:16:30.279 --> 00:16:32.120 likely could lift their heads high when needed, 00:16:32.240 --> 00:16:34.059 but probably spent a lot of time feeding at mid 00:16:34.059 --> 00:16:36.279 to low levels. It really feels like every time 00:16:36.279 --> 00:16:38.759 we apply a new technology, the animal changes. 00:16:38.940 --> 00:16:41.419 That's the beauty of it. Apatosaurus is the perfect 00:16:41.419 --> 00:16:44.460 example. It started as a deceptive lizard because 00:16:44.460 --> 00:16:46.899 we didn't understand it. It lost its name. It 00:16:46.899 --> 00:16:49.120 lost its head. It was put in a swamp. And now? 00:16:49.200 --> 00:16:51.279 Now we see it as this terrestrial masterpiece. 00:16:52.529 --> 00:16:55.690 genus from Brontosaurus with a bird -like respiratory 00:16:55.690 --> 00:16:59.370 system growing at speeds that defy logic, living 00:16:59.370 --> 00:17:02.529 in complex social herds. It's a redemption arc 00:17:02.529 --> 00:17:05.670 150 years in the making. It really is. So I want 00:17:05.670 --> 00:17:07.029 to leave the listener with a little assignment. 00:17:07.210 --> 00:17:09.589 Next time you're in a museum looking up at that 00:17:09.589 --> 00:17:12.750 giant sauropod mount, do some detective work. 00:17:12.829 --> 00:17:14.930 Check the label, of course, but check the skull. 00:17:15.170 --> 00:17:17.869 Look at the face. Is it the boxy bulldog face 00:17:17.869 --> 00:17:21.390 or is it the slender horse -like face? Because 00:17:21.390 --> 00:17:23.970 even today, some museums haven't updated their 00:17:23.970 --> 00:17:26.630 mounts. And if you see that boxy head, you'll 00:17:26.630 --> 00:17:30.049 know you're looking at a piece of history. Just 00:17:30.049 --> 00:17:32.210 not natural history. You're looking at a mistake 00:17:32.210 --> 00:17:35.549 preserved in plaster. And maybe, just maybe, 00:17:35.650 --> 00:17:37.950 picture that tail not cracking like a gunshot, 00:17:38.069 --> 00:17:40.910 but gently brushing the flank of another dinosaur 00:17:40.910 --> 00:17:42.950 in the dark. Thanks for diving in with us. We'll 00:17:42.950 --> 00:17:43.609 see you on the next one.