1 00:00:27,200 --> 00:00:29,220 A Perfect Planet. 2 00:00:38,620 --> 00:00:43,100 There is a nuclear reactor 93 million miles away. 3 00:00:47,700 --> 00:00:49,660 We call it the Sun. 4 00:00:51,940 --> 00:00:55,180 Its rays, travelling through space, 5 00:00:55,180 --> 00:00:58,260 reach the Earth in just eight minutes... 6 00:01:00,700 --> 00:01:04,340 ..and give power to life throughout the planet. 7 00:01:09,740 --> 00:01:13,020 Its daily and yearly rhythms 8 00:01:13,020 --> 00:01:16,940 shape the existence of every creature on Earth... 9 00:01:20,820 --> 00:01:25,020 ..and has done so for over three billion years. 10 00:01:36,220 --> 00:01:37,860 In the beginning... 11 00:01:39,420 --> 00:01:41,700 ..there was light. 12 00:01:56,780 --> 00:02:01,060 Surprisingly, perhaps, almost every part of the Earth's surface 13 00:02:01,060 --> 00:02:05,460 receives the same quantity of sunlight each year... 14 00:02:06,980 --> 00:02:10,340 ..4,380 hours of it. 15 00:02:13,220 --> 00:02:16,020 But it's delivered in varying amounts 16 00:02:16,020 --> 00:02:18,340 at different times of the year, 17 00:02:18,340 --> 00:02:20,580 depending on where you are. 18 00:02:25,540 --> 00:02:29,340 It's only here in the tropics, close to the equator, 19 00:02:29,340 --> 00:02:33,260 that there are 12 hours of guaranteed daily sunlight 20 00:02:33,260 --> 00:02:34,500 the year round. 21 00:02:38,980 --> 00:02:43,580 And, here, that has created a great richness of life - 22 00:02:43,580 --> 00:02:45,420 the tropical forest. 23 00:02:48,980 --> 00:02:53,940 Each leaf is a natural solar panel which collects the sun's energy 24 00:02:53,940 --> 00:02:57,260 and fuels a multitude of plants. 25 00:02:59,380 --> 00:03:02,780 And, in Southeast Asia, gibbons live here. 26 00:03:06,420 --> 00:03:09,740 WHOOPING 27 00:03:09,740 --> 00:03:11,140 BIRD CALLS 28 00:03:11,140 --> 00:03:14,140 A five-year-old female... 29 00:03:15,820 --> 00:03:19,220 ..and her lifelong partner are on a mission. 30 00:03:24,940 --> 00:03:28,020 Every morning, they head out across their territory 31 00:03:28,020 --> 00:03:29,380 to look for ripe fruit. 32 00:03:37,180 --> 00:03:41,340 There is one kind of tree here that they need more than any other. 33 00:03:46,340 --> 00:03:47,540 The fig tree. 34 00:03:53,180 --> 00:03:58,020 These are the only plants in the entire forest that produce fruit 35 00:03:58,020 --> 00:04:00,260 all year round. 36 00:04:00,260 --> 00:04:03,500 Their flowers grow in dense clusters 37 00:04:03,500 --> 00:04:07,180 inside undeveloped figs, 38 00:04:07,180 --> 00:04:09,820 but these have not yet been pollinated 39 00:04:09,820 --> 00:04:11,980 and are not yet edible. 40 00:04:11,980 --> 00:04:14,860 The gibbons will have to wait. 41 00:04:19,420 --> 00:04:23,460 To produce ripe fruit, the fig still needs two things... 42 00:04:24,620 --> 00:04:27,300 ..a large dose of sunlight 43 00:04:27,300 --> 00:04:30,900 and some of the smallest creatures in the forest. 44 00:04:33,780 --> 00:04:36,620 Tiny fig wasps. 45 00:04:36,620 --> 00:04:39,460 They're only 2mm long. 46 00:04:41,700 --> 00:04:45,940 The figs have a unique partnership with these insects. 47 00:04:48,380 --> 00:04:52,380 A female wasp has the space of just a single day 48 00:04:52,380 --> 00:04:56,940 when the fig will allow her to burrow into the undeveloped fruit. 49 00:04:58,380 --> 00:05:02,220 It's such a tight squeeze that her wings are ripped off. 50 00:05:04,540 --> 00:05:08,060 But she's not going to use them again. 51 00:05:11,100 --> 00:05:14,300 Once inside, she makes her way to the tiny, 52 00:05:14,300 --> 00:05:17,060 tightly packed internal flowers. 53 00:05:20,780 --> 00:05:24,140 And, here within, she lays hundreds of eggs. 54 00:05:26,620 --> 00:05:30,900 She then carefully unpacks fig pollen from her abdomen... 55 00:05:33,380 --> 00:05:36,740 ..and with it fertilises the tiny flowers. 56 00:05:39,180 --> 00:05:40,780 When she's finished laying, 57 00:05:40,780 --> 00:05:43,220 she dies... 58 00:05:43,220 --> 00:05:45,780 ..inside the unripe fig 59 00:05:45,780 --> 00:05:48,780 alongside her eggs. 60 00:05:50,900 --> 00:05:54,420 The sunlight now slowly ripens the figs 61 00:05:54,420 --> 00:05:57,620 and helps the young wasps inside to develop. 62 00:06:00,420 --> 00:06:04,980 After just five weeks, the eggs start to hatch. 63 00:06:06,340 --> 00:06:10,260 The first to emerge are the golden, wingless males. 64 00:06:13,540 --> 00:06:16,860 Things now become stranger than fiction. 65 00:06:20,340 --> 00:06:25,100 These males start to mate with their unhatched sisters. 66 00:06:27,740 --> 00:06:31,780 To reach them, they use a telescopic penis 67 00:06:31,780 --> 00:06:33,860 that's twice their body length. 68 00:06:43,420 --> 00:06:47,660 While their now-pregnant sisters are beginning to hatch, 69 00:06:47,660 --> 00:06:52,700 the males themselves burrow their way to the outside world. 70 00:07:08,980 --> 00:07:12,780 The brothers' final act is a chivalrous one. 71 00:07:17,540 --> 00:07:22,740 They sacrifice themselves to marauding ants. 72 00:07:27,140 --> 00:07:29,100 They're serving as decoys 73 00:07:29,100 --> 00:07:31,700 so their sisters can take to the skies. 74 00:07:36,580 --> 00:07:40,660 The young females, loaded with pollen, live for just 48 hours, 75 00:07:40,660 --> 00:07:46,140 in which time they must find another fig tree at just the right stage 76 00:07:46,140 --> 00:07:50,460 into which they themselves can burrow, as their mothers did. 77 00:07:54,660 --> 00:07:58,660 With the sun's helping hand, the figs are now ready to eat. 78 00:08:07,700 --> 00:08:11,020 The gibbons know all the fig trees in their territory. 79 00:08:12,620 --> 00:08:16,100 And each day they travel up to two miles 80 00:08:16,100 --> 00:08:19,860 to find one with fruit that's ready to eat. 81 00:08:28,580 --> 00:08:31,620 Ripe figs at last... 82 00:08:32,900 --> 00:08:36,620 ..a major part of their diet and available the year round. 83 00:08:41,060 --> 00:08:44,220 Thousands of animals rely on fig trees. 84 00:08:48,740 --> 00:08:54,660 This abundance is only possible in a world without seasons 85 00:08:54,660 --> 00:08:57,420 and constant daily sunlight. 86 00:09:05,300 --> 00:09:08,700 But this 12-hour cycle of light and darkness 87 00:09:08,700 --> 00:09:11,420 only happens close to the equator. 88 00:09:13,500 --> 00:09:17,340 Elsewhere, the amount of sunlight fluctuates across the year. 89 00:09:19,580 --> 00:09:24,420 That is because the Earth does not spin in an upright way. 90 00:09:24,420 --> 00:09:27,500 Its axis is on a tilt. 91 00:09:27,500 --> 00:09:30,260 23.5 degrees. 92 00:09:31,740 --> 00:09:35,620 So as the Earth makes its annual orbit around the Sun, 93 00:09:35,620 --> 00:09:38,260 keep your eye on the North Pole. 94 00:09:40,260 --> 00:09:44,380 For the first half of the year, it's angled away from the Sun, 95 00:09:44,380 --> 00:09:48,420 bringing darkness and winter to the northern hemisphere. 96 00:09:48,420 --> 00:09:50,740 For the second part of the year, 97 00:09:50,740 --> 00:09:54,940 the North Pole swings towards the Sun, bringing summer. 98 00:09:58,100 --> 00:10:00,900 The Earth's tilt gives us the seasons. 99 00:10:04,460 --> 00:10:06,180 And life has adapted 100 00:10:06,180 --> 00:10:10,340 to deal with even the most extreme changes in light. 101 00:10:11,900 --> 00:10:13,860 The High Arctic. 102 00:10:13,860 --> 00:10:17,180 After six months of being angled towards the Sun, 103 00:10:17,180 --> 00:10:21,100 it begins six months of freezing darkness. 104 00:10:27,420 --> 00:10:30,260 This is Ellesmere Island, 105 00:10:30,260 --> 00:10:32,700 the closest land to the North Pole. 106 00:10:34,420 --> 00:10:38,500 It's winter, and for the last four, long months, 107 00:10:38,500 --> 00:10:42,260 the only light here has come from the Moon. 108 00:10:44,580 --> 00:10:48,300 Few creatures can survive this sustained darkness. 109 00:10:49,580 --> 00:10:54,660 They have become specialists in living for months without sunlight. 110 00:10:54,660 --> 00:10:57,060 WIND HOWLS 111 00:10:59,300 --> 00:11:00,940 Muskox. 112 00:11:00,940 --> 00:11:03,420 Remnants of the last Ice Age. 113 00:11:08,260 --> 00:11:12,140 Having grazed all summer, they've built up fat reserves 114 00:11:12,140 --> 00:11:15,540 that will enable them to survive the brutal cold of winter. 115 00:11:18,220 --> 00:11:23,660 And this makes them a prime target for other sub-zero specialists. 116 00:11:32,180 --> 00:11:34,460 GROWLING 117 00:11:34,460 --> 00:11:36,700 Arctic wolves. 118 00:11:39,380 --> 00:11:43,860 The Moon provides just enough light for them to see. 119 00:11:48,060 --> 00:11:49,980 SHE SNIFFS 120 00:11:52,300 --> 00:11:55,900 This alpha female leads the hunt. 121 00:12:02,020 --> 00:12:04,100 Target in sight. 122 00:12:05,580 --> 00:12:10,500 If her pack is to survive, they need to make a large kill 123 00:12:10,500 --> 00:12:13,660 at least once every three weeks. 124 00:12:25,140 --> 00:12:29,100 The alpha female signals the start of the attack. 125 00:12:41,700 --> 00:12:46,140 They run at the muskox and the herd panics. 126 00:12:59,380 --> 00:13:02,020 The muskox close ranks. 127 00:13:05,860 --> 00:13:08,820 The wolves look for weakness. 128 00:13:10,540 --> 00:13:12,700 MUSKOX ROARS 129 00:13:17,420 --> 00:13:19,860 IT ROARS FIERCELY 130 00:13:19,860 --> 00:13:21,340 WOLVES WHINE 131 00:13:24,140 --> 00:13:27,980 Charging risks isolation from the crowd. 132 00:13:27,980 --> 00:13:29,820 ROARING 133 00:13:34,140 --> 00:13:37,140 And that is just what the wolf pack wants. 134 00:13:37,140 --> 00:13:39,580 ROARING 135 00:13:55,020 --> 00:13:57,460 The wolves can sense victory. 136 00:14:13,100 --> 00:14:15,540 But the herd comes to the rescue. 137 00:14:23,900 --> 00:14:27,500 And, once again, they close ranks. 138 00:14:31,020 --> 00:14:35,660 Most winter hunts end in failure for the wolves. 139 00:14:35,660 --> 00:14:37,460 MUSKOX ROARS, WOLVES WHINE 140 00:14:47,020 --> 00:14:50,100 As the long polar nights drag on, 141 00:14:50,100 --> 00:14:55,060 the hungry wolves turn to their only other source of food... 142 00:14:58,180 --> 00:15:00,780 ..arctic hares. 143 00:15:08,980 --> 00:15:12,820 They've gathered together in their hundreds for safety. 144 00:15:30,500 --> 00:15:33,140 Trying to catch one hare among hundreds 145 00:15:33,140 --> 00:15:35,340 is harder than you might think. 146 00:15:41,540 --> 00:15:45,700 Even if they do catch one, it's not much of a meal. 147 00:15:56,700 --> 00:16:00,580 Sometimes you just have to admit defeat. 148 00:16:06,620 --> 00:16:09,460 WOLF GROWLS 149 00:16:11,340 --> 00:16:14,900 But life is about to get better for the wolves. 150 00:16:26,980 --> 00:16:33,260 For the first time in six months, the sun rises above the horizon. 151 00:16:42,820 --> 00:16:48,900 Its appearance marks the beginning of half a year of continuous light. 152 00:16:51,220 --> 00:16:56,100 The sun's warmth will allow the muskox to give birth, 153 00:16:56,100 --> 00:17:01,260 and that will provide easier hunting for the wolves. 154 00:17:13,500 --> 00:17:15,740 It's early spring, 155 00:17:15,740 --> 00:17:20,180 and much of North America is still locked in ice. 156 00:17:23,540 --> 00:17:26,500 As our tilted planet orbits the Sun, 157 00:17:26,500 --> 00:17:30,100 the northern hemisphere receives increasing sunlight... 158 00:17:33,220 --> 00:17:37,620 ..and wakens an animal with an almost supernatural ability. 159 00:17:46,180 --> 00:17:48,940 It is frozen solid, 160 00:17:48,940 --> 00:17:50,860 like a block of ice, 161 00:17:50,860 --> 00:17:53,700 and has been all winter. 162 00:17:56,940 --> 00:17:58,780 An ordinary-looking frog... 163 00:18:00,820 --> 00:18:03,220 ..but an extraordinary one. 164 00:18:04,380 --> 00:18:06,060 A wood frog. 165 00:18:07,340 --> 00:18:10,140 Its heart has stopped beating completely. 166 00:18:15,780 --> 00:18:17,940 But, as the sun's power increases, 167 00:18:17,940 --> 00:18:21,100 almost miraculously, it begins to change. 168 00:18:30,260 --> 00:18:32,540 Its frozen blood is melting 169 00:18:32,540 --> 00:18:35,740 and begins to flow through its veins... 170 00:18:38,420 --> 00:18:42,020 ..as its heart begins to beat again. 171 00:18:42,020 --> 00:18:45,540 HEARTBEAT 172 00:18:49,340 --> 00:18:52,580 The wood frog is cryogenic. 173 00:18:55,500 --> 00:18:58,020 In just 12 hours, 174 00:18:58,020 --> 00:19:02,380 it thaws and comes back to life, as if by magic. 175 00:19:07,340 --> 00:19:09,340 This defrosting ability 176 00:19:09,340 --> 00:19:13,260 means it's ready for the moment when, at last, 177 00:19:13,260 --> 00:19:15,740 spring arrives. 178 00:19:19,220 --> 00:19:21,700 All across the northern hemisphere, 179 00:19:21,700 --> 00:19:24,900 the sun's warmth is bringing dramatic change. 180 00:19:48,700 --> 00:19:52,540 As the sun rises higher and spring takes hold, 181 00:19:52,540 --> 00:19:56,380 the warming air reaches the ground and the rocks beneath. 182 00:20:01,540 --> 00:20:05,580 Here, thousands of animals begin to stir. 183 00:20:09,580 --> 00:20:11,340 Garter snakes, 184 00:20:11,340 --> 00:20:14,980 one of Canada's most northerly reptiles. 185 00:20:17,300 --> 00:20:19,740 After six months of hibernation, 186 00:20:19,740 --> 00:20:22,460 the males are the first to emerge. 187 00:20:23,580 --> 00:20:26,660 They haven't eaten for months. 188 00:20:26,660 --> 00:20:31,780 Even so, it's not food that is on their minds, it's something else... 189 00:20:33,740 --> 00:20:36,260 ..females. 190 00:20:36,260 --> 00:20:40,060 But they stand no chance of doing anything about that 191 00:20:40,060 --> 00:20:42,900 until they've charged their batteries. 192 00:20:49,420 --> 00:20:53,660 Snakes are cold-blooded and they need to absorb the sun's heat 193 00:20:53,660 --> 00:20:56,300 before they're able to move quickly. 194 00:21:02,660 --> 00:21:06,380 After a few hours, the males are raring to go. 195 00:21:10,220 --> 00:21:12,660 20,000 snakes, 196 00:21:12,660 --> 00:21:15,140 the largest emergence of reptiles 197 00:21:15,140 --> 00:21:17,620 anywhere on Earth. 198 00:21:31,860 --> 00:21:35,180 Now a few females appear. 199 00:21:38,780 --> 00:21:41,260 They're much bigger than the males... 200 00:21:43,500 --> 00:21:46,220 ..and warming will take them longer. 201 00:21:47,460 --> 00:21:49,540 She releases a scent, a pheromone, 202 00:21:49,540 --> 00:21:52,580 that attracts the males. 203 00:21:52,580 --> 00:21:55,820 They outnumber her 100 to one. 204 00:21:59,780 --> 00:22:04,940 To speed her own return to activity, she will absorb heat from them. 205 00:22:12,260 --> 00:22:15,220 Intoxicated by her scent, the males compete for her, 206 00:22:15,220 --> 00:22:18,580 wrapping themselves around her. 207 00:22:36,060 --> 00:22:39,300 She now has hundreds of males on top of her, 208 00:22:39,300 --> 00:22:41,660 making mating near impossible. 209 00:22:43,100 --> 00:22:47,020 But she has a way of weeding out the men from the boys. 210 00:22:49,540 --> 00:22:54,100 She'll make a daring ascent of the nearby cliff. 211 00:22:56,980 --> 00:23:01,620 She barges her way through the crowd to get to the rock face. 212 00:23:12,780 --> 00:23:17,660 As she climbs, only the strongest, fittest males can keep up with her. 213 00:23:52,940 --> 00:23:55,180 She's made it to the top. 214 00:23:55,180 --> 00:24:00,180 Only a few of her suitors have managed to rise to the occasion, 215 00:24:00,180 --> 00:24:03,380 and she may reward them all. 216 00:24:09,100 --> 00:24:12,620 This entire mating jamboree only lasts 217 00:24:12,620 --> 00:24:16,060 for one short week in the year. 218 00:24:22,260 --> 00:24:26,580 And when it's over, they all move off into the forest. 219 00:24:29,020 --> 00:24:34,300 There, they disperse to lead solitary lives searching for food 220 00:24:34,300 --> 00:24:39,940 until winter drives them back to the shelter of the rocks below ground. 221 00:24:48,900 --> 00:24:52,780 It's June, halfway through the Earth's annual journey 222 00:24:52,780 --> 00:24:58,020 around the sun, and summer has arrived in the northern hemisphere. 223 00:25:02,340 --> 00:25:07,140 Karak Lake, in Canada, north of the Arctic Circle. 224 00:25:08,980 --> 00:25:11,060 The summer will be brief, 225 00:25:11,060 --> 00:25:14,460 but there is sunlight for 24 hours every day. 226 00:25:17,460 --> 00:25:22,380 So the next few months are vital for every living thing here. 227 00:25:27,900 --> 00:25:31,100 And this arctic fox knows it. 228 00:25:34,380 --> 00:25:36,020 CUBS SQUEAK 229 00:25:37,860 --> 00:25:43,780 Winter has been hard for her, and now with a new family to support, 230 00:25:43,780 --> 00:25:47,620 she must make the most of the summer's abundance. 231 00:25:52,380 --> 00:25:56,740 Her three-week-old pups have just emerged from the den. 232 00:26:03,180 --> 00:26:05,140 CUBS SQUEAL 233 00:26:08,100 --> 00:26:10,580 Each of these little bundles of fur 234 00:26:10,580 --> 00:26:15,220 needs nearly 300 calories of food every day. 235 00:26:17,660 --> 00:26:19,700 A tall order for Mum. 236 00:26:20,700 --> 00:26:22,380 GEESE HONK 237 00:26:22,380 --> 00:26:25,380 But a solution for her problem is just arriving. 238 00:26:28,620 --> 00:26:30,500 Snow geese. 239 00:26:30,500 --> 00:26:35,180 They have flown over a thousand miles from the United States, 240 00:26:35,180 --> 00:26:39,620 timing their arrival to coincide with the end of the snow. 241 00:26:39,620 --> 00:26:43,380 GEESE HONK 242 00:26:52,220 --> 00:26:55,540 More than half a million will spend the summer here, 243 00:26:55,540 --> 00:26:57,860 nesting and feeding on the grass. 244 00:26:59,740 --> 00:27:02,660 There's fierce competition between couples 245 00:27:02,660 --> 00:27:04,780 for the safest nesting sites. 246 00:27:13,540 --> 00:27:18,260 The losers will have to nest on the outskirts of the colony... 247 00:27:18,260 --> 00:27:21,780 ..the first part to be raided by the foxes. 248 00:27:38,500 --> 00:27:42,820 Mother is after eggs... 249 00:27:42,820 --> 00:27:46,020 ..but getting them is not going to be easy. 250 00:27:53,580 --> 00:27:57,260 GEESE HONK 251 00:28:05,980 --> 00:28:10,580 The geese will risk their lives to protect their eggs. 252 00:28:10,580 --> 00:28:15,060 If they lose them, they can't produce another clutch this season. 253 00:28:20,540 --> 00:28:22,820 The fox wins. 254 00:28:24,820 --> 00:28:27,940 GEESE CALL 255 00:28:31,380 --> 00:28:34,660 She gives the first eggs to her young pups... 256 00:28:38,900 --> 00:28:41,660 ..and then heads back for more. 257 00:28:53,900 --> 00:28:56,940 GEESE HONK 258 00:29:05,780 --> 00:29:09,100 Some of the eggs she stashes away. 259 00:29:12,380 --> 00:29:15,820 They will be food to help her through the coming winter. 260 00:29:15,820 --> 00:29:18,100 GOOSE HONKS 261 00:29:34,540 --> 00:29:40,380 In just three weeks, she will steal over 800 eggs from the geese. 262 00:29:51,540 --> 00:29:54,620 But eating a big egg is not easy 263 00:29:54,620 --> 00:29:56,980 if one is rather small. 264 00:30:00,500 --> 00:30:05,100 It's a technique the pups haven't quite yet cracked. 265 00:30:06,340 --> 00:30:09,380 Mum shows how it's done. 266 00:30:18,980 --> 00:30:21,660 GOSLING CHEEPS 267 00:30:21,660 --> 00:30:25,660 Goslings are now hatching all across the colony. 268 00:30:27,940 --> 00:30:30,580 And they will need all the food they can get 269 00:30:30,580 --> 00:30:33,940 to build up their fat before their journey south. 270 00:30:36,620 --> 00:30:38,700 Now that the chicks have hatched, 271 00:30:38,700 --> 00:30:41,500 they can all find safety on the water. 272 00:30:49,460 --> 00:30:51,140 CUBS SQUEAL 273 00:30:51,140 --> 00:30:55,820 In these brief sunlit months, there's time for the cubs to play. 274 00:30:58,700 --> 00:31:01,620 But there is no playtime for Mum. 275 00:31:15,460 --> 00:31:18,420 But the Arctic is warming, 276 00:31:18,420 --> 00:31:21,780 and the timing of the seasons and the migration of the geese 277 00:31:21,780 --> 00:31:23,980 is becoming unpredictable. 278 00:31:31,740 --> 00:31:34,860 Although the sun stays above the horizon continuously 279 00:31:34,860 --> 00:31:37,420 throughout the Arctic summer, 280 00:31:37,420 --> 00:31:40,820 its rays are comparatively feeble. 281 00:31:43,900 --> 00:31:47,340 Closer to the equator, in our planet's deserts, 282 00:31:47,340 --> 00:31:49,820 cloud cover is rare. 283 00:32:02,580 --> 00:32:05,940 The sun here is not a friend... 284 00:32:05,940 --> 00:32:08,060 ..but an enemy. 285 00:32:14,140 --> 00:32:17,380 WIND GUSTS 286 00:32:17,380 --> 00:32:19,060 Africa. 287 00:32:20,180 --> 00:32:22,260 The Sahara. 288 00:32:26,100 --> 00:32:28,780 Few creatures can live here. 289 00:32:32,860 --> 00:32:36,420 Get caught out in the open at the wrong time of day 290 00:32:36,420 --> 00:32:38,940 and it's game over. 291 00:32:38,940 --> 00:32:41,140 WIND GUSTS 292 00:32:44,860 --> 00:32:47,700 By 10:00 in the morning, the temperature on the surface 293 00:32:47,700 --> 00:32:51,020 of the sand is pushing 60 degrees Celsius. 294 00:32:52,540 --> 00:32:56,540 Even the toughest will soon have to take cover. 295 00:33:00,860 --> 00:33:03,860 But one creature is waiting underground 296 00:33:03,860 --> 00:33:06,740 for the sun to get even hotter. 297 00:33:12,860 --> 00:33:15,100 Temperatures are now so high 298 00:33:15,100 --> 00:33:18,260 that everything else has to shelter. 299 00:33:24,500 --> 00:33:29,900 The desert now belongs to the Earth's greatest solar specialist... 300 00:33:31,340 --> 00:33:34,580 ..the Saharan silver ant. 301 00:33:36,780 --> 00:33:40,300 At midday, when the sun is at its fiercest, 302 00:33:40,300 --> 00:33:44,500 they emerge to look for creatures killed by the scorching heat. 303 00:33:46,500 --> 00:33:50,380 They're one of the fastest insects on Earth, and they need to be, 304 00:33:50,380 --> 00:33:54,060 with just five minutes to find food before the heat kills them. 305 00:33:58,380 --> 00:34:01,420 Getting lost would mean certain death, 306 00:34:01,420 --> 00:34:04,020 so every few seconds they spin round, 307 00:34:04,020 --> 00:34:06,420 taking a bearing from the sun. 308 00:34:15,100 --> 00:34:19,540 When others are frying, these ants have solar tech 309 00:34:19,540 --> 00:34:22,740 to stop them from overheating... 310 00:34:27,140 --> 00:34:30,220 ..special glassy hairs and shining bodies 311 00:34:30,220 --> 00:34:33,260 that reflect the sun's lethal rays. 312 00:34:35,660 --> 00:34:38,140 It buys them precious time. 313 00:34:45,700 --> 00:34:48,780 To get their prize back as quickly as possible 314 00:34:48,780 --> 00:34:52,380 to their underground den demands teamwork. 315 00:34:59,700 --> 00:35:02,940 But shelter is a long way away. 316 00:35:05,180 --> 00:35:08,180 Any technique will do. 317 00:35:08,180 --> 00:35:10,580 The push and slide. 318 00:35:13,540 --> 00:35:15,540 The spin. 319 00:35:18,380 --> 00:35:21,100 Even dune surfing. 320 00:35:31,980 --> 00:35:35,220 The nest is still 70 metres away. 321 00:35:45,780 --> 00:35:49,020 Some are already collapsing in the heat. 322 00:35:51,300 --> 00:35:54,740 Reinforcements are needed urgently. 323 00:35:56,860 --> 00:36:01,260 Now the heat whips up violent gusts of hot desert air. 324 00:36:04,500 --> 00:36:07,020 For an ant, these are hurricanes. 325 00:36:12,620 --> 00:36:14,860 WIND HOWLS 326 00:36:27,620 --> 00:36:31,340 They must get their prize underground as soon as possible, 327 00:36:31,340 --> 00:36:35,980 and blown sand has blocked the entrance to their den. 328 00:36:35,980 --> 00:36:39,220 Any longer out here and they will be toast. 329 00:36:45,460 --> 00:36:48,220 One final effort. 330 00:37:01,780 --> 00:37:04,620 The last of the team race home. 331 00:37:08,260 --> 00:37:11,620 Shade, at last. 332 00:37:19,260 --> 00:37:22,820 Much of the land on our planet could become as scorched 333 00:37:22,820 --> 00:37:26,420 and lifeless as this if we allow our activities 334 00:37:26,420 --> 00:37:29,420 to continue to change the atmosphere. 335 00:37:33,700 --> 00:37:38,540 The Sahara alone has expanded by an area twice the size of France 336 00:37:38,540 --> 00:37:41,620 in just the last hundred years... 337 00:37:41,620 --> 00:37:44,580 WIND GUSTS 338 00:37:44,580 --> 00:37:50,260 ..part of a global desert invasion that threatens a third of all land. 339 00:37:55,220 --> 00:37:58,420 The sun can certainly be a lethal threat, 340 00:37:58,420 --> 00:38:00,420 but it could also be our saviour. 341 00:38:01,540 --> 00:38:05,100 The solar energy that strikes our planet in just an hour 342 00:38:05,100 --> 00:38:09,460 contains more power than that used by all of humanity 343 00:38:09,460 --> 00:38:12,060 in an entire year. 344 00:38:21,180 --> 00:38:24,700 By October, as the Earth completes its annual journey 345 00:38:24,700 --> 00:38:28,940 around the sun, day lengths in the northern hemisphere 346 00:38:28,940 --> 00:38:31,540 are shortening once again. 347 00:38:35,220 --> 00:38:39,100 The sun's power is diminishing. 348 00:38:39,100 --> 00:38:44,220 Trees are beginning to shut down their solar panels. 349 00:38:44,220 --> 00:38:48,660 The green chlorophyll with which they collected the sun's energy 350 00:38:48,660 --> 00:38:52,260 is broken down chemically and reabsorbed. 351 00:39:00,660 --> 00:39:05,060 And the forests turn from emerald to gold. 352 00:39:07,140 --> 00:39:09,140 It's autumn. 353 00:39:12,580 --> 00:39:17,780 Once again, the living world away from the tropics is transformed. 354 00:39:20,500 --> 00:39:23,580 Plants stop growing 355 00:39:23,580 --> 00:39:27,780 and many animals begin to prepare for tough times ahead. 356 00:39:36,740 --> 00:39:39,860 The forests of central China... 357 00:39:41,660 --> 00:39:45,580 ..home to the golden snub-nosed monkey. 358 00:39:49,660 --> 00:39:53,180 They will not survive the fast-approaching winter 359 00:39:53,180 --> 00:39:56,660 unless they stock up on calorie-rich food. 360 00:39:59,220 --> 00:40:05,220 Top of their autumn menu - pine cones, 361 00:40:05,220 --> 00:40:09,540 They grew during the summer sunlight and are rich in fats. 362 00:40:14,340 --> 00:40:16,500 Few are now left, 363 00:40:16,500 --> 00:40:19,340 and time to gather them is running out. 364 00:40:25,940 --> 00:40:29,060 Dominant males patrol the troop, 365 00:40:29,060 --> 00:40:31,620 making sure they get the pick of the crop. 366 00:40:31,620 --> 00:40:34,500 MONKEYS SCREECH 367 00:40:34,500 --> 00:40:37,140 As the number of pine cones dwindles, 368 00:40:37,140 --> 00:40:40,140 tensions between rival families increase. 369 00:40:40,140 --> 00:40:43,420 AGGRESSIVE SCREECHING 370 00:40:48,300 --> 00:40:54,140 Mere threats between two males may not be enough to settle disputes. 371 00:40:58,580 --> 00:41:00,940 MONKEYS SCREECH 372 00:41:00,940 --> 00:41:03,620 Conflict is in the air. 373 00:41:04,980 --> 00:41:07,100 There's going to be a fight. 374 00:41:37,140 --> 00:41:39,540 MONKEY SCREECHES 375 00:41:39,540 --> 00:41:41,820 Vital food is at stake, 376 00:41:41,820 --> 00:41:44,540 so every pine cone is worth fighting for. 377 00:42:08,300 --> 00:42:09,380 MONKEY SCREECHES 378 00:42:10,780 --> 00:42:15,820 The victor and his family enjoy the spoils of war. 379 00:42:19,300 --> 00:42:23,180 The losers get no more than a few dead leaves 380 00:42:23,180 --> 00:42:27,220 and will have fewer energy reserves for the coming winter. 381 00:42:31,460 --> 00:42:33,900 The sun's power dims. 382 00:42:35,300 --> 00:42:37,660 Temperatures drop. 383 00:42:42,740 --> 00:42:45,300 Everything slows down. 384 00:42:47,980 --> 00:42:51,980 Ahead lies months of crippling cold. 385 00:42:51,980 --> 00:42:53,660 MONKEY WHINES 386 00:43:10,860 --> 00:43:14,820 Most of the life on Earth away from the tropics 387 00:43:14,820 --> 00:43:19,020 has managed to adapt to the changing seasons, 388 00:43:19,020 --> 00:43:21,860 but there are some creatures that have found a way 389 00:43:21,860 --> 00:43:25,060 to avoid the cold of winter altogether. 390 00:43:26,620 --> 00:43:29,540 Snares Island, New Zealand, 391 00:43:29,540 --> 00:43:31,980 deep in the southern hemisphere. 392 00:43:31,980 --> 00:43:34,100 CAWING 393 00:43:34,100 --> 00:43:38,060 Here, sooty shearwaters have been nesting throughout the long summer 394 00:43:38,060 --> 00:43:40,860 and gorging themselves on fish. 395 00:43:42,380 --> 00:43:46,580 As a result, they've piled on quite a few pounds. 396 00:43:49,100 --> 00:43:53,340 But the sun is now fading, and the southern winter is approaching. 397 00:43:54,540 --> 00:43:57,620 No time to hang around. 398 00:43:57,620 --> 00:43:59,700 SHEARWATERS CAW 399 00:44:06,060 --> 00:44:08,140 When you're a touch tubby, 400 00:44:08,140 --> 00:44:10,780 launching into the air... 401 00:44:10,780 --> 00:44:12,620 ..is a leap of faith. 402 00:44:15,700 --> 00:44:19,620 They won't see land again for four weeks. 403 00:44:24,300 --> 00:44:27,700 Setting off across the Pacific, they're starting on 404 00:44:27,700 --> 00:44:32,100 one of the longest journeys made by any living thing. 405 00:44:34,180 --> 00:44:38,860 Their aim - to avoid the consequences of the Earth's tilt 406 00:44:38,860 --> 00:44:43,100 and follow the sun's warmth as it dwindles in the south 407 00:44:43,100 --> 00:44:45,620 and increases in the north. 408 00:44:57,660 --> 00:45:01,540 For those who survive the 10,000-mile marathon, 409 00:45:01,540 --> 00:45:04,220 there will be a great prize. 410 00:45:08,620 --> 00:45:12,540 The reward for travelling from one end of the planet to the other 411 00:45:12,540 --> 00:45:16,180 is long summer days the year round. 412 00:45:18,900 --> 00:45:21,260 This is their destination... 413 00:45:22,940 --> 00:45:25,580 ..Alaska's Aleutian Islands. 414 00:45:29,220 --> 00:45:32,860 While the south of our planet is slipping into autumn... 415 00:45:34,460 --> 00:45:37,380 ..here, summer is just beginning. 416 00:45:47,500 --> 00:45:52,540 Below the waves, vast clouds of plankton are blooming. 417 00:45:53,780 --> 00:45:56,460 Triggered by the sunlight, 418 00:45:56,460 --> 00:45:59,100 these tiny marine organisms 419 00:45:59,100 --> 00:46:02,100 are food for crustaceans - krill. 420 00:46:04,980 --> 00:46:07,860 This is the sun-fuelled bounty 421 00:46:07,860 --> 00:46:10,620 for which the shearwaters have crossed the planet. 422 00:46:17,340 --> 00:46:19,420 By cheating the tilt, 423 00:46:19,420 --> 00:46:23,060 they're able to enjoy the riches of summer the year round. 424 00:46:30,340 --> 00:46:35,020 But shearwaters are not the only ones to visit the warming seas. 425 00:46:36,820 --> 00:46:40,100 WHALES CALL 426 00:46:41,380 --> 00:46:43,540 Humpback whales. 427 00:46:45,700 --> 00:46:49,180 They've been breeding in the tropics... 428 00:46:49,180 --> 00:46:51,980 ..and haven't fed for six months. 429 00:47:02,500 --> 00:47:07,700 Up to 6,000 whales are now heading for these islands - 430 00:47:07,700 --> 00:47:13,220 the only place where they can find food in the quantities they need. 431 00:47:17,860 --> 00:47:22,540 The shearwaters begin to dive into a huge shoal of krill. 432 00:47:28,220 --> 00:47:30,860 The humpbacks attack from below. 433 00:47:38,420 --> 00:47:42,500 Each year, a million shearwaters join the whales 434 00:47:42,500 --> 00:47:45,420 in these dramatic feeding frenzies. 435 00:47:58,740 --> 00:48:02,740 It's one of the greatest gatherings of life on Earth. 436 00:48:04,060 --> 00:48:08,780 And it only happens because some whales and some birds 437 00:48:08,780 --> 00:48:12,980 have found a way to live in a summer that never ends. 438 00:48:32,820 --> 00:48:36,140 Rolf Steinmann has wanted to be a wildlife cameraman 439 00:48:36,140 --> 00:48:42,020 since he was a child, even if he has to remind himself from time to time. 440 00:48:42,020 --> 00:48:46,420 I'm a lucky cameraman. 441 00:48:46,420 --> 00:48:48,700 I'm a lucky cameraman... 442 00:48:48,700 --> 00:48:52,860 To those who've worked with Rolf, his love of the wild is legendary. 443 00:48:52,860 --> 00:48:55,020 You know, if he's not on location, he's at home watching 444 00:48:55,020 --> 00:48:57,420 every other wildlife documentary that's ever been made. 445 00:48:57,420 --> 00:49:01,340 I think Rolf is motivated by the beauty in the world. 446 00:49:01,340 --> 00:49:03,540 I think he really has this pure heart. 447 00:49:03,540 --> 00:49:06,460 Rolf alone with nature is Rolf at his best. 448 00:49:06,460 --> 00:49:09,820 Rolf is a man obsessed. 449 00:49:09,820 --> 00:49:12,900 The opportunity to be the first to film arctic wolves 450 00:49:12,900 --> 00:49:16,540 in the polar night is Rolf's dream of a lifetime. 451 00:49:17,940 --> 00:49:21,620 We have a lot of luggage. This is a major expedition. 452 00:49:21,620 --> 00:49:25,300 And there's one piece of luggage that is very, 453 00:49:25,300 --> 00:49:27,660 very special to me, and it's... 454 00:49:27,660 --> 00:49:30,580 It's actually this book by Jim Brandenburg. 455 00:49:30,580 --> 00:49:32,580 It's 30 years old, it's from the '80s. 456 00:49:32,580 --> 00:49:35,140 And when I saw this book the first time, 457 00:49:35,140 --> 00:49:38,820 it really triggered a dream to become a wildlife cameraman. 458 00:49:38,820 --> 00:49:41,060 And this was the shot. 459 00:49:41,060 --> 00:49:42,940 It's unmatched to this day. 460 00:49:42,940 --> 00:49:46,180 When I saw it, I just wanted to experience it myself. 461 00:49:46,180 --> 00:49:50,540 To go to Ellesmere now and to film wolves is... 462 00:49:50,540 --> 00:49:53,300 ..is my biggest dream coming true. 463 00:49:53,300 --> 00:49:57,140 If I'm honest, I'm not just excited about the shoot, 464 00:49:57,140 --> 00:49:59,500 I'm also a little bit anxious. 465 00:49:59,500 --> 00:50:02,740 I haven't worked in -50 degrees, 466 00:50:02,740 --> 00:50:07,100 and actually trying to find wolves in darkness, in the polar night, 467 00:50:07,100 --> 00:50:11,340 is something that has not even been tried by anyone. 468 00:50:18,100 --> 00:50:24,100 Ellesmere Island lies just 500 miles from the North Pole. 469 00:50:24,100 --> 00:50:27,980 In the winter, the sun doesn't rise for four months. 470 00:50:29,060 --> 00:50:34,260 The temperature regularly drops to -50 degrees... 471 00:50:34,260 --> 00:50:37,820 ..making it one of the coldest places on Earth. 472 00:50:39,500 --> 00:50:41,460 It's such an unreal place. 473 00:50:41,460 --> 00:50:44,540 It's like a...like a frozen dream. 474 00:50:46,500 --> 00:50:49,340 There's so much space. 475 00:50:49,340 --> 00:50:51,900 It's really like a different planet. 476 00:50:54,420 --> 00:50:57,660 The wolves here can range for thousands of miles 477 00:50:57,660 --> 00:50:59,860 across the frozen landscape. 478 00:51:01,380 --> 00:51:04,540 If you look at that landscape, 479 00:51:04,540 --> 00:51:06,820 how vast it is, 480 00:51:06,820 --> 00:51:10,060 you can imagine how hard it is to find the wolves, 481 00:51:10,060 --> 00:51:13,100 a white animal in a white landscape. 482 00:51:15,940 --> 00:51:19,180 One wolf has a radio collar, 483 00:51:19,180 --> 00:51:25,100 but this kind of telemetry only gives a rough direction to explore. 484 00:51:25,100 --> 00:51:27,540 The fjord is just to the south, so I think the best plan 485 00:51:27,540 --> 00:51:30,860 is cut across on the ice and see if we can find a way up. 486 00:51:30,860 --> 00:51:34,820 The team race towards the wolf's last broadcast position 487 00:51:34,820 --> 00:51:36,460 and get lucky. 488 00:51:36,460 --> 00:51:38,900 They find the whole pack, 489 00:51:38,900 --> 00:51:41,780 and something never seen before. 490 00:51:43,340 --> 00:51:46,540 This is so incredible. HE LAUGHS 491 00:51:46,540 --> 00:51:49,300 A herd of hundreds of arctic hares 492 00:51:49,300 --> 00:51:52,500 are under attack from Rolf's white wolves. 493 00:51:54,660 --> 00:51:57,580 HE CHUCKLES Wow. 494 00:51:57,580 --> 00:51:59,620 We found our... 495 00:51:59,620 --> 00:52:02,300 ..our pack of seven wolves, 496 00:52:02,300 --> 00:52:05,260 in their full beauty, which is amazing. 497 00:52:06,940 --> 00:52:11,500 Filming the new behaviour ramps up the pressure on Rolf. 498 00:52:11,500 --> 00:52:15,420 Oh, God, the situation is just right in the wrong spot. 499 00:52:16,900 --> 00:52:21,340 Rolf is well known for his self-criticism. 500 00:52:21,340 --> 00:52:22,900 He's a perfectionist. 501 00:52:22,900 --> 00:52:26,420 You know, he wants that image to be absolutely perfect. 502 00:52:28,260 --> 00:52:31,700 You're amazing, but I'm stupid, unfortunately. 503 00:52:35,660 --> 00:52:40,860 A day later, the wolves disappear out of range of the telemetry. 504 00:52:40,860 --> 00:52:44,340 It said they were here, but now they aren't here 505 00:52:44,340 --> 00:52:47,380 and we don't get any signal from the telemetry. 506 00:52:47,380 --> 00:52:52,460 So, now I think we realise how hard it will be to find the wolves 507 00:52:52,460 --> 00:52:54,700 if we don't just run into them. 508 00:52:55,980 --> 00:52:58,820 With no wolves to film, Rolf is determined 509 00:52:58,820 --> 00:53:02,180 to capture the beauty of the landscape with a drone. 510 00:53:12,380 --> 00:53:14,620 We just can't get the thing in the air. 511 00:53:14,620 --> 00:53:18,940 Um, the motors, they've physically frozen solid. 512 00:53:18,940 --> 00:53:22,300 And the drone's not the only thing that's freezing. 513 00:53:22,300 --> 00:53:25,940 Look what I just found under my mask. 514 00:53:25,940 --> 00:53:27,340 ROLF LAUGHS 515 00:53:31,620 --> 00:53:34,260 THEY LAUGH 516 00:53:44,860 --> 00:53:49,820 A plan to warm up the drone with a hairdryer and a duffel bag 517 00:53:49,820 --> 00:53:54,180 could mean that the world record for the coldest flight is still on. 518 00:53:55,980 --> 00:53:57,780 Success! 519 00:54:04,580 --> 00:54:09,300 But the cold soon takes its toll on Jesse, the drone operator. 520 00:54:09,300 --> 00:54:13,060 Argh! I'm sorry, I can't feel my hands. 521 00:54:13,060 --> 00:54:16,740 I think we have to drift to the right a little bit more. 522 00:54:16,740 --> 00:54:20,380 When you're on a shoot with Rolf, he'll just keep going 523 00:54:20,380 --> 00:54:22,900 and going and going. 524 00:54:22,900 --> 00:54:24,900 We can fly towards the big mountain. 525 00:54:24,900 --> 00:54:28,100 I can get the... Argh! ..the big mountain, you know... 526 00:54:28,100 --> 00:54:29,940 Yeah. ..like, more centred. 527 00:54:29,940 --> 00:54:32,740 Argh! My hands! 528 00:54:32,740 --> 00:54:36,660 Come on, it's coming, it's coming. You just fly straight, Jesse. 529 00:54:36,660 --> 00:54:39,180 But I'm losing my sensation in my hands, Rolf. 530 00:54:39,180 --> 00:54:41,500 Yeah, let's hit roll on it before we die... Let's record. 531 00:54:41,500 --> 00:54:43,180 Come on, do it. 532 00:54:45,380 --> 00:54:49,060 This feels like a totally different planet. It's really crazy. 533 00:54:49,060 --> 00:54:52,940 OK, and I think now we could do a forward view. Yeah. 534 00:54:52,940 --> 00:54:56,100 Argh! Perfect, Jesse. You can go a bit slower. 535 00:54:56,100 --> 00:54:59,020 If you can, go a bit slower. My fingers are hurting. 536 00:55:00,660 --> 00:55:01,900 Argh! 537 00:55:01,900 --> 00:55:03,940 That looks really cool! 538 00:55:03,940 --> 00:55:06,060 It's incredible. 539 00:55:09,980 --> 00:55:12,620 With no sighting of the wolves in weeks, 540 00:55:12,620 --> 00:55:16,020 the team decide to follow their prey instead. 541 00:55:17,460 --> 00:55:20,100 Muskoxen. 542 00:55:20,100 --> 00:55:21,620 And the tactic pays off. 543 00:55:22,740 --> 00:55:25,580 The herd is being shadowed by the wolves. 544 00:55:25,580 --> 00:55:28,220 MUSKOX GRUNT 545 00:55:31,380 --> 00:55:34,100 They are very close to a herd of muskoxen there, 546 00:55:34,100 --> 00:55:35,580 and something might happen. 547 00:55:40,220 --> 00:55:44,420 Rolf is in the perfect spot to capture the first arctic wolf hunt 548 00:55:44,420 --> 00:55:47,500 ever filmed in the polar night. 549 00:55:53,220 --> 00:55:55,260 WOLVES WHINE 550 00:55:55,260 --> 00:55:59,100 God, there was some good stuff, I think, if I got it in focus. 551 00:56:00,940 --> 00:56:06,660 With the shots in the can, there is a magical experience for Rolf... 552 00:56:06,660 --> 00:56:10,060 ..one he's dreamed of since he was a child. 553 00:56:16,460 --> 00:56:18,980 It doesn't get better than this. 554 00:56:21,860 --> 00:56:24,060 WOLVES WHINE 555 00:56:24,060 --> 00:56:27,140 Oh, my God. This is an absolutely... 556 00:56:27,140 --> 00:56:29,060 ..dream of a lifetime. 557 00:56:32,620 --> 00:56:37,740 Honestly, you are the most beautiful living being I've ever seen. 558 00:56:37,740 --> 00:56:39,300 Incredible. 559 00:56:49,060 --> 00:56:50,740 Next time... 560 00:56:50,740 --> 00:56:52,100 ..weather. 561 00:56:55,380 --> 00:56:59,820 This powerful force carries vital freshwater around the globe. 562 00:57:02,220 --> 00:57:07,740 And all life on land is perfectly in tune with its annual rhythms. 563 00:57:14,660 --> 00:57:17,900 The Open University has produced a free poster 564 00:57:17,900 --> 00:57:20,340 exploring our perfect planet. 565 00:57:20,340 --> 00:57:25,620 To order, please call 0300 303 0901. 566 00:57:25,620 --> 00:57:30,340 Or go to bbc.co.uk/perfectplanet 567 00:57:30,340 --> 00:57:33,300 and follow the links to the Open University.