WEBVTT 00:00:00.000 --> 00:00:02.080 Welcome back to the Deep Dive. We're doing something 00:00:02.080 --> 00:00:04.700 a little different today. Oh, yeah. Usually, 00:00:04.799 --> 00:00:07.200 you know, we tackle a specific paper, a news 00:00:07.200 --> 00:00:10.119 event, or maybe a complex historical figure. 00:00:10.580 --> 00:00:13.699 Today, we are tackling a silhouette. A silhouette. 00:00:13.980 --> 00:00:17.059 That sounds a little ominous. You know exactly 00:00:17.059 --> 00:00:18.960 the one I mean. Yeah. If you grew up with a bucket 00:00:18.960 --> 00:00:21.039 of plastic dinosaurs, and I think everyone listening 00:00:21.039 --> 00:00:24.140 probably did, you had this one. It wasn't the 00:00:24.140 --> 00:00:26.800 T -Rex and it wasn't the Triceratops. It was 00:00:26.800 --> 00:00:29.719 the duck -billed one with that long curved tube 00:00:29.719 --> 00:00:32.240 sticking out the back of its head. Ah, yeah. 00:00:32.359 --> 00:00:34.000 The one that looks like it's wearing a giant 00:00:34.000 --> 00:00:36.439 piece of macaroni on its head. A boomerang. Yeah. 00:00:36.460 --> 00:00:38.520 Yeah, macaroni. That's a great way to put it. 00:00:38.579 --> 00:00:41.600 The Parasaurovus. That is the one. And looking 00:00:41.600 --> 00:00:44.119 at the stack of research we have today, and I 00:00:44.119 --> 00:00:46.340 mean, it's... everything from the original field 00:00:46.340 --> 00:00:49.659 notes in the 1920s to acoustic physics modeling 00:00:49.659 --> 00:00:52.880 from Sandia National Labs, I realized something. 00:00:53.140 --> 00:00:55.859 This dinosaur is probably one of the most recognized 00:00:55.859 --> 00:00:58.380 yet least understood animals in the fossil record. 00:00:59.299 --> 00:01:02.359 We all know the shape, but we kind of treat it 00:01:02.359 --> 00:01:04.719 like a piece of clip art. It's just the one with 00:01:04.719 --> 00:01:06.579 the weird head. I think that's a really fair 00:01:06.579 --> 00:01:09.719 assessment. For a long time, even within paleontology, 00:01:09.900 --> 00:01:13.299 Parasaurolophus was sort of... It was relegated 00:01:13.299 --> 00:01:16.680 to being background scenery. It's the cow grazing 00:01:16.680 --> 00:01:18.579 in the swamp while the T -Rex does all the cool 00:01:18.579 --> 00:01:20.700 stuff in the foreground. It's the extra in the 00:01:20.700 --> 00:01:23.560 movie of the Cretaceous. Exactly. So the mission 00:01:23.560 --> 00:01:26.000 for this deep dive is to drag this animal out 00:01:26.000 --> 00:01:28.420 of the background. I want to stop looking at 00:01:28.420 --> 00:01:30.959 it as a plastic toy. And start understanding 00:01:30.959 --> 00:01:34.060 it as a biological machine. Because when you 00:01:34.060 --> 00:01:36.200 actually dig into the mechanics of this thing, 00:01:36.280 --> 00:01:38.840 how it ate, how it moved, and specifically what 00:01:38.840 --> 00:01:41.859 that crest was actually doing, it stops being 00:01:41.859 --> 00:01:44.280 a generic duck bill and becomes something much, 00:01:44.299 --> 00:01:46.579 much stranger. It really does. The engineering 00:01:46.579 --> 00:01:49.040 involved in this animal's skull alone is enough 00:01:49.040 --> 00:01:50.879 to keep us busy for the next hour. I mean, we 00:01:50.879 --> 00:01:52.700 aren't just looking at bones today. We are looking 00:01:52.700 --> 00:01:55.530 at... acoustics, thermodynamics, social behavior, 00:01:55.829 --> 00:01:58.010 the whole package. Okay, before we get into the 00:01:58.010 --> 00:01:59.549 really heavy engineering, let's just get the 00:01:59.549 --> 00:02:04.230 taxonomy out of the way. Parasaurolophus. It's 00:02:04.230 --> 00:02:06.840 a mouthful. I feel like I have to take a breath 00:02:06.840 --> 00:02:09.020 before saying it. It is a bit of a tongue twister. 00:02:09.060 --> 00:02:10.500 What are we actually saying when we say that 00:02:10.500 --> 00:02:13.379 name? Well, it translates literally to beside 00:02:13.379 --> 00:02:16.419 crested lizard. Beside crested lizard. That sounds 00:02:16.419 --> 00:02:19.460 odd. It does, but you have to understand the 00:02:19.460 --> 00:02:21.900 context of the discovery. We're going all the 00:02:21.900 --> 00:02:25.780 way back to 1922. William Parks, the paleontologist 00:02:25.780 --> 00:02:28.419 describing it, was looking at this new fossil 00:02:28.419 --> 00:02:31.039 found in Alberta, and he's looking at the skull 00:02:31.039 --> 00:02:33.520 and thinking, well, this looks a lot like another 00:02:33.520 --> 00:02:35.860 dinosaur I know called Saurolophus. Saurolophus, 00:02:35.939 --> 00:02:39.469 which means? crested lizard. Oh, okay. That makes 00:02:39.469 --> 00:02:42.710 sense. Exactly. Saurolophus had a solid, much 00:02:42.710 --> 00:02:45.870 smaller crest. So Parks, being a practical scientist, 00:02:46.150 --> 00:02:49.650 basically names this new one near or beside Saurolophus. 00:02:49.750 --> 00:02:51.909 It's not the most poetic name I'll grant you, 00:02:51.949 --> 00:02:53.629 but it tells you exactly where it sits on the 00:02:53.629 --> 00:02:56.530 family tree. So it's basically the crested lizard's 00:02:56.530 --> 00:02:59.169 neighbor. Pretty much. And taxonomically, we 00:02:59.169 --> 00:03:02.469 are placing this animal in the family Hedrosauridae. 00:03:02.789 --> 00:03:05.789 These are the duck -billed dinosaurs. But within 00:03:05.789 --> 00:03:08.110 that family, there's a crucial split you need 00:03:08.110 --> 00:03:11.389 to know to understand the deep dive today. You 00:03:11.389 --> 00:03:14.110 have the Hadrosaurines, which generally have 00:03:14.110 --> 00:03:17.370 flat heads or solid crests. Think Edmontosaurus 00:03:17.370 --> 00:03:20.189 or Myasaura. And then you have the Lambiosaurines. 00:03:20.780 --> 00:03:23.439 And our guy is a Lambia serene. Exclusively. 00:03:23.439 --> 00:03:27.060 The Lambia serenes are the hollow -crested duckbills. 00:03:27.379 --> 00:03:30.219 And that word hollow, that is the key. That's 00:03:30.219 --> 00:03:31.780 the big distinction. That is the distinction 00:03:31.780 --> 00:03:34.060 that drives almost all the biology we're going 00:03:34.060 --> 00:03:35.819 to talk about. If you don't have that hollow 00:03:35.819 --> 00:03:38.319 space, you're just a flat -headed grazer. If 00:03:38.319 --> 00:03:40.900 you do have it, well, you're capable of some 00:03:40.900 --> 00:03:43.139 pretty incredible physics. Okay, hold that thought 00:03:43.139 --> 00:03:44.919 on the physics. I want to ground this in physical 00:03:44.919 --> 00:03:48.460 reality first. Because duckbill dinosaur sounds 00:03:48.460 --> 00:03:51.550 cute. It sounds manageable. It does. Like a big 00:03:51.550 --> 00:03:53.509 mallard that you could maybe feed bread to at 00:03:53.509 --> 00:03:55.669 the park. Please do not try to feed bread to 00:03:55.669 --> 00:03:58.750 a Parasaurolophus. Why not? Help us visualize 00:03:58.750 --> 00:04:01.349 this scale here. If I'm standing next to a fully 00:04:01.349 --> 00:04:04.990 grown Parasaurolophus walkery, that's the classic 00:04:04.990 --> 00:04:07.169 species, right? That's the type Cepheusia. What 00:04:07.169 --> 00:04:09.210 am I looking at? What am I feeling? You are looking 00:04:09.210 --> 00:04:12.189 at a wall of muscle. You would feel incredibly 00:04:12.189 --> 00:04:15.060 insignificant. We are talking about an animal 00:04:15.060 --> 00:04:19.180 that is roughly 9 .45 meters long. That's 31 00:04:19.180 --> 00:04:22.939 feet. 31 feet. So imagine a standard yellow school 00:04:22.939 --> 00:04:25.139 bus parked in front of you. Now imagine that 00:04:25.139 --> 00:04:28.620 school bus has legs and can run. That's substantial. 00:04:29.160 --> 00:04:31.399 That's a lot bigger than I pictured. It is. And 00:04:31.399 --> 00:04:33.680 it's not just the length. It's the mass. The 00:04:33.680 --> 00:04:37.430 weight estimates. Well, they vary a bit depending 00:04:37.430 --> 00:04:39.470 on the method you use. How do they even figure 00:04:39.470 --> 00:04:41.350 that out? Is it just a guess? It's more than 00:04:41.350 --> 00:04:43.850 a guess. You can do volumetric models where you 00:04:43.850 --> 00:04:46.970 sort of shrink wrap a digital skeleton with muscle 00:04:46.970 --> 00:04:49.529 and calculate the volume. Or you can use the 00:04:49.529 --> 00:04:51.370 circumference of the leg bones and compare it 00:04:51.370 --> 00:04:53.970 to living animals. Okay. So what are those models 00:04:53.970 --> 00:04:56.709 telling us? They're consistently landing us between 00:04:56.709 --> 00:05:00.149 2 .5 and 5 metric tons. So that upper limit is 00:05:00.149 --> 00:05:02.750 about 5 .5 short tons. So we're talking African 00:05:02.750 --> 00:05:05.819 elephant territory. Easily. Maybe even heavier 00:05:05.819 --> 00:05:08.160 than an average elephant. And unlike an elephant, 00:05:08.240 --> 00:05:09.980 which is, you know, four on the floor stable, 00:05:10.319 --> 00:05:13.439 this animal is built very differently. It's carrying 00:05:13.439 --> 00:05:15.779 that mass in a completely different way. Right. 00:05:15.860 --> 00:05:18.379 Which brings us to the locomotion question. Because 00:05:18.379 --> 00:05:20.800 I've seen artwork of them walking on four legs, 00:05:20.879 --> 00:05:23.040 looking all peaceful. And then I've seen artwork 00:05:23.040 --> 00:05:25.360 of them running on two legs, looking absolutely 00:05:25.360 --> 00:05:28.240 terrifying. Which one is it? They're both right. 00:05:28.540 --> 00:05:31.910 We call this being a facultative biped. Okay, 00:05:31.949 --> 00:05:34.129 define that for us. It essentially means the 00:05:34.129 --> 00:05:36.910 animal has a choice. It's not locked into one 00:05:36.910 --> 00:05:39.889 way of moving. Most of the time, when it's just 00:05:39.889 --> 00:05:42.649 grazing, conserving energy, moving slowly through 00:05:42.649 --> 00:05:45.370 the brush, it's a quadruped. It's on all fours. 00:05:45.389 --> 00:05:47.370 That makes sense. It's the most efficient way 00:05:47.370 --> 00:05:49.769 to support that five -ton gut. Exactly. It's 00:05:49.769 --> 00:05:52.709 engaging the front drive, so to speak. But... 00:05:52.939 --> 00:05:55.220 If a predator, say, a Gorgosaurus, appears on 00:05:55.220 --> 00:05:57.100 the horizon or it needs to cover ground quickly, 00:05:57.339 --> 00:06:00.019 it can shift its weight back, lift those front 00:06:00.019 --> 00:06:02.399 arms up, and sprint on its hind legs. A five 00:06:02.399 --> 00:06:05.660 -ton animal sprinting on two legs is... That's 00:06:05.660 --> 00:06:07.839 a terrifying image. That's a lot of kinetic energy 00:06:07.839 --> 00:06:11.160 moving very, very fast. It is. And the skeleton... 00:06:11.579 --> 00:06:14.860 absolutely supports this power. If you look at 00:06:14.860 --> 00:06:17.259 the femur, the thigh bone of Peawalkery, it's 00:06:17.259 --> 00:06:20.839 over a meter long, about 103 centimeters. It 00:06:20.839 --> 00:06:23.920 is an incredibly robust, thick piece of bone. 00:06:24.019 --> 00:06:27.259 Wow. And the pelvis is just... massive, heavily 00:06:27.259 --> 00:06:31.300 built to anchor these huge running muscles. But 00:06:31.300 --> 00:06:33.379 then you look at the arms, the humerus, and they 00:06:33.379 --> 00:06:35.920 are relatively short, especially for a hadrosaur 00:06:35.920 --> 00:06:38.040 of that size. So they're a little bit T -Rex 00:06:38.040 --> 00:06:40.639 -y in that way. Big legs, smaller arms. A little 00:06:40.639 --> 00:06:42.740 bit, yeah. They're definitely not as comically 00:06:42.740 --> 00:06:45.040 small as a T -Rex is, but the power is all in 00:06:45.040 --> 00:06:47.019 the back. They wouldn't be winning marathons 00:06:47.019 --> 00:06:50.000 on two legs, but for a short, powerful burst 00:06:50.000 --> 00:06:52.139 of speed, they were built for it. And while we're 00:06:52.139 --> 00:06:53.740 on the body, you mentioned something in the notes 00:06:53.740 --> 00:06:57.189 about the spine. They had a weird back. Not weird, 00:06:57.209 --> 00:06:59.569 so much as distinct. They had these very tall, 00:06:59.769 --> 00:07:02.189 neural spines sticking up from the vertebrae, 00:07:02.189 --> 00:07:03.870 especially over the hips and the back. So it 00:07:03.870 --> 00:07:06.170 wasn't a flat back like a lizard? No, not at 00:07:06.170 --> 00:07:08.490 all. It gave it a high -backed look, almost like 00:07:08.490 --> 00:07:11.110 a ridge running down the spine. It created a 00:07:11.110 --> 00:07:13.410 very distinct profile, even before you get to 00:07:13.410 --> 00:07:15.430 the head crest. Okay, let's get to the head. 00:07:15.550 --> 00:07:17.170 I want to circle back to the duck bill part. 00:07:17.389 --> 00:07:19.350 You mentioned earlier that calling it a duck 00:07:19.350 --> 00:07:22.149 is a problem. But, I mean, it has a bill. I'm 00:07:22.149 --> 00:07:23.449 looking at the skull right now in the notes. 00:07:23.569 --> 00:07:27.000 It has this... broad, flat beak. It has a beak, 00:07:27.139 --> 00:07:30.220 yes. But the function is totally, totally different. 00:07:30.420 --> 00:07:33.120 A duck uses its bill to, you know, dabble in 00:07:33.120 --> 00:07:35.540 the water, filtering out soft algae and little 00:07:35.540 --> 00:07:38.060 bugs. Right. It doesn't chew. It just sort of 00:07:38.060 --> 00:07:40.879 slurps. Parasaurolophus was a shooing machine, 00:07:41.060 --> 00:07:43.959 an industrial -grade shooing machine. But reptiles 00:07:43.959 --> 00:07:46.610 don't chew. That's like the rule, right? They 00:07:46.610 --> 00:07:48.990 rip and swallow. Crocodiles don't chew. Lizards 00:07:48.990 --> 00:07:51.730 don't chew. Usually, yes, that is the rule. But 00:07:51.730 --> 00:07:54.170 hadrosaurs, they invented a way to cheat the 00:07:54.170 --> 00:07:56.389 system. They evolved something that we mammals 00:07:56.389 --> 00:07:58.930 usually claim is our own special invention. Behind 00:07:58.930 --> 00:08:01.110 that beak, they had what we call dental batteries. 00:08:01.529 --> 00:08:04.589 Batteries, like are they energized? No, no, not 00:08:04.589 --> 00:08:06.889 electric. Think more like an artillery battery. 00:08:07.170 --> 00:08:09.790 Rows and rows of guns. Oh, I see. So imagine 00:08:09.790 --> 00:08:13.079 a dense pavement of teeth. Hundreds of small 00:08:13.079 --> 00:08:15.860 diamond -shaped teeth packed tightly together 00:08:15.860 --> 00:08:19.259 in these columns. As the animal ground down tough 00:08:19.259 --> 00:08:22.019 vegetation, we're talking pine needles, twigs, 00:08:22.120 --> 00:08:24.779 abrasive ferns, the surface teeth would wear 00:08:24.779 --> 00:08:27.100 away. And then they'd be toothless. Nope. Immediately 00:08:27.100 --> 00:08:29.500 underneath, there was another tooth ready to 00:08:29.500 --> 00:08:31.759 push up and replace it. It was a constant conveyor 00:08:31.759 --> 00:08:34.340 belt of new grinding surfaces. Like a shark's 00:08:34.340 --> 00:08:36.679 mouth, but for grinding. Similar concept, yeah, 00:08:36.720 --> 00:08:39.399 but arranged for grinding, not for slicing. A 00:08:39.399 --> 00:08:42.240 shark slices. A hadros... sore grinds. And the 00:08:42.240 --> 00:08:44.419 mechanics of the jaw itself are just fascinating. 00:08:44.580 --> 00:08:47.460 We call it pleurokinesis. Pleurokinesis. Okay, 00:08:47.519 --> 00:08:49.580 break that down for us. Pleuro meaning side, 00:08:49.820 --> 00:08:52.480 kinesis meaning movement. So when a cow chews, 00:08:52.480 --> 00:08:55.220 it moves its lower jaw side to side. You've seen 00:08:55.220 --> 00:08:57.700 a cow chewing its cud. Sure. That round grinding 00:08:57.700 --> 00:09:00.440 motion. Right. A Parasaurolophus couldn't move 00:09:00.440 --> 00:09:02.740 its jaw side to side quite like that. Instead, 00:09:03.080 --> 00:09:05.799 the upper jaw bones, the maxillae, could actually 00:09:05.799 --> 00:09:08.399 flex and rotate slightly outwards against the 00:09:08.399 --> 00:09:11.179 lower jaw. The skull itself was flexible. The 00:09:11.179 --> 00:09:14.490 whole skull moved. Parts of it, yes. It created 00:09:14.490 --> 00:09:18.029 this incredibly effective grinding surface that 00:09:18.029 --> 00:09:21.190 could pulverize the toughest plants in the Cretaceous. 00:09:21.549 --> 00:09:24.629 This wasn't passive eating. This was industrial 00:09:24.629 --> 00:09:27.149 processing. That makes so much sense. You don't 00:09:27.149 --> 00:09:29.330 get to be five tons by just nibbling on soft 00:09:29.330 --> 00:09:32.149 algae. You need a massive calorie intake. You 00:09:32.149 --> 00:09:34.710 need to unlock the nutrients in wood and tough 00:09:34.710 --> 00:09:37.149 leaves. Exactly. They were effectively giant 00:09:37.149 --> 00:09:39.990 biological wood chippers. We should mention the 00:09:39.990 --> 00:09:41.929 skin, too. I saw a note that we actually have 00:09:41.929 --> 00:09:44.509 impressions. We do. is incredibly rare. They 00:09:44.509 --> 00:09:47.649 show these uniform tubercle -like scales, like 00:09:47.649 --> 00:09:50.889 little bumps, but no larger distinct structures 00:09:50.889 --> 00:09:53.470 like scutes or armor, just this pebbly texture 00:09:53.470 --> 00:09:56.230 all over. Okay, so we have a five -ton bipedal 00:09:56.230 --> 00:09:58.590 sprinting industrial chewing pebbly skin machine, 00:09:58.789 --> 00:10:01.110 but we haven't talked about the elephant in the 00:10:01.110 --> 00:10:03.470 room, or rather the trombone in the room. The 00:10:03.470 --> 00:10:05.350 crest. The crest. This is what I was looking 00:10:05.350 --> 00:10:07.659 forward to, the great crest debate. I was reading 00:10:07.659 --> 00:10:09.440 through the history of how scientists have interpreted 00:10:09.440 --> 00:10:11.220 this thing, and it feels like a comedy of errors. 00:10:11.580 --> 00:10:13.580 It's like for 50 years, everyone has projected 00:10:13.580 --> 00:10:16.059 their own weird theories onto this bone tube. 00:10:16.429 --> 00:10:18.809 You have to be a little fair to the early paleontologists. 00:10:19.110 --> 00:10:21.690 They were working without CT scanners, without 00:10:21.690 --> 00:10:24.250 soft tissue evidence, and often with really incomplete 00:10:24.250 --> 00:10:27.690 skeletons. They saw a shape and tried to find 00:10:27.690 --> 00:10:30.129 an analogy in nature, and the biggest bias they 00:10:30.129 --> 00:10:32.970 had was the habitat. The swamp bias. Right. The 00:10:32.970 --> 00:10:35.710 prevailing dogma in the early 1900s was that 00:10:35.710 --> 00:10:38.009 these big dinosaurs were just too heavy for land. 00:10:38.149 --> 00:10:39.909 They thought their legs would snap under their 00:10:39.909 --> 00:10:42.750 own weight. So they had to be aquatic. They had 00:10:42.750 --> 00:10:45.710 to live in swamps to let the water support them. 00:10:45.710 --> 00:10:48.309 their massive bulk. Which we now know is completely 00:10:48.309 --> 00:10:51.590 wrong. Completely. But it colored every interpretation. 00:10:52.009 --> 00:10:55.490 So when Alfred Sherwood Romer looks at Parasaurolophus 00:10:55.490 --> 00:10:58.250 in that context, he sees a creature living in 00:10:58.250 --> 00:11:00.169 the water. And what do you need if you're underwater? 00:11:00.509 --> 00:11:03.409 A snorkel. A snorkel. So Romer proposes quite 00:11:03.409 --> 00:11:06.029 seriously that the crest is literally a breathing 00:11:06.029 --> 00:11:08.409 tube. I mean, visually, it works perfectly. You 00:11:08.409 --> 00:11:10.710 can just picture the dinosaur submerged, just 00:11:10.710 --> 00:11:13.049 the tip of that crest poking out of the water 00:11:13.049 --> 00:11:15.399 like a periscope. This is a very... stealthy, 00:11:15.399 --> 00:11:17.820 cool image. A great image. It would make a great 00:11:17.820 --> 00:11:21.259 movie monster. But anatomically, it's a complete 00:11:21.259 --> 00:11:25.320 and total disaster. Why? What's the fatal flaw? 00:11:25.580 --> 00:11:27.720 Well, the fatal flaw is that there's no hole 00:11:27.720 --> 00:11:30.759 at the end. It's solid bone at the tip. The airway 00:11:30.759 --> 00:11:32.759 starts at the nose, goes all the way up the crest, 00:11:32.980 --> 00:11:35.100 does a U -turn at the top, comes all the way 00:11:35.100 --> 00:11:37.769 back down, and then goes into the throat. It's 00:11:37.769 --> 00:11:40.110 a closed loop. It's a closed loop. If you used 00:11:40.110 --> 00:11:42.429 it as a snorkel, you'd just be sticking a sealed 00:11:42.429 --> 00:11:44.549 tube out of the water. You'd suffocate immediately. 00:11:44.690 --> 00:11:47.210 It fails at the most basic level. Okay, so the 00:11:47.210 --> 00:11:49.889 snorkel is dead on arrival. But they didn't give 00:11:49.889 --> 00:11:52.250 up on the water angle, did they? The bias was 00:11:52.250 --> 00:11:55.230 strong. No, it was very, very strong. So then 00:11:55.230 --> 00:11:58.610 came the air trap theory. Charles Sternberg and 00:11:58.610 --> 00:12:01.289 later Ned Colbert thought, okay, okay, maybe 00:12:01.289 --> 00:12:03.769 it's not a snorkel. Maybe it's a scuba tank. 00:12:03.909 --> 00:12:06.629 An air reservoir to hold their breath. Exactly. 00:12:06.769 --> 00:12:09.250 The idea was they could fill this hollow crest 00:12:09.250 --> 00:12:11.909 with air and use to hold their breath for long 00:12:11.909 --> 00:12:14.769 periods underwater, like soaring extra oxygen 00:12:14.769 --> 00:12:17.330 for a deep dive to escape a predator. That sounds 00:12:17.330 --> 00:12:20.269 a little more plausible. I mean, whales hold 00:12:20.269 --> 00:12:23.149 their breath. It sounds plausible until you do 00:12:23.149 --> 00:12:25.570 the math. We're talking about a multi -ton animal 00:12:25.570 --> 00:12:27.929 with lungs probably the size of a refrigerator. 00:12:28.429 --> 00:12:33.799 The volume of air inside that crest is... maybe 00:12:33.799 --> 00:12:36.980 at best a couple of liters. It's a tiny, tiny 00:12:36.980 --> 00:12:39.659 fraction of their total lung capacity. So that's 00:12:39.659 --> 00:12:41.899 like a human trying to survive underwater by 00:12:41.899 --> 00:12:43.860 holding an extra mouthful of air in their cheeks. 00:12:43.980 --> 00:12:45.919 That is a perfect analogy. It would buy them 00:12:45.919 --> 00:12:48.409 maybe three seconds of extra dive time. From 00:12:48.409 --> 00:12:51.429 an evolutionary standpoint, it is way too expensive 00:12:51.429 --> 00:12:54.190 an investment. Growing this massive, complex 00:12:54.190 --> 00:12:56.909 bone structure just for three extra seconds of 00:12:56.909 --> 00:12:58.850 air. It doesn't pay off. So it fails the cost 00:12:58.850 --> 00:13:00.850 -benefit analysis. Deserpsly. All right, so they're 00:13:00.850 --> 00:13:03.070 out of the water. What happens next? We get into 00:13:03.070 --> 00:13:05.450 the weapon theories, right? Athenio Abel suggested 00:13:05.450 --> 00:13:07.990 it was a club. A battering ram, yeah. The idea 00:13:07.990 --> 00:13:10.250 was that males would spar, head -butting each 00:13:10.250 --> 00:13:12.470 other like bighorn sheep, either for mates or 00:13:12.470 --> 00:13:14.889 for territory. But again, looking at the anatomy, 00:13:15.149 --> 00:13:19.059 that just doesn't seem right. bone it's hollow 00:13:19.059 --> 00:13:22.240 it's thin the walls the crest are actually quite 00:13:22.240 --> 00:13:25.879 fragile if you took a five ton run and smashed 00:13:25.879 --> 00:13:28.720 that crest into a rival's ribs you wouldn't break 00:13:28.720 --> 00:13:31.059 their ribs you would shatter your own face it 00:13:31.059 --> 00:13:33.799 would be a catastrophic self -injury the sinuses 00:13:33.799 --> 00:13:36.259 would collapse it's just not built for impact 00:13:36.259 --> 00:13:38.700 it's delicate my absolute favorite though has 00:13:38.700 --> 00:13:40.990 to be the proboscis theory This one feels like 00:13:40.990 --> 00:13:43.230 it came from a fever dream. Oh, Martin Woolforth. 00:13:43.370 --> 00:13:46.590 Yes, the trunk. Tell us about the trunk. It's 00:13:46.590 --> 00:13:49.230 just so wonderfully bizarre. So Woolforth looked 00:13:49.230 --> 00:13:51.250 at the crest and thought, what if this isn't 00:13:51.250 --> 00:13:53.649 just a crest? What if it's an attachment point 00:13:53.649 --> 00:13:56.809 for big muscles? And he proposed that a mobile 00:13:56.809 --> 00:13:59.429 trunk, like an elephant's, dangled off the end 00:13:59.429 --> 00:14:01.629 of the crest to grab leaves and pull them to 00:14:01.629 --> 00:14:04.600 the mouth. I am trying so hard to picture a duck 00:14:04.600 --> 00:14:07.159 -billed dinosaur with an elephant trunk coming 00:14:07.159 --> 00:14:09.399 out of its forehead. It's a nightmare. It looks 00:14:09.399 --> 00:14:11.960 like something from a bad 1950s sci -fi movie. 00:14:12.080 --> 00:14:14.399 It's strictly impossible. Elephants have these 00:14:14.399 --> 00:14:16.899 massive, rough scars on their skulls where those 00:14:16.899 --> 00:14:19.360 powerful trunk muscles attach. You can see exactly 00:14:19.360 --> 00:14:21.580 where the anchor points are. And Parasaurolophus. 00:14:21.899 --> 00:14:25.659 Nothing. The bone is smooth. There are no muscle 00:14:25.659 --> 00:14:29.460 scars. Plus, as we just established, it has a 00:14:29.460 --> 00:14:32.799 hyper -efficient beak and grinding teeth. Why 00:14:32.799 --> 00:14:35.340 would you evolve a cropping beak and a trunk 00:14:35.340 --> 00:14:38.059 to do the exact same job? It's redundant. Completely. 00:14:38.539 --> 00:14:40.980 Nature almost never keeps two expensive tools 00:14:40.980 --> 00:14:42.879 that do the same thing. Okay, there's one more 00:14:42.879 --> 00:14:44.740 that was kind of funny. The foliage deflector. 00:14:44.860 --> 00:14:47.600 Andrew Milner's idea. Right. That it worked like 00:14:47.600 --> 00:14:50.919 a helmet or the cask on a cassowary, you know, 00:14:50.919 --> 00:14:53.539 pushing branches and leaves out of the way as 00:14:53.539 --> 00:14:55.100 it ran through the forest. Which makes sense 00:14:55.100 --> 00:14:56.879 for the shape, right? It sweeps back. It looks 00:14:56.879 --> 00:14:58.620 like it could part the bushes. The shape works. 00:14:58.740 --> 00:15:01.299 Sure, I'll give him that. But it doesn't explain 00:15:01.299 --> 00:15:03.779 the inside. If it's just a branch of asher, why 00:15:03.779 --> 00:15:05.980 is it hollow? Why does it have all these complex 00:15:05.980 --> 00:15:08.960 internal tubes and chambers? You could just have 00:15:08.960 --> 00:15:12.559 a solid ridge of bone. The complexity. The complexity 00:15:12.559 --> 00:15:16.240 implies a more sophisticated function. It's over 00:15:16.240 --> 00:15:19.200 -engineered for just pushing leaves. So we've 00:15:19.200 --> 00:15:22.980 ruled out snorkel, scuba tank, club, trunk, and 00:15:22.980 --> 00:15:26.159 helmet. Which is a pretty good list of what it 00:15:26.159 --> 00:15:28.460 wasn't. Yeah. That leaves us with the theory 00:15:28.460 --> 00:15:31.049 that actually stuck. And this is where the story 00:15:31.049 --> 00:15:34.070 gets really, really cool because we stop guessing 00:15:34.070 --> 00:15:38.990 and start using physics. The idea that the crest 00:15:38.990 --> 00:15:41.970 is fundamentally a musical instrument. A biological 00:15:41.970 --> 00:15:44.240 resonator. This is the leading theory today, 00:15:44.360 --> 00:15:47.259 by a wide margin. And we have hard data on this. 00:15:47.360 --> 00:15:51.279 In 1997, a team at Sandia National Laboratories, 00:15:51.379 --> 00:15:53.379 and you have to keep in mind, these are people 00:15:53.379 --> 00:15:55.840 who usually model shockwaves for nuclear explosions 00:15:55.840 --> 00:15:58.039 or high -speed aerodynamics for jets. Right, 00:15:58.080 --> 00:15:59.940 they're not paleontologists. Not at all. They 00:15:59.940 --> 00:16:01.820 got involved in this project. That's a crossover 00:16:01.820 --> 00:16:04.299 I did not expect. They got their hands on a CT 00:16:04.299 --> 00:16:08.440 scan of a Parasaurolophus tubicin skull. Tubicin? 00:16:08.480 --> 00:16:10.779 That's the one with the most complex crest. Correct. 00:16:10.980 --> 00:16:13.379 Tubicin literally means trumpeter. Its crest 00:16:13.379 --> 00:16:16.179 is longer and has a more intricate internal structure 00:16:16.179 --> 00:16:18.639 than the other species. So they took that digital 00:16:18.639 --> 00:16:20.580 model and they simulated airflow through it. 00:16:20.580 --> 00:16:22.580 They basically played the dinosaur like a virtual 00:16:22.580 --> 00:16:25.240 instrument to see what sound it would make. And 00:16:25.240 --> 00:16:27.399 what happened? What did it sound like? The crest 00:16:27.399 --> 00:16:30.539 acted as a perfect resonance chamber. The air 00:16:30.539 --> 00:16:33.279 travels from the nostrils up the long tubes, 00:16:33.360 --> 00:16:36.480 vibrates, and produces a sound. But not just 00:16:36.480 --> 00:16:39.299 any sound. Because the tube is so long, over 00:16:39.299 --> 00:16:42.779 two meters in some adults, it resonates at incredibly 00:16:42.779 --> 00:16:45.320 low frequencies. How low are we talking? The 00:16:45.320 --> 00:16:47.620 fundamental frequency that's the lowest note 00:16:47.620 --> 00:16:50.799 it could produce was about 30 hertz. 30 hertz. 00:16:51.639 --> 00:16:53.899 For context, the lowest note on a standard 88 00:16:53.899 --> 00:16:58.200 key piano is about 27 hertz. So this is deep. 00:16:58.480 --> 00:17:00.559 This is bass. It's right at the bottom edge of 00:17:00.559 --> 00:17:02.820 human hearing. We can generally hear down to 00:17:02.820 --> 00:17:05.079 about 20 hertz. So if you were standing there 00:17:05.079 --> 00:17:06.660 on the Cretaceous, you wouldn't just hear this 00:17:06.660 --> 00:17:08.720 sound, you would feel it. Like when a subwoofer 00:17:08.720 --> 00:17:10.599 hits in a movie theater. That rumble in your 00:17:10.599 --> 00:17:13.240 chest. Exactly that. A visceral thrumming that 00:17:13.240 --> 00:17:15.599 you feel in your bones. The modeling suggested 00:17:15.599 --> 00:17:17.960 they could produce a whole range of sounds from 00:17:17.960 --> 00:17:21.359 about 55 to 720 hertz. But that low end rumble 00:17:21.359 --> 00:17:23.779 is the key. Why is the low end the key? Why not 00:17:23.779 --> 00:17:26.500 just chirp like a bird? Why invest so much bone 00:17:26.500 --> 00:17:29.539 and energy in being a biological subwoofer? Physics 00:17:29.539 --> 00:17:32.579 again. High -frequency sounds, chirps, squeaks, 00:17:32.599 --> 00:17:35.940 whistles, they scatter easily. Leaves, trees, 00:17:36.200 --> 00:17:38.980 even fog, they all block and absorb high -frequency 00:17:38.980 --> 00:17:42.019 sound waves. If you yell in a dense forest, your 00:17:42.019 --> 00:17:44.420 voice doesn't travel very far. Right. But low 00:17:44.420 --> 00:17:47.039 -frequency infrasound, it cuts through everything, 00:17:47.220 --> 00:17:50.559 it travels for miles, barely losing any energy. 00:17:50.799 --> 00:17:53.450 Like elephants. I know they use infrasound. Exactly 00:17:53.450 --> 00:17:55.869 like elephants. Elephants use infrasound to coordinate 00:17:55.869 --> 00:17:59.369 herd movements over vast distances. You might 00:17:59.369 --> 00:18:01.089 not be able to hear an elephant calling from 00:18:01.089 --> 00:18:03.230 two miles away, but another elephant certainly 00:18:03.230 --> 00:18:06.150 does. Parasaurolophus was likely doing the exact 00:18:06.150 --> 00:18:08.029 same thing. They were broadcasting. What were 00:18:08.029 --> 00:18:10.410 they saying? I'm here. Predator approaching. 00:18:10.710 --> 00:18:12.809 Where is the herd? This is good feeding ground. 00:18:13.049 --> 00:18:15.450 Long -distance communication to keep a potentially 00:18:15.450 --> 00:18:18.789 huge scattered group cohesive. And the biology 00:18:18.789 --> 00:18:21.130 backs this up, right? It's not just the crest. 00:18:21.680 --> 00:18:23.920 You need the right hardware to hear what you're 00:18:23.920 --> 00:18:26.660 shouting. Right. It's pointless to make a specific 00:18:26.660 --> 00:18:29.099 sound if no one can hear it. And when we've looked 00:18:29.099 --> 00:18:32.299 at the brain cases of hadrosaurs, we find that 00:18:32.299 --> 00:18:34.380 they had very delicate stapes, those little ear 00:18:34.380 --> 00:18:37.720 bones, and an elongated cochlear duct, which 00:18:37.720 --> 00:18:40.019 is very similar to what you see in a modern crocodile. 00:18:40.359 --> 00:18:42.990 And that means... That setup is specifically 00:18:42.990 --> 00:18:45.630 tuned to be highly sensitive to low frequencies. 00:18:45.990 --> 00:18:48.750 So they had the transmitter, the crest, and they 00:18:48.750 --> 00:18:51.630 had the receiver, the ears. It's a complete system. 00:18:51.849 --> 00:18:54.329 That completely recontextualizes the whole animal. 00:18:54.490 --> 00:18:57.890 It's not a silent, peaceful grazer. It's a node 00:18:57.890 --> 00:19:00.470 in a communication network. A very loud one. 00:19:00.490 --> 00:19:02.569 Imagine a whole herd of these things. It wouldn't 00:19:02.569 --> 00:19:04.829 have been a quiet, peaceful swamp. It would have 00:19:04.829 --> 00:19:06.650 been a constant thrumming conversation happening 00:19:06.650 --> 00:19:09.049 all around you. But the crest wasn't just for 00:19:09.049 --> 00:19:12.089 sound, surely. If you stick a six -foot tube 00:19:12.089 --> 00:19:13.890 on your head, people are going to look at it. 00:19:13.910 --> 00:19:16.180 There has to be a visual component. Oh, absolutely. 00:19:16.480 --> 00:19:18.960 We can't ignore the visual aspect. Dinosaurs 00:19:18.960 --> 00:19:21.799 were highly visual animals. We know from their 00:19:21.799 --> 00:19:24.059 skulls that they had large optic lobes in their 00:19:24.059 --> 00:19:26.980 brains and large sclerotic rings in their eyes. 00:19:27.160 --> 00:19:29.819 Sclerotic rings. They're rings of bone that support 00:19:29.819 --> 00:19:32.299 the eyeball. Their size tells us about the size 00:19:32.299 --> 00:19:35.380 of the eye and likely their reliance on vision. 00:19:35.720 --> 00:19:38.339 Everything points to them having excellent daytime 00:19:38.339 --> 00:19:40.920 vision, probably in color. So the crest is a 00:19:40.920 --> 00:19:44.640 flag, a billboard. It's a species ID card. You 00:19:44.640 --> 00:19:46.579 have to remember Parasaurolophus didn't live 00:19:46.579 --> 00:19:49.319 alone. It lived alongside other Lambiosaurians 00:19:49.319 --> 00:19:51.839 like Korthosaurus and Lambiosaurus, which also 00:19:51.839 --> 00:19:54.819 had these big hollow crests, but they were shaped 00:19:54.819 --> 00:19:57.500 differently, like helmets or hatchets. If you're 00:19:57.500 --> 00:19:59.980 a Parasaurolophus looking for a mate from a mile 00:19:59.980 --> 00:20:02.180 away, you need to be able to spot that unique, 00:20:02.339 --> 00:20:05.779 long, curved profile instantly. You don't want 00:20:05.779 --> 00:20:07.660 to waste time and energy courting a Korthosaurus. 00:20:07.900 --> 00:20:09.740 And presumably, the bigger the crest, the better 00:20:09.740 --> 00:20:12.190 the mate. The classic sexual selection. argument 00:20:12.190 --> 00:20:14.690 that's the standard theory and it holds up well 00:20:14.690 --> 00:20:17.930 here a big elaborate crest is expensive to grow 00:20:17.930 --> 00:20:20.170 it takes a lot of calcium a lot of energy and 00:20:20.170 --> 00:20:23.490 a lot of time if you have a massive perfect crest 00:20:23.490 --> 00:20:26.529 you are advertising to the opposite sex look 00:20:26.529 --> 00:20:29.089 at my good genes i am so healthy and successful 00:20:29.089 --> 00:20:31.430 that i can waste energy on this giant ridiculous 00:20:31.430 --> 00:20:33.890 hat meet with me so it's a dual purpose signal 00:20:33.890 --> 00:20:37.130 the shape tells you the species and the size 00:20:37.130 --> 00:20:39.190 and quality tell you about the fitness of the 00:20:39.190 --> 00:20:41.579 individual exactly And the sound would have been 00:20:41.579 --> 00:20:44.019 part of that, too. A bigger crest would produce 00:20:44.019 --> 00:20:46.859 a deeper, more resonant call. So you could see 00:20:46.859 --> 00:20:49.440 and hear the quality of a potential mate from 00:20:49.440 --> 00:20:51.920 a long way off. Before we move on, I want to 00:20:51.920 --> 00:20:54.359 touch on one other functional theory that seems 00:20:54.359 --> 00:20:56.920 to have some merit, even if it's not the primary 00:20:56.920 --> 00:21:00.900 one. The air conditioning theory. Ah, yes. Wheeler's 00:21:00.900 --> 00:21:03.579 theory from 1978. This one is really interesting 00:21:03.579 --> 00:21:06.240 because it deals with thermodynamics. The idea 00:21:06.240 --> 00:21:08.420 is that because the crest has so much surface 00:21:08.420 --> 00:21:11.240 area and the bone is vascularized, which means 00:21:11.240 --> 00:21:13.559 it had lots of blood vessels, it worked like 00:21:13.559 --> 00:21:16.319 a radiator to cool the brain. Right. The basic 00:21:16.319 --> 00:21:19.240 concept is you pump hot blood from the body up 00:21:19.240 --> 00:21:21.619 into the crest. At the same time, you're breathing 00:21:21.619 --> 00:21:24.920 in cooler air through your nose. That air moves 00:21:24.920 --> 00:21:27.099 through all those internal tubes and passages, 00:21:27.359 --> 00:21:29.859 cooling the blood through convection. And then 00:21:29.859 --> 00:21:32.920 that newly cooled blood flows back down and circulates 00:21:32.920 --> 00:21:34.920 around the brain, keeping it from overheating. 00:21:35.000 --> 00:21:36.759 It's a biological brain cooler. Does that hold 00:21:36.759 --> 00:21:39.700 up? It's very likely a secondary benefit. I don't 00:21:39.700 --> 00:21:41.759 think most paleontologists think the crest evolved 00:21:41.759 --> 00:21:44.930 for that purpose. Why not? Well... You could 00:21:44.930 --> 00:21:47.109 cool down with much simpler structures like the 00:21:47.109 --> 00:21:50.210 big ears on an elephant or the frill on a triceratops. 00:21:50.609 --> 00:21:53.750 You don't need to evolve a complex, sound -producing 00:21:53.750 --> 00:21:56.730 trombone just to cool your brain. The acoustics 00:21:56.730 --> 00:21:59.950 seem to be the primary driver. But if you're 00:21:59.950 --> 00:22:03.009 a five -ton animal living in the hot, humid Cretaceous 00:22:03.009 --> 00:22:05.849 summer, having a built -in radiator on your head 00:22:05.849 --> 00:22:08.730 is definitely a fantastic bonus. Because it's 00:22:08.730 --> 00:22:11.009 a multi -purpose tool. Nature loves efficiency. 00:22:11.680 --> 00:22:13.539 If you're going to build a big, expensive structure, 00:22:13.740 --> 00:22:15.380 you might as well use it for everything you can. 00:22:15.759 --> 00:22:17.539 So yeah, it's a boombox, it's a billboard, and 00:22:17.539 --> 00:22:20.200 it's an AC unit, all in one. A boombox, a billboard, 00:22:20.299 --> 00:22:23.859 and an AC unit. I love that. Now, we've been 00:22:23.859 --> 00:22:25.680 talking about the Parasaurolophus as if it's 00:22:25.680 --> 00:22:27.980 just one thing, but the notes highlight that 00:22:27.980 --> 00:22:30.319 there are three distinct, recognized species, 00:22:30.579 --> 00:22:33.480 and the differences between them actually caused 00:22:33.480 --> 00:22:35.619 a massive fight in the scientific community. 00:22:35.960 --> 00:22:38.700 They did. It's easy to lump them together, but 00:22:38.700 --> 00:22:40.720 the differences are crucial and tell us a lot. 00:22:41.579 --> 00:22:44.940 So the three main players on the field are, first, 00:22:45.220 --> 00:22:48.059 Parasaurolophus walkeri. That's the classic one, 00:22:48.099 --> 00:22:50.160 the type species from Alberta that William Parks 00:22:50.160 --> 00:22:52.440 found. Straight crest. Mostly straight with a 00:22:52.440 --> 00:22:55.500 slight graceful curve. And its internal tubes 00:22:55.500 --> 00:22:58.799 are relatively simple. Then you have Parasaurolophus 00:22:58.799 --> 00:23:01.299 tubicin, the giant trumpeter from New Mexico. 00:23:01.500 --> 00:23:03.579 The loud one, the one they CT scanned. The loud 00:23:03.579 --> 00:23:05.799 one. It's the biggest of the three, and its crest 00:23:05.799 --> 00:23:08.420 is longer and much more complex inside. It has 00:23:08.420 --> 00:23:11.339 more chambers, more loops. It was probably capable 00:23:11.339 --> 00:23:14.460 of a greater range of sounds. And then we have 00:23:14.460 --> 00:23:17.410 the troublemaker. Parasaurolophus sardicrystatus. 00:23:17.730 --> 00:23:19.789 Sardicrystatus. Why is he the troublemaker? Because 00:23:19.789 --> 00:23:22.490 he just looks wrong. Walkery and Tubison have 00:23:22.490 --> 00:23:24.630 these long, backward -sweeping tubes. They look 00:23:24.630 --> 00:23:27.329 elegant. Sardicrystatus is smaller, and its crest 00:23:27.329 --> 00:23:30.009 is short and curves down sharply, almost tucking 00:23:30.009 --> 00:23:32.650 in against the back of the skull. It looks unfinished. 00:23:33.230 --> 00:23:35.089 That's a great way to put it. It looks like a 00:23:35.089 --> 00:23:37.250 Parasaurolophus that gave up halfway through 00:23:37.250 --> 00:23:39.789 growing its crest. And that appearance led to 00:23:39.789 --> 00:23:43.250 the female hypothesis, right? Exactly. In biology, 00:23:43.430 --> 00:23:45.390 when you see two animals in the same place that 00:23:45.390 --> 00:23:47.650 look similar, but one is big and robust with 00:23:47.650 --> 00:23:50.029 a fancy ornament, and the other is smaller and 00:23:50.029 --> 00:23:54.190 more gressle, your first instinct is sexual dimorphism. 00:23:54.650 --> 00:23:58.569 Males versus females. Sure. So the paleontologist 00:23:58.569 --> 00:24:00.930 James Hobson suggested that maybe Serticostatus 00:24:00.930 --> 00:24:03.829 wasn't a different species at all. Maybe it was 00:24:03.829 --> 00:24:06.730 just the female form of one of the other species, 00:24:06.910 --> 00:24:09.069 like Tubicin. Which happens all the time in nature. 00:24:09.430 --> 00:24:13.210 Male deer have antlers, females don't. Male peacocks 00:24:13.210 --> 00:24:15.569 have the giant tail. Females don't. It was a 00:24:15.569 --> 00:24:18.390 very solid, very elegant theory. It tidied everything 00:24:18.390 --> 00:24:20.730 up nicely. Oh, the short curved crests are the 00:24:20.730 --> 00:24:22.970 girls and the long straight crests are the boys. 00:24:23.569 --> 00:24:26.750 Simple. But then stratigraphy, the study of rock 00:24:26.750 --> 00:24:29.170 layers, kind of ruined the party. How so? What 00:24:29.170 --> 00:24:31.569 did the rocks say? While P. sardicristatus is 00:24:31.569 --> 00:24:33.670 found in different rock layers than P. tubuson 00:24:33.670 --> 00:24:36.269 is, especially in New Mexico, they are separated 00:24:36.269 --> 00:24:38.990 by time and geography. You usually don't find 00:24:38.990 --> 00:24:41.109 the males of a species living a million years 00:24:41.109 --> 00:24:42.789 apart from the females. Yeah, that makes mating 00:24:42.789 --> 00:24:45.109 very, very difficult. The long -distance relationship 00:24:45.109 --> 00:24:49.140 from hell. Exactly. So the consensus now is that 00:24:49.140 --> 00:24:51.880 Cerda crustatus is a valid, distinct species, 00:24:52.160 --> 00:24:55.299 perhaps a more primitive or basal form. Or maybe 00:24:55.299 --> 00:24:57.380 it just occupied a different ecological niche 00:24:57.380 --> 00:25:00.480 where a shorter crest was more advantageous for 00:25:00.480 --> 00:25:02.619 some reason. But speaking of crest shape and 00:25:02.619 --> 00:25:05.609 how they grow, we have to talk about Joe. Everyone 00:25:05.609 --> 00:25:08.869 loves Joe. Joe is a rock star. Who is Joe? Joe 00:25:08.869 --> 00:25:12.750 is the nickname for specimen ram 14 ,000. It 00:25:12.750 --> 00:25:15.329 was found in Utah in the Kuyperowitz Formation 00:25:15.329 --> 00:25:18.609 back in 2009 and was found by a high school student, 00:25:18.670 --> 00:25:21.329 actually, a kid named Kevin Terrace. He was volunteering 00:25:21.329 --> 00:25:23.450 on a dig and saw a little bit of bone sticking 00:25:23.450 --> 00:25:26.309 out of a rock that seasoned professional paleontologists 00:25:26.309 --> 00:25:29.089 had walked right past for years. Good eye on 00:25:29.089 --> 00:25:31.529 that kid. An incredible eye. And it turned out 00:25:31.529 --> 00:25:34.069 to be the most complete and by far the youngest 00:25:34.069 --> 00:25:36.380 paras... saurolophus we have ever found. How 00:25:36.380 --> 00:25:39.539 young are we talking? A baby. Based on bone histology, 00:25:39.720 --> 00:25:41.400 it was less than a year old. It was only about 00:25:41.400 --> 00:25:44.279 2 .5 meters long, so about eight feet. An eight 00:25:44.279 --> 00:25:46.599 foot long baby? Yeah. That's still bigger than 00:25:46.599 --> 00:25:49.640 a human? They grew fast. Insanely fast. These 00:25:49.640 --> 00:25:51.839 animals were putting on mass at an incredible 00:25:51.839 --> 00:25:54.339 rate to get out of that bite size for predator 00:25:54.339 --> 00:25:57.420 stage as quickly as possible. But the real shocker 00:25:57.420 --> 00:26:00.119 was the head. Based on the adult skulls, you'd 00:26:00.119 --> 00:26:02.799 expect maybe a tiny little tube starting to form. 00:26:02.880 --> 00:26:05.940 A little snorkel. Joe didn't have a tube. So 00:26:05.940 --> 00:26:08.539 what did he have? He had a bump. A little low 00:26:08.539 --> 00:26:11.740 hemispherical nub right on his forehead. It looked 00:26:11.740 --> 00:26:14.640 more like a pimple than a crest. So they aren't 00:26:14.640 --> 00:26:17.450 born with a trombone. It has to grow. No. And 00:26:17.450 --> 00:26:19.230 that tells us something really crucial about 00:26:19.230 --> 00:26:21.750 their life history. The crest starts growing 00:26:21.750 --> 00:26:25.150 very early, and it grows very, very fast. In 00:26:25.150 --> 00:26:27.650 other related crested dinosaurs, like Corythosaurus, 00:26:28.109 --> 00:26:30.210 the crest doesn't really pop up until they are 00:26:30.210 --> 00:26:32.450 about half grown. They look like generic flat 00:26:32.450 --> 00:26:35.549 -headed duck bills for a long time. But not Parasaurolophus. 00:26:35.769 --> 00:26:38.190 No, Parasaurolophus kids were pushing that bone 00:26:38.190 --> 00:26:40.589 up almost immediately. It was a priority. Which 00:26:40.589 --> 00:26:43.250 implies that even for the juveniles, that signal, 00:26:43.390 --> 00:26:46.109 or maybe the beginnings of that sound, was vital. 00:26:46.539 --> 00:26:48.140 Maybe for staying in touch with the parents. 00:26:48.319 --> 00:26:51.480 That's one possibility. Or it could be that the 00:26:51.480 --> 00:26:54.440 final adult structure was so massive and complex 00:26:54.440 --> 00:26:56.680 that they simply had to start growing it early 00:26:56.680 --> 00:26:58.839 just to get it finished in time for adulthood. 00:26:59.519 --> 00:27:02.259 Either way, it implies a life that was strictly 00:27:02.259 --> 00:27:05.000 governed by that crest. It was the center of 00:27:05.000 --> 00:27:08.259 their entire existence. I want to pivot now to 00:27:08.259 --> 00:27:10.299 something that makes these animals feel real. 00:27:10.460 --> 00:27:12.660 Not just biological machines, but individuals. 00:27:13.059 --> 00:27:16.279 Because we have a specific and kind of sad story 00:27:16.279 --> 00:27:19.059 about the very first Parasaurolophus ever found. 00:27:19.480 --> 00:27:22.559 The holotype. The paleopathology, yes. This is 00:27:22.559 --> 00:27:24.599 one of my favorite details in this whole story 00:27:24.599 --> 00:27:26.940 because it was misunderstood for almost a century. 00:27:27.200 --> 00:27:29.579 Right. So when William Parks found this skeleton 00:27:29.579 --> 00:27:32.859 back in the 1920s, he noticed this strange notch 00:27:32.859 --> 00:27:35.640 in the spine. Right where the neck meets the 00:27:35.640 --> 00:27:37.579 back, the vertebrae are kind of crunched down 00:27:37.579 --> 00:27:39.940 in a V shape. And Parks, working with what he 00:27:39.940 --> 00:27:42.380 knew, thought it was a natural feature. He actually 00:27:42.380 --> 00:27:44.680 proposed that a huge ligament ran from the tip 00:27:44.680 --> 00:27:46.819 of the crest all the way back to the notch in 00:27:46.819 --> 00:27:49.460 the spine. Like a suspension bridge cable. Exactly. 00:27:49.640 --> 00:27:52.400 He thought, wow, that head and crest are so huge 00:27:52.400 --> 00:27:54.900 and heavy, the neck muscles can't possibly hold 00:27:54.900 --> 00:27:58.220 it up alone. So he imagined this thick ligament 00:27:58.220 --> 00:28:00.730 acting as a tether. holding the head up which 00:28:00.730 --> 00:28:03.170 we now know is completely wrong completely wrong 00:28:03.170 --> 00:28:05.650 there's no anatomical precedent for that in any 00:28:05.650 --> 00:28:08.549 animal we know of the main neutral ligament which 00:28:08.549 --> 00:28:11.029 supports the head attaches to the base of the 00:28:11.029 --> 00:28:13.890 skull not to the tip of a fancy hollow crest 00:28:13.890 --> 00:28:16.410 so if it's not a ligament anchor what is it it's 00:28:16.410 --> 00:28:21.680 a broken back a healed but severe injury That's 00:28:21.680 --> 00:28:24.799 a lot more dramatic. A study in 2020 by a paleontologist 00:28:24.799 --> 00:28:27.740 named Pertotso really took a close look at this 00:28:27.740 --> 00:28:30.640 with modern technology. The bones are clearly 00:28:30.640 --> 00:28:33.319 deformed. They were crushed by some kind of massive 00:28:33.319 --> 00:28:36.220 blunt force trauma. And the leading theory is 00:28:36.220 --> 00:28:38.940 the falling tree hypothesis. OK, paint the picture 00:28:38.940 --> 00:28:41.579 for us. Imagine the late Cretaceous of Alberta. 00:28:41.799 --> 00:28:44.099 It's a storm. The weather patterns were much 00:28:44.099 --> 00:28:45.839 more intense back then. You have high winds, 00:28:46.000 --> 00:28:48.319 maybe a hurricane -like storm coming off that 00:28:48.319 --> 00:28:50.720 big interior seaway. And this animal is hiding. 00:28:50.759 --> 00:28:52.380 Settling in the forest, maybe with its herd, 00:28:52.519 --> 00:28:55.259 trying to stay low and ride it out. It's loud. 00:28:55.380 --> 00:28:58.299 It's wet. It's terrifying. In a massive tree 00:28:58.299 --> 00:29:00.779 trunk, maybe a redwood relative, something huge 00:29:00.779 --> 00:29:04.059 snaps in the wind and crashes down. It strikes 00:29:04.059 --> 00:29:06.400 the animal right across the shoulders, just behind 00:29:06.400 --> 00:29:09.660 the neck. A direct hit. A direct hit from a tree. 00:29:09.720 --> 00:29:12.180 It would have been crushing. It smashed the tall 00:29:12.180 --> 00:29:14.619 neural spines of the vertebrae, compressed the 00:29:14.619 --> 00:29:17.180 vertebral column itself, and likely broke several 00:29:17.180 --> 00:29:20.440 ribs. It would have been an agonizing, crippling 00:29:20.440 --> 00:29:23.759 injury. And usually in the wild, a broken back 00:29:23.759 --> 00:29:26.619 like that means death. You can't move, you starve, 00:29:26.940 --> 00:29:29.619 or a predator finds you and eats you. That's 00:29:29.619 --> 00:29:32.579 the miracle of the specimen. The bone shows extensive 00:29:32.579 --> 00:29:35.140 signs of healing. There's a lot of remodeled 00:29:35.140 --> 00:29:37.750 bone, calluses where the fractures were. This 00:29:37.750 --> 00:29:39.950 wasn't a death blow. It survived. It survived. 00:29:40.089 --> 00:29:42.549 It lived for months, maybe even years after this 00:29:42.549 --> 00:29:45.289 injury. The bone grew back together, but it healed 00:29:45.289 --> 00:29:48.329 in that deformed V -shaped notch that Parks saw. 00:29:48.549 --> 00:29:51.369 That is just incredible. It tells us two amazing 00:29:51.369 --> 00:29:55.549 things. One, Parasaurolophus was tough as nails. 00:29:56.269 --> 00:29:58.750 This animal walked around, ate, and interacted 00:29:58.750 --> 00:30:01.170 with its herd while recovering from a major spinal 00:30:01.170 --> 00:30:03.549 fracture. It must have been in constant pain, 00:30:03.630 --> 00:30:06.289 but it kept going. And the second thing? It implies 00:30:06.289 --> 00:30:09.029 a level of social support. You think the herd 00:30:09.029 --> 00:30:11.930 protected it? It's certainly possible. An animal 00:30:11.930 --> 00:30:14.390 that injured would have been slower, more vulnerable 00:30:14.390 --> 00:30:18.430 to predators. If it survived for years, it suggests 00:30:18.430 --> 00:30:20.829 it wasn't immediately picked off or left behind. 00:30:21.089 --> 00:30:23.430 It stayed with the group, and the group provided 00:30:23.430 --> 00:30:26.630 some measure of safety. It adds this whole layer 00:30:26.630 --> 00:30:28.890 of biography to the bones. This wasn't just a 00:30:28.890 --> 00:30:31.890 generic specimen number. It was a survivor. It 00:30:31.890 --> 00:30:34.250 had a really, really bad day, and it lived to 00:30:34.250 --> 00:30:36.849 tell the tale. Let's widen the lens a bit. We've 00:30:36.849 --> 00:30:38.410 looked at the animal in detail. Let's look at 00:30:38.410 --> 00:30:41.190 the world it survived in. Where are we geographically 00:30:41.190 --> 00:30:43.289 when we talk about Parasaurovus? We are in a 00:30:43.289 --> 00:30:46.029 place called Laramidia. During the late Cretaceous, 00:30:46.089 --> 00:30:49.490 North America was split in half by a giant inland 00:30:49.490 --> 00:30:53.019 sea. the Western Interior Seaway. It ran all 00:30:53.019 --> 00:30:54.980 the way from the Arctic Ocean down to the Gulf 00:30:54.980 --> 00:30:58.059 of Mexico. The landmass to the east is called 00:30:58.059 --> 00:31:01.549 Appalachia. The long, thin landmass to the west, 00:31:01.730 --> 00:31:04.930 stretching from Alaska down to Mexico, is Laramidia. 00:31:05.150 --> 00:31:07.950 This is where all the famous dinosaurs like T 00:31:07.950 --> 00:31:10.930 -Rex, Triceratops, and Parasaurolophus lived. 00:31:11.130 --> 00:31:13.930 But it wasn't just one big uniform forest, right? 00:31:13.970 --> 00:31:16.150 The environments were different. No, it was highly 00:31:16.150 --> 00:31:18.289 regional, which is why we see different species 00:31:18.289 --> 00:31:20.809 in different places. In the north, in Alberta, 00:31:21.049 --> 00:31:23.009 where our survivor with the broken back lived, 00:31:23.309 --> 00:31:26.150 you had the dinosaur park formation. This place 00:31:26.150 --> 00:31:29.099 was crowded. Crowded with what? Herds of Centrosaurus, 00:31:29.339 --> 00:31:31.359 Styracosaurus, lots of other kinds of dovetails 00:31:31.359 --> 00:31:33.119 like Corithosaurus. It was like the Serengeti 00:31:33.119 --> 00:31:35.819 of the Cretaceous. But strangely, Parasaurolophus 00:31:35.819 --> 00:31:38.039 walkeri was actually pretty rare there. Just 00:31:38.039 --> 00:31:40.200 passing through. Maybe. Or maybe it preferred 00:31:40.200 --> 00:31:42.440 the uplands away from the crowded floodplains. 00:31:42.440 --> 00:31:44.519 It's actually one of the rarer hadrosaurs in 00:31:44.519 --> 00:31:47.759 that particular fauna. But as you go south into 00:31:47.759 --> 00:31:50.299 New Mexico and Utah, the picture changes completely. 00:31:50.990 --> 00:31:53.230 Utah was the jungle, right? The Kuiperowitz formation. 00:31:53.309 --> 00:31:55.269 That's right. That was the home of Joe the Baby. 00:31:55.529 --> 00:32:00.150 It was a hot, humid, swampy jungle. Very wet. 00:32:00.269 --> 00:32:03.150 Lots of rivers and floodplains. And the predators 00:32:03.150 --> 00:32:05.210 were different. In the north, in Alberta, you 00:32:05.210 --> 00:32:07.549 had to worry about Gorgosaurus. In Utah, you 00:32:07.549 --> 00:32:10.609 had Teratophonius, another Tyrannosaur, but you 00:32:10.609 --> 00:32:13.309 also had something much, much worse in the water. 00:32:13.769 --> 00:32:16.369 Deinosuchus. The Terror Crocodile. How big are 00:32:16.369 --> 00:32:18.410 we talking when we say Terror Crocodile? We are 00:32:18.410 --> 00:32:20.769 talking about an alligatoroid that grew up to 00:32:20.769 --> 00:32:25.200 12 meters long. That's 40 feet. It weighed more 00:32:25.200 --> 00:32:28.099 than the T -Rex of its time. Its bite force was 00:32:28.099 --> 00:32:30.339 strong enough to crush giant sea turtle shells 00:32:30.339 --> 00:32:32.980 and dinosaur bones like they were popcorn. So 00:32:32.980 --> 00:32:34.799 if our parasaurolophus goes down to the river 00:32:34.799 --> 00:32:36.740 to get a drink. It is entering the kill zone. 00:32:36.880 --> 00:32:38.799 We actually have had parasaur bones from that 00:32:38.799 --> 00:32:40.819 formation with Deimosuchus bite marks on them. 00:32:40.960 --> 00:32:43.380 This was a world where the water could and dead 00:32:43.380 --> 00:32:46.720 eat you. And yet the southern species P. tubicin 00:32:46.720 --> 00:32:49.160 and Serticristatus seem to be more common in 00:32:49.160 --> 00:32:51.599 these swampy wet areas. They were living right 00:32:51.599 --> 00:32:53.880 next to the danger. Which means. Maybe that's 00:32:53.880 --> 00:32:56.059 why they needed such a sophisticated long distance 00:32:56.059 --> 00:32:58.359 communication system. You need to be able to 00:32:58.359 --> 00:33:01.400 warn the rest of the herd about the 40 foot crocodile 00:33:01.400 --> 00:33:03.339 lurking in the river. It makes a lot of sense. 00:33:03.559 --> 00:33:06.119 A low frequency rumble. That means watch the 00:33:06.119 --> 00:33:08.529 water. I have to ask about one last physical 00:33:08.529 --> 00:33:11.089 detail because it ties into how a lot of people 00:33:11.089 --> 00:33:13.130 first saw this dinosaur, especially if they're 00:33:13.130 --> 00:33:15.930 of a certain age. If you watch Disney's Fantasia. 00:33:16.109 --> 00:33:19.849 Oh, the Rite of Spring sequence, a classic. For 00:33:19.849 --> 00:33:22.150 all its inaccuracies, it was beautiful. It was. 00:33:22.529 --> 00:33:25.069 And in the movie, the Parasaurolophus has this 00:33:25.069 --> 00:33:28.349 sail, a flap of skin connecting the crest to 00:33:28.349 --> 00:33:30.230 the back of the neck. It looks kind of like a 00:33:30.230 --> 00:33:32.990 basilisk lizard. It looks very, very cool. It 00:33:32.990 --> 00:33:34.529 does look cool. I'll admit that. Is there any 00:33:34.529 --> 00:33:36.490 truth to that? Or is that just Disney magic? 00:33:36.960 --> 00:33:39.819 That idea actually goes way back to Barnum Brown, 00:33:40.039 --> 00:33:44.000 a very famous fossil hunter around 1912. He was 00:33:44.000 --> 00:33:46.440 describing a related animal and saw some texture 00:33:46.440 --> 00:33:48.859 on the back of a crest and hypothesized there 00:33:48.859 --> 00:33:51.079 might have been a skin flap. And because of that 00:33:51.079 --> 00:33:53.319 notch in the spine of the Parasaurolophus holotype 00:33:53.319 --> 00:33:56.920 we talked about earlier, artists just, they connected 00:33:56.920 --> 00:33:59.180 the dots. They thought the sail attached to the 00:33:59.180 --> 00:34:01.220 broken back. Exactly. They thought, oh, that 00:34:01.220 --> 00:34:03.339 notch must be the anchor point where the skin 00:34:03.339 --> 00:34:06.650 flap attaches. So it became a popular look. But 00:34:06.650 --> 00:34:08.610 now that we know the notch is an injury, the 00:34:08.610 --> 00:34:11.170 anchor point is gone. And there's no other soft 00:34:11.170 --> 00:34:13.329 tissue evidence to support a big sail like that. 00:34:13.710 --> 00:34:16.389 So most modern paleo artists have ditched it. 00:34:16.469 --> 00:34:19.070 The crest stands free. I think it looks better 00:34:19.070 --> 00:34:21.050 that way, honestly. It highlights the instrument 00:34:21.050 --> 00:34:23.489 itself. I agree. It's striking enough on its 00:34:23.489 --> 00:34:26.150 own. It doesn't need any accessories. So let's 00:34:26.150 --> 00:34:29.090 wrap this all up. We started this deep dive with 00:34:29.090 --> 00:34:31.690 a silhouette. A plastic toy that basically every 00:34:31.690 --> 00:34:34.250 kid knows. And we've ended up with this highly 00:34:34.250 --> 00:34:37.630 complex, socially sophisticated biological entity. 00:34:37.889 --> 00:34:40.110 Yeah, we've gone from a snorkel -using water 00:34:40.110 --> 00:34:43.409 beast to a land -dwelling five -ton athlete that 00:34:43.409 --> 00:34:45.710 could run on two legs. We've realized the crest 00:34:45.710 --> 00:34:48.909 wasn't a weapon or a snorkel, but a high -fidelity 00:34:48.909 --> 00:34:51.829 subwoofer capable of broadcasting messages for 00:34:51.829 --> 00:34:54.210 miles. We've learned they grew up incredibly 00:34:54.210 --> 00:34:56.849 fast, starting with just a little bump on their 00:34:56.849 --> 00:34:59.090 heads that blossomed into this incredible structure. 00:34:59.610 --> 00:35:01.849 And that they were resilient enough as individuals 00:35:01.849 --> 00:35:04.829 to survive broken backs and tough enough as a 00:35:04.829 --> 00:35:07.909 species to live in crocodile infested swamps. 00:35:07.929 --> 00:35:09.969 It really, really changes the way you look at 00:35:09.969 --> 00:35:12.010 a museum skeleton. It's not just a collection 00:35:12.010 --> 00:35:14.329 of bones anymore. That's the goal. When you look 00:35:14.329 --> 00:35:17.570 at that skull now, don't just see a bone. Try 00:35:17.570 --> 00:35:20.579 to hear the sound. Imagine a foggy morning in 00:35:20.579 --> 00:35:23.340 the Cretaceous and that low vibrating hum rolling 00:35:23.340 --> 00:35:26.340 across the landscape. That is the reality of 00:35:26.340 --> 00:35:29.400 Parasaurolophus. So here is a final thought for 00:35:29.400 --> 00:35:32.199 you to chew on. If they had this hardware, this 00:35:32.199 --> 00:35:34.659 incredible ability to send specific, complex, 00:35:34.800 --> 00:35:37.260 low frequency signals, what were they really 00:35:37.260 --> 00:35:39.880 saying? We assume simple things, you know, food 00:35:39.880 --> 00:35:42.619 here, danger there. But animals with complex 00:35:42.619 --> 00:35:45.139 communication often have complex social structures. 00:35:45.300 --> 00:35:47.719 Were they calling to specific individuals? Did 00:35:47.719 --> 00:35:49.440 they have unique voices that their herd mates 00:35:49.440 --> 00:35:51.579 could recognize? Were they identifying their 00:35:51.579 --> 00:35:53.719 own offspring in the creche of thousands by their 00:35:53.719 --> 00:35:56.440 specific call? The hardware suggests a level 00:35:56.440 --> 00:35:59.199 of communicative complexity that we usually reserve 00:35:59.199 --> 00:36:02.239 for animals like whales or primates. It's very 00:36:02.239 --> 00:36:04.559 possible there was a lot more going on inside 00:36:04.559 --> 00:36:06.860 that crested head than we give them credit for. 00:36:07.079 --> 00:36:09.380 So next time you see that dinosaur, don't just 00:36:09.380 --> 00:36:12.619 ask what the creche was for. Ask yourself, what 00:36:12.619 --> 00:36:14.860 was it saying? Always ask the next question. 00:36:15.199 --> 00:36:17.400 Thanks for listening to The Deep Dive. We'll 00:36:17.400 --> 00:36:18.280 catch you on the next one.