1 00:00:18,560 --> 00:00:21,040 Almost 200 years ago, 2 00:00:21,160 --> 00:00:24,880 whilst walking these very paths in the English countryside 3 00:00:25,000 --> 00:00:28,360 and observing the banks and meadows near his home, 4 00:00:28,480 --> 00:00:31,120 Charles Darwin developed his ground-breaking ideas 5 00:00:31,240 --> 00:00:32,440 about evolution, 6 00:00:32,560 --> 00:00:35,360 casting a new light on the natural world 7 00:00:35,480 --> 00:00:38,680 and opening our eyes to its true wonder. 8 00:00:38,800 --> 00:00:43,680 Since then, we've explored almost every part of the planet 9 00:00:43,800 --> 00:00:47,440 and seen nature in its astounding variety. 10 00:00:47,560 --> 00:00:50,400 But there's still much to discover. 11 00:00:53,240 --> 00:00:57,080 In this new series of Planet Earth, 12 00:00:57,200 --> 00:01:00,920 we travel to the most astonishing wild places... 13 00:01:03,560 --> 00:01:05,360 ...see mysterious creatures... 14 00:01:11,080 --> 00:01:14,040 ...witness spectacular wonders... 15 00:01:15,800 --> 00:01:18,960 ...and reveal breathtaking animal dramas. 16 00:01:24,240 --> 00:01:26,120 (SNARLS) 17 00:01:34,440 --> 00:01:38,280 The natural world continues to surprise us. 18 00:01:42,200 --> 00:01:47,440 But since Darwin's time, it has changed beyond recognition... 19 00:01:48,800 --> 00:01:53,520 ...transformed by a powerful force - us. 20 00:01:56,080 --> 00:02:00,800 We will see how animals are adapting in extraordinary ways 21 00:02:00,920 --> 00:02:03,880 to survive the new challenges they face. 22 00:02:06,920 --> 00:02:09,120 At this crucial time in our history, 23 00:02:09,240 --> 00:02:11,280 we must now look at the world 24 00:02:11,400 --> 00:02:13,800 through a new lens. 25 00:02:13,920 --> 00:02:17,040 This is Planet Earth III. 26 00:02:59,360 --> 00:03:01,240 Tasmania, 27 00:03:01,360 --> 00:03:03,440 Shipstern's Bluff, 28 00:03:03,560 --> 00:03:07,120 where two worlds collide. 29 00:03:29,800 --> 00:03:31,320 These waves have crossed 30 00:03:31,440 --> 00:03:34,240 more than a thousand miles of open ocean... 31 00:03:37,160 --> 00:03:39,640 ...building in strength. 32 00:03:53,480 --> 00:03:57,120 It's here that they meet their explosive end. 33 00:04:23,720 --> 00:04:28,680 Coasts are dangerous and dynamic frontiers. 34 00:04:28,800 --> 00:04:33,360 To succeed here, life must adapt to constant change. 35 00:04:40,040 --> 00:04:42,560 South Africa's Robberg Peninsula. 36 00:04:46,640 --> 00:04:50,320 Thousands of Cape fur seals gather here to breed. 37 00:04:52,720 --> 00:04:55,880 (SEALS BARKING) 38 00:05:03,400 --> 00:05:07,560 This pup was born into a crowded world. 39 00:05:11,400 --> 00:05:13,960 But now, at nearly a year old, 40 00:05:14,080 --> 00:05:16,920 he can escape to the water. 41 00:05:24,320 --> 00:05:26,080 He just has to get there. 42 00:05:32,560 --> 00:05:33,560 (SNARLS) 43 00:05:33,680 --> 00:05:35,320 (GRUNTS) 44 00:05:57,120 --> 00:06:02,560 There is no question as to where this pup belongs. 45 00:06:10,480 --> 00:06:15,200 In the water, he's fast and agile... 46 00:06:27,320 --> 00:06:29,720 ...and he needs to be. 47 00:06:33,160 --> 00:06:37,960 The rolling surf conceals life-threatening dangers. 48 00:07:04,320 --> 00:07:06,520 (SEAL YELPS) 49 00:07:09,920 --> 00:07:12,520 A great white shark. 50 00:07:29,920 --> 00:07:34,400 This young pup has had a very lucky escape. 51 00:07:50,600 --> 00:07:52,400 (SEALS BARKING) 52 00:07:52,520 --> 00:07:54,760 Here on Africa's southern coast, 53 00:07:54,880 --> 00:07:57,640 seals risk their lives every time 54 00:07:57,760 --> 00:08:00,280 they set out to eat. 55 00:08:05,000 --> 00:08:10,200 Powerful ocean currents attract huge shoals of fish. 56 00:08:18,880 --> 00:08:21,200 But in recent years, 57 00:08:21,320 --> 00:08:24,040 this stretch has attracted increased numbers 58 00:08:24,160 --> 00:08:26,320 of great whites, too. 59 00:08:29,280 --> 00:08:31,840 The great whites are shrewd hunters 60 00:08:31,960 --> 00:08:34,600 and use whatever cover is available. 61 00:08:53,760 --> 00:08:56,840 (SEALS BARKING) 62 00:09:03,920 --> 00:09:08,000 This shark won't need to eat for another few days. 63 00:09:11,920 --> 00:09:13,880 But he's not alone. 64 00:09:17,600 --> 00:09:20,400 These usually solitary hunters 65 00:09:20,520 --> 00:09:23,280 are gathering in unprecedented numbers... 66 00:09:26,080 --> 00:09:27,880 ...a dozen at a time. 67 00:09:40,560 --> 00:09:42,360 The seals are nimble... 68 00:09:48,240 --> 00:09:50,320 ...but great whites are patient... 69 00:09:56,960 --> 00:09:59,240 ...and have explosive acceleration... 70 00:10:02,440 --> 00:10:06,480 ...hitting top speed with just five swipes of their tails. 71 00:10:18,080 --> 00:10:22,960 Cornered, the seals keep close to the jagged cliffs. 72 00:10:29,400 --> 00:10:31,480 They're trapped. 73 00:11:15,640 --> 00:11:18,840 But as the great whites move in for the kill... 74 00:11:20,640 --> 00:11:23,120 ...the seals do something astonishing. 75 00:11:27,840 --> 00:11:31,960 Together, they turn on their enemy. 76 00:11:44,800 --> 00:11:48,160 As more join, the mob grows... 77 00:11:49,840 --> 00:11:52,840 ...in both number and confidence. 78 00:12:05,720 --> 00:12:08,200 The tables are turning. 79 00:12:34,120 --> 00:12:36,440 By sheer force of numbers, 80 00:12:36,560 --> 00:12:38,600 these fur seals drive 81 00:12:38,720 --> 00:12:41,000 the world's most notorious predator... 82 00:12:43,240 --> 00:12:45,520 ...back out to sea. 83 00:12:52,800 --> 00:12:57,080 Here, animals are adapting to new challenges 84 00:12:57,200 --> 00:12:59,640 in a rapidly changing world. 85 00:13:08,120 --> 00:13:10,280 In the Arctic, 86 00:13:10,400 --> 00:13:14,320 monumental change is a regular event. 87 00:13:19,760 --> 00:13:21,920 (BLOWS) 88 00:13:22,040 --> 00:13:26,120 Summer. Visitors are arriving en masse... 89 00:13:27,400 --> 00:13:31,240 ...attracted by the biggest seasonal transformation 90 00:13:31,360 --> 00:13:33,040 on any coast on Earth. 91 00:13:44,080 --> 00:13:48,920 Over 300 billion tons of ice are melting... 92 00:13:53,520 --> 00:13:56,640 ...releasing nutrient-rich water. 93 00:14:00,920 --> 00:14:04,120 Extraordinary newcomers appear from the depths. 94 00:14:15,640 --> 00:14:17,160 A sea angel... 95 00:14:19,960 --> 00:14:22,640 ...no bigger than your little finger. 96 00:14:31,960 --> 00:14:34,480 It's eaten little for months. 97 00:14:34,600 --> 00:14:37,840 Its empty stomach glows orange. 98 00:14:48,320 --> 00:14:51,120 And there are other hungry arrivals. 99 00:14:56,160 --> 00:14:57,840 A sea butterfly... 100 00:14:59,840 --> 00:15:02,000 ...a snail with wings. 101 00:15:10,880 --> 00:15:14,800 Both angel and butterfly are blind... 102 00:15:16,520 --> 00:15:19,960 ...but each monitors minute changes in the water 103 00:15:20,080 --> 00:15:22,160 as they search for a meal. 104 00:15:37,320 --> 00:15:40,360 This angel has a devilish side. 105 00:15:43,280 --> 00:15:46,640 Its mouthparts invert... 106 00:15:46,760 --> 00:15:49,640 ...to form a deadly trap of tentacles... 107 00:16:00,520 --> 00:16:03,760 ...from which there is little chance of escape. 108 00:16:42,120 --> 00:16:44,280 With a stomach full of prey, 109 00:16:44,400 --> 00:16:47,000 this angel has lost its glow... 110 00:16:49,000 --> 00:16:50,920 ...but not its appetite. 111 00:16:56,000 --> 00:16:58,760 It feasts while it can. 112 00:17:05,160 --> 00:17:07,040 Both predator and prey 113 00:17:07,160 --> 00:17:09,520 will soon return to the depths... 114 00:17:10,760 --> 00:17:14,720 ...before the ice transforms this coast once again. 115 00:17:18,640 --> 00:17:20,560 (WIND GUSTS) 116 00:17:32,880 --> 00:17:35,080 Namibia, 117 00:17:35,200 --> 00:17:39,520 where desert lions roam across vast territories. 118 00:17:39,640 --> 00:17:42,080 (LION GROWLS) 119 00:17:48,400 --> 00:17:53,200 These desert cats are on a never-ending search for food. 120 00:17:59,600 --> 00:18:02,280 And that has brought these young sisters... 121 00:18:03,680 --> 00:18:05,120 ...here... 122 00:18:14,960 --> 00:18:18,680 ...Africa's infamous Skeleton Coast. 123 00:18:24,400 --> 00:18:26,440 Following years of persecution, 124 00:18:26,560 --> 00:18:29,600 Namibia's lions are now protected, 125 00:18:29,720 --> 00:18:31,160 and their range 126 00:18:31,280 --> 00:18:32,960 is expanding again. 127 00:18:35,000 --> 00:18:36,960 These are the first to be seen 128 00:18:37,080 --> 00:18:39,440 on these shores for 40 years. 129 00:18:44,160 --> 00:18:47,840 By day, there is little for them here. 130 00:18:47,960 --> 00:18:50,680 (GROWLS SOFTLY) 131 00:18:50,800 --> 00:18:53,800 But at night, it's a different story. 132 00:18:58,080 --> 00:19:01,000 (BIRDS CALL) 133 00:19:03,920 --> 00:19:08,440 Sea birds come here to roost in their thousands. 134 00:19:19,240 --> 00:19:23,680 These hungry sisters have never seen an opportunity like this. 135 00:19:28,040 --> 00:19:31,520 But no cats, certainly no desert cats, 136 00:19:31,640 --> 00:19:34,520 enjoy getting their paws wet. 137 00:19:47,080 --> 00:19:52,240 These roosting cormorants are sitting ducks 138 00:19:52,360 --> 00:19:54,960 for hunters with good night vision... 139 00:19:58,920 --> 00:20:02,120 (BIRDS SQUAWK) 140 00:20:05,400 --> 00:20:06,720 ...in theory. 141 00:20:16,760 --> 00:20:19,640 Birds are not a big cat's usual prey, 142 00:20:19,760 --> 00:20:21,800 let alone sea birds... 143 00:20:23,680 --> 00:20:26,880 ...and these sisters need to get their eye in. 144 00:20:56,280 --> 00:20:58,000 (CHICK CHIRPS) 145 00:20:59,760 --> 00:21:03,600 Catching flying prey in the dark is not easy... 146 00:21:04,680 --> 00:21:07,840 ...but these lions have acquired the knack. 147 00:21:12,160 --> 00:21:14,840 Coasts can not only provide food... 148 00:21:27,680 --> 00:21:30,680 ...they can also be a sanctuary. 149 00:21:34,320 --> 00:21:36,960 (WHALE GRUNTS) 150 00:21:41,440 --> 00:21:43,320 (CLICKING) 151 00:21:43,440 --> 00:21:47,120 This female southern right whale is nearing the end 152 00:21:47,240 --> 00:21:51,520 of a 5,000-mile journey across open ocean. 153 00:22:04,440 --> 00:22:06,760 She's kept a steady course... 154 00:22:08,680 --> 00:22:12,200 ...to a special place she has known all her life... 155 00:22:17,120 --> 00:22:20,560 ...Península Valdés, Argentina. 156 00:22:43,080 --> 00:22:46,360 In these calm, shallow waters, 157 00:22:46,480 --> 00:22:49,480 her behaviour starts to change. 158 00:22:51,760 --> 00:22:55,200 She rolls and shifts her great body. 159 00:23:00,120 --> 00:23:02,760 Perhaps she's trying to get comfortable. 160 00:23:02,880 --> 00:23:04,880 (GRUNTS) 161 00:23:11,080 --> 00:23:13,400 (GRUNTS) 162 00:23:25,760 --> 00:23:27,920 (GRUNTS) 163 00:23:31,240 --> 00:23:33,360 Other females are close by. 164 00:23:37,040 --> 00:23:40,280 Some have been coming here for five decades... 165 00:23:41,600 --> 00:23:43,800 ...seeking the shelter of this bay 166 00:23:43,920 --> 00:23:46,080 at a key time in their lives. 167 00:23:48,800 --> 00:23:51,280 (GRUNTING) 168 00:24:03,000 --> 00:24:06,360 This whale is here 169 00:24:06,480 --> 00:24:08,720 to give birth. 170 00:24:35,440 --> 00:24:37,160 (BLOWS) 171 00:24:38,640 --> 00:24:41,520 A new life begins. 172 00:24:53,400 --> 00:24:56,720 The calf is totally dependent on its mother. 173 00:24:59,440 --> 00:25:04,160 She's producing as much as 200 litres of milk a day. 174 00:25:06,520 --> 00:25:08,400 The strength she loses, 175 00:25:08,520 --> 00:25:10,920 the calf gains... 176 00:25:16,880 --> 00:25:22,160 ...and it becomes more and more independent and playful. 177 00:25:31,960 --> 00:25:33,640 In this nursery bay, 178 00:25:33,760 --> 00:25:36,480 there are plenty of playmates. 179 00:25:46,600 --> 00:25:50,360 But a mother never lets her calf stray too far... 180 00:25:57,840 --> 00:26:02,080 ...and will always offer a welcome embrace. 181 00:26:10,800 --> 00:26:14,920 (CALLS GENTLY) 182 00:26:15,040 --> 00:26:20,400 The family keeps in constant contact with whispered calls. 183 00:26:21,840 --> 00:26:25,680 New research has revealed that in shallow coastal waters 184 00:26:25,800 --> 00:26:29,400 their calls not only fade quickly, 185 00:26:29,520 --> 00:26:31,080 but are also concealed 186 00:26:31,200 --> 00:26:34,360 by the sound of waves breaking on the shore... 187 00:26:34,480 --> 00:26:36,160 (WAVES LAP) 188 00:26:36,280 --> 00:26:38,120 (WHALE CALLS GENTLY) 189 00:26:40,320 --> 00:26:44,240 ...so they won't attract the attention of predators. 190 00:26:49,200 --> 00:26:53,480 Not so long ago, these whales faced a graver threat. 191 00:26:56,600 --> 00:26:59,400 They were hunted to near extinction. 192 00:27:02,440 --> 00:27:04,000 But 40 years ago, 193 00:27:04,120 --> 00:27:07,120 commercial whaling was banned. 194 00:27:10,360 --> 00:27:15,360 Today, their population is 12,000 strong, 195 00:27:15,480 --> 00:27:19,000 and this bay now attracts one of the largest gatherings 196 00:27:19,120 --> 00:27:22,320 of these whales anywhere on Earth. 197 00:27:43,760 --> 00:27:48,280 There are over a million miles of coastline around the world. 198 00:27:49,840 --> 00:27:51,640 Together, they constitute 199 00:27:51,760 --> 00:27:54,880 the most varied habitat on the planet. 200 00:27:58,560 --> 00:28:01,200 Here, on Canada's west coast, 201 00:28:01,320 --> 00:28:04,720 some of the most powerful of all ocean currents 202 00:28:04,840 --> 00:28:07,720 deliver a constant supply of nutrients 203 00:28:07,840 --> 00:28:10,520 to the shores of countless islands. 204 00:28:13,480 --> 00:28:15,280 (BIRDSONG) 205 00:28:24,560 --> 00:28:26,480 And those that live here 206 00:28:26,600 --> 00:28:28,840 take full advantage. 207 00:28:35,120 --> 00:28:40,400 This is the aptly named wandering garter snake. 208 00:28:45,240 --> 00:28:48,000 (HISSES) 209 00:28:50,280 --> 00:28:51,560 (HISSES) 210 00:28:58,360 --> 00:29:00,200 He may seem out of place, 211 00:29:00,320 --> 00:29:03,000 but he's here to eat. 212 00:29:14,920 --> 00:29:18,440 The water here is more than ten degrees colder 213 00:29:18,560 --> 00:29:19,920 than the air. 214 00:29:25,960 --> 00:29:29,920 But that doesn't deter this intrepid hunter 215 00:29:30,040 --> 00:29:31,880 from taking the plunge. 216 00:29:37,400 --> 00:29:41,120 Under the water, there is an abundance of food... 217 00:29:43,160 --> 00:29:44,760 ...if you can catch it. 218 00:30:12,200 --> 00:30:13,920 Snakes are cold-blooded, 219 00:30:14,040 --> 00:30:17,560 so he can't stay in these chilly waters for long. 220 00:30:24,920 --> 00:30:28,080 Back in the sunshine, he warms his head, 221 00:30:28,200 --> 00:30:31,120 perhaps sharpening his senses. 222 00:30:34,080 --> 00:30:36,240 And then, with a gulp of air... 223 00:30:38,000 --> 00:30:39,800 ...he continues his hunt. 224 00:30:47,200 --> 00:30:48,960 It's thought that garter snakes 225 00:30:49,080 --> 00:30:51,760 can use their forked tongue underwater, 226 00:30:51,880 --> 00:30:56,800 as they do in air, smelling in stereo, 227 00:30:56,920 --> 00:30:59,960 detecting prey wherever it hides. 228 00:31:15,880 --> 00:31:17,280 He's got something. 229 00:31:18,640 --> 00:31:20,080 A small fish. 230 00:31:25,520 --> 00:31:27,920 Now he has to land it. 231 00:31:31,880 --> 00:31:33,320 Success. 232 00:31:38,240 --> 00:31:40,960 For those animals able to cross the divide 233 00:31:41,080 --> 00:31:45,440 between land and sea, there are surprising rewards. 234 00:31:51,960 --> 00:31:54,920 Raja Ampat in Indonesia. 235 00:31:58,640 --> 00:32:01,840 Here, there's a greater variety of animals 236 00:32:01,960 --> 00:32:04,400 than on any other coast on Earth. 237 00:32:10,520 --> 00:32:13,600 The corals are protected by mangroves, 238 00:32:13,720 --> 00:32:16,320 salt-tolerant trees 239 00:32:16,440 --> 00:32:20,240 that prop themselves on curving aerial roots. 240 00:32:33,200 --> 00:32:36,080 These fish have learned how to catch prey 241 00:32:36,200 --> 00:32:38,520 from high in the trees. 242 00:32:44,560 --> 00:32:48,480 Archerfish use jets of water like arrows. 243 00:32:53,280 --> 00:32:55,840 This pinpoint accuracy 244 00:32:55,960 --> 00:32:58,800 requires some complex calculations. 245 00:33:00,760 --> 00:33:04,400 The hunter first estimates the range of its target... 246 00:33:07,480 --> 00:33:11,120 ...then loads with a precise amount of water. 247 00:33:11,240 --> 00:33:12,320 (GULPS) 248 00:33:13,400 --> 00:33:17,640 Aiming, they allow for the refraction and distortion 249 00:33:17,760 --> 00:33:20,520 created by the water's moving surface. 250 00:33:24,360 --> 00:33:26,360 And then... 251 00:33:26,480 --> 00:33:28,400 ...release... 252 00:33:30,920 --> 00:33:32,680 ...an arrow of water. 253 00:33:35,080 --> 00:33:37,480 They can hit prey 254 00:33:37,600 --> 00:33:40,440 up to two metres above them. 255 00:33:49,320 --> 00:33:52,560 But they're not born with this skill. 256 00:33:54,480 --> 00:33:56,000 They have to learn it. 257 00:33:58,120 --> 00:34:01,360 And they do that by studying others. 258 00:34:06,320 --> 00:34:11,400 This youngster is watching a master at work. 259 00:34:27,320 --> 00:34:30,320 It's time for the apprentice to have a go. 260 00:34:33,040 --> 00:34:36,000 First, he must select a target. 261 00:34:39,320 --> 00:34:41,360 This seems rather ambitious. 262 00:34:50,280 --> 00:34:51,760 Missed. 263 00:34:53,040 --> 00:34:55,960 Others watch to learn from his mistakes... 264 00:35:06,040 --> 00:35:07,400 ...or... 265 00:35:09,680 --> 00:35:11,520 ...to steal his prize. 266 00:35:48,600 --> 00:35:50,880 Enough is enough. 267 00:35:52,960 --> 00:35:55,360 There is one way to beat the thieves. 268 00:36:00,440 --> 00:36:03,160 The archer himself 269 00:36:03,280 --> 00:36:05,320 becomes the arrow. 270 00:36:26,920 --> 00:36:30,920 Mangroves are unusually stable coastal environments, 271 00:36:31,040 --> 00:36:35,360 where an archerfish can focus on beating the competition. 272 00:36:54,920 --> 00:36:59,000 But on the exposed coast of Mexico's Yucatán, 273 00:36:59,120 --> 00:37:01,080 life is precarious. 274 00:37:03,560 --> 00:37:06,600 Concentrated by the tropical sunshine, 275 00:37:06,720 --> 00:37:09,280 the brine in these shallow lagoons 276 00:37:09,400 --> 00:37:12,360 cannot be tolerated by most animals. 277 00:37:16,520 --> 00:37:20,040 And yet these Caribbean flamingos 278 00:37:20,160 --> 00:37:23,400 have flown hundreds of miles to gather here. 279 00:37:47,000 --> 00:37:49,760 (FLAMINGOS SQUAWK) 280 00:37:59,760 --> 00:38:04,280 These hypersaline waters keep many predators at bay... 281 00:38:07,240 --> 00:38:10,000 ...so it's here they choose to nest. 282 00:38:12,960 --> 00:38:15,800 There are more than 10,000 pairs here. 283 00:38:15,920 --> 00:38:19,400 It's the largest breeding colony in North America. 284 00:38:19,520 --> 00:38:21,240 (FLAMINGOS SQUAWKING) 285 00:38:33,440 --> 00:38:36,760 Nest mounds keep chicks clear of the brine 286 00:38:36,880 --> 00:38:39,640 while they're still at their most vulnerable. 287 00:38:41,920 --> 00:38:43,200 (CHIRPS) 288 00:38:49,720 --> 00:38:51,120 (CHIRPS) 289 00:39:00,520 --> 00:39:02,160 (CHIRPS) 290 00:39:02,280 --> 00:39:03,800 (CHIRPING) 291 00:39:15,960 --> 00:39:19,000 But this generation faces a problem. 292 00:39:19,120 --> 00:39:20,280 (CHIRPS) 293 00:39:20,400 --> 00:39:23,480 (THUNDER RUMBLES) 294 00:39:27,160 --> 00:39:29,240 The storms that come each season 295 00:39:29,360 --> 00:39:32,200 are arriving earlier every year... 296 00:39:35,880 --> 00:39:39,800 ...and the colony lies directly in their path. 297 00:39:40,840 --> 00:39:43,440 (WIND GUSTS) 298 00:39:49,960 --> 00:39:53,800 Rising winds create a storm surge 299 00:39:53,920 --> 00:39:57,320 that overwhelms the most exposed nests. 300 00:39:58,720 --> 00:40:00,840 (SQUAWKING) 301 00:40:11,920 --> 00:40:14,640 (THUNDER RUMBLES) 302 00:40:20,680 --> 00:40:24,120 And then... it rains. 303 00:40:32,720 --> 00:40:36,800 The adults do what they can, bailing out their nests. 304 00:40:43,760 --> 00:40:46,400 But they can only do so much. 305 00:41:02,960 --> 00:41:08,200 The storm passes... but leaves devastation in its wake. 306 00:41:12,760 --> 00:41:15,040 Most nests are submerged. 307 00:41:26,160 --> 00:41:28,400 (CHIRPS) 308 00:41:31,640 --> 00:41:34,280 The chicks are soaked and cold... 309 00:41:36,000 --> 00:41:38,800 ...and will soon perish 310 00:41:38,920 --> 00:41:41,560 unless they can get out of the water. 311 00:41:47,920 --> 00:41:49,920 (CHIRPING) 312 00:41:55,320 --> 00:41:58,120 The adults are unable to help. 313 00:42:02,600 --> 00:42:05,240 A chick must save itself. 314 00:42:13,840 --> 00:42:15,920 (WATER SPLASHES) 315 00:42:16,040 --> 00:42:17,720 (CHIRPING) 316 00:42:31,720 --> 00:42:33,040 Some years, 317 00:42:33,160 --> 00:42:36,280 no chicks survive in this colony. 318 00:42:40,120 --> 00:42:44,280 Our coasts are vulnerable places, 319 00:42:44,400 --> 00:42:47,960 increasingly so as rising global temperatures 320 00:42:48,080 --> 00:42:50,120 create bigger storms. 321 00:42:52,680 --> 00:42:54,280 (RUMBLING) 322 00:42:54,400 --> 00:42:57,680 The biggest are hurricanes. 323 00:43:01,040 --> 00:43:04,080 They form over warm tropical water, 324 00:43:04,200 --> 00:43:06,600 building in strength at sea. 325 00:43:09,880 --> 00:43:13,760 But their full force is unleashed on our coasts... 326 00:43:16,680 --> 00:43:20,360 ...where 40% of the world's human population 327 00:43:20,480 --> 00:43:22,040 have made their homes. 328 00:43:35,280 --> 00:43:37,240 In this changing world... 329 00:43:39,000 --> 00:43:41,480 ...coasts are on the front line. 330 00:43:57,960 --> 00:44:00,480 Raine Island, 331 00:44:00,600 --> 00:44:03,640 one of the planet's most important breeding sites 332 00:44:03,760 --> 00:44:06,920 for one particularly precious species. 333 00:44:20,960 --> 00:44:22,880 The green turtle. 334 00:44:27,040 --> 00:44:29,800 On a few special nights each year, 335 00:44:29,920 --> 00:44:33,760 as many as 20,000 females come ashore here. 336 00:44:36,520 --> 00:44:38,880 Their instinct to nest is strong... 337 00:44:41,280 --> 00:44:45,280 ...and many haul themselves far inland 338 00:44:45,400 --> 00:44:46,960 in search of nesting space. 339 00:44:49,720 --> 00:44:51,440 In a single night, 340 00:44:51,560 --> 00:44:54,920 they may lay as many as two million eggs. 341 00:44:56,520 --> 00:44:58,440 (HUFFS) 342 00:45:03,920 --> 00:45:07,240 (BIRDS SQUAWK) 343 00:45:08,360 --> 00:45:09,600 Dawn. 344 00:45:12,480 --> 00:45:15,720 This exhausted female has nested, 345 00:45:15,840 --> 00:45:18,840 but now she faces a long return journey 346 00:45:18,960 --> 00:45:21,360 through the dunes to the sea. 347 00:45:21,480 --> 00:45:23,080 (HUFFS) 348 00:45:29,480 --> 00:45:31,440 (HUFFS) 349 00:45:34,520 --> 00:45:36,160 As the sun rises... 350 00:45:38,440 --> 00:45:41,760 ...she is at risk of being baked alive. 351 00:45:49,840 --> 00:45:53,720 Every inch she travels is gruelling. 352 00:46:02,000 --> 00:46:05,960 And the ebbing tide has exposed a rocky reef. 353 00:46:11,520 --> 00:46:14,320 It has already claimed many lives... 354 00:46:18,840 --> 00:46:23,160 ...other females overcome by heat and exhaustion. 355 00:46:33,400 --> 00:46:35,520 Her temperature is rising. 356 00:46:35,640 --> 00:46:37,840 She has to keep going. 357 00:46:54,960 --> 00:46:56,720 (GRUNTS) 358 00:47:03,000 --> 00:47:06,600 As many as 2,000 female turtles 359 00:47:06,720 --> 00:47:09,240 may die here each year. 360 00:47:11,000 --> 00:47:13,640 (GRUNTING) 361 00:47:30,680 --> 00:47:33,720 But the coast is always changing. 362 00:47:43,000 --> 00:47:47,480 And the turning tide may yet save her. 363 00:48:16,440 --> 00:48:19,560 Half of all the green turtles in the Pacific 364 00:48:19,680 --> 00:48:21,440 come here to nest, 365 00:48:21,560 --> 00:48:25,200 as they have done for at least 1,000 years. 366 00:48:33,920 --> 00:48:36,280 But for how much longer? 367 00:48:42,120 --> 00:48:44,680 If sea levels rise as predicted, 368 00:48:44,800 --> 00:48:47,200 within the next 30 years 369 00:48:47,320 --> 00:48:51,960 Raine Island will disappear beneath the waves. 370 00:48:59,600 --> 00:49:03,080 Coasts are dynamic, dangerous frontiers. 371 00:49:05,400 --> 00:49:08,200 And they are changing faster than ever before 372 00:49:08,320 --> 00:49:09,680 in human history. 373 00:49:13,480 --> 00:49:17,280 Life is remarkably resilient 374 00:49:17,400 --> 00:49:20,000 and adapts to new challenges. 375 00:49:22,640 --> 00:49:25,040 But there is a limit 376 00:49:25,160 --> 00:49:27,880 on how fast it can do so. 377 00:49:48,760 --> 00:49:52,240 As far as I know, I was one of the first people to film 378 00:49:52,360 --> 00:49:55,360 on Raine Island, back in 1957. 379 00:49:57,920 --> 00:50:00,000 YOUNG DAVID: After a fortnight of travelling north, 380 00:50:00,120 --> 00:50:03,600 we at last sighted Raine Island. 381 00:50:03,720 --> 00:50:06,080 From the sea, it looked no more 382 00:50:06,200 --> 00:50:08,640 than a low sandbank covered in scrub, 383 00:50:08,760 --> 00:50:11,360 but as we rowed ashore, 384 00:50:11,480 --> 00:50:15,960 we were deafened by the cries of thousands of sea birds 385 00:50:16,080 --> 00:50:18,480 which hung above the island like a black cloud. 386 00:50:21,760 --> 00:50:23,200 DAVID: I was 31, 387 00:50:23,320 --> 00:50:26,840 and it was here that I first met a green turtle. 388 00:50:28,200 --> 00:50:30,920 YOUNG DAVID: The turtles come up to lay at night, 389 00:50:31,040 --> 00:50:34,800 and after a night spent laying maybe over 100 eggs, 390 00:50:34,920 --> 00:50:36,640 she's very weary 391 00:50:36,760 --> 00:50:39,080 and very anxious to get back to the sea. 392 00:50:42,600 --> 00:50:45,720 DAVID: Nearly 70 years later, the Planet Earth III team 393 00:50:45,840 --> 00:50:47,800 are welcomed by people 394 00:50:47,920 --> 00:50:49,360 whose connection to the island 395 00:50:49,480 --> 00:50:51,480 goes back very much further than mine. 396 00:50:51,600 --> 00:50:53,520 Welcome to Raine! 397 00:50:53,640 --> 00:50:57,120 The Wuthathi and Meriam people have been coming here 398 00:50:57,240 --> 00:50:59,120 for several thousand years. 399 00:51:00,360 --> 00:51:02,760 Raine Island is a beautiful and special place. 400 00:51:02,880 --> 00:51:05,200 Like, there's nowhere else in the planet 401 00:51:05,320 --> 00:51:07,400 where you come and see this much turtles. 402 00:51:07,520 --> 00:51:09,520 It's a wonder to see. 403 00:51:13,320 --> 00:51:15,000 Since I was there, 404 00:51:15,120 --> 00:51:17,120 it's been discovered that Raine Island attracts 405 00:51:17,240 --> 00:51:20,800 more nesting green turtles than anywhere else on the planet. 406 00:51:26,960 --> 00:51:30,120 So many! As soon as you're up, you're, "Oh, there are a lot." 407 00:51:31,120 --> 00:51:34,680 And the crew soon meet some other residents, too. 408 00:51:34,800 --> 00:51:38,080 This is behind the behind-the-scenes! 409 00:51:41,120 --> 00:51:42,320 Yeah! 410 00:51:42,440 --> 00:51:44,240 Aww. See you, mate. 411 00:51:47,720 --> 00:51:49,520 The team are here to record 412 00:51:49,640 --> 00:51:52,920 the mother turtles' perilous journeys back to the sea. 413 00:51:54,880 --> 00:51:56,400 CREW MEMBER: Oh, God. 414 00:51:58,640 --> 00:52:00,920 Trapped turtles can often free themselves 415 00:52:01,040 --> 00:52:03,360 with the help of the rising tide. 416 00:52:03,480 --> 00:52:06,560 Yeah, nearly. Just a bit more to the right. There... 417 00:52:06,680 --> 00:52:07,720 Yeah, there. 418 00:52:07,840 --> 00:52:12,160 But in this case, Keron makes the decision to intervene. 419 00:52:13,160 --> 00:52:15,360 Ready? One. two, three. 420 00:52:15,480 --> 00:52:17,480 KERON: Yeah, any time we're here, 421 00:52:17,600 --> 00:52:18,840 we'll walk the beach. 422 00:52:18,960 --> 00:52:22,240 Any turtles that have no chance of making it back to the ocean, 423 00:52:22,360 --> 00:52:24,800 if we can save 'em, we save 'em, 424 00:52:24,920 --> 00:52:27,560 because every turtle is precious. 425 00:52:27,680 --> 00:52:30,400 At the time of my first visit, little was known 426 00:52:30,520 --> 00:52:32,720 to outsiders about Raine Island. 427 00:52:32,840 --> 00:52:36,120 But for the last few decades, scientists have been working 428 00:52:36,240 --> 00:52:40,040 with the Wuthathi and Meriam people to understand 429 00:52:40,160 --> 00:52:42,560 more about this special place. 430 00:52:42,680 --> 00:52:44,880 WOMAN: Scientists have been coming to Raine Island 431 00:52:45,000 --> 00:52:46,000 since about the mid-'70s, 432 00:52:46,120 --> 00:52:48,920 and over that time they've been monitoring 433 00:52:49,040 --> 00:52:50,480 the nesting population here. 434 00:52:52,400 --> 00:52:54,760 This work involves long hours... 435 00:52:56,880 --> 00:52:58,520 98.7, yeah. 436 00:52:58,640 --> 00:53:00,720 ...and a certain degree of patience. 437 00:53:02,680 --> 00:53:04,200 MAN: Aw! 438 00:53:04,320 --> 00:53:05,520 (KATHARINE LAUGHS) 439 00:53:05,640 --> 00:53:07,760 MAN: Urgh! 440 00:53:09,560 --> 00:53:11,680 KATHARINE: We're going to be wearing half of Raine Island 441 00:53:11,800 --> 00:53:13,640 by the end of tonight! 442 00:53:15,880 --> 00:53:17,960 Helping the year's first hatchlings 443 00:53:18,080 --> 00:53:20,360 is a little easier. 444 00:53:20,480 --> 00:53:22,440 So, we'll take these ones down to the water's edge, 445 00:53:22,560 --> 00:53:25,800 so hopefully we'll see these turtles back here laying eggs 446 00:53:25,920 --> 00:53:27,520 in 30 years' time. 447 00:53:27,640 --> 00:53:30,240 With the help of this dedicated team, 448 00:53:30,360 --> 00:53:31,800 Raine Island's turtles 449 00:53:31,920 --> 00:53:34,200 might seem to have a good future. 450 00:53:39,120 --> 00:53:42,160 But research is revealing a hidden threat. 451 00:53:46,720 --> 00:53:49,440 The direct effects of climate change. 452 00:53:53,680 --> 00:53:55,080 Do you want to hold this 453 00:53:55,200 --> 00:53:57,800 against the flat part of the data logger? 454 00:53:57,920 --> 00:53:59,280 A developing turtle's sex 455 00:53:59,400 --> 00:54:02,560 is determined by the temperature of its nest. 456 00:54:03,600 --> 00:54:07,440 Higher temperatures produce female hatchlings. 457 00:54:09,360 --> 00:54:12,400 The temperature of the sand on Raine Island is now 458 00:54:12,520 --> 00:54:14,560 at a record high, 459 00:54:14,680 --> 00:54:19,400 so 99% of the turtles that hatch here are female. 460 00:54:20,880 --> 00:54:22,280 More alarmingly, 461 00:54:22,400 --> 00:54:24,520 we now know this has been the case 462 00:54:24,640 --> 00:54:27,000 for at least the last 20 years. 463 00:54:28,200 --> 00:54:32,440 You do the math - all females, no males. 464 00:54:32,560 --> 00:54:33,840 What's gonna happen? 465 00:54:33,960 --> 00:54:36,040 There's going to be a population crash 466 00:54:36,160 --> 00:54:38,200 and there'll be no more turtles. 467 00:54:41,480 --> 00:54:44,400 Work is under way to find solutions, 468 00:54:44,520 --> 00:54:46,960 but that's not their only problem. 469 00:54:48,360 --> 00:54:51,480 Not only are temperatures rising, 470 00:54:51,600 --> 00:54:54,240 sea levels are, too. 471 00:54:54,360 --> 00:54:57,520 Increasingly, high tides on Raine are flooding 472 00:54:57,640 --> 00:55:00,200 many of the nests from below... 473 00:55:03,040 --> 00:55:06,280 ...drowning the developing turtles before they hatch. 474 00:55:07,520 --> 00:55:09,800 It's really upsetting. You'll dig down 475 00:55:09,920 --> 00:55:11,600 to check to see success, 476 00:55:11,720 --> 00:55:14,280 and you get down to the nest 477 00:55:14,400 --> 00:55:16,640 and you're just pulling up dead eggs. 478 00:55:18,280 --> 00:55:19,640 To try and stop this happening, 479 00:55:19,760 --> 00:55:23,080 they have devised a heavy-duty solution. 480 00:55:27,800 --> 00:55:30,600 These machines have been shipped hundreds of miles 481 00:55:30,720 --> 00:55:34,560 from the Australian mainland to reshape the beach. 482 00:55:37,400 --> 00:55:39,400 They have already shifted sand 483 00:55:39,520 --> 00:55:42,920 that would fill 16 Olympic-sized swimming pools 484 00:55:43,040 --> 00:55:45,640 and doubled the number of safe nesting sites. 485 00:55:48,200 --> 00:55:50,640 The hope is that this will ensure 486 00:55:50,760 --> 00:55:52,800 that over five million more eggs 487 00:55:52,920 --> 00:55:55,040 will hatch in the next decade. 488 00:55:58,320 --> 00:56:01,040 But from then on, the future of Raine Island 489 00:56:01,160 --> 00:56:03,720 looks very uncertain. 490 00:56:04,800 --> 00:56:07,160 KATHARINE: At this stage, we think that we have 491 00:56:07,280 --> 00:56:09,080 until about 2050 until we start seeing 492 00:56:09,200 --> 00:56:12,080 massive impacts of sea level rise. 493 00:56:12,200 --> 00:56:14,560 It's crazy to think that, you know, 494 00:56:14,680 --> 00:56:16,200 the work that we do here, 495 00:56:16,320 --> 00:56:18,120 someone might not be doing this in 30 years' time 496 00:56:18,240 --> 00:56:20,200 cos there's no island to do it on. 497 00:56:23,960 --> 00:56:27,440 KERON: What sort of world is it going to be for my children 498 00:56:27,560 --> 00:56:29,120 and their children? 499 00:56:29,240 --> 00:56:32,440 Is there going to be anything for... 500 00:56:32,560 --> 00:56:36,880 ...for them, or is it...all in vain? 501 00:56:42,240 --> 00:56:46,520 We'll always be here fighting for Raine Island, the turtles, 502 00:56:46,640 --> 00:56:47,720 but we can't do it alone. 503 00:56:47,840 --> 00:56:50,600 We need government and big business to wake up 504 00:56:50,720 --> 00:56:52,680 and see what they're doing to the planet 505 00:56:52,800 --> 00:56:54,480 and get real. 506 00:57:00,280 --> 00:57:03,160 YOUNG DAVID: This little fellow is newly hatched from an egg 507 00:57:03,280 --> 00:57:05,160 which had been laid a month or so earlier, 508 00:57:05,280 --> 00:57:08,800 and he, too, is very anxious to get down to the sea. 509 00:57:12,640 --> 00:57:15,200 Having at last successfully reached the water, 510 00:57:15,320 --> 00:57:17,960 he's still got a great number of hazards to face 511 00:57:18,080 --> 00:57:19,480 before he grows up. 512 00:57:20,640 --> 00:57:23,120 DAVID: Little did I know then 513 00:57:23,240 --> 00:57:26,280 what hazards that little turtle would have to face, 514 00:57:26,400 --> 00:57:29,760 or the extraordinary lengths to which people would go 515 00:57:29,880 --> 00:57:32,360 to protect it and its island. 516 00:57:33,640 --> 00:57:36,800 In the 66 years since my visit, 517 00:57:36,920 --> 00:57:38,920 Raine Island has remained 518 00:57:39,040 --> 00:57:43,280 the most important green turtle nesting site on the planet. 519 00:57:43,400 --> 00:57:47,320 The question is, can it last another lifetime?