1 00:00:10,000 --> 00:00:15,000 I'm here in Patagonia in the southern part of South America because, 2 00:00:15,000 --> 00:00:20,000 a few years ago, a man looking for one of his lost sheep found 3 00:00:20,000 --> 00:00:25,000 a simply gigantic bone sticking out of a rock - 4 00:00:25,000 --> 00:00:27,000 a bone that was going to astonish science. 5 00:00:29,000 --> 00:00:33,000 That first bone led to the discovery of over 200 others. 6 00:00:38,000 --> 00:00:44,000 They were all huge - so big that they could only have come from a dinosaur. 7 00:00:44,000 --> 00:00:47,000 And what a dinosaur it would turn out to be! 8 00:00:50,000 --> 00:00:52,000 One that seems to defy the laws of nature. 9 00:00:55,000 --> 00:00:58,000 These bones are part of a skeleton that has remained hidden 10 00:00:58,000 --> 00:01:02,000 and marvellously preserved for 100 million years. 11 00:01:06,000 --> 00:01:10,000 'An international team of scientists assembled to try 12 00:01:10,000 --> 00:01:13,000 'and work out what sort of dinosaur it belonged to.' 13 00:01:15,000 --> 00:01:18,000 It's like a palaeontological crime scene! 14 00:01:19,000 --> 00:01:23,000 Each bone is an important piece of evidence that can give us 15 00:01:23,000 --> 00:01:27,000 information as to what the living creature was actually like. 16 00:01:27,000 --> 00:01:30,000 We'll use the latest forensic technology, 17 00:01:30,000 --> 00:01:35,000 we'll compare it with how giant animals live today 18 00:01:35,000 --> 00:01:40,000 and we'll build a full-size skeleton of this stupendous creature. 19 00:01:42,000 --> 00:01:47,000 And we will try and work out in detail what it looked like 20 00:01:47,000 --> 00:01:48,000 when it was alive. 21 00:01:52,000 --> 00:01:54,000 HE GASPS 22 00:01:54,000 --> 00:01:56,000 Absolutely amazing! 23 00:01:57,000 --> 00:02:00,000 Could it really have been the biggest animal 24 00:02:00,000 --> 00:02:02,000 ever to walk the earth? 25 00:02:21,000 --> 00:02:24,000 Patagonia in southern Argentina. 26 00:02:28,000 --> 00:02:32,000 Like many detective stories, this one began by chance. 27 00:02:35,000 --> 00:02:38,000 A shepherd stumbled across the tip of a huge bone 28 00:02:38,000 --> 00:02:40,000 poking out of the ground. 29 00:02:42,000 --> 00:02:43,000 HORSE SNORTS 30 00:02:48,000 --> 00:02:52,000 Experts from Patagonia's premier palaeontological museum 31 00:02:52,000 --> 00:02:55,000 confirmed it was part of a dinosaur. 32 00:02:55,000 --> 00:02:56,000 THEY SPEAK IN OWN LANGUAGE 33 00:03:00,000 --> 00:03:05,000 But they didn't realise at the time what a truly extraordinary one 34 00:03:05,000 --> 00:03:06,000 it would prove to be. 35 00:03:12,000 --> 00:03:15,000 Dinosaurs of many kinds roamed all over these lands 36 00:03:15,000 --> 00:03:17,000 in the southern end of South America 37 00:03:17,000 --> 00:03:21,000 during what's known as the Cretaceous period, 38 00:03:21,000 --> 00:03:24,000 between 66 and 145 million years ago. 39 00:03:26,000 --> 00:03:30,000 The largest were plant-eaters known as sauropods. 40 00:03:30,000 --> 00:03:35,000 And the largest of them were the titanosaurs. 41 00:03:37,000 --> 00:03:40,000 Giant titanosaur bones are comparatively rare 42 00:03:40,000 --> 00:03:43,000 so very little is known about these dinosaurs. 43 00:03:48,000 --> 00:03:51,000 This new discovery could change all that. 44 00:03:57,000 --> 00:04:03,000 'Like many people, young and old, I'm fascinated by dinosaurs, 45 00:04:03,000 --> 00:04:05,000 'so the chance to join this investigation 46 00:04:05,000 --> 00:04:08,000 'is just too good an opportunity to miss.' 47 00:04:08,000 --> 00:04:10,000 Oh, I'd love to have a go! 48 00:04:10,000 --> 00:04:12,000 HE LAUGHS 49 00:04:12,000 --> 00:04:13,000 I'm sure they'd let you. 50 00:04:13,000 --> 00:04:14,000 HE LAUGHS 51 00:04:14,000 --> 00:04:18,000 'Of course, it's the giants in particular that capture 52 00:04:18,000 --> 00:04:19,000 'the imagination.' 53 00:04:22,000 --> 00:04:24,000 The first sauropods to appear on earth 54 00:04:24,000 --> 00:04:26,000 were comparatively small creatures. 55 00:04:26,000 --> 00:04:30,000 This is the cast of the thigh bone of one of them. 56 00:04:30,000 --> 00:04:34,000 It's not even as big as my thigh bone. 57 00:04:34,000 --> 00:04:41,000 But after about 20 million years, some had become pretty big. 58 00:04:41,000 --> 00:04:45,000 This is a thigh bone from one of those creatures. 59 00:04:45,000 --> 00:04:46,000 But then, after that... 60 00:04:48,000 --> 00:04:53,000 ..our giant appeared. This is its thigh bone. 61 00:04:54,000 --> 00:04:57,000 It's the largest ever found. 62 00:05:06,000 --> 00:05:10,000 Coming across such a bone in your back yard must be quite a shock. 63 00:05:10,000 --> 00:05:13,000 Just ask farm owner Alba Maio. 64 00:05:16,000 --> 00:05:18,000 HENS CLUCK 65 00:05:18,000 --> 00:05:20,000 TRANSLATION: 66 00:05:22,000 --> 00:05:23,000 SHE LAUGHS 67 00:05:23,000 --> 00:05:26,000 TRANSLATION: 68 00:05:37,000 --> 00:05:41,000 Before long, a whole team of fossil-hunting scientists 69 00:05:41,000 --> 00:05:43,000 arrives and starts work. 70 00:05:55,000 --> 00:05:59,000 The thighbone proves to be eight feet, 2.4 metres long. 71 00:06:07,000 --> 00:06:12,000 It's preserved in extraordinary detail, and detail will be 72 00:06:12,000 --> 00:06:15,000 critical to the forensic examination that will follow. 73 00:06:25,000 --> 00:06:30,000 The research team soon turn the site into a vast quarry. 74 00:06:39,000 --> 00:06:44,000 It proves to be one of the biggest dinosaur finds of the century. 75 00:06:47,000 --> 00:06:51,000 Bone after bone emerge from the rocks. 76 00:06:51,000 --> 00:06:53,000 THEY LAUGH 77 00:06:56,000 --> 00:06:58,000 We just found another bone right here. 78 00:06:58,000 --> 00:07:00,000 We weren't expecting it at all. 79 00:07:00,000 --> 00:07:03,000 We just start digging and find it. 80 00:07:05,000 --> 00:07:08,000 Until recently, giant titanosaurs 81 00:07:08,000 --> 00:07:11,000 have only been known from a dozen bones 82 00:07:11,000 --> 00:07:16,000 and our team have already found more than ten times as many. 83 00:07:21,000 --> 00:07:25,000 Dr Diego Pol is the chief palaeontologist 84 00:07:25,000 --> 00:07:27,000 leading the investigation. 85 00:07:27,000 --> 00:07:29,000 If you really want to know 86 00:07:29,000 --> 00:07:34,000 what a really gigantic dinosaur looked like, this quarry here 87 00:07:34,000 --> 00:07:36,000 has the potential to answer that question 88 00:07:36,000 --> 00:07:38,000 and that's really exciting for us. 89 00:07:40,000 --> 00:07:41,000 It's really impressive. 90 00:07:41,000 --> 00:07:45,000 When you stand by one of these bones, you really feel tiny. 91 00:07:47,000 --> 00:07:51,000 With so much new evidence, there is a chance of discovering 92 00:07:51,000 --> 00:07:55,000 all kinds of new facts about the mysterious titanosaurs. 93 00:07:58,000 --> 00:08:01,000 It's like a palaeontological crime scene. 94 00:08:01,000 --> 00:08:02,000 It's a really unique thing 95 00:08:02,000 --> 00:08:06,000 that you will not find anywhere else in the world. 96 00:08:09,000 --> 00:08:11,000 Patagonia's harsh weather 97 00:08:11,000 --> 00:08:13,000 makes uncovering the fossils exhausting, 98 00:08:13,000 --> 00:08:18,000 but it also endangers the newly-exposed fossils. 99 00:08:20,000 --> 00:08:22,000 THUNDER RUMBLES 100 00:08:22,000 --> 00:08:24,000 A lot of damage from the rain 101 00:08:24,000 --> 00:08:27,000 so we need to protect the bones that are at risk. 102 00:08:27,000 --> 00:08:32,000 I'm really concerned that this already has some cracks. 103 00:08:33,000 --> 00:08:35,000 If the bones aren't protected, 104 00:08:35,000 --> 00:08:38,000 tiny details on their surface could be lost. 105 00:08:44,000 --> 00:08:47,000 To protect the bones, they're covered with, of all things, 106 00:08:47,000 --> 00:08:51,000 wet toilet paper and plaster of Paris. 107 00:08:51,000 --> 00:08:56,000 It's like putting a plaster cast on a broken leg. 108 00:08:58,000 --> 00:09:01,000 There's a rush to get them back to the museum 109 00:09:01,000 --> 00:09:04,000 to begin examining them in minute detail. 110 00:09:09,000 --> 00:09:13,000 A new road has been specially built to enable them 111 00:09:13,000 --> 00:09:16,000 to be transported without too much jolting. 112 00:09:20,000 --> 00:09:25,000 Once at the museum laboratory, the detailed detective work begins. 113 00:09:33,000 --> 00:09:37,000 It's a chance to start putting flesh on bones. 114 00:09:37,000 --> 00:09:41,000 Some really big muscle was going in here. 115 00:09:41,000 --> 00:09:45,000 This animal was so big that it certainly needed 116 00:09:45,000 --> 00:09:48,000 really powerful muscles and very strong attachments 117 00:09:48,000 --> 00:09:51,000 into the bones. 118 00:10:01,000 --> 00:10:04,000 This is a giant vertebra, one of the bones of the spine, 119 00:10:04,000 --> 00:10:07,000 and it's a very important find. 120 00:10:07,000 --> 00:10:10,000 That's because it's likely to provide crucial evidence 121 00:10:10,000 --> 00:10:14,000 for identifying the species of our dinosaur. 122 00:10:19,000 --> 00:10:22,000 Despite weighing up to half a tonne, 123 00:10:22,000 --> 00:10:24,000 these fossils are surprisingly fragile. 124 00:10:29,000 --> 00:10:30,000 It's all rather nerve-racking. 125 00:10:32,000 --> 00:10:36,000 One bone like this has already cracked in half without warning. 126 00:10:40,000 --> 00:10:42,000 Bravo! 127 00:10:52,000 --> 00:10:55,000 THEY LAUGH 128 00:10:55,000 --> 00:10:58,000 And so this is the position as it was in life 129 00:10:58,000 --> 00:11:01,000 with the centre of the backbone there, 130 00:11:01,000 --> 00:11:03,000 then this is the crest on the top. 131 00:11:03,000 --> 00:11:06,000 Right, right, and this belongs to the middle part of the thorax. 132 00:11:06,000 --> 00:11:09,000 Right about here. About that. Yeah, yeah. 133 00:11:09,000 --> 00:11:13,000 'Many more weeks of detailed examination 134 00:11:13,000 --> 00:11:16,000 'will be needed before the backbones reveal all their secrets.' 135 00:11:19,000 --> 00:11:23,000 Surprisingly, perhaps, one of the first things 136 00:11:23,000 --> 00:11:27,000 the team was able to deduce about our titanosaur is its weight. 137 00:11:29,000 --> 00:11:32,000 That's because, after finding the thigh bone, 138 00:11:32,000 --> 00:11:37,000 they discover another huge bone from the front leg - a humerus. 139 00:11:43,000 --> 00:11:50,000 By measuring the circumference of each of these leg bones, 140 00:11:50,000 --> 00:11:51,000 Let's see how much. 141 00:12:07,000 --> 00:12:08,000 Yeah, around 70 tonnes or even more, probably. Wow! 142 00:12:08,000 --> 00:12:16,000 That's really big. 143 00:12:16,000 --> 00:12:22,000 That evening, Dr Jose Luis Carballido checks his calculations. 144 00:12:41,000 --> 00:12:46,000 Until now, Argentinosaurus was the heaviest known dinosaur. 145 00:12:46,000 --> 00:12:48,000 Ours already looks bigger. 146 00:12:57,000 --> 00:13:02,000 Could this mean it was the largest animal ever to walk the earth? 147 00:13:02,000 --> 00:13:04,000 Could it also be a new species? 148 00:13:04,000 --> 00:13:08,000 We can't be sure...yet. 149 00:13:23,000 --> 00:13:45,000 I've now come nearly 500 miles north 150 00:13:45,000 --> 00:13:50,000 to take a step without walking on a dinosaur eggshell. 151 00:14:01,000 --> 00:14:04,000 that once enclosed these fragments 152 00:14:04,000 --> 00:14:09,000 and they can tell us quite a lot about how titanosaurs reproduced. 153 00:14:11,000 --> 00:14:15,000 Careful excavation has shown that these dinosaurs 154 00:14:15,000 --> 00:14:19,000 laid eggs in clutches of up to 30 or 40 at a time. 155 00:14:19,000 --> 00:14:25,000 They would have looked rather like these replicas 156 00:14:25,000 --> 00:14:32,000 not covered by soil, but in a shallow depression. 157 00:14:32,000 --> 00:14:36,000 which suggests that the dinosaurs might have used rotting leaves 158 00:14:36,000 --> 00:14:38,000 to help with the incubation. 159 00:14:38,000 --> 00:14:42,000 The dinosaur that laid these eggs here were medium-sized. 160 00:14:42,000 --> 00:14:45,000 Our dinosaur that we're excavating, 161 00:14:45,000 --> 00:14:48,000 probably laid eggs as big as that. 162 00:14:50,000 --> 00:14:54,000 I'm shown around by Dr Luis Chiappe who, with his team, 163 00:14:54,000 --> 00:14:56,000 discovered this remarkable site. 164 00:14:57,000 --> 00:15:01,000 Dinosaur eggs here were laid on an old river plain. 165 00:15:03,000 --> 00:15:06,000 Then the river flooded and covered the unhatched eggs, 166 00:15:06,000 --> 00:15:08,000 preserving them in mud. 167 00:15:09,000 --> 00:15:12,000 You see, you know, many eggs... 168 00:15:12,000 --> 00:15:13,000 There. 169 00:15:13,000 --> 00:15:17,000 ..for kilometres and kilometres. Here's a nice one. 170 00:15:17,000 --> 00:15:19,000 Oh, that's a huge piece! Yup. 171 00:15:22,000 --> 00:15:25,000 And this is the actual surface of the egg? Yes. 172 00:15:25,000 --> 00:15:26,000 Astounding. 173 00:15:29,000 --> 00:15:32,000 Do you suppose they could have been coloured like birds' eggs? 174 00:15:32,000 --> 00:15:34,000 They may. Maybe they were off-white. 175 00:15:34,000 --> 00:15:37,000 We can't tell really. Yeah. 176 00:15:37,000 --> 00:15:40,000 Well, we can see all the tiny pores on the surface. 177 00:15:40,000 --> 00:15:41,000 And the texture. 178 00:15:41,000 --> 00:15:43,000 Yeah. What a beautiful piece. 179 00:15:43,000 --> 00:15:47,000 You must admit it's pretty romantic. 180 00:15:47,000 --> 00:15:48,000 THEY LAUGH 181 00:15:48,000 --> 00:15:50,000 I think it's incredible. 182 00:15:50,000 --> 00:15:51,000 I think it's absolutely extraordinary 183 00:15:51,000 --> 00:15:54,000 and I must put it back where I found it. 184 00:15:54,000 --> 00:15:55,000 Thank you. 185 00:15:58,000 --> 00:16:02,000 The fragments could tell us quite a lot about how the dinosaurs nested. 186 00:16:04,000 --> 00:16:07,000 But some, amazingly, can do even more than that. 187 00:16:12,000 --> 00:16:17,000 All these examples have something quite special. 188 00:16:17,000 --> 00:16:20,000 This one is my favourite. 189 00:16:20,000 --> 00:16:27,000 And what you can see is a very large patch of baby dinosaur skin. 190 00:16:29,000 --> 00:16:30,000 How wonderful! 191 00:16:30,000 --> 00:16:32,000 It's extraordinary. 192 00:16:32,000 --> 00:16:36,000 And this is not just an impression, this is the mineralised skin. It is. 193 00:16:36,000 --> 00:16:37,000 Yeah. 194 00:16:37,000 --> 00:16:39,000 Astounding. 195 00:16:39,000 --> 00:16:42,000 The eggs were not just preserving the bones, 196 00:16:42,000 --> 00:16:45,000 they were also preserving the skin of these babies. Yeah. 197 00:16:46,000 --> 00:16:48,000 This was just on the surface. 198 00:16:48,000 --> 00:16:52,000 I remember picking this up and brushing it a little bit 199 00:16:52,000 --> 00:16:54,000 and then using my hand lens 200 00:16:54,000 --> 00:17:00,000 and looking at this exact patch of skin and I realised that 201 00:17:00,000 --> 00:17:05,000 we had found something that no person had ever seen before. 202 00:17:05,000 --> 00:17:10,000 You are the first human being ever to see a baby dinosaur's skin. Yes. 203 00:17:10,000 --> 00:17:12,000 It was just an amazing... 204 00:17:12,000 --> 00:17:14,000 amazing moment. 205 00:17:14,000 --> 00:17:17,000 It must have been very close to hatching. 206 00:17:17,000 --> 00:17:21,000 It's almost complete, this thing. Yes, that's what we believe. 207 00:17:21,000 --> 00:17:23,000 And then a flood... 208 00:17:23,000 --> 00:17:24,000 Killed them all. 209 00:17:24,000 --> 00:17:28,000 Unfortunately for them, good for us. Yes. 210 00:17:30,000 --> 00:17:35,000 Luis Chiappe has dozens of complete eggs in his museum and 211 00:17:35,000 --> 00:17:39,000 he allows me to examine some of his most precious specimens for myself. 212 00:17:43,000 --> 00:17:46,000 There are many other remarkable things 213 00:17:46,000 --> 00:17:48,000 in these astonishing time capsules. 214 00:17:48,000 --> 00:17:52,000 This one has got, perfectly clearly, the limb bones. 215 00:17:55,000 --> 00:17:58,000 Here is a skull. 216 00:17:58,000 --> 00:18:00,000 That's the orbit of the eye, 217 00:18:00,000 --> 00:18:03,000 there's the lower jaw, there's the snout. 218 00:18:07,000 --> 00:18:09,000 This one also has a skull, 219 00:18:09,000 --> 00:18:15,000 but on the tip of the snout you can see a little spike which is like the 220 00:18:15,000 --> 00:18:20,000 egg tooth that a bird embryo has to help it crack itself out of a shell. 221 00:18:23,000 --> 00:18:27,000 And here is a replica of what the complete, 222 00:18:27,000 --> 00:18:30,000 un-crushed shell must have looked like. 223 00:18:33,000 --> 00:18:35,000 With all these details, 224 00:18:35,000 --> 00:18:39,000 it is possible to imagine how a baby titanosaur entered the world. 225 00:18:41,000 --> 00:18:42,000 BABY SQUEAKS 226 00:18:50,000 --> 00:18:54,000 To get an idea of how these youngsters might have lived, 227 00:18:54,000 --> 00:18:59,000 we can compare them with their closest living relatives - birds. 228 00:19:02,000 --> 00:19:05,000 Rather like baby ostriches, a young titanosaur 229 00:19:05,000 --> 00:19:10,000 would have been able to walk soon after hatching. 230 00:19:14,000 --> 00:19:17,000 They may well have gathered into groups to give some safety 231 00:19:17,000 --> 00:19:20,000 from predators, as young ostriches do. 232 00:19:33,000 --> 00:19:37,000 Microscopic analysis of dinosaur leg bones show rings, 233 00:19:37,000 --> 00:19:39,000 rather like tree rings, 234 00:19:39,000 --> 00:19:43,000 and these indicate that titanosaurs grew very swiftly 235 00:19:43,000 --> 00:19:45,000 early in their lives 236 00:19:45,000 --> 00:19:48,000 and they could have lived for some 50 years, 237 00:19:48,000 --> 00:19:50,000 plenty of time to become enormous. 238 00:19:52,000 --> 00:19:56,000 The team now has 150 bones of our titanosaur, 239 00:19:56,000 --> 00:19:59,000 enough to get an idea, not only of its weight, 240 00:19:59,000 --> 00:20:01,000 but also its height and length. 241 00:20:02,000 --> 00:20:05,000 Now, the plan is to build a life-size reproduction 242 00:20:05,000 --> 00:20:07,000 of the complete skeleton. 243 00:20:24,000 --> 00:20:28,000 It's a challenge to find a place big enough to house an animal that's 244 00:20:28,000 --> 00:20:32,000 four times longer than a London bus and nearly twice its height. 245 00:20:32,000 --> 00:20:37,000 But Diego thinks he's found one. It's an old wool warehouse. 246 00:20:41,000 --> 00:20:45,000 One, two, three, four, 247 00:20:45,000 --> 00:20:49,000 five, six, seven... 248 00:20:49,000 --> 00:20:52,000 We have been looking for a place that is big enough 249 00:20:52,000 --> 00:20:53,000 to fit our dinosaur. 250 00:20:57,000 --> 00:20:58,000 This seems to be it. 251 00:20:58,000 --> 00:21:00,000 This is a warehouse that we could use, 252 00:21:00,000 --> 00:21:04,000 not only in terms of the length, this is 70 metres long, 253 00:21:04,000 --> 00:21:06,000 but also it's very important in terms of the height. 254 00:21:06,000 --> 00:21:09,000 So we need a place not only long, but really high. 255 00:21:10,000 --> 00:21:13,000 It really needs a little bit of decoration, 256 00:21:13,000 --> 00:21:15,000 but I think it will do it. 257 00:21:15,000 --> 00:21:16,000 It's going to be awesome! 258 00:21:19,000 --> 00:21:22,000 Putting the skeleton together will help us 259 00:21:22,000 --> 00:21:25,000 understand the particular challenges of being such a giant. 260 00:21:31,000 --> 00:21:36,000 So, next, an international team of skeleton builders arrive 261 00:21:36,000 --> 00:21:41,000 to scan the bones ready to make a 3-D computer model of each of them. 262 00:21:48,000 --> 00:21:54,000 3-D scanning, accurate to 0.01 of a millimetre, 263 00:21:54,000 --> 00:21:58,000 allows images of the bones to be placed in a virtual reality world 264 00:21:58,000 --> 00:22:02,000 so that they can now be examined from all points of view 265 00:22:02,000 --> 00:22:05,000 without needing eight people to lift them. 266 00:22:08,000 --> 00:22:12,000 One of the mysteries surrounding our dinosaur is, 267 00:22:12,000 --> 00:22:15,000 how could an animal as big as it was actually move about? 268 00:22:19,000 --> 00:22:21,000 The computer data allows us 269 00:22:21,000 --> 00:22:24,000 to put our dinosaur leg bones together in 3-D 270 00:22:24,000 --> 00:22:29,000 and then compare the arrangement with what we know about living animals. 271 00:22:39,000 --> 00:22:43,000 Elephants are the largest land animal alive today. 272 00:22:47,000 --> 00:22:51,000 They, like titanosaurs, have to move their massive bodies around 273 00:22:51,000 --> 00:22:55,000 without their bones shattering under the enormous weight. 274 00:23:01,000 --> 00:23:05,000 I've come to meet Professor John Hutchinson 275 00:23:05,000 --> 00:23:07,000 here at ZSL Whipsnade Zoo. 276 00:23:08,000 --> 00:23:12,000 He's studied elephants for many years and has joined the team 277 00:23:12,000 --> 00:23:16,000 that's investigating the internal workings of our titanosaur. 278 00:23:16,000 --> 00:23:19,000 We have about a one-metre long pressure sensitive mat out there 279 00:23:19,000 --> 00:23:23,000 with several thousand sensors in it and it's telling us, in very 280 00:23:23,000 --> 00:23:27,000 high resolution, what the pressure on an elephant's foot is like. 281 00:23:28,000 --> 00:23:31,000 We can see on the elephant's foot here... 282 00:23:31,000 --> 00:23:33,000 Here she goes... Oh, yeah! Great. 283 00:23:33,000 --> 00:23:35,000 Oh, that was a perfect one! Bull's-eye! 284 00:23:36,000 --> 00:23:38,000 The pressure hits the ground, 285 00:23:38,000 --> 00:23:42,000 rolls over and then pushes off with its toenails. 286 00:23:43,000 --> 00:23:48,000 So we can see there some hot colours, or reds and oranges, 287 00:23:48,000 --> 00:23:52,000 on the toenails of Melvin's foot indicating high pressure. 288 00:23:52,000 --> 00:23:56,000 And then some cooler colours back towards the heel pad 289 00:23:56,000 --> 00:23:59,000 in the greens and light blue. 290 00:23:59,000 --> 00:24:00,000 That's low pressure. 291 00:24:00,000 --> 00:24:04,000 So elephants are supporting most of their weight on their toenails. 292 00:24:04,000 --> 00:24:08,000 That pressure gets transmitted up to their toe bones 293 00:24:08,000 --> 00:24:11,000 and then up to their wrists and ankles and so forth. 294 00:24:14,000 --> 00:24:18,000 John's analysis suggests that our titanosaur's legs, 295 00:24:18,000 --> 00:24:20,000 like those of an elephant, 296 00:24:20,000 --> 00:24:25,000 were placed vertically beneath the body like strong, massive columns. 297 00:24:28,000 --> 00:24:31,000 This arrangement transmits the weight to the toes 298 00:24:31,000 --> 00:24:36,000 and then spreads the force, using fatty pads in the back feet, 299 00:24:36,000 --> 00:24:38,000 as shock absorbers. 300 00:24:39,000 --> 00:24:43,000 But our titanosaur had one other adaptation to help them walk - 301 00:24:43,000 --> 00:24:45,000 one that elephants lack. 302 00:24:49,000 --> 00:24:53,000 A clue to this can be seen on the giant thighbone. 303 00:24:55,000 --> 00:24:57,000 How's it going? Good, good. 304 00:24:57,000 --> 00:25:01,000 Ben Garrod specialises in reconstructing skeletons 305 00:25:01,000 --> 00:25:04,000 and he's joining the team to look at the bones in detail. 306 00:25:06,000 --> 00:25:09,000 Marks on them show clearly where the muscles were attached. 307 00:25:11,000 --> 00:25:14,000 That's halfway down the femur, isn't it, that big lump there... Yes. 308 00:25:14,000 --> 00:25:16,000 ..for these massive muscle and, I guess, tendon attachments? 309 00:25:17,000 --> 00:25:22,000 This lump is where a huge muscle was attached to the femur. 310 00:25:23,000 --> 00:25:26,000 The other end of this muscle was connected to bones 311 00:25:26,000 --> 00:25:28,000 like these in the tail. 312 00:25:29,000 --> 00:25:32,000 It's this connection that helped our dinosaur to walk. 313 00:25:33,000 --> 00:25:36,000 They've got so much strength and so much rigidity up there. 314 00:25:36,000 --> 00:25:41,000 They actually used their tails to help move, to help their propulsion. 315 00:25:41,000 --> 00:25:45,000 So they had massive muscles and tendons from... Help...? 316 00:25:45,000 --> 00:25:48,000 Yes, so the movement of the tail actually pulled the hind legs 317 00:25:48,000 --> 00:25:50,000 backwards and then raised them forwards. 318 00:25:50,000 --> 00:25:51,000 Oh, I see. 319 00:25:52,000 --> 00:25:54,000 I must try that sometime! 320 00:25:54,000 --> 00:25:56,000 LAUGHTER 321 00:25:59,000 --> 00:26:03,000 The largest lizard alive today, the Komodo dragon, 322 00:26:03,000 --> 00:26:05,000 has a similar adaptation. 323 00:26:07,000 --> 00:26:11,000 The swing of their tail helps their back legs move more efficiently. 324 00:26:16,000 --> 00:26:18,000 Of course, our dinosaur was different, 325 00:26:18,000 --> 00:26:21,000 not least because it weighed over 500 times more. 326 00:26:23,000 --> 00:26:26,000 And that makes John Hutchinson suspect that it would have 327 00:26:26,000 --> 00:26:29,000 had to deal with another problem - 328 00:26:29,000 --> 00:26:32,000 one also faced by passengers on long-haul flights. 329 00:26:34,000 --> 00:26:38,000 Pressure in the legs of big animals is a really big problem. 330 00:26:38,000 --> 00:26:42,000 If blood stays down there too long, it's going to pool and clot. 331 00:26:43,000 --> 00:26:47,000 Much like airline socks that humans use, large animals, 332 00:26:47,000 --> 00:26:51,000 again and again, have evolved very thick elastic skin 333 00:26:51,000 --> 00:26:55,000 around their lower limb that helps to keep that pressure very high. 334 00:26:55,000 --> 00:26:57,000 Actually, I can empathise. 335 00:26:57,000 --> 00:27:01,000 I have to wear those same kind of stockings to get my blood 336 00:27:01,000 --> 00:27:02,000 back up my long legs! 337 00:27:04,000 --> 00:27:06,000 Time to thank our helpful elephant. 338 00:27:06,000 --> 00:27:08,000 You're a lovely thing. Yes, you... 339 00:27:08,000 --> 00:27:12,000 Oh, you want one! OK, in you go. 340 00:27:12,000 --> 00:27:14,000 Thanks. Thanks, pal. 341 00:27:16,000 --> 00:27:17,000 That's all I've got! 342 00:27:20,000 --> 00:27:24,000 A giant animal like an elephant also needs a huge heart to pump 343 00:27:24,000 --> 00:27:26,000 blood around its body. 344 00:27:26,000 --> 00:27:28,000 And so did our titanosaur. 345 00:27:44,000 --> 00:27:46,000 Its heart must have been immense. 346 00:27:50,000 --> 00:27:53,000 From our new, detailed knowledge of the skeleton, John Hutchinson 347 00:27:53,000 --> 00:27:57,000 has calculated that it was more than six feet in circumference. 348 00:28:04,000 --> 00:28:08,000 It probably weighed 230 kilos 349 00:28:08,000 --> 00:28:13,000 and would have had to shift 90 litres of blood with a single beat. 350 00:28:13,000 --> 00:28:14,000 There's one! 351 00:28:18,000 --> 00:28:22,000 And it would have had to repeat that beat every five seconds. 352 00:28:22,000 --> 00:28:23,000 HEART BEATS 353 00:28:23,000 --> 00:28:25,000 There it goes again. 354 00:28:29,000 --> 00:28:32,000 Weighing more than three grown men, 355 00:28:32,000 --> 00:28:34,000 it would have been extraordinarily powerful. 356 00:28:40,000 --> 00:28:44,000 And in order to pump blood around the body at high pressure 357 00:28:44,000 --> 00:28:49,000 and then into the delicate lungs at a lower pressure, 358 00:28:49,000 --> 00:28:54,000 it's thought that our titanosaur's heart had four chambers - 359 00:28:54,000 --> 00:28:56,000 more like that of a bird than a reptile. 360 00:29:01,000 --> 00:29:06,000 So, a powerful heart pumped the blood to the extremities of the body, 361 00:29:06,000 --> 00:29:08,000 but how did the blood get back? 362 00:29:12,000 --> 00:29:17,000 As in an elephant, a combination of fatty footpads 363 00:29:17,000 --> 00:29:21,000 and tight skin are thought to have forced the blood from its legs... 364 00:29:22,000 --> 00:29:24,000 ..all the way back to its heart. 365 00:29:39,000 --> 00:29:45,000 Toronto, Canada, and the world's biggest dinosaur-making factory. 366 00:29:53,000 --> 00:29:57,000 The team is building a life-size skeleton of this vast creature 367 00:29:57,000 --> 00:30:03,000 to be unveiled in Diego's warehouse in Argentina in six months' time. 368 00:30:06,000 --> 00:30:10,000 First, they have to turn all the information from the 3-D scans 369 00:30:10,000 --> 00:30:12,000 into each individual bone. 370 00:30:16,000 --> 00:30:19,000 State-of-the-art robots carve moulds from polystyrene 371 00:30:19,000 --> 00:30:22,000 so that the bones can be cast in fibreglass. 372 00:30:38,000 --> 00:30:43,000 Up until now, the fossil bones have been the main focus of the dig 373 00:30:43,000 --> 00:30:45,000 but the rock that surrounds the fossils 374 00:30:45,000 --> 00:30:48,000 also holds important information. 375 00:30:48,000 --> 00:30:53,000 The nature of the layers of rock in which these fossils lie can tell us 376 00:30:53,000 --> 00:30:58,000 a great deal about how they got to be where they are and how old they are. 377 00:30:59,000 --> 00:31:03,000 Some of these layers are volcanic ash which must have come 378 00:31:03,000 --> 00:31:07,000 from a volcano erupting every now and then somewhere in the neighbourhood. 379 00:31:12,000 --> 00:31:17,000 And this ash around the bones can tell us how old the fossils are. 380 00:31:18,000 --> 00:31:21,000 Scientists worked out that all these fossils 381 00:31:21,000 --> 00:31:24,000 dated from the Cretaceous period 382 00:31:24,000 --> 00:31:25,000 but better than that, 383 00:31:25,000 --> 00:31:33,000 they dated them precisely to 101.6 million years old. 384 00:31:40,000 --> 00:31:43,000 By a detailed forensic examination 385 00:31:43,000 --> 00:31:46,000 and comparisons with living creatures, 386 00:31:46,000 --> 00:31:51,000 the team have deduced a great deal about the life of our titanosaur. 387 00:31:55,000 --> 00:32:00,000 We now know when it lived, how big it was, 388 00:32:00,000 --> 00:32:04,000 how it moved and what its young might have looked like. 389 00:32:04,000 --> 00:32:07,000 We've even calculated its heart rate. 390 00:32:15,000 --> 00:32:19,000 In an investigation of this scale, sometimes the most important 391 00:32:19,000 --> 00:32:22,000 information comes not from the most eye-catching evidence 392 00:32:22,000 --> 00:32:25,000 but from quite tiny details. 393 00:32:29,000 --> 00:32:35,000 Here is something that I really hoped the excavation was going to find. 394 00:32:38,000 --> 00:32:39,000 It's a tooth. 395 00:32:41,000 --> 00:32:45,000 And it's tiny compared with the size of the huge animals 396 00:32:45,000 --> 00:32:47,000 from which it came. 397 00:32:48,000 --> 00:32:53,000 Teeth can tell you a huge amount about an animal. 398 00:32:53,000 --> 00:32:57,000 And if you look at the tip, you can see that it has been 399 00:32:57,000 --> 00:33:01,000 worn into two facets on either side. 400 00:33:01,000 --> 00:33:06,000 And that tells us that this tooth engaged with the teeth on the other 401 00:33:06,000 --> 00:33:12,000 side in an alternate way like that, not head-on but one on either side. 402 00:33:12,000 --> 00:33:15,000 So this animal, like a pair of scissors, 403 00:33:15,000 --> 00:33:19,000 just nipped off the vegetation on which it was feeding. 404 00:33:19,000 --> 00:33:24,000 Enormous though it was, just nipped off little leaves 405 00:33:24,000 --> 00:33:26,000 and here are fossils 406 00:33:26,000 --> 00:33:30,000 of some of the different kinds of plants on which it might have fed... 407 00:33:31,000 --> 00:33:36,000 ..cycads, ferns and conifers. 408 00:33:45,000 --> 00:33:48,000 One thing these plants have in common 409 00:33:48,000 --> 00:33:52,000 is that they're all very fibrous and hard to digest. 410 00:33:53,000 --> 00:33:57,000 To get enough nutrients from such poor quality foods 411 00:33:57,000 --> 00:34:01,000 our titanosaur would have had to eat them in vast quantities. 412 00:34:05,000 --> 00:34:09,000 A descendent of one of these plants still grows in Patagonia today. 413 00:34:13,000 --> 00:34:18,000 200 million years ago when South America, Australia 414 00:34:18,000 --> 00:34:21,000 and Antarctica were all joined together to form 415 00:34:21,000 --> 00:34:24,000 a supercontinent called Gondwana, 416 00:34:24,000 --> 00:34:27,000 a particular kind of vegetation was dominant - 417 00:34:27,000 --> 00:34:28,000 they were conifers. 418 00:34:30,000 --> 00:34:33,000 They continued to survive to 100 million years ago 419 00:34:33,000 --> 00:34:37,000 when our titanosaurs were roaming the land and a few still 420 00:34:37,000 --> 00:34:43,000 survive today. Here in the foothills of the Andes is one of them. 421 00:34:43,000 --> 00:34:46,000 The monkey puzzle tree called araucaria. 422 00:34:51,000 --> 00:34:54,000 Trees, like araucaria, show that the dinosaurs 423 00:34:54,000 --> 00:34:56,000 must have had another problem. 424 00:34:58,000 --> 00:35:01,000 These conifers, apart from being poor-quality fodder, 425 00:35:01,000 --> 00:35:05,000 can grow to over 130 feet in height. 426 00:35:07,000 --> 00:35:12,000 They would have been out of reach for many animals but not our titanosaur. 427 00:35:17,000 --> 00:35:18,000 Here, boys, come on. 428 00:35:22,000 --> 00:35:28,000 It's pretty clear why a long neck is useful for a land-living animal. 429 00:35:29,000 --> 00:35:33,000 It enables it to reach vegetation which is growing high up 430 00:35:33,000 --> 00:35:38,000 at the top trees that other ground-based animals couldn't reach 431 00:35:38,000 --> 00:35:42,000 and it must have been much the same for titanosaur, 432 00:35:42,000 --> 00:35:45,000 except we know from the fossils that titanosaur's neck was 433 00:35:45,000 --> 00:35:47,000 very, very much longer. 434 00:35:49,000 --> 00:35:54,000 And that enabled it to sweep its head in a great wide arc 435 00:35:54,000 --> 00:35:58,000 and even to reach between two tree trunks that happened to be 436 00:35:58,000 --> 00:36:01,000 growing close together to get other vegetation. 437 00:36:01,000 --> 00:36:02,000 What about that? 438 00:36:06,000 --> 00:36:10,000 This enormous reach would have saved our titanosaur a lot of energy. 439 00:36:11,000 --> 00:36:15,000 It only needed to move its neck to feed, not its whole body. 440 00:36:18,000 --> 00:36:22,000 But how did it eat enough of this poor-quality food to survive? 441 00:36:24,000 --> 00:36:26,000 Elephants face a similar challenge today. 442 00:36:28,000 --> 00:36:32,000 An elephant can collect and chew about 130 kilos - 443 00:36:32,000 --> 00:36:36,000 that's 300 pounds of vegetation in a day. 444 00:36:37,000 --> 00:36:41,000 But our titanosaur could have eaten five times that amount. 445 00:36:43,000 --> 00:36:46,000 It's been estimated that a large titanosaur would eat enough 446 00:36:46,000 --> 00:36:49,000 plant material to fill a skip in a single day. 447 00:36:51,000 --> 00:36:53,000 So how did they digest it all? 448 00:36:54,000 --> 00:36:56,000 Elephants solved the problem by giving their food 449 00:36:56,000 --> 00:37:01,000 long preparatory chews but titanosaurs didn't bother. 450 00:37:03,000 --> 00:37:06,000 They simply gathered leaves by nipping them off 451 00:37:06,000 --> 00:37:08,000 and then swallowing them whole. 452 00:37:10,000 --> 00:37:13,000 But that in turn would mean that they needed a bigger 453 00:37:13,000 --> 00:37:17,000 and longer gut to digest all that unchewed food. 454 00:37:19,000 --> 00:37:21,000 And it might well have taken ten days 455 00:37:21,000 --> 00:37:23,000 for food to pass through their system. 456 00:37:25,000 --> 00:37:32,000 A bigger gut needs a bigger body so titanosaurs grew bigger and bigger 457 00:37:32,000 --> 00:37:35,000 until they approached the limits of what their bones could support. 458 00:37:45,000 --> 00:37:50,000 Two years after the dig began, a strange cargo arrives, 459 00:37:50,000 --> 00:37:53,000 having made a 7,000 mile journey from Canada. 460 00:38:01,000 --> 00:38:03,000 Dozens of packing cases later 461 00:38:03,000 --> 00:38:07,000 and all the bones are finally in Diego's warehouse. 462 00:38:16,000 --> 00:38:19,000 Assembling the skeleton can finally begin. 463 00:38:22,000 --> 00:38:26,000 The 3-D data used to make the skeleton has also been used 464 00:38:26,000 --> 00:38:28,000 to create a computer model. 465 00:38:30,000 --> 00:38:32,000 It means I can get a preview 466 00:38:32,000 --> 00:38:34,000 of what the final skeleton will look like. 467 00:38:34,000 --> 00:38:38,000 The first thing is these very, very lovely legs. 468 00:38:38,000 --> 00:38:40,000 If we turn it around, they are very, very column-like 469 00:38:40,000 --> 00:38:41,000 and this is like elephants 470 00:38:41,000 --> 00:38:46,000 but interestingly this titanosaur had slightly splayed legs, 471 00:38:46,000 --> 00:38:50,000 at an angle of about five degrees and this slight change would have 472 00:38:50,000 --> 00:38:54,000 really increased the ability to take all that extra weight. 473 00:38:54,000 --> 00:38:56,000 Can you see the splay because of the joint or 474 00:38:56,000 --> 00:38:59,000 because of the shape of the bone? A bit of both. 475 00:38:59,000 --> 00:39:01,000 You can tell from the shape of the bone and from where certain 476 00:39:01,000 --> 00:39:05,000 parts of the bones form and how they sit and then how the bones fit 477 00:39:05,000 --> 00:39:08,000 with one another you can really tell how it would have sat in real life. 478 00:39:08,000 --> 00:39:11,000 Another thing you can see is a very, very long neck. 479 00:39:11,000 --> 00:39:15,000 And we just found out that ours had 15 bones in its neck. 480 00:39:15,000 --> 00:39:19,000 Interestingly, some of them were five or six times longer than 481 00:39:19,000 --> 00:39:20,000 they were wide. 482 00:39:20,000 --> 00:39:22,000 These incredibly long vertebrae and there's lots of them. 483 00:39:22,000 --> 00:39:25,000 Why does it have such a long tail? 484 00:39:25,000 --> 00:39:28,000 Well, a couple of reasons. If you've got an animal this big with 485 00:39:28,000 --> 00:39:31,000 a neck this long, the last thing you want to be is top-heavy. 486 00:39:31,000 --> 00:39:35,000 And research has just shown that the centre of gravity 487 00:39:35,000 --> 00:39:39,000 in this animal was somewhere right in the middle of the chest cavity. 488 00:39:40,000 --> 00:39:46,000 So the heavy tail counterbalances the exceedingly long neck. 489 00:39:46,000 --> 00:39:49,000 But judging from the size of the muscle attachments, 490 00:39:49,000 --> 00:39:51,000 the tail was also immensely strong. 491 00:39:53,000 --> 00:39:58,000 It had huge muscles from around here right down to about a third 492 00:39:58,000 --> 00:40:00,000 of the way down the tail, somewhere around here. 493 00:40:00,000 --> 00:40:04,000 So that would be solid flesh? Yep, muscle tissue, other tissue, 494 00:40:04,000 --> 00:40:05,000 ligaments, tendons. 495 00:40:05,000 --> 00:40:07,000 Do you think they might have fought with it? 496 00:40:07,000 --> 00:40:09,000 Possibly. Thrashing it about? 497 00:40:09,000 --> 00:40:11,000 It could've been used as a defence mechanism 498 00:40:11,000 --> 00:40:14,000 so you're walking up to that as a predator, the last thing you 499 00:40:14,000 --> 00:40:16,000 want to be is on the receiving end. Don't put me into it! 500 00:40:20,000 --> 00:40:21,000 Yeah. 501 00:40:30,000 --> 00:40:36,000 The long and painstaking examination of the backbone has now borne fruit 502 00:40:36,000 --> 00:40:38,000 and Ben has got some important news. 503 00:40:44,000 --> 00:40:47,000 This is a vertebrae here from right high up in the back, 504 00:40:47,000 --> 00:40:49,000 right near the shoulder blades. 505 00:40:49,000 --> 00:40:54,000 And the most important thing is this little ridge that ends in this 506 00:40:54,000 --> 00:40:57,000 big lump and this is only found in this particular dinosaur 507 00:40:57,000 --> 00:41:01,000 so from that and a few other physical differences, 508 00:41:01,000 --> 00:41:04,000 we think we have got a brand-new, exciting species. 509 00:41:06,000 --> 00:41:10,000 So our titanosaur is not only a giant, 510 00:41:10,000 --> 00:41:13,000 it is indeed a new species of dinosaur. 511 00:41:15,000 --> 00:41:20,000 Examining the spinal bones also reveal something about how it coped 512 00:41:20,000 --> 00:41:22,000 with life as a giant. 513 00:41:24,000 --> 00:41:28,000 This is where the spinal cord would have passed. 514 00:41:29,000 --> 00:41:32,000 So this hole straight through here? Mm-hm. 515 00:41:32,000 --> 00:41:34,000 The whole nerve centre, as it were, 516 00:41:34,000 --> 00:41:37,000 the cable carrying all the nerves. From the base of the tail 517 00:41:37,000 --> 00:41:41,000 right to the skull. It's very small. It is, yeah. Ours is what? 518 00:41:41,000 --> 00:41:44,000 About thumb width. So it's not all that much bigger. No. 519 00:41:46,000 --> 00:41:49,000 This cord was well over 100 feet long. 520 00:41:52,000 --> 00:41:55,000 It would have taken about a second for a nerve impulse 521 00:41:55,000 --> 00:41:58,000 to go from its tail to its brain. 522 00:41:59,000 --> 00:42:03,000 And what's more, the spine has revealed another surprise. 523 00:42:04,000 --> 00:42:07,000 It is full of holes, rather like a Swiss cheese. 524 00:42:10,000 --> 00:42:14,000 The neck bones of titanosaurs contain so many holes 525 00:42:14,000 --> 00:42:18,000 and spaces that they weighed around 35% less than 526 00:42:18,000 --> 00:42:22,000 they would have done had they been made of solid bone. 527 00:42:22,000 --> 00:42:26,000 The leg bones of modern birds are much the same. 528 00:42:26,000 --> 00:42:30,000 And those spaces serve another very important function. 529 00:42:30,000 --> 00:42:32,000 They contained air sacs. 530 00:42:35,000 --> 00:42:39,000 These air sacs were connected with the lungs. 531 00:42:43,000 --> 00:42:46,000 So what was their function and how did they work? 532 00:42:46,000 --> 00:42:50,000 They occupied much of the chest and ran along the whole length 533 00:42:50,000 --> 00:42:53,000 of the body along the backbone 534 00:42:53,000 --> 00:42:57,000 to the 17-metre-long neck and then to the head. 535 00:43:00,000 --> 00:43:04,000 It's thought the balloon-like sacs had thin but strong membranes. 536 00:43:07,000 --> 00:43:12,000 These sacs acted like bellows, forcing air into the lungs. 537 00:43:14,000 --> 00:43:19,000 When we breathe in, air flows down into our lungs, 538 00:43:19,000 --> 00:43:23,000 oxygen is absorbed in exchange for carbon dioxide which is then 539 00:43:23,000 --> 00:43:26,000 got rid of when we breathe out. 540 00:43:26,000 --> 00:43:31,000 The air sac system is very much more complex but very much more efficient. 541 00:43:33,000 --> 00:43:38,000 It enabled a titanosaur to take in oxygen continuously, 542 00:43:38,000 --> 00:43:41,000 not just when breathing in but also when breathing out. 543 00:44:06,000 --> 00:44:10,000 Our titanosaur wasn't the only giant living around here. 544 00:44:10,000 --> 00:44:11,000 ROARING 545 00:44:15,000 --> 00:44:21,000 This was a dangerous world, where meat-eaters were giants too. 546 00:44:25,000 --> 00:44:29,000 New evidence from the dig site shows that carnivorous dinosaurs 547 00:44:29,000 --> 00:44:31,000 were here as well. 548 00:44:34,000 --> 00:44:40,000 So these are some of the over 80 teeth we found on the dig site. 549 00:44:40,000 --> 00:44:44,000 And you can feel how sharp they are. 550 00:44:46,000 --> 00:44:50,000 Oh, yes, it's serrated, just like a shark's tooth, in fact. Absolutely. 551 00:44:50,000 --> 00:44:55,000 They actually belong to a family known as a shark-toothed dinosaurs. 552 00:44:55,000 --> 00:44:58,000 We can identify the teeth at the family level. 553 00:44:58,000 --> 00:45:01,000 We know of one species that belonged to that family, 554 00:45:01,000 --> 00:45:05,000 it's called Tyrannotitan chubutensis. 555 00:45:05,000 --> 00:45:06,000 Tyrannotitan? Yeah. 556 00:45:06,000 --> 00:45:12,000 That means a ferocious giant, ferocious beast. Exactly. Good name. 557 00:45:12,000 --> 00:45:15,000 Yeah. Chubutensis is because of the area it comes from? 558 00:45:15,000 --> 00:45:17,000 Yes, this is the Chubut province. 559 00:45:17,000 --> 00:45:18,000 Great. 560 00:45:19,000 --> 00:45:24,000 Tyrannotitan must have been a ferocious-looking beast. 561 00:45:25,000 --> 00:45:28,000 With large eyes, sharp, flesh-eating teeth... 562 00:45:30,000 --> 00:45:36,000 ..and strong legs, it was a fast, alert, meat-eating dinosaur. 563 00:45:40,000 --> 00:45:44,000 And it was as big as T Rex. Really? Not as famous. 564 00:45:44,000 --> 00:45:47,000 Not as famous. Tell that to Hollywood. 565 00:45:47,000 --> 00:45:50,000 I have some bones over there I would like to show you. 566 00:45:52,000 --> 00:45:57,000 So this is one of the tail vertebrae we found at the dig site. 567 00:45:57,000 --> 00:46:00,000 There's something really interesting here. 568 00:46:00,000 --> 00:46:01,000 You can see this groove? Mmm. 569 00:46:01,000 --> 00:46:05,000 Well, this groove was probably a bite mark 570 00:46:05,000 --> 00:46:07,000 made by one of the carnivores. By one of these teeth? 571 00:46:07,000 --> 00:46:10,000 Right. So it was... What do you mean? Like that? 572 00:46:10,000 --> 00:46:15,000 Exactly. Taking the flesh out of their tail. Really? Yeah. 573 00:46:16,000 --> 00:46:17,000 The tender bits. 574 00:46:19,000 --> 00:46:22,000 They would be too. Yeah, absolutely. 575 00:46:22,000 --> 00:46:26,000 Can you determine whether it was a scavenger or it was a hunter? 576 00:46:26,000 --> 00:46:29,000 We don't know if they were dead, I mean, they were scavenging 577 00:46:29,000 --> 00:46:33,000 on the carcasses, or if they were actually hunting and killing them. 578 00:46:34,000 --> 00:46:39,000 Well, it didn't make much difference to the old dinosaur. Yes. 579 00:46:41,000 --> 00:46:44,000 In a detective story, to close the case, 580 00:46:44,000 --> 00:46:47,000 you really want to know how the victim met its end. 581 00:46:49,000 --> 00:46:53,000 If our titanosaur didn't perish in the jaws of a Tyrannotitan, 582 00:46:53,000 --> 00:46:54,000 how did it die? 583 00:46:58,000 --> 00:47:02,000 Clues can be found by the detailed three-dimensional mapping 584 00:47:02,000 --> 00:47:06,000 of the location of every fossil bone, small and large. 585 00:47:09,000 --> 00:47:14,000 That shows that the dig site contains the remains of not just one 586 00:47:14,000 --> 00:47:16,000 but seven different individuals. 587 00:47:18,000 --> 00:47:19,000 All of the new species. 588 00:47:20,000 --> 00:47:25,000 And the first thing to notice is that they are on three different levels. 589 00:47:29,000 --> 00:47:31,000 That's to say the animals must have come here 590 00:47:31,000 --> 00:47:34,000 on at least three different occasions. 591 00:47:40,000 --> 00:47:42,000 But why should they have done that? 592 00:47:51,000 --> 00:47:55,000 There are several theories as to why seven bodies 593 00:47:55,000 --> 00:47:59,000 should have all ended up at this one particular place. 594 00:47:59,000 --> 00:48:02,000 The first is that this was a seasonal climate 595 00:48:02,000 --> 00:48:04,000 and that as the dry season proceeded 596 00:48:04,000 --> 00:48:08,000 this was one of the last remaining pools of water 597 00:48:08,000 --> 00:48:12,000 and when this went, the sauropods that happened to be here died here. 598 00:48:15,000 --> 00:48:21,000 The second is that these bodies were swept down by great rivers 599 00:48:21,000 --> 00:48:25,000 during the rainy season and then where the land levelled out, 600 00:48:25,000 --> 00:48:27,000 so those bodies were dumped. 601 00:48:28,000 --> 00:48:32,000 Analysis of the sediments around the bones shows that there were rivers 602 00:48:32,000 --> 00:48:36,000 gently flowing across this site at the time of their death. 603 00:48:41,000 --> 00:48:44,000 There was no shortage of water to drink. 604 00:48:45,000 --> 00:48:48,000 What's more the rivers were not moving fast enough 605 00:48:48,000 --> 00:48:49,000 to shift such huge bodies. 606 00:48:51,000 --> 00:48:54,000 So the corpses weren't washed here by floodwaters either. 607 00:48:57,000 --> 00:49:00,000 Could there be another reason why they all died in one 608 00:49:00,000 --> 00:49:03,000 place on three different occasions? 609 00:49:05,000 --> 00:49:09,000 We know from layers of ash around the bones that there were 610 00:49:09,000 --> 00:49:12,000 volcanoes erupting in the neighbourhood 611 00:49:12,000 --> 00:49:15,000 so doubtless there were areas where the ground was 612 00:49:15,000 --> 00:49:20,000 warmed by volcanic fumes, just as they are here today. 613 00:49:20,000 --> 00:49:24,000 We also know that dinosaurs regularly laid their eggs in such places, 614 00:49:24,000 --> 00:49:28,000 doubtless taking advantage of the volcanic warmth to help 615 00:49:28,000 --> 00:49:29,000 incubate their eggs. 616 00:49:29,000 --> 00:49:33,000 So maybe that was the reason why they kept returning to the same place. 617 00:49:40,000 --> 00:49:44,000 Certainly the excavation of the dinosaur egg site 618 00:49:44,000 --> 00:49:46,000 seems to support this. 619 00:49:48,000 --> 00:49:50,000 Nests like these have been found 620 00:49:50,000 --> 00:49:55,000 at four quite widely separated layers in the rocks, 621 00:49:55,000 --> 00:50:00,000 showing that dinosaurs came back to this particular site again 622 00:50:00,000 --> 00:50:03,000 and again and again over a long period of time. 623 00:50:13,000 --> 00:50:18,000 Ash from a volcanic eruption can sometimes fall in such quantities 624 00:50:18,000 --> 00:50:22,000 that the whole vegetation is blanketed by it and killed. 625 00:50:23,000 --> 00:50:26,000 So life in the aftermath of a big eruption 626 00:50:26,000 --> 00:50:28,000 can be very difficult for a plant-eater. 627 00:50:31,000 --> 00:50:36,000 Whatever the explanation, individuals over several generations came 628 00:50:36,000 --> 00:50:39,000 to this one place and died here. 629 00:50:42,000 --> 00:50:43,000 The dig is coming to an end 630 00:50:43,000 --> 00:50:48,000 and the team have assembled a record-breaking number of bones 631 00:50:48,000 --> 00:50:53,000 but they're still hoping to find one last piece of the puzzle - the skull. 632 00:50:53,000 --> 00:50:59,000 So what number's this, 203? Actually this is 223. 23? 633 00:50:59,000 --> 00:51:01,000 Between the seven individuals? 634 00:51:01,000 --> 00:51:03,000 Yeah. Between all the seven individuals we found 635 00:51:03,000 --> 00:51:05,000 here on this site. 636 00:51:05,000 --> 00:51:08,000 If these are neck vertebrae, could they be leading towards a skull? 637 00:51:08,000 --> 00:51:10,000 Yes, that's what were hoping for. 638 00:51:10,000 --> 00:51:13,000 We just found another neck vertebrae over there. 639 00:51:13,000 --> 00:51:16,000 That would be a great triumph if you found a skull, wouldn't it? 640 00:51:16,000 --> 00:51:20,000 There are only three titanosaur skulls known so far. Really? Yeah. 641 00:51:20,000 --> 00:51:23,000 So they're very rare. And that's because they're very fragile. 642 00:51:23,000 --> 00:51:25,000 They're very delicate bones 643 00:51:25,000 --> 00:51:30,000 and they have very light sutures between each of the bones. 644 00:51:30,000 --> 00:51:35,000 OK, well, let's hope you find number four. Yeah. Could be under there. 645 00:51:35,000 --> 00:51:38,000 Could be. We're going for that. Wonderful. 646 00:51:42,000 --> 00:51:44,000 Alas, it was not to be. 647 00:51:49,000 --> 00:51:52,000 So I gather you haven't yet found the skull. Sadly not. 648 00:51:52,000 --> 00:51:56,000 The only thing we have found out of the skull is his tooth. 649 00:51:59,000 --> 00:52:03,000 So to complete the skeleton, the team have to reconstruct one... 650 00:52:03,000 --> 00:52:05,000 Take that piece out of there. 651 00:52:05,000 --> 00:52:09,000 ..basing it on the three skulls of other titanosaur species 652 00:52:09,000 --> 00:52:12,000 to produce one which most suits the single tooth that we have. 653 00:52:20,000 --> 00:52:26,000 The scientific team has discovered, collected, cleaned, 654 00:52:26,000 --> 00:52:31,000 scanned and copied 220 bones of our giant. 655 00:52:31,000 --> 00:52:36,000 Soon it'll be possible to put those copies together to get some idea 656 00:52:36,000 --> 00:52:39,000 of what the living animal actually looked like. 657 00:52:40,000 --> 00:52:44,000 But the fossil bones themselves still have many secrets 658 00:52:44,000 --> 00:52:46,000 that are waiting to be revealed. 659 00:52:55,000 --> 00:52:59,000 All the theory can now be put to the test. 660 00:53:04,000 --> 00:53:08,000 We can finally get the most accurate estimate of our dinosaur's weight 661 00:53:08,000 --> 00:53:10,000 and true size. 662 00:53:24,000 --> 00:53:29,000 It takes two weeks, working day and night, to fit all the bones together. 663 00:53:45,000 --> 00:53:48,000 Wow! God! 664 00:53:51,000 --> 00:53:54,000 Absolutely amazing! 665 00:54:14,000 --> 00:54:15,000 Good gracious! 666 00:54:43,000 --> 00:54:48,000 Well, Diego, are you pleased with it? Yes, we are very pleased. 667 00:54:48,000 --> 00:54:53,000 It is been a lot of work, it has taken 40,000 man-hours to get here 668 00:54:53,000 --> 00:54:56,000 but we're really, really happy with it. 669 00:54:56,000 --> 00:54:59,000 And does it answer some of your questions about the animal? 670 00:54:59,000 --> 00:55:00,000 Oh, yeah, absolutely. 671 00:55:00,000 --> 00:55:02,000 It answers a lot of questions 672 00:55:02,000 --> 00:55:05,000 but the good thing is it raises more questions. 673 00:55:05,000 --> 00:55:09,000 So we have a lot of research to continue on this animal. 674 00:55:09,000 --> 00:55:12,000 It's clear that this thing still wasn't fully grown. 675 00:55:12,000 --> 00:55:14,000 It's massive, but it still had room to go. 676 00:55:14,000 --> 00:55:16,000 You mean the structure of the bones looks as 677 00:55:16,000 --> 00:55:18,000 though they were still growing? Yeah. 678 00:55:18,000 --> 00:55:24,000 So, that raises the really big question, is it the biggest 679 00:55:24,000 --> 00:55:26,000 so far discovered? 680 00:55:26,000 --> 00:55:28,000 Well, according to our estimate, 681 00:55:28,000 --> 00:55:31,000 this animal weighed 70 metric tonnes. 682 00:55:32,000 --> 00:55:36,000 70 metric tonnes. What would that compare with? 683 00:55:36,000 --> 00:55:41,000 That is like 15 African elephants. 15 African elephants? 684 00:55:41,000 --> 00:55:47,000 We are now sure that this animal was 10% larger than Argentinosaurus. 685 00:55:47,000 --> 00:55:49,000 The previous record-holder? 686 00:55:49,000 --> 00:55:51,000 The previous record-holder. So, yes, 687 00:55:51,000 --> 00:55:56,000 we think we have the largest dinosaur ever known. Fantastic! 688 00:55:56,000 --> 00:55:59,000 I can quite believe it. 689 00:55:59,000 --> 00:56:04,000 Congratulations to you. Thank you. Congratulations to he, she or it. 690 00:56:04,000 --> 00:56:06,000 Wonderful! A marvellous, marvellous thing! 691 00:56:25,000 --> 00:56:28,000 Piecing this complex jigsaw puzzle together 692 00:56:28,000 --> 00:56:30,000 has been a fascinating adventure. 693 00:56:33,000 --> 00:56:37,000 It all started with the discovery of one enormous thighbone. 694 00:56:38,000 --> 00:56:43,000 And then a team of 40 worked for over two years to excavate 695 00:56:43,000 --> 00:56:46,000 and put together the near-complete skeleton 696 00:56:46,000 --> 00:56:49,000 of the largest land animal yet discovered. 697 00:56:50,000 --> 00:56:53,000 And so added one further marvel 698 00:56:53,000 --> 00:56:57,000 to the astonishing history of life on earth. 699 00:57:05,000 --> 00:57:09,000 What a thrill it must have been to see it when it was alive. 700 00:57:12,000 --> 00:57:13,000 DEEP BREATHING 701 00:57:23,000 --> 00:57:26,000 RUMBLING 702 00:57:41,000 --> 00:57:42,000 RUMBLING 703 00:57:49,000 --> 00:57:50,000 TITANOSAUR ROARS 704 00:58:30,000 --> 00:58:32,000 500 Words is back - the Radio 2 writing competition for kids 705 00:58:32,000 --> 00:58:35,000 with our new judge, the Duchess of Cornwall! 706 00:58:35,000 --> 00:58:37,000 And the final will be held at Shakespeare's Globe.