1 00:00:31,000 --> 00:00:33,560 WHALE SINGS 2 00:00:36,200 --> 00:00:38,120 SINGING CONTINUES 3 00:00:38,120 --> 00:00:41,400 A male humpback whale singing 4 00:00:41,400 --> 00:00:45,240 as he hangs in the vast blue emptiness of the ocean. 5 00:00:45,240 --> 00:00:47,800 WHALE CALLS 6 00:00:49,960 --> 00:00:53,960 He's proclaiming his presence to females. 7 00:00:53,960 --> 00:00:58,520 WHALE SINGS 8 00:01:04,320 --> 00:01:06,360 If he gets a response, 9 00:01:06,360 --> 00:01:10,640 he will have solved a major problem faced by all animals 10 00:01:10,640 --> 00:01:12,400 that live in the ocean. 11 00:01:18,280 --> 00:01:22,320 How to find others who have to play the mating game in 12 00:01:22,320 --> 00:01:26,080 the largest and least-populated habitat on Earth. 13 00:01:48,600 --> 00:01:54,560 Every year, humpback whales leave their cold, rich feeding grounds 14 00:01:54,560 --> 00:01:58,880 and swim nearly 3,000 miles to assemble in Hawaii. 15 00:02:02,520 --> 00:02:05,840 These warm waters are a safe playground 16 00:02:05,840 --> 00:02:07,920 where mothers can give birth. 17 00:02:10,840 --> 00:02:13,840 Not all the females here have calves. 18 00:02:20,440 --> 00:02:24,720 This one is announcing that she is here to mate. 19 00:02:35,400 --> 00:02:37,480 WHALE CALLS 20 00:02:37,480 --> 00:02:41,880 It's the signal that the singing male has been waiting for. 21 00:02:47,840 --> 00:02:50,800 But he is not the only one who's heard it. 22 00:02:52,040 --> 00:02:53,800 He has rivals. 23 00:02:57,720 --> 00:03:01,120 This may be his only chance to mate this season. 24 00:03:05,200 --> 00:03:07,400 The female takes the lead... 25 00:03:16,040 --> 00:03:18,160 ..and the males chase after her. 26 00:03:32,560 --> 00:03:34,840 The more males she attracts, 27 00:03:34,840 --> 00:03:36,520 the greater her choice. 28 00:03:40,560 --> 00:03:44,200 There are now over 20 males chasing after her. 29 00:03:49,480 --> 00:03:53,360 They race to take pole position alongside her. 30 00:03:59,640 --> 00:04:02,320 Only the strongest are able to keep up. 31 00:04:15,160 --> 00:04:18,920 They bellow and blow huge curtains of bubbles 32 00:04:18,920 --> 00:04:20,800 to intimidate one another. 33 00:04:55,640 --> 00:04:57,680 She slows down - 34 00:04:57,680 --> 00:05:00,760 that forces her pursuers closer together. 35 00:05:08,240 --> 00:05:11,320 And the chase explodes into violence. 36 00:05:24,160 --> 00:05:28,120 The 35-tonne males barge into one another 37 00:05:28,120 --> 00:05:30,960 as they try to force their way to the front. 38 00:05:44,040 --> 00:05:47,480 A larger male pushes a rival aside. 39 00:06:00,760 --> 00:06:04,720 Then, without warning, she calls a halt. 40 00:06:18,200 --> 00:06:22,160 Fewer than half her suitors remain. 41 00:06:22,160 --> 00:06:25,440 They circle her, keeping their distance. 42 00:06:28,760 --> 00:06:31,360 All except one. 43 00:06:40,320 --> 00:06:43,840 She allows him to caress her. 44 00:06:54,200 --> 00:06:57,440 He has won the right to be her close escort, 45 00:06:57,440 --> 00:07:00,880 and he makes sure that the others stay back. 46 00:07:06,400 --> 00:07:09,720 Their mating game appears to be over. 47 00:07:17,160 --> 00:07:21,080 These intimate scenes have never been witnessed before. 48 00:07:26,120 --> 00:07:29,360 We still don't fully understand what is happening. 49 00:07:34,320 --> 00:07:37,400 She may have made her final choice. 50 00:07:42,240 --> 00:07:46,480 This may be just the first stage in a longer courtship. 51 00:07:55,880 --> 00:08:00,240 What is certain is that the most private moments of her life 52 00:08:00,240 --> 00:08:02,480 have yet to be documented. 53 00:08:05,760 --> 00:08:09,800 No-one has ever seen humpback whales mating. 54 00:08:23,080 --> 00:08:25,080 The world beneath the waves 55 00:08:25,080 --> 00:08:29,360 is one we ourselves can visit only fleetingly. 56 00:08:29,360 --> 00:08:32,680 And for us, it's still filled with mystery. 57 00:08:34,160 --> 00:08:39,000 But in a few special places where we can spend time below the surface, 58 00:08:39,000 --> 00:08:43,120 the secrets of the seas are, at last, being revealed. 59 00:08:46,240 --> 00:08:51,360 The mating game, indeed, all life began in the ocean. 60 00:08:52,440 --> 00:08:57,240 And still today, there is no place where it is more visible or 61 00:08:57,240 --> 00:09:00,640 more varied than on a coral reef. 62 00:09:02,040 --> 00:09:05,320 Creatures living here enjoy one of the most stable of 63 00:09:05,320 --> 00:09:07,280 all marine environments... 64 00:09:11,480 --> 00:09:15,640 ..and one that contains a diversity of species unequalled 65 00:09:15,640 --> 00:09:17,400 anywhere else on Earth. 66 00:09:28,200 --> 00:09:33,400 Here, it's nearly always the breeding season for something. 67 00:09:47,760 --> 00:09:50,760 The reef may look like paradise, 68 00:09:50,760 --> 00:09:53,560 but its beauty hides a violent side. 69 00:09:55,160 --> 00:09:59,560 One that determines the mating strategy of many reef fish. 70 00:10:02,640 --> 00:10:06,600 These bumphead parrotfish, over a metre long, 71 00:10:06,600 --> 00:10:10,720 are among the largest of the reef's permanent inhabitants. 72 00:10:19,440 --> 00:10:22,720 Despite their size, when it comes to breeding, 73 00:10:22,720 --> 00:10:27,840 bumpheads face the same problems as other, much smaller fish. 74 00:10:30,520 --> 00:10:34,120 Adult females release their tiny eggs into the water 75 00:10:34,120 --> 00:10:35,800 for the males to fertilise. 76 00:10:38,160 --> 00:10:41,720 But many other creatures are waiting for that to happen 77 00:10:41,720 --> 00:10:43,920 with arms and tentacles outstretched. 78 00:10:56,640 --> 00:11:01,280 For many reef inhabitants, fish eggs are excellent food. 79 00:11:09,440 --> 00:11:13,080 If the next generation of bumpheads is to survive, 80 00:11:13,080 --> 00:11:18,240 the adults must get away from the reef and out into the open ocean. 81 00:11:20,760 --> 00:11:25,640 The approach of a new moon provides the best conditions for doing so. 82 00:11:30,320 --> 00:11:34,680 The high tide creates powerful currents that sweep out to sea - 83 00:11:34,680 --> 00:11:36,600 exactly what the fish need. 84 00:11:38,320 --> 00:11:42,560 Bumpheads come from all the nearby reefs and assemble together 85 00:11:42,560 --> 00:11:45,440 in a super school 1,000 strong. 86 00:11:52,880 --> 00:11:54,880 They head into deep water, 87 00:11:54,880 --> 00:11:57,880 leaving the reef's egg-hungry creatures behind. 88 00:12:02,480 --> 00:12:07,800 Now, the males develop white faces and striped flanks - 89 00:12:07,800 --> 00:12:09,600 their breeding costume. 90 00:12:16,280 --> 00:12:21,400 The mating rush begins, and soon, each female is surrounded by males. 91 00:12:31,320 --> 00:12:35,640 As she releases her eggs, so the males eject their milt. 92 00:12:41,680 --> 00:12:45,920 The strong tide now ensures that the bumpheads' fertilised eggs 93 00:12:45,920 --> 00:12:49,160 are carried away from the dangers of the reef. 94 00:13:03,400 --> 00:13:06,160 It seems an excellent strategy. 95 00:13:06,160 --> 00:13:08,440 But it does have a flaw. 96 00:13:17,280 --> 00:13:21,520 Huge schools of fish inevitably attract predators. 97 00:13:25,400 --> 00:13:29,120 This solitary bull shark, however, is too late. 98 00:13:29,120 --> 00:13:31,480 The spawning rush has ended. 99 00:13:35,680 --> 00:13:40,600 But there are others for whom sharks present a far greater danger. 100 00:13:42,080 --> 00:13:45,920 These little striped fish are convict tangs. 101 00:13:48,440 --> 00:13:52,800 They, too, have gathered in huge schools to spawn - 102 00:13:52,800 --> 00:13:55,360 and they, too, must get away from the reef. 103 00:13:58,040 --> 00:14:01,320 But it's not just their eggs that are at risk. 104 00:14:02,920 --> 00:14:05,840 They have attracted grey reef sharks. 105 00:14:08,360 --> 00:14:10,120 Hundreds of them. 106 00:14:12,360 --> 00:14:15,960 With hungry sharks above them and predators of all kinds 107 00:14:15,960 --> 00:14:19,000 lurking in the coral, the tangs are trapped. 108 00:14:29,040 --> 00:14:31,000 These convicts have an escape plan. 109 00:14:34,760 --> 00:14:36,720 The first to spawn 110 00:14:36,720 --> 00:14:39,280 attract the attention of the sharks. 111 00:14:47,080 --> 00:14:51,160 The moment the sharks attack one spawning party, 112 00:14:51,160 --> 00:14:52,960 another takes its chance. 113 00:15:08,000 --> 00:15:11,280 The more tangs that join in, 114 00:15:11,280 --> 00:15:13,800 the greater the confusion. 115 00:15:27,840 --> 00:15:32,360 In the dazzle of flashing stripes and swirling clouds of spawn, 116 00:15:32,360 --> 00:15:36,480 the sharks find it difficult to select individual victims. 117 00:15:50,360 --> 00:15:52,560 The spawning tactic has worked. 118 00:15:53,960 --> 00:15:59,200 The sharks go hungry, and billions of tiny fertilised eggs drift away 119 00:15:59,200 --> 00:16:00,200 from the reef. 120 00:16:04,080 --> 00:16:07,320 But in the open seas, there are other dangers. 121 00:16:12,040 --> 00:16:16,440 A manta ray is waiting with its huge mouth open wide. 122 00:16:19,880 --> 00:16:21,960 And this female is not alone. 123 00:16:24,720 --> 00:16:29,520 Mantas are among the most social and intelligent of fish, 124 00:16:29,520 --> 00:16:33,920 and they're very skilled at finding the floating eggs and other tiny 125 00:16:33,920 --> 00:16:36,000 organisms on which they feed. 126 00:16:39,320 --> 00:16:42,640 When food is scarce, they swim in small groups. 127 00:16:45,960 --> 00:16:49,920 But where the currents create a really rich soup, mantas gather 128 00:16:49,920 --> 00:16:51,280 in immense numbers. 129 00:17:01,160 --> 00:17:04,480 Over 150 have found this particular feast. 130 00:17:19,520 --> 00:17:23,480 An assembly like this one is rare, but when it happens, 131 00:17:23,480 --> 00:17:27,760 the mantas produce one of the most graceful ballets 132 00:17:27,760 --> 00:17:30,480 to be seen anywhere in any ocean. 133 00:18:05,120 --> 00:18:09,040 Despite their numbers, there is more food here than the mantas 134 00:18:09,040 --> 00:18:10,400 themselves can eat. 135 00:18:13,160 --> 00:18:16,480 Only when the surviving eggs have developed into tiny fish 136 00:18:16,480 --> 00:18:20,760 that can actively swim, will they make their way to the reef. 137 00:18:24,600 --> 00:18:27,840 But not all of the reef's inhabitants are able to leave 138 00:18:27,840 --> 00:18:29,120 in order to breed. 139 00:18:32,480 --> 00:18:35,720 And those that stay here have developed some of the most 140 00:18:35,720 --> 00:18:38,240 ingenious mating strategies of all. 141 00:18:41,360 --> 00:18:44,000 This is one of the commonest and most familiar 142 00:18:44,000 --> 00:18:47,240 of the reef's permanent inhabitants. 143 00:18:47,240 --> 00:18:48,720 A clownfish. 144 00:18:50,600 --> 00:18:53,160 She spends most of her time surrounded 145 00:18:53,160 --> 00:18:56,320 by the writhing tentacles of a giant anemone. 146 00:19:02,680 --> 00:19:05,280 She is head of a family. 147 00:19:05,280 --> 00:19:07,280 And the biggest of them all. 148 00:19:10,200 --> 00:19:14,840 Her family is growing fast with well-cared for young, 149 00:19:14,840 --> 00:19:16,640 who are clearly thriving. 150 00:19:24,360 --> 00:19:26,280 What could be more perfect? 151 00:19:28,520 --> 00:19:30,520 But all is not as it seems. 152 00:19:33,160 --> 00:19:37,480 As the largest in the family, she is clearly in charge. 153 00:19:37,480 --> 00:19:39,200 But it wasn't always so. 154 00:19:41,400 --> 00:19:45,840 Before she became head of this family, SHE was a HE. 155 00:19:47,880 --> 00:19:51,240 It was the disappearance of the previous ruling female 156 00:19:51,240 --> 00:19:53,680 that triggered this change of sex. 157 00:19:57,480 --> 00:20:00,280 This middle sized fish is a male - 158 00:20:00,280 --> 00:20:06,120 her breeding partner - but he is only biding his time, waiting 159 00:20:06,120 --> 00:20:10,600 for the moment when, for one reason or another, she disappears. 160 00:20:11,840 --> 00:20:15,720 Then it will be his chance to turn into a female and become 161 00:20:15,720 --> 00:20:17,640 the new head of the family. 162 00:20:21,280 --> 00:20:24,960 The smallest fish is a newcomer, a male, the lowest 163 00:20:24,960 --> 00:20:26,880 in this line of succession. 164 00:20:29,520 --> 00:20:32,400 While he remains small, he will not mate. 165 00:20:35,760 --> 00:20:38,520 The dominant pair want to maintain their rule 166 00:20:38,520 --> 00:20:40,640 and they constantly bully him. 167 00:20:46,280 --> 00:20:50,240 This stress produces hormones in his body, which prevents him 168 00:20:50,240 --> 00:20:54,280 from growing larger and upsetting the breeding hierarchy. 169 00:21:04,640 --> 00:21:08,640 So long as he sits third in line, his mating game 170 00:21:08,640 --> 00:21:12,760 is more of a waiting game, and it may be so for quite 171 00:21:12,760 --> 00:21:14,280 a while yet. 172 00:21:16,680 --> 00:21:20,560 She might rule her household for nearly 15 years. 173 00:21:27,960 --> 00:21:32,640 Changing sex is not uncommon on the reef, but there are others 174 00:21:32,640 --> 00:21:36,000 here who have even stranger breeding techniques. 175 00:21:41,920 --> 00:21:44,960 These flamboyant creatures are nudibranchs. 176 00:21:52,760 --> 00:21:57,440 Their vivid colours and elaborate patterns are certainly not ways 177 00:21:57,440 --> 00:22:01,480 of attracting the attention of the opposite sex, 178 00:22:01,480 --> 00:22:03,920 for nudibranchs are in fact blind. 179 00:22:08,760 --> 00:22:12,920 Their colours instead are warnings to predators that their bodies 180 00:22:12,920 --> 00:22:14,560 are packed with poison. 181 00:22:16,240 --> 00:22:17,240 So stay away. 182 00:22:22,240 --> 00:22:25,680 Since appearance is no help in bringing individuals together, 183 00:22:25,680 --> 00:22:29,760 they have to rely on scent or taste which, under water, 184 00:22:29,760 --> 00:22:31,960 is more or less the same thing. 185 00:22:37,320 --> 00:22:40,960 And they play a special version of the mating game. 186 00:22:49,440 --> 00:22:53,120 Nudibranchs are neither male nor female. 187 00:22:53,120 --> 00:22:55,240 They're both at the same time. 188 00:23:00,960 --> 00:23:05,280 So when they do find a partner, they neither fight nor flirt. 189 00:23:09,080 --> 00:23:13,320 They simply, peacefully and more or less simultaneously 190 00:23:13,320 --> 00:23:14,880 fertilise one another. 191 00:23:16,480 --> 00:23:19,360 If only it was always so straightforward. 192 00:23:25,280 --> 00:23:26,640 This is a flatworm. 193 00:23:29,640 --> 00:23:35,080 Flatworms, like nudibranchs, are also both male and female and blind, 194 00:23:35,080 --> 00:23:37,360 finding their way by smell. 195 00:23:38,400 --> 00:23:41,080 But that is where the similarity ends. 196 00:23:43,000 --> 00:23:46,920 This one called the Persian carpet flatworm because of the elaborate 197 00:23:46,920 --> 00:23:49,480 patterning, is a voracious predator. 198 00:23:58,480 --> 00:24:02,720 And when it comes to mating, it's also somewhat aggressive. 199 00:24:04,280 --> 00:24:08,440 It has sensed the presence of another flatworm, 200 00:24:08,440 --> 00:24:10,320 a potential partner. 201 00:24:17,240 --> 00:24:22,800 To start with, they seem wary of one another, 202 00:24:22,800 --> 00:24:24,600 and with good reason. 203 00:24:29,240 --> 00:24:32,200 Each of them is trying to avoid the labour of looking 204 00:24:32,200 --> 00:24:34,040 after the fertilised eggs. 205 00:24:35,120 --> 00:24:37,600 It's better not to become pregnant. 206 00:24:41,120 --> 00:24:44,840 Rearing up, each reveals its two-pronged penis. 207 00:24:53,200 --> 00:24:54,560 And now they fence. 208 00:24:58,760 --> 00:25:01,920 Each tries to stab and inseminate the other 209 00:25:01,920 --> 00:25:04,120 without being stabbed first. 210 00:25:14,200 --> 00:25:17,600 A strike anywhere on the body will fertilise. 211 00:25:50,520 --> 00:25:56,560 A successful strike and sperm is injected into the rival. 212 00:25:58,480 --> 00:26:00,040 The duel is over. 213 00:26:00,040 --> 00:26:05,360 The impregnated flatworm is left with the scar and the labour 214 00:26:05,360 --> 00:26:06,720 of laying the eggs. 215 00:26:15,160 --> 00:26:18,880 Its only solace - it's young will carry the genes 216 00:26:18,880 --> 00:26:20,440 of a master swordsman. 217 00:26:28,800 --> 00:26:33,040 Coral reefs are more than just hothouses for trying new versions 218 00:26:33,040 --> 00:26:34,480 of the mating game. 219 00:26:34,480 --> 00:26:39,120 They're also excellent places for meeting others of your own kind. 220 00:26:41,520 --> 00:26:43,480 The mantas are back. 221 00:26:43,480 --> 00:26:46,280 They're well fed and preparing to breed. 222 00:26:48,400 --> 00:26:51,080 These giant fish do not produce spawn. 223 00:26:53,080 --> 00:26:55,440 They breed in a more complex way. 224 00:26:58,480 --> 00:27:03,480 A fish is more likely to meet others of its own kind here, than wandering 225 00:27:03,480 --> 00:27:05,240 around in the open ocean. 226 00:27:08,480 --> 00:27:12,880 And while they wait for someone interesting to turn up, cleaner fish 227 00:27:12,880 --> 00:27:17,600 give them a going over, removing any parasites or bits of dead skin. 228 00:27:23,640 --> 00:27:25,200 They're quite choosy. 229 00:27:25,200 --> 00:27:28,600 Only a partner with the right abilities will do. 230 00:27:32,720 --> 00:27:36,400 Young mantas - not yet mature - flirt with the others. 231 00:27:42,240 --> 00:27:44,640 The adults mate belly to belly. 232 00:27:46,040 --> 00:27:50,840 Getting into the right position requires practice and coordination. 233 00:27:57,880 --> 00:28:01,200 They don't necessarily get it right first time. 234 00:28:17,640 --> 00:28:21,200 An adult female arrives and she is seeking a mate. 235 00:28:27,560 --> 00:28:31,080 Any interested male must now get down to business. 236 00:28:39,560 --> 00:28:41,200 Rehearsal time is over. 237 00:28:46,640 --> 00:28:49,360 Several males fancy their chances. 238 00:28:59,280 --> 00:29:02,800 She starts to twist and turn, while they follow. 239 00:29:13,000 --> 00:29:15,280 She's assessing their stamina. 240 00:29:20,080 --> 00:29:23,040 The courting males imitate her every move. 241 00:29:31,320 --> 00:29:35,440 This performance may go on for hours. 242 00:29:35,440 --> 00:29:38,000 Some males eventually start to tire. 243 00:29:41,840 --> 00:29:44,560 And now, she ups the tempo. 244 00:30:15,560 --> 00:30:19,160 Once she's made her choice, she slows down... 245 00:30:25,520 --> 00:30:27,840 ..and they mate. 246 00:30:31,240 --> 00:30:35,480 The genes that gave them both such speed and agility are now 247 00:30:35,480 --> 00:30:37,520 passed to the next generation. 248 00:30:41,560 --> 00:30:45,160 After mating, the male mantas play no further role 249 00:30:45,160 --> 00:30:46,880 in caring for their young. 250 00:30:48,120 --> 00:30:51,920 It's a strategy common to many ocean creatures. 251 00:30:53,240 --> 00:30:54,640 But not all. 252 00:30:59,720 --> 00:31:02,760 The coastal lagoons of Portugal. 253 00:31:08,800 --> 00:31:13,000 Here live fish that form long-term partnerships. 254 00:31:16,760 --> 00:31:18,400 The seahorse. 255 00:31:24,360 --> 00:31:28,200 This is a female, and she's looking for a partner. 256 00:31:32,040 --> 00:31:34,120 The choice is an important one, 257 00:31:34,120 --> 00:31:37,720 for the partnership is likely to last for years. 258 00:31:43,400 --> 00:31:45,200 Could he be the one? 259 00:32:04,520 --> 00:32:06,400 He's turned pale - 260 00:32:06,400 --> 00:32:08,760 a sign that he's interested. 261 00:32:14,680 --> 00:32:17,360 But she needs time to get to know him. 262 00:32:27,880 --> 00:32:29,880 Once she's certain, 263 00:32:29,880 --> 00:32:33,560 she, too, changes her colour to match his. 264 00:32:41,080 --> 00:32:45,080 Over the next few days, they barely leave each other's side, 265 00:32:45,080 --> 00:32:47,960 imitating one another's every move. 266 00:32:56,600 --> 00:33:01,080 Their synchronised swimming skills will determine the success 267 00:33:01,080 --> 00:33:04,600 or failure of the next stage in their partnership. 268 00:33:16,200 --> 00:33:20,800 Her belly is now swollen with eggs ready to be fertilised. 269 00:33:28,040 --> 00:33:31,520 On his belly, he has a pouch. 270 00:33:35,840 --> 00:33:39,360 For, in seahorse partnerships, 271 00:33:39,360 --> 00:33:43,080 parental responsibilities have been exchanged. 272 00:33:45,680 --> 00:33:49,360 So, now she's going to pass her precious eggs to him. 273 00:34:04,600 --> 00:34:08,320 The crucial act, the transfer, 274 00:34:08,320 --> 00:34:09,800 is about to happen. 275 00:34:13,960 --> 00:34:18,840 They position themselves with great precision, 276 00:34:18,840 --> 00:34:23,920 and she transfers all her eggs without losing a single one. 277 00:34:36,640 --> 00:34:41,560 The pouch on his belly now contains about 300 eggs. 278 00:34:44,400 --> 00:34:47,560 It's now up to him to look after them. 279 00:34:52,920 --> 00:34:57,680 And she is free to start producing the next batch of eggs. 280 00:35:12,920 --> 00:35:15,000 Three weeks later, 281 00:35:15,000 --> 00:35:18,520 and his pregnancy is almost at an end. 282 00:35:21,400 --> 00:35:27,400 His body starts contractions that slowly increase in intensity. 283 00:35:38,240 --> 00:35:40,280 And then... 284 00:35:42,760 --> 00:35:44,960 ..release. 285 00:35:55,680 --> 00:35:58,800 Many fish give birth to live young, 286 00:35:58,800 --> 00:36:04,160 but seahorses are the only group in which it is the males who do so. 287 00:36:08,560 --> 00:36:11,440 The young are just ten millimetres long, 288 00:36:11,440 --> 00:36:15,440 fully formed and ready to make their own way in life. 289 00:36:19,840 --> 00:36:23,240 Each a perfect miniature of its parents. 290 00:36:37,960 --> 00:36:44,040 This male's pregnancy has given him a guarantee of their paternity. 291 00:36:44,040 --> 00:36:46,360 And, by producing live young, 292 00:36:46,360 --> 00:36:49,760 he has given them an excellent chance of survival. 293 00:36:59,440 --> 00:37:02,760 Nowhere is the mating game more hectic than 294 00:37:02,760 --> 00:37:05,440 at the margins of the sea, 295 00:37:05,440 --> 00:37:08,080 where water disappears twice a day... 296 00:37:09,880 --> 00:37:12,600 ..and reveals mud. 297 00:37:19,680 --> 00:37:24,200 Here in the mangroves, fiddler crabs start the action just 298 00:37:24,200 --> 00:37:26,640 as soon as the water disappears. 299 00:37:33,200 --> 00:37:34,920 There's no time to lose. 300 00:37:37,640 --> 00:37:42,280 A male - his burrow could make an excellent family home. 301 00:37:45,120 --> 00:37:48,800 All he has to do is find a willing female. 302 00:37:54,240 --> 00:37:58,040 And he must do so before the water returns. 303 00:38:05,640 --> 00:38:11,040 His large yellow claw weighs as much as all the rest of his body, 304 00:38:11,040 --> 00:38:13,760 and is completely useless for feeding. 305 00:38:16,240 --> 00:38:19,560 But its colour does catch a female's eye. 306 00:38:21,520 --> 00:38:25,200 And, if she needs more convincing, 307 00:38:25,200 --> 00:38:27,280 the wave should do the trick. 308 00:38:35,360 --> 00:38:38,040 The tide turns, the clock is ticking. 309 00:38:46,240 --> 00:38:47,960 He needs to up his game. 310 00:38:51,160 --> 00:38:53,120 She seems distracted. 311 00:39:02,400 --> 00:39:04,920 Competition has arrived. 312 00:39:06,920 --> 00:39:08,560 Lots of it. 313 00:39:15,200 --> 00:39:18,920 All with the same desire. 314 00:39:18,920 --> 00:39:21,520 And all with moves just like his. 315 00:39:24,920 --> 00:39:26,720 Every time he waves... 316 00:39:32,120 --> 00:39:35,080 ..so do all his rivals. 317 00:39:39,040 --> 00:39:41,280 She is spoilt for choice. 318 00:39:58,160 --> 00:40:00,600 His time has almost run out. 319 00:40:14,120 --> 00:40:17,160 At last, she makes her choice. 320 00:40:19,200 --> 00:40:21,320 But it's not in his favour. 321 00:40:27,080 --> 00:40:30,200 He'll have to wait until the next tide, 322 00:40:30,200 --> 00:40:32,040 and then, try again. 323 00:40:44,760 --> 00:40:48,920 Many ocean animals only play the mating game once a year. 324 00:40:48,920 --> 00:40:52,760 So, for them, the stakes are particularly high. 325 00:40:56,680 --> 00:41:00,640 To win, a player must be prepared to risk everything. 326 00:41:03,080 --> 00:41:07,680 A colony of South American sea lions in Argentina. 327 00:41:09,280 --> 00:41:13,760 Every summer, for a few weeks, they gather on the shore. 328 00:41:19,200 --> 00:41:23,480 Heavily-pregnant females close to giving birth arrive 329 00:41:23,480 --> 00:41:25,480 in search of a place to do so. 330 00:41:29,040 --> 00:41:30,040 Any. 331 00:41:33,000 --> 00:41:35,720 These safe places give the mothers 332 00:41:35,720 --> 00:41:38,640 time to bond with their newborn young. 333 00:41:48,640 --> 00:41:52,800 But such prime real estate does not come rent-free. 334 00:41:56,120 --> 00:41:58,000 A beach master. 335 00:42:00,400 --> 00:42:03,200 Over 300 kilos of muscle. 336 00:42:10,680 --> 00:42:13,840 The females have landed on the territory that he had to 337 00:42:13,840 --> 00:42:15,640 fight hard to establish. 338 00:42:19,880 --> 00:42:23,080 Now, a week after giving birth, 339 00:42:23,080 --> 00:42:24,880 they're ready to mate again. 340 00:42:29,720 --> 00:42:33,920 And he aims to be the one to father their next pups. 341 00:42:36,680 --> 00:42:39,760 The trouble is, he's surrounded by other males. 342 00:42:44,200 --> 00:42:47,360 They all want females - and, just like him, 343 00:42:47,360 --> 00:42:50,080 they all fought to establish a territory. 344 00:42:56,160 --> 00:42:57,160 And. 345 00:43:07,720 --> 00:43:10,560 Squabbles are common... 346 00:43:10,560 --> 00:43:13,680 ..but, as long as each male stays in his own patch, 347 00:43:13,680 --> 00:43:16,640 they won't come to blows. 348 00:43:16,640 --> 00:43:21,320 But a crowd of fertile females inevitably attracts attention. 349 00:43:28,800 --> 00:43:31,840 A younger, smaller bachelor is on the lookout 350 00:43:31,840 --> 00:43:33,880 for just such an opportunity. 351 00:43:45,360 --> 00:43:49,680 On his own, he's no match for a battle hardened beach master. 352 00:43:55,080 --> 00:43:56,760 But he's not on his own. 353 00:43:58,920 --> 00:44:01,000 Other bachelors are watching. 354 00:44:07,560 --> 00:44:11,440 Each would like to steal a female from the beach master. 355 00:44:25,040 --> 00:44:28,280 But none of them wants to make the first move. 356 00:44:30,480 --> 00:44:32,760 SEAL BARKS 357 00:44:38,840 --> 00:44:42,520 Edging closer, they test the beach master's defences. 358 00:44:44,600 --> 00:44:46,040 One breaks ranks... 359 00:44:48,880 --> 00:44:51,200 ..and then they all invade his territory. 360 00:44:55,760 --> 00:45:01,000 As he tries to retain his panicking females and fight the intruders, 361 00:45:01,000 --> 00:45:03,760 the raid spills over into neighbouring territories. 362 00:45:08,440 --> 00:45:10,840 GROWLING AND BARKING 363 00:45:24,880 --> 00:45:27,200 GROWLING AND BARKING CONTINUES 364 00:45:40,640 --> 00:45:43,200 Now, the bachelors get their chance. 365 00:45:48,760 --> 00:45:53,000 Using others as cover, a bachelor grabs an unguarded female. 366 00:45:54,640 --> 00:45:58,360 Another targets one of the beach master's partners. 367 00:46:05,800 --> 00:46:07,600 He charges to her rescue. 368 00:46:10,560 --> 00:46:15,160 One on one, the beach master has the strength to stop any kidnap. 369 00:46:21,560 --> 00:46:24,800 The raid is short lived, but the beach master 370 00:46:24,800 --> 00:46:29,280 will have to face many more before the breeding season is over. 371 00:46:31,160 --> 00:46:35,320 Each battle will sap his strength and so shorten his reign. 372 00:46:39,560 --> 00:46:42,760 But bachelors who fail are even worse off. 373 00:46:45,800 --> 00:46:49,560 Only those with the size and strength to defend the territory 374 00:46:49,560 --> 00:46:53,240 and the females within it will win this mating game. 375 00:47:00,920 --> 00:47:07,120 His dominance may last for only a few years, but during that time 376 00:47:07,120 --> 00:47:09,280 he will father dozens of pups. 377 00:47:11,400 --> 00:47:14,280 Among them, the next generation of males. 378 00:47:20,160 --> 00:47:25,080 Including those with the genes that gave him the strength to become 379 00:47:25,080 --> 00:47:26,160 a beach master. 380 00:47:40,600 --> 00:47:44,680 For all those who play this mating game 381 00:47:44,680 --> 00:47:47,920 there is only one measure of success. 382 00:47:55,520 --> 00:48:01,520 A healthy newborn whale calf is living proof that both his father 383 00:48:01,520 --> 00:48:04,200 and mother had game plans that worked. 384 00:48:10,360 --> 00:48:13,880 Many aspects of those strategies remain a mystery. 385 00:48:18,760 --> 00:48:20,840 One thing, however, is clear. 386 00:48:22,320 --> 00:48:27,840 The success of any species anywhere depends on the skill 387 00:48:27,840 --> 00:48:31,720 with which its members manage to play the mating game. 388 00:48:40,920 --> 00:48:43,240 WHALE CALLS 389 00:48:45,760 --> 00:48:47,880 CALLING CONTINUES 390 00:48:51,560 --> 00:48:54,880 The humpback singers are just amazing. 391 00:48:58,200 --> 00:49:02,640 Just being next to one whale underwater is incredible, 392 00:49:02,640 --> 00:49:05,800 but then add the sound of those things. 393 00:49:05,800 --> 00:49:08,240 WHALE CALLS 394 00:49:13,040 --> 00:49:17,800 It just inhabits every pore of your body, every nerve cell 395 00:49:17,800 --> 00:49:19,760 in your brain. You just... 396 00:49:19,760 --> 00:49:22,800 Everything feels like sensory overload. 397 00:49:26,080 --> 00:49:31,720 There's just a weirdly difficult to describe feeling associated 398 00:49:31,720 --> 00:49:34,840 with being so close to something that's, you know, 399 00:49:34,840 --> 00:49:37,240 500 times your own weight. 400 00:49:39,360 --> 00:49:45,720 It's an incredibly exhilarating, demanding, exciting place to be. 401 00:49:53,240 --> 00:49:57,040 Filming a singing whale was the first of many challenges 402 00:49:57,040 --> 00:49:59,720 the mating game crew had ahead of them. 403 00:50:01,000 --> 00:50:04,840 Cinematographer Doug Anderson and team are attempting to film 404 00:50:04,840 --> 00:50:08,800 the spectacular mating contest of humpback whales. 405 00:50:08,800 --> 00:50:11,400 It's known as a heat run. 406 00:50:11,400 --> 00:50:13,960 100%, yeah. All right, you're good to go in the water. 407 00:50:13,960 --> 00:50:18,040 No-one really knows what happens on these courtship chases, 408 00:50:18,040 --> 00:50:20,400 and the crew hope to be the first people ever 409 00:50:20,400 --> 00:50:23,280 to document humpbacks mating. 410 00:50:23,280 --> 00:50:27,160 This thing is such an overt, massive piece of behaviour. 411 00:50:27,160 --> 00:50:28,280 What the detail? 412 00:50:28,280 --> 00:50:29,520 What's the details of this? 413 00:50:29,520 --> 00:50:33,040 What other behaviours are happening in there? Is there mating? 414 00:50:33,040 --> 00:50:36,360 Can we follow this chase to its conclusion? 415 00:50:37,720 --> 00:50:39,680 That was the bit that's exciting. 416 00:50:39,680 --> 00:50:41,880 From a photographer's point of view, 417 00:50:41,880 --> 00:50:45,320 we're going there with a bunch of new kit to just find out 418 00:50:45,320 --> 00:50:47,800 what happens and to do that 419 00:50:47,800 --> 00:50:50,000 we had to make a fancy pole cam. 420 00:50:52,440 --> 00:50:56,960 Doug's fancy pole cam is a stabilised camera fixed to the side 421 00:50:56,960 --> 00:50:57,960 of the boat. 422 00:50:59,040 --> 00:51:00,480 Do you want to just run on that? 423 00:51:01,680 --> 00:51:05,080 The plan is to position the boat alongside the whales 424 00:51:05,080 --> 00:51:09,840 during their courtship chase and use the camera to try and understand 425 00:51:09,840 --> 00:51:11,720 what the whales are doing. 426 00:51:17,440 --> 00:51:20,600 The team is working with experienced scientists 427 00:51:20,600 --> 00:51:25,360 who want to use this technology to learn more about whale behaviour. 428 00:51:27,000 --> 00:51:32,080 We had to get close and even though they are massive animals, 429 00:51:32,080 --> 00:51:35,520 they have an incredible ability just to swerve and miss 430 00:51:35,520 --> 00:51:36,800 and create space. 431 00:51:38,040 --> 00:51:40,000 And we became a part of it. 432 00:51:41,080 --> 00:51:42,280 Whales coming in at 12 o'clock. 433 00:51:43,320 --> 00:51:44,320 All right. 434 00:51:45,720 --> 00:51:48,920 Well, this is against... 435 00:51:48,920 --> 00:51:52,040 OK, let's get ready to go around to the right. 436 00:51:52,040 --> 00:51:53,400 Three, two, one, go. 437 00:51:53,400 --> 00:51:54,400 Go, go, go. 438 00:51:59,240 --> 00:52:01,520 Got it. OK. 439 00:52:01,520 --> 00:52:05,200 They just went underneath the bow. Going right or left? 440 00:52:05,200 --> 00:52:07,200 What speed are we going? 441 00:52:07,200 --> 00:52:09,840 The noise of the whales hitting each other on the surface, 442 00:52:09,840 --> 00:52:12,280 it's like, it's palpable. 443 00:52:12,280 --> 00:52:17,440 The crunching of these bodies coming together, it's visceral and violent. 444 00:52:22,400 --> 00:52:28,160 You could see individual whales and their strategies and whales 445 00:52:28,160 --> 00:52:30,520 bottling out and peeling away. 446 00:52:32,800 --> 00:52:34,680 On the left. 447 00:52:41,480 --> 00:52:47,680 It just felt like such a privileged view being allowed to be closer 448 00:52:47,680 --> 00:52:51,840 and in a more intimate position with this massive event 449 00:52:51,840 --> 00:52:53,840 than any film-maker ever has. 450 00:52:59,440 --> 00:53:04,320 It was incredible to see these extended shots of whales 451 00:53:04,320 --> 00:53:09,400 bashing into each other, competing for space and everything else. 452 00:53:09,400 --> 00:53:12,760 But we weren't seeing anything new. 453 00:53:12,760 --> 00:53:16,280 The pole cam provided an unparalleled view of one 454 00:53:16,280 --> 00:53:19,560 of the greatest battles in nature. 455 00:53:19,560 --> 00:53:23,120 But it didn't get the team any closer to revealing 456 00:53:23,120 --> 00:53:24,560 how a heat run ends. 457 00:53:27,000 --> 00:53:28,920 After following the chase for hours, 458 00:53:28,920 --> 00:53:33,200 the whales come to a halt and Doug takes the chance to get in the water 459 00:53:33,200 --> 00:53:35,280 right where the whales have stopped. 460 00:53:35,280 --> 00:53:37,760 We'll just try and get down on the edge of it. 461 00:53:37,760 --> 00:53:39,480 Like, to whatever depth it is. 462 00:53:41,520 --> 00:53:44,320 What he then witnessed was truly remarkable. 463 00:53:46,280 --> 00:53:52,080 We got in and she was just there hanging in the water. 464 00:53:57,800 --> 00:54:02,160 I think what was going through my head was, "If not now, 465 00:54:02,160 --> 00:54:07,840 "then when will I regret not just trying to become a part 466 00:54:07,840 --> 00:54:08,840 "of this scene?" 467 00:54:10,840 --> 00:54:15,720 I mean, adrenaline was high and excitement was through the roof. 468 00:54:17,640 --> 00:54:21,720 These animals are so large, and I had never even heard 469 00:54:21,720 --> 00:54:23,360 of anything like this. 470 00:54:23,360 --> 00:54:26,600 WHALES CALLING 471 00:54:30,800 --> 00:54:36,320 In the moment, I felt like I had an invitation to become 472 00:54:36,320 --> 00:54:39,400 as much a part of the scene as I could. 473 00:54:47,160 --> 00:54:49,840 I thought this is mating. 474 00:54:49,840 --> 00:54:51,840 He's won. 475 00:54:51,840 --> 00:54:55,120 I'm as close to mating as anyone has ever got. 476 00:55:00,160 --> 00:55:05,720 And the male came over her back and drew his chin so delicately 477 00:55:05,720 --> 00:55:10,200 over her back, almost like a caress across the top of her head. 478 00:55:11,920 --> 00:55:16,400 It was just such a tender moment between such enormous animals. 479 00:55:26,600 --> 00:55:29,160 The male beat his tail towards me. 480 00:55:29,160 --> 00:55:31,920 I didn't even find myself flinching. 481 00:55:31,920 --> 00:55:35,040 It was just a part of the moving of. 482 00:55:35,040 --> 00:55:36,960 And I was left bewildered. 483 00:55:38,320 --> 00:55:43,640 I thought I was going to see something that was an end to this. 484 00:55:43,640 --> 00:55:49,920 But actually all I saw was another bit, another chink through a window 485 00:55:49,920 --> 00:55:52,520 into what the heat run is. 486 00:55:54,760 --> 00:55:57,920 We have to go now, but... Because it's going to be dark. 487 00:55:59,320 --> 00:56:03,680 But I'm guessing that I don't know, that's it, that's the point. 488 00:56:03,680 --> 00:56:06,600 If I could have stayed there that night, 489 00:56:06,600 --> 00:56:13,560 and filmed in the dark, you know, or under moonlight or, you know, 490 00:56:13,560 --> 00:56:17,680 if we had the ability to do that, then it's in that space that we find 491 00:56:17,680 --> 00:56:24,240 the next piece of the puzzle of what this is for all 492 00:56:24,240 --> 00:56:29,360 of its bluster is the prequel to the main event. 493 00:56:33,240 --> 00:56:39,120 And we have just picked up the first tiny piece in the puzzle 494 00:56:39,120 --> 00:56:41,160 of what that is. 495 00:56:41,160 --> 00:56:42,440 And that is great. 496 00:56:43,760 --> 00:56:46,520 But I would love to see the rest of it. 497 00:56:48,600 --> 00:56:50,240 WHALES CALLING 498 00:56:58,000 --> 00:56:59,560 Next time... 499 00:56:59,560 --> 00:57:02,720 When animals that live in rainforests want to mate, 500 00:57:02,720 --> 00:57:07,040 their challenge is finding a way to stand out from the crowd. 501 00:57:09,000 --> 00:57:12,240 Some are spectacular show-offs. 502 00:57:12,240 --> 00:57:13,520 Others must fight. 503 00:57:15,400 --> 00:57:21,320 But sometimes working together is the key to success in jungles.