1 00:00:02,200 --> 00:00:05,260 The sun rises on Japan. 2 00:00:06,900 --> 00:00:09,940 More than 6,000 islands on the edge of the Pacific. 3 00:00:15,940 --> 00:00:20,740 Life here is at the mercy of Earth's most powerful elemental forces. 4 00:00:27,620 --> 00:00:30,060 From the wilds of the frozen north... 5 00:00:31,940 --> 00:00:33,540 BIRDS SQUAWK 6 00:00:33,540 --> 00:00:36,380 ..to the subtropical warmth of the south. 7 00:00:38,940 --> 00:00:42,020 Animals along this chain of islands have had to adapt 8 00:00:42,020 --> 00:00:44,620 in unique and sometimes bizarre ways. 9 00:00:51,860 --> 00:00:53,220 Throughout this land, 10 00:00:53,220 --> 00:00:56,260 people have developed an extraordinary relationship 11 00:00:56,260 --> 00:00:57,980 with the natural world. 12 00:00:57,980 --> 00:01:00,780 BEAR GROWLS 13 00:01:06,820 --> 00:01:09,260 Trying to capture its fleeting beauty... 14 00:01:13,140 --> 00:01:14,940 ..and tame its spirit. 15 00:01:16,380 --> 00:01:20,220 But these islands remain wild, mysterious and magical. 16 00:01:22,820 --> 00:01:25,580 This is Japan. 17 00:01:25,580 --> 00:01:27,900 BIRDS SQUAWK 18 00:01:32,540 --> 00:01:36,300 In Japan's far south, there's a chain of tiny islands 19 00:01:36,300 --> 00:01:39,740 stretching for 750 miles towards the tropics. 20 00:01:42,380 --> 00:01:46,100 Isolated in the vast Pacific Ocean, 21 00:01:46,100 --> 00:01:48,500 these islands are ruled by the sea. 22 00:01:57,460 --> 00:02:00,260 Here, you have to live life with a different spirit. 23 00:02:02,900 --> 00:02:05,740 And the further south you go... 24 00:02:05,740 --> 00:02:07,460 the stranger life seems to become. 25 00:02:10,820 --> 00:02:12,820 SHE SPEAKS JAPANESE 26 00:02:25,860 --> 00:02:29,140 At the top of the chain lies the island of Yakushima. 27 00:02:36,420 --> 00:02:39,860 A narrow channel is all that separates it from the mainland. 28 00:02:42,700 --> 00:02:44,540 It's like a lost world. 29 00:02:53,660 --> 00:02:57,100 Its steep slopes are mostly covered in forest 30 00:02:57,100 --> 00:03:00,420 and some of the trees are thousands of years old. 31 00:03:11,340 --> 00:03:13,780 A family of Japanese macaques. 32 00:03:15,260 --> 00:03:17,820 They share this island with another animal... 33 00:03:19,340 --> 00:03:20,580 ..sika deer. 34 00:03:31,260 --> 00:03:33,580 Deer and macaques live all over Japan... 35 00:03:35,820 --> 00:03:40,260 ..but here on Yakushima, the two species live side-by-side. 36 00:03:44,060 --> 00:03:48,140 And the rowdier young monkeys do something very unusual. 37 00:03:55,820 --> 00:03:57,980 They ride on the deers' backs. 38 00:04:01,100 --> 00:04:02,860 MACAQUE SQUEAKS 39 00:04:12,900 --> 00:04:17,620 Why they do it, and why the deer put up with it, is not entirely clear... 40 00:04:21,180 --> 00:04:23,460 ..but it only happens here on Yakushima. 41 00:04:30,580 --> 00:04:33,380 There comes a point when the deer have had enough. 42 00:04:35,660 --> 00:04:36,860 MACAQUE SQUEAKS 43 00:04:43,140 --> 00:04:45,780 But there are advantages to hanging out with monkeys. 44 00:04:55,180 --> 00:04:58,220 Every day, the macaques forage up in the trees. 45 00:04:59,500 --> 00:05:05,100 The deer listen for their feeding calls and follow them around, 46 00:05:05,100 --> 00:05:06,540 picking up what they drop. 47 00:05:07,940 --> 00:05:10,700 It's food they could never reach themselves. 48 00:05:21,420 --> 00:05:23,380 It's an easy-going relationship. 49 00:05:24,780 --> 00:05:28,580 But even the best of friends can fall out over something trivial, 50 00:05:28,580 --> 00:05:30,060 like a stolen leaf. 51 00:05:30,060 --> 00:05:31,620 MACAQUE SQUEALS 52 00:05:36,980 --> 00:05:38,260 MACAQUE SQUEALS 53 00:05:43,980 --> 00:05:48,060 No-one really knows why these two animals have such a close bond... 54 00:05:50,860 --> 00:05:52,820 ..but strange things can happen 55 00:05:52,820 --> 00:05:55,260 when you are cast away on isolated islands. 56 00:06:03,940 --> 00:06:07,180 Enormous volcanic forces created Yakushima 57 00:06:07,180 --> 00:06:08,940 and many of the islands beyond it. 58 00:06:18,020 --> 00:06:21,860 The sea level rose and Yakushima was cut off from the rest of Japan. 59 00:06:29,020 --> 00:06:31,220 The deer and the macaques were marooned together 60 00:06:31,220 --> 00:06:32,940 in this odd little world, 61 00:06:32,940 --> 00:06:35,260 where life could follow different rules. 62 00:06:47,260 --> 00:06:51,020 This part of Japan lies along a great rift in the Earth's crust. 63 00:06:52,660 --> 00:06:56,580 It's one of the most geologically unstable places in the world. 64 00:07:01,500 --> 00:07:04,140 It has 18 active volcanoes. 65 00:07:10,460 --> 00:07:11,860 VOLCANO RUMBLES 66 00:07:19,500 --> 00:07:21,580 Some of the largest in the world. 67 00:07:29,900 --> 00:07:30,780 VOLCANO RUMBLES 68 00:07:41,100 --> 00:07:44,780 Sakurajima is Japan's most active volcano. 69 00:07:44,780 --> 00:07:45,740 VOLCANO RUMBLES 70 00:07:47,740 --> 00:07:51,700 It has been erupting nonstop for the last 60 years. 71 00:08:00,220 --> 00:08:04,700 Even so, over half a million people live next to this smoking giant, 72 00:08:04,700 --> 00:08:07,900 never quite sure when it might get really violent. 73 00:08:07,900 --> 00:08:08,860 BIRD CAWS 74 00:08:13,580 --> 00:08:15,660 VOLCANO RUMBLES 75 00:08:21,100 --> 00:08:25,380 Every few weeks, it belches out thousands of tonnes of ash, 76 00:08:25,380 --> 00:08:26,380 covering the city. 77 00:08:44,460 --> 00:08:46,980 It might not seem like the ideal place to live... 78 00:08:48,940 --> 00:08:53,020 ..but with a few simple precautions, life can be almost normal. 79 00:09:00,340 --> 00:09:03,580 Rocks the size of tennis balls can rain down at any time. 80 00:09:05,180 --> 00:09:07,460 It gives the school run an element of peril... 81 00:09:09,060 --> 00:09:11,060 ..but these children are used to it. 82 00:09:26,700 --> 00:09:28,380 JAPANESE SPOKEN OVER TANNOY 83 00:09:35,500 --> 00:09:37,340 The school day always begins 84 00:09:37,340 --> 00:09:39,900 with a sweep-up of last night's shower of ash. 85 00:09:45,060 --> 00:09:49,460 Despite the risks, people have been living in the shadow of Sakurajima 86 00:09:49,460 --> 00:09:51,300 for thousands of years... 87 00:09:51,300 --> 00:09:52,900 but there are advantages. 88 00:09:56,140 --> 00:10:00,580 The volcanic soil is fertile and farms crowd the lower slopes... 89 00:10:02,220 --> 00:10:05,020 ..but the volcanic warmth brings unexpected benefits. 90 00:10:08,060 --> 00:10:10,980 On this local beach, nobody goes swimming. 91 00:10:12,260 --> 00:10:14,060 The water could kill you. 92 00:10:17,180 --> 00:10:18,700 It's hot enough to brew tea. 93 00:10:24,620 --> 00:10:28,260 There's not much life in the sea around here, 94 00:10:28,260 --> 00:10:31,620 but the resourceful people of this island have found a way 95 00:10:31,620 --> 00:10:32,940 to create a paradise. 96 00:10:42,500 --> 00:10:44,500 A steaming sand bath. 97 00:10:53,660 --> 00:10:55,780 People travel from all over Japan 98 00:10:55,780 --> 00:10:58,180 to be buried up to their necks in hot sand. 99 00:10:59,940 --> 00:11:02,180 They've been doing it for hundreds of years. 100 00:11:08,980 --> 00:11:13,180 They say it improves circulation, and restores health and vitality. 101 00:11:18,740 --> 00:11:21,260 If nothing else, it's a nice lie down. 102 00:11:32,660 --> 00:11:34,780 When you live next to a volcano, 103 00:11:34,780 --> 00:11:37,340 you might have to deal with its dangers, 104 00:11:37,340 --> 00:11:39,660 but you can still relish its delights. 105 00:11:45,060 --> 00:11:47,700 Heading south along Japan's island chain, 106 00:11:47,700 --> 00:11:50,940 life becomes more and more influenced by the sea. 107 00:11:56,220 --> 00:11:58,260 It brings something to these islands 108 00:11:58,260 --> 00:12:00,500 that affects everything that lives here. 109 00:12:07,820 --> 00:12:09,740 The Kuroshio Current - 110 00:12:09,740 --> 00:12:13,300 one of the most powerful ocean currents in the world. 111 00:12:14,660 --> 00:12:16,340 Japan's own Gulf Stream. 112 00:12:18,860 --> 00:12:20,780 It surges up from the equator 113 00:12:20,780 --> 00:12:23,940 and delivers 50 million tonnes of warm water every second... 114 00:12:28,540 --> 00:12:30,940 ..and brings a touch of tropical magic... 115 00:12:44,060 --> 00:12:47,420 ..creating the perfect conditions for coral reefs. 116 00:12:58,780 --> 00:13:01,460 It's only the warmth of the Kuroshio Current 117 00:13:01,460 --> 00:13:05,180 that allows coral to grow this far north in the Pacific Ocean. 118 00:13:16,380 --> 00:13:19,140 The current also brings nutrients from the deep. 119 00:13:36,860 --> 00:13:41,980 There's one very small resident who never strays far from the reef. 120 00:13:41,980 --> 00:13:45,100 He's a bluestreak cleaner wrasse... 121 00:13:45,100 --> 00:13:47,740 and he leads a very busy life. 122 00:13:55,660 --> 00:13:59,100 He eats parasites and dead skin from other fish... 123 00:14:00,740 --> 00:14:03,380 ..but he has to wait for them to come his way. 124 00:14:07,260 --> 00:14:09,780 And right now, no-one is stopping long enough 125 00:14:09,780 --> 00:14:11,500 to give him as much as a nibble. 126 00:14:23,500 --> 00:14:26,060 But then he spots something worth chasing... 127 00:14:30,220 --> 00:14:31,420 ..a batfish. 128 00:14:38,340 --> 00:14:42,100 Like a customer at a spa, the batfish lies back 129 00:14:42,100 --> 00:14:43,380 and waits for attention. 130 00:14:46,260 --> 00:14:47,340 It opens its gills 131 00:14:47,340 --> 00:14:50,900 and the cleaner wrasse bustles in to begin the treatment. 132 00:14:56,380 --> 00:15:00,260 The batfish even changes colour... 133 00:15:00,260 --> 00:15:02,900 probably to make parasites more visible. 134 00:15:08,780 --> 00:15:11,260 Someone else has arrived at the reef. 135 00:15:12,660 --> 00:15:14,300 The batfish is abandoned. 136 00:15:19,660 --> 00:15:21,780 There's a visitor from the open ocean 137 00:15:21,780 --> 00:15:24,020 that's worth dropping everything for. 138 00:15:32,780 --> 00:15:35,940 A manta ray, two metres long, 139 00:15:35,940 --> 00:15:38,860 has come back to a favourite stretch of reef. 140 00:15:51,940 --> 00:15:55,020 He signals to the manta by flicking his tail... 141 00:15:59,580 --> 00:16:03,580 ..and the giant responds by unfurling itself for cleaning. 142 00:16:09,740 --> 00:16:13,380 The manta keeps its feeding lobes rolled up while it swims... 143 00:16:17,940 --> 00:16:20,900 ..but a thorough clean keeps them parasite-free. 144 00:16:40,780 --> 00:16:43,740 This enormous fish would never visit Japan 145 00:16:43,740 --> 00:16:48,100 if it wasn't for the warmth that bathes the island chain... 146 00:16:48,100 --> 00:16:51,580 and the helpful services of this resourceful little wrasse. 147 00:16:56,860 --> 00:17:00,740 The Kuroshio Current brings more dangerous animals to the islands. 148 00:17:17,180 --> 00:17:18,780 Sea snakes. 149 00:17:20,300 --> 00:17:23,780 At one time, these snakes' ancestors lived on dry land. 150 00:17:24,980 --> 00:17:27,460 They must still visit the surface to breathe. 151 00:17:32,980 --> 00:17:36,660 But they are beautifully adapted to life at sea, 152 00:17:36,660 --> 00:17:38,900 hunting for fish around the island reefs. 153 00:17:44,980 --> 00:17:48,260 They have some of the most toxic venom of any animal, 154 00:17:48,260 --> 00:17:50,260 so they don't have many predators. 155 00:17:53,940 --> 00:17:57,580 But as they forage off the coast of one small island, 156 00:17:57,580 --> 00:18:00,140 their greatest nemesis is approaching. 157 00:18:14,660 --> 00:18:19,460 Yoko and Setsuko are hunters and they have a fearsome reputation. 158 00:18:24,620 --> 00:18:28,660 These two 70-year-olds are on a shopping trip like no other. 159 00:18:37,420 --> 00:18:40,740 Yoko and Setsuko live on the tiny island of Kudaka. 160 00:18:43,500 --> 00:18:47,740 It's only three miles across and, with limited space on land, 161 00:18:47,740 --> 00:18:50,420 the locals look to the sea to provide. 162 00:19:04,820 --> 00:19:08,340 As the sun sets, the ladies' prey is approaching. 163 00:19:18,700 --> 00:19:20,660 On certain summer nights, 164 00:19:20,660 --> 00:19:23,580 venomous sea snakes move towards the island 165 00:19:23,580 --> 00:19:25,260 and gather in coastal caves... 166 00:19:27,180 --> 00:19:29,820 ..looking for shelter and fresh water to drink. 167 00:19:39,780 --> 00:19:43,740 But coming ashore on this island is extremely risky. 168 00:20:06,660 --> 00:20:10,140 It takes some nerve to wade in with no protective clothing. 169 00:20:12,060 --> 00:20:15,900 Sea snake venom can be ten times more powerful than a rattlesnake's. 170 00:20:37,060 --> 00:20:40,700 Yoko has been hunting snakes for 40 years. 171 00:20:40,700 --> 00:20:43,100 It's a skill that's been passed down 172 00:20:43,100 --> 00:20:46,180 the generations here for at least five centuries. 173 00:21:23,540 --> 00:21:26,380 The snakes will be dried in this smokehouse 174 00:21:26,380 --> 00:21:29,420 using a secret process known only by the hunters. 175 00:21:37,780 --> 00:21:39,420 Then they go into a special soup. 176 00:21:45,700 --> 00:21:48,900 The catching and eating of sea snakes is a very old tradition 177 00:21:48,900 --> 00:21:53,020 on the island of Kudaka, where the sea provides more than the land. 178 00:21:54,820 --> 00:21:56,060 THEY SPEAK JAPANESE 179 00:22:00,900 --> 00:22:05,180 It's part of a rich island culture that goes back many centuries. 180 00:22:11,660 --> 00:22:16,060 Kudaka is just off the bigger island of Okinawa, 181 00:22:16,060 --> 00:22:18,180 right in the centre of the island chain. 182 00:22:26,140 --> 00:22:30,580 The seas are warm and bountiful, and the climate is perfect. 183 00:22:39,780 --> 00:22:41,980 In the Okinawan village of Ogimi, 184 00:22:41,980 --> 00:22:44,340 you are still considered young at 80. 185 00:22:45,820 --> 00:22:48,540 Many people here live well beyond 100. 186 00:23:03,100 --> 00:23:07,740 Okinawa is famous as a place where people live longer, 187 00:23:07,740 --> 00:23:09,900 an achievement worth celebrating. 188 00:23:30,100 --> 00:23:33,620 96-year-old Sumiko reckons it's all about staying active. 189 00:23:35,180 --> 00:23:37,620 She cycles to her vegetable garden every day. 190 00:23:41,700 --> 00:23:44,140 Others have their own theories. 191 00:23:50,220 --> 00:23:52,340 THEY LAUGH 192 00:23:52,340 --> 00:23:57,340 But the biggest influence of all, they say, is the Okinawan diet. 193 00:23:57,340 --> 00:23:59,580 Maybe this is what keeps them young. 194 00:24:09,900 --> 00:24:13,700 But there's one ingredient in their diet that can't be grown on land. 195 00:24:15,620 --> 00:24:17,860 It's another gift from the bountiful sea. 196 00:24:24,340 --> 00:24:27,620 Around Okinawa, the warm Kuroshio Current supports 197 00:24:27,620 --> 00:24:30,260 one of the strangest ways of farming in the world. 198 00:24:38,260 --> 00:24:42,220 The Tsuhako family have made their living from the sea for generations. 199 00:25:05,940 --> 00:25:08,820 It's harvest time on the family farm. 200 00:25:08,820 --> 00:25:10,460 ENGINE RUMBLES 201 00:25:32,780 --> 00:25:34,660 This is a field of mozuku. 202 00:25:36,660 --> 00:25:38,140 It's just humble seaweed, 203 00:25:38,140 --> 00:25:41,340 but it has a reputation as a miracle super food. 204 00:25:48,340 --> 00:25:49,780 It grows naturally, 205 00:25:49,780 --> 00:25:53,700 but Okinawan farmers have set out an ingenious system of nets 206 00:25:53,700 --> 00:25:55,340 to help it take root... 207 00:25:56,500 --> 00:25:59,620 ..and they have a very practical way of harvesting it. 208 00:26:12,220 --> 00:26:16,300 Mozuku seaweed is one of the most sought-after dishes in all Japan... 209 00:26:18,100 --> 00:26:20,340 ..so every strand is precious. 210 00:26:31,100 --> 00:26:34,540 This farming still relies on traditional Japanese wisdom. 211 00:26:36,620 --> 00:26:38,820 It's what they call satoumi. 212 00:26:40,060 --> 00:26:42,660 If you work harmoniously with nature, 213 00:26:42,660 --> 00:26:44,700 the sea will always provide. 214 00:26:49,180 --> 00:26:52,820 This is a man-made environment... 215 00:26:52,820 --> 00:26:55,780 but strange creatures roam the mozuku beds. 216 00:26:59,340 --> 00:27:02,900 Sea slugs. Some crawl... 217 00:27:04,380 --> 00:27:06,180 ..while others fly. 218 00:27:19,860 --> 00:27:24,500 This harmonious way of farming only works if the conditions are perfect. 219 00:27:26,660 --> 00:27:31,020 Warm water, plenty of nutrients... 220 00:27:31,020 --> 00:27:32,820 and a wide, shallow sea. 221 00:27:42,780 --> 00:27:46,980 It's only here in Okinawa that they can grow mozuku 222 00:27:46,980 --> 00:27:48,900 on such a massive scale. 223 00:28:05,740 --> 00:28:07,660 On these central islands, 224 00:28:07,660 --> 00:28:10,860 the bountiful sea provides a charmed way of life. 225 00:28:17,540 --> 00:28:20,580 But further south, life takes a different turn. 226 00:28:25,420 --> 00:28:28,820 Islands become further apart in the vastness of the ocean. 227 00:28:36,420 --> 00:28:38,740 With fewer human inhabitants, 228 00:28:38,740 --> 00:28:42,820 these are some of Japan's most remote island outposts. 229 00:28:48,220 --> 00:28:51,660 Increasing isolation brings a whole new set of challenges... 230 00:28:54,300 --> 00:28:57,340 ..and life has found ever more inventive ways to get by. 231 00:29:10,180 --> 00:29:12,580 One-and-a-half million years ago, 232 00:29:12,580 --> 00:29:15,420 the island of Iriomote was joined to the mainland. 233 00:29:19,900 --> 00:29:24,980 When sea levels rose and cut it off, one animal was left stranded here. 234 00:29:33,900 --> 00:29:36,740 Its descendants have been scratching a living in the island's 235 00:29:36,740 --> 00:29:38,900 dense forests ever since. 236 00:29:49,420 --> 00:29:51,180 A Ryukyu wild boar. 237 00:29:53,020 --> 00:29:56,060 It spends its day grubbing through the forest soils, 238 00:29:56,060 --> 00:29:57,860 digging up worms and roots, 239 00:29:57,860 --> 00:30:00,100 just like wild boar the world over. 240 00:30:04,580 --> 00:30:07,220 But life on this island is not always easy. 241 00:30:09,460 --> 00:30:11,540 It might look like paradise, 242 00:30:11,540 --> 00:30:14,220 but sometimes it's a struggle to find enough to eat. 243 00:30:26,340 --> 00:30:28,420 In the face of hardship, 244 00:30:28,420 --> 00:30:31,580 something remarkable happened to the Ryukyu wild boar. 245 00:30:33,220 --> 00:30:35,260 Over the generations, it has shrunk 246 00:30:35,260 --> 00:30:37,700 to half the size of its mainland cousins. 247 00:30:40,620 --> 00:30:43,580 When you're small, you need less energy to survive. 248 00:30:48,860 --> 00:30:53,340 They're now just knee-high - the tiniest wild boar in the world. 249 00:30:58,100 --> 00:31:01,060 But it still has a phenomenal sense of smell. 250 00:31:04,100 --> 00:31:05,500 BOAR SNIFFS 251 00:31:10,820 --> 00:31:13,740 It's alerted this little pig to a valuable bounty. 252 00:31:28,460 --> 00:31:31,100 A female green turtle has come back to the very beach 253 00:31:31,100 --> 00:31:32,940 where she was born. 254 00:31:35,820 --> 00:31:37,420 She's here to lay her eggs. 255 00:31:51,020 --> 00:31:52,940 Then she's off, back to the sea. 256 00:32:09,940 --> 00:32:12,580 A heavily pregnant and very hungry sow 257 00:32:12,580 --> 00:32:14,900 has come to the beach looking for eggs. 258 00:32:21,660 --> 00:32:23,300 But she's not the only one. 259 00:32:24,940 --> 00:32:27,380 A male is already rifling the nest. 260 00:32:37,340 --> 00:32:40,180 He certainly won't let her share. 261 00:32:40,180 --> 00:32:42,820 She can only eat when he's had his fill. 262 00:32:49,900 --> 00:32:51,340 BIRD CAWS 263 00:32:57,460 --> 00:33:00,300 But each nest can contain more than 100 eggs... 264 00:33:01,700 --> 00:33:03,340 ..so there's enough to go around. 265 00:33:14,100 --> 00:33:16,820 Cast away on these remote islands, 266 00:33:16,820 --> 00:33:19,380 you have to be extra resourceful to survive. 267 00:33:28,780 --> 00:33:32,580 On the tiniest islands, the challenges get more extreme. 268 00:33:34,020 --> 00:33:37,580 These are places where even pint-sized pigs can't survive. 269 00:33:39,300 --> 00:33:41,740 Islands like Tarama have been overrun 270 00:33:41,740 --> 00:33:43,540 by very different life forms... 271 00:33:45,060 --> 00:33:46,580 ..creatures of the sea. 272 00:33:54,740 --> 00:33:57,340 Blueberry hermit crabs, 273 00:33:57,340 --> 00:34:00,860 tropical crabs that have settled on these little islands. 274 00:34:10,900 --> 00:34:13,620 These crabs don't grow shells of their own. 275 00:34:13,620 --> 00:34:17,260 They make do with cast-offs from other sea creatures 276 00:34:17,260 --> 00:34:20,540 and they can only grow as big as their borrowed shell will allow. 277 00:34:23,380 --> 00:34:26,100 Deep in the forest, there's a very different crab... 278 00:34:29,060 --> 00:34:31,060 ..one that only comes out at night. 279 00:34:43,660 --> 00:34:45,700 A robber crab... 280 00:34:45,700 --> 00:34:48,260 the largest land crab in the world. 281 00:34:51,020 --> 00:34:53,900 On these islands, before people arrived, 282 00:34:53,900 --> 00:34:57,900 there were no big mammals and a humble crab could become king. 283 00:35:03,500 --> 00:35:04,820 They've become giants. 284 00:35:14,780 --> 00:35:19,420 Some can live for 60 years and grow to nearly a metre across. 285 00:35:23,180 --> 00:35:25,740 This female is only about 12 years old... 286 00:35:27,740 --> 00:35:29,460 ..so she still has a way to go 287 00:35:29,460 --> 00:35:32,220 before she's a true colossus of the crab world. 288 00:35:34,060 --> 00:35:36,900 But right now, she has a more pressing challenge. 289 00:35:39,140 --> 00:35:41,580 For several weeks, she's been nurturing 290 00:35:41,580 --> 00:35:43,620 thousands of eggs under her tail. 291 00:35:49,900 --> 00:35:52,940 But her babies need to start their lives in the ocean... 292 00:35:55,980 --> 00:35:57,620 ..so this young mum needs to make 293 00:35:57,620 --> 00:36:00,020 the most important journey of her life... 294 00:36:02,660 --> 00:36:05,740 ..and there are some very modern obstacles in her way. 295 00:36:09,380 --> 00:36:11,980 CAR RUMBLES 296 00:36:11,980 --> 00:36:13,980 DOG BARKS 297 00:36:13,980 --> 00:36:17,300 There's a small village between her forest home and the ocean. 298 00:36:23,820 --> 00:36:25,420 She must get to the sea in time 299 00:36:25,420 --> 00:36:27,660 for one of the highest tides of the year. 300 00:36:42,980 --> 00:36:47,180 But when she reaches the shore, she faces a dangerous situation. 301 00:36:54,900 --> 00:36:58,700 Robber crabs have become so big and heavy they can't swim. 302 00:37:07,500 --> 00:37:09,260 She needs to summon her nerve 303 00:37:09,260 --> 00:37:12,260 and wade out far enough to release her precious eggs. 304 00:37:14,620 --> 00:37:17,220 If she gets swept away, she'll drown. 305 00:37:28,620 --> 00:37:30,060 She's done it. 306 00:37:30,060 --> 00:37:33,300 She can get back to the safety of dry land... 307 00:37:34,900 --> 00:37:37,740 ..leaving her eggs to hatch in the warmth of the sea. 308 00:37:46,500 --> 00:37:48,500 But all this warmth comes at a price. 309 00:37:52,780 --> 00:37:55,420 Every summer, these Japanese islands 310 00:37:55,420 --> 00:37:58,060 are swept by violent tropical storms. 311 00:38:00,940 --> 00:38:06,220 They're born far out to sea and some grow into typhoons. 312 00:38:07,940 --> 00:38:09,740 The hurricanes of the Pacific. 313 00:38:14,940 --> 00:38:17,780 They draw energy from the warmth of the tropical sea 314 00:38:17,780 --> 00:38:20,620 and their power is enormous. 315 00:38:23,260 --> 00:38:26,500 If you're going to survive, you have to be fully prepared. 316 00:38:32,780 --> 00:38:36,060 Over thousands of years, people have built up defences. 317 00:38:37,140 --> 00:38:40,340 They've designed homes with high walls and sturdy roofs. 318 00:38:46,940 --> 00:38:50,260 Houses are decorated with Shisa lion dogs, 319 00:38:50,260 --> 00:38:53,940 ready to ward off evil spirits and impending disaster. 320 00:38:57,820 --> 00:38:59,820 All along the southwest islands, 321 00:38:59,820 --> 00:39:04,060 people and animals batten down the hatches as the storms build. 322 00:39:15,140 --> 00:39:17,900 In the forests, the macaques run for cover 323 00:39:17,900 --> 00:39:19,740 and huddle together for safety. 324 00:39:32,260 --> 00:39:35,140 But at the most south-westerly point of the island chain, 325 00:39:35,140 --> 00:39:39,740 one animal has come up with a more ingenious survival strategy. 326 00:39:44,060 --> 00:39:48,220 Yonaguni, 750 miles from the mainland, 327 00:39:48,220 --> 00:39:52,420 and often the first island to feel the full force of a typhoon. 328 00:40:04,060 --> 00:40:08,860 This far-flung speck of land is home to a very resourceful caterpillar. 329 00:40:27,180 --> 00:40:28,660 THUNDER RUMBLES 330 00:40:36,740 --> 00:40:38,940 It has built a typhoon-resistant shelter... 331 00:40:40,740 --> 00:40:44,220 ..an ingenious design of leaves and silk, 332 00:40:44,220 --> 00:40:47,660 woven together into a perfect defence against wind and rain. 333 00:40:54,980 --> 00:41:00,100 When they hit land, typhoon winds can reach 150mph. 334 00:42:14,020 --> 00:42:16,820 The giant cocoon has withstood the elements. 335 00:42:49,820 --> 00:42:52,180 The caterpillar has been transformed 336 00:42:52,180 --> 00:42:54,980 into one of the most striking animals on earth... 337 00:43:00,820 --> 00:43:02,340 ..an Atlas moth. 338 00:43:08,860 --> 00:43:11,820 She has a wingspan the size of a dinner plate. 339 00:43:14,220 --> 00:43:16,260 The largest moth in the world. 340 00:43:20,260 --> 00:43:22,220 Now that the typhoons have passed, 341 00:43:22,220 --> 00:43:26,940 she's come out for one purpose only - to attract a mate. 342 00:43:28,540 --> 00:43:30,900 She gives off pheromones from her tail. 343 00:43:36,460 --> 00:43:38,620 A male has picked up her scent. 344 00:43:49,020 --> 00:43:51,580 He'll fly three miles to find her. 345 00:44:03,300 --> 00:44:05,980 Once they've mated, their job is done. 346 00:44:08,100 --> 00:44:11,420 They don't even have mouths, so they will never eat. 347 00:44:22,780 --> 00:44:24,740 They only have a few days to live... 348 00:44:26,660 --> 00:44:29,300 ..but they have defeated the typhoon. 349 00:44:39,260 --> 00:44:41,940 This is a place of extreme survival, 350 00:44:41,940 --> 00:44:46,180 where the ocean, in all its moods, drives everything. 351 00:44:58,940 --> 00:45:04,020 Nowhere is that more evident than at the very furthest extent of Japan. 352 00:45:15,820 --> 00:45:18,700 Just below the surface lies a great mystery. 353 00:45:24,540 --> 00:45:27,820 The waters around Yonaguni are so remote, 354 00:45:27,820 --> 00:45:30,860 they've only been explored in the last few decades. 355 00:45:56,660 --> 00:46:01,620 In 1986, a local diver discovered something totally unexpected. 356 00:46:06,580 --> 00:46:09,220 He noticed strange features in the rock. 357 00:46:15,340 --> 00:46:18,980 He saw straight lines and flat surfaces. 358 00:46:30,540 --> 00:46:34,620 Here was what looked like a colossal underwater monument. 359 00:46:38,660 --> 00:46:45,380 A terraced sandstone pyramid, 270 metres long and 25 metres high. 360 00:46:53,420 --> 00:46:56,620 But who or what could have made it? 361 00:47:05,300 --> 00:47:08,740 Were those steps created for people to walk on? 362 00:47:15,660 --> 00:47:18,500 Some now believe these lines and surfaces 363 00:47:18,500 --> 00:47:20,500 were formed by nature alone. 364 00:47:26,260 --> 00:47:28,140 The simple shearing of rock 365 00:47:28,140 --> 00:47:31,300 in an area known for tremors and earthquakes. 366 00:47:34,780 --> 00:47:37,380 But others are convinced that this is a monument 367 00:47:37,380 --> 00:47:39,780 built by a lost civilisation... 368 00:47:42,020 --> 00:47:45,140 ..10,000 years ago, when sea levels were lower. 369 00:47:47,020 --> 00:47:50,260 If it is, this Atlantis of the Pacific 370 00:47:50,260 --> 00:47:53,020 would rewrite the history of these islands. 371 00:48:03,580 --> 00:48:05,020 We may never know the truth. 372 00:48:10,900 --> 00:48:13,860 But whether it was shaped by a lost civilisation 373 00:48:13,860 --> 00:48:16,580 or immense forces of nature, 374 00:48:16,580 --> 00:48:20,060 in the end, it was swallowed by the rising sea. 375 00:48:27,020 --> 00:48:31,460 All along this chain of islands, the sea is ultimately in control. 376 00:48:37,700 --> 00:48:41,580 But life has adapted to its fickle ways... 377 00:48:41,580 --> 00:48:44,460 making the most of opportunities while it can. 378 00:49:03,700 --> 00:49:05,980 We're in a cave by the sea. 379 00:49:05,980 --> 00:49:09,300 There's a 70-year-old lady down there catching sea snakes... 380 00:49:12,660 --> 00:49:13,980 ..with her bare hands! 381 00:49:16,940 --> 00:49:19,340 One of the team's more unusual experiences 382 00:49:19,340 --> 00:49:23,020 was on the island of Kudaka filming sea snake hunting. 383 00:49:30,340 --> 00:49:33,780 A privileged insight into the lives of two extraordinary women... 384 00:49:36,420 --> 00:49:38,540 ..who maintain an ancient tradition. 385 00:49:48,020 --> 00:49:50,420 The tiny island of Kudaka is just a short ferry ride 386 00:49:50,420 --> 00:49:52,260 from the main island of Okinawa. 387 00:49:54,180 --> 00:49:58,140 Producer David Marks and cameraman Robin Cox are keen to meet 388 00:49:58,140 --> 00:50:00,580 one of the island's legendary snake hunters... 389 00:50:01,860 --> 00:50:04,660 ..72-year-old Yoko Fukuchi. 390 00:50:04,660 --> 00:50:05,660 THEY SPEAK JAPANESE 391 00:50:13,180 --> 00:50:15,620 "You're very cute," that's what she's saying. 392 00:50:17,860 --> 00:50:20,220 It's a very quiet island. 393 00:50:20,220 --> 00:50:22,620 Fewer than 200 people live here. 394 00:50:26,820 --> 00:50:29,340 It's a place with a rich history and culture. 395 00:50:38,660 --> 00:50:42,220 Rituals like this are performed all year round to appease the gods 396 00:50:42,220 --> 00:50:43,660 and ward off misfortune. 397 00:50:43,660 --> 00:50:45,260 THEY SING 398 00:50:47,220 --> 00:50:50,980 Yoko and her friend Setsuko are not only hunters, 399 00:50:50,980 --> 00:50:54,540 they were once Kaminchu, priestesses of high status 400 00:50:54,540 --> 00:50:57,460 with special privileges to hunt snakes. 401 00:51:00,020 --> 00:51:04,420 They were made Kaminchu on this same patch of ground in 1978. 402 00:51:08,460 --> 00:51:11,820 The initiation ceremony was called Izaiho 403 00:51:11,820 --> 00:51:14,940 and this was the last time it was ever performed. 404 00:51:17,140 --> 00:51:20,460 As Japan has modernised, many traditions were lost. 405 00:51:22,660 --> 00:51:24,420 After more than five centuries, 406 00:51:24,420 --> 00:51:27,820 Yoko and Setsuko are now the last in their line 407 00:51:27,820 --> 00:51:29,140 who know the old ways. 408 00:51:33,220 --> 00:51:35,660 Sea snakes have been hunted here for centuries. 409 00:51:37,260 --> 00:51:39,700 It's another tradition that may soon be lost. 410 00:52:00,820 --> 00:52:04,500 Despite their age, Yoko and Setsuko are the only ones left 411 00:52:04,500 --> 00:52:06,140 on the island who still hunt. 412 00:52:14,940 --> 00:52:18,420 The team has been granted special permission to film them, 413 00:52:18,420 --> 00:52:22,300 but they have to work in the dark so they don't scare off the snakes. 414 00:52:24,300 --> 00:52:26,140 (I can see about 20 snakes in here.) 415 00:52:31,500 --> 00:52:33,140 (She gets right to the back of the cave.) 416 00:52:34,540 --> 00:52:37,220 For Yoko and Setsuko, this ancient way of hunting 417 00:52:37,220 --> 00:52:39,220 requires intense concentration. 418 00:52:46,140 --> 00:52:48,980 The nearest hospital is across the water in Okinawa, 419 00:52:48,980 --> 00:52:52,220 so if the ladies were bitten they probably wouldn't survive. 420 00:52:58,540 --> 00:53:00,980 As the snakes swim in on the surge of water, 421 00:53:00,980 --> 00:53:03,340 the ladies pick them out with their torches. 422 00:53:13,620 --> 00:53:15,180 But years of experience mean 423 00:53:15,180 --> 00:53:18,300 they can sense the movement of the snakes in the dark. 424 00:53:23,700 --> 00:53:25,540 Yoko's poised to strike. 425 00:53:34,700 --> 00:53:36,900 She's got a massive snake in her hands. 426 00:53:39,780 --> 00:53:43,260 The team want to get shots of Yoko actually catching the snakes, 427 00:53:43,260 --> 00:53:46,060 but with such a cramped space to work in 428 00:53:46,060 --> 00:53:48,100 they need some special technology. 429 00:53:50,740 --> 00:53:52,140 What does it say? 430 00:53:52,140 --> 00:53:53,580 It's not saying anything. 431 00:53:54,980 --> 00:53:58,860 Basically, we're trying to get the camera and my smartphone to 432 00:53:58,860 --> 00:54:02,300 talk to each other so we can put the camera in the water where the 433 00:54:02,300 --> 00:54:05,780 sea snakes are, and we can turn it on and off and focus and do all 434 00:54:05,780 --> 00:54:09,740 the things we need it to do with it, but at the moment it's not working. 435 00:54:09,740 --> 00:54:11,860 Well, she got another one. 436 00:54:11,860 --> 00:54:15,420 So while we've got all this ridiculous technological nonsense 437 00:54:15,420 --> 00:54:18,180 going on, Yoko is just happily plucking the odd snake 438 00:54:18,180 --> 00:54:20,500 out of the water every five or ten minutes. 439 00:54:21,700 --> 00:54:27,300 It's working, yay. Look at that. It looks good. 440 00:54:27,300 --> 00:54:29,340 With the technical problems solved, 441 00:54:29,340 --> 00:54:31,580 someone has to actually get in the cave. 442 00:54:33,020 --> 00:54:36,860 David has volunteered, but he'll need some protection. 443 00:54:36,860 --> 00:54:39,060 Yoko is not wearing any gloves. 444 00:54:39,060 --> 00:54:40,820 No, Yoko doesn't wear gloves, 445 00:54:40,820 --> 00:54:43,580 but I'm not putting my hands in water with sea snakes 446 00:54:43,580 --> 00:54:45,580 crawling everywhere without any gloves on. 447 00:54:48,340 --> 00:54:49,820 YOKO LAUGHS 448 00:54:49,820 --> 00:54:52,060 What's so funny? 449 00:54:52,060 --> 00:54:53,540 Why are you laughing? 450 00:54:53,540 --> 00:54:54,900 Why are you laughing, Yoko? 451 00:55:00,820 --> 00:55:02,620 When the night's hunting is over, 452 00:55:02,620 --> 00:55:05,900 the team discover they only got a few shots of Yoko's legs. 453 00:55:21,980 --> 00:55:25,580 The next day, the team are invited to Yoko's house. 454 00:55:25,580 --> 00:55:28,060 She's prepared snake soup for them to eat. 455 00:55:33,940 --> 00:55:36,380 We're filming... 456 00:55:36,380 --> 00:55:38,820 snake and now it's time to eat snake. 457 00:55:41,260 --> 00:55:45,300 I'm resisting the urge to say it tastes like chicken. 458 00:55:45,300 --> 00:55:47,740 It doesn't taste like chicken. 459 00:55:47,740 --> 00:55:49,380 It's pretty smoky, isn't it? 460 00:55:49,380 --> 00:55:50,420 It's a bit snaky. 461 00:55:55,940 --> 00:55:59,660 For the team, it's an unusual meal, but it's a great honour. 462 00:55:59,660 --> 00:56:03,020 This dish was once reserved only for the island's kings. 463 00:56:09,860 --> 00:56:12,740 There is only one night of filming left. 464 00:56:12,740 --> 00:56:16,380 The team haven't yet got the shots they need of Yoko hunting, 465 00:56:16,380 --> 00:56:20,300 but they have discovered a second entrance to the cramped cave. 466 00:56:23,900 --> 00:56:28,020 Unlike the ladies, cameraman Robin is taking all precautions. 467 00:56:29,180 --> 00:56:30,740 Put the hood on. There you go! 468 00:56:32,620 --> 00:56:34,900 He's squeezed himself into a tiny 469 00:56:34,900 --> 00:56:38,860 hole and is now surrounded by venomous sea snakes, 470 00:56:38,860 --> 00:56:42,380 but he's finally in a position to capture the action. 471 00:56:57,820 --> 00:57:01,500 OK, she just got a pretty big snake. 472 00:57:01,500 --> 00:57:04,740 Just saw it just swimming underneath my feet here 473 00:57:04,740 --> 00:57:08,580 and then it went in a crack in the rock and she came and grabbed it, 474 00:57:08,580 --> 00:57:10,180 caught it and stuffed it in her bag, 475 00:57:10,180 --> 00:57:12,620 so I think we've got the shots that we were waiting for 476 00:57:12,620 --> 00:57:15,300 and I think I can get out of here now, please. 477 00:57:20,780 --> 00:57:24,420 It's been a successful night for Yoko and Setsuko too. 478 00:57:27,260 --> 00:57:29,500 That was astonishing. Pretty amazing. 479 00:57:32,340 --> 00:57:33,980 I mean, can you imagine...? 480 00:57:33,980 --> 00:57:38,220 My mum, most evenings, has a glass of wine or two and watches some telly. 481 00:57:38,220 --> 00:57:40,700 You can't imagine your mum knee-deep in water, 482 00:57:40,700 --> 00:57:44,540 writhing with deadly snakes, picking them up and putting them in a bag. 483 00:58:02,180 --> 00:58:07,460 Next time, we head to Hokkaido - Japan's northern frontier. 484 00:58:09,500 --> 00:58:11,860 Life is ruled by its extreme seasons. 485 00:58:15,180 --> 00:58:16,820 Survival means being tough... 486 00:58:16,820 --> 00:58:17,820 BIRDS SQUAWK 487 00:58:20,500 --> 00:58:21,900 BIRD SQUAWKS 488 00:58:21,900 --> 00:58:23,780 ..and forging unlikely alliances. 489 00:58:27,060 --> 00:58:29,220 It's Japan's wildest island.