1 00:00:25,328 --> 00:00:29,102 The southern tip of the African continent. 2 00:00:30,043 --> 00:00:34,063 Sailors once called this "The Cape of Storms" 3 00:00:37,562 --> 00:00:41,430 These waters seem forbidding and without life. 4 00:00:43,064 --> 00:00:45,076 But just below the surface, 5 00:00:45,134 --> 00:00:48,436 one of the world's greatest wildlife spectacles 6 00:00:48,609 --> 00:00:50,503 is about to emerge. 7 00:00:51,730 --> 00:00:53,467 Rising up from the depths, 8 00:00:53,576 --> 00:00:56,289 appears to be one giant creature. 9 00:01:01,837 --> 00:01:05,320 But appearances can be deceptive. 10 00:01:06,547 --> 00:01:08,371 This is one single animal, 11 00:01:08,564 --> 00:01:12,723 but millions. It's a massive shoal of sardines 12 00:01:13,304 --> 00:01:17,345 100,000,000 little fish are about to begin 1000 mile journey 13 00:01:17,440 --> 00:01:19,256 up the African coast. 14 00:01:25,429 --> 00:01:30,194 And on course to intercept them are armies of deadly predators. 15 00:01:31,965 --> 00:01:34,835 Tens of thousands of them. 16 00:01:49,001 --> 00:01:51,360 If they will find the sardines 17 00:01:51,611 --> 00:01:55,329 one of nature's greatest confrontations will take place. 18 00:01:56,869 --> 00:01:59,739 This is Massive Nature. 19 00:02:01,115 --> 00:02:02,412 But why here ? 20 00:02:02,757 --> 00:02:04,314 And why now ? 21 00:02:28,188 --> 00:02:29,988 In an attack of this scale, 22 00:02:30,074 --> 00:02:33,415 the life of every single little fish will be on the line. 23 00:02:44,025 --> 00:02:48,640 So, at the moment of impact, is it all over for these sardines ? 24 00:02:52,590 --> 00:02:56,151 Or did some still have a change to save themselves ? 25 00:02:58,329 --> 00:03:02,071 And are these sardines the only ones in danger ? 26 00:03:06,977 --> 00:03:11,639 Because even hungry predators have predators of their own. 27 00:03:15,001 --> 00:03:18,256 Dolphins and sharks are deadly enemies. 28 00:03:18,346 --> 00:03:20,139 Will they turn on each other ? 29 00:03:20,980 --> 00:03:24,337 It's a moment when life hangs in the balance for both predator 30 00:03:24,418 --> 00:03:26,580 and prey. 31 00:03:28,741 --> 00:03:32,460 The future of all these animals would depend on a chain of events 32 00:03:32,507 --> 00:03:34,811 that begun 6 months ago, 33 00:03:36,410 --> 00:03:39,468 more than 1000 miles down the coast. 34 00:03:51,762 --> 00:03:54,325 Our story starts in deep water, 35 00:03:54,419 --> 00:03:57,485 off the southern tip of Africa, on the Agulhas bank 36 00:03:57,540 --> 00:03:59,985 a safe place for sardines. 37 00:04:00,078 --> 00:04:01,847 It's their nursery. 38 00:04:02,775 --> 00:04:05,857 Here hundreds of millions of tiny fish are growing, 39 00:04:05,895 --> 00:04:08,490 breeding and multiplying. 40 00:04:11,651 --> 00:04:14,105 They're safe here, for now. 41 00:04:14,211 --> 00:04:16,735 But they can't stay here forever. 42 00:04:17,734 --> 00:04:22,161 Before long , something will set them on a journey up the coast of Africa. 43 00:04:27,055 --> 00:04:30,789 And that something is food. 44 00:04:30,965 --> 00:04:34,722 In winter a cold current sweeps 1000 miles up the coast 45 00:04:34,805 --> 00:04:37,552 carrying with it the sardines plankton food. 46 00:04:38,060 --> 00:04:43,062 When the time comes, the sardines will have no choice, but to follow. 47 00:04:49,636 --> 00:04:54,145 Their dangerous journey will take them past Bird Island 48 00:04:54,366 --> 00:04:58,487 It's the world's largest colony of fish-eating gannets. 49 00:05:02,301 --> 00:05:06,457 Here, 100000 birds are gathering to breed. 50 00:05:15,501 --> 00:05:17,556 Timing is critical. 51 00:05:17,861 --> 00:05:23,028 Although they'll have almost 6 months to raise their chicks before the sardine shoal passes by, 52 00:05:23,265 --> 00:05:25,637 not all will be ready. 53 00:05:29,853 --> 00:05:32,648 And while the gannets await the sardine's arrival 54 00:05:32,930 --> 00:05:38,272 on a nearby island, 7000 cape-fur seals are gathering to breed. 55 00:05:47,670 --> 00:05:50,488 With such massive numbers in this colony 56 00:05:50,699 --> 00:05:54,292 the seals can't simply wait for the sardines to arrive 57 00:05:54,362 --> 00:05:56,981 they'll need to start hunting closer to home. 58 00:05:59,874 --> 00:06:03,866 And that could put the gannet chicks in real danger. 59 00:06:20,025 --> 00:06:25,826 The first great storms of winter trigger a big change in the ocean currents. 60 00:06:30,822 --> 00:06:35,519 The life-sustaining plankton is swept out of the sardine's nursery. 61 00:06:41,474 --> 00:06:47,580 And with billions of new mouths to feed, the massive shoal sets off on its epic journey. 62 00:06:50,935 --> 00:06:54,716 Sheer numbers force the sardine shoal to follow their food, 63 00:06:54,916 --> 00:06:58,755 even if it means leaving the safety of these deep waters. 64 00:07:01,260 --> 00:07:04,101 As the shoal begins its incredible journey 65 00:07:05,205 --> 00:07:10,336 hundreds of miles up the coast, yet another animal is preparing to join the hunt. 66 00:07:12,890 --> 00:07:16,859 Common dolphins thrive in the seas along the coast of Africa 67 00:07:24,407 --> 00:07:26,744 They're social, playful animals, 68 00:07:27,108 --> 00:07:30,477 but also intelligent and cunning hunters. 69 00:07:35,348 --> 00:07:40,796 These dolphins will, in fact, be the brains behind this whole sardine hunt. 70 00:07:43,248 --> 00:07:48,097 Because if they don't find the fish, then none of the other predators will, either. 71 00:07:49,765 --> 00:07:53,393 Somehow, they sense the sardines are on the move 72 00:07:53,592 --> 00:07:57,279 and they mobilize their own massive force. 73 00:07:59,487 --> 00:08:02,375 They bound together into a huge armada 74 00:08:02,608 --> 00:08:06,600 5000 strong, a dolphin super pod, 75 00:08:06,964 --> 00:08:11,708 assembled with the soul purpose of hunting down sardines. 76 00:08:14,450 --> 00:08:18,571 But in these numbers, they can also become a target. 77 00:08:20,588 --> 00:08:24,474 For in these same coastal waters are sharks. 78 00:08:27,290 --> 00:08:33,501 They're normally solitary hunters, except when there's a dolphin super pod on the move. 79 00:08:35,671 --> 00:08:42,282 Now they too gather in their thousands, and begin their search for the dolphins. 80 00:08:43,583 --> 00:08:49,712 But will these sharks find the dolphins, before the dolphins find the sardines ? 81 00:08:55,605 --> 00:08:59,445 Halfway through their journey, and still safe in deep water, 82 00:08:59,539 --> 00:09:02,122 the shoal moves on relentlessly. 83 00:09:02,425 --> 00:09:06,112 Each little fish is blissfully unaware of the gathering of predators 84 00:09:06,182 --> 00:09:08,742 Amassing in their honor. 85 00:09:12,408 --> 00:09:16,259 On Bird Island, the gannet chicks have hatched. 86 00:09:27,204 --> 00:09:29,647 These young birds must fatten up fast, 87 00:09:29,752 --> 00:09:33,521 and learn to fly soon, if they are going to join the sardine hunt. 88 00:09:43,227 --> 00:09:45,611 They'll need these fat reserves to tide them over 89 00:09:45,658 --> 00:09:48,781 until they can learn to fly with the rest of the colony, 90 00:09:53,164 --> 00:09:56,663 and that will make them a target. 91 00:10:00,503 --> 00:10:03,016 Nearby, at the seal colony, 92 00:10:03,389 --> 00:10:07,569 a new generation of predators is about to take to the water. 93 00:10:09,976 --> 00:10:14,515 And all these pups will soon be learning their own survival skills. 94 00:10:16,073 --> 00:10:20,605 As the numbers swell, the pressure mounts on the seals, too. 95 00:10:26,830 --> 00:10:33,100 And, like the gannets, they will be forced to leave these islands, in search of food. 96 00:10:33,966 --> 00:10:38,229 When that time comes, these young pups will have to fend for themselves, 97 00:10:38,311 --> 00:10:41,317 in ever more dangerous waters. 98 00:10:47,854 --> 00:10:51,071 The odds seem to be stacking up against the sardines 99 00:10:51,177 --> 00:10:56,106 but for now they're safe, so long as they remain in deep water. 100 00:10:56,400 --> 00:11:00,266 And even if they were to be found here, being part of the massive shoal 101 00:11:00,267 --> 00:11:03,097 means the odds of survival are good. 102 00:11:03,167 --> 00:11:05,997 But shoaling comes at a cost. 103 00:11:10,197 --> 00:11:15,363 Hiding in the middle, a fish may be safe, but there's precious little food here. 104 00:11:16,976 --> 00:11:22,295 So each fish must take its turn at the edge of the shoal, where it can feed, 105 00:11:25,313 --> 00:11:28,307 but where it also risks becoming food. 106 00:11:29,220 --> 00:11:34,069 Being part of the massive shoal, also makes them easier to find. 107 00:11:35,901 --> 00:11:40,278 And there's one predator with a plan to do just that. 108 00:11:43,528 --> 00:11:50,057 A few hundred miles off the coast, the dolphin super pod is now on the move. 109 00:11:51,945 --> 00:11:56,383 With so many mouths to feed, their search is becoming desperate. 110 00:11:57,018 --> 00:12:00,329 They're now using a combination of intelligence and sonar 111 00:12:00,385 --> 00:12:03,426 to try and locate the sardine shoal. 112 00:12:08,848 --> 00:12:12,148 Highly organized, they set up a sweeping front 113 00:12:12,195 --> 00:12:17,807 a line of scouts, several miles wide, to scan the sea for signs of the sardines. 114 00:12:22,633 --> 00:12:25,568 But as a dolphin's sonar beams out 115 00:12:25,627 --> 00:12:29,314 they alert their presence to their predators. 116 00:12:33,812 --> 00:12:37,851 It's exactly the signal these sharks are waiting for. 117 00:12:51,419 --> 00:12:55,670 Around Bird Island, the food is running out. 118 00:13:12,143 --> 00:13:18,143 The gannets must join the sardine hunt, and the fledglings will have to follow. 119 00:13:23,125 --> 00:13:26,553 They've been preparing for this moment for weeks 120 00:13:26,647 --> 00:13:29,853 now it's time to put their wings to the test. 121 00:13:37,002 --> 00:13:43,730 With hungry seals nearby, now it's literally fly, or die. 122 00:14:18,664 --> 00:14:23,090 One the gannets are gone, the seals must follow. 123 00:14:33,768 --> 00:14:36,845 But they're not all ready to live. 124 00:14:38,359 --> 00:14:43,349 Pups born late in the season, are to small and weak to join the crowd. 125 00:14:43,678 --> 00:14:47,647 And these waters are dangerous, for those who go alone. 126 00:14:52,565 --> 00:14:58,201 And, until the sardines are found, these are very dangerous waters. 127 00:15:45,242 --> 00:15:49,962 The gannets now spot the dolphins, and start to track their movements, 128 00:15:50,514 --> 00:15:53,907 while the seals follow on from below. 129 00:15:59,749 --> 00:16:04,026 The fate of all these animals now rests with the dolphin's success 130 00:16:04,085 --> 00:16:07,161 at hunting down the shoal of sardines. 131 00:16:20,262 --> 00:16:23,045 So, where on earth are they ? 132 00:16:31,305 --> 00:16:37,634 With just 24 hours to go, nature now starts working for the predators. 133 00:16:38,174 --> 00:16:42,545 The cold food-rich current is letting the sardines out of deep water, 134 00:16:42,662 --> 00:16:45,058 and into the shallows, 135 00:16:46,162 --> 00:16:48,087 at waterfall bluff. 136 00:16:48,236 --> 00:16:52,428 It's the perfect spot for an ambush. 137 00:17:00,686 --> 00:17:05,711 Until now, the sardines have remained out of range of most predators 138 00:17:05,840 --> 00:17:10,408 but if they're caught in these shallow waters, they'll be at their most vulnerable. 139 00:17:28,571 --> 00:17:33,009 It's dawn, the most dangerous time for the sardines. 140 00:17:34,101 --> 00:17:36,590 Overnight, they've been feeding at the surface, 141 00:17:36,666 --> 00:17:39,907 protected by the cloak of darkness. 142 00:17:46,554 --> 00:17:50,616 But with the sunrise, they need to dive to safety. 143 00:17:59,702 --> 00:18:04,528 And it's now, that finally, the dolphins track them down. 144 00:18:10,823 --> 00:18:17,164 These waters may be shallow for sardines, but the dolphins are at their limit of their diving range. 145 00:18:17,866 --> 00:18:21,659 They must be quick, before the shoal is lost to the deep. 146 00:18:22,821 --> 00:18:25,322 So, how will they catch them ? 147 00:18:42,545 --> 00:18:47,641 It's a race against time. The shoal is sinking fast. 148 00:18:49,878 --> 00:18:53,506 But these dolphins have a remarkable plan. 149 00:18:54,434 --> 00:18:59,001 An individual can only hold its breath for a few minutes at a time. 150 00:19:01,442 --> 00:19:04,224 So, the dolphins work as a team, 151 00:19:04,295 --> 00:19:08,146 relaying to the surface, to breathe. 152 00:19:10,375 --> 00:19:13,333 By constantly blowing bubbles into the shoal, 153 00:19:13,604 --> 00:19:16,797 the dolphins confuse the sardines. 154 00:19:17,467 --> 00:19:21,408 Eventually, they manage to isolate and disorient a group. 155 00:19:24,810 --> 00:19:26,923 And bring it to the surface. 156 00:19:28,404 --> 00:19:30,835 The result is a bait ball, 157 00:19:31,046 --> 00:19:34,662 a swirling, churning mass of terrified fish. 158 00:19:35,062 --> 00:19:37,163 They're still 20000 strong, 159 00:19:37,302 --> 00:19:40,531 but now, they're all in serious trouble. 160 00:19:53,348 --> 00:19:55,215 With just seconds to go, 161 00:19:55,379 --> 00:19:59,134 the dolphins have got the sardines exactly where they want them. 162 00:20:02,900 --> 00:20:08,337 And just before the attack, they set their sonar to stun mode. 163 00:20:10,424 --> 00:20:14,005 Now, every single little fish is at risk. 164 00:20:14,228 --> 00:20:17,152 Each , instinctively searches for the safety of the crowd, 165 00:20:17,223 --> 00:20:20,381 but in a bait ball, nowhere is safe. 166 00:20:42,135 --> 00:20:48,112 Still, the dolphins must keep the bait ball near the surface, in close diving range. 167 00:20:50,296 --> 00:20:52,973 They can't do that and attack in the same time. 168 00:20:53,140 --> 00:20:54,831 They need help. 169 00:20:55,888 --> 00:21:01,653 And right on queue, guided by the dolphin's sonar, the sharks have arrived. 170 00:21:05,561 --> 00:21:08,837 With literally thousands drawn to the feeding frenzy, 171 00:21:09,024 --> 00:21:12,911 the dolphins are now in great danger 172 00:21:14,886 --> 00:21:18,879 The sharks approach from below, and start their attack. 173 00:21:21,227 --> 00:21:23,904 But at the final moment, their focus changes. 174 00:21:24,008 --> 00:21:27,788 The bait ball becomes their target, too. 175 00:21:28,000 --> 00:21:33,237 Instead of attacking the dolphins, these sharks become their allies. 176 00:21:35,888 --> 00:21:38,436 Sharks don't need to surface for air, 177 00:21:38,565 --> 00:21:41,442 and they now lead the attack from below the bait ball. 178 00:21:42,426 --> 00:21:46,230 The sardines only escape route is closed. 179 00:22:15,867 --> 00:22:21,010 So, is it all over for the bait ball, or these sardines still have a chance ? 180 00:22:28,065 --> 00:22:31,423 If they can spread out thinly, just below the surface 181 00:22:31,481 --> 00:22:34,981 they'll present no clear target for the predators. 182 00:22:39,180 --> 00:22:43,019 But once more, the dolphins are ahead of the game. 183 00:22:46,874 --> 00:22:51,793 They split into platoons, some circling around the sardines, 184 00:22:51,946 --> 00:22:54,999 leaving others free to continue the attack. 185 00:22:58,510 --> 00:23:01,163 It's a deadly alliance of predators, 186 00:23:01,234 --> 00:23:04,862 a pincer movement, dolphins attacking from the side, 187 00:23:04,897 --> 00:23:07,292 as sharks lunge from below. 188 00:23:09,894 --> 00:23:12,877 Things are looking bad for the sardines, 189 00:23:12,959 --> 00:23:15,390 and there are about to get much worse. 190 00:23:18,381 --> 00:23:23,512 from the skies above, the gannets roar down, like fish-seeking missiles. 191 00:23:29,436 --> 00:23:34,884 Hitting the water at 60 mph, and plunging to a depth of 20 feet 192 00:23:37,570 --> 00:23:40,635 The attack brings more birds to the bait ball. 193 00:23:43,817 --> 00:23:48,361 Soon, there's thousands of them, raining death from above. 194 00:24:30,312 --> 00:24:34,222 But there's still one predator missing from the scene. 195 00:24:34,891 --> 00:24:36,923 The fur seals. 196 00:24:38,077 --> 00:24:42,257 And now, the last group of hunters arrive, for their share of the killing. 197 00:24:45,146 --> 00:24:48,316 But, will the gannets, or the sardines be their target ? 198 00:24:54,917 --> 00:24:56,925 Like the sharks and the dolphins, 199 00:24:57,052 --> 00:25:01,021 the seals and gannets ignore each other, when they found a bait ball. 200 00:25:07,234 --> 00:25:11,014 This bait ball faces extinction. 201 00:25:14,977 --> 00:25:19,521 With so many predators, every single fish will be eaten. 202 00:25:31,185 --> 00:25:37,632 Day after day, bait balls like this are created and destroyed by these predators. 203 00:25:51,060 --> 00:25:54,676 But the sardine story doesn't end here. 204 00:25:57,541 --> 00:26:03,222 Though huge, the bait ball is just a small part of this massive shoal. 205 00:26:04,953 --> 00:26:09,497 Becoming separated, was what made those fish vulnerable. 206 00:26:13,064 --> 00:26:17,995 But even in a shoal of this size, they're still not entirely safe. 207 00:26:20,846 --> 00:26:24,404 The army of allied predators may have disbanded, 208 00:26:24,474 --> 00:26:27,363 but the danger still remains. 209 00:26:31,039 --> 00:26:34,632 Now the food-rich currents are pinning them in the shallows, 210 00:26:34,785 --> 00:26:37,931 where their predators can easily attack. 211 00:26:39,667 --> 00:26:43,577 Sharks have no need for the dolphins here. 212 00:26:46,956 --> 00:26:51,876 And in these shallows, the fish now face another enemy. 213 00:26:55,305 --> 00:27:00,318 A 20 ton Bryde's whale can swallow 10000 sardines 214 00:27:00,389 --> 00:27:02,573 in a single gulp. 215 00:27:24,997 --> 00:27:27,815 Those fish that have survived all these attacks 216 00:27:27,909 --> 00:27:31,572 must face one final challenge. 217 00:27:33,166 --> 00:27:37,722 Trapped in these warm shallow waters, the fish begin to suffocate 218 00:27:37,968 --> 00:27:41,327 victims of their own massive numbers. 219 00:27:42,675 --> 00:27:46,338 But just as it looks like the end for every single sardine, 220 00:27:46,597 --> 00:27:48,933 nature takes the reigns. 221 00:27:52,925 --> 00:27:56,835 Once again, the currents change, steering them out of the shallows 222 00:27:56,917 --> 00:28:00,874 and releasing them back into the safety of the deep. 223 00:28:05,239 --> 00:28:08,280 The Africa sardine is a gambler. 224 00:28:08,890 --> 00:28:12,460 It plays the number's game and wins. 225 00:28:14,133 --> 00:28:18,079 Although millions die, millions more survive. 226 00:28:18,172 --> 00:28:21,237 And they ride the currents back to their nursery grounds, 227 00:28:21,319 --> 00:28:24,733 where, next year, they will rise again, 228 00:28:24,804 --> 00:28:29,054 as the greatest shoal on earth.