WEBVTT 00:00:00.000 --> 00:00:02.080 Okay, I want you to picture the ultimate predator. 00:00:02.319 --> 00:00:06.639 For most of us, the brain goes straight to Tyrannosaurus 00:00:06.639 --> 00:00:09.580 Rex. It's the celebrity. It's the tank. Right. 00:00:09.699 --> 00:00:11.419 It's the bone crusher, the heavyweight champion, 00:00:11.539 --> 00:00:13.560 essentially. Exactly. But what if I told you 00:00:13.560 --> 00:00:16.780 that while T -Rex was still just a gleam in evolution's 00:00:16.780 --> 00:00:20.129 eye, there was another giant... roaming North 00:00:20.129 --> 00:00:23.570 Africa. A creature that was potentially longer 00:00:23.570 --> 00:00:26.510 than T -Rex had a skull that was actually bigger 00:00:26.510 --> 00:00:29.750 than the tyrant lizards. But, well, it was built 00:00:29.750 --> 00:00:31.489 on a completely different engineering philosophy. 00:00:31.510 --> 00:00:33.909 That is the key. The engineering. I mean, if 00:00:33.909 --> 00:00:37.350 T -Rex was a sledgehammer, this animal, it was 00:00:37.350 --> 00:00:39.509 a scalpel. A six -ton scalpel. And here's the 00:00:39.509 --> 00:00:42.109 twist. For over 50 years, this creature just... 00:00:42.429 --> 00:00:44.509 Didn't exist? Well, I mean, it didn't exist in 00:00:44.509 --> 00:00:46.829 museums. Right. The physical evidence for it 00:00:46.829 --> 00:00:48.909 was wiped off the face of the earth in a single 00:00:48.909 --> 00:00:51.109 night during World War II. It is probably the 00:00:51.109 --> 00:00:53.509 most tragic ghost story in all of paleontology. 00:00:53.729 --> 00:00:55.670 But, you know, it's also a story of resurrection. 00:00:55.950 --> 00:00:58.490 It really is. Today we are doing a deep dive 00:00:58.490 --> 00:01:01.049 into the shark -toothed giant of the Sahara, 00:01:01.250 --> 00:01:04.670 Carcharodontosaurus. Carcharodontosaurus. That 00:01:04.670 --> 00:01:07.670 is a mouthful. I feel like I need a running start 00:01:07.670 --> 00:01:10.590 just to say it. It is a bit of a tongue twister. 00:01:11.819 --> 00:01:14.260 Like all good scientific names, it tells you 00:01:14.260 --> 00:01:15.879 exactly what you're looking at. It breaks down 00:01:15.879 --> 00:01:19.200 from the Greek. You have karcharos, which means 00:01:19.200 --> 00:01:22.840 jagged or sharp. Otis means tooth. And soros, 00:01:22.840 --> 00:01:26.280 obviously, is lizard. So, jagged -toothed lizard. 00:01:26.620 --> 00:01:29.200 Or, as it's usually translated, the shark -toothed 00:01:29.200 --> 00:01:32.269 lizard. And that isn't just a poetic flourish. 00:01:32.370 --> 00:01:36.370 The name specifically references the genus Carcharodon. 00:01:36.390 --> 00:01:38.129 The great white. The great white shark, exactly. 00:01:38.569 --> 00:01:40.730 The scientist who named it looked at its teeth 00:01:40.730 --> 00:01:43.790 and just saw this striking resemblance to the 00:01:43.790 --> 00:01:45.810 ocean's perfect predator. We are absolutely going 00:01:45.810 --> 00:01:47.329 to get into the mechanics of those teeth because 00:01:47.329 --> 00:01:49.750 they are terrifying. But first, we have to address 00:01:49.750 --> 00:01:51.790 this ghost story. You mentioned the evidence 00:01:51.790 --> 00:01:54.290 was destroyed. I mean, how do you lose a 40 -foot 00:01:54.290 --> 00:01:57.780 dinosaur? You lose it in the fog of war. The 00:01:57.780 --> 00:02:00.719 story really begins in this golden age of exploration. 00:02:01.099 --> 00:02:03.439 The first hints actually popped up in Algeria 00:02:03.439 --> 00:02:06.799 in 1924. Two French paleontologists, Gabaret 00:02:06.799 --> 00:02:10.259 and Savournot, they found two massive serrated 00:02:10.259 --> 00:02:13.840 teeth. They knew they had a large theropod, but 00:02:13.840 --> 00:02:15.759 they didn't have enough bone to really define 00:02:15.759 --> 00:02:18.620 a new species. So they did what everyone did 00:02:18.620 --> 00:02:20.680 back then. They threw it into the wastebasket, 00:02:20.680 --> 00:02:24.439 genus. Yep. Let me guess. Megalosaurus. You got 00:02:24.439 --> 00:02:27.319 it. Megalosaurus saharicus. For a long time, 00:02:27.379 --> 00:02:29.620 Megalosaurus was just the label for big meat 00:02:29.620 --> 00:02:31.960 eater. Not sure what else, but the real breakthrough 00:02:31.960 --> 00:02:34.939 happened in Egypt with a German paleontologist 00:02:34.939 --> 00:02:37.900 named Ernst Stromer. Stromer is a legend in the 00:02:37.900 --> 00:02:40.900 field. He is. In 1914, he and his collector, 00:02:41.060 --> 00:02:43.219 Richard Markgraf, were digging in the Baharia 00:02:43.219 --> 00:02:45.740 Formation, and they uncovered a partial skeleton 00:02:45.740 --> 00:02:48.379 that was clearly something unique. But look at 00:02:48.379 --> 00:02:52.240 the date. 1914. Right. World War I. Precisely. 00:02:52.509 --> 00:02:54.550 Stromer was German. Right. Egypt was effectively 00:02:54.550 --> 00:02:57.069 under British control, so the geopolitical tension 00:02:57.069 --> 00:02:59.810 was through the roof. I can imagine. Because 00:02:59.810 --> 00:03:01.710 of the war and all the chaos that came after, 00:03:01.810 --> 00:03:03.909 those bones couldn't even be shipped to Munich 00:03:03.909 --> 00:03:06.830 until 1922. And it took Stromer another nine 00:03:06.830 --> 00:03:10.229 years to clean, prep, and analyze them. Finally, 00:03:10.270 --> 00:03:13.990 in 1931, he publishes his description. He sees 00:03:13.990 --> 00:03:16.949 those distinct shark -like serrations, and he 00:03:16.949 --> 00:03:20.729 officially names it Carchorodontosaurus. So 1931, 00:03:20.870 --> 00:03:23.289 the skeleton is in the Paleontologist Museum 00:03:23.289 --> 00:03:25.909 in Munich. It's a crown jewel. We have the proof. 00:03:26.110 --> 00:03:28.870 We did, for a time. But then came the Second 00:03:28.870 --> 00:03:31.289 World War. Yeah. Stromer actually pleaded with 00:03:31.289 --> 00:03:33.409 the museum directors to move the fossils to a 00:03:33.409 --> 00:03:36.150 safe location, like a salt mine, to protect them 00:03:36.150 --> 00:03:38.310 from air raids. That seems sensible. It was. 00:03:38.349 --> 00:03:40.469 But because Stromer was an outspoken critic of 00:03:40.469 --> 00:03:43.669 the Nazi regime, his requests were ignored. Wow. 00:03:43.750 --> 00:03:46.490 So it wasn't just... Just bad luck. That's political. 00:03:46.710 --> 00:03:50.770 It was. And on the night of April 24, 1944, the 00:03:50.770 --> 00:03:53.150 Royal Air Force conducted a massive bombing raid 00:03:53.150 --> 00:03:55.729 on Munich. The museum took a direct hit. Oh, 00:03:55.729 --> 00:03:58.469 no. And the holotype, the single specimen that 00:03:58.469 --> 00:04:01.349 defined the species, was incinerated. Gone. Turned 00:04:01.349 --> 00:04:03.590 to ash. The only things that survived were Stromer's 00:04:03.590 --> 00:04:05.289 scientific drawings, some grainy photographs, 00:04:05.569 --> 00:04:07.990 and a cast of the brain cavity. For the next 00:04:07.990 --> 00:04:10.310 half century, Carcharodontosaurus was effectively 00:04:10.310 --> 00:04:13.430 a myth. A ghost. A name in a textbook with nobody 00:04:13.430 --> 00:04:16.910 to back it up. Until the 1990s. This seems to 00:04:16.910 --> 00:04:19.089 be when everything in dinosaur science gets a 00:04:19.089 --> 00:04:21.290 reboot. The renaissance of paleontology, yeah. 00:04:21.910 --> 00:04:25.310 In 1995, Paul Serino from the University of Chicago 00:04:25.310 --> 00:04:29.250 led an expedition to the Khembeds in Morocco. 00:04:29.790 --> 00:04:32.269 He wasn't specifically looking to resurrect Stromer's 00:04:32.269 --> 00:04:34.370 lost giant, but that's exactly what happened. 00:04:34.509 --> 00:04:36.689 They found a skull. And this wasn't just a few 00:04:36.689 --> 00:04:38.629 fragments they glued together. No, no, this is 00:04:38.629 --> 00:04:42.389 a massive, largely incomplete, but... diagnostic 00:04:42.389 --> 00:04:45.730 skull. This specimen became the neotype. It allowed 00:04:45.730 --> 00:04:48.290 scientists to officially redefine Cartridontosaurus 00:04:48.290 --> 00:04:50.850 saharicus and, you know, bring it back from the 00:04:50.850 --> 00:04:52.649 dead. So thanks to Serino and his team, we can 00:04:52.649 --> 00:04:54.550 actually look at this thing again. Let's talk 00:04:54.550 --> 00:04:56.529 about the tail of the tape. Everyone always wants 00:04:56.529 --> 00:05:00.069 to know. Was it bigger than T. rex? Ah, the eternal 00:05:00.069 --> 00:05:02.269 playground debate. It's surprisingly complex. 00:05:02.470 --> 00:05:05.810 The current consensus estimates place Carcharodontosaurus 00:05:05.810 --> 00:05:08.910 between about 12 and 12 .5 meters in length. 00:05:09.029 --> 00:05:11.689 So that's roughly 39 to 41 feet. And weight, 00:05:11.730 --> 00:05:13.670 why? Somewhere in the range of 5 to 7 metric 00:05:13.670 --> 00:05:15.610 tons. So it's definitely in the same weight class 00:05:15.610 --> 00:05:17.899 as T. rex. Oh, absolutely. It's right up there. 00:05:17.939 --> 00:05:20.399 It's competing for the title of largest theropod 00:05:20.399 --> 00:05:23.699 alongside T. rex, Giganotosaurus from South America, 00:05:23.879 --> 00:05:26.519 and, of course, Spinosaurus. Right. In fact, 00:05:26.519 --> 00:05:28.699 when Serino first described the new skull, he 00:05:28.699 --> 00:05:32.410 estimated it 1 .6 meters long. For context, that 00:05:32.410 --> 00:05:34.629 is longer than the skull of Sue, the famous Field 00:05:34.629 --> 00:05:37.769 Museum T -Rex. That is a massive head, five feet 00:05:37.769 --> 00:05:40.490 of skull. Later studies, specifically by Carano 00:05:40.490 --> 00:05:43.149 in 2012, they dialed that estimate back a bit 00:05:43.149 --> 00:05:46.709 to about 1 .42 meters. But really, regardless 00:05:46.709 --> 00:05:48.550 of a few centimeters here or there, we're dealing 00:05:48.550 --> 00:05:50.910 with a predator that pushed the biological limits 00:05:50.910 --> 00:05:54.850 of size. But, and this is the crucial part, it 00:05:54.850 --> 00:05:56.750 was built completely differently than a tyrannosaur. 00:05:57.120 --> 00:05:59.139 You mentioned it earlier, the difference between 00:05:59.139 --> 00:06:01.579 a sledgehammer and a scalpel. Let's unpack that. 00:06:01.720 --> 00:06:03.800 If I'm looking at the skull of a T -Rex versus 00:06:03.800 --> 00:06:06.579 a cartridodontosaurus, what am I seeing? If you 00:06:06.579 --> 00:06:09.100 look at a T -Rex, you see width. You see thick, 00:06:09.120 --> 00:06:11.759 fused bones designed to absorb massive shock. 00:06:11.899 --> 00:06:14.240 There's a bone pressure. Cartridodontosaurus, 00:06:14.459 --> 00:06:16.620 on the other hand, has a skull that is, well, 00:06:16.759 --> 00:06:20.649 it's narrow and triangular. And it is... incredibly 00:06:20.649 --> 00:06:23.290 lightweight. Lightweight for a six -ton animal. 00:06:23.529 --> 00:06:26.649 Relatively speaking, yes. The skull is filled 00:06:26.649 --> 00:06:29.629 with what are called fenestri. Which are? A fancy 00:06:29.629 --> 00:06:32.529 Latin word for windows. These are large openings 00:06:32.529 --> 00:06:35.649 in the skull bones. They're also deep depressions 00:06:35.649 --> 00:06:39.689 called fossae. Now, these structures house muscles, 00:06:39.829 --> 00:06:42.949 sure, but their primary job was to reduce mass. 00:06:43.230 --> 00:06:45.689 It's like an airplane fuselage, right? Maximum 00:06:45.689 --> 00:06:49.319 strength, minimum weight. Exactly. If Carcharodontosaurus 00:06:49.319 --> 00:06:52.480 had a solid skull like a T -Rex, it probably 00:06:52.480 --> 00:06:53.860 wouldn't have been able to lift its head off 00:06:53.860 --> 00:06:55.259 the ground. That makes sense. It's all about 00:06:55.259 --> 00:06:57.240 optimization. I also read something about the 00:06:57.240 --> 00:07:00.879 nose having a rugose texture. That sounds medical. 00:07:01.220 --> 00:07:03.699 It does sound a bit clinical. In paleontology, 00:07:03.779 --> 00:07:06.490 rugose just means wrinkly or bumpy. The nasal 00:07:06.490 --> 00:07:09.689 bones had this rough textured surface. And this 00:07:09.689 --> 00:07:12.470 strongly suggests that in life, those bones were 00:07:12.470 --> 00:07:14.990 covered in keratin sheets, the same material 00:07:14.990 --> 00:07:17.370 as your fingernails or a bird's beak. So it wasn't 00:07:17.370 --> 00:07:19.629 just skin and scale. It had some kind of structure 00:07:19.629 --> 00:07:21.930 on its face. Very likely. It probably had these 00:07:21.930 --> 00:07:25.050 hard horn -like ridges or crests running down 00:07:25.050 --> 00:07:27.269 its snout. It would have given the animal a very 00:07:27.269 --> 00:07:30.389 distinct, very menacing profile. Okay, let's 00:07:30.389 --> 00:07:32.990 get to the weaponry, the teeth, the shark connection. 00:07:33.600 --> 00:07:35.860 You said they aren't bone crushers. Absolutely 00:07:35.860 --> 00:07:38.459 not. And this is the most fascinating piece of 00:07:38.459 --> 00:07:41.240 the puzzle. A T -Rex tooth is like a banana. 00:07:41.620 --> 00:07:45.639 It's round, thick, with deep roots. It's designed 00:07:45.639 --> 00:07:47.800 to punch through armor and bone without snapping. 00:07:49.000 --> 00:07:52.220 Carcharodontosaurus teeth, they're blades. They 00:07:52.220 --> 00:07:54.300 are laterally compressed, meaning they're flattened 00:07:54.300 --> 00:07:56.839 side to side. How flat are we talking? Extremely. 00:07:56.860 --> 00:07:59.699 A large tooth might be 6 .5 centimeters tall, 00:07:59.879 --> 00:08:02.899 but only about one centimeter thick. Wow. That 00:08:02.899 --> 00:08:06.079 sounds fragile. It is, structurally. But it's 00:08:06.079 --> 00:08:08.920 sharp. The serrations are incredibly fine. We're 00:08:08.920 --> 00:08:11.560 talking 18 to 20 serrations per centimeter. It 00:08:11.560 --> 00:08:14.240 is effectively a steak knife. Okay. But nature 00:08:14.240 --> 00:08:17.000 added this brilliant reinforcement feature. They 00:08:17.000 --> 00:08:18.720 have what are called enamel wrinkles. Enamel 00:08:18.720 --> 00:08:20.600 wrinkles? I've never heard of that. It's a specific 00:08:20.600 --> 00:08:23.420 adaptation. Near the serrations, the enamel actually 00:08:23.420 --> 00:08:25.779 bows and ripples. Think of it like the corrugation 00:08:25.779 --> 00:08:27.920 in a cardboard box or a sheet of steel roofing. 00:08:27.939 --> 00:08:30.620 That waviness adds structural integrity. It stops 00:08:30.620 --> 00:08:32.620 cracks from spreading across the tooth. So it's 00:08:32.620 --> 00:08:34.980 a way to keep a thin, sharp blade from just snapping 00:08:34.980 --> 00:08:37.200 the moment it hits something hard. Precisely. 00:08:37.399 --> 00:08:40.519 But it still dictates behavior. You cannot bite 00:08:40.519 --> 00:08:43.139 into a femur with these teeth. They would shatter. 00:08:43.259 --> 00:08:45.600 So if it can't crunch bone, how does it kill 00:08:45.600 --> 00:08:48.159 a 40 -foot sauropod? We have to look at the bite 00:08:48.159 --> 00:08:51.100 force. Estimates for Carcharodontosaurus sit 00:08:51.100 --> 00:08:54.620 between about 11 ,000 and 25 ,000 newtons. Which, 00:08:54.659 --> 00:08:56.700 to be fair, is a lot. That would ruin my day. 00:08:56.980 --> 00:08:59.659 Oh, it would snap you in half. Yeah. But compared 00:08:59.659 --> 00:09:02.879 to T -Rex, which was pushing 35 ,000, maybe even 00:09:02.879 --> 00:09:06.960 57 ,000 newtons, it's significantly weaker. The 00:09:06.960 --> 00:09:08.820 skull structure, with all those weight -saving 00:09:08.820 --> 00:09:10.980 windows, just couldn't handle the stress of a 00:09:10.980 --> 00:09:13.519 clamp -and -shake maneuver. So paleontologists 00:09:13.519 --> 00:09:16.299 believe it used a slash -and -bleed tactic. Slash 00:09:16.299 --> 00:09:20.429 -and -bleed, that sounds... It is. The hypothesis 00:09:20.429 --> 00:09:22.649 is that Cartridontosaurus would use its long 00:09:22.649 --> 00:09:25.370 neck to strike quickly, raking those serrated 00:09:25.370 --> 00:09:27.769 teeth across the soft tissue of its prey, the 00:09:27.769 --> 00:09:30.309 flank, the neck, the underbelly. It would open 00:09:30.309 --> 00:09:32.830 up these massive long wounds to cause rapid blood 00:09:32.830 --> 00:09:35.629 loss, exsanguination. So it's not trying to overpower 00:09:35.629 --> 00:09:38.470 the prey instantly. It's inflicting a fatal wound 00:09:38.470 --> 00:09:40.730 and then backing off. Exactly. It's a hit -and 00:09:40.730 --> 00:09:42.769 -run attack. And we have more evidence that it 00:09:42.769 --> 00:09:45.820 wasn't a wrestler. A 2015 study by Henderson 00:09:45.820 --> 00:09:48.220 and Nichols analyzed the lifting strength of 00:09:48.220 --> 00:09:50.539 the neck and jaws. Lifting strength? Like how 00:09:50.539 --> 00:09:52.159 much weight it could pick up off the ground? 00:09:52.440 --> 00:09:54.879 Precisely. And they found that a single adult 00:09:54.879 --> 00:09:59.559 could lift about 424 kilograms. 424 kilos? That's 00:09:59.559 --> 00:10:03.220 roughly 935 pounds. Which sounds impressive to 00:10:03.220 --> 00:10:05.639 us, you know, as humans. But in the dinosaur 00:10:05.639 --> 00:10:08.740 world, it's surprisingly low. For comparison, 00:10:08.899 --> 00:10:12.190 a sauropod, a plant eater, of a similar body 00:10:12.190 --> 00:10:15.450 size, like Lamisaurus, had neck muscles capable 00:10:15.450 --> 00:10:17.929 of lifting double that. So Cartridonosaurus really 00:10:17.929 --> 00:10:19.830 wasn't built for heavy lifting. It wasn't dragging 00:10:19.830 --> 00:10:22.669 carcasses around or tossing animals. No, it was 00:10:22.669 --> 00:10:24.889 a precision striker. And speaking of precision, 00:10:25.129 --> 00:10:27.870 we need to talk about its eyes. Because for a 00:10:27.870 --> 00:10:29.769 predator that relies on striking, you'd think 00:10:29.769 --> 00:10:31.389 it would have eagle vision. I'm missing there's 00:10:31.389 --> 00:10:35.149 a butt coming. A big butt. A study by Kent Stevens 00:10:35.149 --> 00:10:38.690 in 2006 modeled its field of view. And because 00:10:38.690 --> 00:10:41.269 the snout is so long and narrow, it actually 00:10:41.269 --> 00:10:43.590 blocks a significant portion of the forward view. 00:10:44.370 --> 00:10:47.730 It had very limited binocular vision, only about 00:10:47.730 --> 00:10:50.490 40 degrees of overlap where it could see in 3D. 00:10:50.669 --> 00:10:52.730 So it had terrible depth perception. Compared 00:10:52.730 --> 00:10:56.110 to a T -Rex or a raptor, yes. This suggests it 00:10:56.110 --> 00:10:58.049 wasn't running down prey over long distances 00:10:58.049 --> 00:11:01.029 where judging that gap is crucial. Instead, it 00:11:01.029 --> 00:11:03.389 likely relied on something called motion parallax. 00:11:03.610 --> 00:11:05.669 That's a thing birds do, right? Bobbing their 00:11:05.669 --> 00:11:08.690 heads. Right, or like a lizard. By moving his 00:11:08.690 --> 00:11:10.850 head side to side, objects at different distances 00:11:10.850 --> 00:11:13.129 move at different speeds relative to the background. 00:11:13.689 --> 00:11:16.350 It helps you judge distance without binocular 00:11:16.350 --> 00:11:19.049 overlap. This fits the profile of an ambush predator. 00:11:19.409 --> 00:11:21.509 Lying in wait. Lying in wait in the tree line 00:11:21.509 --> 00:11:23.590 or the mangroves, waiting for a silhouette to 00:11:23.590 --> 00:11:25.990 cross its path and then strike. That image actually 00:11:25.990 --> 00:11:28.210 brings us perfectly to the setting. We have to 00:11:28.210 --> 00:11:30.269 talk about the danger zone because everything 00:11:30.269 --> 00:11:32.370 I read about Cretaceous North Africa makes it 00:11:32.370 --> 00:11:34.070 sound like the most dangerous place that has 00:11:34.070 --> 00:11:36.190 ever existed on this planet. It's certainly up 00:11:36.190 --> 00:11:38.250 there. We're in the Santa Manian stage about 00:11:38.250 --> 00:11:41.549 100 to 94 million years ago. North Africa wasn't 00:11:41.549 --> 00:11:44.490 a desert then. It was a lush, tropical network 00:11:44.490 --> 00:11:47.909 of mangrove forests, tidal flats, and wetlands 00:11:47.909 --> 00:11:50.230 bordering the Tethys Sea. And it was crowded. 00:11:50.509 --> 00:11:53.070 Incredibly crowded. In fact, this ecosystem presents 00:11:53.070 --> 00:11:56.090 a famous problem in paleontology known as Stromer's 00:11:56.090 --> 00:11:58.389 riddle. Stromer's riddle? Okay, what's the riddle? 00:11:58.509 --> 00:12:01.409 It's the ratio. In almost every ecosystem, modern 00:12:01.409 --> 00:12:04.590 or ancient, you have a large base of herbivores, 00:12:04.730 --> 00:12:08.330 the prey, and a very small number of apex carnivores. 00:12:08.690 --> 00:12:12.059 Think of the Serengeti. Tons of wildebeest. Very 00:12:12.059 --> 00:12:14.820 few lions. Right. But in the Kem Kem beds in 00:12:14.820 --> 00:12:17.019 Baharia, the fossil record shows an inverted 00:12:17.019 --> 00:12:20.139 pyramid. There's a weirdly high number of giant 00:12:20.139 --> 00:12:21.820 carnivores. Who are the neighbors we're talking 00:12:21.820 --> 00:12:24.659 about? We had Carcharodontosaurus. You had Spinosaurus, 00:12:24.779 --> 00:12:27.559 which was even larger physically. You had Deltadromeus, 00:12:27.620 --> 00:12:30.639 another large theropod. You had crocodile cousins 00:12:30.639 --> 00:12:33.399 like Stomatosus and Elosuchus that were the size 00:12:33.399 --> 00:12:36.279 of school buses. It's a monster mash. How does 00:12:36.279 --> 00:12:38.720 an ecosystem even support that many apex predators 00:12:38.720 --> 00:12:40.840 without them just eating each other into extinction? 00:12:41.179 --> 00:12:43.580 That is the riddle. And the answer appears to 00:12:43.580 --> 00:12:46.240 be niche partitioning. Dividing up the buffet. 00:12:46.720 --> 00:12:49.399 Exactly. And we don't just have to guess at this. 00:12:49.519 --> 00:12:52.059 We have the chemistry to prove it. Scientists 00:12:52.059 --> 00:12:54.820 have analyzed the calcium and oxygen isotopes 00:12:54.820 --> 00:12:57.399 in the teeth of these animals. You are what you 00:12:57.399 --> 00:13:01.179 eat. Literally. The isotope values in Spinosaurus 00:13:01.179 --> 00:13:04.419 teeth match those of aquatic animals. They were 00:13:04.419 --> 00:13:08.460 eating fish giant sawfish like Onchopristus coelacanths. 00:13:08.559 --> 00:13:10.919 They were spending their time in the river systems. 00:13:11.139 --> 00:13:13.909 And our shark -toothed friend. Carcharodontosaurus 00:13:13.909 --> 00:13:16.230 isotopes are strictly terrestrial. They drank 00:13:16.230 --> 00:13:18.889 from the river shore, but they fed on land. They 00:13:18.889 --> 00:13:20.649 were hunting the sauropods like Robachosaurus 00:13:20.649 --> 00:13:23.590 and the Iguanodons. So even though they lived 00:13:23.590 --> 00:13:25.929 in the same zip code, they weren't ordering off 00:13:25.929 --> 00:13:28.529 the same menu. I love that. So Spinosaurus gets 00:13:28.529 --> 00:13:30.710 the water. Carcharodontosaurus gets the land. 00:13:30.929 --> 00:13:33.029 Just staying out of each other's way. It's a 00:13:33.029 --> 00:13:35.730 professional courtesy among monsters. Avoiding 00:13:35.730 --> 00:13:38.070 conflict prevents injury. And for a predator, 00:13:38.250 --> 00:13:41.059 injury usually means death. Now, I want to zoom 00:13:41.059 --> 00:13:43.000 out a bit on the family tree. We've mentioned 00:13:43.000 --> 00:13:44.820 Giganotosaurus a couple of times, which lived 00:13:44.820 --> 00:13:47.360 in South America. How are they related? They 00:13:47.360 --> 00:13:49.539 are very close cousins. They both belong to the 00:13:49.539 --> 00:13:53.360 family Carcharodontosauridae. In fact, Carcharodontosaurus 00:13:53.360 --> 00:13:55.879 is more closely related to Giganotosaurus and 00:13:55.879 --> 00:13:58.750 Mapposaurus from Argentina. than it is to any 00:13:58.750 --> 00:14:00.870 North American dinosaur like Allosaurus. But 00:14:00.870 --> 00:14:03.250 wait, South America and Africa are separated 00:14:03.250 --> 00:14:05.870 by the Atlantic Ocean? They are now. But this 00:14:05.870 --> 00:14:08.730 relationship is a smoking gun for plate tectonics. 00:14:08.870 --> 00:14:11.129 It proves that the separation of these continents 00:14:11.129 --> 00:14:14.230 was recent enough, geologically speaking, that 00:14:14.230 --> 00:14:16.730 these animals shared a common ancestor on the 00:14:16.730 --> 00:14:19.659 supercontinent Gondwana. So before the Atlantic 00:14:19.659 --> 00:14:22.500 unzipped the continents, this one family of shark 00:14:22.500 --> 00:14:25.179 -toothed giants ruled the entire southern hemisphere. 00:14:25.539 --> 00:14:27.639 Essentially, yes. It was a transcontinental dynasty. 00:14:28.179 --> 00:14:30.600 Before we wrap up, I need to ask about a controversy. 00:14:30.960 --> 00:14:33.279 I saw on the notes there might be a second species, 00:14:33.759 --> 00:14:37.539 Cartrodontosaurus igedensis. Ah, yes. In 2007, 00:14:37.799 --> 00:14:40.639 fossils found in Niger were described as a new 00:14:40.639 --> 00:14:43.580 species, igedensis. It was thought to be slightly 00:14:43.580 --> 00:14:46.000 smaller than Saharicus. But science has never 00:14:46.000 --> 00:14:49.539 settled. Recent studies, some as late as 2016, 00:14:49.879 --> 00:14:53.580 even proposals for 2025, have reexamined those 00:14:53.580 --> 00:14:56.519 fossils. The argument now is that the materials 00:14:56.519 --> 00:14:59.539 is too fragmentary to be sure. Some paleontologists 00:14:59.539 --> 00:15:01.340 think those bones might actually belong to a 00:15:01.340 --> 00:15:03.940 different animal entirely, maybe Sigilmassosaurus, 00:15:04.259 --> 00:15:06.120 or they just fall within the normal variation 00:15:06.120 --> 00:15:09.779 of Saharicus. So for now, Cartridontosaurus Saharicus 00:15:09.779 --> 00:15:12.980 is the one true king of the genus. It seems that 00:15:12.980 --> 00:15:15.299 way. It's a good reminder that paleontology is 00:15:15.299 --> 00:15:17.600 a puzzle where half the pieces are missing and 00:15:17.600 --> 00:15:20.240 the picture on the box keeps changing. So let's 00:15:20.240 --> 00:15:22.720 recap. We have a 40 -foot predator that rivals 00:15:22.720 --> 00:15:25.360 T -Rex in size but is built like a fighter jet. 00:15:25.710 --> 00:15:27.649 It had a lightweight skull, teeth reinforced 00:15:27.649 --> 00:15:29.870 like corrugated steel to slice rather than crush, 00:15:30.090 --> 00:15:32.389 and it lived in a swamp full of other nightmares. 00:15:32.549 --> 00:15:34.710 And perhaps most importantly, it's a species 00:15:34.710 --> 00:15:36.929 that we almost lost forever to the flames of 00:15:36.929 --> 00:15:39.389 World War II, only to find it again in the desert 00:15:39.389 --> 00:15:42.250 sands 50 years later. It's an incredible story 00:15:42.250 --> 00:15:45.509 of resilience. Now, usually we end with a fun 00:15:45.509 --> 00:15:48.309 fact, but the expert note here raises a really 00:15:48.309 --> 00:15:50.990 provocative question. We spend all this time 00:15:50.990 --> 00:15:53.639 debating, you know. Who would win in a fight, 00:15:53.779 --> 00:15:57.200 T -Rex or Carcharodontosaurus? The classic schoolyard 00:15:57.200 --> 00:15:59.120 scenario. But you wanted to flip that on its 00:15:59.120 --> 00:16:01.779 head. I do. Think about the fragility we discussed. 00:16:02.059 --> 00:16:05.580 The lightweight skull. The thin teeth. The lack 00:16:05.580 --> 00:16:09.120 of lifting power. Why would nature evolve a predator 00:16:09.120 --> 00:16:12.720 that massive with a head that delicate? You'd 00:16:12.720 --> 00:16:15.299 think bigger means heavier, stronger, bulkier. 00:16:15.519 --> 00:16:18.200 Exactly. But Carcharodontosaurus teaches us that 00:16:18.200 --> 00:16:20.220 being the king isn't always about brute force. 00:16:20.440 --> 00:16:23.590 It's the precision. It's about efficiency. In 00:16:23.590 --> 00:16:26.049 a crowded ecosystem, you don't need to be a tank 00:16:26.049 --> 00:16:28.549 if being a fencer works better. I love that image. 00:16:28.590 --> 00:16:30.710 The fencer of the Cretaceous. It didn't need 00:16:30.710 --> 00:16:33.350 to crush bones. It just needed to be fast, sharp, 00:16:33.450 --> 00:16:36.009 and accurate. Precisely. It challenges our bias 00:16:36.009 --> 00:16:39.990 that strongest always means best. Sometimes the 00:16:39.990 --> 00:16:41.710 most specialized design is the one that wins. 00:16:41.870 --> 00:16:44.470 A profound thought to end on. That is all the 00:16:44.470 --> 00:16:46.470 time we have for this deep dive into the shark 00:16:46.470 --> 00:16:48.830 tooth giant. Thanks for helping us unpack this 00:16:48.830 --> 00:16:51.149 monster. My pleasure. And thank you for listening. 00:16:51.769 --> 00:16:54.309 Keep asking questions and we'll see you on the 00:16:54.309 --> 00:16:55.309 next deep dive.