1 00:00:51,200 --> 00:00:55,200 Beneath the Yucatan Peninsula of Mexico... 2 00:00:56,760 --> 00:00:59,240 ..lies another world. 3 00:01:02,960 --> 00:01:05,480 A labyrinth of caves... 4 00:01:08,520 --> 00:01:12,240 ..carved by freshwater... 5 00:01:18,520 --> 00:01:22,120 ..and essential for life on Earth. 6 00:01:48,520 --> 00:01:54,320 Freshwater shapes the land and the creatures that live in it... 7 00:01:56,520 --> 00:01:59,120 ..in the most surprising ways. 8 00:02:08,320 --> 00:02:10,360 CHIRPING 9 00:02:15,000 --> 00:02:18,160 The rainforest of Costa Rica. 10 00:02:19,560 --> 00:02:24,000 As you might expect, it rains most days. 11 00:02:24,000 --> 00:02:26,000 RUMBLE OF THUNDER 12 00:02:26,000 --> 00:02:29,240 But it's only during the wet season 13 00:02:29,240 --> 00:02:32,520 that the rains become torrential. 14 00:02:41,040 --> 00:02:42,680 And with them... 15 00:02:43,720 --> 00:02:46,760 ..comes a most remarkable creature. 16 00:03:01,760 --> 00:03:04,960 Gliding tree frogs. 17 00:03:10,360 --> 00:03:13,160 Thousands drop in... 18 00:03:16,560 --> 00:03:20,480 ..to gather at this newly-formed pond. 19 00:03:27,760 --> 00:03:30,920 They all have an urgent need. 20 00:03:36,840 --> 00:03:38,480 To breed. 21 00:03:51,760 --> 00:03:55,240 This female needs to find a leaf 22 00:03:55,240 --> 00:03:57,440 and lay her eggs. 23 00:03:58,440 --> 00:04:00,200 FROGS CROAK 24 00:04:02,560 --> 00:04:06,520 The breeding frenzy will only last one day... 25 00:04:07,520 --> 00:04:10,480 ..so she needs to get a move on. 26 00:04:16,000 --> 00:04:18,760 There are lots of eager males. 27 00:04:24,880 --> 00:04:27,120 Nine for every female. 28 00:04:31,040 --> 00:04:35,680 And all are ready to spring into action. 29 00:04:41,280 --> 00:04:45,480 So, for her, getting a partner is no problem. 30 00:04:55,120 --> 00:04:58,200 But the other males are desperate. 31 00:05:18,840 --> 00:05:23,200 For this female, mating is rather chaotic. 32 00:05:34,560 --> 00:05:37,240 Things are getting out of hand. 33 00:05:45,440 --> 00:05:48,920 There is one way to deal with this. 34 00:05:55,000 --> 00:05:57,560 A few well-placed kicks... 35 00:06:00,520 --> 00:06:02,520 ..usually does the job. 36 00:06:15,000 --> 00:06:16,760 Problem solved. 37 00:06:16,760 --> 00:06:18,920 FROGS CROAK 38 00:06:21,040 --> 00:06:25,000 She and her partner can now finally mate... 39 00:06:26,520 --> 00:06:28,480 ..in relative peace. 40 00:06:59,000 --> 00:07:02,480 The eggs are positioned perfectly... 41 00:07:02,480 --> 00:07:05,480 ..directly overhanging the pond. 42 00:07:24,000 --> 00:07:28,720 This is the ideal nursery for tadpoles. 43 00:07:32,200 --> 00:07:35,200 For now, her work here is done. 44 00:07:36,280 --> 00:07:40,520 She'll be back next year when the heavy rains return. 45 00:07:44,480 --> 00:07:47,480 As quickly as freshwater appears... 46 00:07:50,000 --> 00:07:51,840 ..it can vanish. 47 00:08:04,000 --> 00:08:06,240 Southeast Sri Lanka. 48 00:08:06,240 --> 00:08:08,280 FLIES BUZZ 49 00:08:09,280 --> 00:08:12,000 It's the middle of the dry season. 50 00:08:15,360 --> 00:08:18,480 WIND HOWLS 51 00:08:28,600 --> 00:08:33,480 This is the only remaining water hole for miles around. 52 00:09:27,640 --> 00:09:29,720 DEER YELPS 53 00:09:32,200 --> 00:09:34,520 Mugger crocodiles - 54 00:09:34,520 --> 00:09:38,000 giants, five metres long. 55 00:09:40,920 --> 00:09:43,200 Dozens are hiding... 56 00:09:44,240 --> 00:09:46,480 ..beneath the surface. 57 00:09:54,520 --> 00:09:56,320 And others... 58 00:09:57,280 --> 00:09:59,240 ..are on their way. 59 00:10:17,320 --> 00:10:20,480 This male has been travelling for hours. 60 00:10:27,320 --> 00:10:30,840 The water hole is the only place where he has a chance 61 00:10:30,840 --> 00:10:32,560 to catch a deer. 62 00:10:44,200 --> 00:10:49,520 A single adult would be enough to feed him for the entire dry season. 63 00:11:00,560 --> 00:11:03,600 But hunting prey that knows you're here... 64 00:11:04,640 --> 00:11:07,760 ..requires something truly remarkable. 65 00:11:25,760 --> 00:11:27,520 He creates... 66 00:11:28,520 --> 00:11:30,200 ..a trap. 67 00:11:40,160 --> 00:11:43,200 He digs down into the mud... 68 00:11:56,560 --> 00:12:00,240 ..deep enough to hide beneath the vegetation. 69 00:12:17,520 --> 00:12:20,120 Perfect camouflage. 70 00:12:31,560 --> 00:12:35,520 He has built his trap right on the water's edge... 71 00:12:37,280 --> 00:12:41,840 ..so it's the first place that thirsty deer will come to drink. 72 00:13:05,320 --> 00:13:07,360 SQUAWKING 73 00:14:37,600 --> 00:14:40,800 These crocodiles have learned to exploit 74 00:14:40,800 --> 00:14:43,960 the deer's desperate need for freshwater. 75 00:14:56,760 --> 00:15:00,960 Freshwater transforms not only the lives of animals... 76 00:15:02,720 --> 00:15:05,240 ..but entire landscapes. 77 00:15:17,800 --> 00:15:21,480 Every year, over a trillion litres of water 78 00:15:21,480 --> 00:15:24,520 flow into the Kalahari Desert. 79 00:15:32,920 --> 00:15:37,520 It has travelled a thousand miles from where it fell as rain. 80 00:15:42,760 --> 00:15:44,600 And on arrival... 81 00:15:46,520 --> 00:15:49,320 ..it turns the Kalahari... 82 00:15:49,320 --> 00:15:52,520 ..into a vast oasis. 83 00:15:56,200 --> 00:15:58,200 SQUAWKING 84 00:16:01,520 --> 00:16:03,840 The Okavango Delta. 85 00:16:26,160 --> 00:16:30,000 These waters attract millions of animals. 86 00:16:38,800 --> 00:16:44,520 And for some, now is the perfect time to raise a family. 87 00:16:57,760 --> 00:16:59,600 A lily-trotter. 88 00:17:00,880 --> 00:17:02,880 CRACKING 89 00:17:06,040 --> 00:17:08,480 And he is a father... CHIRPING 90 00:17:08,480 --> 00:17:10,240 ..on duty. 91 00:17:20,920 --> 00:17:23,000 SQUAWKING 92 00:17:29,240 --> 00:17:31,360 He has not just one... 93 00:17:33,120 --> 00:17:36,920 ..but four newly-hatched chicks. 94 00:17:52,560 --> 00:17:56,960 They won't be able to fly for another six weeks... 95 00:18:00,000 --> 00:18:04,520 ..so, until then, he alone is their protector. 96 00:18:08,960 --> 00:18:11,040 CHIRPING 97 00:18:11,040 --> 00:18:15,240 Walking on water is not straightforward... 98 00:18:18,040 --> 00:18:22,680 ..so he must show them how to be a lily-trotter. 99 00:18:44,000 --> 00:18:48,000 The floodwaters make the perfect training ground. 100 00:19:04,160 --> 00:19:06,520 And in two weeks... 101 00:19:07,800 --> 00:19:11,200 ..his chicks not only double in size... 102 00:19:12,240 --> 00:19:14,800 ..they grow in confidence. 103 00:19:26,560 --> 00:19:30,520 But this is a dangerous place to stray. 104 00:19:37,240 --> 00:19:39,520 SQUAWKING 105 00:19:39,520 --> 00:19:41,960 He sounds the alarm, 106 00:19:41,960 --> 00:19:45,240 and his chicks instantly freeze. 107 00:19:47,240 --> 00:19:49,800 They can't yet fly to safety. 108 00:19:52,880 --> 00:19:56,240 But there is one thing he can do to protect them. 109 00:19:56,240 --> 00:19:58,480 SQUAWKING 110 00:19:58,480 --> 00:20:00,760 And it's risky. 111 00:20:00,760 --> 00:20:02,560 SQUAWKING 112 00:20:03,600 --> 00:20:06,760 Get close enough to distract... 113 00:20:08,040 --> 00:20:10,760 ..and hopefully divert the crocodile. 114 00:20:14,080 --> 00:20:16,080 SQUAWKING 115 00:20:29,960 --> 00:20:32,000 SQUAWKING 116 00:20:41,240 --> 00:20:43,240 Mission accomplished. 117 00:20:55,960 --> 00:20:58,000 SQUAWKING 118 00:20:58,000 --> 00:21:00,520 He signals the all clear. 119 00:21:13,520 --> 00:21:16,000 But one chick is missing. 120 00:21:18,520 --> 00:21:20,560 SQUAWKING 121 00:21:39,560 --> 00:21:42,000 His calls... SQUAWKING 122 00:21:42,000 --> 00:21:44,000 ..go unanswered. 123 00:22:37,600 --> 00:22:41,160 A little bedraggled but alive and well. 124 00:22:41,160 --> 00:22:43,280 CHIRPING 125 00:22:47,440 --> 00:22:50,760 His chick just hadn't heard his call. 126 00:22:52,240 --> 00:22:54,480 And when danger threatens, 127 00:22:54,480 --> 00:22:57,760 its always better to be safe than sorry. 128 00:23:26,040 --> 00:23:29,040 He's brought his chicks, all four of them, 129 00:23:29,040 --> 00:23:31,720 to the verge of independence. 130 00:23:45,560 --> 00:23:48,240 Whilst lily-trotters are well adapted 131 00:23:48,240 --> 00:23:50,640 to life in this flooded world... 132 00:23:50,640 --> 00:23:52,720 PANTING 133 00:23:53,760 --> 00:23:57,680 ..these residents of the delta are not. 134 00:24:02,760 --> 00:24:04,760 HIGH-PITCHED BARKING 135 00:24:08,960 --> 00:24:11,520 African painted dogs. 136 00:24:14,800 --> 00:24:18,520 Normally, they are remarkably successful hunters. 137 00:24:19,560 --> 00:24:23,840 But this pack of five hasn't eaten in days. 138 00:24:23,840 --> 00:24:25,880 PANTING 139 00:24:29,520 --> 00:24:32,880 Finding prey isn't the problem. 140 00:24:39,800 --> 00:24:44,200 This herd of lechwe is only a few hundred metres away. 141 00:24:48,960 --> 00:24:52,520 But between them is deep water. 142 00:25:06,480 --> 00:25:08,560 HIGH-PITCHED WHINING 143 00:25:15,960 --> 00:25:17,560 GRUNTING 144 00:25:17,560 --> 00:25:19,520 HIGH-PITCHED SQUEALS 145 00:25:28,240 --> 00:25:31,240 It's not safe to cross here. 146 00:26:55,160 --> 00:26:56,640 LECHWE BARKS 147 00:27:17,040 --> 00:27:21,720 On dry land, the dogs can run at over 40mph. 148 00:27:28,040 --> 00:27:32,960 But when threatened, lechwe always seek the safety of water. 149 00:27:38,800 --> 00:27:42,200 With their splayed hooves and long hind legs, 150 00:27:42,200 --> 00:27:44,760 they can power their way through the water. 151 00:27:46,480 --> 00:27:48,880 The dogs can't. 152 00:28:12,560 --> 00:28:16,760 The pack won't be able to outswim the lechwe. 153 00:28:16,760 --> 00:28:18,840 PANTING 154 00:28:19,800 --> 00:28:22,200 But they do have a strategy. 155 00:28:43,280 --> 00:28:47,520 The dogs drive the lechwe to where they have the advantage. 156 00:28:53,240 --> 00:28:55,960 Back towards dry land. 157 00:28:59,760 --> 00:29:03,520 Now the pack can regain lost ground. 158 00:29:51,120 --> 00:29:56,480 Success today, but tomorrow the pack will need to hunt again. 159 00:30:00,240 --> 00:30:02,000 In the Okavango, 160 00:30:02,000 --> 00:30:07,480 animals must always adapt to the coming and going of freshwater. 161 00:30:12,280 --> 00:30:17,280 But there are a few rare places, as here in Lake Malawi, 162 00:30:17,280 --> 00:30:21,240 where freshwater has lain for millions of years. 163 00:30:23,880 --> 00:30:27,040 And that has enabled life to evolve 164 00:30:27,040 --> 00:30:31,240 into a dazzling diversity of species. 165 00:30:37,960 --> 00:30:41,480 There are over a thousand different kinds of fish here... 166 00:30:42,760 --> 00:30:45,520 ..more than any other lake on Earth. 167 00:30:56,560 --> 00:31:00,760 Competition in these waters is intense. 168 00:31:23,400 --> 00:31:27,760 Meet Nimbochromis livingstonii. 169 00:31:31,000 --> 00:31:33,360 A master of deception 170 00:31:33,360 --> 00:31:37,480 that tricks other fish into thinking it's dead. 171 00:31:41,560 --> 00:31:46,000 Its mottled colouration mimics decaying flesh. 172 00:31:51,960 --> 00:31:54,400 But to appear dead... 173 00:31:57,520 --> 00:31:59,400 ..one must at least... 174 00:32:00,400 --> 00:32:02,440 ..act dead. 175 00:32:06,000 --> 00:32:09,120 This juvenile is fooling no-one. 176 00:32:14,400 --> 00:32:18,520 Perhaps faking his death will be more believable. 177 00:32:44,480 --> 00:32:46,120 Blown it. 178 00:32:56,560 --> 00:32:59,520 A more subtle performance will be needed. 179 00:33:12,760 --> 00:33:15,360 This is more convincing. 180 00:33:27,920 --> 00:33:30,760 But his aim must be better than that. 181 00:33:38,120 --> 00:33:39,680 Nearly. 182 00:33:47,280 --> 00:33:50,080 It seems he's overstayed his welcome. 183 00:34:23,160 --> 00:34:25,440 In a final effort... 184 00:34:25,440 --> 00:34:28,760 ..he appears to even hold his breath. 185 00:34:49,520 --> 00:34:51,960 Success at last. 186 00:35:11,840 --> 00:35:16,000 All it took was a million years of evolution... 187 00:35:24,800 --> 00:35:29,480 ..and the unique stability of this ancient lake. 188 00:35:38,320 --> 00:35:42,160 Off the western coast of Equatorial Africa 189 00:35:42,160 --> 00:35:46,240 lies the volcanic island of Bioko. 190 00:35:46,240 --> 00:35:48,600 RUMBLE OF THUNDER 191 00:35:56,600 --> 00:36:00,800 Freshwater here has a turbulent nature. 192 00:36:36,520 --> 00:36:40,000 Few venture into such waters, 193 00:36:40,000 --> 00:36:44,480 but for those that do, there can be great rewards. 194 00:36:47,560 --> 00:36:50,680 After months feeding and growing out at sea, 195 00:36:50,680 --> 00:36:53,760 these gobies are ready to breed. 196 00:36:57,040 --> 00:37:00,200 And the safest place to lay their eggs 197 00:37:00,200 --> 00:37:03,960 is somewhere that ocean predators can't reach. 198 00:37:06,520 --> 00:37:09,000 The top of this waterfall. 199 00:37:14,800 --> 00:37:18,200 Surely an impossible journey for a fish. 200 00:37:22,280 --> 00:37:27,640 But over the coming days, the gobies transform themselves. 201 00:37:30,760 --> 00:37:32,600 They change colour. 202 00:37:37,560 --> 00:37:43,520 Their mouth rotates and acts like a kind of suction cup... 203 00:37:45,000 --> 00:37:47,480 ..which they will certainly need. 204 00:37:53,000 --> 00:37:57,040 Because the only way...is up. 205 00:38:18,240 --> 00:38:21,520 It is 30 metres to the top. 206 00:38:28,000 --> 00:38:31,520 They are only an inch long. 207 00:38:34,560 --> 00:38:38,960 This is the equivalent of a human being scaling a waterfall 208 00:38:38,960 --> 00:38:41,000 over a mile high. 209 00:38:50,520 --> 00:38:53,240 Millions attempt the climb... 210 00:38:54,480 --> 00:38:58,160 ..but less than 1% will make it. 211 00:39:07,800 --> 00:39:11,320 This goby has been climbing for days. 212 00:39:19,720 --> 00:39:21,480 Made it! 213 00:39:25,880 --> 00:39:30,240 Those that reach the top can now prepare to breed. 214 00:39:33,520 --> 00:39:38,760 And when the time comes, their young will be washed back out to sea. 215 00:39:59,800 --> 00:40:02,560 The extraordinary power of flowing water 216 00:40:02,560 --> 00:40:06,000 makes it our planet's greatest architect. 217 00:40:26,560 --> 00:40:31,000 This may look like the surface of an alien planet... 218 00:40:44,080 --> 00:40:49,640 ..but these strange patterns are channels of freshwater... 219 00:40:51,840 --> 00:40:54,240 .flowing towards the sea. 220 00:41:08,480 --> 00:41:11,520 For 3.8 billion years, 221 00:41:11,520 --> 00:41:14,360 ever since the first rains fell... 222 00:41:15,840 --> 00:41:19,120 ..freshwater has been making this journey. 223 00:41:34,840 --> 00:41:39,520 But today, two thirds of our world's great rivers 224 00:41:39,520 --> 00:41:42,160 no longer reach the sea. 225 00:41:54,360 --> 00:41:58,200 CREAKING 226 00:42:14,560 --> 00:42:18,760 There is a finite amount of freshwater on Earth... 227 00:42:31,040 --> 00:42:34,920 ..so humans have devised extraordinary means 228 00:42:34,920 --> 00:42:40,520 to ensure that it is always available to meet our every demand. 229 00:42:50,760 --> 00:42:54,000 We now control freshwater... 230 00:42:55,520 --> 00:42:57,760 ..on a colossal scale. 231 00:43:02,560 --> 00:43:05,480 The largest irrigation system on Earth 232 00:43:05,480 --> 00:43:08,920 has been built here in Pakistan. 233 00:43:10,440 --> 00:43:14,480 HORNS BLARE 234 00:43:18,000 --> 00:43:21,840 A vast network of dams and canals... 235 00:43:24,560 --> 00:43:29,000 ..that diverts and drains the great Indus River. 236 00:43:35,040 --> 00:43:39,760 It's used to irrigate an area the size of England. 237 00:43:44,520 --> 00:43:47,360 This man-made freshwater world 238 00:43:47,360 --> 00:43:50,200 provides water and a livelihood 239 00:43:50,200 --> 00:43:52,480 for millions of people... 240 00:43:52,480 --> 00:43:54,560 LAUGHTER 241 00:43:56,640 --> 00:44:00,520 CHATTER 242 00:44:00,520 --> 00:44:04,240 ..but at a cost to the natural world. 243 00:44:04,240 --> 00:44:07,840 CHATTER 244 00:44:17,040 --> 00:44:22,480 A rare creature has become stranded in this irrigation canal. 245 00:44:26,000 --> 00:44:28,960 And the water will soon be gone, 246 00:44:28,960 --> 00:44:32,520 used to supply the surrounding land. 247 00:44:38,800 --> 00:44:43,760 Endangered, they number fewer than 2,000 individuals. 248 00:44:49,240 --> 00:44:51,840 An Indus river dolphin. 249 00:44:53,400 --> 00:44:57,560 CHATTER, YELLING 250 00:45:05,800 --> 00:45:11,520 This female dolphin is 150 miles from the main river. 251 00:45:15,200 --> 00:45:17,920 She can't return on her own, 252 00:45:17,920 --> 00:45:23,000 so the only option is for this rescue team to take her. 253 00:45:23,000 --> 00:45:27,120 CHATTER 254 00:45:34,960 --> 00:45:38,040 CHATTER CONTINUES 255 00:45:47,040 --> 00:45:50,800 Out of water, she cannot survive for long. 256 00:45:50,800 --> 00:45:54,840 CHATTER 257 00:45:57,560 --> 00:46:00,920 The journey back to the river will take hours. 258 00:46:00,920 --> 00:46:05,640 CHATTER 259 00:46:10,560 --> 00:46:15,200 Her life now depends on these people. 260 00:46:36,520 --> 00:46:39,920 SIREN WAILS 261 00:47:33,640 --> 00:47:39,120 CHATTER 262 00:48:06,280 --> 00:48:12,040 Nearly 30 dolphins had to be rescued in one month alone. 263 00:48:42,280 --> 00:48:46,760 Freshwater is not only a resource for humans. 264 00:48:52,800 --> 00:48:57,560 It is the home for countless species 265 00:48:57,560 --> 00:49:02,680 that simply cannot survive without it. 266 00:49:21,520 --> 00:49:25,240 Freshwater is the lifeblood 267 00:49:25,240 --> 00:49:27,720 of Planet Earth. 268 00:49:49,560 --> 00:49:54,040 To film the story of the most endangered freshwater dolphin, 269 00:49:54,040 --> 00:49:58,800 the Planet Earth team joined the world's leading expert - Uzma Khan. 270 00:49:58,800 --> 00:50:02,960 The first time I saw Indus dolphin, I was just amazed. 271 00:50:02,960 --> 00:50:05,040 It's a beautiful creature, you know, 272 00:50:05,040 --> 00:50:07,680 it's like love at first sight. It's so unique. 273 00:50:09,280 --> 00:50:13,280 Uzma has been studying the last remaining population 274 00:50:13,280 --> 00:50:15,240 for over 20 years. 275 00:50:16,800 --> 00:50:20,480 There's a dolphin that surfaced just right there. 276 00:50:20,480 --> 00:50:25,080 Indus river dolphin can only live in freshwater. 277 00:50:25,080 --> 00:50:28,280 It is only found in Pakistan and nowhere else. 278 00:50:28,280 --> 00:50:32,560 And we only have about 2,000 of them left in the Indus River. 279 00:50:32,560 --> 00:50:36,680 So, you know, each individual is special. 280 00:50:38,840 --> 00:50:43,760 Following the dolphins in the murky water is extremely challenging. 281 00:50:44,800 --> 00:50:47,840 They only surface for a split second 282 00:50:47,840 --> 00:50:51,600 and that makes protecting them difficult, too. 283 00:50:51,600 --> 00:50:57,520 Their greatest threat is becoming trapped in the irrigation canals. 284 00:50:58,520 --> 00:51:01,280 But Uzma may have a solution, 285 00:51:01,280 --> 00:51:04,520 and teams up with a rescue unit... 286 00:51:05,560 --> 00:51:09,200 ..to attempt something never done before. 287 00:51:11,640 --> 00:51:14,520 This is the first time we'll be putting satellite tags 288 00:51:14,520 --> 00:51:16,560 on river dolphins in Asia. 289 00:51:16,560 --> 00:51:19,600 Sensors has not been tested on this species, 290 00:51:19,600 --> 00:51:22,880 there's a little bit of anxiety, but if they work, 291 00:51:22,880 --> 00:51:25,840 then it's going to be a breakthrough for conservation. 292 00:51:25,840 --> 00:51:28,920 SIREN WAILS 293 00:51:28,920 --> 00:51:33,920 Uzma has been developing a suitable tag for over ten years 294 00:51:33,920 --> 00:51:38,040 and hopes it will help her collect critical data 295 00:51:38,040 --> 00:51:41,520 on how the dolphins are moving through the dams and canals. 296 00:51:42,800 --> 00:51:47,720 But in order to tag, she will first need a successful rescue. 297 00:51:47,720 --> 00:51:51,880 CHATTER 298 00:51:57,600 --> 00:52:02,080 I'm usually very concerned when a rescue is happening. 299 00:52:12,080 --> 00:52:14,560 You know, the divers, they are very experienced, 300 00:52:14,560 --> 00:52:17,320 but a part of me is always very worried. 301 00:52:18,840 --> 00:52:22,000 They are wild animals that have never been handled. 302 00:52:24,000 --> 00:52:27,040 It's really quite a risky thing that they're undertaking here. 303 00:52:27,040 --> 00:52:29,320 There's a good chance the dolphin might die. 304 00:52:29,320 --> 00:52:32,040 But, of course, they're balancing that against the fact 305 00:52:32,040 --> 00:52:34,520 that they definitely will die if they stay in here, 306 00:52:34,520 --> 00:52:36,520 so it's a risk they have to take. 307 00:52:42,000 --> 00:52:45,960 CHATTER 308 00:52:52,800 --> 00:52:55,680 Have they got the dolphin? Yeah, I think so. They've got it. 309 00:52:59,000 --> 00:53:01,760 Now speed is key. 310 00:53:04,240 --> 00:53:07,960 CHATTER 311 00:53:11,040 --> 00:53:14,520 We're now bombing across the field on the way to the release site, 312 00:53:14,520 --> 00:53:17,040 and I think Uzma went ahead of us, so I'm really hopeful 313 00:53:17,040 --> 00:53:19,520 that she'll get her opportunity to tag the dolphin. 314 00:53:19,520 --> 00:53:23,280 SIREN WAILS 315 00:53:23,280 --> 00:53:27,520 But rescue missions don't always go to plan. 316 00:53:28,520 --> 00:53:30,320 LOUD RELEASE OF AIR 317 00:53:37,840 --> 00:53:39,520 A puncture. 318 00:53:47,080 --> 00:53:50,960 The dolphin is quickly moved to the film crew's truck. 319 00:54:00,160 --> 00:54:02,200 ANXIOUS CHATTER 320 00:54:11,880 --> 00:54:14,600 But with no roof for shelter, 321 00:54:14,600 --> 00:54:18,240 the dolphin is at greater risk of dehydration. 322 00:54:18,240 --> 00:54:20,840 The stakes are high, even right now. 323 00:54:21,880 --> 00:54:24,520 It's a cute little animal and we don't want it to die. 324 00:54:29,960 --> 00:54:33,600 The team re-route to the closest release site. 325 00:54:35,760 --> 00:54:37,840 There can be no more delay. 326 00:54:39,000 --> 00:54:41,480 Uzma calls off the tagging. 327 00:55:00,040 --> 00:55:02,720 It's unfortunate because we were all prepared, 328 00:55:02,720 --> 00:55:05,800 we were very excited since morning, all geared up, 329 00:55:05,800 --> 00:55:10,480 but hopefully we'll get an opportunity to tag the next rescue. 330 00:55:21,280 --> 00:55:25,720 A few days later, Uzma finally gets her chance. 331 00:55:31,800 --> 00:55:34,840 It's a very exciting day for us. 332 00:55:34,840 --> 00:55:36,800 It's OK. 333 00:55:36,800 --> 00:55:40,720 The moment that we have been waiting for, over ten years. 334 00:55:41,680 --> 00:55:43,560 Just stay calm. 335 00:55:48,720 --> 00:55:50,720 OK, it's good to go. 336 00:55:54,600 --> 00:55:56,800 Congratulations. 337 00:55:56,800 --> 00:55:58,880 Well done. 338 00:56:03,200 --> 00:56:06,800 I am very happy, very happy. 339 00:56:06,800 --> 00:56:09,360 I think it's a great accomplishment. 340 00:56:11,520 --> 00:56:14,240 It's the happiest moment of my life. 341 00:56:15,920 --> 00:56:18,800 APPLAUSE 342 00:56:21,000 --> 00:56:26,760 Within a few weeks, the tags begin to reveal some new insights. 343 00:56:28,840 --> 00:56:32,640 They are moving quite a lot, which we never expected. 344 00:56:32,640 --> 00:56:37,800 So one of the dolphins actually went about 46km upstream 345 00:56:37,800 --> 00:56:41,360 from the release site, and the other thing is that we thought 346 00:56:41,360 --> 00:56:43,800 that they will stay in the main river stream, 347 00:56:43,800 --> 00:56:47,720 but they are using side channels. It is extremely interesting. 348 00:56:48,800 --> 00:56:51,720 Tracking the movement of the tagged dolphins 349 00:56:51,720 --> 00:56:54,040 will help Uzma better understand 350 00:56:54,040 --> 00:56:57,000 when and where they become trapped... 351 00:56:58,280 --> 00:57:03,200 ..helping safeguard the future of this most endangered animal. 352 00:57:09,240 --> 00:57:11,000 Next time... 353 00:57:12,080 --> 00:57:13,720 ..forests. 354 00:57:15,320 --> 00:57:17,560 A hidden world... 355 00:57:17,560 --> 00:57:19,520 CHIRPING 356 00:57:19,520 --> 00:57:22,960 ..where lives are intimately entwined... 357 00:57:24,800 --> 00:57:27,840 ..in the most unexpected ways. 358 00:57:33,560 --> 00:57:37,760 Habitat Explorer brings animals and their habitats to life. 359 00:57:37,760 --> 00:57:41,320 Explore this free interactive and make origami animals. 360 00:57:41,320 --> 00:57:45,160 Go to bbc.co.uk/planetearth3 361 00:57:45,160 --> 00:57:47,600 and follow the links to the Open University. 362 00:57:47,600 --> 00:57:50,040 Or to order a free printed version, 363 00:57:50,040 --> 00:57:53,200 visit the website or call the number on the screen.