1 00:00:35,520 --> 00:00:39,200 David Attenborough: In winter, at the top of the planet 2 00:00:39,320 --> 00:00:41,960 lies an icy wilderness... 3 00:00:43,040 --> 00:00:46,600 Not of land but of frozen water. 4 00:00:48,120 --> 00:00:49,880 The arctic ocean. 5 00:00:52,360 --> 00:00:56,120 Its surface forms an almost solid platform 6 00:00:56,240 --> 00:00:59,520 that is bigger than the whole of the United States. 7 00:01:04,760 --> 00:01:06,800 Its presence and condition 8 00:01:06,920 --> 00:01:11,560 dominates the lives of all the many and varied animals 9 00:01:11,680 --> 00:01:13,520 that live both on it... 10 00:01:14,600 --> 00:01:16,440 And beneath it. 11 00:01:22,920 --> 00:01:25,720 In the coming months, the sun's warmth 12 00:01:25,840 --> 00:01:30,720 will melt much of it and expose the rich waters beneath. 13 00:01:32,920 --> 00:01:37,040 To survive here, life must adapt to this world 14 00:01:37,160 --> 00:01:40,840 that alternates between ice and water. 15 00:02:00,400 --> 00:02:03,120 After three months of winter darkness, 16 00:02:03,240 --> 00:02:07,640 the sun rises across arctic nonnay. 17 00:02:16,200 --> 00:02:18,760 A newly emerged polar bear mother 18 00:02:18,880 --> 00:02:21,000 encourages her cubs 19 00:02:21,120 --> 00:02:25,840 to take their first tentative steps on the sea ice. 20 00:02:34,000 --> 00:02:37,520 Cubs will stay with their mothers for two years, 21 00:02:37,640 --> 00:02:40,960 learning the skills needed to survive out here. 22 00:02:44,200 --> 00:02:47,680 But thereafter, they will be on their own. 23 00:02:51,720 --> 00:02:54,000 Further out on the sea ice... 24 00:02:55,760 --> 00:02:59,400 This young female bear, less than six years old, 25 00:02:59,520 --> 00:03:02,160 is already fully independent. 26 00:03:06,760 --> 00:03:08,920 She's superbly adapted to life 27 00:03:09,040 --> 00:03:11,120 on the frozen ocean, 28 00:03:11,240 --> 00:03:15,160 protected from the cold by thick, insulating fat 29 00:03:15,280 --> 00:03:17,560 and a double layer of fur. 30 00:03:24,600 --> 00:03:29,000 This time of year is the best time for feeding. 31 00:03:32,640 --> 00:03:35,600 The ringed seals on which she depends 32 00:03:35,720 --> 00:03:37,280 feed on fish, 33 00:03:37,400 --> 00:03:40,280 and are swimming 40 metres beneath her. 34 00:03:42,440 --> 00:03:44,720 But after ten minutes down there, 35 00:03:44,840 --> 00:03:47,800 they must return to the few gaps in the ice 36 00:03:47,920 --> 00:03:50,320 to take a breath and rest. 37 00:03:54,600 --> 00:03:56,560 She has acute hearing 38 00:03:56,680 --> 00:04:00,000 and one of the most sensitive noses in nature. 39 00:04:05,040 --> 00:04:07,800 She can detect a seal's lair beneath two metres 40 00:04:07,920 --> 00:04:09,640 of snow and ice. 41 00:04:12,520 --> 00:04:14,640 Timing is everything. 42 00:04:35,920 --> 00:04:39,240 Only one in ten attempts is successful... 43 00:04:40,280 --> 00:04:44,840 So for a young bear, each meal is very important. 44 00:04:46,480 --> 00:04:49,720 But a male has picked up the scent of the kill. 45 00:05:04,160 --> 00:05:07,360 Large males pose a real threat... 46 00:05:11,480 --> 00:05:15,120 And could inflict fatal injuries in a fight. 47 00:05:21,120 --> 00:05:23,120 But she stands her ground. 48 00:05:36,200 --> 00:05:39,720 Remarkably, rather than fight... 49 00:05:42,520 --> 00:05:44,640 They start to play. 50 00:05:56,720 --> 00:05:57,720 And then, 51 00:05:57,840 --> 00:06:01,320 they set off to explore together. 52 00:06:09,520 --> 00:06:12,360 Well fed and still young, 53 00:06:12,480 --> 00:06:16,000 these two seem to be forming a friendship. 54 00:06:25,680 --> 00:06:28,000 She shows off the swimming skills 55 00:06:28,120 --> 00:06:32,760 that enable her to move with ease between water and ice. 56 00:06:56,320 --> 00:06:57,720 She's behind you! 57 00:07:22,800 --> 00:07:25,080 Dancing on ice... 58 00:07:26,920 --> 00:07:30,120 Apparently just for the joy of it. 59 00:07:50,640 --> 00:07:54,760 After three hours together, they part company... 60 00:07:58,440 --> 00:08:03,400 And return once again to their solitary lives. 61 00:08:16,360 --> 00:08:19,440 Polar bears thrive at this time of year 62 00:08:19,560 --> 00:08:24,560 thanks to the huge platform of sea ice on which they can hunt. 63 00:08:29,720 --> 00:08:31,440 The arctic ocean lies 64 00:08:31,560 --> 00:08:33,560 across the top of the northern hemisphere 65 00:08:33,680 --> 00:08:35,440 and over the north pole itself... 66 00:08:37,240 --> 00:08:39,880 And is surrounded by three continents - 67 00:08:40,000 --> 00:08:43,800 Europe, North America and Asia. 68 00:08:46,600 --> 00:08:49,160 In winter, the sea ice extends 69 00:08:49,280 --> 00:08:53,000 across an area of over five million square miles. 70 00:08:59,480 --> 00:09:02,160 But off the coast of arctic Russia, 71 00:09:02,280 --> 00:09:05,440 a tiny pocket of water has been kept open... 72 00:09:14,400 --> 00:09:19,920 By the continuous stirring of 30 trapped beluga whales. 73 00:09:31,520 --> 00:09:36,520 These four-metre-long arctic whales are superbly adapted 74 00:09:36,640 --> 00:09:40,560 for hunting far beneath the surface of the sea ice. 75 00:09:46,280 --> 00:09:48,440 Nonetheless, being mammals, 76 00:09:48,560 --> 00:09:50,960 they must return to the surface to breathe 77 00:09:51,080 --> 00:09:53,480 every 15 minutes or so. 78 00:09:58,920 --> 00:10:02,640 But this cold spell is exceptionally severe. 79 00:10:04,080 --> 00:10:07,760 And there's not another breathing hole within 20 miles. 80 00:10:13,560 --> 00:10:17,040 Nearby fish and squid disappeared long ago. 81 00:10:18,600 --> 00:10:22,720 These emaciated whales have been imprisoned by the ice 82 00:10:22,840 --> 00:10:26,560 for five months, and they're now starving. 83 00:10:32,840 --> 00:10:35,320 Their only chance of escape will come 84 00:10:35,440 --> 00:10:37,480 when there is a change in the season. 85 00:10:45,760 --> 00:10:49,000 As spring finally reaches the north of the planet, 86 00:10:49,120 --> 00:10:52,760 air temperatures creep above freezing. 87 00:11:08,240 --> 00:11:12,400 The impenetrable ice ceiling begins to fracture. 88 00:11:15,320 --> 00:11:19,360 Small life-saving channels open up... 89 00:11:24,520 --> 00:11:27,040 Bringing freedom. 90 00:11:30,960 --> 00:11:34,880 But spring is a dangerous time for beluga. 91 00:11:35,880 --> 00:11:39,160 As tides and currents pull ice apart, 92 00:11:39,280 --> 00:11:41,640 the beluga find themselves 93 00:11:41,760 --> 00:11:44,080 in a labyrinth of shifting ice floes 94 00:11:44,200 --> 00:11:46,520 that could close their breathing holes 95 00:11:46,640 --> 00:11:49,200 at any point, and so drown them. 96 00:12:01,400 --> 00:12:03,960 Using their sophisticated sonar, 97 00:12:04,080 --> 00:12:06,920 they try to find a way through the icy maze... 98 00:12:20,440 --> 00:12:24,640 And eventually reach a patch of open water. 99 00:12:31,280 --> 00:12:33,800 They're not the only whales here. 100 00:12:40,640 --> 00:12:41,640 Nannhal, 101 00:12:41,720 --> 00:12:43,440 the unicorns of the sea, 102 00:12:43,560 --> 00:12:45,960 are closely related to beluga. 103 00:12:52,520 --> 00:12:54,720 In a rarely seen encounter, 104 00:12:54,840 --> 00:12:58,400 these two kinds of whales appear to socialise. 105 00:13:00,560 --> 00:13:03,360 Who knows what's going on between them? 106 00:13:13,080 --> 00:13:15,520 But soon, they set off together 107 00:13:15,640 --> 00:13:18,640 through the shifting fields of ice... 108 00:13:27,320 --> 00:13:30,400 A journey of up to 1,000 miles... 109 00:13:34,640 --> 00:13:37,400 Before they reach ice-free waters, 110 00:13:37,520 --> 00:13:40,280 where they can rear their young. 111 00:13:55,280 --> 00:13:58,040 As the spring sunshine strengthens, 112 00:13:58,160 --> 00:14:01,520 the broken pack ice off the coast of Greenland 113 00:14:01,640 --> 00:14:04,240 becomes a nursery. 114 00:14:10,280 --> 00:14:12,040 A harp seal pup... 115 00:14:14,000 --> 00:14:16,440 Born just a week ago. 116 00:14:18,400 --> 00:14:20,520 He has little fat. 117 00:14:22,240 --> 00:14:23,280 His thick fur 118 00:14:23,400 --> 00:14:26,680 is his only protection from the arctic chill. 119 00:14:29,760 --> 00:14:33,920 In between dozes, he waits for his mother to return. 120 00:14:42,840 --> 00:14:45,640 She has only one pup a year... 121 00:14:51,720 --> 00:14:55,120 And will produce milk for only 12 days, 122 00:14:55,240 --> 00:14:58,960 one of the shortest nursing periods in nature. 123 00:15:02,800 --> 00:15:04,360 That is just long enough 124 00:15:04,480 --> 00:15:07,680 for him to develop a thick layer of blubber... 125 00:15:09,000 --> 00:15:13,480 Thanks to his mother's milk, which is 50% fat. 126 00:15:18,680 --> 00:15:21,240 And his mother stays alongside 127 00:15:21,360 --> 00:15:24,920 while he learns an important survival skill 128 00:15:25,040 --> 00:15:26,480 for any seal... 129 00:15:40,120 --> 00:15:41,880 How to swim. 130 00:15:44,040 --> 00:15:47,440 He may not be keen to take the plunge. 131 00:15:47,560 --> 00:15:52,280 The salt water is minus two degrees celsius, after all. 132 00:16:02,800 --> 00:16:05,800 Pups start with a doggy paddle. 133 00:16:09,760 --> 00:16:12,560 Mum stays reassuringly close. 134 00:16:25,120 --> 00:16:27,440 Still developing his insulating blubber, 135 00:16:27,560 --> 00:16:30,840 a pup is at risk of hypothermia, 136 00:16:30,960 --> 00:16:32,760 so needs to rest 137 00:16:32,880 --> 00:16:34,600 and warm up. 138 00:16:40,120 --> 00:16:41,120 Each day, 139 00:16:41,240 --> 00:16:44,120 he puts on another two kilos... 140 00:16:50,080 --> 00:16:51,440 And practises swimming 141 00:16:51,560 --> 00:16:53,760 for just a little longer. 142 00:17:08,320 --> 00:17:12,080 Since birth, this pup has tripled in weight, 143 00:17:12,200 --> 00:17:16,480 and he's now at ease in this curious other world. 144 00:17:29,120 --> 00:17:31,600 12 days gone by. 145 00:17:32,920 --> 00:17:36,200 A mother's work is done. 146 00:17:45,280 --> 00:17:49,840 In producing milk, she's lost a third of her body weight. 147 00:17:53,720 --> 00:17:57,600 Now she must return to her feeding grounds. 148 00:18:23,880 --> 00:18:27,040 She will never see her pup again. 149 00:18:43,320 --> 00:18:47,520 The next four weeks he spends alone, 150 00:18:47,640 --> 00:18:50,240 sticking close to the ice platform... 151 00:18:52,920 --> 00:18:56,280 Surviving on his fat reserves 152 00:18:56,400 --> 00:19:00,440 as his downy fleece is replaced by a sleek coat 153 00:19:00,560 --> 00:19:02,520 more suited to swimming. 154 00:19:09,280 --> 00:19:11,200 But temperatures in the arctic are now 155 00:19:11,320 --> 00:19:13,240 rising faster than ever before... 156 00:19:16,200 --> 00:19:19,720 Creating storms that break up the ice floes 157 00:19:19,840 --> 00:19:22,160 earlier each spring. 158 00:19:31,880 --> 00:19:35,720 Harp seal pups are being tipped into freezing waters 159 00:19:35,840 --> 00:19:40,000 before they're ready to endure long periods at sea. 160 00:19:49,760 --> 00:19:52,800 In some pupping areas, 161 00:19:52,920 --> 00:19:55,280 almost none survive. 162 00:20:20,240 --> 00:20:22,400 As spring turns to summer, 163 00:20:22,520 --> 00:20:27,120 life on the sea ice suddenly begins to proliferate. 164 00:20:29,840 --> 00:20:32,080 The daylight increases, 165 00:20:32,200 --> 00:20:34,360 and algae that had remained dormant 166 00:20:34,480 --> 00:20:36,960 within the ice all winter 167 00:20:37,080 --> 00:20:38,960 begin to bloom. 168 00:20:45,240 --> 00:20:48,080 This upside-down Meadow is now cropped 169 00:20:48,200 --> 00:20:49,960 by plankton. 170 00:21:06,360 --> 00:21:09,160 For a little skeleton shrimp 171 00:21:09,280 --> 00:21:12,920 living at the bottom of a towering forest of kelp, 172 00:21:13,040 --> 00:21:15,600 the best way to get a share of the food... 173 00:21:16,760 --> 00:21:18,560 Is to climb. 174 00:21:22,800 --> 00:21:24,880 If you're only two centimetres long... 175 00:21:26,160 --> 00:21:28,840 This is like scaling a skyscraper. 176 00:21:31,640 --> 00:21:35,080 And yet it's not alone. 177 00:21:37,080 --> 00:21:39,280 Hundreds of fellow shrimps 178 00:21:39,400 --> 00:21:42,200 are attempting the same ascent. 179 00:21:47,760 --> 00:21:48,960 A new mother 180 00:21:49,080 --> 00:21:51,520 has parked her brood halfway up. 181 00:21:52,680 --> 00:21:56,400 And she's not about to give way. 182 00:22:09,680 --> 00:22:13,960 This one is a determined commuter. 183 00:22:14,080 --> 00:22:16,920 But the mother's drive to protect her young 184 00:22:17,040 --> 00:22:20,360 is now causing a trafficjam. 185 00:22:28,000 --> 00:22:29,440 At last... 186 00:22:29,560 --> 00:22:32,600 Many have made it to the topmost branches 187 00:22:32,720 --> 00:22:34,920 of this underwater forest. 188 00:22:37,280 --> 00:22:40,160 And it's been well worth the effort. 189 00:22:42,200 --> 00:22:43,880 The prize... 190 00:22:44,000 --> 00:22:45,560 Is a plankton feast... 191 00:22:50,200 --> 00:22:53,000 Raining down from above. 192 00:22:58,160 --> 00:23:02,120 By midsummer, arctic waters are filled 193 00:23:02,240 --> 00:23:03,280 with food... 194 00:23:14,560 --> 00:23:19,080 Making them into one of the richest of all oceans... 195 00:23:23,320 --> 00:23:27,200 Feeding billions of microscopic mouths, 196 00:23:27,320 --> 00:23:28,560 as well as... 197 00:23:29,600 --> 00:23:31,880 The biggest mouth on the planet... 198 00:23:38,480 --> 00:23:40,360 The bowhead whale. 199 00:23:43,680 --> 00:23:46,560 Its four-metre-long baleen plates 200 00:23:46,680 --> 00:23:48,840 enable it to sieve out 201 00:23:48,960 --> 00:23:51,840 up to six tonnes of plankton a day. 202 00:23:54,040 --> 00:24:00,200 And it grows swiftly into an 18-metre 100-tonne giant. 203 00:24:06,840 --> 00:24:10,160 In summer, the bowheads are so well fed 204 00:24:10,280 --> 00:24:13,040 they head for an annual get-together. 205 00:24:24,800 --> 00:24:27,280 After a year of wear and tear, 206 00:24:27,400 --> 00:24:30,760 their skin needs reconditioning. 207 00:24:37,120 --> 00:24:40,160 This is a whale health spa. 208 00:24:49,520 --> 00:24:54,880 Rocks and sand in the shallows are used like pumice stones 209 00:24:55,000 --> 00:24:58,600 with which to rub off dead skin and parasites. 210 00:25:03,440 --> 00:25:06,880 Such places can become very popular. 211 00:25:13,960 --> 00:25:16,320 This bay, off the coast of Russia, 212 00:25:16,440 --> 00:25:18,520 attracts an immense gathering 213 00:25:18,640 --> 00:25:21,000 of over 50 bowheads. 214 00:25:26,920 --> 00:25:30,200 They are the longest-lived of all mammals. 215 00:25:38,080 --> 00:25:41,280 Some are 200 years old 216 00:25:41,400 --> 00:25:44,480 and have been coming here for many decades. 217 00:25:47,880 --> 00:25:51,600 Suddenly, their peace is shattered. 218 00:25:55,880 --> 00:25:59,240 Killer whales have arrived from the south. 219 00:26:02,320 --> 00:26:03,800 Nine metres long, 220 00:26:03,920 --> 00:26:06,000 weighing nine tonnes... 221 00:26:07,400 --> 00:26:10,480 And renowned for their exceptional intelligence... 222 00:26:12,040 --> 00:26:15,840 This particular pack specialises in hunting 223 00:26:15,960 --> 00:26:17,880 bowhead whales. 224 00:26:29,320 --> 00:26:32,240 The bowheads retreat into the shallows... 225 00:26:33,720 --> 00:26:35,800 Where it will be harder 226 00:26:35,920 --> 00:26:38,960 for killer whales to launch an attack. 227 00:26:43,680 --> 00:26:47,520 But the killers can swim much faster than the bowheads. 228 00:26:54,920 --> 00:26:57,920 The group tries to close ranks. 229 00:27:02,800 --> 00:27:05,640 But the killers attempt to separate them. 230 00:27:15,160 --> 00:27:18,760 They look for individual signs of weakness. 231 00:27:30,800 --> 00:27:33,640 In the shallows, the bowheads lash out... 232 00:27:35,760 --> 00:27:38,720 With their seven-metre-wide tails. 233 00:27:53,440 --> 00:27:56,920 But in the confusion, some run aground. 234 00:28:10,920 --> 00:28:13,640 Others try to reach deeper water. 235 00:28:16,480 --> 00:28:19,760 This youngster, half the size of an adult, 236 00:28:19,880 --> 00:28:21,760 is extremely vulnerable. 237 00:28:31,640 --> 00:28:33,160 The killer whales 238 00:28:33,280 --> 00:28:37,120 take turns to ram into its sides... 239 00:28:37,240 --> 00:28:42,000 Cracking its ribs so that it struggles to breathe. 240 00:29:07,320 --> 00:29:12,760 Then they push the youngster down until, finally... 241 00:29:13,800 --> 00:29:15,720 It drowns. 242 00:29:22,760 --> 00:29:24,680 The battle is over. 243 00:29:26,480 --> 00:29:28,880 It lasted an hour. 244 00:29:30,480 --> 00:29:34,840 Yet now the killer whales eat only one part of their prey... 245 00:29:36,480 --> 00:29:39,280 The young bowhead's soft, fatty tongue. 246 00:29:53,840 --> 00:29:56,480 Today, more and more bowheads 247 00:29:56,600 --> 00:29:59,760 are falling prey to killer whales, 248 00:29:59,880 --> 00:30:01,080 as the warming climate 249 00:30:01,200 --> 00:30:03,760 causes the protective barrier ofseaice 250 00:30:03,880 --> 00:30:06,280 to melt earlier each year. 251 00:30:24,760 --> 00:30:29,320 By midsummer, millions of migratory sea birds, 252 00:30:29,440 --> 00:30:32,360 having flown thousands of miles to get here, 253 00:30:32,480 --> 00:30:35,760 are feeding in the arctic's rich waters. 254 00:30:40,320 --> 00:30:41,680 Over a million 255 00:30:41,800 --> 00:30:44,520 crested auklets, no bigger than puffins, 256 00:30:44,640 --> 00:30:47,920 now descend on Alaska's Saint Lawrence island 257 00:30:48,040 --> 00:30:50,840 and are preparing to breed. 258 00:30:55,440 --> 00:31:00,080 To win a mate, a male must try to stand out from the crowd. 259 00:31:02,320 --> 00:31:05,640 And auditions are already under way. 260 00:31:06,960 --> 00:31:11,080 Males and females, unusually, look very similar, 261 00:31:11,200 --> 00:31:15,040 each adorned with an Elvis-like crest. 262 00:31:15,160 --> 00:31:18,960 But it's the size of the crest that matters. 263 00:31:23,000 --> 00:31:25,560 And this male's headgear seems to be 264 00:31:25,680 --> 00:31:27,440 no more than adequate. 265 00:31:32,520 --> 00:31:35,600 A position on the ground is also important. 266 00:31:40,640 --> 00:31:46,280 One large male wants this particular perch... 267 00:31:55,720 --> 00:31:59,200 And having got it, he breaks into song. 268 00:32:09,360 --> 00:32:13,440 He now releases a potent tangerine scent 269 00:32:13,560 --> 00:32:14,960 from the back of his neck... 270 00:32:16,080 --> 00:32:18,840 And a mob of fans go wild. 271 00:32:24,720 --> 00:32:26,200 This male, however, 272 00:32:26,320 --> 00:32:28,360 seems to have nothing to offer. 273 00:32:32,960 --> 00:32:36,480 But a gaggle of groupies can be a dangerous distraction. 274 00:32:41,360 --> 00:32:43,240 An arctic fox. 275 00:33:10,000 --> 00:33:11,720 It's found an egg. 276 00:33:15,200 --> 00:33:17,200 With the stage cleared, 277 00:33:17,320 --> 00:33:21,120 the highest perch has become vacant. 278 00:33:41,760 --> 00:33:45,120 This is a moment to shine. 279 00:33:57,760 --> 00:34:00,480 His display doesn't go unnoticed. 280 00:34:05,920 --> 00:34:09,840 And his tangerine perfume attracts an admirer. 281 00:34:18,520 --> 00:34:20,880 And not just one. 282 00:34:25,120 --> 00:34:28,600 Now it's down to the females to impress him. 283 00:34:32,320 --> 00:34:35,200 In auklet society, both sexes 284 00:34:35,320 --> 00:34:38,200 have a say when it comes to choosing a mate. 285 00:34:49,520 --> 00:34:51,120 At the height of summer, 286 00:34:51,240 --> 00:34:54,040 with 24 hours of sunlight a day, 287 00:34:54,160 --> 00:34:57,640 over half the sea ice melts away. 288 00:35:04,680 --> 00:35:06,880 The beaches of Svalbard 289 00:35:07,000 --> 00:35:09,920 provide safe places to haul out 290 00:35:10,040 --> 00:35:13,480 for one of the arctic's special residents... 291 00:35:17,880 --> 00:35:19,680 Walruses. 292 00:35:22,440 --> 00:35:24,680 They forage for shellfish 293 00:35:24,800 --> 00:35:27,680 for up to 17 hours at a stretch. 294 00:35:32,240 --> 00:35:33,320 Now... 295 00:35:35,160 --> 00:35:37,240 It's time for a rest. 296 00:35:41,480 --> 00:35:46,000 Each adult male weighs more than a tonne. 297 00:35:51,320 --> 00:35:53,000 And heaving oneself over the sand... 298 00:35:55,200 --> 00:35:56,720 Without the support of water 299 00:35:56,840 --> 00:35:58,760 is very hard work. 300 00:36:05,240 --> 00:36:09,360 This male has a particular sunbathing spot in mind... 301 00:36:13,120 --> 00:36:14,720 Right in the middle 302 00:36:14,840 --> 00:36:17,080 of the 50-strong huddle. 303 00:36:26,760 --> 00:36:28,560 A prod helps in parting the crowd. 304 00:36:42,400 --> 00:36:44,320 Almost in. 305 00:36:54,600 --> 00:36:57,080 At last, he can settle down for a snooze... 306 00:36:58,120 --> 00:36:59,240 Swaddled on all sides 307 00:36:59,360 --> 00:37:01,800 by the bodies of his neighbours. 308 00:37:05,200 --> 00:37:08,840 But it's not a peaceful spot. 309 00:37:18,440 --> 00:37:22,760 Sleep isn't easy when a fidgety bedfellow 310 00:37:22,880 --> 00:37:24,800 decides that he has an itch 311 00:37:24,920 --> 00:37:27,080 that needs scratching. 312 00:37:28,320 --> 00:37:30,600 This is the time to moult, 313 00:37:30,720 --> 00:37:34,160 to get rid of one's old fur with all its parasites, 314 00:37:34,280 --> 00:37:38,120 and expose the healthy new coat beneath. 315 00:37:51,120 --> 00:37:53,640 These days, Svalbard's summer temperatures 316 00:37:53,760 --> 00:37:57,160 can soar to 22 degrees celsius. 317 00:38:04,760 --> 00:38:07,920 Flushing red by bringing blood close to the skin 318 00:38:08,040 --> 00:38:10,720 helps them to keep cool. 319 00:38:16,360 --> 00:38:19,800 But some overheating is unavoidable... 320 00:38:21,960 --> 00:38:24,920 Especially for a big male. 321 00:38:34,760 --> 00:38:36,760 Enough is enough. 322 00:38:44,000 --> 00:38:46,040 Getting up here... 323 00:38:46,160 --> 00:38:47,400 Was a slog. 324 00:38:48,440 --> 00:38:52,480 But this male has found a better way of getting down. 325 00:38:53,520 --> 00:38:56,240 Let gravity do the work. 326 00:39:27,800 --> 00:39:31,280 Now, that... is cool. 327 00:39:33,280 --> 00:39:35,200 Ahhh! 328 00:39:40,240 --> 00:39:42,760 Everyone is doing it. 329 00:39:42,880 --> 00:39:45,440 It saves both time and energy. 330 00:39:50,080 --> 00:39:53,760 But walruses will need all the tricks they can find. 331 00:39:57,000 --> 00:39:59,880 The arctic is warming, 332 00:40:00,000 --> 00:40:03,640 and these cold-loving animals are facing 333 00:40:03,760 --> 00:40:05,400 a precarious future. 334 00:40:16,120 --> 00:40:20,520 For millennia, the arctic ocean has frozen over in the winter 335 00:40:20,640 --> 00:40:22,600 and then gradually melted 336 00:40:22,720 --> 00:40:25,560 throughout the spring and summer. 337 00:40:27,000 --> 00:40:29,080 But in the last 40 years, 338 00:40:29,200 --> 00:40:34,280 the extent of the summer sea ice has declined by 50%. 339 00:40:37,000 --> 00:40:40,200 Some predict that it will be ice free 340 00:40:40,320 --> 00:40:42,840 as early as 2035. 341 00:40:47,000 --> 00:40:48,880 This profound change... 342 00:40:50,000 --> 00:40:51,800 Is already having an impact 343 00:40:51,920 --> 00:40:55,640 on the arctic ocean's highly specialised wildlife. 344 00:41:01,560 --> 00:41:05,120 With less summer sea ice from which to hunt seals, 345 00:41:05,240 --> 00:41:08,840 some polar bears are now travelling up to 400 miles... 346 00:41:10,320 --> 00:41:13,560 Swimming continuously for up to ten days 347 00:41:13,680 --> 00:41:15,400 in search of land. 348 00:41:22,760 --> 00:41:25,680 Wrangel island, off arctic Russia... 349 00:41:26,920 --> 00:41:31,200 The only land for almost 100 miles. 350 00:41:34,520 --> 00:41:38,800 Each summer, more and more polar bears come ashore here. 351 00:41:46,800 --> 00:41:49,000 This newly arrived mother 352 00:41:49,120 --> 00:41:51,760 needs to find food for her family... 353 00:41:57,600 --> 00:42:01,760 But knows not to approach other adult bears. 354 00:42:05,080 --> 00:42:06,880 A full-grown male 355 00:42:07,000 --> 00:42:09,120 can kill and eat a cub, 356 00:42:09,240 --> 00:42:13,280 and will do so if other food is in short supply. 357 00:42:15,320 --> 00:42:19,680 There are over 1,000 bears on this one island. 358 00:42:23,160 --> 00:42:27,920 It's the greatest concentration of polar bears on the planet. 359 00:42:34,360 --> 00:42:38,200 But there is food to be had on these remote shores. 360 00:42:42,520 --> 00:42:43,960 A walrus colony... 361 00:42:46,200 --> 00:42:48,000 2,000 strong. 362 00:42:57,960 --> 00:43:00,600 The walruses panic. 363 00:43:13,600 --> 00:43:16,200 And there are casualties. 364 00:43:37,600 --> 00:43:40,680 Fights break out. 365 00:43:47,320 --> 00:43:51,200 This is no place for a young family. 366 00:43:58,320 --> 00:44:01,200 The mother calls her cubs away. 367 00:44:17,800 --> 00:44:20,200 They must search elsewhere. 368 00:44:39,000 --> 00:44:43,440 Grass is a poor meal for a growing cub... 369 00:44:44,800 --> 00:44:48,320 And starvation in summer is a real threat. 370 00:44:59,520 --> 00:45:02,280 But this opportunity to feed... 371 00:45:03,320 --> 00:45:05,560 Is one she cannot afford to ignore. 372 00:45:11,240 --> 00:45:13,280 It's time to gamble. 373 00:45:19,080 --> 00:45:20,600 Her cubs follow her. 374 00:45:22,840 --> 00:45:24,880 She urges them to stay back. 375 00:45:40,280 --> 00:45:42,680 The males are twice her size... 376 00:45:44,040 --> 00:45:46,560 But, preoccupied with feeding, 377 00:45:46,680 --> 00:45:48,880 they tolerate her presence. 378 00:45:54,400 --> 00:45:57,040 The distress calls of her cubs, however... 379 00:45:58,360 --> 00:45:59,840 Attract unwelcome attention. 380 00:46:17,280 --> 00:46:20,680 Their mother rushes to shield them with her body. 381 00:46:28,880 --> 00:46:32,800 But she seems torn between guarding her family 382 00:46:32,920 --> 00:46:34,840 and feeding herself. 383 00:46:50,360 --> 00:46:52,720 Cubs left by themselves 384 00:46:52,840 --> 00:46:56,480 are easy prey for a hungry male bear. 385 00:47:06,320 --> 00:47:10,920 But now her maternal instincts take over. 386 00:47:33,520 --> 00:47:36,400 Faced with a mother's fury, 387 00:47:36,520 --> 00:47:38,920 the dominant male backs down. 388 00:48:02,240 --> 00:48:04,040 Having fought her way in... 389 00:48:05,920 --> 00:48:07,880 Her cubs can now feed 390 00:48:08,000 --> 00:48:10,360 for the first time in weeks. 391 00:48:19,680 --> 00:48:21,360 Polar bears were once 392 00:48:21,480 --> 00:48:23,040 the supreme hunters 393 00:48:23,160 --> 00:48:25,120 on the sea ice. 394 00:48:25,240 --> 00:48:26,680 Now, each summer, 395 00:48:26,800 --> 00:48:28,480 more and more of them 396 00:48:28,600 --> 00:48:30,000 have to come to land 397 00:48:30,120 --> 00:48:32,280 in search of food. 398 00:48:37,080 --> 00:48:40,680 Whether the ice bear survives into the next century 399 00:48:40,800 --> 00:48:45,280 depends on what happens to the sea ice on which they rely. 400 00:48:48,640 --> 00:48:53,400 As with all of the arctic ocean's remarkable wildlife, 401 00:48:53,520 --> 00:48:56,920 it's how the climate changes over the coming years 402 00:48:57,040 --> 00:48:59,800 that will determine their future. 403 00:49:16,920 --> 00:49:19,560 In today's unpredictable and changing arctic, 404 00:49:19,680 --> 00:49:23,520 filming its wildlife is an ever-increasing challenge... 405 00:49:25,960 --> 00:49:28,360 None more so than trying to capture the brief time 406 00:49:28,480 --> 00:49:30,800 that a mother harp seal spends 407 00:49:30,920 --> 00:49:33,120 preparing her pup for life at sea. 408 00:49:37,520 --> 00:49:40,160 To find the seal's pupping grounds, 409 00:49:40,280 --> 00:49:43,200 the crew have sailed to a remote area of the arctic 410 00:49:43,320 --> 00:49:45,720 off the east coast of Greenland. 411 00:49:46,880 --> 00:49:48,920 But here, they quickly discover 412 00:49:49,040 --> 00:49:51,920 that its usually solid platform of sea ice 413 00:49:52,040 --> 00:49:55,040 has broken up into thousands of floes. 414 00:49:56,040 --> 00:49:58,720 It's a surprising sight even for veteran captain 415 00:49:58,840 --> 00:50:00,680 bjorne kvernmo. 416 00:50:13,040 --> 00:50:15,720 And with the sea ice so fractured, 417 00:50:15,840 --> 00:50:17,560 there's no sign of any wildlife. 418 00:50:18,840 --> 00:50:22,480 We've been at sea for well over a week now. 419 00:50:22,600 --> 00:50:25,640 We still haven't filmed a thing. 420 00:50:26,840 --> 00:50:30,720 With mother and pup together for just 12 days, it's a race 421 00:50:30,840 --> 00:50:32,880 to find the dense pack ice 422 00:50:33,000 --> 00:50:35,960 on which the breeding seals give birth. 423 00:50:38,360 --> 00:50:42,040 The team head a further 100 miles up the Greenland coast, 424 00:50:42,160 --> 00:50:44,560 to an area no film crew 425 00:50:44,680 --> 00:50:46,400 has ventured into before. 426 00:50:48,600 --> 00:50:51,240 Their gamble pays off. 427 00:50:54,880 --> 00:50:57,840 Our first harp seal baby! 428 00:50:57,960 --> 00:51:01,320 From the smaller, more manoeuvrable tender, 429 00:51:01,440 --> 00:51:03,600 cameraman Jamie mcpherson 430 00:51:03,720 --> 00:51:05,480 hopes to record the precious time 431 00:51:05,600 --> 00:51:07,160 mother and pup spend together 432 00:51:07,280 --> 00:51:08,560 on the ice. 433 00:51:08,680 --> 00:51:09,736 I've been filming 434 00:51:09,760 --> 00:51:12,000 probably one of the cutest animals in the world. 435 00:51:12,120 --> 00:51:13,280 And there was suckling, 436 00:51:13,400 --> 00:51:15,320 which is really cool, because it's really funny, 437 00:51:15,440 --> 00:51:17,136 because the baby goes from one nipple to the other nipple 438 00:51:17,160 --> 00:51:19,600 and just goes backwards and fonnards. 439 00:51:24,400 --> 00:51:27,560 That's one of the sweetest things I've ever seen! 440 00:51:27,680 --> 00:51:29,800 Utterly adorable! 441 00:51:31,240 --> 00:51:33,760 With mum now calling it into the water, 442 00:51:33,880 --> 00:51:37,520 this pup may be ready for its very first swim. 443 00:51:39,120 --> 00:51:41,760 It's the cue for underwater cameraman 444 00:51:41,880 --> 00:51:43,240 Hugh Miller. 445 00:51:44,480 --> 00:51:45,960 We're going to try something different 446 00:51:46,040 --> 00:51:47,880 and actually get into the water with the seals. 447 00:51:47,960 --> 00:51:51,160 We're definitely in new territory here. 448 00:51:53,280 --> 00:51:55,560 To film this rare moment under water, 449 00:51:55,680 --> 00:51:57,680 Hugh will need to get a lot closer 450 00:51:57,800 --> 00:51:59,440 without disturbing them. 451 00:52:01,600 --> 00:52:04,720 But with arctic waters at minus two degrees celsius, 452 00:52:04,840 --> 00:52:08,840 even with a protective thermal dry suit, 453 00:52:08,960 --> 00:52:13,600 Hugh only has an hour before he risks developing hypothermia. 454 00:52:16,200 --> 00:52:20,720 It's now a matter of waiting for the pup to take the plunge. 455 00:52:21,720 --> 00:52:24,160 The guys have now beeninforabout" 456 00:52:27,280 --> 00:52:28,400 20 minutes. 457 00:52:29,880 --> 00:52:33,720 I can guarantee you they'll be freezing cold. 458 00:52:35,000 --> 00:52:38,960 Hugh's body temperature is getting dangerously low. 459 00:52:45,120 --> 00:52:47,120 Hugh: Conditions have been... 460 00:52:47,240 --> 00:52:49,040 Really hard. 461 00:52:49,160 --> 00:52:50,640 The cold just... 462 00:52:52,520 --> 00:52:54,200 It's been very, very difficult! 463 00:52:55,240 --> 00:52:56,840 Da vid: With less than a week to go 464 00:52:56,960 --> 00:52:59,400 before this mother is likely to leave her pup for ever, 465 00:52:59,520 --> 00:53:03,400 Jamie continues to capture their intimate interactions... 466 00:53:08,880 --> 00:53:11,240 While Hugh is yet to film a single shot. 467 00:53:13,120 --> 00:53:14,560 To make matters worse, 468 00:53:14,680 --> 00:53:19,480 temperatures fall to minus 30 degrees centigrade. 469 00:53:20,600 --> 00:53:22,560 And as the wind direction changes, 470 00:53:22,680 --> 00:53:26,240 the floes are forced closer together. 471 00:53:26,360 --> 00:53:28,880 Pack ice has just come in from all around us. 472 00:53:29,000 --> 00:53:30,440 It could flip the boat, 473 00:53:30,560 --> 00:53:32,160 and that would be the end of the shoot. 474 00:53:33,560 --> 00:53:36,120 Hemmed in by blocks 475 00:53:36,240 --> 00:53:38,520 weighing several tonnes, the small skiffs 476 00:53:38,640 --> 00:53:40,560 are at risk of getting crushed. 477 00:53:41,680 --> 00:53:43,800 They radio for help. 478 00:53:43,920 --> 00:53:46,520 But as the mother ship approaches, she shunts 479 00:53:46,640 --> 00:53:48,760 even more ice their way. 480 00:53:53,120 --> 00:53:55,680 So, we've got these big chunks of ice either side of us 481 00:53:55,800 --> 00:53:58,120 and they've got to go somewhere, so... 482 00:53:59,920 --> 00:54:02,880 With help three days away, the crew 483 00:54:03,000 --> 00:54:05,760 can't afford any mistakes. 484 00:54:11,120 --> 00:54:14,320 In the Nick of time, a lifeline. 485 00:54:18,760 --> 00:54:20,320 Safely aboard! 486 00:54:21,320 --> 00:54:23,200 That was a bit full-on! 487 00:54:26,880 --> 00:54:30,120 By the next day, the pack ice has drifted apart. 488 00:54:31,160 --> 00:54:33,840 And not a moment too soon. 489 00:54:43,280 --> 00:54:45,240 Rachel: Awww! 490 00:54:49,200 --> 00:54:51,920 Jamie: We just saw it go for its first swim. 491 00:54:52,920 --> 00:54:53,920 It was amazing. 492 00:54:54,040 --> 00:54:57,280 It just sort of flops about on the surface. It was very cool. 493 00:55:00,200 --> 00:55:04,480 With the pup finally in the water, Hugh seizes his chance. 494 00:55:05,880 --> 00:55:09,520 But what will the pup make of this curious sea creature? 495 00:55:14,320 --> 00:55:18,800 This pup is playing with - playing with! - The camera. 496 00:55:18,920 --> 00:55:21,480 I can see Hugh's smile from here. 497 00:55:23,240 --> 00:55:25,920 Hugh: Oh, lovely. Wow! 498 00:55:27,520 --> 00:55:29,160 That was great! 499 00:55:29,280 --> 00:55:31,520 - Yeah, we saw. - That was great! 500 00:55:31,640 --> 00:55:33,360 Hugh: So nice. 501 00:55:36,080 --> 00:55:38,480 Just as Hugh gets his reward, 502 00:55:38,600 --> 00:55:41,760 the arctic conditions take a turn for the worse. 503 00:55:43,240 --> 00:55:44,760 We've been getting some amazing stuff, 504 00:55:44,880 --> 00:55:48,360 but now the wind's picked up, so we're trying to get out. 505 00:55:50,560 --> 00:55:52,000 With a storm brewing, 506 00:55:52,120 --> 00:55:55,600 not even the mother ship is safe among the ice floes. 507 00:55:55,720 --> 00:56:00,720 The crew have no choice but to leave the seals behind. 508 00:56:08,160 --> 00:56:10,520 It would roll in by the storm? 509 00:56:12,560 --> 00:56:14,000 And they drown? 510 00:56:21,680 --> 00:56:25,880 Today, the combination of reduced arctic sea ice 511 00:56:26,000 --> 00:56:27,640 and heavy storms 512 00:56:27,760 --> 00:56:31,080 is leading to more and more tragedies like this. 513 00:56:33,840 --> 00:56:35,280 Unless this trend is reversed, 514 00:56:35,400 --> 00:56:39,040 the future for much of the arctic's unique wildlife 515 00:56:39,160 --> 00:56:41,240 hangs in the balance.