1 00:00:00,000 --> 00:00:01,810 (inspirational music) 2 00:00:01,810 --> 00:00:05,630 - [Announcer] Antarctica, a vast, icy desert. 3 00:00:05,630 --> 00:00:09,283 In terms of rainfall, it's the driest place on Earth, 4 00:00:11,480 --> 00:00:14,590 and yet the Antarctic holds more than two-thirds 5 00:00:14,590 --> 00:00:16,173 of the planet's fresh water. 6 00:00:17,440 --> 00:00:20,523 With plunging temperatures and powerful winds, 7 00:00:21,660 --> 00:00:24,853 our southernmost landmass is an unrelenting habitat, 8 00:00:26,500 --> 00:00:29,933 but life persists and thrives. 9 00:00:30,830 --> 00:00:33,970 Once part of a connected southern supercontinent, 10 00:00:33,970 --> 00:00:36,680 Antarctica is now isolated by a current 11 00:00:36,680 --> 00:00:39,700 so powerful it creates undersea highways 12 00:00:39,700 --> 00:00:41,763 back to each and every continent, 13 00:00:42,600 --> 00:00:47,310 where extraordinary lifeforms answer the call of the seasons 14 00:00:47,310 --> 00:00:52,113 on icy islands and on a land frozen by time. 15 00:01:00,670 --> 00:01:03,823 This is the Wildest Antarctic. 16 00:01:07,510 --> 00:01:08,930 - [Narrator] Antarctica is surrounded 17 00:01:08,930 --> 00:01:12,080 by the strongest ocean current on the planet. 18 00:01:12,080 --> 00:01:15,200 It's a force that extends right from the surface 19 00:01:15,200 --> 00:01:16,973 all the way to the sea floor. 20 00:01:18,160 --> 00:01:19,710 It's one of the many variables 21 00:01:19,710 --> 00:01:22,540 that keeps this continent isolated 22 00:01:22,540 --> 00:01:24,883 and the coldest place on Earth. 23 00:01:26,800 --> 00:01:31,800 Antarctica spans the South Pole some 15 million kilometers, 24 00:01:32,040 --> 00:01:36,973 roughly the size of the United States and Mexico combined. 25 00:01:38,200 --> 00:01:40,020 Here temperatures can plummet 26 00:01:40,020 --> 00:01:43,563 as low as 90 degrees celsius below zero. 27 00:01:44,820 --> 00:01:47,183 It's also the windiest place on Earth. 28 00:01:48,500 --> 00:01:50,560 Wind speed on one cape has been measured 29 00:01:50,560 --> 00:01:53,185 at over 300 kilometers an hour. 30 00:01:53,185 --> 00:01:55,740 (serene music) 31 00:01:55,740 --> 00:02:00,603 Some valleys have not seen rain in some two million years. 32 00:02:02,910 --> 00:02:05,903 Antarctica was once as warm as modern California, 33 00:02:07,030 --> 00:02:10,460 covered in lush forest and roaming dinosaurs, 34 00:02:10,460 --> 00:02:12,630 when it was still joined to Africa, 35 00:02:12,630 --> 00:02:14,950 South America, and Australia 36 00:02:14,950 --> 00:02:18,293 in the ancient supercontinent of Gondwana. 37 00:02:19,210 --> 00:02:23,330 Since freezing over completely some 20 million years ago, 38 00:02:23,330 --> 00:02:26,350 ice has locked in huge mountain ranges, 39 00:02:26,350 --> 00:02:28,113 frozen lakes in time, 40 00:02:29,190 --> 00:02:31,903 and created enormous glacial structures. 41 00:02:34,050 --> 00:02:36,540 The Antarctic Circumpolar Current 42 00:02:36,540 --> 00:02:41,280 perpetually moves eastward some 21,000 kilometers. 43 00:02:41,280 --> 00:02:46,280 It carries 170 million cubic meters of water every second. 44 00:02:48,490 --> 00:02:52,290 It's the equivalent of 68,000 Olympic swimming pools. 45 00:02:52,290 --> 00:02:54,600 (empowering music) 46 00:02:54,600 --> 00:02:58,400 The circumpolar current connects the world's oceans, 47 00:02:58,400 --> 00:03:00,610 influencing currents to the north 48 00:03:00,610 --> 00:03:03,280 and creating pathways for polar inhabitants 49 00:03:03,280 --> 00:03:04,993 to travel to other shores. 50 00:03:08,600 --> 00:03:09,920 Currents determine where this 51 00:03:09,920 --> 00:03:11,833 extraordinary marine life will travel, 52 00:03:13,930 --> 00:03:17,713 where they will mate, raise their young, and hunt. 53 00:03:22,860 --> 00:03:24,870 These currents touch on the southern capes 54 00:03:24,870 --> 00:03:28,240 of our continents, the countries where 55 00:03:28,240 --> 00:03:30,563 lions share borders with penguins, 56 00:03:31,890 --> 00:03:34,343 kangaroos overlook seal colonies, 57 00:03:35,370 --> 00:03:39,303 and orcas stalk beaches under the South American sun. 58 00:03:41,710 --> 00:03:44,940 Antarctica appears to have less animal diversity 59 00:03:44,940 --> 00:03:49,940 than other regions, but the surprisingly varied terrains 60 00:03:49,960 --> 00:03:53,457 force each group to adapt in different ways. 61 00:03:53,457 --> 00:03:56,457 (walruses grunting) 62 00:03:59,273 --> 00:04:01,100 (serene music) 63 00:04:01,100 --> 00:04:04,610 Brown Bluff is on the Antarctic continent itself, 64 00:04:04,610 --> 00:04:06,883 near the tip of the Antarctic Peninsula. 65 00:04:08,880 --> 00:04:11,570 The peninsula is a long arm of land and ice 66 00:04:11,570 --> 00:04:13,923 that reaches out toward South America. 67 00:04:15,830 --> 00:04:18,480 Excluding islands, it's Antarctica's 68 00:04:18,480 --> 00:04:20,943 closest point to any other continent. 69 00:04:25,730 --> 00:04:29,780 The bluff itself is a towering basalt and lava cliff 70 00:04:29,780 --> 00:04:31,623 rising up from the beach. 71 00:04:34,230 --> 00:04:37,450 The rock is a remnant of a massive ancient volcano 72 00:04:37,450 --> 00:04:40,373 that erupted through ice over a million years ago. 73 00:04:43,860 --> 00:04:47,000 The brown cliff is peppered with glass, 74 00:04:47,000 --> 00:04:50,580 a result of the intense process of lava rising and cooling 75 00:04:50,580 --> 00:04:53,533 so quickly in subglacial conditions. 76 00:04:55,340 --> 00:04:58,783 It overlooks a three kilometer long bouldered beach. 77 00:05:00,850 --> 00:05:02,603 Vegetation is sparse. 78 00:05:03,460 --> 00:05:07,210 Lichen and moss cover rocks well up into the cliffs, 79 00:05:07,210 --> 00:05:09,530 favoring areas of fresh water runoff 80 00:05:09,530 --> 00:05:11,374 from the melting glaciers. 81 00:05:11,374 --> 00:05:14,124 (water gurgling) 82 00:05:15,260 --> 00:05:17,180 However, it's difficult to get a glimpse 83 00:05:17,180 --> 00:05:20,352 of the terrain at Brown Bluff, as it's covered in these: 84 00:05:20,352 --> 00:05:21,365 (penguins chattering) 85 00:05:21,365 --> 00:05:22,610 (impish music) 86 00:05:22,610 --> 00:05:23,703 Adelie penguins. 87 00:05:26,400 --> 00:05:29,403 East Antarctica is home to six million Adelies. 88 00:05:32,020 --> 00:05:33,610 The few kilometers of Brown Bluff 89 00:05:33,610 --> 00:05:35,930 is one of the largest colonies, 90 00:05:35,930 --> 00:05:38,293 around 20,000 breeding pairs. 91 00:05:41,420 --> 00:05:43,490 At 70 centimeters tall, 92 00:05:43,490 --> 00:05:45,610 the Adelie is precisely mid-range 93 00:05:45,610 --> 00:05:47,523 when it comes to penguin sizes. 94 00:05:49,100 --> 00:05:51,803 Adelies have white rings around their eyes. 95 00:05:54,380 --> 00:05:55,990 There isn't much noticeable difference 96 00:05:55,990 --> 00:05:57,683 between males and females. 97 00:05:59,630 --> 00:06:03,150 There are almost 20 types of penguin worldwide, 98 00:06:03,150 --> 00:06:04,880 but only four of them actually live 99 00:06:04,880 --> 00:06:06,913 on the Antarctic continent itself. 100 00:06:09,950 --> 00:06:12,610 Adelies have soft feet with sharp talons, 101 00:06:12,610 --> 00:06:15,270 designed to walk across ice and rocks 102 00:06:15,270 --> 00:06:17,963 and to scale the steep slopes of these beaches, 103 00:06:19,501 --> 00:06:22,880 though the cliffs here are more difficult than most. 104 00:06:27,730 --> 00:06:31,570 In October, the start of the Antarctic warming months, 105 00:06:31,570 --> 00:06:34,053 male Adelies come ashore in droves. 106 00:06:34,910 --> 00:06:36,970 The transition from porpoising in the sea 107 00:06:36,970 --> 00:06:39,353 to stumbling on land is less than graceful, 108 00:06:40,500 --> 00:06:41,970 but this is the last leg of a race 109 00:06:41,970 --> 00:06:44,504 to reach the Bluff Beach as soon as possible. 110 00:06:44,504 --> 00:06:47,254 (spirited music) 111 00:06:51,170 --> 00:06:53,090 How quickly they can get to work 112 00:06:53,090 --> 00:06:54,500 will have an important bearing 113 00:06:54,500 --> 00:06:56,050 on their breeding season ahead. 114 00:06:59,380 --> 00:07:02,750 The Adelie males make the opening courting overture 115 00:07:02,750 --> 00:07:04,083 by building a nest. 116 00:07:05,690 --> 00:07:08,000 Their goal is to woo a female 117 00:07:08,000 --> 00:07:09,923 with the largest nest possible. 118 00:07:11,670 --> 00:07:13,980 However these penguins aren't exactly 119 00:07:13,980 --> 00:07:16,933 spoiled for choice when it comes to building materials. 120 00:07:21,070 --> 00:07:23,610 The nest is simply a pile of small rocks 121 00:07:23,610 --> 00:07:25,023 collected from the beach. 122 00:07:30,420 --> 00:07:32,730 But it's where they stack their nests 123 00:07:32,730 --> 00:07:34,883 that adds that little extra appeal. 124 00:07:36,920 --> 00:07:40,160 The higher up the bluff, the drier the nest 125 00:07:40,160 --> 00:07:42,220 and the more likely the female is 126 00:07:42,220 --> 00:07:44,103 to choose that nest builder. 127 00:07:44,958 --> 00:07:48,125 (penguins chattering) 128 00:07:53,502 --> 00:07:55,570 The long march from shore to the higher sites 129 00:07:55,570 --> 00:07:57,410 can quickly become crowded 130 00:07:57,410 --> 00:08:00,563 with industrious males and appraising females. 131 00:08:06,380 --> 00:08:08,330 These penguins are not above stealing 132 00:08:08,330 --> 00:08:11,333 from their neighbor if the opportunity arises. 133 00:08:18,240 --> 00:08:20,820 When Adelies have paired off and laid their eggs, 134 00:08:20,820 --> 00:08:22,973 both parents take turns at egg sittings. 135 00:08:24,390 --> 00:08:26,383 They need to remain vigilant. 136 00:08:27,620 --> 00:08:29,920 The further the penguins are from shore, 137 00:08:29,920 --> 00:08:33,193 the safer they are from sea predators like leopard seals, 138 00:08:34,810 --> 00:08:37,033 but they are closer to threat from above: 139 00:08:38,120 --> 00:08:41,623 the Antarctic's ultimate predator from the air, a Skua. 140 00:08:44,360 --> 00:08:47,530 Skuas are a large south polar bird. 141 00:08:47,530 --> 00:08:49,980 They can reach lengths of more than half a meter. 142 00:08:51,980 --> 00:08:54,130 Ferocious anglers, they'll hunt 143 00:08:54,130 --> 00:08:56,283 fish and crustaceans close to shore, 144 00:08:57,500 --> 00:08:59,880 but in the penguin breeding months, 145 00:08:59,880 --> 00:09:02,163 eggs are a seasonal bounty. 146 00:09:06,750 --> 00:09:09,880 It only takes one parent to be fishing at sea 147 00:09:09,880 --> 00:09:12,760 and the other to take a brief break from nest duty 148 00:09:12,760 --> 00:09:15,083 for a Skua to seize opportunity. 149 00:09:18,120 --> 00:09:20,290 The Adelie sees the Skua at work 150 00:09:20,290 --> 00:09:22,323 as it returns uphill to its nest. 151 00:09:26,230 --> 00:09:28,593 There's only time for the briefest of pauses. 152 00:09:29,750 --> 00:09:31,960 Adelies usually lay two eggs, 153 00:09:31,960 --> 00:09:34,360 and there's still time to get back to the other. 154 00:09:38,596 --> 00:09:41,310 An heir and a spare is the breeding 155 00:09:41,310 --> 00:09:43,801 strategy of these penguins. 156 00:09:43,801 --> 00:09:46,095 (penguins chattering) 157 00:09:46,095 --> 00:09:48,678 (serene music) 158 00:09:58,790 --> 00:10:02,090 One chick will hatch just days ahead of the other, 159 00:10:02,090 --> 00:10:05,053 but it will use the slim head start to full advantage. 160 00:10:09,660 --> 00:10:12,570 The elder sibling dominates the nest. 161 00:10:12,570 --> 00:10:15,000 It stands over the later arrival, 162 00:10:15,000 --> 00:10:17,010 reaching in to the adult beak 163 00:10:17,010 --> 00:10:19,390 for the best morsels of food. 164 00:10:19,390 --> 00:10:20,840 It even maneuvers into position 165 00:10:20,840 --> 00:10:23,053 to stay closest to the parent's warmth. 166 00:10:26,440 --> 00:10:29,280 Often both chicks survive, 167 00:10:29,280 --> 00:10:33,529 but if food is scarce the stronger one will be favored. 168 00:10:33,529 --> 00:10:37,258 (penguins chattering) 169 00:10:37,258 --> 00:10:40,258 (inquisitive music) 170 00:10:47,331 --> 00:10:50,498 (penguins chattering) 171 00:10:54,150 --> 00:10:56,140 It takes just a few weeks for the chicks 172 00:10:56,140 --> 00:10:59,283 to put on weight and reach half the size of an adult. 173 00:11:03,370 --> 00:11:06,890 When parents change the guard for fishing and feeding duty, 174 00:11:06,890 --> 00:11:09,713 they do so with noise and celebration. 175 00:11:12,950 --> 00:11:16,380 This serenading ceremony of welcome and farewell 176 00:11:16,380 --> 00:11:18,380 is thought to strengthen the pair bond 177 00:11:18,380 --> 00:11:19,893 of the dutiful parents. 178 00:11:22,100 --> 00:11:24,713 The males are also showing how robust they are. 179 00:11:26,400 --> 00:11:28,040 A penguin can lose weight faster 180 00:11:28,040 --> 00:11:29,663 in these long days without food. 181 00:11:31,410 --> 00:11:34,553 A fat penguin is a noisy and healthy one. 182 00:11:36,373 --> 00:11:38,640 With the bulk of nesting left to the males, 183 00:11:38,640 --> 00:11:41,190 they'll lose weight in the early days of parenting. 184 00:11:43,708 --> 00:11:46,875 (penguins chattering) 185 00:11:48,074 --> 00:11:50,040 By three or four weeks of age, 186 00:11:50,040 --> 00:11:53,093 the Adelie chicks are large enough to be left on their own, 187 00:11:56,500 --> 00:11:59,543 but their growing girth means they are ever hungry. 188 00:12:02,020 --> 00:12:05,360 Both parents must go to sea now to hunt enough krill 189 00:12:05,360 --> 00:12:08,163 and fish for themselves and their brood. 190 00:12:12,810 --> 00:12:15,100 Warmed by thick brown jackets of down, 191 00:12:15,100 --> 00:12:19,336 the chicks bide their time waiting for their next meal. 192 00:12:19,336 --> 00:12:22,503 (penguins chattering) 193 00:12:24,990 --> 00:12:27,950 When their parents are away, the chicks form 194 00:12:27,950 --> 00:12:30,683 tight creches to deter predators. 195 00:12:31,900 --> 00:12:35,423 This is the Antarctic equivalent of a daycare center, 196 00:12:36,810 --> 00:12:38,540 complete with guardian adults 197 00:12:38,540 --> 00:12:41,117 making sure wandering youngsters stay put. 198 00:12:50,710 --> 00:12:53,420 A freshly returned adult with a beak full of food 199 00:12:53,420 --> 00:12:57,815 is always welcomed, at times a little too heartily. 200 00:12:57,815 --> 00:13:00,860 (lively music) 201 00:13:00,860 --> 00:13:04,490 It's difficult to distinguish one Adelie chick from another, 202 00:13:04,490 --> 00:13:06,143 even for an Adelie parent. 203 00:13:12,000 --> 00:13:15,530 To ensure it's feeding the right chick, their own, 204 00:13:15,530 --> 00:13:18,843 an adult fending off a feeding horde will move backwards. 205 00:13:22,130 --> 00:13:25,210 Usually the impostor will back away. 206 00:13:25,210 --> 00:13:27,590 Sometimes a parent knows best 207 00:13:27,590 --> 00:13:29,463 and will berate the unrelated chick. 208 00:13:33,671 --> 00:13:37,243 At other times, it's just too difficult to tell. 209 00:13:39,460 --> 00:13:41,480 Running away entirely from the hungry mouths 210 00:13:41,480 --> 00:13:43,383 is simply the easiest option. 211 00:13:45,918 --> 00:13:48,751 (inspiring music) 212 00:13:52,285 --> 00:13:55,130 As summer darkens and daylight hours dwindle, 213 00:13:55,130 --> 00:13:56,650 the falling temperatures signal 214 00:13:56,650 --> 00:13:58,633 it's time for the Adelies to move on. 215 00:14:03,810 --> 00:14:05,430 The brown feathers of the youngsters 216 00:14:05,430 --> 00:14:08,180 are replaced with the highly waterproof feathers 217 00:14:08,180 --> 00:14:09,720 these birds will need to explore 218 00:14:09,720 --> 00:14:13,815 the environment they were born to live in: the sea. 219 00:14:13,815 --> 00:14:16,982 (penguins chattering) 220 00:14:22,550 --> 00:14:25,040 After just seven weeks, the fledglings 221 00:14:25,040 --> 00:14:27,650 are cautiously ready to join their colony 222 00:14:27,650 --> 00:14:29,793 as they return to the ocean. 223 00:14:31,550 --> 00:14:35,100 Their wings cannot fly, they've evolved to be short, 224 00:14:35,100 --> 00:14:37,700 strong, and heavy to help propel them 225 00:14:37,700 --> 00:14:41,180 through the water at speeds of up to 15 kilometers an hour. 226 00:14:46,670 --> 00:14:50,090 It only takes a couple to brave the first plunge 227 00:14:50,090 --> 00:14:52,263 before hundreds follow in a dense pack. 228 00:14:54,550 --> 00:14:57,230 They porpoise out toward the horizon, 229 00:14:57,230 --> 00:14:59,920 leaping dolphin-like to take in air, 230 00:14:59,920 --> 00:15:02,563 pacing themselves for the long voyage ahead. 231 00:15:04,930 --> 00:15:07,280 Over the winter the Adelies will travel 232 00:15:07,280 --> 00:15:09,850 hundreds of kilometers from the continent, 233 00:15:09,850 --> 00:15:13,570 following open water, hunting fish and squid, 234 00:15:13,570 --> 00:15:15,343 and resting on bergs. 235 00:15:18,420 --> 00:15:21,240 They'll become part of an entire food web, 236 00:15:21,240 --> 00:15:24,623 following a course set by the currents. 237 00:15:28,750 --> 00:15:31,950 The current that circumnavigates the Antarctic continent 238 00:15:31,950 --> 00:15:35,160 is the planet's strongest for several reasons, 239 00:15:35,160 --> 00:15:39,620 but a significant one is that it can form a complete circle. 240 00:15:39,620 --> 00:15:41,793 It isn't diverted by a landmass. 241 00:15:43,530 --> 00:15:47,010 This became possible some 30 million years ago 242 00:15:47,010 --> 00:15:50,450 when it finally separated from all other continents, 243 00:15:50,450 --> 00:15:53,893 the last being the southernmost point of Australia. 244 00:15:55,900 --> 00:15:58,430 The island of Tasmania is now more 245 00:15:58,430 --> 00:16:00,890 than 3,000 kilometers away, 246 00:16:00,890 --> 00:16:02,680 and roaring westerly through the strait 247 00:16:02,680 --> 00:16:05,383 that separates the two accelerates the current. 248 00:16:06,260 --> 00:16:09,260 In fact, Australia's small southern island 249 00:16:09,260 --> 00:16:12,809 is the meeting point for four major ocean currents: 250 00:16:12,809 --> 00:16:15,920 (serene music) 251 00:16:15,920 --> 00:16:18,103 the Antarctic Circumpolar Current, 252 00:16:20,890 --> 00:16:22,910 the East Australian Current, 253 00:16:22,910 --> 00:16:25,110 it rounds the cape and heads westward, 254 00:16:25,110 --> 00:16:27,370 becoming the Flinders Current. 255 00:16:27,370 --> 00:16:30,803 Another, the Leeuwin, also arrives from that direction. 256 00:16:33,600 --> 00:16:35,700 This unusual convergence of so many 257 00:16:35,700 --> 00:16:38,820 warm and freezing waters has created 258 00:16:38,820 --> 00:16:41,740 an astonishingly unique marine environment 259 00:16:41,740 --> 00:16:43,753 and helped to shape the land above. 260 00:16:46,160 --> 00:16:49,090 The island of Tasmania became separated 261 00:16:49,090 --> 00:16:53,193 from mainland Australia around 85 million years ago. 262 00:16:55,800 --> 00:16:57,870 Its vegetation includes some of the most 263 00:16:57,870 --> 00:17:00,103 ancient plant species on Earth. 264 00:17:04,640 --> 00:17:06,880 Large tracts of cool-temperate rainforest 265 00:17:06,880 --> 00:17:08,703 cover 10% of the island. 266 00:17:12,100 --> 00:17:15,020 It once shared rainforest with the southern continents, 267 00:17:15,020 --> 00:17:18,063 Africa, South America, and Antarctica. 268 00:17:20,840 --> 00:17:22,750 Plant fossils of these forests 269 00:17:22,750 --> 00:17:24,037 can even be found within sandstones 270 00:17:24,037 --> 00:17:27,163 and mudstones in the Antarctic today. 271 00:17:29,970 --> 00:17:32,560 Tasmania's isolation as an island 272 00:17:32,560 --> 00:17:35,210 has meant fewer introduced predators 273 00:17:35,210 --> 00:17:38,373 and allowed lineages of animal species to continue, 274 00:17:39,320 --> 00:17:40,800 including the world's largest 275 00:17:40,800 --> 00:17:42,673 surviving carnivorous marsupial. 276 00:17:43,762 --> 00:17:45,270 (Tasmanian devil groans) 277 00:17:45,270 --> 00:17:48,190 The Tasmanian devil died out on the mainland 278 00:17:48,190 --> 00:17:53,190 some 3,000 years ago, long before European settlers arrived, 279 00:17:53,690 --> 00:17:57,963 but still lives in the dry eucalypt forests of this island. 280 00:18:00,090 --> 00:18:02,170 Another of Tasmania's unique forests 281 00:18:02,170 --> 00:18:03,873 is more difficult to access. 282 00:18:05,150 --> 00:18:06,996 It's well below the waterline. 283 00:18:06,996 --> 00:18:09,996 (inquisitive music) 284 00:18:11,260 --> 00:18:14,380 The cold ocean off Tasmania's east coast 285 00:18:14,380 --> 00:18:16,693 grows vast tracts of giant kelp forest. 286 00:18:21,420 --> 00:18:23,540 Kelp is a type of seaweed, 287 00:18:23,540 --> 00:18:25,770 and in the cold, nutrient-rich waters 288 00:18:25,770 --> 00:18:28,380 where the southern and northern currents collide, 289 00:18:28,380 --> 00:18:30,683 grows the biggest kelp in the world. 290 00:18:32,510 --> 00:18:35,770 Giant kelp reaches more than 30 meters in height 291 00:18:35,770 --> 00:18:38,420 and grows at an extraordinary rate, 292 00:18:38,420 --> 00:18:40,373 up to half a meter a day. 293 00:18:41,980 --> 00:18:43,500 The long plants are kept afloat 294 00:18:43,500 --> 00:18:47,343 with small, gas-filled bulbs called pneumatocysts. 295 00:18:49,860 --> 00:18:53,430 Like all seaweed, they don't sink roots into the seabed, 296 00:18:53,430 --> 00:18:55,353 but anchor on rock and reef. 297 00:18:57,370 --> 00:19:00,020 In these cool climes, the algae and coral 298 00:19:00,020 --> 00:19:03,363 are deep yellow, rusty reds, and brown. 299 00:19:04,540 --> 00:19:07,150 The dense forests create plenty of hiding spaces 300 00:19:07,150 --> 00:19:10,133 and respite from the strong offshore currents, 301 00:19:11,170 --> 00:19:13,920 and like most macroalgae gardens, 302 00:19:13,920 --> 00:19:17,103 kelp forests have an accomplished resident mimic: 303 00:19:18,623 --> 00:19:21,830 (inquisitive music) 304 00:19:21,830 --> 00:19:23,463 the weedy seadragon. 305 00:19:24,710 --> 00:19:27,280 A distant relative of the seahorse, 306 00:19:27,280 --> 00:19:29,890 this elongated fish has a long snout 307 00:19:29,890 --> 00:19:32,043 to suck up tiny shrimp for feeding. 308 00:19:34,310 --> 00:19:37,960 It's covered in hard, bony plates rather than scales, 309 00:19:37,960 --> 00:19:39,403 which does limit mobility. 310 00:19:41,669 --> 00:19:44,500 The only way the seadragon can propel forward 311 00:19:44,500 --> 00:19:47,193 is by rapidly flickering its tiny abdominal fins. 312 00:19:51,950 --> 00:19:55,883 The slow, undulating pace works in this fish's favor. 313 00:19:58,290 --> 00:20:01,263 The movements echo the gentle sway of kelp in current, 314 00:20:02,350 --> 00:20:04,520 and it's grown additional features 315 00:20:04,520 --> 00:20:06,303 to polish the mimicry act. 316 00:20:08,090 --> 00:20:09,910 Elaborate, leaf-like appendages 317 00:20:09,910 --> 00:20:12,563 extend from the head, body, and tail. 318 00:20:15,860 --> 00:20:17,490 The camouflage is so effective 319 00:20:17,490 --> 00:20:19,350 that once a weedy seadragon reaches 320 00:20:19,350 --> 00:20:22,460 its full adult size of 40 centimeters, 321 00:20:22,460 --> 00:20:24,410 it's rarely eaten by natural predators. 322 00:20:31,802 --> 00:20:34,802 (inquisitive music) 323 00:20:37,260 --> 00:20:39,610 The red velvet fish also relies 324 00:20:39,610 --> 00:20:41,573 on mimicry to avoid being eaten. 325 00:20:42,460 --> 00:20:46,103 It too is only found in these cold South Australian climes. 326 00:20:48,750 --> 00:20:50,970 The velvet fish's fins fan and sway 327 00:20:50,970 --> 00:20:52,980 like the seaweed around it, 328 00:20:52,980 --> 00:20:55,560 and although it's not the strongest swimmer, 329 00:20:55,560 --> 00:20:58,390 this fish will drop to the nearest plant 330 00:20:58,390 --> 00:21:00,483 and begin its best imitation. 331 00:21:02,720 --> 00:21:05,680 If the ruse doesn't work, its spines can deliver 332 00:21:05,680 --> 00:21:07,833 a powerful shot of toxic venom. 333 00:21:13,323 --> 00:21:16,323 (inquisitive music) 334 00:21:17,670 --> 00:21:20,710 Near the kelp forest but in deeper water, 335 00:21:20,710 --> 00:21:23,203 sponge gardens claim the rock faces. 336 00:21:25,040 --> 00:21:28,810 Sponges are one of the most ancient lifeforms on Earth, 337 00:21:28,810 --> 00:21:30,740 with fossils of ancestors dating back 338 00:21:30,740 --> 00:21:33,363 more than 600 million years. 339 00:21:36,920 --> 00:21:39,320 In Tasmanian waters today, 340 00:21:39,320 --> 00:21:42,193 they rely on the ocean currents to bring them food. 341 00:21:45,190 --> 00:21:48,030 Unlike hard corals, these animals 342 00:21:48,030 --> 00:21:51,073 don't harbor algae that photosynthesize sunlight. 343 00:21:52,500 --> 00:21:55,400 Instead, these sponges and sea whips 344 00:21:55,400 --> 00:22:00,400 flourish in depths past 30 meters, beyond the sun's rays, 345 00:22:00,420 --> 00:22:02,623 filtering nutrients as they float by. 346 00:22:07,330 --> 00:22:10,053 Other animals take shelter by day in the depths. 347 00:22:16,860 --> 00:22:19,710 Some, like this cold water southern rock lobster 348 00:22:19,710 --> 00:22:23,653 ascend to the kelp forests nightly on foraging excursions. 349 00:22:26,270 --> 00:22:29,553 Cold water anemones also unfurl to feed at dusk. 350 00:22:30,520 --> 00:22:33,480 Closely related to coral polyps and jellyfish, 351 00:22:33,480 --> 00:22:36,970 these are animals that attach to a hard surface with a foot, 352 00:22:36,970 --> 00:22:39,550 and have stinging tentacles to catch food 353 00:22:39,550 --> 00:22:42,063 and pass down to a central mouth and gut. 354 00:22:43,700 --> 00:22:47,160 This swimming anemone attaches to rocks but will often move 355 00:22:47,160 --> 00:22:49,600 to the end of kelp fronds after sundown 356 00:22:49,600 --> 00:22:51,950 to get in better range of the passing plankton. 357 00:22:55,870 --> 00:22:58,530 A smooth ray glides up from the sea bed 358 00:22:58,530 --> 00:23:00,983 and leaves a trail of sand over the kelp. 359 00:23:02,410 --> 00:23:05,970 This is the largest stingray in the world, 360 00:23:05,970 --> 00:23:09,460 but only uses the barb on its tail in defense. 361 00:23:09,460 --> 00:23:13,263 To eat, it smothers and crushes shrimp and crabs. 362 00:23:14,360 --> 00:23:18,340 As winter approaches, the smooth ray heads north 363 00:23:18,340 --> 00:23:21,693 where an astonishing crab feast is about to come on offer. 364 00:23:23,890 --> 00:23:26,220 The Great Australian Bight is bordered 365 00:23:26,220 --> 00:23:29,100 by the Southern Ocean and the powerful force 366 00:23:29,100 --> 00:23:31,463 of the Antarctic Circumpolar Current. 367 00:23:32,750 --> 00:23:34,320 Along the continent shelf, 368 00:23:34,320 --> 00:23:36,423 a westward current called the Flinders, 369 00:23:37,440 --> 00:23:39,400 a surface current called the Leeuwin, 370 00:23:39,400 --> 00:23:42,741 travels eastward seasonally from the Indian Ocean. 371 00:23:42,741 --> 00:23:45,720 (inspirational music) 372 00:23:45,720 --> 00:23:49,930 These currents and countercurrents create upwellings, 373 00:23:49,930 --> 00:23:53,863 a process where deep, cold water rises to the surface. 374 00:23:54,720 --> 00:23:57,270 It replaces the warm surface water 375 00:23:57,270 --> 00:24:00,550 and brings with it a rush of nutrients. 376 00:24:00,550 --> 00:24:04,730 Single-celled plants called phytoplankton and zooplankton, 377 00:24:04,730 --> 00:24:08,543 animal lifeforms, tiny marine eggs, and larvae. 378 00:24:09,700 --> 00:24:11,980 These are the foundations that allow 379 00:24:11,980 --> 00:24:15,243 entire ecosystems to build and bloom. 380 00:24:16,470 --> 00:24:19,340 Cold water species thrive here, 381 00:24:19,340 --> 00:24:23,183 lobsters and sardines, whales and sharks. 382 00:24:24,560 --> 00:24:26,860 Its proximity to the South Pole 383 00:24:26,860 --> 00:24:29,330 and isolation from other continents 384 00:24:29,330 --> 00:24:33,500 has created spectacular underwater adaptations. 385 00:24:33,500 --> 00:24:36,890 Over 90% of the plants and animals here 386 00:24:36,890 --> 00:24:38,973 are found nowhere else on Earth. 387 00:24:42,710 --> 00:24:45,770 The bight itself is home to enormous bays, 388 00:24:45,770 --> 00:24:47,930 basins that have thousands of kilometers 389 00:24:47,930 --> 00:24:50,363 of rivers and creeks pouring into it. 390 00:24:53,610 --> 00:24:56,010 One such bay is Port Phillip. 391 00:24:56,010 --> 00:24:58,550 It's north of the island of Tasmania 392 00:24:58,550 --> 00:25:00,430 and happens to also be the backyard 393 00:25:00,430 --> 00:25:03,743 of Australia's second largest city, Melbourne. 394 00:25:05,162 --> 00:25:08,162 (inquisitive music) 395 00:25:10,310 --> 00:25:13,150 As the water temperatures drop each winter, 396 00:25:13,150 --> 00:25:15,830 visitors from the cold depths beyond 397 00:25:15,830 --> 00:25:18,890 begin a steady march up the continental shelf 398 00:25:18,890 --> 00:25:20,633 into the shallows of the bay. 399 00:25:22,140 --> 00:25:25,730 Long encased legs move steadily with purpose 400 00:25:25,730 --> 00:25:28,563 towards a central meeting point on the seabed. 401 00:25:33,080 --> 00:25:35,630 These are giant spider crabs, 402 00:25:35,630 --> 00:25:38,273 the largest crustacean on Earth. 403 00:25:39,830 --> 00:25:42,173 They can live to 100 years old. 404 00:25:43,300 --> 00:25:46,393 Each crab has a leg span of nearly half a meter. 405 00:25:47,260 --> 00:25:51,610 Despite its size, a single crab is difficult to spot, 406 00:25:51,610 --> 00:25:54,893 hiding amongst macroalgae and sponge gardens. 407 00:25:56,840 --> 00:26:01,760 But once a year they undertake a massive undersea migration. 408 00:26:01,760 --> 00:26:05,533 They come to Port Phillip Bay in the hundreds of thousands. 409 00:26:11,590 --> 00:26:14,350 The water becomes clouded with sand 410 00:26:14,350 --> 00:26:16,870 as giant spider crabs clamor over each other 411 00:26:16,870 --> 00:26:19,200 without hierarchy or order, 412 00:26:19,200 --> 00:26:21,863 sometimes as many as 10 crabs deep. 413 00:26:25,720 --> 00:26:29,620 They're here for an annual event in their lifecycle, 414 00:26:29,620 --> 00:26:32,723 and it's one that will require safety in numbers. 415 00:26:36,880 --> 00:26:40,000 Giant spider crabs have exoskeleton shells 416 00:26:40,000 --> 00:26:44,240 called carapaces to protect their soft insides. 417 00:26:44,240 --> 00:26:46,723 However, the carapaces don't grow. 418 00:26:49,600 --> 00:26:51,260 The crabs must shed their shells 419 00:26:51,260 --> 00:26:53,493 in a process called molting. 420 00:26:57,120 --> 00:26:59,160 For several weeks prior, it begins 421 00:26:59,160 --> 00:27:01,903 growing a new, soft shell underneath. 422 00:27:04,040 --> 00:27:06,550 A day before the crab is ready to molt, 423 00:27:06,550 --> 00:27:09,523 it absorbs sea water and swells like a balloon. 424 00:27:10,360 --> 00:27:13,070 The shell comes apart at the seams, 425 00:27:13,070 --> 00:27:16,633 the old one popping up like a lid sitting atop. 426 00:27:17,760 --> 00:27:20,263 Then it's time to change. 427 00:27:21,280 --> 00:27:24,010 Over about 20 minutes, the spider crab 428 00:27:24,010 --> 00:27:26,730 pushes backwards on all of its legs 429 00:27:26,730 --> 00:27:29,143 slowly backing out of the shell. 430 00:27:30,610 --> 00:27:34,000 Finally it pulls its long legs free 431 00:27:34,000 --> 00:27:37,043 and it's a new, slightly larger crab. 432 00:27:39,450 --> 00:27:42,363 The old skeleton is left sitting on the sea floor. 433 00:27:44,560 --> 00:27:48,090 The new shell is very soft for a number of days 434 00:27:48,090 --> 00:27:51,360 and it will take a month to fully harden. 435 00:27:51,360 --> 00:27:54,093 Predators know this is a vulnerable time for the crab. 436 00:27:55,983 --> 00:27:58,560 When it comes to molting, safety in numbers 437 00:27:58,560 --> 00:28:00,653 is a necessary survival strategy. 438 00:28:03,030 --> 00:28:06,333 They'll come back to this same place year after year. 439 00:28:10,470 --> 00:28:12,520 When the molting season ends, 440 00:28:12,520 --> 00:28:15,070 it's time to once again head south 441 00:28:15,070 --> 00:28:19,083 to return to a solitary life 300 meters below. 442 00:28:29,380 --> 00:28:32,540 A little further west along the Flinders Current, 443 00:28:32,540 --> 00:28:34,310 the winter calling of the water 444 00:28:34,310 --> 00:28:37,993 heralds the start of another extraordinary migration. 445 00:28:40,250 --> 00:28:43,070 In the upper reaches of the Spencer Gulf, 446 00:28:43,070 --> 00:28:46,440 an enormous catchment for creeks and rivers, 447 00:28:46,440 --> 00:28:48,860 another of the Southern Ocean giants 448 00:28:48,860 --> 00:28:50,654 has come in from the deep. 449 00:28:50,654 --> 00:28:53,600 (serene music) 450 00:28:53,600 --> 00:28:55,700 The giant Australian cuttlefish 451 00:28:55,700 --> 00:28:58,053 is the largest of its kind in the world. 452 00:28:59,300 --> 00:29:02,000 They reach 60 centimeters in length 453 00:29:02,000 --> 00:29:04,063 and weigh up to 10 kilograms. 454 00:29:07,619 --> 00:29:10,840 In a small corner of the gulf is a flat rock ledge 455 00:29:10,840 --> 00:29:13,620 where the water temperature remains fairly constant, 456 00:29:13,620 --> 00:29:16,160 between 12 and 15 degrees. 457 00:29:16,160 --> 00:29:19,743 It's the ideal place for females to deposit their eggs. 458 00:29:23,840 --> 00:29:27,090 It's the only such place for hundreds of kilometers, 459 00:29:27,090 --> 00:29:30,750 and so the oceanic giants come here yearly, 460 00:29:30,750 --> 00:29:33,473 more than 100,000 of them. 461 00:29:35,700 --> 00:29:37,740 This is the densest mass cuttlefish 462 00:29:37,740 --> 00:29:39,203 aggregation in the world. 463 00:29:45,700 --> 00:29:49,680 The male giant cuttlefish are here for one reason, 464 00:29:49,680 --> 00:29:51,363 to impress the females. 465 00:29:52,220 --> 00:29:55,910 The bulls are much larger than the females. 466 00:29:55,910 --> 00:29:58,743 They flash colors to show off their size and health. 467 00:30:01,680 --> 00:30:04,180 (tense music) 468 00:30:05,450 --> 00:30:08,700 When they find a female who seems wiling to mate, 469 00:30:08,700 --> 00:30:10,593 competition is fierce. 470 00:30:12,360 --> 00:30:15,100 A large male bull will guard a female, 471 00:30:15,100 --> 00:30:18,410 hovering over her, hiding her under rock ledges, 472 00:30:18,410 --> 00:30:21,733 and fending off the constant attention of other males. 473 00:30:28,120 --> 00:30:30,600 Scientists refer to these animals 474 00:30:30,600 --> 00:30:33,770 as the rock stars of the marine world. 475 00:30:33,770 --> 00:30:36,660 Closely related to octopus and squid, 476 00:30:36,660 --> 00:30:39,603 cuttlefish live fast and die young. 477 00:30:42,180 --> 00:30:45,150 They only live for 12 to 18 months 478 00:30:45,150 --> 00:30:46,690 and each breeding season is their 479 00:30:46,690 --> 00:30:50,033 one opportunity to continue their genes. 480 00:30:51,140 --> 00:30:54,120 With such high stakes, the bull males 481 00:30:54,120 --> 00:30:57,223 resort to physically blocking access to the females. 482 00:31:02,250 --> 00:31:03,810 The males try their hardest 483 00:31:03,810 --> 00:31:06,600 to get within arm's reach of the females. 484 00:31:06,600 --> 00:31:10,073 One of their tentacles contains a packet of spermatophores. 485 00:31:12,550 --> 00:31:15,560 If the female accepts the male's advances, 486 00:31:15,560 --> 00:31:18,300 he'll need to reach into the cavity of her head 487 00:31:18,300 --> 00:31:20,843 to deposit it into her oviduct. 488 00:31:28,570 --> 00:31:31,533 That's if he can get close enough in the first place. 489 00:31:32,970 --> 00:31:35,250 As well as the large dominant males, 490 00:31:35,250 --> 00:31:37,940 there are smaller males in the water, 491 00:31:37,940 --> 00:31:41,033 and they have their own strategy for mating. 492 00:31:47,830 --> 00:31:49,200 They'll take on the coloration 493 00:31:49,200 --> 00:31:51,833 of a female to seem unimposing. 494 00:31:53,910 --> 00:31:55,300 The small male will then attempt 495 00:31:55,300 --> 00:31:57,770 to sneak past the giant bull guard 496 00:31:57,770 --> 00:32:01,157 and reach the female while the larger males fight it out. 497 00:32:12,170 --> 00:32:16,680 Sometimes it works, but today this small male 498 00:32:16,680 --> 00:32:18,423 has been denied access. 499 00:32:22,780 --> 00:32:26,800 At times the female simply gets fed up. 500 00:32:26,800 --> 00:32:29,660 She makes her escape, leaving the bulls 501 00:32:29,660 --> 00:32:31,433 alone in each other's company. 502 00:32:37,220 --> 00:32:39,660 The males don't have a great success rate, 503 00:32:39,660 --> 00:32:42,850 only one in four attempts. 504 00:32:42,850 --> 00:32:45,820 They continue to flash colors at each other. 505 00:32:45,820 --> 00:32:48,690 This is the cuttlefish equivalent of flexing muscles 506 00:32:48,690 --> 00:32:51,053 and showing they are strong competitors, 507 00:32:58,460 --> 00:33:03,403 and every so often the swoop-in approach is timed perfectly. 508 00:33:06,200 --> 00:33:08,223 A bull male hesitates for a moment. 509 00:33:10,840 --> 00:33:14,120 The female is receptive and accepts, 510 00:33:14,120 --> 00:33:16,527 and a successful mating ensues. 511 00:33:16,527 --> 00:33:19,110 (serene music) 512 00:33:22,100 --> 00:33:23,660 The giant cuttlefish will attempt 513 00:33:23,660 --> 00:33:25,470 as many couplings as they can 514 00:33:25,470 --> 00:33:28,123 in this one short window of time they have. 515 00:33:31,590 --> 00:33:33,397 If they are lucky, they may survive 516 00:33:33,397 --> 00:33:35,423 to see another breeding season, 517 00:33:36,520 --> 00:33:40,020 but most of these giants will die off at winter's end, 518 00:33:40,020 --> 00:33:41,790 not long after they have retreated 519 00:33:41,790 --> 00:33:44,773 back to the deeper water of the Southern Ocean. 520 00:33:48,840 --> 00:33:50,640 The area where the cold waters 521 00:33:50,640 --> 00:33:52,910 of the Antarctic Circumpolar Current 522 00:33:52,910 --> 00:33:55,340 mingle with the warmer waters of the north 523 00:33:55,340 --> 00:33:58,490 is known as the Antarctic Convergence. 524 00:33:58,490 --> 00:34:01,350 Here a higher concentration of nutrients 525 00:34:01,350 --> 00:34:03,741 means a great abundance of marine life. 526 00:34:03,741 --> 00:34:06,960 (spirited music) 527 00:34:06,960 --> 00:34:11,560 Prion Island is a tiny outcrop that sits on the convergence, 528 00:34:11,560 --> 00:34:13,890 midway between mainland South America 529 00:34:13,890 --> 00:34:15,993 and the tip of the Antarctic continent. 530 00:34:18,410 --> 00:34:21,090 Just under 2.5 kilometers long, 531 00:34:21,090 --> 00:34:23,100 this rocky island is one of the world's 532 00:34:23,100 --> 00:34:27,263 most important sanctuaries for seabirds and seals. 533 00:34:31,150 --> 00:34:33,750 In the southern summer, temperatures rise 534 00:34:33,750 --> 00:34:36,390 to a couple of degrees below zero 535 00:34:36,390 --> 00:34:39,323 and Prion Island becomes almost ice-free. 536 00:34:40,350 --> 00:34:43,103 Thick tufts of grass burst through the snow. 537 00:34:44,640 --> 00:34:46,950 Unlike most Antarctic islands visited 538 00:34:46,950 --> 00:34:48,900 by whaling ships in the past, 539 00:34:48,900 --> 00:34:51,343 Prion Island remains free of rats. 540 00:34:53,170 --> 00:34:56,060 That means eggs are save from the ubiquitous vermin 541 00:34:56,960 --> 00:35:00,593 and the seabird population has flourished here as a result. 542 00:35:03,130 --> 00:35:06,730 Prion Island is one of the few places you can see 543 00:35:06,730 --> 00:35:10,563 the world's largest flying bird return to land, 544 00:35:11,960 --> 00:35:13,883 the wandering albatross. 545 00:35:15,630 --> 00:35:18,190 Albatross are renowned for their size 546 00:35:18,190 --> 00:35:20,853 and this is the biggest of its kind. 547 00:35:21,810 --> 00:35:25,040 The wanderer weighs up to 12 kilograms 548 00:35:25,040 --> 00:35:29,103 and has a wingspan of three meters from tip to tip. 549 00:35:30,330 --> 00:35:35,193 Wandering albatross are the most oceanic of all seabirds. 550 00:35:37,110 --> 00:35:39,970 They can coast for several hundred kilometers 551 00:35:39,970 --> 00:35:42,073 without a single wing flap. 552 00:35:43,230 --> 00:35:46,130 The albatross do this utilizing the winds 553 00:35:46,130 --> 00:35:49,223 generated above the Antarctic Circumpolar Current. 554 00:35:50,070 --> 00:35:52,780 They spend most of their lives in the air, 555 00:35:52,780 --> 00:35:54,983 following it around the southern continent. 556 00:35:57,920 --> 00:36:01,100 Wanderers don't come ashore until they're ready to breed 557 00:36:01,100 --> 00:36:03,253 at around five to 10 years of age. 558 00:36:07,170 --> 00:36:10,210 Each summer the central plateau of Prion Island 559 00:36:10,210 --> 00:36:13,333 becomes the stage for a season of courting. 560 00:36:14,930 --> 00:36:16,870 It's important a wandering albatross 561 00:36:16,870 --> 00:36:20,423 takes the time to size up and settle on a good match. 562 00:36:23,280 --> 00:36:26,670 The partner they leave the island with at the end of summer 563 00:36:26,670 --> 00:36:30,723 will be their mate for life, some 50 years. 564 00:36:33,290 --> 00:36:36,230 Females usually initiate the meetings, 565 00:36:36,230 --> 00:36:39,183 which lead to a long, intricate ritual. 566 00:36:39,183 --> 00:36:42,016 (uplifting music) 567 00:36:43,950 --> 00:36:46,513 It begins with a clacking of beaks, 568 00:36:49,990 --> 00:36:52,960 bouts of preening, and a noise 569 00:36:52,960 --> 00:36:55,043 that almost sounds like a throaty purr. 570 00:36:55,928 --> 00:36:58,928 (albatross purring) 571 00:37:02,620 --> 00:37:05,340 It soon progresses to a dance. 572 00:37:05,340 --> 00:37:08,340 For minutes, sometimes hours, at a time, 573 00:37:08,340 --> 00:37:09,850 these birds will circle each other 574 00:37:09,850 --> 00:37:12,750 with wings fully extended, showing off 575 00:37:12,750 --> 00:37:15,523 the impressive full gamut of their greatest asset. 576 00:37:18,010 --> 00:37:20,000 About a quarter of the time, 577 00:37:20,000 --> 00:37:23,993 the dance ends with the female and male nesting together. 578 00:37:26,030 --> 00:37:28,563 However, it's a long summer. 579 00:37:30,110 --> 00:37:34,338 Although wanderers pair for life, they are not monogamous. 580 00:37:34,338 --> 00:37:36,900 (albatross purring) 581 00:37:36,900 --> 00:37:41,830 At times courting pairs divert their attention to others. 582 00:37:41,830 --> 00:37:45,373 It's not unusual for a third albatross to join the dance. 583 00:37:46,618 --> 00:37:49,785 (albatrosses calling) 584 00:37:50,820 --> 00:37:53,850 Females will often mate with multiple partners 585 00:37:53,850 --> 00:37:56,380 and produce eggs sired by a mix of fathers 586 00:37:56,380 --> 00:37:57,773 over their lifetimes. 587 00:38:00,030 --> 00:38:03,223 It's a way of maximizing a very limited breeding pattern. 588 00:38:04,130 --> 00:38:07,113 The wanderers lay just one egg every two years. 589 00:38:08,660 --> 00:38:10,580 Their chosen life partner will help 590 00:38:10,580 --> 00:38:13,743 incubate the egg regardless of paternity. 591 00:38:16,770 --> 00:38:19,280 The albatross chicks remain on Prion Island 592 00:38:19,280 --> 00:38:22,310 for about nine months, strengthening their wings 593 00:38:22,310 --> 00:38:24,923 in preparation for the long journey ahead. 594 00:38:28,500 --> 00:38:30,460 When they leave, they'll have attained 595 00:38:30,460 --> 00:38:33,023 the full length of their remarkable wingspan. 596 00:38:34,090 --> 00:38:37,793 The young wanderers will remain at sea alone for years. 597 00:38:40,170 --> 00:38:42,690 They'll drink salt water for hydration, 598 00:38:42,690 --> 00:38:45,823 fish from the air, and follow the polar currents. 599 00:38:49,860 --> 00:38:53,490 It will be nearly a decade before they return to Prion 600 00:38:53,490 --> 00:38:55,680 to find their own mate to spend 601 00:38:55,680 --> 00:38:58,280 the remainder of their lives wandering with. 602 00:39:02,655 --> 00:39:06,490 (intriguing music) (seal chirping) 603 00:39:06,490 --> 00:39:10,470 Below this hills on Prion Island's only shingle beach, 604 00:39:10,470 --> 00:39:12,840 another breeding seeding gets underway 605 00:39:12,840 --> 00:39:14,213 with the start of summer. 606 00:39:16,460 --> 00:39:19,893 Antarctic fur seals are the smallest of the seal family. 607 00:39:23,150 --> 00:39:24,710 Rather than relying on a generous 608 00:39:24,710 --> 00:39:27,000 inner tubing of fat for warmth, 609 00:39:27,000 --> 00:39:30,213 these seals are covered in very thick brown fur. 610 00:39:33,860 --> 00:39:36,870 Females usually weigh about 40 kilograms, 611 00:39:36,870 --> 00:39:39,203 but the big males can weigh up to 200. 612 00:39:41,706 --> 00:39:43,280 (seals squealing) 613 00:39:43,280 --> 00:39:46,393 These large bulls are usually first to the beach. 614 00:39:48,330 --> 00:39:51,130 They have to find the most inviting areas 615 00:39:51,130 --> 00:39:52,913 and establish their territory. 616 00:39:55,640 --> 00:40:00,060 In places further north, fur seal bulls fight one another 617 00:40:00,060 --> 00:40:01,640 to establish their right to groups 618 00:40:01,640 --> 00:40:03,943 of breeding females called harems. 619 00:40:06,230 --> 00:40:10,223 On Prion Island, the beach is a relatively small space. 620 00:40:11,480 --> 00:40:14,350 The females move about more freely, 621 00:40:14,350 --> 00:40:18,670 but the males will try to herd them into their territories. 622 00:40:18,670 --> 00:40:22,193 Once there, they will try to block them from leaving. 623 00:40:23,308 --> 00:40:27,420 (seal squeals) (somber music) 624 00:40:27,420 --> 00:40:30,140 More than three times the female's size 625 00:40:30,140 --> 00:40:32,100 and full of testosterone, 626 00:40:32,100 --> 00:40:35,233 this bull is too difficult to negotiate a path around. 627 00:40:39,050 --> 00:40:42,533 The female fur seal collapses from sheer exhaustion. 628 00:40:43,520 --> 00:40:46,460 She needs a rest before trying again 629 00:40:46,460 --> 00:40:48,260 in hope the bull's attention 630 00:40:48,260 --> 00:40:50,283 will soon be diverted elsewhere. 631 00:40:56,390 --> 00:40:59,283 For some females, the attention is relentless. 632 00:41:00,550 --> 00:41:02,910 A prized female may have a number of bulls 633 00:41:02,910 --> 00:41:04,610 clashing while trying to herd her. 634 00:41:08,240 --> 00:41:11,400 The males are so determined to defend their domain 635 00:41:11,400 --> 00:41:15,070 some won't even eat for several weeks. 636 00:41:15,070 --> 00:41:17,210 Feeding means a return to the ocean, 637 00:41:17,210 --> 00:41:18,540 and they'd rather starve 638 00:41:18,540 --> 00:41:21,103 than relinquish their hard-won territory. 639 00:41:24,215 --> 00:41:26,370 (baby seal whimpering) 640 00:41:26,370 --> 00:41:29,290 Many of the females arrive on Prion's beach 641 00:41:29,290 --> 00:41:32,473 already pregnant from the previous breeding season. 642 00:41:33,400 --> 00:41:36,350 The summer begins with a series of births, 643 00:41:36,350 --> 00:41:39,920 freeing the females to mate again soon after. 644 00:41:39,920 --> 00:41:42,663 But first a newborn needs attention. 645 00:41:43,530 --> 00:41:46,660 The small pups are very vulnerable in their first hours 646 00:41:46,660 --> 00:41:49,410 before they've learned to walk on their front flippers. 647 00:41:51,690 --> 00:41:54,293 Mother and pup bond through nuzzling and vocalizing. 648 00:41:55,390 --> 00:41:58,307 (seals chattering) 649 00:42:02,800 --> 00:42:04,503 This pup needs to nurse. 650 00:42:05,780 --> 00:42:08,270 Exhausted, the mother rolls on her back 651 00:42:08,270 --> 00:42:09,840 to help show the way. 652 00:42:09,840 --> 00:42:12,757 (seals chattering) 653 00:42:16,720 --> 00:42:19,440 After a week, the pup will be left on the beach 654 00:42:19,440 --> 00:42:22,130 alone for hours at a time. 655 00:42:22,130 --> 00:42:25,599 The mothers must return to the sea to feed on krill. 656 00:42:25,599 --> 00:42:28,682 (lighthearted music) 657 00:42:31,083 --> 00:42:34,166 (baby seal chirping) 658 00:42:37,570 --> 00:42:40,730 The next four months are a demanding time for these mothers. 659 00:42:40,730 --> 00:42:43,130 They continue a cycle of weaning, feeding, 660 00:42:43,130 --> 00:42:46,219 and mating in between pup rearing. 661 00:42:46,219 --> 00:42:49,136 (seals chattering) 662 00:42:51,190 --> 00:42:53,380 The pups put on weight quickly. 663 00:42:53,380 --> 00:42:56,883 The first snow will signal it's time to leave the island. 664 00:42:58,370 --> 00:43:00,880 At summer's end, these fledgling fur seals 665 00:43:00,880 --> 00:43:04,023 will take their first plunge into the Antarctic Ocean. 666 00:43:06,340 --> 00:43:08,650 It will be many years before they return to this beach 667 00:43:08,650 --> 00:43:11,693 to begin the cycle anew as breeding adults. 668 00:43:19,450 --> 00:43:21,720 Beyond the Antarctic Convergence, 669 00:43:21,720 --> 00:43:24,150 Drake's Passage is the narrowest squeeze point 670 00:43:24,150 --> 00:43:25,793 for the Circumpolar Current. 671 00:43:27,380 --> 00:43:29,140 It's just 800 kilometers between 672 00:43:29,140 --> 00:43:32,449 the continents of Antarctica and South America. 673 00:43:32,449 --> 00:43:35,032 (serene music) 674 00:43:38,890 --> 00:43:41,440 Argentina's incredibly diverse terrain 675 00:43:41,440 --> 00:43:46,440 hosts equally unique species, from the Andean condor 676 00:43:46,640 --> 00:43:50,893 to guanacos, close relatives of llamas and camels. 677 00:43:53,210 --> 00:43:55,610 But the icy fingers of polar currents 678 00:43:55,610 --> 00:43:58,650 reach far along the Argentinian coastline, 679 00:43:58,650 --> 00:44:01,983 courtesy of the Malvinas or Falklands Current. 680 00:44:03,440 --> 00:44:06,200 It flows north along the Atlantic coast 681 00:44:06,200 --> 00:44:09,063 and meets a warmer current coming south from Brazil. 682 00:44:10,010 --> 00:44:13,870 Southern species travel the cold path to this hot spot, 683 00:44:13,870 --> 00:44:15,773 following nutrients in the summer. 684 00:44:17,210 --> 00:44:19,820 Peninsula Valdes juts out from the mainland 685 00:44:19,820 --> 00:44:21,913 more than 100 kilometers eastward. 686 00:44:25,340 --> 00:44:27,070 The mushroom-shaped peninsula 687 00:44:27,070 --> 00:44:29,570 has large gulfs that offer shelter 688 00:44:29,570 --> 00:44:32,803 from the harsh wind and large waves of the South Atlantic. 689 00:44:36,610 --> 00:44:38,650 These protected areas have become 690 00:44:38,650 --> 00:44:42,323 huge maternity wards for cold water animals. 691 00:44:44,040 --> 00:44:47,910 The shores are thick with breeding colonies of seabirds, 692 00:44:47,910 --> 00:44:50,310 like migratory snowy sheathbills 693 00:44:50,310 --> 00:44:51,883 and resident steamer ducks. 694 00:44:55,620 --> 00:44:58,350 It's home to tens of thousands of South America's 695 00:44:58,350 --> 00:45:01,423 own burrowing penguin, the Magellanic. 696 00:45:05,060 --> 00:45:06,720 Southern right whales stop over 697 00:45:06,720 --> 00:45:10,213 in the bay's north and south to breed and calf. 698 00:45:14,290 --> 00:45:16,330 Peninsula Valdes beaches are dark 699 00:45:16,330 --> 00:45:19,083 with sand and silt from nearby mudflats. 700 00:45:20,052 --> 00:45:23,210 (inquisitive music) 701 00:45:23,210 --> 00:45:26,810 Each summer around 20,000 southern elephant seals 702 00:45:26,810 --> 00:45:29,340 come ashore to mate, give birth, 703 00:45:29,340 --> 00:45:32,223 and strengthen their young before returning to the sea. 704 00:45:34,720 --> 00:45:36,380 By late December they're joined 705 00:45:36,380 --> 00:45:39,581 by large colonies of Patagonian sea lions. 706 00:45:39,581 --> 00:45:41,570 (sea lions chattering) 707 00:45:41,570 --> 00:45:42,980 The sea lions are also here 708 00:45:42,980 --> 00:45:44,943 to raise their pups on the beaches. 709 00:45:47,870 --> 00:45:50,840 Sea lions have stronger front flippers than seals. 710 00:45:50,840 --> 00:45:52,983 They walk on all fours on the beach. 711 00:45:57,690 --> 00:46:01,293 Seals have strong back flippers and wriggle about on land. 712 00:46:03,100 --> 00:46:05,490 Unlike the elephant seal mothers, 713 00:46:05,490 --> 00:46:08,370 the female sea lions will keep entering the sea 714 00:46:08,370 --> 00:46:10,160 to hunt small fish and squid 715 00:46:10,160 --> 00:46:12,243 while their young are still nursing. 716 00:46:16,330 --> 00:46:19,113 The sea lion pups wait in the shore break. 717 00:46:20,730 --> 00:46:23,610 They take their first dips into the salt water, 718 00:46:23,610 --> 00:46:24,910 strengthening their flippers 719 00:46:24,910 --> 00:46:26,833 with practice swims in the shallows. 720 00:46:30,640 --> 00:46:32,550 But another marine mammal also 721 00:46:32,550 --> 00:46:34,673 brings their young to these coastlines. 722 00:46:35,570 --> 00:46:38,080 They know the pups are vulnerable 723 00:46:38,080 --> 00:46:40,621 and this is an easy place to hunt. 724 00:46:40,621 --> 00:46:43,121 (tense music) 725 00:46:46,200 --> 00:46:49,260 Orcas are the ultimate ocean predator. 726 00:46:49,260 --> 00:46:51,110 Highly intelligent, they have 727 00:46:51,110 --> 00:46:53,453 sophisticated pack hunting techniques. 728 00:46:54,370 --> 00:46:55,810 They're the only marine animals 729 00:46:55,810 --> 00:46:58,483 known to kill and eat great white sharks. 730 00:47:01,120 --> 00:47:03,200 On these Argentinian beaches, 731 00:47:03,200 --> 00:47:05,393 their targets are much smaller. 732 00:47:07,220 --> 00:47:09,330 The sea lion pups are only just learning 733 00:47:09,330 --> 00:47:11,330 to venture into the water, 734 00:47:11,330 --> 00:47:15,151 and are not yet aware of the enormous danger within it, 735 00:47:15,151 --> 00:47:17,890 or the fact that this particular danger 736 00:47:17,890 --> 00:47:20,963 has the ability to lunge out. 737 00:47:28,042 --> 00:47:30,292 Orcas have been hunting this beach for years. 738 00:47:31,200 --> 00:47:33,560 They know where the channels are in the shallows 739 00:47:33,560 --> 00:47:35,460 that will grant them just enough depth 740 00:47:35,460 --> 00:47:38,763 to surge and push forward onto the beach. 741 00:47:40,720 --> 00:47:44,170 This is a massive six ton animal. 742 00:47:44,170 --> 00:47:46,640 When it throws its heavy body ashore, 743 00:47:46,640 --> 00:47:48,380 the orca then has to thrash about 744 00:47:48,380 --> 00:47:50,753 and inch itself back into the deep. 745 00:47:57,570 --> 00:47:59,800 The whales watch the juvenile sea lions 746 00:47:59,800 --> 00:48:03,363 from the deeper drop off and time their ambush. 747 00:48:09,370 --> 00:48:13,150 This one misses, but incredibly the sea lion pup 748 00:48:13,150 --> 00:48:15,683 turns around and heads straight back into the sea. 749 00:48:16,630 --> 00:48:18,180 It's been practicing swimming enough 750 00:48:18,180 --> 00:48:20,293 to be faster in water than on land. 751 00:48:23,600 --> 00:48:26,720 It tries to reach the protection of adults 752 00:48:26,720 --> 00:48:28,550 but the pup has to stay shallow enough 753 00:48:28,550 --> 00:48:30,363 to avoid a second attack. 754 00:48:34,230 --> 00:48:35,730 The water is still too shallow 755 00:48:35,730 --> 00:48:38,033 for the huge mammal to get an accurate launch. 756 00:48:39,350 --> 00:48:42,430 It misses once again and this time, 757 00:48:42,430 --> 00:48:44,153 the pup heads straight for land. 758 00:48:47,750 --> 00:48:50,350 However these orcas need to catch and eat 759 00:48:50,350 --> 00:48:52,550 about three sea lion pups a day 760 00:48:52,550 --> 00:48:55,853 to get enough fuel to sustain their massive bodies. 761 00:48:58,040 --> 00:48:59,823 They know this shoreline well. 762 00:49:01,910 --> 00:49:05,510 When a small group of pups catches a small shore break in, 763 00:49:05,510 --> 00:49:06,980 they realize too late. 764 00:49:06,980 --> 00:49:09,623 The next wave comes with a massive dorsal fin. 765 00:49:10,680 --> 00:49:13,963 The orca grasps its catch with small conical teeth. 766 00:49:16,070 --> 00:49:18,393 Others nearby soon join the hunt. 767 00:49:24,767 --> 00:49:27,530 The orcas here at Peninsula Valdes 768 00:49:27,530 --> 00:49:28,610 are thought to have passed this 769 00:49:28,610 --> 00:49:30,230 particular beach attack technique 770 00:49:30,230 --> 00:49:32,803 down to their young for generations. 771 00:49:35,630 --> 00:49:37,670 Around the world orca will 772 00:49:37,670 --> 00:49:40,203 target prey specific to locations. 773 00:49:41,080 --> 00:49:44,090 Family groups adapt new hunting methods accordingly 774 00:49:44,090 --> 00:49:46,090 and pass those onto their young as well. 775 00:49:48,060 --> 00:49:51,420 It's thought in this way unique cultures are formed 776 00:49:51,420 --> 00:49:53,802 depending on where the orcas live. 777 00:49:53,802 --> 00:49:56,500 (inquisitive music) 778 00:49:56,500 --> 00:49:59,130 The season's end will cue a return 779 00:49:59,130 --> 00:50:01,683 to Antarctic waters for some of these pods. 780 00:50:04,680 --> 00:50:07,400 Many other species from around the world 781 00:50:07,400 --> 00:50:10,250 will travel these underwater current highways 782 00:50:10,250 --> 00:50:13,363 to spend a part of their year near the southern continent. 783 00:50:19,290 --> 00:50:23,773 They're nearly all seasonal visitors and world travelers. 784 00:50:26,390 --> 00:50:28,240 In every corner of the south, 785 00:50:28,240 --> 00:50:31,823 these animals find places to call home for a short while. 786 00:50:33,810 --> 00:50:37,690 They return to the same areas time and time again, 787 00:50:37,690 --> 00:50:41,430 handing down dances, greetings, 788 00:50:41,430 --> 00:50:45,783 and strategies for surviving the wildest Antarctic. 789 00:50:50,336 --> 00:50:53,253 (empowering music)