1 00:00:37,572 --> 00:00:40,632 This is a journey up the coast of South America 2 00:00:40,775 --> 00:00:43,437 following the ocean currents through stormy seas 3 00:00:43,578 --> 00:00:46,376 and some of the richest waters on the planet. 4 00:00:49,083 --> 00:00:51,210 Running over three thousand miles 5 00:00:51,352 --> 00:00:53,616 from almost the Antarctic to the tropics 6 00:00:53,755 --> 00:00:56,485 these shores are truly extraordinary. 7 00:00:57,292 --> 00:01:00,227 They support the greatest concentration of marine mammals 8 00:01:00,361 --> 00:01:02,226 and seabirds on earth. 9 00:01:20,582 --> 00:01:23,244 But what makes these waters so special? 10 00:01:23,751 --> 00:01:26,219 What feeds these teeming millions? 11 00:01:26,754 --> 00:01:28,619 From Antarctic to Equator 12 00:01:28,756 --> 00:01:31,088 one creature above all has unlocked the secret 13 00:01:31,225 --> 00:01:33,750 of life on these bountiful shores 14 00:01:34,362 --> 00:01:35,420 the penguin. 15 00:01:52,780 --> 00:01:55,647 Our journey begins off the tip of South America 16 00:01:55,783 --> 00:01:59,116 where the continent projects into the Southern Ocean. 17 00:01:59,253 --> 00:02:01,050 With little land to break their force 18 00:02:01,189 --> 00:02:04,283 furious winds rage right around the world. 19 00:02:05,159 --> 00:02:08,788 These are some of the most tempestuous waters on the planet. 20 00:02:27,615 --> 00:02:32,018 It's hard to imagine how anything could live in a place like this 21 00:02:37,892 --> 00:02:41,191 But penguins live here in their millions. 22 00:02:59,414 --> 00:03:03,180 The penguins spend months at a time out in the Southern Ocean 23 00:03:03,317 --> 00:03:06,309 but once a year they're forced to return to land. 24 00:03:14,028 --> 00:03:16,997 But getting ashore is not going to be easy. 25 00:03:25,573 --> 00:03:29,942 The dangers of riding massive waves are nothing compared to the perils 26 00:03:30,044 --> 00:03:31,944 of trying to land on slippery rocks 27 00:03:32,013 --> 00:03:33,844 armed with only strong feet 28 00:03:33,981 --> 00:03:38,350 sharp claws and grim determination to get them ashore. 29 00:04:32,473 --> 00:04:35,340 These aren't called rockhopper penguins for nothing. 30 00:04:35,476 --> 00:04:39,606 But why do they take such risks to fight their way ashore? 31 00:04:42,717 --> 00:04:44,582 They've come here to nest. 32 00:04:51,192 --> 00:04:54,787 Few islands break the vastness of the cold southern seas 33 00:04:54,996 --> 00:04:58,488 and those that do are seldom more than barren rock. 34 00:04:58,633 --> 00:05:02,296 But a handful are larger like the Falklands. 35 00:05:02,436 --> 00:05:05,803 When sea levels were lower they were connected to South America 36 00:05:05,940 --> 00:05:09,376 but now they lie three hundred miles off the coast. 37 00:05:10,578 --> 00:05:11,977 They're not just rock 38 00:05:12,113 --> 00:05:14,308 but their interior's hardly more welcoming 39 00:05:14,448 --> 00:05:18,077 a treeless expanse of windblown tussock grass. 40 00:05:18,753 --> 00:05:19,447 For the penguins 41 00:05:19,587 --> 00:05:22,147 this will be home for the next six months. 42 00:05:22,290 --> 00:05:25,919 Three hundred thousand pairs of rockhoppers breed on the Falklands 43 00:05:25,993 --> 00:05:28,928 almost two thirds of the world population. 44 00:05:29,564 --> 00:05:32,590 With good breeding sites so scarce in the Southern Ocean 45 00:05:32,733 --> 00:05:35,668 they jostle for space with all sorts of other seabirds 46 00:05:35,803 --> 00:05:38,271 like black-browed albatross. 47 00:05:59,694 --> 00:06:02,754 It's a rush to rear their young while summer lasts 48 00:06:02,930 --> 00:06:05,421 and the penguins face a tortuous trek every time 49 00:06:05,566 --> 00:06:07,591 they go back to the sea for food. 50 00:06:15,476 --> 00:06:17,341 At least the albatross can fly 51 00:06:17,478 --> 00:06:19,309 but only with help from the elements. 52 00:06:20,181 --> 00:06:24,242 The Falkland's strong winds are just what these huge birds need to take off. 53 00:06:31,959 --> 00:06:33,153 But how do these cold 54 00:06:33,294 --> 00:06:36,821 turbulent seas support such great numbers of birds? 55 00:06:47,975 --> 00:06:48,805 Surprisingly 56 00:06:48,976 --> 00:06:52,571 the cold itself is a key to the oceans' riches. 57 00:06:53,347 --> 00:06:55,679 Cold water holds more oxygen. 58 00:06:55,816 --> 00:06:57,579 That, combined with nutrients 59 00:06:57,718 --> 00:06:59,208 stirred up by rough seas 60 00:06:59,353 --> 00:07:01,321 and the long summer days of sunlight 61 00:07:01,455 --> 00:07:03,514 makes the water very fertile. 62 00:07:04,258 --> 00:07:08,957 It supports huge shoals of krill... shrimp-like crustaceans. 63 00:07:09,096 --> 00:07:12,122 They feed everything from whales to penguins. 64 00:07:35,957 --> 00:07:38,152 Porpoising like this reduces drag 65 00:07:38,292 --> 00:07:41,159 so it uses less energy than normal swimming 66 00:07:41,295 --> 00:07:44,924 and it lets the penguins see where they are going when they come in to land. 67 00:08:00,214 --> 00:08:02,205 These are gentoo penguins. 68 00:08:02,350 --> 00:08:04,477 They're twice the size of rockhoppers 69 00:08:04,618 --> 00:08:07,109 so they're not as good at climbing cliffs. 70 00:08:07,254 --> 00:08:10,223 They nest on the beach or flat ground inland. 71 00:08:10,691 --> 00:08:13,626 The cliffs above are crowded with king cormorants. 72 00:08:13,761 --> 00:08:16,195 All the birds here have their own preferences 73 00:08:16,330 --> 00:08:19,026 and good breeding sites are in short supply. 74 00:08:30,745 --> 00:08:34,374 Gentoos force their chicks to chase them for their food. 75 00:08:34,515 --> 00:08:37,348 It's a race that sorts out the weak from the strong. 76 00:08:39,120 --> 00:08:41,145 Like most penguins they lay two eggs 77 00:08:41,288 --> 00:08:44,815 but sometimes they can only catch enough food to rear one. 78 00:08:45,226 --> 00:08:46,158 When times are hard 79 00:08:46,293 --> 00:08:50,024 the winner takes all... and the weaker chick dies. 80 00:08:52,199 --> 00:08:55,259 And there's competition from another quarter. 81 00:08:55,403 --> 00:08:59,931 Piratical skuas and gulls cash in on the penguins' hard work. 82 00:09:05,012 --> 00:09:06,980 The waters offshore may be prolific 83 00:09:07,114 --> 00:09:08,741 but with so many birds breeding 84 00:09:08,916 --> 00:09:11,976 all have to fight for their share of food... 85 00:09:16,023 --> 00:09:18,651 The Southern Ocean may be a tough place to live 86 00:09:18,793 --> 00:09:21,523 but penguins are great survivors. 87 00:09:24,932 --> 00:09:26,297 Two months after hatching 88 00:09:26,434 --> 00:09:29,460 the chicks make their first acquaintance with the sea... 89 00:09:29,837 --> 00:09:33,568 its riches... and its dangers. 90 00:09:43,717 --> 00:09:46,447 Not a shark, but a killer whale. 91 00:10:01,368 --> 00:10:02,960 If the whale slips under the waves 92 00:10:03,104 --> 00:10:06,301 the penguins can't see it through the surface reflections. 93 00:10:08,576 --> 00:10:10,669 They have no idea where it is. 94 00:10:35,402 --> 00:10:39,099 Pods of killer whales come here every summer to hunt penguins 95 00:10:39,240 --> 00:10:43,040 after their main prey seals have left the islands. 96 00:10:43,978 --> 00:10:46,173 Their technique of stealth in the shallows 97 00:10:46,313 --> 00:10:49,214 is passed on from parents to young 98 00:10:49,416 --> 00:10:52,442 using dead penguins as target practice. 99 00:11:13,874 --> 00:11:15,933 As the frigid waters of the Southern Ocean 100 00:11:16,043 --> 00:11:18,273 surge around the base of the world 101 00:11:18,412 --> 00:11:22,542 only the southern tip of South America interrupts their path. 102 00:11:24,185 --> 00:11:26,710 But it isn't an impenetrable barrier. 103 00:11:26,854 --> 00:11:29,948 It's a maze of channels and islands. 104 00:11:30,024 --> 00:11:32,959 Deep fjords extend far into the interior 105 00:11:33,093 --> 00:11:37,757 letting rich, cold water reach right to the foot of the Andes. 106 00:11:51,712 --> 00:11:56,172 The forces that carved these channels begin high in the mountains. 107 00:12:02,790 --> 00:12:07,625 Huge glaciers grind their way down from the great Patagonian ice-sheet. 108 00:12:08,062 --> 00:12:10,553 When the ice-sheet was even larger than it is today 109 00:12:10,698 --> 00:12:13,929 these glaciers scoured deep trenches in the rock. 110 00:12:22,710 --> 00:12:26,942 The valleys they created filled with the rising waters of the sea. 111 00:12:28,582 --> 00:12:31,346 Some were gouged so deep that only just offshore 112 00:12:31,485 --> 00:12:35,945 the bottom is an incredible hundred and twenty metres down. 113 00:12:38,058 --> 00:12:42,358 This labyrinth of channels is one of the least explored areas on earth. 114 00:12:45,599 --> 00:12:49,035 As the cold water pushes deep into the heart of Patagonia 115 00:12:49,169 --> 00:12:52,605 it brings with it the animals of the southern ocean... 116 00:12:55,676 --> 00:12:57,041 Like fur seals. 117 00:12:58,879 --> 00:13:01,370 Mostly they live on the exposed coast 118 00:13:01,515 --> 00:13:04,609 but wandering young males are drawn into these sheltered fjords 119 00:13:04,752 --> 00:13:06,117 by the rich feeding here. 120 00:13:08,656 --> 00:13:13,355 They can dive as deep as 170 metres to hunt the sea floor 121 00:13:13,494 --> 00:13:15,155 but they feed mostly at night 122 00:13:15,296 --> 00:13:17,628 when the fish come closer to the surface. 123 00:13:20,601 --> 00:13:23,035 Large eyes help them see in the dark 124 00:13:23,170 --> 00:13:25,934 and they may also use echo location 125 00:13:35,783 --> 00:13:37,375 The fjords are often stormy 126 00:13:37,518 --> 00:13:39,850 but they're less exposed than the open ocean 127 00:13:39,987 --> 00:13:43,980 so these fur seals can take advantage of the calm waters to rest. 128 00:13:46,660 --> 00:13:50,187 On the edge of the channels are great forests of kelp. 129 00:13:50,864 --> 00:13:54,356 This giant seaweed is the fastest growing plant in the world. 130 00:13:54,601 --> 00:13:57,399 Its stems can be up to thirty metres long. 131 00:14:09,750 --> 00:14:13,186 Like any jungle the kelp has its predators. 132 00:14:14,521 --> 00:14:17,979 These aren't fur seals but sea-lions. 133 00:14:18,392 --> 00:14:20,826 They prefer to hunt in these shallower waters 134 00:14:20,961 --> 00:14:24,021 searching for animals hiding amongst the weed. 135 00:14:29,670 --> 00:14:33,003 Kelp beds are the rainforests of the sea. 136 00:14:33,273 --> 00:14:36,106 From sunlit canopy to shadowy forest floor 137 00:14:36,243 --> 00:14:39,007 they support a wealth of strange creatures. 138 00:14:39,980 --> 00:14:43,245 It's an ideal hunting ground for sea-lions. 139 00:14:48,455 --> 00:14:49,581 Like the rainforest 140 00:14:49,723 --> 00:14:52,624 this is a world that has yet to be fully explored. 141 00:15:09,209 --> 00:15:10,369 Like birds of prey 142 00:15:10,511 --> 00:15:14,447 the sea-lions fly among the branches of this submarine forest. 143 00:15:25,793 --> 00:15:28,261 There's forest on the land as well. 144 00:15:28,395 --> 00:15:32,024 These deep valleys give a degree of shelter from the relentless wind 145 00:15:32,166 --> 00:15:35,465 and with the heavy rainfall trees flourish. 146 00:15:43,710 --> 00:15:46,702 Deep in the woods, something stirs. 147 00:16:03,764 --> 00:16:08,258 The cold waters of the fjords have even put a penguin in the forest. 148 00:16:10,404 --> 00:16:13,066 These are Magellanic penguins. 149 00:16:16,610 --> 00:16:18,737 Penguins may be elegant in the water 150 00:16:18,946 --> 00:16:21,710 but they're not designed for clambering over branches. 151 00:16:21,849 --> 00:16:23,646 So what are they doing here? 152 00:16:32,326 --> 00:16:35,318 With no broad beaches or broken cliffs to breed on 153 00:16:35,462 --> 00:16:37,953 these adaptable birds actually nest here 154 00:16:38,098 --> 00:16:41,556 scraping a hollow for their eggs among the tree roots. 155 00:16:48,475 --> 00:16:51,376 Nesting in the woods gives them shelter from the elements 156 00:16:51,512 --> 00:16:54,106 and protection against predators... 157 00:16:54,248 --> 00:16:55,738 but when they have chicks to feed 158 00:16:55,883 --> 00:16:58,613 they face a hard trek back to the sea. 159 00:17:13,934 --> 00:17:17,495 Those strange calls gather them into social groups on the shore 160 00:17:17,638 --> 00:17:19,799 before they head out to sea. 161 00:17:20,307 --> 00:17:24,539 It's no surprise that they're often called jackass penguins. 162 00:17:31,718 --> 00:17:33,015 To reach their fishing ground 163 00:17:33,153 --> 00:17:35,951 the penguins have to cross the kelp beds. 164 00:17:37,824 --> 00:17:40,816 But that's where the sea-lions are hiding. 165 00:17:44,498 --> 00:17:47,296 And some sea-lions eat penguins. 166 00:17:52,806 --> 00:17:56,367 Lone males are the most dangerous. 167 00:18:02,082 --> 00:18:05,609 The penguins can't tell if the sea-lion's still there. 168 00:18:05,919 --> 00:18:09,878 They can't see through the water surface and the dense kelp forest 169 00:18:22,202 --> 00:18:26,002 They have to run the gauntlet or their chicks will starve. 170 00:18:26,139 --> 00:18:29,438 The only question is when to go into the water. 171 00:18:30,978 --> 00:18:32,570 It's time to chance it. 172 00:18:45,859 --> 00:18:47,383 There's safety in numbers 173 00:18:47,527 --> 00:18:49,995 but this straggler's missed the group. 174 00:18:50,364 --> 00:18:53,925 His chick needs feeding so he has to take a gamble. 175 00:19:16,823 --> 00:19:18,154 After killing the penguin 176 00:19:18,291 --> 00:19:21,260 the sealion skins it before eating it. 177 00:19:29,136 --> 00:19:31,229 Safely out in the depths of the fjord 178 00:19:31,371 --> 00:19:34,534 the penguins become the hunters not the hunted. 179 00:19:37,811 --> 00:19:42,510 Their prey here aren't krill but fish... sardines. 180 00:19:46,553 --> 00:19:50,319 Flocks of skuas gulls and albatross follow the action. 181 00:19:51,425 --> 00:19:53,620 The penguins hunt as a group 182 00:19:53,760 --> 00:19:55,751 herding the fish into dense shoals. 183 00:19:55,996 --> 00:19:57,122 In their panic to escape 184 00:19:57,264 --> 00:19:58,629 they're driven to the surface 185 00:19:58,765 --> 00:20:01,097 where they're easy prey for the seabirds. 186 00:20:21,288 --> 00:20:25,349 On land, penguins look ungainly even comical... 187 00:20:25,492 --> 00:20:28,154 but underwater they're in their element. 188 00:20:31,698 --> 00:20:35,429 They may be flightless but here they really fly. 189 00:20:41,575 --> 00:20:45,067 The fjords are more than just sheltered feeding places. 190 00:20:45,212 --> 00:20:48,079 They're highways for all sorts of travellers. 191 00:20:52,385 --> 00:20:56,344 One channel cuts all the way through from the Atlantic to the Pacific 192 00:20:56,490 --> 00:20:58,117 the Straits of Magellan. 193 00:21:02,662 --> 00:21:06,189 Peale's dolphins take advantage of this highway between the oceans. 194 00:21:06,333 --> 00:21:06,924 They're small 195 00:21:07,067 --> 00:21:08,625 but strong and agile 196 00:21:08,769 --> 00:21:11,465 perfectly designed for travel through kelp forests 197 00:21:11,605 --> 00:21:14,199 narrow channels and strong currents. 198 00:21:15,509 --> 00:21:18,569 They can reach speeds of over 15 miles an hour. 199 00:21:48,542 --> 00:21:50,203 At the Pacific end of the straits 200 00:21:50,343 --> 00:21:55,371 the waters of the Southern Ocean mingle with the cold Humboldt current. 201 00:21:55,682 --> 00:21:58,344 It's channelled north for two thousand miles 202 00:21:58,485 --> 00:22:03,354 by a deep ocean trench... as deep as the Andes are high. 203 00:22:04,858 --> 00:22:09,227 This current is the key to life on South America's west coast. 204 00:22:19,139 --> 00:22:22,700 The Humboldt is also a highway for sperm whales. 205 00:22:22,843 --> 00:22:25,937 Males feed in the frozen waters of the Antarctic 206 00:22:26,046 --> 00:22:29,504 but the females and young live all year round in the tropics. 207 00:22:29,649 --> 00:22:30,843 So each year 208 00:22:30,984 --> 00:22:36,388 these fifty ton giants swim five thousand miles to find a mate. 209 00:22:48,668 --> 00:22:52,434 The depth of the ocean trench along which it travels is one reason 210 00:22:52,572 --> 00:22:55,063 for the Humboldt current's fertility. 211 00:22:55,208 --> 00:22:58,177 The cold water in the abyss is rich in nutrients 212 00:22:58,311 --> 00:23:01,007 from the remains of dead plants and animals. 213 00:23:01,448 --> 00:23:02,608 It's drawn to the surface 214 00:23:02,749 --> 00:23:06,685 when the upper layers of water are displaced by strong winds. 215 00:23:07,053 --> 00:23:08,543 These enriched upwellings 216 00:23:08,688 --> 00:23:11,748 feeds the most prolific fishing grounds on earth. 217 00:23:14,127 --> 00:23:17,790 The Humboldt current brings the whole coast alive. 218 00:23:32,178 --> 00:23:34,271 As the Humboldt surges up the coast 219 00:23:34,414 --> 00:23:37,815 the rain-soaked forests of the south are left behind. 220 00:23:40,020 --> 00:23:44,957 Trees give way to the driest desert on earth... the Atacama. 221 00:23:51,865 --> 00:23:54,766 It's a strange paradox that the world's driest land 222 00:23:54,901 --> 00:23:58,302 and richest sea are found side by side. 223 00:23:58,772 --> 00:24:01,263 But even with the Humboldt current just offshore 224 00:24:01,408 --> 00:24:04,002 how could anything possibly live here? 225 00:24:15,055 --> 00:24:18,616 Incredibly this desert has penguins... 226 00:24:25,565 --> 00:24:28,796 They're Humboldt penguins... named like the current 227 00:24:28,969 --> 00:24:33,133 after the 19th Century explorer Alexander von Humboldt. 228 00:24:33,406 --> 00:24:36,341 To take advantage of the shoals of fish just offshore 229 00:24:36,476 --> 00:24:38,444 they have to nest in the desert. 230 00:24:56,529 --> 00:24:59,726 This appears to be the ultimate challenge for a penguin. 231 00:24:59,866 --> 00:25:01,094 The woolly chicks, especially 232 00:25:01,234 --> 00:25:04,169 don't look as though they could cope with a hot climate. 233 00:25:04,304 --> 00:25:07,171 And squabbling for food must make it even worse. 234 00:25:08,975 --> 00:25:12,411 Penguins do have to be tough and adaptable to live here 235 00:25:12,545 --> 00:25:15,480 but it's actually not as hot as it appears. 236 00:25:15,782 --> 00:25:18,376 The cold Humboldt current keeps the narrow strip of land 237 00:25:18,518 --> 00:25:21,385 just inshore quite cool. 238 00:25:21,688 --> 00:25:25,556 So long as the penguins keep close to the water, they can survive 239 00:25:29,229 --> 00:25:32,426 The penguins are here because of the fish. 240 00:25:32,565 --> 00:25:36,331 Just a little further up the coast are the richest fishing grounds of all 241 00:25:36,469 --> 00:25:38,334 the richest in the world. 242 00:25:39,239 --> 00:25:41,503 The Humboldt current runs close offshore 243 00:25:41,641 --> 00:25:46,544 and here the vigorous upwellings feed huge shoals of anchovies. 244 00:25:50,750 --> 00:25:55,278 This paradise of surf and seafood is called Paracas. 245 00:26:43,236 --> 00:26:45,796 Paracas is a place of superlatives. 246 00:26:45,972 --> 00:26:50,636 Just one of its sea-lion colonies can have thirty thousand animals. 247 00:26:53,046 --> 00:26:54,343 With so many packed together 248 00:26:54,481 --> 00:26:58,212 it's hard for the bulls to keep control of their harem of females. 249 00:26:58,585 --> 00:27:00,382 Disputes are inevitable. 250 00:27:27,280 --> 00:27:29,680 Paracas has more than sea-lions. 251 00:27:29,816 --> 00:27:32,478 All kinds of bird flock here to take advantage 252 00:27:32,619 --> 00:27:34,484 of the huge shoals of anchovies 253 00:27:34,621 --> 00:27:39,388 whose populations are estimated not in millions, but trillions. 254 00:27:53,506 --> 00:27:56,168 There are thought to be well over five million birds 255 00:27:56,309 --> 00:27:59,972 consuming a thousand tons of anchovies a day. 256 00:28:08,254 --> 00:28:12,691 The cormorant colonies alone contain literally millions of birds. 257 00:28:12,825 --> 00:28:15,623 There are three nests to every square metre 258 00:28:15,762 --> 00:28:18,322 and the colonies cover whole islands 259 00:28:18,464 --> 00:28:21,900 the largest concentrations of birds in the world. 260 00:28:35,782 --> 00:28:39,377 There's standing room only for Peruvian boobies too. 261 00:28:39,519 --> 00:28:43,717 Nesting on islands keeps them safe from four-footed predators 262 00:28:43,856 --> 00:28:46,984 but it's no defence against attack from the air. 263 00:29:04,277 --> 00:29:08,043 Humboldt penguins take full advantage of the rich fishing offshore 264 00:29:08,181 --> 00:29:12,584 but for them, living in Paracas has its own set of challenges. 265 00:29:15,922 --> 00:29:20,689 Knowing how to ski on sand comes in handy if you can't fly. 266 00:29:25,498 --> 00:29:26,897 But at the foot of the slope 267 00:29:27,000 --> 00:29:29,798 they have a much bigger problem to overcome. 268 00:29:31,938 --> 00:29:36,398 Their way to the sea is blocked... by potential penguin eaters. 269 00:29:36,609 --> 00:29:40,101 There are so many sea-lions that there's no way round. 270 00:29:40,246 --> 00:29:42,476 They have to make a dash for it. 271 00:30:01,801 --> 00:30:02,392 In fact 272 00:30:02,535 --> 00:30:05,060 the sea-lions here are so well fed with fish 273 00:30:05,204 --> 00:30:09,140 that the penguins are in more danger of being squashed than eaten. 274 00:30:13,946 --> 00:30:16,005 Thanks to the cold Humboldt current 275 00:30:16,149 --> 00:30:20,347 Paracas is one of the wildlife spectacles of the world. 276 00:30:22,221 --> 00:30:25,247 But what happens if the cold water disappears? 277 00:30:25,958 --> 00:30:27,152 In El Nino years 278 00:30:27,293 --> 00:30:32,128 a change in the prevailing wind brings in warm water from the tropics. 279 00:30:32,432 --> 00:30:34,900 The fertile upwellings are suppressed. 280 00:30:35,034 --> 00:30:38,595 The fish literally vanish. 281 00:30:48,648 --> 00:30:53,347 El Nino spells disaster for almost everything that lives here. 282 00:30:55,621 --> 00:30:57,020 With no fish to feed them 283 00:30:57,156 --> 00:31:00,922 the animals must either leave... or starve. 284 00:31:26,853 --> 00:31:28,115 In El Nino years 285 00:31:28,254 --> 00:31:31,348 only scavengers like the condor grow fat. 286 00:31:35,895 --> 00:31:38,227 The fish move far out into the ocean 287 00:31:38,364 --> 00:31:42,767 but the birds and animals are tied to their breeding colonies on land. 288 00:31:43,002 --> 00:31:47,598 All the young die... and many of their parents starve too. 289 00:31:55,882 --> 00:32:00,785 El Nino's effect on the Atacama coast can be catastrophic. 290 00:32:13,566 --> 00:32:15,534 The only winners are the condors 291 00:32:15,668 --> 00:32:19,536 which come down from the Andes to feast on the fallen. 292 00:32:19,772 --> 00:32:22,138 Yet even they find it hard to survive 293 00:32:22,275 --> 00:32:26,211 once the first glut of food from El Nino's victims has been exhausted. 294 00:32:37,690 --> 00:32:40,284 El Nino is part of a natural cycle. 295 00:32:40,426 --> 00:32:43,054 In time, the cold ocean current is restored 296 00:32:43,296 --> 00:32:48,131 the fish return, and slowly the seabirds and sea-lions increase. 297 00:32:49,635 --> 00:32:52,001 But as the world gets hotter because of global warming 298 00:32:52,138 --> 00:32:54,129 El Nino comes more often. 299 00:32:54,273 --> 00:32:58,209 There's less time for wildlife to recover before the next crash. 300 00:32:59,612 --> 00:33:02,308 The Humboldt penguin is already rare. 301 00:33:02,448 --> 00:33:05,076 Will it survive the next El Nino? 302 00:33:13,626 --> 00:33:17,187 The Humboldt current is the key to life in this barren land 303 00:33:17,330 --> 00:33:21,130 and so far it has always returned after El Nino. 304 00:33:33,079 --> 00:33:34,774 For over two thousand miles 305 00:33:34,981 --> 00:33:37,575 the current hugs the shores of South America. 306 00:33:39,485 --> 00:33:41,646 Now, deflected by the coast of Peru 307 00:33:41,787 --> 00:33:45,416 it turns west... out into the blue. 308 00:33:59,639 --> 00:34:03,803 The bull sperm whales are still following this highway in the sea. 309 00:34:06,178 --> 00:34:10,581 They've swum more than four thousand miles from the frigid waters of the Antarctic 310 00:34:10,716 --> 00:34:15,744 and they still have several hundred miles to go to their rendezvous on the equator. 311 00:34:28,734 --> 00:34:30,258 For the last leg of their journey 312 00:34:30,403 --> 00:34:34,396 they have new companions... bottlenosed dolphins. 313 00:34:48,854 --> 00:34:52,654 Far out into the Pacific the ocean floor is alive. 314 00:35:03,002 --> 00:35:05,493 The bubbles are signs of volcanic activity 315 00:35:05,638 --> 00:35:07,037 that's built mountains four 316 00:35:07,173 --> 00:35:09,164 and a half thousand metres high 317 00:35:09,308 --> 00:35:13,005 so high that their summits now rise above the waves. 318 00:35:22,054 --> 00:35:25,455 Lying six hundred miles west of the coast of South America 319 00:35:25,591 --> 00:35:29,027 these barren cones are the Galapagos islands. 320 00:35:37,837 --> 00:35:41,034 A visit to the Galapagos helped the young Charles Darwin 321 00:35:41,173 --> 00:35:43,937 develop his theory of evolution. 322 00:35:46,012 --> 00:35:48,310 He would have seen all sorts of strange animals 323 00:35:48,447 --> 00:35:53,009 like giant tortoises and the islands' thirteen kinds of finch. 324 00:35:53,719 --> 00:35:58,383 One does the job of a woodpecker... using a cactus spine as a tool. 325 00:36:02,294 --> 00:36:06,890 Another finch has become a bloodsucker an avian vampire bat. 326 00:36:08,634 --> 00:36:11,068 All the finches have their own unique way of life 327 00:36:11,203 --> 00:36:15,003 yet all are descended from a single seed-eating ancestor. 328 00:36:18,744 --> 00:36:21,736 Everywhere you look there's something extraordinary. 329 00:36:23,449 --> 00:36:25,815 A lizard that lives in the sea 330 00:36:27,720 --> 00:36:29,915 A cormorant that can't fly. 331 00:36:32,958 --> 00:36:34,789 Because the islands are so isolated 332 00:36:34,960 --> 00:36:38,726 the few colonists that reached them had the place to themselves. 333 00:36:39,532 --> 00:36:40,726 With no competition 334 00:36:40,866 --> 00:36:43,960 they could develop in all sorts of unlikely ways. 335 00:36:46,472 --> 00:36:48,167 The cormorant may be flightless 336 00:36:48,307 --> 00:36:49,831 but it's an expert swimmer 337 00:36:49,975 --> 00:36:53,934 superb at winkling out prey from submerged lava fields. 338 00:36:59,485 --> 00:37:02,716 The Galapagos lie right at the end of the Humboldt current. 339 00:37:02,922 --> 00:37:05,447 It reaches the islands for only part of the year 340 00:37:05,591 --> 00:37:08,651 and its arrival is erratic and unpredictable. 341 00:37:09,161 --> 00:37:13,757 Birds are constantly testing to see if the rich, cold water has arrived. 342 00:37:13,933 --> 00:37:14,729 When it does 343 00:37:14,934 --> 00:37:17,960 the flush of food triggers an orgy of breeding. 344 00:37:20,039 --> 00:37:23,270 Blue-footed boobies are foot fetishists. 345 00:37:23,409 --> 00:37:24,467 The bluer your feet 346 00:37:24,610 --> 00:37:27,204 the more healthy and fit you're likely to be 347 00:37:27,346 --> 00:37:29,906 a sure turn-on for a potential mate. 348 00:37:39,358 --> 00:37:41,326 These are waved albatross. 349 00:37:41,460 --> 00:37:46,227 Almost the entire world population breeds on one island in the Galapagos 350 00:37:46,365 --> 00:37:50,131 but only when the cold currents make conditions just right. 351 00:37:59,645 --> 00:38:03,706 Flightless cormorants also celebrate the arrival of the cold water. 352 00:38:03,916 --> 00:38:04,905 Like all the birds here 353 00:38:05,050 --> 00:38:08,110 the secret of their success is irregular breeding 354 00:38:08,254 --> 00:38:11,451 nesting only when cold water brings them food. 355 00:38:20,533 --> 00:38:22,501 With limited opportunities to breed 356 00:38:22,635 --> 00:38:26,071 it's even more important to pick the right partner. 357 00:38:26,205 --> 00:38:30,505 Some birds go to extraordinary lengths to impress a potential mate. 358 00:38:35,114 --> 00:38:36,479 Like the boobies blue feet 359 00:38:36,615 --> 00:38:39,345 the male frigate bird's red pouch is a good 360 00:38:39,485 --> 00:38:43,114 if slightly overblown way of showing how fit he is. 361 00:38:45,191 --> 00:38:49,958 The female booby can't spend forever choosing between subtle shades of blue. 362 00:38:50,095 --> 00:38:52,154 The Humboldt current is here. 363 00:38:52,298 --> 00:38:54,766 She must seize the day and pick a mate. 364 00:39:10,482 --> 00:39:13,883 Some boobies have well grown chicks from an earlier time of plenty 365 00:39:13,953 --> 00:39:16,319 when the cold water was last here. 366 00:39:18,224 --> 00:39:21,318 They take full advantage of the new flush of food. 367 00:39:21,460 --> 00:39:23,758 But they're not the only ones looking for a meal. 368 00:39:26,699 --> 00:39:30,294 The Galapagos have their own pirates... frigate birds. 369 00:39:34,807 --> 00:39:36,297 In this land of opportunists 370 00:39:36,442 --> 00:39:39,411 they'll stop at nothing to steal someone else's food. 371 00:39:59,565 --> 00:40:02,659 Down on the shoreline live the most extraordinary 372 00:40:02,801 --> 00:40:05,395 of the islands' many strange inhabitants. 373 00:40:08,140 --> 00:40:12,873 Marine iguanas... the only salt water lizards in the world. 374 00:40:23,255 --> 00:40:27,385 They eat algae... seaweed... growing on rocks between the tides 375 00:40:27,526 --> 00:40:29,323 so they have to wait for the water to go down 376 00:40:29,461 --> 00:40:30,758 before they can feed. 377 00:40:33,866 --> 00:40:37,302 They live only on shores exposed to cold currents 378 00:40:37,436 --> 00:40:41,202 but the arrival of the cold water is a double-edged sword. 379 00:40:41,874 --> 00:40:45,037 Its nutrients stimulate the growth of the algae they eat 380 00:40:45,177 --> 00:40:47,475 but because the lizards are cold-blooded 381 00:40:47,613 --> 00:40:51,709 the cold water slows them down and could even kill them. 382 00:40:53,652 --> 00:40:56,280 The best algae grow close to the low tide mark 383 00:40:56,422 --> 00:40:59,653 so it's a race to eat all they can before the rocks are covered again 384 00:40:59,792 --> 00:41:02,420 and their bodies are chilled to danger point. 385 00:41:09,234 --> 00:41:11,964 Strong claws and a good grip are essential 386 00:41:12,104 --> 00:41:13,662 if you're not to be swept away. 387 00:41:51,010 --> 00:41:54,343 For most iguanas life is ruled by the tides. 388 00:41:54,480 --> 00:41:57,074 But the big males have another option. 389 00:42:04,957 --> 00:42:06,254 Below the low tide mark 390 00:42:06,392 --> 00:42:08,417 the growths of algae are more luxuriant 391 00:42:08,560 --> 00:42:11,028 because the rocks are always covered. 392 00:42:11,597 --> 00:42:15,294 The males use the heat of the tropical sun to exploit them. 393 00:42:17,202 --> 00:42:20,763 They expose the greatest possible surface to its warming rays. 394 00:42:20,973 --> 00:42:22,497 Because their bodies are larger 395 00:42:22,641 --> 00:42:26,543 they can store more heat and don't chill down so quickly. 396 00:42:31,550 --> 00:42:34,451 When they've warmed to an optimum thirty five degrees 397 00:42:34,586 --> 00:42:35,848 they take to the water. 398 00:42:45,631 --> 00:42:48,566 Down here they can take advantage of a food supply 399 00:42:48,700 --> 00:42:50,964 that's out of reach for the smaller iguanas. 400 00:43:05,017 --> 00:43:07,781 They can hold their breath for twenty minutes or more. 401 00:43:07,953 --> 00:43:09,443 But they have to feed fast. 402 00:43:09,588 --> 00:43:10,919 Every minute they spend here 403 00:43:11,056 --> 00:43:13,047 the heat is draining from their body. 404 00:43:14,493 --> 00:43:16,085 If their temperature falls too low 405 00:43:16,228 --> 00:43:19,322 they will be unable to move... and they'll die. 406 00:43:24,736 --> 00:43:25,760 It's time to go. 407 00:43:41,854 --> 00:43:43,549 The cold waters of the Humboldt 408 00:43:43,689 --> 00:43:47,352 bring southern species all the way to the equator. 409 00:43:48,093 --> 00:43:51,688 But when cold currents give way to the warm Equatorial Current 410 00:43:51,830 --> 00:43:54,321 sea temperatures almost double. 411 00:43:54,633 --> 00:43:57,158 A whole new set of fish appears. 412 00:43:58,036 --> 00:43:59,628 This is an ocean crossroads 413 00:43:59,771 --> 00:44:02,706 with an amazing diversity of marine life. 414 00:44:14,853 --> 00:44:18,311 Hammerhead sharks are drawn here in their hundreds. 415 00:44:18,590 --> 00:44:23,050 It's thought they follow electromagnetic 'maps' on the sea floor. 416 00:44:36,508 --> 00:44:38,976 No one knows exactly what attracts them. 417 00:44:39,211 --> 00:44:41,076 There's certainly an abundance of food 418 00:44:41,213 --> 00:44:45,013 but their gathering in huge shoals suggests these mysterious fish 419 00:44:45,150 --> 00:44:49,052 may also come here to socialise and breed. 420 00:44:56,995 --> 00:45:00,897 Hammerheads are not the only ones that come to breed here. 421 00:45:02,234 --> 00:45:04,998 For the bull sperm whales this is journey's end 422 00:45:05,137 --> 00:45:08,231 the culmination of a five thousand mile odyssey 423 00:45:08,373 --> 00:45:12,241 that's brought them all the way from the Antarctic to the equator. 424 00:45:12,477 --> 00:45:16,538 At last, they join the females they've come so far to find. 425 00:45:17,749 --> 00:45:21,480 Head butting and tooth rasping sort out who's dominant. 426 00:45:21,620 --> 00:45:24,646 The winning bulls will mate with several females 427 00:45:24,790 --> 00:45:27,520 For others, the journey will have been in vain 428 00:45:27,659 --> 00:45:28,921 and in just a few weeks 429 00:45:29,061 --> 00:45:32,656 they'll take the long swim back to the Southern Ocean. 430 00:45:49,615 --> 00:45:52,482 This is the end of the road for the sperm whales 431 00:45:52,618 --> 00:45:55,086 and for the Humboldt current too. 432 00:45:55,988 --> 00:46:00,049 But the Humboldt still has one final surprise to spring. 433 00:46:09,067 --> 00:46:14,300 This cold flow has even put a penguin on the equator... 434 00:46:14,539 --> 00:46:16,404 the Galapagos penguin. 435 00:46:17,943 --> 00:46:21,310 They can thrive here in the tropics only because the current brings the rich 436 00:46:21,446 --> 00:46:23,914 cold water on which they depend. 437 00:46:32,357 --> 00:46:35,485 Over the course of our three and a half thousand mile journey 438 00:46:35,627 --> 00:46:39,495 no creatures have proved so adaptable as penguins. 439 00:46:40,132 --> 00:46:44,159 On land, they can deal with everything from forest to desert. 440 00:46:44,569 --> 00:46:48,471 But it's underwater that their true genius is revealed. 441 00:46:48,607 --> 00:46:51,542 These are superb fish catchers. 442 00:47:46,164 --> 00:47:50,931 Penguins have colonised almost the entire west coast of South America... 443 00:47:51,069 --> 00:47:55,062 but they could never have done so without the Humboldt current. 444 00:47:55,207 --> 00:47:58,005 All the way from the Southern Ocean to the equator 445 00:47:58,143 --> 00:48:02,341 that chill river in the sea feeds everything that lives here. 446 00:48:02,481 --> 00:48:07,180 It's the key to life on these penguin shores.