1 00:00:50,320 --> 00:00:54,760 Beneath the Yucatan Peninsula of Mexico... 2 00:00:56,280 --> 00:00:58,760 ..lies another world. 3 00:01:02,520 --> 00:01:05,040 A labyrinth of caves... 4 00:01:08,040 --> 00:01:11,760 ..carved by freshwater... 5 00:01:18,040 --> 00:01:21,640 ..and essential for life on Earth. 6 00:01:48,040 --> 00:01:53,840 Freshwater shapes the land and the creatures that live in it... 7 00:01:56,040 --> 00:01:58,680 ..in the most surprising ways. 8 00:02:07,840 --> 00:02:09,880 CHIRPING 9 00:02:14,520 --> 00:02:17,680 The rainforest of Costa Rica. 10 00:02:19,040 --> 00:02:23,520 As you might expect, it rains most days. 11 00:02:23,520 --> 00:02:25,520 RUMBLE OF THUNDER 12 00:02:25,520 --> 00:02:28,760 But it's only during the wet season 13 00:02:28,760 --> 00:02:32,040 that the rains become torrential. 14 00:02:40,520 --> 00:02:42,240 And with them... 15 00:02:43,240 --> 00:02:46,280 ..comes a most remarkable creature. 16 00:03:01,280 --> 00:03:04,480 Gliding tree frogs. 17 00:03:09,880 --> 00:03:12,680 Thousands drop in... 18 00:03:16,040 --> 00:03:20,040 ..to gather at this newly-formed pond. 19 00:03:27,280 --> 00:03:30,440 They all have an urgent need. 20 00:03:36,360 --> 00:03:38,040 To breed. 21 00:03:51,280 --> 00:03:54,760 This female needs to find a leaf 22 00:03:54,760 --> 00:03:56,960 and lay her eggs. 23 00:03:57,960 --> 00:03:59,760 FROGS CROAK 24 00:04:02,040 --> 00:04:06,040 The breeding frenzy will only last one day... 25 00:04:07,040 --> 00:04:10,040 ..so she needs to get a move on. 26 00:04:15,520 --> 00:04:18,280 There are lots of eager males. 27 00:04:24,400 --> 00:04:26,680 Nine for every female. 28 00:04:30,520 --> 00:04:35,200 And all are ready to spring into action. 29 00:04:40,760 --> 00:04:45,040 So, for her, getting a partner is no problem. 30 00:04:54,640 --> 00:04:57,760 But the other males are desperate. 31 00:05:18,320 --> 00:05:22,760 For this female, mating is rather chaotic. 32 00:05:34,080 --> 00:05:36,760 Things are getting out of hand. 33 00:05:45,000 --> 00:05:48,440 There is one way to deal with this. 34 00:05:54,520 --> 00:05:57,080 A few well-placed kicks... 35 00:06:00,040 --> 00:06:02,040 ..usually does the job. 36 00:06:14,520 --> 00:06:16,280 Problem solved. 37 00:06:16,280 --> 00:06:18,440 FROGS CROAK 38 00:06:20,520 --> 00:06:24,520 She and her partner can now finally mate... 39 00:06:26,040 --> 00:06:28,040 ..in relative peace. 40 00:06:58,520 --> 00:07:02,040 The eggs are positioned perfectly... 41 00:07:02,040 --> 00:07:05,040 ..directly overhanging the pond. 42 00:07:23,480 --> 00:07:28,280 This is the ideal nursery for tadpoles. 43 00:07:31,760 --> 00:07:34,760 For now, her work here is done. 44 00:07:35,760 --> 00:07:40,040 She'll be back next year when the heavy rains return. 45 00:07:44,040 --> 00:07:47,040 As quickly as freshwater appears... 46 00:07:49,520 --> 00:07:51,360 ..it can vanish. 47 00:08:03,520 --> 00:08:05,800 Southeast Sri Lanka. 48 00:08:05,800 --> 00:08:07,840 FLIES BUZZ 49 00:08:08,840 --> 00:08:11,520 It's the middle of the dry season. 50 00:08:14,920 --> 00:08:18,040 WIND HOWLS 51 00:08:28,040 --> 00:08:33,040 This is the only remaining water hole for miles around. 52 00:09:27,200 --> 00:09:29,240 DEER YELPS 53 00:09:31,720 --> 00:09:34,040 Mugger crocodiles - 54 00:09:34,040 --> 00:09:37,520 giants, five metres long. 55 00:09:40,440 --> 00:09:42,760 Dozens are hiding... 56 00:09:43,760 --> 00:09:46,040 ..beneath the surface. 57 00:09:54,040 --> 00:09:55,840 And others... 58 00:09:56,840 --> 00:09:58,760 ..are on their way. 59 00:10:16,760 --> 00:10:20,040 This male has been travelling for hours. 60 00:10:26,760 --> 00:10:30,360 The water hole is the only place where he has a chance 61 00:10:30,360 --> 00:10:32,120 to catch a deer. 62 00:10:43,680 --> 00:10:49,040 A single adult would be enough to feed him for the entire dry season. 63 00:11:00,040 --> 00:11:03,120 But hunting prey that knows you're here... 64 00:11:04,120 --> 00:11:07,280 ..requires something truly remarkable. 65 00:11:25,280 --> 00:11:27,040 He creates... 66 00:11:28,040 --> 00:11:29,760 ..a trap. 67 00:11:39,720 --> 00:11:42,760 He digs down into the mud... 68 00:11:56,040 --> 00:11:59,760 ..deep enough to hide beneath the vegetation. 69 00:12:17,040 --> 00:12:19,680 Perfect camouflage. 70 00:12:31,040 --> 00:12:35,040 He has built his trap right on the water's edge... 71 00:12:36,760 --> 00:12:41,360 ..so it's the first place that thirsty deer will come to drink. 72 00:13:04,840 --> 00:13:06,880 SQUAWKING 73 00:14:37,040 --> 00:14:40,280 These crocodiles have learned to exploit 74 00:14:40,280 --> 00:14:43,520 the deer's desperate need for freshwater. 75 00:14:56,280 --> 00:15:00,520 Freshwater transforms not only the lives of animals... 76 00:15:02,280 --> 00:15:04,760 ..but entire landscapes. 77 00:15:17,280 --> 00:15:21,040 Every year, over a trillion litres of water 78 00:15:21,040 --> 00:15:24,040 flow into the Kalahari Desert. 79 00:15:32,360 --> 00:15:37,040 It has travelled a thousand miles from where it fell as rain. 80 00:15:42,280 --> 00:15:44,160 And on arrival... 81 00:15:46,040 --> 00:15:48,880 ..it turns the Kalahari... 82 00:15:48,880 --> 00:15:52,040 ..into a vast oasis. 83 00:15:55,720 --> 00:15:57,760 SQUAWKING 84 00:16:01,040 --> 00:16:03,360 The Okavango Delta. 85 00:16:25,600 --> 00:16:29,520 These waters attract millions of animals. 86 00:16:38,280 --> 00:16:44,040 And for some, now is the perfect time to raise a family. 87 00:16:57,280 --> 00:16:59,120 A lily-trotter. 88 00:17:00,400 --> 00:17:02,440 CRACKING 89 00:17:05,520 --> 00:17:08,040 And he is a father... 90 00:17:05,520 --> 00:17:08,040 CHIRPING 91 00:17:08,040 --> 00:17:09,760 ..on duty. 92 00:17:20,480 --> 00:17:22,520 SQUAWKING 93 00:17:28,760 --> 00:17:30,880 He has not just one... 94 00:17:32,640 --> 00:17:36,440 ..but four newly-hatched chicks. 95 00:17:52,040 --> 00:17:56,520 They won't be able to fly for another six weeks... 96 00:17:59,480 --> 00:18:04,040 ..so, until then, he alone is their protector. 97 00:18:08,480 --> 00:18:10,520 CHIRPING 98 00:18:10,520 --> 00:18:14,760 Walking on water is not straightforward... 99 00:18:17,520 --> 00:18:22,240 ..so he must show them how to be a lily-trotter. 100 00:18:43,520 --> 00:18:47,520 The floodwaters make the perfect training ground. 101 00:19:03,680 --> 00:19:06,040 And in two weeks... 102 00:19:07,280 --> 00:19:10,760 ..his chicks not only double in size... 103 00:19:11,760 --> 00:19:14,360 ..they grow in confidence. 104 00:19:26,040 --> 00:19:30,040 But this is a dangerous place to stray. 105 00:19:36,760 --> 00:19:39,040 SQUAWKING 106 00:19:39,040 --> 00:19:41,480 He sounds the alarm, 107 00:19:41,480 --> 00:19:44,760 and his chicks instantly freeze. 108 00:19:46,760 --> 00:19:49,360 They can't yet fly to safety. 109 00:19:52,360 --> 00:19:55,760 But there is one thing he can do to protect them. 110 00:19:55,760 --> 00:19:58,040 SQUAWKING 111 00:19:58,040 --> 00:20:00,280 And it's risky. 112 00:20:00,280 --> 00:20:02,120 SQUAWKING 113 00:20:03,120 --> 00:20:06,280 Get close enough to distract... 114 00:20:07,520 --> 00:20:10,280 ..and hopefully divert the crocodile. 115 00:20:13,640 --> 00:20:15,600 SQUAWKING 116 00:20:29,480 --> 00:20:31,520 SQUAWKING 117 00:20:40,760 --> 00:20:42,760 Mission accomplished. 118 00:20:55,480 --> 00:20:57,520 SQUAWKING 119 00:20:57,520 --> 00:21:00,040 He signals the all clear. 120 00:21:13,040 --> 00:21:15,520 But one chick is missing. 121 00:21:18,040 --> 00:21:20,080 SQUAWKING 122 00:21:39,040 --> 00:21:41,520 His calls... 123 00:21:39,040 --> 00:21:41,520 SQUAWKING 124 00:21:41,520 --> 00:21:43,520 ..go unanswered. 125 00:22:37,040 --> 00:22:40,680 A little bedraggled but alive and well. 126 00:22:40,680 --> 00:22:42,800 CHIRPING 127 00:22:46,880 --> 00:22:50,280 His chick just hadn't heard his call. 128 00:22:51,760 --> 00:22:53,920 And when danger threatens, 129 00:22:53,920 --> 00:22:57,280 its always better to be safe than sorry. 130 00:23:25,520 --> 00:23:28,560 He's brought his chicks, all four of them, 131 00:23:28,560 --> 00:23:31,280 to the verge of independence. 132 00:23:45,040 --> 00:23:47,760 Whilst lily-trotters are well adapted 133 00:23:47,760 --> 00:23:50,200 to life in this flooded world... 134 00:23:50,200 --> 00:23:52,240 PANTING 135 00:23:53,240 --> 00:23:57,200 ..these residents of the delta are not. 136 00:24:02,280 --> 00:24:04,320 HIGH-PITCHED BARKING 137 00:24:08,520 --> 00:24:11,040 African painted dogs. 138 00:24:14,280 --> 00:24:18,040 Normally, they are remarkably successful hunters. 139 00:24:19,040 --> 00:24:23,360 But this pack of five hasn't eaten in days. 140 00:24:23,360 --> 00:24:25,400 PANTING 141 00:24:29,040 --> 00:24:32,360 Finding prey isn't the problem. 142 00:24:39,280 --> 00:24:43,760 This herd of lechwe is only a few hundred metres away. 143 00:24:48,520 --> 00:24:52,040 But between them is deep water. 144 00:25:06,040 --> 00:25:08,080 HIGH-PITCHED WHINING 145 00:25:15,480 --> 00:25:17,120 GRUNTING 146 00:25:17,120 --> 00:25:19,080 HIGH-PITCHED SQUEALS 147 00:25:27,800 --> 00:25:30,760 It's not safe to cross here. 148 00:26:54,680 --> 00:26:56,160 LECHWE BARKS 149 00:27:16,520 --> 00:27:21,280 On dry land, the dogs can run at over 40mph. 150 00:27:27,520 --> 00:27:32,520 But when threatened, lechwe always seek the safety of water. 151 00:27:38,280 --> 00:27:41,640 With their splayed hooves and long hind legs, 152 00:27:41,640 --> 00:27:44,280 they can power their way through the water. 153 00:27:46,040 --> 00:27:48,400 The dogs can't. 154 00:28:12,040 --> 00:28:16,320 The pack won't be able to outswim the lechwe. 155 00:28:16,320 --> 00:28:18,360 PANTING 156 00:28:19,360 --> 00:28:21,760 But they do have a strategy. 157 00:28:42,760 --> 00:28:47,040 The dogs drive the lechwe to where they have the advantage. 158 00:28:52,760 --> 00:28:55,480 Back towards dry land. 159 00:28:59,280 --> 00:29:03,040 Now the pack can regain lost ground. 160 00:29:50,640 --> 00:29:56,040 Success today, but tomorrow the pack will need to hunt again. 161 00:29:59,760 --> 00:30:01,480 In the Okavango, 162 00:30:01,480 --> 00:30:07,040 animals must always adapt to the coming and going of freshwater. 163 00:30:11,760 --> 00:30:16,760 But there are a few rare places, as here in Lake Malawi, 164 00:30:16,760 --> 00:30:20,760 where freshwater has lain for millions of years. 165 00:30:23,360 --> 00:30:26,520 And that has enabled life to evolve 166 00:30:26,520 --> 00:30:30,760 into a dazzling diversity of species. 167 00:30:37,440 --> 00:30:41,040 There are over a thousand different kinds of fish here... 168 00:30:42,280 --> 00:30:45,040 ..more than any other lake on Earth. 169 00:30:56,040 --> 00:31:00,280 Competition in these waters is intense. 170 00:31:22,920 --> 00:31:27,280 Meet Nimbochromis livingstonii. 171 00:31:30,520 --> 00:31:32,800 A master of deception 172 00:31:32,800 --> 00:31:37,040 that tricks other fish into thinking it's dead. 173 00:31:41,040 --> 00:31:45,520 Its mottled colouration mimics decaying flesh. 174 00:31:51,520 --> 00:31:53,920 But to appear dead... 175 00:31:57,040 --> 00:31:58,920 ..one must at least... 176 00:31:59,920 --> 00:32:01,960 ..act dead. 177 00:32:05,520 --> 00:32:08,680 This juvenile is fooling no-one. 178 00:32:13,840 --> 00:32:18,040 Perhaps faking his death will be more believable. 179 00:32:44,040 --> 00:32:45,680 Blown it. 180 00:32:56,040 --> 00:32:59,040 A more subtle performance will be needed. 181 00:33:12,280 --> 00:33:14,880 This is more convincing. 182 00:33:27,400 --> 00:33:30,280 But his aim must be better than that. 183 00:33:37,680 --> 00:33:39,200 Nearly. 184 00:33:46,760 --> 00:33:49,600 It seems he's overstayed his welcome. 185 00:34:22,680 --> 00:34:24,880 In a final effort... 186 00:34:24,880 --> 00:34:28,280 ..he appears to even hold his breath. 187 00:34:49,040 --> 00:34:51,520 Success at last. 188 00:35:11,280 --> 00:35:15,520 All it took was a million years of evolution... 189 00:35:24,280 --> 00:35:29,040 ..and the unique stability of this ancient lake. 190 00:35:37,760 --> 00:35:41,680 Off the western coast of Equatorial Africa 191 00:35:41,680 --> 00:35:45,760 lies the volcanic island of Bioko. 192 00:35:45,760 --> 00:35:48,160 RUMBLE OF THUNDER 193 00:35:56,040 --> 00:36:00,360 Freshwater here has a turbulent nature. 194 00:36:36,040 --> 00:36:39,520 Few venture into such waters, 195 00:36:39,520 --> 00:36:44,040 but for those that do, there can be great rewards. 196 00:36:47,040 --> 00:36:50,200 After months feeding and growing out at sea, 197 00:36:50,200 --> 00:36:53,280 these gobies are ready to breed. 198 00:36:56,520 --> 00:36:59,680 And the safest place to lay their eggs 199 00:36:59,680 --> 00:37:03,520 is somewhere that ocean predators can't reach. 200 00:37:06,040 --> 00:37:08,520 The top of this waterfall. 201 00:37:14,280 --> 00:37:17,760 Surely an impossible journey for a fish. 202 00:37:21,760 --> 00:37:27,160 But over the coming days, the gobies transform themselves. 203 00:37:30,280 --> 00:37:32,120 They change colour. 204 00:37:37,040 --> 00:37:43,040 Their mouth rotates and acts like a kind of suction cup... 205 00:37:44,520 --> 00:37:47,040 ..which they will certainly need. 206 00:37:52,520 --> 00:37:56,560 Because the only way...is up. 207 00:38:17,760 --> 00:38:21,040 It is 30 metres to the top. 208 00:38:27,520 --> 00:38:31,080 They are only an inch long. 209 00:38:34,040 --> 00:38:38,520 This is the equivalent of a human being scaling a waterfall 210 00:38:38,520 --> 00:38:40,520 over a mile high. 211 00:38:50,040 --> 00:38:52,760 Millions attempt the climb... 212 00:38:54,040 --> 00:38:57,680 ..but less than 1% will make it. 213 00:39:07,280 --> 00:39:10,840 This goby has been climbing for days. 214 00:39:19,280 --> 00:39:21,000 Made it! 215 00:39:25,360 --> 00:39:29,760 Those that reach the top can now prepare to breed. 216 00:39:33,040 --> 00:39:38,280 And when the time comes, their young will be washed back out to sea. 217 00:39:59,280 --> 00:40:02,040 The extraordinary power of flowing water 218 00:40:02,040 --> 00:40:05,520 makes it our planet's greatest architect. 219 00:40:26,040 --> 00:40:30,520 This may look like the surface of an alien planet... 220 00:40:43,520 --> 00:40:49,200 ..but these strange patterns are channels of freshwater... 221 00:40:51,360 --> 00:40:53,760 .flowing towards the sea. 222 00:41:08,040 --> 00:41:11,040 For 3.8 billion years, 223 00:41:11,040 --> 00:41:13,920 ever since the first rains fell... 224 00:41:15,280 --> 00:41:18,680 ..freshwater has been making this journey. 225 00:41:34,280 --> 00:41:39,040 But today, two thirds of our world's great rivers 226 00:41:39,040 --> 00:41:41,680 no longer reach the sea. 227 00:41:53,880 --> 00:41:57,720 CREAKING 228 00:42:14,040 --> 00:42:18,280 There is a finite amount of freshwater on Earth... 229 00:42:30,520 --> 00:42:34,360 ..so humans have devised extraordinary means 230 00:42:34,360 --> 00:42:40,040 to ensure that it is always available to meet our every demand. 231 00:42:50,320 --> 00:42:53,520 We now control freshwater... 232 00:42:55,040 --> 00:42:57,280 ..on a colossal scale. 233 00:43:02,040 --> 00:43:05,040 The largest irrigation system on Earth 234 00:43:05,040 --> 00:43:08,440 has been built here in Pakistan. 235 00:43:09,960 --> 00:43:14,000 HORNS BLARE 236 00:43:17,520 --> 00:43:21,360 A vast network of dams and canals... 237 00:43:24,040 --> 00:43:28,520 ..that diverts and drains the great Indus River. 238 00:43:34,520 --> 00:43:39,280 It's used to irrigate an area the size of England. 239 00:43:44,040 --> 00:43:46,880 This man-made freshwater world 240 00:43:46,880 --> 00:43:49,760 provides water and a livelihood 241 00:43:49,760 --> 00:43:52,000 for millions of people... 242 00:43:52,000 --> 00:43:54,080 LAUGHTER 243 00:43:56,160 --> 00:43:59,960 CHATTER 244 00:43:59,960 --> 00:44:03,760 ..but at a cost to the natural world. 245 00:44:03,760 --> 00:44:07,360 CHATTER 246 00:44:16,520 --> 00:44:22,040 A rare creature has become stranded in this irrigation canal. 247 00:44:25,520 --> 00:44:28,480 And the water will soon be gone, 248 00:44:28,480 --> 00:44:32,040 used to supply the surrounding land. 249 00:44:38,280 --> 00:44:43,280 Endangered, they number fewer than 2,000 individuals. 250 00:44:48,760 --> 00:44:51,360 An Indus river dolphin. 251 00:44:52,920 --> 00:44:57,120 CHATTER, YELLING 252 00:45:05,280 --> 00:45:11,040 This female dolphin is 150 miles from the main river. 253 00:45:14,760 --> 00:45:17,400 She can't return on her own, 254 00:45:17,400 --> 00:45:22,520 so the only option is for this rescue team to take her. 255 00:45:22,520 --> 00:45:26,680 CHATTER 256 00:45:34,520 --> 00:45:37,600 CHATTER CONTINUES 257 00:45:46,520 --> 00:45:50,360 Out of water, she cannot survive for long. 258 00:45:50,360 --> 00:45:54,360 CHATTER 259 00:45:57,040 --> 00:46:00,440 The journey back to the river will take hours. 260 00:46:00,440 --> 00:46:05,160 CHATTER 261 00:46:10,040 --> 00:46:14,760 Her life now depends on these people. 262 00:46:36,040 --> 00:46:39,480 SIREN WAILS 263 00:47:33,160 --> 00:47:38,680 CHATTER 264 00:48:05,760 --> 00:48:11,560 Nearly 30 dolphins had to be rescued in one month alone. 265 00:48:41,760 --> 00:48:46,280 Freshwater is not only a resource for humans. 266 00:48:52,280 --> 00:48:57,040 It is the home for countless species 267 00:48:57,040 --> 00:49:02,200 that simply cannot survive without it. 268 00:49:21,040 --> 00:49:24,800 Freshwater is the lifeblood 269 00:49:24,800 --> 00:49:27,280 of Planet Earth. 270 00:49:49,040 --> 00:49:53,520 To film the story of the most endangered freshwater dolphin, 271 00:49:53,520 --> 00:49:58,280 the Planet Earth team joined the world's leading expert - Uzma Khan. 272 00:49:58,280 --> 00:50:02,520 The first time I saw Indus dolphin, I was just amazed. 273 00:50:02,520 --> 00:50:04,520 It's a beautiful creature, you know, 274 00:50:04,520 --> 00:50:07,240 it's like love at first sight. It's so unique. 275 00:50:08,760 --> 00:50:12,760 Uzma has been studying the last remaining population 276 00:50:12,760 --> 00:50:14,760 for over 20 years. 277 00:50:16,280 --> 00:50:19,960 There's a dolphin that surfaced just right there. 278 00:50:19,960 --> 00:50:24,560 Indus river dolphin can only live in freshwater. 279 00:50:24,560 --> 00:50:27,760 It is only found in Pakistan and nowhere else. 280 00:50:27,760 --> 00:50:32,040 And we only have about 2,000 of them left in the Indus River. 281 00:50:32,040 --> 00:50:36,240 So, you know, each individual is special. 282 00:50:38,320 --> 00:50:43,320 Following the dolphins in the murky water is extremely challenging. 283 00:50:44,320 --> 00:50:47,320 They only surface for a split second 284 00:50:47,320 --> 00:50:51,040 and that makes protecting them difficult, too. 285 00:50:51,040 --> 00:50:57,040 Their greatest threat is becoming trapped in the irrigation canals. 286 00:50:58,040 --> 00:51:00,800 But Uzma may have a solution, 287 00:51:00,800 --> 00:51:04,040 and teams up with a rescue unit... 288 00:51:05,040 --> 00:51:08,720 ..to attempt something never done before. 289 00:51:11,080 --> 00:51:14,040 This is the first time we'll be putting satellite tags 290 00:51:14,040 --> 00:51:16,040 on river dolphins in Asia. 291 00:51:16,040 --> 00:51:19,040 Sensors has not been tested on this species, 292 00:51:19,040 --> 00:51:22,360 there's a little bit of anxiety, but if they work, 293 00:51:22,360 --> 00:51:25,360 then it's going to be a breakthrough for conservation. 294 00:51:25,360 --> 00:51:28,400 SIREN WAILS 295 00:51:28,400 --> 00:51:33,400 Uzma has been developing a suitable tag for over ten years 296 00:51:33,400 --> 00:51:37,520 and hopes it will help her collect critical data 297 00:51:37,520 --> 00:51:41,040 on how the dolphins are moving through the dams and canals. 298 00:51:42,280 --> 00:51:47,280 But in order to tag, she will first need a successful rescue. 299 00:51:47,280 --> 00:51:51,400 CHATTER 300 00:51:57,040 --> 00:52:01,600 I'm usually very concerned when a rescue is happening. 301 00:52:11,520 --> 00:52:14,040 You know, the divers, they are very experienced, 302 00:52:14,040 --> 00:52:16,840 but a part of me is always very worried. 303 00:52:18,280 --> 00:52:21,520 They are wild animals that have never been handled. 304 00:52:23,440 --> 00:52:26,520 It's really quite a risky thing that they're undertaking here. 305 00:52:26,520 --> 00:52:28,760 There's a good chance the dolphin might die. 306 00:52:28,760 --> 00:52:31,520 But, of course, they're balancing that against the fact 307 00:52:31,520 --> 00:52:34,040 that they definitely will die if they stay in here, 308 00:52:34,040 --> 00:52:36,040 so it's a risk they have to take. 309 00:52:41,520 --> 00:52:45,520 CHATTER 310 00:52:52,280 --> 00:52:55,200 Have they got the dolphin? Yeah, I think so. They've got it. 311 00:52:58,520 --> 00:53:01,280 Now speed is key. 312 00:53:03,760 --> 00:53:07,480 CHATTER 313 00:53:10,520 --> 00:53:14,000 We're now bombing across the field on the way to the release site, 314 00:53:14,000 --> 00:53:16,520 and I think Uzma went ahead of us, so I'm really hopeful 315 00:53:16,520 --> 00:53:19,040 that she'll get her opportunity to tag the dolphin. 316 00:53:19,040 --> 00:53:22,760 SIREN WAILS 317 00:53:22,760 --> 00:53:27,040 But rescue missions don't always go to plan. 318 00:53:28,040 --> 00:53:29,840 LOUD RELEASE OF AIR 319 00:53:37,360 --> 00:53:39,040 A puncture. 320 00:53:46,520 --> 00:53:50,520 The dolphin is quickly moved to the film crew's truck. 321 00:53:59,680 --> 00:54:01,720 ANXIOUS CHATTER 322 00:54:11,400 --> 00:54:14,040 But with no roof for shelter, 323 00:54:14,040 --> 00:54:17,760 the dolphin is at greater risk of dehydration. 324 00:54:17,760 --> 00:54:20,360 The stakes are high, even right now. 325 00:54:21,360 --> 00:54:24,040 It's a cute little animal and we don't want it to die. 326 00:54:29,440 --> 00:54:33,120 The team re-route to the closest release site. 327 00:54:35,280 --> 00:54:37,360 There can be no more delay. 328 00:54:38,520 --> 00:54:41,000 Uzma calls off the tagging. 329 00:54:59,520 --> 00:55:02,200 It's unfortunate because we were all prepared, 330 00:55:02,200 --> 00:55:05,280 we were very excited since morning, all geared up, 331 00:55:05,280 --> 00:55:10,040 but hopefully we'll get an opportunity to tag the next rescue. 332 00:55:20,760 --> 00:55:25,280 A few days later, Uzma finally gets her chance. 333 00:55:31,320 --> 00:55:34,360 It's a very exciting day for us. 334 00:55:34,360 --> 00:55:36,280 It's OK. 335 00:55:36,280 --> 00:55:40,240 The moment that we have been waiting for, over ten years. 336 00:55:41,240 --> 00:55:43,120 Just stay calm. 337 00:55:48,240 --> 00:55:50,280 OK, it's good to go. 338 00:55:54,120 --> 00:55:56,360 Congratulations. 339 00:55:56,360 --> 00:55:58,440 Well done. 340 00:56:02,760 --> 00:56:06,320 I am very happy, very happy. 341 00:56:06,320 --> 00:56:08,880 I think it's a great accomplishment. 342 00:56:11,040 --> 00:56:13,760 It's the happiest moment of my life. 343 00:56:15,440 --> 00:56:18,320 APPLAUSE 344 00:56:20,520 --> 00:56:26,280 Within a few weeks, the tags begin to reveal some new insights. 345 00:56:28,280 --> 00:56:32,120 They are moving quite a lot, which we never expected. 346 00:56:32,120 --> 00:56:37,280 So one of the dolphins actually went about 46km upstream 347 00:56:37,280 --> 00:56:40,840 from the release site, and the other thing is that we thought 348 00:56:40,840 --> 00:56:43,280 that they will stay in the main river stream, 349 00:56:43,280 --> 00:56:47,280 but they are using side channels. It is extremely interesting. 350 00:56:48,280 --> 00:56:51,240 Tracking the movement of the tagged dolphins 351 00:56:51,240 --> 00:56:53,520 will help Uzma better understand 352 00:56:53,520 --> 00:56:56,520 when and where they become trapped... 353 00:56:57,760 --> 00:57:02,760 ..helping safeguard the future of this most endangered animal. 354 00:57:08,760 --> 00:57:10,520 Next time... 355 00:57:11,640 --> 00:57:13,240 ..forests. 356 00:57:14,840 --> 00:57:17,080 A hidden world... 357 00:57:17,080 --> 00:57:19,000 CHIRPING 358 00:57:19,000 --> 00:57:22,520 ..where lives are intimately entwined... 359 00:57:24,360 --> 00:57:27,360 ..in the most unexpected ways. 360 00:57:33,040 --> 00:57:37,240 Habitat Explorer brings animals and their habitats to life. 361 00:57:37,240 --> 00:57:40,880 Explore this free interactive and make origami animals. 362 00:57:40,880 --> 00:57:44,680 Go to bbc.co.uk/planetearth3 363 00:57:44,680 --> 00:57:47,120 and follow the links to the Open University. 364 00:57:47,120 --> 00:57:49,520 Or to order a free printed version, 365 00:57:49,520 --> 00:57:52,760 visit the website or call the number on the screen.