1 00:00:50,325 --> 00:00:54,765 Beneath the Yucatan Peninsula of Mexico... 2 00:00:56,285 --> 00:00:58,765 ...lies another world. 3 00:01:02,525 --> 00:01:05,045 A labyrinth of caves... 4 00:01:08,045 --> 00:01:11,765 ...carved by freshwater... 5 00:01:18,045 --> 00:01:21,645 ...and essential for life on Earth. 6 00:01:48,045 --> 00:01:53,845 Freshwater shapes the land and the creatures that live in it... 7 00:01:56,045 --> 00:01:58,685 ...in the most surprising ways. 8 00:02:14,525 --> 00:02:17,685 The rainforest of Costa Rica. 9 00:02:19,045 --> 00:02:23,525 As you might expect, it rains most days. 10 00:02:25,525 --> 00:02:28,765 But it's only during the wet season 11 00:02:28,765 --> 00:02:32,045 that the rains become torrential. 12 00:02:40,525 --> 00:02:42,245 And with them... 13 00:02:43,245 --> 00:02:46,285 ...comes a most remarkable creature. 14 00:03:01,285 --> 00:03:04,485 Gliding tree frogs. 15 00:03:09,885 --> 00:03:12,685 Thousands drop in... 16 00:03:16,045 --> 00:03:20,045 ...to gather at this newly-formed pond. 17 00:03:27,285 --> 00:03:30,445 They all have an urgent need. 18 00:03:36,365 --> 00:03:38,045 To breed. 19 00:03:51,285 --> 00:03:54,765 This female needs to find a leaf 20 00:03:54,765 --> 00:03:56,965 and lay her eggs. 21 00:04:02,045 --> 00:04:06,045 The breeding frenzy will only last one day... 22 00:04:07,045 --> 00:04:10,045 ...so she needs to get a move on. 23 00:04:15,525 --> 00:04:18,285 There are lots of eager males. 24 00:04:24,405 --> 00:04:26,685 Nine for every female. 25 00:04:30,525 --> 00:04:35,205 And all are ready to spring into action. 26 00:04:40,765 --> 00:04:45,045 So, for her, getting a partner is no problem. 27 00:04:54,645 --> 00:04:57,765 But the other males are desperate. 28 00:05:18,325 --> 00:05:22,765 For this female, mating is rather chaotic. 29 00:05:34,085 --> 00:05:36,765 Things are getting out of hand. 30 00:05:45,005 --> 00:05:48,445 There is one way to deal with this. 31 00:05:54,525 --> 00:05:57,085 A few well-placed kicks... 32 00:06:00,045 --> 00:06:02,045 ...usually does the job. 33 00:06:14,525 --> 00:06:16,285 Problem solved. 34 00:06:20,525 --> 00:06:24,525 She and her partner can now finally mate... 35 00:06:26,045 --> 00:06:28,045 ...in relative peace. 36 00:06:58,525 --> 00:07:02,045 The eggs are positioned perfectly... 37 00:07:02,045 --> 00:07:05,045 ...directly overhanging the pond. 38 00:07:23,485 --> 00:07:28,285 This is the ideal nursery for tadpoles. 39 00:07:31,765 --> 00:07:34,765 For now, her work here is done. 40 00:07:35,765 --> 00:07:40,045 She'll be back next year when the heavy rains return. 41 00:07:44,045 --> 00:07:47,045 As quickly as freshwater appears... 42 00:07:49,525 --> 00:07:51,365 ...it can vanish. 43 00:08:03,525 --> 00:08:05,805 Southeast Sri Lanka. 44 00:08:08,845 --> 00:08:11,525 It's the middle of the dry season. 45 00:08:28,045 --> 00:08:33,045 This is the only remaining water hole for miles around. 46 00:09:31,725 --> 00:09:34,045 Mugger crocodiles - 47 00:09:34,045 --> 00:09:37,525 giants, five metres long. 48 00:09:40,445 --> 00:09:42,765 Dozens are hiding... 49 00:09:43,765 --> 00:09:46,045 ...beneath the surface. 50 00:09:54,045 --> 00:09:55,845 And others... 51 00:09:56,845 --> 00:09:58,765 ...are on their way. 52 00:10:16,765 --> 00:10:20,045 This male has been travelling for hours. 53 00:10:26,765 --> 00:10:30,365 The water hole is the only place where he has a chance 54 00:10:30,365 --> 00:10:32,125 to catch a deer. 55 00:10:43,685 --> 00:10:49,045 A single adult would be enough to feed him for the entire dry season. 56 00:11:00,045 --> 00:11:03,125 {\an8}But hunting prey that knows you're here... 57 00:11:04,125 --> 00:11:07,285 ...requires something truly remarkable. 58 00:11:25,285 --> 00:11:27,045 He creates... 59 00:11:28,045 --> 00:11:29,765 ...a trap. 60 00:11:39,725 --> 00:11:42,765 He digs down into the mud... 61 00:11:56,045 --> 00:11:59,765 ...deep enough to hide beneath the vegetation. 62 00:12:17,045 --> 00:12:19,685 Perfect camouflage. 63 00:12:31,045 --> 00:12:35,045 He has built his trap right on the water's edge... 64 00:12:36,765 --> 00:12:41,365 ...so it's the first place that thirsty deer will come to drink. 65 00:14:37,045 --> 00:14:40,285 These crocodiles have learned to exploit 66 00:14:40,285 --> 00:14:43,525 the deer's desperate need for freshwater. 67 00:14:56,285 --> 00:15:00,525 Freshwater transforms not only the lives of animals... 68 00:15:02,285 --> 00:15:04,765 ...but entire landscapes. 69 00:15:17,285 --> 00:15:21,045 Every year, over a trillion litres of water 70 00:15:21,045 --> 00:15:24,045 flow into the Kalahari Desert. 71 00:15:32,365 --> 00:15:37,045 It has travelled a thousand miles from where it fell as rain. 72 00:15:42,285 --> 00:15:44,165 And on arrival... 73 00:15:46,045 --> 00:15:48,885 ...it turns the Kalahari... 74 00:15:48,885 --> 00:15:52,045 ...into a vast oasis. 75 00:16:01,045 --> 00:16:03,365 The Okavango Delta. 76 00:16:25,605 --> 00:16:29,525 These waters attract millions of animals. 77 00:16:38,285 --> 00:16:44,045 And for some, now is the perfect time to raise a family. 78 00:16:57,285 --> 00:16:59,125 {\an8}A lily-trotter. 79 00:17:05,525 --> 00:17:08,045 And he is a father... 80 00:17:08,045 --> 00:17:09,765 ...on duty. 81 00:17:28,765 --> 00:17:30,885 He has not just one... 82 00:17:32,645 --> 00:17:36,445 ...but four newly-hatched chicks. 83 00:17:52,045 --> 00:17:56,525 They won't be able to fly for another six weeks... 84 00:17:59,485 --> 00:18:04,045 ...so, until then, he alone is their protector. 85 00:18:10,525 --> 00:18:14,765 Walking on water is not straightforward... 86 00:18:17,525 --> 00:18:22,245 ...so he must show them how to be a lily-trotter. 87 00:18:43,525 --> 00:18:47,525 The floodwaters make the perfect training ground. 88 00:19:03,685 --> 00:19:06,045 And in two weeks... 89 00:19:07,285 --> 00:19:10,765 ...his chicks not only double in size... 90 00:19:11,765 --> 00:19:14,365 ...they grow in confidence. 91 00:19:26,045 --> 00:19:30,045 But this is a dangerous place to stray. 92 00:19:39,045 --> 00:19:41,485 He sounds the alarm, 93 00:19:41,485 --> 00:19:44,765 and his chicks instantly freeze. 94 00:19:46,765 --> 00:19:49,365 They can't yet fly to safety. 95 00:19:52,365 --> 00:19:55,765 But there is one thing he can do to protect them. 96 00:19:58,045 --> 00:20:00,285 And it's risky. 97 00:20:03,125 --> 00:20:06,285 Get close enough to distract... 98 00:20:07,525 --> 00:20:10,285 ...and hopefully divert the crocodile. 99 00:20:40,765 --> 00:20:42,765 Mission accomplished. 100 00:20:57,525 --> 00:21:00,045 He signals the all clear. 101 00:21:13,045 --> 00:21:15,525 But one chick is missing. 102 00:21:39,045 --> 00:21:41,525 His calls... 103 00:21:41,525 --> 00:21:43,525 ...go unanswered. 104 00:22:37,045 --> 00:22:40,685 A little bedraggled but alive and well. 105 00:22:46,885 --> 00:22:50,285 His chick just hadn't heard his call. 106 00:22:51,765 --> 00:22:53,925 And when danger threatens, 107 00:22:53,925 --> 00:22:57,285 its always better to be safe than sorry. 108 00:23:25,525 --> 00:23:28,565 {\an8}He's brought his chicks, all four of them, 109 00:23:28,565 --> 00:23:31,285 to the verge of independence. 110 00:23:45,045 --> 00:23:47,765 Whilst lily-trotters are well adapted 111 00:23:47,765 --> 00:23:50,205 to life in this flooded world... 112 00:23:53,245 --> 00:23:57,205 ...these residents of the delta are not. 113 00:24:08,525 --> 00:24:11,045 African painted dogs. 114 00:24:14,285 --> 00:24:18,045 Normally, they are remarkably successful hunters. 115 00:24:19,045 --> 00:24:23,365 But this pack of five hasn't eaten in days. 116 00:24:29,045 --> 00:24:32,365 Finding prey isn't the problem. 117 00:24:39,285 --> 00:24:43,765 This herd of lechwe is only a few hundred metres away. 118 00:24:48,525 --> 00:24:52,045 But between them is deep water. 119 00:25:27,805 --> 00:25:30,765 It's not safe to cross here. 120 00:27:16,525 --> 00:27:21,285 On dry land, the dogs can run at over 40mph. 121 00:27:27,525 --> 00:27:32,525 But when threatened, lechwe always seek the safety of water. 122 00:27:38,285 --> 00:27:41,645 With their splayed hooves and long hind legs, 123 00:27:41,645 --> 00:27:44,285 they can power their way through the water. 124 00:27:46,045 --> 00:27:48,405 The dogs can't. 125 00:28:12,045 --> 00:28:16,325 The pack won't be able to outswim the lechwe. 126 00:28:19,365 --> 00:28:21,765 But they do have a strategy. 127 00:28:42,765 --> 00:28:47,045 The dogs drive the lechwe to where they have the advantage. 128 00:28:52,765 --> 00:28:55,485 Back towards dry land. 129 00:28:59,285 --> 00:29:03,045 Now the pack can regain lost ground. 130 00:29:50,645 --> 00:29:56,045 Success today, but tomorrow the pack will need to hunt again. 131 00:29:59,765 --> 00:30:01,485 In the Okavango, 132 00:30:01,485 --> 00:30:07,045 animals must always adapt to the coming and going of freshwater. 133 00:30:11,765 --> 00:30:16,765 But there are a few rare places, as here in Lake Malawi, 134 00:30:16,765 --> 00:30:20,765 where freshwater has lain for millions of years. 135 00:30:23,365 --> 00:30:26,525 And that has enabled life to evolve 136 00:30:26,525 --> 00:30:30,765 into a dazzling diversity of species. 137 00:30:37,445 --> 00:30:41,045 There are over a thousand different kinds of fish here... 138 00:30:42,285 --> 00:30:45,045 ...more than any other lake on Earth. 139 00:30:56,045 --> 00:31:00,285 Competition in these waters is intense. 140 00:31:22,925 --> 00:31:27,285 Meet Nimbochromis livingstonii. 141 00:31:30,525 --> 00:31:32,805 A master of deception 142 00:31:32,805 --> 00:31:37,045 that tricks other fish into thinking it's dead. 143 00:31:41,045 --> 00:31:45,525 Its mottled colouration mimics decaying flesh. 144 00:31:51,525 --> 00:31:53,925 But to appear dead... 145 00:31:57,045 --> 00:31:58,925 ...one must at least... 146 00:31:59,925 --> 00:32:01,965 ...act dead. 147 00:32:05,525 --> 00:32:08,685 This juvenile is fooling no-one. 148 00:32:13,845 --> 00:32:18,045 Perhaps faking his death will be more believable. 149 00:32:44,045 --> 00:32:45,685 Blown it. 150 00:32:56,045 --> 00:32:59,045 A more subtle performance will be needed. 151 00:33:12,285 --> 00:33:14,885 This is more convincing. 152 00:33:27,405 --> 00:33:30,285 But his aim must be better than that. 153 00:33:37,685 --> 00:33:39,205 Nearly. 154 00:33:46,765 --> 00:33:49,605 It seems he's overstayed his welcome. 155 00:34:22,685 --> 00:34:24,885 {\an8}In a final effort... 156 00:34:24,885 --> 00:34:28,285 {\an8}...he appears to even hold his breath. 157 00:34:49,045 --> 00:34:51,525 Success at last. 158 00:35:11,285 --> 00:35:15,525 All it took was a million years of evolution... 159 00:35:24,285 --> 00:35:29,045 ...and the unique stability of this ancient lake. 160 00:35:37,765 --> 00:35:41,685 Off the western coast of Equatorial Africa 161 00:35:41,685 --> 00:35:45,765 lies the volcanic island of Bioko. 162 00:35:56,045 --> 00:36:00,365 Freshwater here has a turbulent nature. 163 00:36:36,045 --> 00:36:39,525 Few venture into such waters, 164 00:36:39,525 --> 00:36:44,045 but for those that do, there can be great rewards. 165 00:36:47,045 --> 00:36:50,205 After months feeding and growing out at sea, 166 00:36:50,205 --> 00:36:53,285 these gobies are ready to breed. 167 00:36:56,525 --> 00:36:59,685 And the safest place to lay their eggs 168 00:36:59,685 --> 00:37:03,525 is somewhere that ocean predators can't reach. 169 00:37:06,045 --> 00:37:08,525 The top of this waterfall. 170 00:37:14,285 --> 00:37:17,765 Surely an impossible journey for a fish. 171 00:37:21,765 --> 00:37:27,165 But over the coming days, the gobies transform themselves. 172 00:37:30,285 --> 00:37:32,125 They change colour. 173 00:37:37,045 --> 00:37:43,045 Their mouth rotates and acts like a kind of suction cup... 174 00:37:44,525 --> 00:37:47,045 ...which they will certainly need. 175 00:37:52,525 --> 00:37:56,565 Because the only way... is up. 176 00:38:17,765 --> 00:38:21,045 It is 30 metres to the top. 177 00:38:27,525 --> 00:38:31,085 They are only an inch long. 178 00:38:34,045 --> 00:38:38,525 This is the equivalent of a human being scaling a waterfall 179 00:38:38,525 --> 00:38:40,525 over a mile high. 180 00:38:50,045 --> 00:38:52,765 Millions attempt the climb... 181 00:38:54,045 --> 00:38:57,685 ...but less than 1% will make it. 182 00:39:07,285 --> 00:39:10,845 This goby has been climbing for days. 183 00:39:19,285 --> 00:39:21,005 Made it! 184 00:39:25,365 --> 00:39:29,765 Those that reach the top can now prepare to breed. 185 00:39:33,045 --> 00:39:38,285 And when the time comes, their young will be washed back out to sea. 186 00:39:59,285 --> 00:40:02,045 The extraordinary power of flowing water 187 00:40:02,045 --> 00:40:05,525 makes it our planet's greatest architect. 188 00:40:26,045 --> 00:40:30,525 This may look like the surface of an alien planet... 189 00:40:43,525 --> 00:40:49,205 ...but these strange patterns are channels of freshwater... 190 00:40:51,365 --> 00:40:53,765 ...flowing towards the sea. 191 00:41:08,045 --> 00:41:11,045 For 3.8 billion years, 192 00:41:11,045 --> 00:41:13,925 ever since the first rains fell... 193 00:41:15,285 --> 00:41:18,685 ...freshwater has been making this journey. 194 00:41:34,285 --> 00:41:39,045 But today, two thirds of our world's great rivers 195 00:41:39,045 --> 00:41:41,685 no longer reach the sea. 196 00:42:14,045 --> 00:42:18,285 There is a finite amount of freshwater on Earth... 197 00:42:30,525 --> 00:42:34,365 ...so humans have devised extraordinary means 198 00:42:34,365 --> 00:42:40,045 to ensure that it is always available to meet our every demand. 199 00:42:50,325 --> 00:42:53,525 We now control freshwater... 200 00:42:55,045 --> 00:42:57,285 ...on a colossal scale. 201 00:43:02,045 --> 00:43:05,045 The largest irrigation system on Earth 202 00:43:05,045 --> 00:43:08,445 has been built here in Pakistan. 203 00:43:17,525 --> 00:43:21,365 A vast network of dams and canals... 204 00:43:24,045 --> 00:43:28,525 ...that diverts and drains the great Indus River. 205 00:43:34,525 --> 00:43:39,285 It's used to irrigate an area the size of England. 206 00:43:44,045 --> 00:43:46,885 This man-made freshwater world 207 00:43:46,885 --> 00:43:49,765 provides water and a livelihood 208 00:43:49,765 --> 00:43:52,005 for millions of people... 209 00:43:59,965 --> 00:44:03,765 ...but at a cost to the natural world. 210 00:44:16,525 --> 00:44:22,045 A rare creature has become stranded in this irrigation canal. 211 00:44:25,525 --> 00:44:28,485 And the water will soon be gone, 212 00:44:28,485 --> 00:44:32,045 used to supply the surrounding land. 213 00:44:38,285 --> 00:44:43,285 Endangered, they number fewer than 2,000 individuals. 214 00:44:48,765 --> 00:44:51,365 An Indus river dolphin. 215 00:45:05,285 --> 00:45:11,045 This female dolphin is 150 miles from the main river. 216 00:45:14,765 --> 00:45:17,405 She can't return on her own, 217 00:45:17,405 --> 00:45:22,525 so the only option is for this rescue team to take her. 218 00:45:46,525 --> 00:45:50,365 Out of water, she cannot survive for long. 219 00:45:57,045 --> 00:46:00,445 The journey back to the river will take hours. 220 00:46:10,045 --> 00:46:14,765 Her life now depends on these people. 221 00:48:05,765 --> 00:48:11,565 Nearly 30 dolphins had to be rescued in one month alone. 222 00:48:41,765 --> 00:48:46,285 Freshwater is not only a resource for humans. 223 00:48:52,285 --> 00:48:57,045 It is the home for countless species 224 00:48:57,045 --> 00:49:02,205 that simply cannot survive without it. 225 00:49:21,045 --> 00:49:24,805 Freshwater is the lifeblood 226 00:49:24,805 --> 00:49:27,285 of Planet Earth. 227 00:49:49,045 --> 00:49:53,525 To film the story of the most endangered freshwater dolphin, 228 00:49:53,525 --> 00:49:58,285 the Planet Earth team joined the world's leading expert - Uzma Khan. 229 00:49:58,285 --> 00:50:02,525 The first time I saw Indus dolphin, I was just amazed. 230 00:50:02,525 --> 00:50:04,525 It's a beautiful creature, you know, 231 00:50:04,525 --> 00:50:07,245 it's like love at first sight. It's so unique. 232 00:50:08,765 --> 00:50:12,765 Uzma has been studying the last remaining population 233 00:50:12,765 --> 00:50:14,765 for over 20 years. 234 00:50:16,285 --> 00:50:19,965 There's a dolphin that surfaced just right there. 235 00:50:19,965 --> 00:50:24,565 Indus river dolphin can only live in freshwater. 236 00:50:24,565 --> 00:50:27,765 It is only found in Pakistan and nowhere else. 237 00:50:27,765 --> 00:50:32,045 And we only have about 2,000 of them left in the Indus River. 238 00:50:32,045 --> 00:50:36,245 So, you know, each individual is special. 239 00:50:38,325 --> 00:50:43,325 Following the dolphins in the murky water is extremely challenging. 240 00:50:44,325 --> 00:50:47,325 They only surface for a split second 241 00:50:47,325 --> 00:50:51,045 and that makes protecting them difficult, too. 242 00:50:51,045 --> 00:50:57,045 Their greatest threat is becoming trapped in the irrigation canals. 243 00:50:58,045 --> 00:51:00,805 But Uzma may have a solution, 244 00:51:00,805 --> 00:51:04,045 and teams up with a rescue unit... 245 00:51:05,045 --> 00:51:08,725 ...to attempt something never done before. 246 00:51:11,085 --> 00:51:14,045 This is the first time we'll be putting satellite tags 247 00:51:14,045 --> 00:51:16,045 on river dolphins in Asia. 248 00:51:16,045 --> 00:51:19,045 Sensors has not been tested on this species, 249 00:51:19,045 --> 00:51:22,365 there's a little bit of anxiety, but if they work, 250 00:51:22,365 --> 00:51:25,365 then it's going to be a breakthrough for conservation. 251 00:51:28,405 --> 00:51:33,405 Uzma has been developing a suitable tag for over ten years 252 00:51:33,405 --> 00:51:37,525 and hopes it will help her collect critical data 253 00:51:37,525 --> 00:51:41,045 on how the dolphins are moving through the dams and canals. 254 00:51:42,285 --> 00:51:47,285 But in order to tag, she will first need a successful rescue. 255 00:51:57,045 --> 00:52:01,605 I'm usually very concerned when a rescue is happening. 256 00:52:11,525 --> 00:52:14,045 You know, the divers, they are very experienced, 257 00:52:14,045 --> 00:52:16,845 but a part of me is always very worried. 258 00:52:18,285 --> 00:52:21,525 They are wild animals that have never been handled. 259 00:52:23,445 --> 00:52:26,525 It's really quite a risky thing that they're undertaking here. 260 00:52:26,525 --> 00:52:28,765 There's a good chance the dolphin might die. 261 00:52:28,765 --> 00:52:31,525 But, of course, they're balancing that against the fact 262 00:52:31,525 --> 00:52:34,045 that they definitely will die if they stay in here, 263 00:52:34,045 --> 00:52:36,045 so it's a risk they have to take. 264 00:52:52,285 --> 00:52:55,205 Have they got the dolphin? Yeah, I think so. They've got it. 265 00:52:58,525 --> 00:53:01,285 Now speed is key. 266 00:53:10,525 --> 00:53:14,005 We're now bombing across the field on the way to the release site, 267 00:53:14,005 --> 00:53:16,525 and I think Uzma went ahead of us, so I'm really hopeful 268 00:53:16,525 --> 00:53:19,045 that she'll get her opportunity to tag the dolphin. 269 00:53:22,765 --> 00:53:27,045 But rescue missions don't always go to plan. 270 00:53:37,365 --> 00:53:39,045 A puncture. 271 00:53:46,525 --> 00:53:50,525 The dolphin is quickly moved to the film crew's truck. 272 00:54:11,405 --> 00:54:14,045 But with no roof for shelter, 273 00:54:14,045 --> 00:54:17,765 the dolphin is at greater risk of dehydration. 274 00:54:17,765 --> 00:54:20,365 The stakes are high, even right now. 275 00:54:21,365 --> 00:54:24,045 It's a cute little animal and we don't want it to die. 276 00:54:29,445 --> 00:54:33,125 The team re-route to the closest release site. 277 00:54:35,285 --> 00:54:37,365 There can be no more delay. 278 00:54:38,525 --> 00:54:41,005 Uzma calls off the tagging. 279 00:54:59,525 --> 00:55:02,205 It's unfortunate because we were all prepared, 280 00:55:02,205 --> 00:55:05,285 we were very excited since morning, all geared up, 281 00:55:05,285 --> 00:55:10,045 but hopefully we'll get an opportunity to tag the next rescue. 282 00:55:20,765 --> 00:55:25,285 A few days later, Uzma finally gets her chance. 283 00:55:31,325 --> 00:55:34,365 It's a very exciting day for us. 284 00:55:34,365 --> 00:55:36,285 It's OK. 285 00:55:36,285 --> 00:55:40,245 The moment that we have been waiting for, over ten years. 286 00:55:41,245 --> 00:55:43,125 Just stay calm. 287 00:55:48,245 --> 00:55:50,285 OK, it's good to go. 288 00:55:54,125 --> 00:55:56,365 Congratulations. 289 00:55:56,365 --> 00:55:58,445 Well done. 290 00:56:02,765 --> 00:56:06,325 I am very happy, very happy. 291 00:56:06,325 --> 00:56:08,885 I think it's a great accomplishment. 292 00:56:11,045 --> 00:56:13,765 It's the happiest moment of my life. 293 00:56:20,525 --> 00:56:26,285 Within a few weeks, the tags begin to reveal some new insights. 294 00:56:28,285 --> 00:56:32,125 They are moving quite a lot, which we never expected. 295 00:56:32,125 --> 00:56:37,285 So one of the dolphins actually went about 46km upstream 296 00:56:37,285 --> 00:56:40,845 from the release site, and the other thing is that we thought 297 00:56:40,845 --> 00:56:43,285 that they will stay in the main river stream, 298 00:56:43,285 --> 00:56:47,285 but they are using side channels. It is extremely interesting. 299 00:56:48,285 --> 00:56:51,245 Tracking the movement of the tagged dolphins 300 00:56:51,245 --> 00:56:53,525 will help Uzma better understand 301 00:56:53,525 --> 00:56:56,525 when and where they become trapped... 302 00:56:57,765 --> 00:57:02,765 ...helping safeguard the future of this most endangered animal. 303 00:57:08,765 --> 00:57:10,525 Next time... 304 00:57:11,645 --> 00:57:13,245 ...forests. 305 00:57:14,845 --> 00:57:17,085 A hidden world... 306 00:57:19,005 --> 00:57:22,525 ...where lives are intimately entwined... 307 00:57:24,365 --> 00:57:27,365 ...in the most unexpected ways. 308 00:57:33,045 --> 00:57:37,245 Habitat Explorer brings animals and their habitats to life. 309 00:57:37,245 --> 00:57:40,885 Explore this free interactive and make origami animals. 310 00:57:40,885 --> 00:57:44,685 Go to bbc.co.uk/planetearth3 311 00:57:44,685 --> 00:57:47,125 and follow the links to the Open University. 312 00:57:47,125 --> 00:57:49,525 Or to order a free printed version, 313 00:57:49,525 --> 00:57:52,765 visit the website or call the number on the screen.