1 00:00:20,960 --> 00:00:25,640 STEPHEN FRY: 'It's hard to describe how still it is 2 00:00:25,640 --> 00:00:29,960 'on a glacier surrounded by a fresh blanket of snow.' 3 00:00:32,960 --> 00:00:34,960 Which makes the fact that I'm moving 4 00:00:34,960 --> 00:00:37,960 at 490,000mph 5 00:00:37,960 --> 00:00:39,960 all the more extraordinary. 6 00:00:39,960 --> 00:00:42,960 But I, like everyone, like you, 7 00:00:42,960 --> 00:00:47,960 am hurtling through space on our annual journey around the sun. 8 00:00:47,960 --> 00:00:50,960 'For the first time, 9 00:00:50,960 --> 00:00:55,160 'this series explores how all life on our planet... 10 00:00:56,960 --> 00:00:59,160 '..is shaped by this orbit. 11 00:01:00,960 --> 00:01:03,960 'How where you are on Earth... 12 00:01:03,960 --> 00:01:06,960 THUNDER CRACKS 13 00:01:06,960 --> 00:01:09,640 '..makes a world of difference. 14 00:01:09,640 --> 00:01:12,960 'And no matter how far apart... 15 00:01:13,960 --> 00:01:17,960 '..how everything is connected. 16 00:01:17,960 --> 00:01:19,960 'Epic weather systems... 17 00:01:21,960 --> 00:01:24,960 '..trigger seasonal spectacles... 18 00:01:25,960 --> 00:01:28,960 '..driving animals to move... 19 00:01:32,960 --> 00:01:34,800 '..to fight... 20 00:01:37,480 --> 00:01:39,960 '..and even to love. 21 00:01:44,800 --> 00:01:48,320 'Filmed across more than 60 locations... 22 00:01:49,960 --> 00:01:53,960 '..we'll see this unique annual journey 23 00:01:53,960 --> 00:01:56,960 'through the eyes of incredible animal families... 24 00:01:58,960 --> 00:02:04,960 '..as they take on everything the seasons can throw at them. 25 00:02:31,960 --> 00:02:34,960 'It's high in the Northern Hemisphere 26 00:02:34,960 --> 00:02:36,960 'where winter hits earliest. 27 00:02:43,960 --> 00:02:45,000 'By late-October, 28 00:02:45,000 --> 00:02:47,960 'most animals have already fled south 29 00:02:47,960 --> 00:02:49,960 'to escape the brutal cold. 30 00:02:54,800 --> 00:02:56,960 'Only the toughest remain. 31 00:03:03,480 --> 00:03:06,960 'For now, this mother and her two-year-old cub 32 00:03:06,960 --> 00:03:09,960 'still have time to play. 33 00:03:22,800 --> 00:03:26,960 'It will be the last winter they spend together. 34 00:03:29,000 --> 00:03:31,960 'Polar bears are solitary animals... 35 00:03:33,960 --> 00:03:37,960 '..and she only has until spring to prepare her cub... 36 00:03:38,960 --> 00:03:40,960 '..for a life alone. 37 00:03:46,800 --> 00:03:49,960 'Since birth, he's followed in her footsteps... 38 00:03:51,960 --> 00:03:55,960 '..and she's had to hunt for both of them. 39 00:04:07,960 --> 00:04:13,480 'The ice in Svalbard's fjords acts as their main hunting platform. 40 00:04:14,960 --> 00:04:18,640 'But right now, it's only just forming... 41 00:04:20,960 --> 00:04:25,960 '..and opportunities are thin on the ground. 42 00:04:28,960 --> 00:04:30,960 'A ringed seal. 43 00:04:34,960 --> 00:04:36,480 'A lifeline. 44 00:04:48,160 --> 00:04:50,960 'The cub knows to stay back. 45 00:05:25,960 --> 00:05:28,960 'Every week without food... 46 00:05:28,960 --> 00:05:32,960 'mother and cub lose a tenth of their weight. 47 00:05:35,960 --> 00:05:37,960 'Tough times lie ahead. 48 00:05:43,960 --> 00:05:46,960 'The seasonal challenges animals face 49 00:05:46,960 --> 00:05:51,960 'are all created by a quirk unique to our planet.' 50 00:05:51,960 --> 00:05:55,960 Our journey around that nuclear reactor 51 00:05:55,960 --> 00:05:59,960 affects almost all life on Earth. 52 00:05:59,960 --> 00:06:02,640 And as we circle it, 53 00:06:02,640 --> 00:06:05,960 we do so on a titled axis. 54 00:06:06,960 --> 00:06:10,480 'It's this that creates the seasons. 55 00:06:10,480 --> 00:06:12,960 'During summer, the Northern Hemisphere 56 00:06:12,960 --> 00:06:14,960 'leans towards the sun. 57 00:06:15,960 --> 00:06:20,960 'But six months later, the north tilts away from the sun... 58 00:06:21,960 --> 00:06:24,960 '..and days become shorter and darker.' 59 00:06:28,960 --> 00:06:32,960 Despite being clad head to foot in specialist winter gear, 60 00:06:32,960 --> 00:06:36,000 I wouldn't survive a night on this hillside. 61 00:06:37,960 --> 00:06:39,960 'Thankfully, I won't have to. 62 00:06:42,960 --> 00:06:45,960 'But this mother and cub must be prepared to face 63 00:06:45,960 --> 00:06:49,960 'some of the toughest conditions on the planet. 64 00:06:51,960 --> 00:06:54,960 'It's the last time they'll see the sun this year. 65 00:07:07,160 --> 00:07:10,320 'Polar winter is here. 66 00:07:12,320 --> 00:07:16,960 'This one night will last for more than a 100 days. 67 00:07:21,480 --> 00:07:25,960 'Somehow, this mother will have to find enough food 68 00:07:25,960 --> 00:07:30,160 'to see them through the dark times ahead. 69 00:07:35,960 --> 00:07:38,960 'When it's winter in the Northern Hemisphere, 70 00:07:38,960 --> 00:07:41,960 'at the other end of the Earth, it's summer. 71 00:07:42,960 --> 00:07:45,960 'The Southern Hemisphere is tilted towards the sun... 72 00:07:47,960 --> 00:07:52,960 '..bathed in its warmth and light, and teeming with life. 73 00:07:58,960 --> 00:08:01,640 'After a two-week fishing trip, 74 00:08:01,640 --> 00:08:03,960 'these king penguins are heading home 75 00:08:03,960 --> 00:08:06,960 'to a tiny speck of land, 76 00:08:06,960 --> 00:08:10,960 '1,000 miles south of the African continent. 77 00:08:12,320 --> 00:08:15,960 'Some have swum up to 4,000 miles 78 00:08:15,960 --> 00:08:17,960 'in search of food. 79 00:08:46,960 --> 00:08:48,960 'They're home. 80 00:08:49,960 --> 00:08:52,960 'But the moment they set foot on land, 81 00:08:52,960 --> 00:08:55,160 'all that grace disappears. 82 00:09:06,960 --> 00:09:09,960 'Still, he needs to keep moving. 83 00:09:10,960 --> 00:09:12,800 'After so long at sea, 84 00:09:12,800 --> 00:09:15,960 'he's desperate to reunite with his mate. 85 00:09:17,960 --> 00:09:22,000 'But a million other penguins have had the same idea. 86 00:09:23,480 --> 00:09:24,960 'Oh, my! 87 00:09:24,960 --> 00:09:27,960 'This might take some time. 88 00:09:29,160 --> 00:09:31,640 'It's December, 89 00:09:31,640 --> 00:09:34,960 'and in the Southern Hemisphere, that means summer. 90 00:09:34,960 --> 00:09:38,960 'A tenth of all the king penguins on Earth 91 00:09:38,960 --> 00:09:42,160 'have come to Marion Island to breed. 92 00:09:43,960 --> 00:09:47,160 'And this male needs to find his mate in the crowd. 93 00:09:48,640 --> 00:09:50,960 It may seem an impossible task, 94 00:09:50,960 --> 00:09:53,960 'but king penguins have an extraordinary ability 95 00:09:53,960 --> 00:09:55,960 'to locate one another. 96 00:09:55,960 --> 00:10:00,960 'He can filter the cacophony of half a million birds 97 00:10:00,960 --> 00:10:03,960 'to isolate her call. 98 00:10:10,960 --> 00:10:14,960 It's known as the cocktail party effect. 99 00:10:14,960 --> 00:10:18,960 'Rather apt for a bird in a dinner suit. 100 00:10:20,640 --> 00:10:22,960 'Hearing her is one thing. 101 00:10:22,960 --> 00:10:25,960 'Getting to her another. 102 00:10:27,960 --> 00:10:31,960 'Every corner of the colony is contested. 103 00:10:34,960 --> 00:10:38,320 'And penguins were enforcing social distancing 104 00:10:38,320 --> 00:10:40,160 'long before we'd heard of it. 105 00:11:20,000 --> 00:11:23,480 'Finally, reunited. 106 00:11:23,480 --> 00:11:25,960 HOOTING 107 00:11:25,960 --> 00:11:28,960 'She's waited more than two weeks, 108 00:11:28,960 --> 00:11:35,960 'going without food or water, to guard their newly-laid egg. 109 00:11:39,960 --> 00:11:42,960 'Now it's his turn to care for it. 110 00:11:49,960 --> 00:11:55,800 'This egg is the pair's only chance to raise a chick this year. 111 00:11:56,960 --> 00:12:01,960 'Just getting it to hatch will take incredible devotion. 112 00:12:05,960 --> 00:12:08,960 'Taking turns to sit on the egg 113 00:12:08,960 --> 00:12:12,640 'while the other feeds in the summer seas. 114 00:12:14,960 --> 00:12:16,960 'This far south, 115 00:12:16,960 --> 00:12:20,000 'the sun's rays hit Marion Island at an angle. 116 00:12:21,960 --> 00:12:23,960 'But further north, 117 00:12:23,960 --> 00:12:27,960 'the Earth's tilt means that in Southern Africa, 118 00:12:27,960 --> 00:12:33,960 'along the Tropic of Capricorn, the sun is directly overhead. 119 00:12:33,960 --> 00:12:37,320 'Here, its energy is at its most concentrated, 120 00:12:37,320 --> 00:12:40,320 'super-heating the land, 121 00:12:40,320 --> 00:12:42,960 'driving cloud formation 122 00:12:42,960 --> 00:12:46,960 'and bringing the rains to Botswana.' 123 00:12:46,960 --> 00:12:48,960 THUNDER RUMBLES 124 00:12:58,960 --> 00:13:02,960 'There couldn't be a more perfect time to be born. 125 00:13:04,960 --> 00:13:07,960 'Much of an elephant's existence 126 00:13:07,960 --> 00:13:10,960 'revolves around the search for water. 127 00:13:11,960 --> 00:13:15,960 'During the rainy season in the Southern Hemisphere, 128 00:13:15,960 --> 00:13:21,480 'there's so much of it that life is about as easy as it gets. 129 00:13:27,960 --> 00:13:30,960 'But it doesn't stay like this for long. 130 00:13:34,000 --> 00:13:37,960 This one-month-old baby elephant's first year 131 00:13:37,960 --> 00:13:40,960 'will be the most challenging of his whole life. 132 00:13:51,960 --> 00:13:55,960 'The savannahs are at their lushest, 133 00:13:55,960 --> 00:13:57,960 'the rivers at their fullest, 134 00:13:57,960 --> 00:14:02,960 'and there's a baby boom in Botswana. 135 00:14:11,960 --> 00:14:15,960 'There's a world of new life to discover. 136 00:14:22,960 --> 00:14:26,320 'With refreshment at every turn. 137 00:14:27,960 --> 00:14:29,960 'Just as well. 138 00:14:30,960 --> 00:14:35,960 'An adult elephant needs over 200 litres a day. 139 00:14:45,960 --> 00:14:49,800 'But the baby gets all he needs from milk. 140 00:14:49,800 --> 00:14:52,960 'So a trip to the river means it's time to play. 141 00:15:03,960 --> 00:15:06,960 'Life may seem idyllic now, 142 00:15:06,960 --> 00:15:10,960 'but danger is never far away. 143 00:15:15,960 --> 00:15:17,960 'There are lion prides 144 00:15:17,960 --> 00:15:20,960 'that specialise in taking down elephants. 145 00:15:20,960 --> 00:15:25,000 'And it's the smallest that are the most vulnerable. 146 00:15:52,960 --> 00:15:54,960 'But during the wet season, 147 00:15:54,960 --> 00:15:58,960 'there's plenty of easier prey for the lions to chase. 148 00:16:00,960 --> 00:16:07,960 'Botswana has distinct periods of summer rain and winter sun. 149 00:16:07,960 --> 00:16:09,960 'But along the equator, 150 00:16:09,960 --> 00:16:12,960 'the seasons, as we know them, all but disappear. 151 00:16:14,480 --> 00:16:18,800 'Consistent sunlight all year round 152 00:16:18,800 --> 00:16:21,960 'creates the ideal conditions 153 00:16:21,960 --> 00:16:24,960 'for tropical rainforests to thrive. 154 00:16:26,960 --> 00:16:29,960 'Animals living here don't waste precious energy 155 00:16:29,960 --> 00:16:34,960 'surviving seasonal extremes, or migrating to escape them. 156 00:16:35,960 --> 00:16:39,960 'Instead, they can put it into something 157 00:16:39,960 --> 00:16:42,960 'a little bit more... fabulous. 158 00:16:43,960 --> 00:16:48,160 'From the weird... to the wonderfully colourful. 159 00:16:52,960 --> 00:16:56,960 'In the jungles of Papua New Guinea and Northern Australia, 160 00:16:56,960 --> 00:17:00,960 'there are a few who focus on more artistic pursuits. 161 00:17:02,960 --> 00:17:05,960 'He may seem a little drab 162 00:17:05,960 --> 00:17:07,960 'compared to other birds of paradise... 163 00:17:08,960 --> 00:17:12,960 '..but he's called a magnificent riflebird 164 00:17:12,960 --> 00:17:14,480 'for a reason. 165 00:17:16,960 --> 00:17:22,160 'He's dedicated his entire life to the art of seduction. 166 00:17:25,640 --> 00:17:29,960 'But to really shine, he needs a partner.' 167 00:17:30,960 --> 00:17:32,960 HE WHISTLES 168 00:17:34,960 --> 00:17:36,960 HE WHISTLES 169 00:17:37,960 --> 00:17:39,960 HE WHISTLES 170 00:17:42,320 --> 00:17:45,960 'Ah! The first audience of the day. 171 00:17:48,960 --> 00:17:52,960 'And this branch, his personal stage 172 00:17:52,960 --> 00:17:57,960 'for a routine he's been perfecting for years. 173 00:17:58,960 --> 00:18:02,320 'It's rarely been seen, let alone filmed. 174 00:18:20,480 --> 00:18:22,960 'With special wing feathers, 175 00:18:22,960 --> 00:18:25,800 'he puts on a shape-shifting display. 176 00:18:28,960 --> 00:18:32,960 'But not every riflebird is what they seem. 177 00:18:35,960 --> 00:18:38,960 'And that's no she. 178 00:18:44,160 --> 00:18:47,960 'Juvenile males look and act like females 179 00:18:47,960 --> 00:18:50,640 'to cheat a front-row seat 180 00:18:50,640 --> 00:18:52,960 'and learn from the best. 181 00:18:54,160 --> 00:18:58,960 'It can take five years of study to master this dance. 182 00:19:07,320 --> 00:19:10,960 'But once he sees through the charade... 183 00:19:12,160 --> 00:19:16,640 '..he has no moves left to teach 184 00:19:16,640 --> 00:19:19,480 'but the cold shoulder. 185 00:19:23,960 --> 00:19:26,960 'No matter how much his fan looks up to him. 186 00:19:36,800 --> 00:19:41,960 'Here, the tropical sun shines more or less 12 hours a day... 187 00:19:42,960 --> 00:19:44,960 '..all year round. 188 00:19:45,960 --> 00:19:49,960 'But far to the north, in the Arctic... 189 00:19:50,960 --> 00:19:54,960 '..there is nothing but darkness. 190 00:19:59,960 --> 00:20:01,960 'It's the winter solstice. 191 00:20:02,960 --> 00:20:06,800 'The shortest day of the year. 192 00:20:09,960 --> 00:20:11,960 'When the Northern Hemisphere 193 00:20:11,960 --> 00:20:16,320 'is tilted as far away from the sun as it can be. 194 00:20:20,480 --> 00:20:22,000 'From this point onwards... 195 00:20:23,960 --> 00:20:26,960 '..days begin to get longer. 196 00:20:28,800 --> 00:20:32,160 'But this polar bear won't see the sun rise 197 00:20:32,160 --> 00:20:35,160 'for another 56 days. 198 00:20:37,800 --> 00:20:41,160 'If it even survives that long. 199 00:20:50,960 --> 00:20:55,160 'The relentless search for food continues 200 00:20:55,160 --> 00:20:58,480 'for the polar bear mother and cub. 201 00:21:00,960 --> 00:21:04,800 'A reindeer fallen victim to the winter storms 202 00:21:04,800 --> 00:21:06,960 'offers some relief. 203 00:21:06,960 --> 00:21:12,960 'But together, they need more than 170,000 calories a week. 204 00:21:14,960 --> 00:21:18,960 'An adult reindeer provides less than half that. 205 00:21:25,960 --> 00:21:28,960 'If they're ever going to see the sun again, 206 00:21:28,960 --> 00:21:33,160 'she'll need to enforce some portion control. 207 00:21:38,480 --> 00:21:42,160 'While the sun may be long gone from the Arctic, 208 00:21:42,160 --> 00:21:44,960 'its presence isn't forgotten. 209 00:21:48,960 --> 00:21:52,960 'Solar winds engulf our planet. 210 00:21:52,960 --> 00:21:57,960 'And these latitudes bear witness to a display on a planetary scale. 211 00:21:59,160 --> 00:22:01,960 'The northern lights. 212 00:22:02,960 --> 00:22:06,960 'When charged particles collide with Earth's magnetic field 213 00:22:06,960 --> 00:22:09,960 'at millions of miles an hour, 214 00:22:09,960 --> 00:22:13,960 'they release enormous amounts of energy. 215 00:22:39,160 --> 00:22:42,960 'These lights are the only way we ever see 216 00:22:42,960 --> 00:22:45,160 'this invisible magnetic force. 217 00:22:47,960 --> 00:22:50,160 'Yet we are still discovering 218 00:22:50,160 --> 00:22:54,800 'how fundamental it is to life on Earth. 219 00:22:58,960 --> 00:23:03,960 'Recent studies suggest it may even help one animal 220 00:23:03,960 --> 00:23:05,960 'catch its next meal. 221 00:23:10,960 --> 00:23:15,800 'Winter storms have covered this red fox's home 222 00:23:15,800 --> 00:23:19,960 'in a blanket of snow three feet deep... 223 00:23:21,960 --> 00:23:25,960 '..and hidden the rodents it usually hunts. 224 00:23:28,960 --> 00:23:30,960 'For some animals, 225 00:23:30,960 --> 00:23:33,960 'this might be a barrier too great to overcome. 226 00:23:36,960 --> 00:23:40,960 'But a fox is cunning and has excellent hearing. 227 00:24:03,960 --> 00:24:07,960 'It's trial... and error. 228 00:24:23,160 --> 00:24:27,960 'But there is one thing he can do to improve his chances. 229 00:24:29,960 --> 00:24:33,960 'Scientists believe red foxes have a sixth sense 230 00:24:33,960 --> 00:24:38,960 'for the same magnetic force that causes the northern lights. 231 00:24:38,960 --> 00:24:43,960 'And they can use it to triangulate their prey's position. 232 00:24:49,960 --> 00:24:53,960 'Pointing to the north-east, he waits for the sound of his prey 233 00:24:53,960 --> 00:24:56,960 'to cross the angle of the magnetic field. 234 00:24:57,960 --> 00:24:59,960 'The sweet spot. 235 00:25:19,960 --> 00:25:25,320 'Using this technique, his hit rate increases fourfold. 236 00:25:27,960 --> 00:25:30,960 'In January's bitter cold, 237 00:25:30,960 --> 00:25:34,960 'it can make the difference between life and death. 238 00:25:37,480 --> 00:25:40,960 'After weeks with little energy from the sun 239 00:25:40,960 --> 00:25:44,480 'the Northern Hemisphere continues to cool. 240 00:25:57,640 --> 00:26:01,960 'Many animals that migrated south to avoid the cold 241 00:26:01,960 --> 00:26:04,960 'are just arriving at their destinations. 242 00:26:04,960 --> 00:26:10,960 'Where better for a spot of winter sun than the coast of Florida? 243 00:26:15,960 --> 00:26:19,960 'Home to luxury apartments, 244 00:26:19,960 --> 00:26:22,800 'golden sands... 245 00:26:23,960 --> 00:26:27,960 '..and warm tropical waters. 246 00:26:28,960 --> 00:26:32,960 'A favourite not just for America's holiday-makers, 247 00:26:32,960 --> 00:26:35,960 'but blacktip sharks, too. 248 00:26:37,960 --> 00:26:40,960 '12,000 of them. 249 00:26:49,960 --> 00:26:51,960 'Just like everyone else, 250 00:26:51,960 --> 00:26:55,960 'they're making the most of the warm water. 251 00:26:55,960 --> 00:26:59,960 'But there's trouble in paradise. 252 00:27:02,960 --> 00:27:05,960 'Great hammerhead sharks, 253 00:27:05,960 --> 00:27:08,640 'up to six metres long, 254 00:27:08,640 --> 00:27:12,480 'have been waiting all year for this seasonal feast. 255 00:27:16,960 --> 00:27:18,960 'For the blacktips, 256 00:27:18,960 --> 00:27:23,960 'travelling in numbers is far safer 257 00:27:23,960 --> 00:27:25,960 'than being caught out alone. 258 00:27:30,960 --> 00:27:35,960 'Together, they have more chance of spotting danger. 259 00:27:39,960 --> 00:27:42,960 'But with eyes on the sides of its head, 260 00:27:42,960 --> 00:27:46,960 'a hammerhead sees in almost every direction. 261 00:27:51,960 --> 00:27:54,960 'They scan for weakness... 262 00:27:57,960 --> 00:28:00,800 '..constantly testing the school. 263 00:28:11,960 --> 00:28:14,960 'One wrong move... 264 00:28:15,960 --> 00:28:17,960 '..is all it takes. 265 00:28:44,320 --> 00:28:46,960 'Despite the risks, 266 00:28:46,960 --> 00:28:48,960 'the promise of food and warmth 267 00:28:48,960 --> 00:28:52,320 'makes the journey south worthwhile. 268 00:28:56,960 --> 00:29:01,960 'Constant sunlight provides a refuge for animals throughout the tropics. 269 00:29:02,960 --> 00:29:05,960 'But for those that live here year-round, 270 00:29:05,960 --> 00:29:09,160 'there are more pressing matters at hand. 271 00:29:12,480 --> 00:29:14,960 'The magnificent riflebird 272 00:29:14,960 --> 00:29:17,960 'is still looking for love.' 273 00:29:17,960 --> 00:29:21,960 HE WHISTLES 274 00:29:21,960 --> 00:29:25,960 'A female... surely. 275 00:29:30,320 --> 00:29:33,960 'He needs to entice her onto the stage. 276 00:29:38,960 --> 00:29:40,320 'A good start. 277 00:29:43,960 --> 00:29:46,960 'But she holds all the cards. 278 00:29:46,960 --> 00:29:50,960 'She'll only mate with the most impressive male. 279 00:29:51,960 --> 00:29:55,960 'Beauty is in the eye of the beholder. 280 00:29:56,960 --> 00:29:59,160 'Well, behold this!' 281 00:30:01,960 --> 00:30:03,960 FLAMENCO MUSIC PLAYS 282 00:30:31,960 --> 00:30:33,960 'A flutter of the wings 283 00:30:33,960 --> 00:30:36,640 'shows she approves. 284 00:30:41,960 --> 00:30:44,960 'It's time for his signature move.' 285 00:30:44,960 --> 00:30:47,480 FLAMENCO GUITAR MUSIC 286 00:31:08,960 --> 00:31:11,640 'It seems to do the trick. 287 00:31:17,960 --> 00:31:20,000 'And after all that, 288 00:31:20,000 --> 00:31:23,320 'he may never dance for her again. 289 00:31:24,960 --> 00:31:26,960 'Her loss!' 290 00:31:26,960 --> 00:31:27,960 HE WHISTLES 291 00:31:27,960 --> 00:31:30,960 'There are plenty more birds in paradise. 292 00:31:34,960 --> 00:31:38,960 'As our planet continues its journey around the sun, 293 00:31:38,960 --> 00:31:41,960 'the seasons start to turn. 294 00:31:46,960 --> 00:31:49,960 'Over 1,000 miles south of the equator, 295 00:31:49,960 --> 00:31:53,960 'the rainy season will soon end. 296 00:31:56,960 --> 00:31:59,960 'Fewer clouds in the sky 297 00:31:59,960 --> 00:32:03,960 'means less protection from the searing sun. 298 00:32:05,960 --> 00:32:09,960 'So the herd seeks shade in the bush. 299 00:32:20,960 --> 00:32:25,960 'The baby elephant's grown more confident and curious. 300 00:32:36,960 --> 00:32:40,960 'He's still not got the hang of that trunk, though. 301 00:32:45,960 --> 00:32:49,960 'It's one of the most complex organs on Earth. 302 00:32:49,960 --> 00:32:53,960 'Delicate enough to pluck a blade of grass, 303 00:32:53,960 --> 00:32:56,960 'strong enough to lift 250 kilos. 304 00:32:59,480 --> 00:33:02,960 'No wonder it'll take the rest of the year to master. 305 00:33:06,960 --> 00:33:10,960 'At least he has plenty of family to practise with. 306 00:33:22,960 --> 00:33:25,960 'Though his older cousin 307 00:33:25,960 --> 00:33:27,960 'can get a little rough. 308 00:33:38,960 --> 00:33:42,960 'It's good preparation for the future. 309 00:33:42,960 --> 00:33:47,960 'So far, all he's known is an easy life. 310 00:33:49,640 --> 00:33:51,640 'But from this point on, 311 00:33:51,640 --> 00:33:54,960 'his home becomes drier. 312 00:33:58,960 --> 00:34:01,960 'The herd will weaken, 313 00:34:01,960 --> 00:34:04,960 'and the lions are waiting. 314 00:34:15,960 --> 00:34:17,960 'For the rest of the year, 315 00:34:17,960 --> 00:34:21,960 'the matriarch must keep the herd from danger 316 00:34:21,960 --> 00:34:26,480 'and guide them on a relentless search for water, 317 00:34:26,480 --> 00:34:30,960 'as rain becomes a distant memory. 318 00:34:36,800 --> 00:34:39,000 'Summer across the Southern Hemisphere 319 00:34:39,000 --> 00:34:41,800 'is coming to an end. 320 00:34:42,960 --> 00:34:47,960 'After cradling their egg for 55 days... 321 00:34:49,960 --> 00:34:52,960 '..the moment the devoted king penguin parents 322 00:34:52,960 --> 00:34:54,960 'have waited for 323 00:34:54,960 --> 00:34:57,960 'has finally arrived. 324 00:34:57,960 --> 00:35:02,960 'It's time to welcome their chick into the world. 325 00:35:05,960 --> 00:35:10,960 'The egg our king penguin parents have been protecting since December 326 00:35:10,960 --> 00:35:12,960 'has finally hatched. 327 00:35:16,960 --> 00:35:20,640 'It will take the rest of the year to raise her. 328 00:35:20,640 --> 00:35:23,960 'The longest parenthood of any bird. 329 00:35:26,960 --> 00:35:30,960 'Exhausted and unsteady... 330 00:35:31,960 --> 00:35:35,960 '..she's ready for her first meal. 331 00:35:48,960 --> 00:35:52,960 'She needs to build her strength as quickly as she can... 332 00:35:56,960 --> 00:36:01,960 '..if she's to survive the voracious predators... 333 00:36:04,960 --> 00:36:07,960 '..and worsening weather. 334 00:36:10,960 --> 00:36:14,960 'As the Southern Hemisphere tilts away from the sun, 335 00:36:14,960 --> 00:36:18,960 'days will get shorter and tougher. 336 00:36:22,960 --> 00:36:24,960 'But in the north, 337 00:36:24,960 --> 00:36:28,960 'the first signs of spring are fast approaching. 338 00:36:37,960 --> 00:36:41,960 'Warmth floods back into Scandinavia's forests. 339 00:36:44,960 --> 00:36:48,960 'A very welcome change for the resident red squirrels. 340 00:36:50,960 --> 00:36:54,960 'They don't hibernate through winter. 341 00:36:54,960 --> 00:36:55,960 'But on a cold morning, 342 00:36:55,960 --> 00:36:59,480 'he's certainly not opposed to a lie-in...' 343 00:36:59,480 --> 00:37:01,960 KNOCKING 344 00:37:01,960 --> 00:37:03,960 KNOCKING CONTINUES 345 00:37:03,960 --> 00:37:07,960 '..when he can get it.' 346 00:37:07,960 --> 00:37:10,960 KNOCKING CONTINUES 347 00:37:14,480 --> 00:37:16,960 KNOCKING CONTINUES 348 00:37:18,960 --> 00:37:21,320 'They just won't shut up.' 349 00:37:23,960 --> 00:37:25,960 KNOCKING 350 00:37:26,960 --> 00:37:28,480 'Fine! 351 00:37:28,480 --> 00:37:32,960 'Might as well make the most of the longer days, now they're here. 352 00:37:47,800 --> 00:37:49,960 'If he's not sleeping, 353 00:37:49,960 --> 00:37:53,480 'he's thinking about his next meal. 354 00:37:57,000 --> 00:37:59,960 'This early in the year, 355 00:37:59,960 --> 00:38:02,960 'there's not much but lichen and bark. 356 00:38:06,960 --> 00:38:10,960 'And too many fellow foragers 357 00:38:10,960 --> 00:38:12,960 'to contend with. 358 00:38:14,960 --> 00:38:17,960 'Including other reds. 359 00:38:17,960 --> 00:38:22,160 'Thankfully, he's, well, squirreled away 360 00:38:22,160 --> 00:38:24,960 'his own secret stash. 361 00:38:26,320 --> 00:38:29,320 'In autumn, when the trees were bursting with nuts, 362 00:38:29,320 --> 00:38:34,960 'he hid almost 3,000 across the forest. 363 00:38:35,960 --> 00:38:38,960 'He thought about his nuts so much, 364 00:38:38,960 --> 00:38:41,960 'his brain had to grow to cope. 365 00:38:43,960 --> 00:38:47,960 'A squirrel's hippocampus expands by 15% 366 00:38:47,960 --> 00:38:50,960 'just to remember where it cached them. 367 00:38:59,960 --> 00:39:01,960 'Yes! 368 00:39:10,480 --> 00:39:12,960 'Many of the other squirrels' stockpiles 369 00:39:12,960 --> 00:39:15,960 'are empty this late in winter, 370 00:39:15,960 --> 00:39:19,960 'so they're on the lookout for an easy meal. 371 00:39:29,960 --> 00:39:34,960 'Packed with protein and rich in fats... 372 00:39:36,960 --> 00:39:40,960 '..these cheats will do whatever they can 373 00:39:40,960 --> 00:39:43,800 'to get their hands 374 00:39:43,800 --> 00:39:45,960 'on his nuts. 375 00:40:50,960 --> 00:40:52,960 'He'll have to keep defending 376 00:40:52,960 --> 00:40:56,160 'his hard-earned stash a little longer. 377 00:41:03,960 --> 00:41:06,640 'As winter comes to an end... 378 00:41:07,960 --> 00:41:12,000 '..more light falls across the Northern Hemisphere. 379 00:41:12,000 --> 00:41:14,960 'Each day, like a tide, 380 00:41:14,960 --> 00:41:17,480 'the sun's life-giving rays 381 00:41:17,480 --> 00:41:21,960 'creep further and further into the Arctic. 382 00:41:24,640 --> 00:41:26,960 'Until, finally... 383 00:41:28,640 --> 00:41:31,000 '..after a 112 days... 384 00:41:33,320 --> 00:41:38,960 '..the sun rises in Svalbard once more. 385 00:42:06,640 --> 00:42:11,800 'The polar bear mother has made it through the long winter. 386 00:42:16,160 --> 00:42:19,960 'And despite all its challenges... 387 00:42:22,960 --> 00:42:25,000 '..so has her cub. 388 00:42:35,960 --> 00:42:37,960 'They say raising a child 389 00:42:37,960 --> 00:42:40,960 'is one of the hardest things you can do in life. 390 00:42:42,800 --> 00:42:44,480 'Letting them go... 391 00:42:45,960 --> 00:42:47,960 '..is even harder. 392 00:42:50,160 --> 00:42:53,960 'She must push him away 393 00:42:53,960 --> 00:42:56,960 'for his own good. 394 00:43:12,800 --> 00:43:15,960 'She's done all she can. 395 00:43:26,960 --> 00:43:28,960 'In his whole life, 396 00:43:28,960 --> 00:43:32,000 'he's never spent a day on his own. 397 00:43:35,960 --> 00:43:40,800 'Now, like all male polar bears, 398 00:43:40,800 --> 00:43:43,960 'apart from the briefest of moments, 399 00:43:43,960 --> 00:43:48,960 'he could roam this frozen wilderness alone 400 00:43:48,960 --> 00:43:51,960 'for another 20 years. 401 00:43:56,960 --> 00:44:00,960 'If he remembers what his mother taught him, 402 00:44:00,960 --> 00:44:02,960 'he might just survive. 403 00:44:06,960 --> 00:44:12,960 'Soon, the sun will hang in the sky 24 hours a day, 404 00:44:12,960 --> 00:44:17,960 'slowly melting away this frozen world 405 00:44:17,960 --> 00:44:21,480 'with its unfathomable power. 406 00:44:22,960 --> 00:44:25,480 'In just one second, 407 00:44:25,480 --> 00:44:30,960 'our sun releases more energy than all mankind has used 408 00:44:30,960 --> 00:44:32,960 'since the beginning of time.' 409 00:44:33,960 --> 00:44:36,320 Just let that sink in. 410 00:44:36,320 --> 00:44:40,960 From now on, it's going to beat down on our northern pole 411 00:44:40,960 --> 00:44:44,960 for just a few extra minutes each day. 412 00:44:45,960 --> 00:44:49,960 Unsurprisingly, the effects are immense. 413 00:44:49,960 --> 00:44:54,960 Even now, its warming touch is changing these icy valleys. 414 00:44:56,480 --> 00:45:00,960 And as the Northern Hemisphere leans once more towards the sun, 415 00:45:00,960 --> 00:45:03,960 great change will sweep the globe. 416 00:45:03,960 --> 00:45:05,960 Spring is on the way, 417 00:45:05,960 --> 00:45:07,960 bringing with it new beginnings 418 00:45:07,960 --> 00:45:09,960 and great hardship 419 00:45:09,960 --> 00:45:13,960 for those who call this planet home. 420 00:45:30,640 --> 00:45:33,480 Subtitles by accessibility@itv.com