1 00:00:16,517 --> 00:00:21,563 Surely, one of the most remarkable animals that has ever existed, 2 00:00:22,105 --> 00:00:26,318 and certainly one of the most famous, is a dinosaur. 3 00:00:27,361 --> 00:00:29,613 Tyrannosaurus rex. 4 00:00:30,656 --> 00:00:35,202 An animal to spark the imagination for all of us. 5 00:00:35,285 --> 00:00:38,247 What kind of an animal was it? 6 00:00:38,330 --> 00:00:41,542 What did it look like? How did it live? 7 00:00:41,625 --> 00:00:45,587 Now, scientific research has answered such questions. 8 00:00:45,671 --> 00:00:47,923 And not just about T. rex, 9 00:00:48,006 --> 00:00:51,343 but the other species that lived alongside it. 10 00:00:51,426 --> 00:00:58,016 And the latest imaging technology enables us to bring them all to life. 11 00:01:01,436 --> 00:01:05,440 Planet Earth, 66 million years ago. 12 00:01:13,949 --> 00:01:17,494 The skies are filled with flying giants. 13 00:01:20,038 --> 00:01:24,084 In the seas, monstrous reptiles patrol the depths. 14 00:01:26,128 --> 00:01:29,256 And on land, dinosaurs of every kind, 15 00:01:30,465 --> 00:01:33,218 all facing the struggle to survive. 16 00:01:39,391 --> 00:01:45,689 We now know so much about a world that was ruled by the dinosaurs. 17 00:01:49,651 --> 00:01:52,196 This is their story. 18 00:02:16,470 --> 00:02:19,556 For millions of years, the lands of planet Earth 19 00:02:19,640 --> 00:02:21,433 have been carved by water. 20 00:02:22,518 --> 00:02:26,772 And the rivers that flow here are still shaping these great canyons. 21 00:02:32,319 --> 00:02:36,365 Such places are the home of flying reptiles. 22 00:02:40,536 --> 00:02:41,703 Pterosaurs. 23 00:02:47,876 --> 00:02:52,548 Their wings of skin stretch from finger to ankle. 24 00:02:58,971 --> 00:03:02,766 And they can fly for hundreds of miles in a day. 25 00:03:38,510 --> 00:03:39,511 Each evening, 26 00:03:39,595 --> 00:03:45,350 they come to this canyon in huge numbers to roost on its narrow ledges. 27 00:03:49,605 --> 00:03:51,648 There is safety in numbers. 28 00:03:54,693 --> 00:03:58,071 And anyway, few land-living hunters venture here. 29 00:04:01,116 --> 00:04:02,701 But one does. 30 00:04:08,040 --> 00:04:11,210 A type of dinosaur. Velociraptor. 31 00:04:14,546 --> 00:04:18,175 Their bodies are kept warm by feathers, but they can't fly. 32 00:04:19,885 --> 00:04:23,055 They are, however, exceptionally agile. 33 00:04:31,313 --> 00:04:32,481 And just as well. 34 00:04:34,900 --> 00:04:37,903 One false step here could bring disaster. 35 00:04:44,910 --> 00:04:47,079 The pterosaurs are skittish. 36 00:04:47,162 --> 00:04:50,332 They will take to the air at the first sign of danger. 37 00:04:55,420 --> 00:05:01,051 If the Velociraptors are to get a meal, the element of surprise will be crucial. 38 00:05:21,280 --> 00:05:24,199 Lightweight bodies and feathered arms help them 39 00:05:24,283 --> 00:05:25,993 to control their descent. 40 00:05:31,623 --> 00:05:36,044 And their broad tails assist them in keeping their balance. 41 00:05:45,179 --> 00:05:47,848 Those pterosaurs that are resting on the margins 42 00:05:47,931 --> 00:05:50,809 of the colony will be the easiest targets. 43 00:06:23,091 --> 00:06:27,846 The roar of the waterfall drowns the sound of slipping rocks. 44 00:06:50,953 --> 00:06:53,205 The female goes high. 45 00:06:55,749 --> 00:06:58,085 The two males stay low. 46 00:07:15,352 --> 00:07:19,106 A few pterosaurs are almost within striking distance. 47 00:07:39,334 --> 00:07:44,173 She has one, but now the whole colony is alarmed. 48 00:08:06,278 --> 00:08:09,198 In the chaos, her victim slips from the ledge. 49 00:08:18,707 --> 00:08:22,753 The female puts the effectiveness of her feathered tail to the test. 50 00:08:27,591 --> 00:08:30,636 And, in the end, she gets her meal. 51 00:08:33,847 --> 00:08:37,726 The males are left to face the pterosaurs. 52 00:08:47,152 --> 00:08:50,948 The power of fresh water is at work all around the planet. 53 00:08:57,037 --> 00:08:58,789 Global temperatures are high. 54 00:09:00,082 --> 00:09:03,252 There are violent storms and torrential rains. 55 00:09:15,681 --> 00:09:19,977 Much of North America is covered by thick, lush forest. 56 00:09:25,065 --> 00:09:30,070 Here live some of the most gigantic plant-eaters that have ever existed. 57 00:09:33,115 --> 00:09:38,453 And they, in turn, are prey for the most ferocious of hunters. 58 00:10:09,776 --> 00:10:12,487 Tyrannosaurus rex. 59 00:10:14,823 --> 00:10:19,077 This old male has just brought down a Triceratops. 60 00:10:25,292 --> 00:10:27,920 But in doing so, he's been injured. 61 00:10:37,679 --> 00:10:41,225 T. rex are built for hunting large herbivores… 62 00:10:43,936 --> 00:10:47,314 though many of those have evolved heavy defensive weapons. 63 00:10:55,030 --> 00:10:59,034 Decades of battling armored prey has scarred his body. 64 00:11:07,668 --> 00:11:10,546 One battle even cost him the tip of his tail. 65 00:11:19,555 --> 00:11:22,724 These new injuries are more serious. 66 00:11:28,105 --> 00:11:32,818 At his great age, infection is a real risk. 67 00:11:46,999 --> 00:11:49,918 River water could help to clean his wounds. 68 00:12:02,055 --> 00:12:06,226 He stands a good chance of living to fight another day. 69 00:12:10,189 --> 00:12:12,691 But that day could come sooner than expected. 70 00:12:28,498 --> 00:12:30,167 Another T. rex. 71 00:12:38,425 --> 00:12:39,468 A stranger. 72 00:12:53,232 --> 00:12:56,777 But this newcomer has a different smell. 73 00:13:02,282 --> 00:13:03,367 It's a female. 74 00:13:04,159 --> 00:13:06,912 She's younger and smaller. 75 00:13:12,459 --> 00:13:15,629 But nonetheless, she might also be a rival. 76 00:13:25,430 --> 00:13:29,852 He, however, makes it clear that he's not interested in fighting. 77 00:13:35,315 --> 00:13:37,192 He would prefer to mate. 78 00:13:47,828 --> 00:13:49,496 She seems to approve. 79 00:14:00,048 --> 00:14:04,553 The facial area of a tyrannosaur is very sensitive to touch, 80 00:14:06,471 --> 00:14:07,598 and they nuzzle. 81 00:14:13,270 --> 00:14:18,901 His great size and his battle scars are evidence that he is a survivor. 82 00:14:21,195 --> 00:14:25,449 And that perhaps, in her eyes, makes him an attractive partner. 83 00:14:44,718 --> 00:14:46,720 So, they stay together. 84 00:14:47,221 --> 00:14:50,557 And in the coming weeks, they mate frequently. 85 00:14:52,851 --> 00:14:56,522 Eventually, she'll lay up to 15 eggs. 86 00:14:58,982 --> 00:15:02,694 And with them comes the promise of the next generation. 87 00:15:14,414 --> 00:15:20,087 Habitats that depend on fresh water can change rapidly and radically. 88 00:15:26,176 --> 00:15:27,970 In parts of central Asia, 89 00:15:28,053 --> 00:15:32,099 heavy seasonal rains fill the rivers until, eventually, 90 00:15:32,182 --> 00:15:34,017 they overflow their banks. 91 00:15:37,771 --> 00:15:40,274 The surrounding plains are flooded. 92 00:15:53,370 --> 00:15:59,334 And through the water wades one of the most bizarre of all dinosaurs. 93 00:16:19,229 --> 00:16:20,898 Deinocheirus. 94 00:16:23,942 --> 00:16:26,486 It's even taller than T. rex. 95 00:16:28,572 --> 00:16:32,034 And its massive duck-bill snout is very effective 96 00:16:32,117 --> 00:16:33,869 in gathering water plants. 97 00:16:35,829 --> 00:16:38,582 This male feeds voraciously, 98 00:16:38,665 --> 00:16:41,960 having eaten very little during the long dry season. 99 00:16:46,131 --> 00:16:48,926 Water plants are rich in nutrients. 100 00:16:50,135 --> 00:16:53,514 And his huge, curved claws, eight inches long, 101 00:16:53,597 --> 00:16:57,351 enable him to dredge them up from deep beneath the surface. 102 00:17:08,904 --> 00:17:12,741 He himself is a source of food for smaller creatures. 103 00:17:17,496 --> 00:17:21,916 Bloodsucking flies, which infest his coat. 104 00:17:29,216 --> 00:17:31,969 They're irritating and even painful. 105 00:17:32,928 --> 00:17:36,682 And while his huge claws enable him to have a good scratch… 106 00:17:39,643 --> 00:17:43,564 there are always some spots that are just out of reach. 107 00:17:51,029 --> 00:17:54,074 To get to them, he needs assistance. 108 00:17:58,078 --> 00:18:01,999 A dead tree. That could be the answer. 109 00:18:23,520 --> 00:18:25,105 That's much better. 110 00:18:40,037 --> 00:18:42,497 And now he can get back to feeding. 111 00:18:48,086 --> 00:18:52,299 But a diet that consists almost entirely of wet vegetation 112 00:18:52,382 --> 00:18:56,303 does have one inevitable consequence. 113 00:19:09,691 --> 00:19:15,739 What was food for one becomes fertilizer for many others. 114 00:19:21,286 --> 00:19:24,873 And a giant as big as Deinocheirus can produce 115 00:19:24,957 --> 00:19:28,126 over 20 tons of dung every year. 116 00:19:39,805 --> 00:19:41,265 Southern Africa. 117 00:19:43,976 --> 00:19:47,187 Here, too, the annual rains create floods. 118 00:19:50,065 --> 00:19:53,819 And the land turns into a maze of narrow channels 119 00:19:53,902 --> 00:19:56,738 running between countless small islands. 120 00:20:03,370 --> 00:20:06,373 This is now a swamp forest. 121 00:20:13,672 --> 00:20:18,760 And it attracts one of the largest flying animals that has ever lived 122 00:20:18,844 --> 00:20:20,179 on planet Earth. 123 00:20:31,690 --> 00:20:36,069 A giant pterosaur. Quetzalcoatlus. 124 00:20:49,416 --> 00:20:50,751 This is a female. 125 00:20:51,418 --> 00:20:54,254 Her wings are over 30 feet across. 126 00:20:57,090 --> 00:21:00,260 And she's come here for one particular reason. 127 00:21:28,914 --> 00:21:31,792 The small islands created by the rising waters 128 00:21:32,793 --> 00:21:35,504 are just the place for her to lay her eggs. 129 00:21:50,561 --> 00:21:53,814 Quetzalcoatlus are certainly masters of flight. 130 00:21:53,897 --> 00:21:58,235 But they're also, perhaps surprisingly, very competent on the ground. 131 00:22:00,779 --> 00:22:05,659 Each wing is supported by the single greatly elongated bone 132 00:22:05,742 --> 00:22:07,286 of her fourth finger. 133 00:22:08,245 --> 00:22:10,247 By turning her wings upwards, 134 00:22:10,330 --> 00:22:13,667 she can walk very effectively on all fours. 135 00:22:25,387 --> 00:22:28,223 She's come here to make a nest. 136 00:22:35,689 --> 00:22:39,526 She chooses to do so on damp, swampy soil 137 00:22:39,610 --> 00:22:43,197 that will prevent her soft-shelled eggs from drying out. 138 00:23:10,849 --> 00:23:13,560 These first two are just the start. 139 00:23:25,864 --> 00:23:29,910 For the next three weeks, she will guard the open nest… 140 00:23:37,000 --> 00:23:40,796 and add two more eggs every few days. 141 00:23:50,764 --> 00:23:54,434 Producing eggs takes a lot of effort and energy. 142 00:23:55,269 --> 00:23:58,939 Each one is huge, weighing around a kilo. 143 00:24:12,578 --> 00:24:16,331 Eventually, she produces a clutch of a dozen or so. 144 00:24:19,501 --> 00:24:22,754 She covers them with vegetation to conceal them. 145 00:24:34,725 --> 00:24:37,102 Now, she needs to eat. 146 00:24:39,563 --> 00:24:44,651 There should be enough food on this island to sustain her youngsters when they hatch. 147 00:24:46,236 --> 00:24:51,366 But there's nothing substantial enough here to satisfy her own hunger. 148 00:24:56,455 --> 00:25:00,083 She must leave to hunt for prey elsewhere… 149 00:25:02,127 --> 00:25:07,674 and trust that the isolation of her nest will keep her unhatched young safe 150 00:25:07,758 --> 00:25:09,176 while she's away. 151 00:25:29,363 --> 00:25:32,741 Another, much older Quetzalcoatlus female. 152 00:25:45,963 --> 00:25:49,675 She, too, is looking for a safe place to lay her eggs. 153 00:25:52,010 --> 00:25:57,516 And there may not be enough food here for two sets of giant nestlings. 154 00:25:58,851 --> 00:26:01,228 But there is a way to solve that problem. 155 00:26:12,281 --> 00:26:15,492 And eggs, after all, are very nutritious. 156 00:26:43,145 --> 00:26:45,480 The owner of the nest is back. 157 00:27:24,728 --> 00:27:27,231 The older female is driven off. 158 00:27:35,155 --> 00:27:37,866 But the younger female's nest is wrecked. 159 00:28:01,932 --> 00:28:06,603 Out of the dozen eggs that she laid, only three have survived. 160 00:28:12,860 --> 00:28:18,615 The success of her breeding season now rests on these three fragile eggs. 161 00:28:23,579 --> 00:28:28,750 She will protect them as best she can until they hatch in a few months' time. 162 00:28:31,795 --> 00:28:35,966 But after that, her young will have to fend for themselves. 163 00:28:42,723 --> 00:28:44,975 As river water flows downstream, 164 00:28:45,058 --> 00:28:51,273 it scours out billions of tons of sand and gravel and even shifts great boulders. 165 00:28:54,443 --> 00:28:58,197 The finer sediments may be transported for hundreds of miles, 166 00:28:58,280 --> 00:29:01,283 but as the river broadens, it slows. 167 00:29:02,868 --> 00:29:07,122 And as a consequence, it begins to drop some of its load. 168 00:29:13,629 --> 00:29:18,425 And animals whose ancestors lived in the sea begin to appear. 169 00:29:24,264 --> 00:29:25,265 Crabs. 170 00:29:30,020 --> 00:29:33,273 In some places, there may be dozens per square meter. 171 00:29:48,080 --> 00:29:50,832 This is Masiakasaurus. 172 00:29:51,667 --> 00:29:53,919 A female, six feet long. 173 00:29:54,002 --> 00:29:56,839 And she has a mouthful of needle-sharp teeth. 174 00:29:59,383 --> 00:30:03,679 Just what you need to deal with awkward, multi-legged prey. 175 00:30:23,073 --> 00:30:28,370 Crabs may have hard shells, but they're full of protein. 176 00:30:31,748 --> 00:30:34,209 Too good an opportunity to miss. 177 00:30:44,845 --> 00:30:46,430 And not only for her. 178 00:30:51,852 --> 00:30:53,562 She has three young. 179 00:30:57,024 --> 00:30:59,359 Only four inches tall. 180 00:31:03,197 --> 00:31:06,533 And not quite ready to take on large crabs. 181 00:31:15,167 --> 00:31:18,003 They still rely on their mother's leftovers. 182 00:31:23,759 --> 00:31:27,346 But some youngsters develop hunting instincts early. 183 00:31:37,397 --> 00:31:38,565 Very tempting. 184 00:31:45,489 --> 00:31:48,242 The smallest crabs can be swallowed whole. 185 00:31:54,456 --> 00:32:00,087 Unfortunately, what they lack in size, they make up for in speed. 186 00:32:18,105 --> 00:32:21,775 It's best for the young not to stray too far. 187 00:32:45,299 --> 00:32:48,886 Beelzebufo, the devil toad. 188 00:32:50,721 --> 00:32:54,183 One of the largest frogs that has ever existed. 189 00:33:05,861 --> 00:33:09,323 He won't need to feed again for a month. 190 00:33:19,208 --> 00:33:22,252 These sandbars may be a rich feeding ground, 191 00:33:22,336 --> 00:33:25,923 but there can be a high price to pay for living here. 192 00:33:35,140 --> 00:33:38,477 The river water is now approaching the sea. 193 00:33:42,022 --> 00:33:45,859 A taste of salt in its waters is already detectable. 194 00:33:53,700 --> 00:33:54,868 At high tide, 195 00:33:54,952 --> 00:33:59,289 visitors come in from the open sea to explore these channels. 196 00:34:35,909 --> 00:34:37,661 Elasmosaurs. 197 00:34:39,830 --> 00:34:43,333 These are true oceangoing reptiles. 198 00:34:45,793 --> 00:34:50,215 But some come to estuaries to explore the brackish waters. 199 00:35:29,296 --> 00:35:32,007 Now, the millions of tons of sediment carried here 200 00:35:32,090 --> 00:35:35,636 by rivers is finally delivered into the sea. 201 00:35:41,391 --> 00:35:45,604 The river water takes time to mix with the ocean, and, for a while, 202 00:35:45,687 --> 00:35:48,607 the two waters flow side by side. 203 00:35:51,485 --> 00:35:52,486 Nonetheless, 204 00:35:52,569 --> 00:35:57,533 great shoals of fish find plenty on which to feed in these waters. 205 00:36:01,662 --> 00:36:06,625 The clouds of sediment conceal the fish, if they're any distance away. 206 00:36:09,670 --> 00:36:14,550 But the Elasmosaurs don't hesitate to swim into the murkiest of waters 207 00:36:14,633 --> 00:36:16,218 to pursue their prey. 208 00:36:35,779 --> 00:36:37,990 There is no escape for the fish… 209 00:36:45,706 --> 00:36:47,791 even above the water. 210 00:37:07,936 --> 00:37:12,441 These Elasmosaurs collect the last of the river's gifts 211 00:37:12,524 --> 00:37:19,198 before its traces are finally lost in the oceans of the prehistoric planet. 212 00:37:31,543 --> 00:37:33,587 Next on Prehistoric Planet, 213 00:37:33,670 --> 00:37:38,008 the bond between mother and young is tested to the limit 214 00:37:38,091 --> 00:37:40,093 as they struggle to survive. 215 00:37:40,802 --> 00:37:44,932 Ancient foes battle each other and freezing blizzards. 216 00:37:46,141 --> 00:37:49,978 And feathered dinosaurs rule the ice worlds. 217 00:37:50,646 --> 00:37:53,649 To discover the science behind the stories, 218 00:37:53,732 --> 00:37:58,070 go now to the Prehistoric Planet show page.