1 00:00:08,092 --> 00:00:09,635 BERTIE: We're looking for hammerheads, 2 00:00:10,470 --> 00:00:12,221 but we've had a surprise. 3 00:00:12,889 --> 00:00:14,348 -Can you see it, Hugh? -Yeah. 4 00:00:16,267 --> 00:00:18,144 BERTIE: A tiger shark has turned up. 5 00:00:21,939 --> 00:00:23,691 (SUSPENSEFUL MUSIC PLAYING) 6 00:00:23,858 --> 00:00:25,026 Well, the first rule 7 00:00:26,110 --> 00:00:27,779 is to always look behind you. 8 00:00:29,530 --> 00:00:31,282 Whoa, whoa! Tiger, tiger. 9 00:00:35,203 --> 00:00:38,039 Whoa! That has really fired up the sharks. 10 00:00:38,873 --> 00:00:41,167 Now they are just blasting around. 11 00:00:42,794 --> 00:00:45,546 My adrenaline is just pumping. 12 00:00:45,922 --> 00:00:47,632 (MUSIC CONTINUES) 13 00:00:48,758 --> 00:00:49,842 (MUSIC ENDS) 14 00:00:55,014 --> 00:00:55,890 -(THEME MUSIC BEGINS) -You ready? 15 00:00:56,140 --> 00:00:59,644 BERTIE: I'm Bertie. Filming animals is my job. 16 00:00:59,769 --> 00:01:01,437 That is not a chase you see every day. 17 00:01:01,521 --> 00:01:04,023 BERTIE: And I take it really seriously! 18 00:01:04,148 --> 00:01:05,525 Look, I'm trying to film penguins. 19 00:01:05,733 --> 00:01:07,485 -(GROWLS) -Oh, and I've missed it. 20 00:01:09,529 --> 00:01:10,988 Well, that was quite close. 21 00:01:12,073 --> 00:01:13,783 BERTIE: I want to tell wildlife stories 22 00:01:14,700 --> 00:01:16,369 in a rapidly changing world. 23 00:01:17,078 --> 00:01:19,205 That sounded like a big crack! 24 00:01:20,164 --> 00:01:20,998 (GASPS) 25 00:01:22,625 --> 00:01:24,585 BERTIE: These are my adventures. 26 00:01:26,045 --> 00:01:27,880 (THEME MUSIC ENDS) 27 00:01:29,924 --> 00:01:32,093 BERTIE: I'm traveling from my home in England 28 00:01:32,301 --> 00:01:34,345 to a shark-filled paradise, 29 00:01:34,762 --> 00:01:36,556 off the coast of Costa Rica. 30 00:01:40,226 --> 00:01:44,480 And our next stop is about 350 miles to the west. 31 00:01:45,189 --> 00:01:47,483 BERTIE: A tiny dot in the middle of the Pacific: 32 00:01:48,359 --> 00:01:49,902 Cocos Island. 33 00:01:50,653 --> 00:01:53,072 I'm just a little bit excited because it's a place 34 00:01:53,156 --> 00:01:55,908 that I've wanted to go for a very, very long time. 35 00:01:56,075 --> 00:01:57,952 It's the sharkiest place on Earth. 36 00:01:59,370 --> 00:02:01,289 BERTIE: After 36 hours at sea, 37 00:02:01,664 --> 00:02:03,166 we've finally made it! 38 00:02:03,374 --> 00:02:04,750 (BIRDS SQUAWKING) 39 00:02:09,046 --> 00:02:11,174 BERTIE: Cocos is a shark magnet, 40 00:02:11,507 --> 00:02:13,885 attracting 14 different species. 41 00:02:14,719 --> 00:02:17,597 The best shark spectacle here is the hammerhead. 42 00:02:17,847 --> 00:02:20,641 They gather here in mega schools. 43 00:02:21,184 --> 00:02:24,395 But with global shark and ray numbers in freefall - 44 00:02:24,604 --> 00:02:27,690 70 percent have been wiped out in just 50 years - 45 00:02:28,399 --> 00:02:32,403 Cocos is one of the last places left to find them in such numbers. 46 00:02:33,821 --> 00:02:36,240 Sharks are in a race against time, 47 00:02:37,408 --> 00:02:38,451 and so am I. 48 00:02:39,952 --> 00:02:43,706 Because Cocos is a marine reserve, I've got just 12 days 49 00:02:43,789 --> 00:02:48,461 to find a giant school of hammerheads in some of the most dangerous waters 50 00:02:48,544 --> 00:02:50,338 for diving in the world. 51 00:02:50,963 --> 00:02:52,757 This is gonna be tough, 52 00:02:54,425 --> 00:02:55,843 but I love a challenge. 53 00:02:58,971 --> 00:03:00,014 Everyone ready? 54 00:03:00,348 --> 00:03:01,766 Okay. Here we go. 55 00:03:02,058 --> 00:03:04,018 Right, so whenever I go somewhere new, 56 00:03:04,143 --> 00:03:07,188 I like to chuck the drone up to get a lay of the land. 57 00:03:09,565 --> 00:03:11,943 (DRAMATIC MUSIC PLAYING) 58 00:03:13,861 --> 00:03:16,113 (BIRDS SQUAWKING) 59 00:03:16,614 --> 00:03:18,199 BERTIE: Oh, that is amazing. 60 00:03:18,991 --> 00:03:21,744 (BIDS SQUAWKING) 61 00:03:22,078 --> 00:03:26,582 BERTIE: So Cocos is the tip of a huge underwater volcano 62 00:03:26,749 --> 00:03:29,627 that erupted two million years ago. 63 00:03:31,837 --> 00:03:35,132 And those cliffs there, they plummet into the dark waters, 64 00:03:35,216 --> 00:03:37,301 over two miles down... 65 00:03:39,887 --> 00:03:44,100 and when ferocious currents smash into these rock walls, 66 00:03:44,267 --> 00:03:49,563 they force up food from the deep, making Cocos irresistible to sharks... 67 00:03:53,192 --> 00:03:56,654 but a nightmare for divers. 68 00:03:59,031 --> 00:04:00,783 (MUSIC ENDS) 69 00:04:02,118 --> 00:04:04,829 BERTIE: Before I get underwater, I need a plan. 70 00:04:10,793 --> 00:04:13,337 So this is our home for the next couple of weeks: 71 00:04:15,131 --> 00:04:16,173 Sharkwater. 72 00:04:19,302 --> 00:04:23,848 She's a 130-foot specialist shark research vessel 73 00:04:23,973 --> 00:04:27,560 that has all of our food, equipment, and medical gear 74 00:04:27,643 --> 00:04:31,772 to keep our film crew, divers, and scientists alive. 75 00:04:33,524 --> 00:04:36,944 We're a long way from home, so she is our lifeline. 76 00:04:40,990 --> 00:04:44,493 To help me with the mission, I've brought an epic team along. 77 00:04:45,536 --> 00:04:46,912 We're here to film sharks. 78 00:04:46,996 --> 00:04:49,999 BERTIE: Hugh's been making underwater films for nearly thirty years. 79 00:04:50,374 --> 00:04:52,835 His job is to keep divers alive. 80 00:04:53,252 --> 00:04:55,629 Lost divers. You know, people do get swept away. 81 00:04:55,755 --> 00:04:56,881 The currents here are furious. 82 00:04:57,006 --> 00:04:59,633 BERTIE: Cristiano's been a legendary safety diver here 83 00:04:59,800 --> 00:05:01,260 for over two decades. 84 00:05:01,385 --> 00:05:02,845 Never dive by yourself. 85 00:05:02,970 --> 00:05:05,639 Once we're ready to go up, we all go up together. 86 00:05:05,848 --> 00:05:06,891 We're on our own here. 87 00:05:07,058 --> 00:05:09,268 If there's an accident, there's going to be big trouble. 88 00:05:10,728 --> 00:05:13,189 So what Hugh's saying is, it's all bad news. 89 00:05:14,482 --> 00:05:16,025 No, we just need to be sensible! 90 00:05:16,359 --> 00:05:19,737 This is why we take grown-ups on shoots because they look after us. 91 00:05:20,196 --> 00:05:21,822 (AIR WHOOSHES) 92 00:05:22,239 --> 00:05:24,116 BERTIE: We've also got to make sure our equipment 93 00:05:24,283 --> 00:05:25,659 is in the best working order. 94 00:05:26,494 --> 00:05:30,456 Yeah, there is no room for any mistakes in these sketchy waters. 95 00:05:31,791 --> 00:05:34,085 Now, we're starting with basic scuba. 96 00:05:34,627 --> 00:05:37,338 It's quick to set up and I've got a special face mask, 97 00:05:37,671 --> 00:05:42,176 so unfortunately there is no escaping seeing and hearing me at all times. 98 00:05:42,676 --> 00:05:43,552 Ready to go. 99 00:05:45,513 --> 00:05:49,350 BERTIE: Sharkwater is moored here, in this sheltered bay. 100 00:05:51,936 --> 00:05:54,563 We're gonna travel to the tip of a submerged mountain, 101 00:05:54,688 --> 00:05:56,524 about a mile from the mainland. 102 00:05:57,066 --> 00:05:57,983 Just here. 103 00:05:58,859 --> 00:06:00,986 I'm gonna call it Seamount. 104 00:06:01,654 --> 00:06:03,989 It's renowned as a hammerhead hotspot. 105 00:06:05,241 --> 00:06:07,535 Okay, let's see if we can find some sharkies. 106 00:06:07,827 --> 00:06:10,246 (DRAMATIC MUSIC PLAYING) 107 00:06:24,718 --> 00:06:25,845 (MUSIC ENDS) 108 00:06:34,103 --> 00:06:38,065 You can see this current is just pumping. I'm barely kicking. 109 00:06:38,858 --> 00:06:40,443 And we're just zooming along. 110 00:06:41,694 --> 00:06:44,530 This current's... really got a hold of me. 111 00:06:45,114 --> 00:06:46,866 I'm only going in one direction. 112 00:06:47,783 --> 00:06:49,577 I am not swimming against this. 113 00:06:55,708 --> 00:07:00,463 Jagged rocks, spiky sea urchins. It's an underwater minefield! 114 00:07:03,090 --> 00:07:05,468 And I am getting slammed around. 115 00:07:09,638 --> 00:07:13,225 If I hit this reef, it is gonna shred my wetsuit. 116 00:07:13,934 --> 00:07:17,396 And I, uh... I don't wanna touch the marine life, either. 117 00:07:20,316 --> 00:07:24,528 It's, uh... It's impossible to control where I'm going... 118 00:07:25,821 --> 00:07:27,573 and what my camera's doing. 119 00:07:28,240 --> 00:07:31,118 If that gets smashed, I'm in big trouble. 120 00:07:32,578 --> 00:07:34,079 I could be swept away. 121 00:07:34,830 --> 00:07:37,374 Next stop: Philippines. 122 00:07:38,667 --> 00:07:41,086 BERTIE: If I come up just 50 feet from the boat, 123 00:07:41,253 --> 00:07:43,214 the safety team will never spot me. 124 00:07:43,631 --> 00:07:44,590 I'll be gone. 125 00:07:45,341 --> 00:07:47,927 This has been a real eye-opener. 126 00:07:48,761 --> 00:07:50,679 I think we're going to need a different approach. 127 00:07:55,976 --> 00:07:59,271 BERTIE: For our first dive, those currents were impossible 128 00:07:59,522 --> 00:08:01,899 so we're leaving the Seamount and going round 129 00:08:02,024 --> 00:08:03,484 to the other side of the island. 130 00:08:05,736 --> 00:08:09,573 Wow, those waterfalls are amazing. 131 00:08:10,157 --> 00:08:13,118 You can see why pirates came all the way to Cocos 132 00:08:13,285 --> 00:08:14,995 to stock up on fresh water 133 00:08:16,121 --> 00:08:17,456 and hide their treasure. 134 00:08:20,251 --> 00:08:22,419 On this side of the island there's a drop off. 135 00:08:23,629 --> 00:08:28,050 It's a cliff edge which plunges nearly two miles down to the ocean floor. 136 00:08:28,884 --> 00:08:31,387 Here we could get better protection from the currents. 137 00:08:38,394 --> 00:08:40,563 Well, it's way calmer here at the moment. 138 00:08:41,397 --> 00:08:43,774 But there's something really odd happening. 139 00:08:45,776 --> 00:08:48,737 It looks like a weird desert heat haze. 140 00:08:49,321 --> 00:08:52,366 It's hard to believe I'm in the same ocean. 141 00:08:53,117 --> 00:08:57,079 Well, I was just thinking I can't focus the camera today, 142 00:08:57,413 --> 00:09:01,792 but I've just realized fortunately it's not me, it's the thermocline. 143 00:09:03,168 --> 00:09:08,465 It's happening because ocean currents are smashing into the deep sides 144 00:09:08,632 --> 00:09:09,592 of Cocos, 145 00:09:10,467 --> 00:09:13,012 forcing cold water up from the deep 146 00:09:13,804 --> 00:09:19,685 where it hits warmer water, creating this strange shimmering effect. 147 00:09:20,894 --> 00:09:23,272 It's the most extreme one I've ever seen. 148 00:09:24,940 --> 00:09:27,735 And it might push the sharks up from the deep. 149 00:09:29,403 --> 00:09:31,155 Oh, look, our first hammerhead! 150 00:09:32,323 --> 00:09:35,451 Whoa! Oh, my! 151 00:09:44,335 --> 00:09:46,378 That is just... 152 00:09:47,630 --> 00:09:49,256 madness. 153 00:09:53,385 --> 00:09:56,847 I've been obsessed with these guys since I was a little kid. 154 00:09:58,557 --> 00:10:00,809 They are just so bizarre. 155 00:10:02,394 --> 00:10:05,105 They totally look like real-life aliens. 156 00:10:06,774 --> 00:10:09,151 And, man, does it look cool filming the sharks 157 00:10:09,276 --> 00:10:11,445 through the thermocline, through the haze. 158 00:10:16,075 --> 00:10:18,577 I can't get a really good look, though. 159 00:10:19,370 --> 00:10:21,080 It's just too distorted. 160 00:10:32,800 --> 00:10:35,469 Well, it looks like the thermocline might be gone. 161 00:10:36,011 --> 00:10:39,640 But, the... the hammerheads have done a disappearing act, too. 162 00:10:40,849 --> 00:10:42,351 They're just like ghosts. 163 00:10:45,354 --> 00:10:47,189 I mean, I guess at least it's given us 164 00:10:48,273 --> 00:10:51,360 a tantalizing little taste of what we might see. 165 00:10:53,987 --> 00:10:55,948 So cool to be around them. 166 00:10:57,032 --> 00:11:00,160 And, yeah, oh, it's not scary. It's just... 167 00:11:00,994 --> 00:11:02,371 awe-inspiring. 168 00:11:04,832 --> 00:11:06,750 We're going to have to keep looking. 169 00:11:09,211 --> 00:11:11,630 (BIRDS SQUAWKING) 170 00:11:12,840 --> 00:11:15,551 BERTIE: Two locations. Limited results. 171 00:11:15,968 --> 00:11:19,763 We still have time, but so far, not a lot is working. 172 00:11:20,681 --> 00:11:23,976 So we're moving sites again and carrying on the search. 173 00:11:27,229 --> 00:11:29,106 Well, even this drone isn't helping; 174 00:11:29,273 --> 00:11:32,067 the sharks are just too deep to see from the surface. 175 00:11:34,862 --> 00:11:36,447 -(BLOWS RASPBERRY) -BERTIE: And a tickly nose, 176 00:11:36,822 --> 00:11:38,198 not helpful either. 177 00:11:39,616 --> 00:11:41,452 Sometimes with both hands occupied... 178 00:11:41,618 --> 00:11:42,494 Thank you. 179 00:11:43,120 --> 00:11:45,038 BERTIE: ...you need a little extra assistance. 180 00:11:45,539 --> 00:11:47,499 (CHUCKLES) I had a fly on my nose. 181 00:11:48,292 --> 00:11:50,878 (BIRDS SQUAWKING) 182 00:11:59,344 --> 00:12:01,263 Hang on, we might have something here. 183 00:12:03,015 --> 00:12:04,057 (WATER BLOWS) 184 00:12:04,725 --> 00:12:06,393 BERTIE: Just get a better position. 185 00:12:11,732 --> 00:12:13,108 That is a humpback whale. 186 00:12:14,985 --> 00:12:16,111 (CHUCKLES) 187 00:12:20,949 --> 00:12:23,160 There's a calf. There's a calf. It's a mum and calf. 188 00:12:30,250 --> 00:12:32,377 Oh, it's so cute! It's tiny. 189 00:12:34,838 --> 00:12:36,757 There's dolphins on its bow. 190 00:12:41,178 --> 00:12:43,472 Female humpback whale and a calf, 191 00:12:43,889 --> 00:12:45,474 dolphins on its nose. 192 00:12:49,603 --> 00:12:50,938 Oh, that is amazing. 193 00:12:54,441 --> 00:12:56,485 So easy to get distracted around here. 194 00:13:08,330 --> 00:13:09,456 BERTIE: It's Day 5, 195 00:13:09,832 --> 00:13:12,459 and we've been here nearly half our time already. 196 00:13:13,043 --> 00:13:17,089 We've barely seen a hammerhead, let alone huge numbers of them. 197 00:13:20,717 --> 00:13:23,846 There's another trick to finding sharks here at Cocos. 198 00:13:28,642 --> 00:13:32,187 On every dive, I've kept my eye out for a special little fish 199 00:13:32,479 --> 00:13:35,983 that can sometimes be a sign that sharks are nearby. 200 00:13:36,775 --> 00:13:39,778 It cleans the sharks, picking off their parasites 201 00:13:39,903 --> 00:13:41,154 to keep them healthy. 202 00:13:41,613 --> 00:13:45,117 Find these fish, and we could find the sharks. 203 00:13:45,284 --> 00:13:48,370 Let's just check out over this little ridge here. 204 00:13:52,666 --> 00:13:53,876 There they are! 205 00:13:56,587 --> 00:13:59,548 I can see these beautiful little yellow barber fish. 206 00:14:00,716 --> 00:14:04,094 They set up above the reef a cleaning station. 207 00:14:05,053 --> 00:14:07,598 The station's only a few feet in size, 208 00:14:08,098 --> 00:14:10,100 and all sorts of fish are coming in 209 00:14:10,225 --> 00:14:11,810 to get their parasites removed. 210 00:14:13,312 --> 00:14:14,980 Look, there's a rainbow runner. 211 00:14:16,773 --> 00:14:19,610 I love how... how delicate the barbers are! 212 00:14:20,485 --> 00:14:21,904 Hello, are you going to clean me? 213 00:14:24,197 --> 00:14:25,324 (CHUCKLES) 214 00:14:32,581 --> 00:14:33,498 Whoa! 215 00:14:35,667 --> 00:14:37,377 Check out these guys. 216 00:14:45,636 --> 00:14:47,638 These are Galapagos sharks. 217 00:14:48,221 --> 00:14:51,141 And they are chunky. 218 00:14:58,065 --> 00:15:01,234 Whoa! There's four or five... six, seven. (CHUCKLES) 219 00:15:06,907 --> 00:15:07,824 Hey buddy! 220 00:15:10,619 --> 00:15:14,289 They are way more interested in me than getting cleaned today. 221 00:15:16,041 --> 00:15:19,795 They're bold and they're curious, just checking us out. 222 00:15:22,339 --> 00:15:23,882 They're just doing their thing. 223 00:15:26,218 --> 00:15:27,594 Awesome animals. 224 00:15:35,477 --> 00:15:36,603 Look, hammerhead! 225 00:15:42,150 --> 00:15:45,112 That hammer is so identifiable. 226 00:15:54,371 --> 00:15:58,500 It's incredible, finally, to get a proper look through clear water. 227 00:16:03,005 --> 00:16:07,509 They're called the scalloped hammerhead. The front of their hammer isn't flat. 228 00:16:07,634 --> 00:16:09,803 It's these rounded scallop shapes. 229 00:16:14,349 --> 00:16:18,645 That amazing hammer shape helps spread out their senses. 230 00:16:21,690 --> 00:16:24,234 It moves their eyes a little further apart, 231 00:16:24,359 --> 00:16:27,821 so they can see 360 degrees right round. 232 00:16:30,532 --> 00:16:34,536 These guys are just one of ten hammerhead species worldwide. 233 00:16:39,249 --> 00:16:41,793 Let's just sit here and see if they come any closer. 234 00:16:49,134 --> 00:16:51,720 They just keep turning away right at the last minute. 235 00:16:54,556 --> 00:16:56,683 Hammerheads have got an extra sense, 236 00:16:57,142 --> 00:16:58,810 a real-life superpower, 237 00:16:59,561 --> 00:17:02,397 because they can sense electricity. 238 00:17:04,900 --> 00:17:10,322 All sharks can do this, but hammerheads seem particularly sensitive... 239 00:17:11,031 --> 00:17:13,241 because just like their other senses, 240 00:17:13,492 --> 00:17:16,703 that wide head spreads out the electroreceptors. 241 00:17:19,456 --> 00:17:24,377 Whenever we move a muscle, we tense an arm, or our heart beats, 242 00:17:24,795 --> 00:17:27,547 it gives off an electric field that they can detect. 243 00:17:29,007 --> 00:17:31,551 There's a hammerhead down on the sand down there. 244 00:17:33,261 --> 00:17:36,681 And that's really good for them for detecting prey in the dark. 245 00:17:37,015 --> 00:17:39,768 But it's tough for us 'cause getting close to them 246 00:17:39,851 --> 00:17:41,436 is gonna be a real challenge. 247 00:17:49,820 --> 00:17:51,154 Well, it seems like the hammers 248 00:17:51,279 --> 00:17:53,824 have moved away from the cleaning station out there 249 00:17:54,116 --> 00:17:55,117 into the blue. 250 00:17:56,952 --> 00:17:58,829 Current seems doable... 251 00:18:05,585 --> 00:18:06,837 Whoa! There they are. 252 00:18:09,673 --> 00:18:12,092 That is just so cool! 253 00:18:19,015 --> 00:18:21,351 Whoa! (CHUCKLES) 254 00:18:22,102 --> 00:18:23,270 This is crazy. 255 00:18:25,814 --> 00:18:29,109 These guys are called bigeye jacks. 256 00:18:30,735 --> 00:18:34,531 And there's no prizes for guessing why they're called bigeye jacks. 257 00:18:35,615 --> 00:18:38,869 That massive eye. That's 'cause they're nocturnal feeders. 258 00:18:38,952 --> 00:18:41,538 They hunt by themselves at night for little fish. 259 00:18:42,914 --> 00:18:46,209 They come together in these schools in the day 260 00:18:46,293 --> 00:18:49,087 for protection from their normal predators. 261 00:18:49,171 --> 00:18:53,175 The problem is it doesn't protect them against humans, 262 00:18:53,383 --> 00:18:55,635 the most dangerous predator on the planet. 263 00:19:00,473 --> 00:19:01,558 There are so many! 264 00:19:02,309 --> 00:19:04,519 Seeing this many of them together 265 00:19:05,687 --> 00:19:09,274 is like getting in a time machine 266 00:19:09,357 --> 00:19:12,736 and seeing what our oceans used to be like. 267 00:19:15,822 --> 00:19:16,865 Here they come! 268 00:19:33,965 --> 00:19:39,012 You know, this is evidence that protected areas work. 269 00:19:51,107 --> 00:19:52,400 Hammerhead! 270 00:19:58,615 --> 00:20:02,577 Every time a shark's been coming in, the jacks are using its skin, 271 00:20:02,786 --> 00:20:04,537 its rough skin, as a scratching post. 272 00:20:06,790 --> 00:20:09,292 You know, I don't know why the sharks don't just spin around 273 00:20:09,417 --> 00:20:11,670 and eat the jacks. They just run away. 274 00:20:13,630 --> 00:20:16,466 Those jacks have messed up our plans this time, 275 00:20:16,549 --> 00:20:18,802 but the cleaning station's definitely 276 00:20:18,927 --> 00:20:20,220 a good place to hang out. 277 00:20:21,179 --> 00:20:24,015 I know that the hammerheads are gonna turn up here eventually. 278 00:20:25,392 --> 00:20:27,352 Although they're so sensitive, 279 00:20:27,811 --> 00:20:29,729 I think we're just gonna have to be patient. 280 00:20:34,025 --> 00:20:36,403 BERTIE: Over the next three days we keep diving... 281 00:20:39,823 --> 00:20:41,574 but the hammers are like phantoms. 282 00:20:44,244 --> 00:20:46,371 And the moment they're coming straight down the barrel 283 00:20:46,454 --> 00:20:48,373 and you think you've got them, and you're like, "Yes!", 284 00:20:48,623 --> 00:20:50,959 they then turn and go away and... "Ah, come on!" 285 00:20:53,753 --> 00:20:56,172 BERTIE: We just don't seem to be able to crack it. 286 00:20:59,676 --> 00:21:01,136 And then on Day 9, 287 00:21:02,971 --> 00:21:06,266 something happens that stops our mission in its tracks. 288 00:21:06,975 --> 00:21:10,937 Our producer James spots a shark with a fearsome reputation, 289 00:21:13,440 --> 00:21:17,235 the type that killed someone right here, just a few years ago. 290 00:21:19,070 --> 00:21:23,074 Time to get out, regroup, and come up with a new safety plan. 291 00:21:26,786 --> 00:21:30,040 Well, we were just coming up from a dive and all of a sudden, 292 00:21:30,498 --> 00:21:34,586 there were two very big tiger sharks, and what was weird 293 00:21:34,711 --> 00:21:36,838 was that they were by that island over there, 294 00:21:37,088 --> 00:21:40,675 and they were right at the surface, right up against the cliff. 295 00:21:40,967 --> 00:21:44,679 So I'm just putting together the drone, and I'm going to buzz it out there, 296 00:21:45,055 --> 00:21:46,681 see if we can figure out what's going on. 297 00:21:48,600 --> 00:21:52,354 Tiger sharks are the most deadly shark at Cocos. 298 00:21:53,188 --> 00:21:57,275 And worldwide, only the great white is more dangerous to humans. 299 00:21:58,777 --> 00:22:01,112 I want to work out what they're doing so we can carry on 300 00:22:01,321 --> 00:22:03,823 diving safely in this area. 301 00:22:04,407 --> 00:22:06,993 Well, there is our tiger shark. 302 00:22:08,620 --> 00:22:11,039 It's just cruising in that channel 303 00:22:11,122 --> 00:22:15,543 between the little islet of Manuelita and the main Cocos island. 304 00:22:16,419 --> 00:22:20,048 Its dorsal fin is breaking the surface. Whoa, that is amazing. 305 00:22:20,382 --> 00:22:23,385 (DRAMATIC MUSIC PLAYING) 306 00:22:29,099 --> 00:22:30,600 BERTIE: If they're on the surface like that, 307 00:22:30,767 --> 00:22:32,602 we can get underneath them safely 308 00:22:32,685 --> 00:22:34,145 and see what they're up to. 309 00:22:40,360 --> 00:22:42,570 It looks pretty ominous and moody right now. 310 00:22:43,988 --> 00:22:47,075 I guess I'm a little nervous about getting in the water with a tiger shark. 311 00:22:49,661 --> 00:22:53,164 (BIRDS SCREECHING) 312 00:22:54,958 --> 00:22:56,709 That's the noise of a little booby chick, 313 00:22:57,710 --> 00:23:00,046 getting fed. Sounds pretty happy about it. 314 00:23:03,591 --> 00:23:07,262 All over this cliff, there's little white fluffy balls, 315 00:23:07,512 --> 00:23:08,721 little booby chicks. 316 00:23:09,264 --> 00:23:13,309 And you can see now the parents, who've spent the day out at sea hunting, 317 00:23:13,685 --> 00:23:15,395 are now coming back to feed them. 318 00:23:16,062 --> 00:23:20,817 When they get the chance, tiger sharks are known for eating seabirds. 319 00:23:21,317 --> 00:23:24,362 They'll even patrol below nest sites. 320 00:23:25,530 --> 00:23:27,532 Could this be what's happening here? 321 00:23:29,200 --> 00:23:31,828 BERTIE: My plan is to drop in near the base of this cliff. 322 00:23:32,745 --> 00:23:35,665 I've positioned a sweep boat here to pick us up 323 00:23:35,790 --> 00:23:37,375 in case the currents take us, 324 00:23:38,084 --> 00:23:40,336 and an emergency evacuation boat here 325 00:23:40,670 --> 00:23:42,630 if we get into trouble with the tigers. 326 00:23:49,345 --> 00:23:52,348 We need to get in quickly, and get away from the surface 327 00:23:52,432 --> 00:23:54,517 where the tigers might mistake us for food. 328 00:23:55,185 --> 00:23:56,603 Okay. Here we go. (GRUNTS) 329 00:24:04,402 --> 00:24:07,655 Surface to Bertie, surface to Bertie. Comms check. 330 00:24:09,032 --> 00:24:11,784 BERTIE: Yeah, Zubin, I can hear you. Can you hear me? 331 00:24:12,452 --> 00:24:14,579 Thanks, Bertie. I hear you loud and clear. 332 00:24:14,996 --> 00:24:16,998 Roger that. Chat to you in a bit. 333 00:24:23,838 --> 00:24:27,258 Well, the first rule of looking for tiger sharks 334 00:24:28,468 --> 00:24:30,470 is to always look behind you. 335 00:24:31,679 --> 00:24:34,015 They love sneaking up behind things. 336 00:24:34,724 --> 00:24:38,102 So that's why I keep spinning round, checking over my shoulder. 337 00:24:42,732 --> 00:24:43,942 Let's just hold here. 338 00:25:03,920 --> 00:25:07,048 Must say it's a bit spooky. Whoa, whoa! Big... right here, right here. 339 00:25:07,382 --> 00:25:09,175 Tiger, tiger, tiger... 340 00:25:13,513 --> 00:25:16,599 Big ones can be 18 feet long. 341 00:25:18,059 --> 00:25:21,896 Pretty intimidating. They are a big, powerful predator. 342 00:25:25,233 --> 00:25:26,859 You know, they can grow to... 343 00:25:27,819 --> 00:25:29,445 2,000 pounds. 344 00:25:30,780 --> 00:25:33,575 Oh, but they are just so big. 345 00:25:35,493 --> 00:25:36,578 Whoa! 346 00:25:39,080 --> 00:25:42,875 Look at those stripes. That's how they get their name. 347 00:25:44,377 --> 00:25:48,047 There isn't a lot that isn't on the menu of these tiger sharks. 348 00:25:48,590 --> 00:25:52,802 Fish, turtles, whale carcasses. 349 00:25:53,261 --> 00:25:58,600 They've even found license plates inside the bellies of these tigers. 350 00:26:03,688 --> 00:26:04,772 Tiger, tiger! 351 00:26:14,282 --> 00:26:18,911 These sharks must just be waiting, right at the base of the cliff 352 00:26:19,704 --> 00:26:21,664 for any birds, chicks or adults, 353 00:26:22,540 --> 00:26:25,084 to land on the surface and then boom. 354 00:26:25,752 --> 00:26:28,588 That's not a mistake that the bird gets to make twice. 355 00:26:30,798 --> 00:26:33,426 These tigers are just so smart. 356 00:26:33,801 --> 00:26:38,222 That's the third one we've seen, and they're all doing the same thing. 357 00:26:40,391 --> 00:26:41,726 There's two tigers just here. 358 00:26:43,478 --> 00:26:45,730 BERTIE: I can see how these tigers behave. 359 00:26:47,315 --> 00:26:49,108 Whenever we're in this channel, 360 00:26:50,276 --> 00:26:53,946 we know we've got to stay deep, stay away from the surface, 361 00:26:55,490 --> 00:26:58,076 so no tiger mistakes us for a booby. 362 00:27:07,543 --> 00:27:11,297 Just as we saw on the drone, the tiger sharks are patrolling 363 00:27:11,547 --> 00:27:14,717 right at the surface, right in that surf zone. 364 00:27:15,510 --> 00:27:19,013 And I would not want to be one of those boobies up there. 365 00:27:19,389 --> 00:27:21,641 (BIRDS SQUAWKING) 366 00:27:24,268 --> 00:27:26,437 BERTIE: We've learnt to think like tiger sharks 367 00:27:26,521 --> 00:27:28,398 to keep us out of danger. 368 00:27:28,481 --> 00:27:32,652 And if we can think like hammerheads, we could find a giant school. 369 00:27:33,528 --> 00:27:36,948 (BIRDS SQUAWKING) 370 00:27:40,410 --> 00:27:41,536 BERTIE: I'm meeting a man 371 00:27:41,619 --> 00:27:43,955 who's already learned to think like a hammerhead 372 00:27:44,205 --> 00:27:45,540 so he can help save them. 373 00:27:47,375 --> 00:27:51,921 Cocos is a protected reserve, but when they leave this safety zone, 374 00:27:52,130 --> 00:27:54,549 they're getting annihilated by fishing boats. 375 00:27:56,134 --> 00:27:59,762 For 15 years, scientist Randall Arauz has been tagging them 376 00:27:59,846 --> 00:28:01,764 to track their movements across the Pacific. 377 00:28:02,849 --> 00:28:05,768 And where they go, he wants to protect. 378 00:28:06,728 --> 00:28:08,271 Randall, what's the plan? 379 00:28:08,646 --> 00:28:11,816 Well, the plan is to attach one of these tags onto a shark. 380 00:28:12,066 --> 00:28:13,985 So, what... this is going to go into the shark. 381 00:28:14,152 --> 00:28:15,570 And then, this detaches. 382 00:28:15,945 --> 00:28:18,156 So we're gonna see the shark hopefully swimming away 383 00:28:18,281 --> 00:28:19,699 with the tag flopping behind. 384 00:28:19,949 --> 00:28:22,702 Do you have any particular tactics for sneaking up on the sharks? 385 00:28:22,952 --> 00:28:25,329 So what you have to do is, you look for the cleaning station. 386 00:28:25,413 --> 00:28:27,290 And remember these hammerheads are very skittish. 387 00:28:27,457 --> 00:28:29,876 So any abrupt movement and they'll get scared. 388 00:28:30,001 --> 00:28:32,086 So just wait for it to come in. And once he's inside 389 00:28:32,253 --> 00:28:35,089 the cleaning station, getting cleaned, that's when we take our shot. 390 00:28:42,638 --> 00:28:46,517 BERTIE: Randall and his team have tagged nearly 200 hammerheads. 391 00:28:47,477 --> 00:28:51,314 He tracks them using a network of receivers, like this one, 392 00:28:51,564 --> 00:28:54,484 dotted all over the Eastern Tropical Pacific. 393 00:28:57,528 --> 00:29:01,449 I'm filming him as he tries to add one more to his tally 394 00:29:05,328 --> 00:29:06,913 And there's no time to lose. 395 00:29:12,210 --> 00:29:14,670 Whoa! That shark's got a hook in its mouth! 396 00:29:16,547 --> 00:29:21,010 That shows these sharks are roaming outside the protected area, 397 00:29:21,636 --> 00:29:24,555 and that's when they come into contact with this fishing gear. 398 00:29:26,599 --> 00:29:31,729 BERTIE: At Cocos in the last 20 years, around half the population has vanished. 399 00:29:33,815 --> 00:29:37,693 Worldwide, scalloped hammerheads are critically endangered. 400 00:29:39,195 --> 00:29:41,823 They are being fished out of existence. 401 00:29:46,661 --> 00:29:52,583 We kill more than 100 million sharks every year to cut their fins off 402 00:29:53,376 --> 00:29:54,752 and put them into soup. 403 00:29:55,753 --> 00:30:00,716 And if we continue the way we're going, shark species will go extinct. 404 00:30:04,262 --> 00:30:08,558 And these underwater ecosystems, they need sharks to thrive. 405 00:30:09,141 --> 00:30:13,229 You know, the sharks, the top predators, they keep this whole thing in balance. 406 00:30:28,160 --> 00:30:31,122 BERTIE: Seeing Randall at work, I realize his mission 407 00:30:31,330 --> 00:30:33,708 could be the last chance for these hammerheads. 408 00:30:41,549 --> 00:30:42,758 (BERTIE CHUCKLES) 409 00:30:43,426 --> 00:30:45,136 Absolute magic. 410 00:30:48,431 --> 00:30:52,435 BERTIE: Each tag is another step to help save these incredible animals. 411 00:30:59,817 --> 00:31:04,530 It's vital that hammerhead highways are made no-go zones for fishing boats. 412 00:31:09,660 --> 00:31:12,788 Oh, and I've got so excited, I'm about to run out of air. 413 00:31:13,331 --> 00:31:15,041 So I'd better go up to the surface. 414 00:31:17,418 --> 00:31:20,588 BERTIE: Randall knows what it takes to get close to hammerheads. 415 00:31:21,422 --> 00:31:24,967 I can see he's controlling his breathing to keep his bubbles 416 00:31:25,051 --> 00:31:26,469 and noise to a minimum. 417 00:31:27,345 --> 00:31:29,764 And his movements are slow and steady. 418 00:31:31,474 --> 00:31:35,269 He's made himself almost invisible so he doesn't spook 419 00:31:35,394 --> 00:31:37,229 these super-sensitive sharks. 420 00:31:39,815 --> 00:31:41,150 Yeah, you know, the problem with... 421 00:31:42,318 --> 00:31:44,111 this scuba system is... 422 00:31:45,112 --> 00:31:49,659 we can be as still and hidden in these rocks as we want, but... 423 00:31:51,285 --> 00:31:53,663 but still making so many bubbles, so... 424 00:31:55,081 --> 00:31:57,083 I think we might need a different plan. 425 00:32:04,173 --> 00:32:07,760 BERTIE: Until now, we've used scuba, which is quick to get ready 426 00:32:07,969 --> 00:32:11,222 and pretty safe, so is our "go-to" equipment. 427 00:32:12,723 --> 00:32:15,518 But we've also brought these: rebreathers. 428 00:32:17,103 --> 00:32:19,939 They take much longer to rig, and, if you set them up wrong, 429 00:32:20,022 --> 00:32:21,482 can be really dangerous. 430 00:32:23,275 --> 00:32:26,112 The upside is they don't produce bubbles. 431 00:32:27,571 --> 00:32:29,865 So it looks like we're going to need to switch to these 432 00:32:29,991 --> 00:32:32,034 if we want to get closer to these sharks. 433 00:32:37,873 --> 00:32:40,501 You can see how everyone's gone very quiet this morning. 434 00:32:41,377 --> 00:32:43,045 And that's 'cause with normal scuba gear, 435 00:32:43,921 --> 00:32:46,298 if you mess up your equipment setup, 436 00:32:47,008 --> 00:32:49,844 the consequences aren't that bad, whereas with rebreathers, 437 00:32:49,969 --> 00:32:53,514 they are serious. So, we've got lots of checklists 438 00:32:54,056 --> 00:32:55,975 to make sure we're... we're doing it right. 439 00:32:56,142 --> 00:32:58,602 But just got to take it a little more seriously. 440 00:33:03,649 --> 00:33:06,402 (LAUGHTER) 441 00:33:07,236 --> 00:33:10,322 As I said, everyone's taking it really seriously this morning. 442 00:33:15,453 --> 00:33:18,581 BERTIE: I think our best bet is to head back to the cleaning station. 443 00:33:25,004 --> 00:33:26,255 -Oxygen analyzed. -Yeah. 444 00:33:26,338 --> 00:33:28,632 BERTIE: Just a few final checks to run through first. 445 00:33:28,758 --> 00:33:31,260 MALE VOICE: Computer, electronics. Absorbent time remaining... 446 00:33:31,385 --> 00:33:32,261 SILVIO: Four hours. 447 00:33:45,566 --> 00:33:48,694 Those rocks down there look like a pretty good place to hide, 448 00:33:49,779 --> 00:33:51,781 so I'm gonna get down in amongst the rocks, 449 00:33:52,239 --> 00:33:55,451 chill out, and see if we can get the hammerheads to come to us. 450 00:34:03,000 --> 00:34:06,629 Your normal scuba diving equipment, you just don't get the time down here. 451 00:34:06,712 --> 00:34:08,506 You're just getting a little snapshot. 452 00:34:13,385 --> 00:34:15,262 You know, these things are tricky to set up, 453 00:34:15,346 --> 00:34:17,348 but they're just so good for filming. 454 00:34:18,057 --> 00:34:19,892 I can sit still down here for hours... 455 00:34:20,392 --> 00:34:21,435 in stealth mode! 456 00:34:26,232 --> 00:34:29,068 Everywhere I look, there's little dramas unfolding. 457 00:34:29,401 --> 00:34:32,154 There's a little damselfish that has hilarious little lips. 458 00:34:32,279 --> 00:34:36,408 It looks like it's got lipstick on, and it's just pecking away at the algae. 459 00:34:36,867 --> 00:34:39,787 (ETHEREAL MUSIC PLAYING) 460 00:34:52,258 --> 00:34:53,843 Okay, I think we could be in business. 461 00:34:54,385 --> 00:34:57,763 (MUSIC CONTINUES) 462 00:35:12,027 --> 00:35:14,738 BERTIE: It's time to be really, really quiet. It's coming this way. 463 00:35:15,656 --> 00:35:18,284 (MUSIC CONTINUES) 464 00:35:38,888 --> 00:35:41,557 Whoa! That was crazy! 465 00:35:41,932 --> 00:35:44,602 These rebreathers are an absolute game changer. 466 00:35:53,402 --> 00:35:55,654 BERTIE: Now I'm keeping still, with no bubbles... 467 00:35:56,155 --> 00:35:58,490 the two things that have given me away before 468 00:35:59,116 --> 00:36:00,993 So we're nearly invisible to them. 469 00:36:01,535 --> 00:36:05,998 For the first time, I'm close enough to see how they move, how they behave. 470 00:36:12,755 --> 00:36:16,175 It slowed right down, and they just roll on their side, 471 00:36:16,342 --> 00:36:17,468 opening up their bellies. 472 00:36:17,635 --> 00:36:20,512 It's almost like a dog asking for a little scratch. 473 00:36:22,014 --> 00:36:25,017 And then all the little barber fish come rushing out the reef, 474 00:36:25,184 --> 00:36:26,685 and they just start nibbling. 475 00:36:47,665 --> 00:36:49,833 (MUSIC ENDS) 476 00:36:50,876 --> 00:36:54,672 You see that female had a big scar just above its pectoral fin. 477 00:36:54,922 --> 00:36:56,006 Well, that's from mating. 478 00:36:57,132 --> 00:36:59,009 The males will come along, and when they're mating 479 00:36:59,093 --> 00:37:00,928 they'll bite their pectoral fin. 480 00:37:02,846 --> 00:37:04,265 And this is a great sign. 481 00:37:04,807 --> 00:37:07,434 It's thought that hammerheads come together in these schools 482 00:37:07,518 --> 00:37:08,560 to find a mate. 483 00:37:09,561 --> 00:37:12,815 Those scars right there are a clue that huge gatherings 484 00:37:12,940 --> 00:37:14,149 are probably here. 485 00:37:14,692 --> 00:37:16,151 I just haven't seen them yet. 486 00:37:21,532 --> 00:37:23,492 They're out there in the gloom somewhere. 487 00:37:25,744 --> 00:37:28,664 And we've only got one more day of diving to nail this. 488 00:37:29,873 --> 00:37:34,128 (DRAMATIC MUSIC PLAYING) 489 00:37:47,182 --> 00:37:48,642 Got to be able to see the sharks. 490 00:37:52,396 --> 00:37:54,273 BERTIE: It's our final day at Cocos. 491 00:37:56,400 --> 00:38:00,487 Our last chance to try and see if these giant schools still exist. 492 00:38:07,119 --> 00:38:08,495 (MUSIC ENDS) 493 00:38:15,252 --> 00:38:18,213 BERTIE: But as usual, Cocos is not gonna make it easy. 494 00:38:19,590 --> 00:38:21,425 Whoa, look up there! 495 00:38:24,845 --> 00:38:28,640 There's a huge school of skipjack tuna just ripping overhead. 496 00:38:29,475 --> 00:38:32,519 It's like watching a big flock of birds blasting over. 497 00:38:33,896 --> 00:38:36,690 And that has really fired up the sharks. 498 00:38:37,024 --> 00:38:40,110 (TENSE MUSIC PLAYING) 499 00:38:42,946 --> 00:38:47,284 They were just gliding around before, but now they are just blasting around. 500 00:38:49,328 --> 00:38:51,997 My adrenaline is just pumping! 501 00:38:54,666 --> 00:38:56,627 I wonder if they're putting the hammerheads off. 502 00:39:01,006 --> 00:39:02,174 (MUSIC ENDS) 503 00:39:02,299 --> 00:39:04,218 Come on. Patience. 504 00:39:06,887 --> 00:39:08,722 Just let it all calm down. 505 00:39:12,559 --> 00:39:16,188 (ETHEREAL MUSIC PLAYING) 506 00:39:18,440 --> 00:39:19,983 Oh my... 507 00:39:22,694 --> 00:39:25,489 That is just so epic! 508 00:39:31,412 --> 00:39:35,207 There's too many to count, and they're just swirling 'round. 509 00:39:38,001 --> 00:39:41,004 These giant schools do still exist. 510 00:39:43,507 --> 00:39:46,427 This is what makes Cocos Island special. 511 00:39:46,760 --> 00:39:49,430 There are not many places left on the planet 512 00:39:49,513 --> 00:39:52,266 where you can see this number of sharks together. 513 00:39:54,101 --> 00:39:58,063 But I wanna get in amongst that school to see what's going on. 514 00:39:58,564 --> 00:40:01,650 (MUSIC CONTINUES) 515 00:40:03,318 --> 00:40:05,195 The current's starting to build now. 516 00:40:10,200 --> 00:40:11,452 Right. Here we go. 517 00:40:12,411 --> 00:40:15,831 To infinity and beyond! 518 00:40:16,623 --> 00:40:20,127 (MUSIC CONTINUES) 519 00:40:39,980 --> 00:40:41,482 They're letting me in amongst them! 520 00:40:42,858 --> 00:40:47,237 And now I can see it's just a big, swirling dancefloor. 521 00:40:52,117 --> 00:40:55,996 On the outside, you can see males, the smaller males, darting in, 522 00:40:56,288 --> 00:40:59,208 trying to entice the big females away to mate. 523 00:41:01,919 --> 00:41:05,005 This right here is the start of the next generation. 524 00:41:09,635 --> 00:41:12,930 I've imagined this view in my head for years, 525 00:41:13,680 --> 00:41:17,976 but I did not think we'd actually get to see it in real life. 526 00:41:20,687 --> 00:41:23,357 BERTIE: It's the completion of a lifelong ambition. 527 00:41:26,860 --> 00:41:29,863 But if we don't stop fishing them and protect them 528 00:41:29,988 --> 00:41:32,324 once they leave the safe waters of Cocos, 529 00:41:33,075 --> 00:41:35,702 these ghosts of the ocean will disappear... 530 00:41:37,412 --> 00:41:38,288 forever. 531 00:41:43,168 --> 00:41:44,670 (MUSIC ENDS) 532 00:41:46,713 --> 00:41:47,714 (THEME MUSIC PLAYING) 533 00:41:47,839 --> 00:41:50,133 BERTIE: We know where sharks migrate near Cocos, 534 00:41:50,676 --> 00:41:52,052 and we know they're targeted 535 00:41:52,177 --> 00:41:55,305 by fishing fleets when they leave protected zones. 536 00:41:56,890 --> 00:42:00,352 Good news is that those zones are about to get bigger, 537 00:42:00,936 --> 00:42:04,648 but it might come too late for the shark Randall tagged in this film. 538 00:42:04,856 --> 00:42:08,443 Since October 2020, the shark moved around Cocos, 539 00:42:08,527 --> 00:42:11,029 but in December, the signal went dead. 540 00:42:13,282 --> 00:42:14,616 (THEME MUSIC ENDS)