1 00:00:02,400 --> 00:00:06,760 Cast adrift in the far reaches of the Southern Hemisphere 2 00:00:06,760 --> 00:00:09,800 lies a continent separated from all other lands... 3 00:00:12,240 --> 00:00:14,400 ..for 45 million years. 4 00:00:19,000 --> 00:00:21,240 Evolving in isolation, 5 00:00:21,240 --> 00:00:23,920 nature has created a unique world of wonders. 6 00:00:31,920 --> 00:00:33,160 Spiders that dance... 7 00:00:35,120 --> 00:00:36,680 ..birds that spread fire... 8 00:00:39,040 --> 00:00:41,200 ..where bouncing beats walking 9 00:00:41,200 --> 00:00:43,720 and youngsters are carried in pouches. 10 00:00:45,960 --> 00:00:48,520 It's a world where animals have had to adapt 11 00:00:48,520 --> 00:00:50,840 to surprising diverse landscapes... 12 00:00:52,240 --> 00:00:54,040 ..and thrive in its vibrant seas... 13 00:01:00,800 --> 00:01:05,600 ..even making their homes amongst the growing concrete jungle. 14 00:01:09,480 --> 00:01:10,840 In this episode, 15 00:01:10,840 --> 00:01:13,920 travelling the currents that circle the continent, 16 00:01:13,920 --> 00:01:17,840 we discover what makes Australia's coastline so special... 17 00:01:21,520 --> 00:01:24,560 ..and why sea creatures from the world over 18 00:01:24,560 --> 00:01:27,400 are drawn to Earth's Magical Kingdom. 19 00:01:34,520 --> 00:01:37,640 Australia's ocean wilderness is one of the most extraordinary places 20 00:01:37,640 --> 00:01:39,880 on Earth. 21 00:01:42,640 --> 00:01:47,280 It spans three oceans and more than 4 million square miles. 22 00:01:49,520 --> 00:01:51,160 But that wasn't always the case. 23 00:01:53,680 --> 00:01:58,680 At one time, Australia was almost double its current size, 24 00:01:58,680 --> 00:02:01,400 until the seas rose to divide the land. 25 00:02:10,560 --> 00:02:15,640 The mountains that remain became Australia's 8,000 offshore islands. 26 00:02:20,600 --> 00:02:23,360 Often remote and uninhabited, 27 00:02:23,360 --> 00:02:28,040 today they provide space for rare animals to congregate and breed. 28 00:02:30,120 --> 00:02:34,960 40 miles off the coast of South Australia lies Pearson Island. 29 00:02:38,280 --> 00:02:41,520 It's the perfect place for an Australian sea lion 30 00:02:41,520 --> 00:02:42,760 to raise a pup. 31 00:02:49,440 --> 00:02:52,360 Not so long ago, the Australian sea lion 32 00:02:52,360 --> 00:02:55,120 was one of the rarest of its kind in the world. 33 00:02:56,160 --> 00:02:58,160 But they are thriving here. 34 00:03:01,600 --> 00:03:04,720 Protected from hunting, this colony has become 35 00:03:04,720 --> 00:03:07,000 one of the healthiest in Australia. 36 00:03:16,880 --> 00:03:20,120 Currents from the Southern Ocean bring cold, 37 00:03:20,120 --> 00:03:23,800 nutrient-rich upwellings, helping to create 38 00:03:23,800 --> 00:03:28,280 one of the world's least polluted and best stocked waterways. 39 00:03:36,920 --> 00:03:41,160 Ideal fishing grounds for a sea lion mum. 40 00:03:51,160 --> 00:03:55,240 The island's small, sandy bay is the perfect nursery for her pup. 41 00:04:03,400 --> 00:04:07,480 At four months, he's not confident enough to follow his mother 42 00:04:07,480 --> 00:04:09,240 into the waves just yet. 43 00:04:10,520 --> 00:04:14,560 So, he waits alone and watches more experienced youngsters 44 00:04:14,560 --> 00:04:16,360 play in the shallows. 45 00:04:21,000 --> 00:04:25,520 Perhaps someone closer to his own age will provide some company. 46 00:04:27,240 --> 00:04:29,360 But mothers can be protective... 47 00:04:36,080 --> 00:04:38,360 ..and fathers downright hostile. 48 00:04:56,040 --> 00:05:00,240 Mothers come ashore and reunite with their pups for a feed. 49 00:05:02,880 --> 00:05:04,760 But his wait continues. 50 00:05:17,320 --> 00:05:22,240 Finally, in what might be described as the toddler pool, 51 00:05:22,240 --> 00:05:25,800 he finds a playmate, from a different species, 52 00:05:25,800 --> 00:05:27,680 a long-nosed seal pup. 53 00:05:33,800 --> 00:05:37,240 Sheltered rock pools provide the perfect playground 54 00:05:37,240 --> 00:05:39,240 for youngsters of both species. 55 00:05:47,160 --> 00:05:51,080 Play is only a short-term distraction when you're hungry. 56 00:05:56,760 --> 00:05:59,200 But his wait will soon be over. 57 00:06:04,680 --> 00:06:09,280 Sea lions are some of nature's greatest ocean acrobats. 58 00:06:09,280 --> 00:06:12,040 So, simply coming ashore should be easy. 59 00:06:15,640 --> 00:06:20,920 Pearson Island is characterised by large, flat slabs of rock 60 00:06:20,920 --> 00:06:23,840 lying just below the water's surface. 61 00:06:33,160 --> 00:06:36,200 A successful landing calls for good timing. 62 00:06:57,240 --> 00:06:59,600 When the surf is this strong, 63 00:06:59,600 --> 00:07:02,920 it's more prudent to opt to the sandy beach. 64 00:07:07,560 --> 00:07:08,760 A feed at last. 65 00:07:14,760 --> 00:07:18,400 She will suckle her pup for 18 months 66 00:07:18,400 --> 00:07:22,040 until he gains his independence and can hunt alone 67 00:07:22,040 --> 00:07:24,160 in these abundant waters. 68 00:07:36,560 --> 00:07:38,720 But, for some island residents, 69 00:07:38,720 --> 00:07:41,400 there's no leaving this rocky outpost. 70 00:07:44,000 --> 00:07:50,000 When rising seas created this archipelago 10,000 years ago, 71 00:07:50,000 --> 00:07:52,960 some of its inhabitants were marooned, 72 00:07:52,960 --> 00:07:55,400 stranded since the last Ice Age 73 00:07:55,400 --> 00:07:58,400 on what was once an ancient mountain top. 74 00:08:00,440 --> 00:08:03,280 Including a particular type of wallaby. 75 00:08:07,000 --> 00:08:09,800 Now a unique subspecies, 76 00:08:09,800 --> 00:08:16,080 the Pearson Island black-footed rock wallaby ekes out an existence 77 00:08:16,080 --> 00:08:20,160 among the cracks and crevices of this harsh, rocky environment. 78 00:08:23,320 --> 00:08:28,040 With a population of 300 and no water source on this island, 79 00:08:28,040 --> 00:08:30,800 every drop is worth squabbling over. 80 00:08:40,200 --> 00:08:43,880 Their fluffy coats can become matted into dreadlocks 81 00:08:43,880 --> 00:08:45,320 like true castaways. 82 00:08:49,520 --> 00:08:53,840 Unlike the sea lions, these wallabies are stuck here for good. 83 00:08:55,560 --> 00:08:58,240 In the ocean, animals have the freedom 84 00:08:58,240 --> 00:09:01,200 to move and disperse over vast distances. 85 00:09:01,200 --> 00:09:03,320 Sometimes they travel alone. 86 00:09:03,320 --> 00:09:06,240 At other times they form great gatherings. 87 00:09:08,120 --> 00:09:13,600 In the wide shallows of Spencer Gulf on Australia's south coast, 88 00:09:13,600 --> 00:09:17,320 June is the time for an unusual midwinter gathering. 89 00:09:22,880 --> 00:09:26,560 This garden of seaweeds and sponges 90 00:09:26,560 --> 00:09:29,800 hosts a spectacle unique to these waters. 91 00:09:33,880 --> 00:09:38,160 Giant cuttlefish, a relative of the octopus, 92 00:09:38,160 --> 00:09:43,360 grow up to a metre long, making them the largest of their kind. 93 00:09:45,240 --> 00:09:47,120 They are only found in Australia. 94 00:09:50,000 --> 00:09:52,160 Masters of disguise, 95 00:09:52,160 --> 00:09:55,400 they change the colour and texture of their skin 96 00:09:55,400 --> 00:09:58,000 to blend with their surroundings. 97 00:10:03,760 --> 00:10:05,800 At this time of year, though, 98 00:10:05,800 --> 00:10:08,840 it's all about standing out from the crowd. 99 00:10:12,520 --> 00:10:17,960 This small patch of reef, less than half a square mile in size, 100 00:10:17,960 --> 00:10:21,200 has been inundated with thousands of courting cuttles. 101 00:10:25,880 --> 00:10:29,960 But, with a ratio of 11 males to every female, 102 00:10:29,960 --> 00:10:33,200 not every male is going to get lucky. 103 00:10:37,120 --> 00:10:41,720 This female has accepted the protection of a large alpha male. 104 00:10:47,680 --> 00:10:51,440 But now he must hold on to his mating rights 105 00:10:51,440 --> 00:10:55,960 in the face of constant challenges from persistent rivals. 106 00:11:03,880 --> 00:11:07,640 By splaying out his tentacles, turning white, 107 00:11:07,640 --> 00:11:09,760 angling his body at 45 degrees, 108 00:11:09,760 --> 00:11:13,040 he attempts to appear larger than his challenger. 109 00:11:17,160 --> 00:11:19,520 The female is hidden below, 110 00:11:19,520 --> 00:11:23,360 while waves of black add to his display of strength. 111 00:11:30,240 --> 00:11:34,680 As rivals converge on either side, the alpha male is distracted... 112 00:11:37,760 --> 00:11:40,040 ..and his mate drifts from cover. 113 00:11:45,920 --> 00:11:49,360 A smaller male sees an opportunity and moves in. 114 00:11:52,640 --> 00:11:55,680 The interloper drags her as far as he can 115 00:11:55,680 --> 00:11:58,480 before forcing her into his twisted embrace. 116 00:12:02,600 --> 00:12:06,520 But the larger alpha male is quick to reclaim his prize. 117 00:12:13,760 --> 00:12:17,040 He will flush out the sperm of his competitors 118 00:12:17,040 --> 00:12:20,040 to ensure only he fertilizes her eggs. 119 00:12:29,960 --> 00:12:31,800 Given a moment's respite, 120 00:12:31,800 --> 00:12:36,080 the pair can get down to the business of finding a place to nest. 121 00:12:40,760 --> 00:12:45,000 Any prospective home for the eggs requires close inspection. 122 00:12:48,840 --> 00:12:52,120 Satisfied, she deposits their first clutch. 123 00:13:02,320 --> 00:13:06,240 Now, with a prime nest site and a mate to guard, 124 00:13:06,240 --> 00:13:09,400 the male must continue to fend off rivals. 125 00:13:11,960 --> 00:13:16,120 Nest sites like these are coveted across the reef, 126 00:13:16,120 --> 00:13:19,800 and males are tireless in their efforts to claim them. 127 00:13:24,080 --> 00:13:26,600 This one is already taken. 128 00:13:26,600 --> 00:13:28,920 It's being guarded by a monster. 129 00:13:30,320 --> 00:13:33,200 One of the largest males on the reef. 130 00:13:33,200 --> 00:13:37,240 His dazzling white skin and flattened tentacles 131 00:13:37,240 --> 00:13:39,880 proclaim his strength and size. 132 00:13:42,600 --> 00:13:45,880 Other males, hoping to mate with his female under the rocks, 133 00:13:45,880 --> 00:13:47,840 move in. 134 00:14:06,440 --> 00:14:08,760 They cautiously test his resolve. 135 00:14:28,800 --> 00:14:31,240 The urge to mate emboldens them. 136 00:14:39,440 --> 00:14:42,000 The monster allows them even closer. 137 00:14:47,760 --> 00:14:51,920 Cuttlefish expel ink to confuse predators. 138 00:14:51,920 --> 00:14:55,000 But this is a desperate attempt to escape the clutches 139 00:14:55,000 --> 00:14:56,400 of one of their own. 140 00:15:01,400 --> 00:15:04,400 For now, the monster has secured his legacy. 141 00:15:07,960 --> 00:15:11,200 This marine spectacle was nearly lost forever. 142 00:15:12,920 --> 00:15:19,320 In a single season, fishermen caught 250 tonnes of cuttlefish 143 00:15:19,320 --> 00:15:24,240 at this breeding site before it was protected in 1998. 144 00:15:29,960 --> 00:15:33,760 Today, this annual gathering continues in peace 145 00:15:33,760 --> 00:15:35,640 in these inshore shallows. 146 00:15:42,160 --> 00:15:47,040 Stretching between Antarctica and Australia's outer fringes 147 00:15:47,040 --> 00:15:50,160 is the Southern Ocean, wild and remote. 148 00:15:52,400 --> 00:15:57,320 Far out at sea, polar winds from Antarctica whip up huge swells. 149 00:16:00,480 --> 00:16:03,280 This is the ocean's engine room, 150 00:16:03,280 --> 00:16:06,520 generating waves that roll across the planet. 151 00:16:09,160 --> 00:16:13,760 Australia's southern coastline is shaped by this powerful force. 152 00:16:22,400 --> 00:16:26,440 As the ocean swells near Australia's outer edge, 153 00:16:26,440 --> 00:16:29,160 waves build to a monumental size. 154 00:16:31,920 --> 00:16:34,920 Monsters ten meters high are not uncommon. 155 00:16:46,360 --> 00:16:50,360 In winter, when the sea is at its most savage, 156 00:16:50,360 --> 00:16:54,880 many ocean wanderers leave this violent seascape. 157 00:16:54,880 --> 00:16:58,760 They head north and seek refuge in the calmer waters 158 00:16:58,760 --> 00:17:00,960 of the Great Australian Bight. 159 00:17:08,360 --> 00:17:12,280 The Nullarbor Plain comes to a dramatic end 160 00:17:12,280 --> 00:17:17,600 with vertical cliffs plummeting to the ocean 120 metres below. 161 00:17:23,440 --> 00:17:28,000 Every winter, these cliffside coves provide refuge 162 00:17:28,000 --> 00:17:29,880 to southern right whales. 163 00:17:31,200 --> 00:17:33,680 Nearly 18 meters long, 164 00:17:33,680 --> 00:17:37,600 they are amongst the largest animals ever to have lived. 165 00:17:38,960 --> 00:17:43,040 This female left her feeding ground in the Antarctic 166 00:17:43,040 --> 00:17:45,640 and travelled over 2,000 miles to give birth. 167 00:17:52,160 --> 00:17:55,440 The warmer water is gentle on her newborn, 168 00:17:55,440 --> 00:17:58,640 which has yet to develop its insulating blubber. 169 00:18:07,960 --> 00:18:10,840 She will nurse her calf here for the next three months 170 00:18:10,840 --> 00:18:14,640 until it's strong enough to face the long migration south 171 00:18:14,640 --> 00:18:16,320 at the start of spring. 172 00:18:19,160 --> 00:18:23,440 But these coves don't just provide nursery waters. 173 00:18:23,440 --> 00:18:26,880 They are the arena for spectacular mating events. 174 00:18:28,320 --> 00:18:30,520 This female is without a calf. 175 00:18:36,360 --> 00:18:38,080 Four males close in on her. 176 00:18:46,800 --> 00:18:51,440 A group of bottlenose dolphins become curious onlookers. 177 00:18:56,400 --> 00:19:00,160 To ensure only the most well-endowed succeed, 178 00:19:00,160 --> 00:19:02,160 the female goes belly up. 179 00:19:05,720 --> 00:19:10,400 The penis of a southern right whale extends to almost four metres. 180 00:19:12,680 --> 00:19:15,240 Several males will mate with her 181 00:19:15,240 --> 00:19:18,440 but only the last will father her offspring. 182 00:19:31,800 --> 00:19:35,160 Unlike the whales, this pod of dolphins 183 00:19:35,160 --> 00:19:38,120 will remain by the coast throughout the year. 184 00:19:40,800 --> 00:19:44,080 Despite the size difference, the dolphins are happy 185 00:19:44,080 --> 00:19:47,280 to share their home with the visiting giants. 186 00:19:48,520 --> 00:19:52,560 The whale even appears to mimic its more agile playmates. 187 00:19:56,880 --> 00:20:02,800 Renowned for being easy to approach, right whales were named by whalers 188 00:20:02,800 --> 00:20:05,520 who consider them the right whale to hunt... 189 00:20:11,120 --> 00:20:15,360 ..their curious and playful nature making them easy targets. 190 00:20:22,480 --> 00:20:26,760 But play is not limited to whales and dolphins. 191 00:20:26,760 --> 00:20:30,400 Every winter, surfers take to the water. 192 00:20:30,400 --> 00:20:34,080 It's a time when waves are often at their best 193 00:20:34,080 --> 00:20:36,360 thanks to the Southern Ocean swell. 194 00:20:41,520 --> 00:20:45,040 The dolphins seem to take pleasure in joining them. 195 00:21:04,600 --> 00:21:08,160 Research has shown that these synchronised displays 196 00:21:08,160 --> 00:21:11,000 help male dolphins form alliances. 197 00:21:25,680 --> 00:21:30,040 Wild dolphins enjoy the lighter side of life on the southern coast. 198 00:21:30,040 --> 00:21:35,200 1000 miles east, there are far darker goings-on. 199 00:21:40,680 --> 00:21:43,920 Port Phillip Bay is on the doorstep of Melbourne, 200 00:21:43,920 --> 00:21:46,120 Australia's second largest city. 201 00:21:47,600 --> 00:21:51,840 But few residents have witnessed the marine spectacle 202 00:21:51,840 --> 00:21:55,280 that unfolds in these shallows every winter. 203 00:21:58,360 --> 00:22:04,120 At nearly half a metre in width, Australian giant spider crabs 204 00:22:04,120 --> 00:22:07,440 are amongst the world's largest crustaceans. 205 00:22:09,720 --> 00:22:11,360 Seldom seen, 206 00:22:11,360 --> 00:22:14,600 they spend the years scavenging on the seabed. 207 00:22:17,680 --> 00:22:22,080 But this crab has got a feeling that it's time for a change. 208 00:22:28,200 --> 00:22:30,240 It is soon joined by others. 209 00:22:32,480 --> 00:22:36,120 Normally dwelling in depths of up to 800 meters, 210 00:22:36,120 --> 00:22:39,720 these crabs migrate to the shallows each winter. 211 00:22:42,800 --> 00:22:47,480 Not to mate, but to moult - to shed their old shells. 212 00:22:51,320 --> 00:22:55,000 It's believed that an influx of cold water from the Southern Ocean 213 00:22:55,000 --> 00:22:57,160 triggers this mass migration. 214 00:23:12,720 --> 00:23:16,840 Before long, the ocean floor is a writhing carpet 215 00:23:16,840 --> 00:23:21,280 of claws and spindly legs, sometimes several creatures thick. 216 00:23:25,680 --> 00:23:28,320 In the world above, normality rules. 217 00:23:29,920 --> 00:23:31,560 Life continues as usual. 218 00:23:54,080 --> 00:23:58,800 Scratching at its face is a sign that this crab's change has begun. 219 00:24:02,480 --> 00:24:07,200 Like all crustaceans, its body is protected by a hard exoskeleton. 220 00:24:09,600 --> 00:24:14,360 But, in order to grow, the crab must remove its old shell 221 00:24:14,360 --> 00:24:16,280 and reveal a new one beneath. 222 00:24:22,200 --> 00:24:27,640 Its new orange shell, though larger, is flexible and able to bend 223 00:24:27,640 --> 00:24:29,840 as the crab works its way out. 224 00:24:33,120 --> 00:24:37,160 But this temporary softness will prove to be its downfall. 225 00:24:39,840 --> 00:24:44,520 It's one of the first to expose its new, soft shell, 226 00:24:44,520 --> 00:24:48,600 and its hard-bodied neighbours waste no time 227 00:24:48,600 --> 00:24:50,960 in seizing an opportunity for a meal. 228 00:24:57,560 --> 00:25:02,360 When growing a new shell, crabs need as much protein as they can get, 229 00:25:02,360 --> 00:25:04,840 no matter how macabre the source. 230 00:25:20,280 --> 00:25:22,920 Once a limb is plucked from the victim, 231 00:25:22,920 --> 00:25:25,960 the attacker quickly retreats with its prize. 232 00:25:45,880 --> 00:25:49,680 Despite the perils of moulting in the midst of cannibals, 233 00:25:49,680 --> 00:25:54,080 these crabs in a tree gathered together for safety in numbers. 234 00:25:57,240 --> 00:26:00,080 There is a greater threat to their kind. 235 00:26:06,160 --> 00:26:11,000 Smooth stingrays, armed with venom-tipped tails, 236 00:26:11,000 --> 00:26:13,280 have stalked the crabs to the shallows. 237 00:26:18,120 --> 00:26:19,880 At over two metres wide, 238 00:26:19,880 --> 00:26:23,040 these are the largest stingrays in the world. 239 00:26:30,920 --> 00:26:34,960 Defenceless crustaceans are sucked from their soft shells. 240 00:26:39,160 --> 00:26:41,680 With this many moulting at once, 241 00:26:41,680 --> 00:26:45,040 even the most insatiable ray can't eat them all. 242 00:26:55,840 --> 00:26:58,840 The carnage continues well into the night. 243 00:27:20,120 --> 00:27:23,960 It takes around three weeks for all the crabs to moult 244 00:27:23,960 --> 00:27:29,000 and then, just as suddenly as they came, they're gone, 245 00:27:29,000 --> 00:27:31,520 disappearing back into the deep 246 00:27:31,520 --> 00:27:34,720 where their lives largely remain a mystery. 247 00:27:39,600 --> 00:27:43,880 A few leftovers from the feast of rays are all that remain. 248 00:27:56,280 --> 00:27:59,760 One reason for Australia's many marine marvels 249 00:27:59,760 --> 00:28:04,360 is that while the Southern Ocean chills the south, 250 00:28:04,360 --> 00:28:07,200 two more oceans bring warm, tropical water from the north. 251 00:28:09,920 --> 00:28:13,760 In the west, it's the Indian Ocean. In the east, the mighty Pacific. 252 00:28:17,400 --> 00:28:21,800 On this side of the country, the land dives beneath the waves 253 00:28:21,800 --> 00:28:24,080 and stretches far out to sea. 254 00:28:25,160 --> 00:28:28,560 This shallow continental shelf shapes life here. 255 00:28:31,400 --> 00:28:34,120 It forms gentle, sloping beaches. 256 00:28:36,360 --> 00:28:39,000 And islands mark where it breaks the surface. 257 00:28:43,800 --> 00:28:48,680 100 miles up the coast from Sydney sits a rather special one. 258 00:28:54,600 --> 00:28:59,640 Cabbage Tree Island is the only island in the entire region 259 00:28:59,640 --> 00:29:02,240 that remains covered in rain forest. 260 00:29:09,840 --> 00:29:13,200 The palms that give it its name have also given rise 261 00:29:13,200 --> 00:29:15,240 to an extraordinary sea bird. 262 00:29:19,240 --> 00:29:21,600 Beneath the forest canopy, 263 00:29:21,600 --> 00:29:25,600 the rocky slopes are littered with nooks and crannies 264 00:29:25,600 --> 00:29:28,040 and, at the right time of year, 265 00:29:28,040 --> 00:29:33,160 a little ball of fluff can invariably be found inside each one. 266 00:29:34,480 --> 00:29:37,600 It is one of only two breeding colonies 267 00:29:37,600 --> 00:29:41,480 of Gould's petrel in the world. 268 00:29:43,160 --> 00:29:46,960 This chick is around three weeks old. 269 00:29:46,960 --> 00:29:50,360 It's been left alone to fend for itself 270 00:29:50,360 --> 00:29:52,440 while its parents are fishing at sea. 271 00:30:07,960 --> 00:30:13,400 The spider poses no real threat but best not to take your chances 272 00:30:13,400 --> 00:30:16,200 when its legspan is wider than you are. 273 00:30:22,120 --> 00:30:25,600 By nightfall, there is still no sign of mum or dad. 274 00:30:30,760 --> 00:30:31,880 But then... 275 00:30:35,800 --> 00:30:41,240 A somewhat undignified entrance but then landing takes practice 276 00:30:41,240 --> 00:30:44,680 and it's a skill seldom used by petrels. 277 00:30:48,280 --> 00:30:53,000 This species spends years out at sea without touching dry land. 278 00:30:53,000 --> 00:30:57,200 So, walking over a rocky forest floor is an alien sensation. 279 00:31:07,320 --> 00:31:11,240 To make matters trickier, almost every hole under a rock... 280 00:31:13,280 --> 00:31:14,920 ..has a chick in it. 281 00:31:18,000 --> 00:31:22,040 It is believed that adults use a keen sense of smell 282 00:31:22,040 --> 00:31:25,400 to find their way back to their nest hole. 283 00:31:25,400 --> 00:31:29,520 But it doesn't appear to be a fail-safe method. 284 00:31:29,520 --> 00:31:30,960 Wrong hole. 285 00:31:39,120 --> 00:31:44,240 Finally, after some searching, mum and chick are reunited, 286 00:31:44,240 --> 00:31:47,600 and chick gets a meal of regurgitated squid. 287 00:31:50,920 --> 00:31:53,920 Over the next 12 weeks, night after night, 288 00:31:53,920 --> 00:31:56,840 crash landing after crash landing, 289 00:31:56,840 --> 00:32:01,200 chicks all over this tiny island will wait for parents to return. 290 00:32:02,880 --> 00:32:06,600 Until the one night when they won't come back. 291 00:32:22,160 --> 00:32:28,480 Four months later, with only a tiny crown of fluffy down left, 292 00:32:28,480 --> 00:32:31,880 the petrel chick has been abandoned by its parents. 293 00:32:35,800 --> 00:32:39,640 It's been two weeks since it's had anything at all to eat. 294 00:32:41,040 --> 00:32:43,960 The bird knows something must be done. 295 00:32:43,960 --> 00:32:49,000 But hunger, desperation and instinct need to sufficiently combine 296 00:32:49,000 --> 00:32:51,960 before it has the will to make its move. 297 00:32:54,080 --> 00:32:58,120 For those who don't, the island holds no future. 298 00:33:08,200 --> 00:33:11,640 Like his parents, it's under the cover of darkness 299 00:33:11,640 --> 00:33:14,120 that the young bird leaves the nest. 300 00:33:21,240 --> 00:33:25,000 Sea birds like petrels rely on the wind 301 00:33:25,000 --> 00:33:27,880 to give them the lift needed for takeoff. 302 00:33:29,200 --> 00:33:33,440 But, down here, beneath the forest canopy, the air is listless. 303 00:33:37,080 --> 00:33:40,680 An ill-judged attempt at flight could be his last. 304 00:33:43,640 --> 00:33:48,440 Sharp palms and jagged rocks don't make for good crash mats. 305 00:33:50,720 --> 00:33:53,840 To stand any chance of getting off the island, 306 00:33:53,840 --> 00:33:57,360 it must get out from under the canopy. 307 00:33:57,360 --> 00:33:59,720 But trees cover the whole island. 308 00:34:11,840 --> 00:34:13,960 There's only one thing for it. 309 00:34:25,480 --> 00:34:29,200 Webbed feet and wings are not ideal equipment 310 00:34:29,200 --> 00:34:32,560 for a sheer vertical climb of eight meters. 311 00:34:34,000 --> 00:34:38,400 But the petrels have evolved sharp claws and a hooked beak 312 00:34:38,400 --> 00:34:40,080 to aid their ascent. 313 00:34:47,000 --> 00:34:51,040 As the saying goes, if at first you don't succeed. 314 00:34:58,960 --> 00:35:03,000 Attempting to climb again pushes the starving fledgling 315 00:35:03,000 --> 00:35:04,880 closer to exhaustion. 316 00:35:05,880 --> 00:35:10,400 But frantic wing flapping helps to propel the bird up the tree. 317 00:35:12,560 --> 00:35:15,760 The fledgling wraps its wings around the trunk 318 00:35:15,760 --> 00:35:19,440 for a moment's respite, using its tail feathers as a prop. 319 00:35:37,160 --> 00:35:40,960 Having made it to the top, more obstacles lie in wait. 320 00:35:53,000 --> 00:35:55,920 The thick stems at the centre of the palm fronds 321 00:35:55,920 --> 00:35:57,600 are lined with the sharp spikes. 322 00:35:59,880 --> 00:36:02,000 Feathers are easily entangled. 323 00:36:11,080 --> 00:36:15,720 Part fall, part flight, either way, it's airborne! 324 00:36:18,720 --> 00:36:23,240 It won't touch land again for five or six years. 325 00:36:25,640 --> 00:36:30,400 As the Gould's petrels head off for a life far out at sea, 326 00:36:30,400 --> 00:36:33,240 other ocean wanderers are being drawn 327 00:36:33,240 --> 00:36:35,640 to Australia's Pacific coastline. 328 00:36:42,960 --> 00:36:47,840 Once a year, humpback whales pass Cabbage Tree Island 329 00:36:47,840 --> 00:36:49,600 on their journey north. 330 00:36:54,000 --> 00:36:58,160 They have come to give birth to their young in the warm shallows. 331 00:37:19,160 --> 00:37:23,640 One occasional visitor is the subject of myth and legend. 332 00:37:28,040 --> 00:37:31,560 Migaloo. The albino humpback whale. 333 00:37:41,920 --> 00:37:45,520 His name means white fella in Aboriginal language. 334 00:37:58,360 --> 00:38:02,960 His pale colour is most likely due to a rare genetic mutation. 335 00:38:08,720 --> 00:38:14,800 Believed to be 32 years old, Migaloo is in his prime, 336 00:38:14,800 --> 00:38:17,440 and he knows how to demonstrate his power. 337 00:38:27,120 --> 00:38:31,920 Scientists believe tail slapping and rolling 338 00:38:31,920 --> 00:38:34,200 is a form of communication between whales. 339 00:38:44,960 --> 00:38:48,120 First sighted in 1991, 340 00:38:48,120 --> 00:38:52,040 Migaloo was thought to be the only white whale in existence. 341 00:38:55,040 --> 00:38:58,640 Since then, white calves have been spotted in the Pacific 342 00:38:58,640 --> 00:39:00,920 around New Zealand and Australia. 343 00:39:00,920 --> 00:39:05,960 It's thought Migaloo may be the father of these pale youngsters. 344 00:39:08,640 --> 00:39:14,520 Migaloo travels up Australia's east coast, or Humpback Highway, 345 00:39:14,520 --> 00:39:15,960 as he heads each year 346 00:39:15,960 --> 00:39:19,880 for one of the country's most precious natural wonders. 347 00:39:23,520 --> 00:39:28,080 The Great Barrier Reef spans 130 square miles 348 00:39:28,080 --> 00:39:30,760 of Queensland's Pacific coast. 349 00:39:36,440 --> 00:39:41,960 This enormous coral kingdom covers roughly the same area as Germany. 350 00:39:44,400 --> 00:39:47,840 It's warm shallow waters and deserted islands 351 00:39:47,840 --> 00:39:50,680 are not only home to colourful characters, 352 00:39:50,680 --> 00:39:54,520 they also provide a pit stop for ocean voyagers 353 00:39:54,520 --> 00:39:59,160 and ancient mariners such as the green sea turtle. 354 00:40:09,120 --> 00:40:11,800 After years of life in the open ocean, 355 00:40:11,800 --> 00:40:15,440 this expectant mother has come back to lay her eggs 356 00:40:15,440 --> 00:40:18,680 in the very same place where her life began... 357 00:40:21,120 --> 00:40:22,600 ..Raine Island. 358 00:40:31,520 --> 00:40:35,560 With flippers designed for sea and not sand, 359 00:40:35,560 --> 00:40:39,600 hauling her enormous body up onto the shore 360 00:40:39,600 --> 00:40:41,800 takes an extraordinary effort. 361 00:40:52,840 --> 00:40:56,720 She carefully carves out a nest in the sand, 362 00:40:56,720 --> 00:40:59,480 her one and only act of parental care. 363 00:41:07,200 --> 00:41:11,120 And deposits a clutch of around 100 eggs. 364 00:41:14,160 --> 00:41:18,400 As she returned to the waves, more mothers clamber up the beach. 365 00:41:18,400 --> 00:41:20,800 In fact, many, many more. 366 00:41:23,000 --> 00:41:27,040 14,000 turtles can come ashore here in a single night. 367 00:41:51,000 --> 00:41:56,000 After laying, the females return to the waters around Raine Island 368 00:41:56,000 --> 00:42:00,320 for a couple of weeks before returning to lay another clutch. 369 00:42:11,040 --> 00:42:14,600 Two months later, the sand begins to stir. 370 00:42:30,040 --> 00:42:32,920 Hatchlings begin their race to the water. 371 00:42:38,480 --> 00:42:42,840 But by night, ghost crabs haunt this beach. 372 00:43:03,400 --> 00:43:05,440 Another crab lies in ambush. 373 00:43:12,160 --> 00:43:13,360 But ghost crabs... 374 00:43:15,640 --> 00:43:18,680 ..are not the greatest threat that they will face. 375 00:43:22,960 --> 00:43:26,400 In the open ocean, more predators await. 376 00:43:26,400 --> 00:43:31,360 It's estimated that just one in a thousand hatchlings survive. 377 00:43:35,120 --> 00:43:39,360 The young turtles will travel on Australia's ocean currents. 378 00:43:42,600 --> 00:43:46,080 Some will be carried east, into the South Pacific. 379 00:43:47,720 --> 00:43:50,560 Others will be swept north, towards Asia. 380 00:43:54,480 --> 00:43:59,120 The separation of the land between Asia and Australia 381 00:43:59,120 --> 00:44:01,440 creates a passageway for tropical water. 382 00:44:02,800 --> 00:44:07,040 Australia is the only continent with warm currents flowing south 383 00:44:07,040 --> 00:44:08,480 on two sides. 384 00:44:12,640 --> 00:44:15,720 Without this, the Indian Ocean off Western Australia 385 00:44:15,720 --> 00:44:17,160 would be far colder... 386 00:44:21,440 --> 00:44:24,680 ..instead of the tropical environment that it is. 387 00:44:28,200 --> 00:44:32,600 On this remote coastline, humans are few and far between. 388 00:44:34,480 --> 00:44:39,320 It's an example of what marine ecosystems should look like. 389 00:44:39,320 --> 00:44:42,960 Healthy, interconnected and teeming with life. 390 00:44:45,200 --> 00:44:49,240 100 miles off the coast lie the Lacepede Islands. 391 00:44:54,560 --> 00:44:59,240 18,000 pairs of brown boobies nest here. 392 00:45:03,520 --> 00:45:07,560 It's breeding season and, on an exposed edge of the beach, 393 00:45:07,560 --> 00:45:10,600 a new couple are hoping to start a family. 394 00:45:14,480 --> 00:45:17,680 With a weedy offering, he attempts to woo her. 395 00:45:19,680 --> 00:45:20,840 Perhaps another try. 396 00:45:22,160 --> 00:45:23,520 No. 397 00:45:23,520 --> 00:45:25,920 Surely his efforts have been sufficient? 398 00:45:31,600 --> 00:45:32,800 Maybe not. 399 00:45:38,240 --> 00:45:42,440 Booby nests are often little more than a small pile of sticks. 400 00:45:43,720 --> 00:45:46,920 Some are barely an indentation in the pebbles. 401 00:45:49,440 --> 00:45:52,800 Parenting is approached in a variety of styles. 402 00:45:56,040 --> 00:45:57,720 Some respond to nagging. 403 00:46:04,200 --> 00:46:06,440 While others stand their ground. 404 00:46:15,200 --> 00:46:17,800 A beak skills lesson is taking place. 405 00:46:21,120 --> 00:46:25,520 Imitating parents helps chicks practice their catching skills. 406 00:46:30,640 --> 00:46:35,280 Becoming adept at flipping sticks and stones will prepare them 407 00:46:35,280 --> 00:46:37,920 to manipulate slippery fish mid-flight. 408 00:46:44,040 --> 00:46:48,720 As midday temperatures rise to around 40 degrees Celsius, 409 00:46:48,720 --> 00:46:52,560 parents hover like beach umbrellas over their chicks. 410 00:46:55,400 --> 00:46:58,440 Domestic duties are shared between parents. 411 00:47:00,080 --> 00:47:02,280 And this chick needs feeding. 412 00:47:07,760 --> 00:47:10,440 Out at sea, the boobies move en masse. 413 00:47:11,520 --> 00:47:15,640 They have spotted splashing in the distance. 414 00:47:15,640 --> 00:47:20,120 A school of tuna have driven a shoal of sardines to the surface. 415 00:47:27,480 --> 00:47:31,200 Fish are pushed up, straight into the boobies' waiting beaks. 416 00:47:35,200 --> 00:47:37,040 Frigate birds join the plunder. 417 00:47:46,840 --> 00:47:51,480 Having taken their fill, parents head home to their hungry chicks. 418 00:47:57,840 --> 00:48:01,600 Back at the island, other frigate birds are patrolling. 419 00:48:03,240 --> 00:48:06,800 They are known as the pirates of the skies, 420 00:48:06,800 --> 00:48:07,920 for good reason. 421 00:48:09,960 --> 00:48:13,000 Larger and faster than the boobies, 422 00:48:13,000 --> 00:48:17,000 they bully the smaller sea birds into giving up their lunch. 423 00:48:23,160 --> 00:48:28,040 Outmanoeuvred, it's forced to disgorge its food mid-air. 424 00:48:41,640 --> 00:48:46,200 Onshore, the tiny chick's wait for a meal should finally be over. 425 00:48:48,000 --> 00:48:51,360 The mates greet each other but lunch was stolen. 426 00:48:56,080 --> 00:49:00,200 Now the onus of providing a meal falls to the other parent. 427 00:49:07,360 --> 00:49:11,280 Fortunately, at this time of year, food is abundant. 428 00:49:15,480 --> 00:49:22,160 In winter, cycling ocean currents fuel huge blooms of plankton, 429 00:49:22,160 --> 00:49:25,960 providing a sudden bounty of food for small fish. 430 00:49:28,760 --> 00:49:30,800 Enormous schools of sardines form. 431 00:49:33,880 --> 00:49:36,560 And these, in turn, attract bigger fish. 432 00:49:38,080 --> 00:49:39,320 Dusky sharks. 433 00:49:41,320 --> 00:49:45,360 Fast, streamlined predators around three metres in length. 434 00:50:03,520 --> 00:50:08,040 Bigger sharks come to feast, too, including the biggest of them all. 435 00:50:08,040 --> 00:50:09,560 The whale shark. 436 00:50:11,840 --> 00:50:15,640 12 meters long and weighing as much as 11 tonnes. 437 00:50:21,200 --> 00:50:23,440 Despite their imposing size, 438 00:50:23,440 --> 00:50:27,200 they feed on the same microscopic plankton as the sardines. 439 00:50:33,160 --> 00:50:38,600 Chemicals released by the plankton are carried on the ocean currents. 440 00:50:38,600 --> 00:50:42,320 The whale sharks follow their sensitive noses 441 00:50:42,320 --> 00:50:45,960 to find these blooms in the waters of Ningaloo, 442 00:50:45,960 --> 00:50:49,240 a protected area of Australia's west coast. 443 00:50:54,840 --> 00:50:57,320 Scientists want to understand 444 00:50:57,320 --> 00:51:00,400 how the individuals here are related. 445 00:51:00,400 --> 00:51:04,640 They believe that they may be part of a whale shark family 446 00:51:04,640 --> 00:51:08,600 that spans both the Pacific and the Indian Oceans. 447 00:51:11,920 --> 00:51:16,160 To be sure, the scientist needs a sample of each whale's DNA. 448 00:51:22,000 --> 00:51:25,840 Remarkably, the giant animal will hang calmly 449 00:51:25,840 --> 00:51:27,800 while its nose is scratched. 450 00:51:30,240 --> 00:51:32,480 Completely relaxed, 451 00:51:32,480 --> 00:51:35,480 the shark seems to enter a trance-like state... 452 00:51:43,040 --> 00:51:47,720 ..allowing the scientists to scrape tiny parasites off its body. 453 00:51:50,640 --> 00:51:54,000 These parasites, known as copepods, 454 00:51:54,000 --> 00:51:57,800 chew the shark's skin and drink its blood. 455 00:51:57,800 --> 00:52:01,120 So, in return for the DNA sample, 456 00:52:01,120 --> 00:52:04,360 the whale shark gets rid of a few free loaders. 457 00:52:19,840 --> 00:52:23,560 Research has now shown that Australian whale sharks 458 00:52:23,560 --> 00:52:27,520 are the offspring of ocean-wandering parents from as far away 459 00:52:27,520 --> 00:52:29,640 as Indonesia and New Guinea. 460 00:52:32,800 --> 00:52:36,400 Here in Ningaloo, the giants have a precious sanctuary 461 00:52:36,400 --> 00:52:40,840 from hunters in a place where they are a protected species. 462 00:52:55,080 --> 00:52:59,160 Most sharks are cold blooded and are therefore restricted 463 00:52:59,160 --> 00:53:03,840 to warm waters, like those along Australia's remote western coast. 464 00:53:09,000 --> 00:53:14,640 Shark Bay, 500 miles north of Perth, can justly claim its ominous name. 465 00:53:15,680 --> 00:53:19,160 The water is bath-like for most of the year. 466 00:53:29,280 --> 00:53:32,160 Sharks have an acute sense of smell, 467 00:53:32,160 --> 00:53:38,040 capable of detecting the faintest traces of blood in the water. 468 00:53:38,040 --> 00:53:42,280 But an entire whale carcass is like a siren going off... 469 00:53:44,760 --> 00:53:47,120 ..alerting sharks for miles around. 470 00:53:48,720 --> 00:53:49,960 Tiger sharks. 471 00:53:51,920 --> 00:53:56,880 Threatened globally, here they can still be found in numbers. 472 00:54:06,600 --> 00:54:10,880 New arrivals skirt the dead whale before entering the fray. 473 00:54:17,440 --> 00:54:21,080 These predators have hunted the world's oceans 474 00:54:21,080 --> 00:54:25,760 for more than 50 million years and they're not above scavenging. 475 00:54:39,560 --> 00:54:42,800 The feeding frenzy has attracted sightseers. 476 00:54:45,880 --> 00:54:49,720 Despite a notorious reputation for attacks on people, 477 00:54:49,720 --> 00:54:54,000 tourists are keen to catch a glimpse of these striking animals. 478 00:55:13,040 --> 00:55:14,920 Attacks on people are very rare 479 00:55:14,920 --> 00:55:18,120 but sharks have been persecuted for centuries, 480 00:55:18,120 --> 00:55:23,080 and the government of Western Australia still employs hunters 481 00:55:23,080 --> 00:55:26,080 to kill these endangered animals. 482 00:55:28,320 --> 00:55:31,960 But, when a chance encounter like this enables people 483 00:55:31,960 --> 00:55:35,040 to get close to animals that they may fear, 484 00:55:35,040 --> 00:55:38,680 their enjoyment could trigger a change in attitude. 485 00:55:43,760 --> 00:55:47,880 Nowhere is that more important than here in Australia, 486 00:55:47,880 --> 00:55:51,840 where coasts are nourished by three oceans, 487 00:55:51,840 --> 00:55:54,920 creating a nexus for marine life. 488 00:56:00,360 --> 00:56:02,240 From the warm Indian Ocean, 489 00:56:02,240 --> 00:56:06,320 with its schools of awe-inspiring predators, 490 00:56:06,320 --> 00:56:08,760 to the calm shallows of the Pacific, 491 00:56:08,760 --> 00:56:12,000 with its reefs and islands, 492 00:56:12,000 --> 00:56:15,440 and the rich and varied southern seas 493 00:56:15,440 --> 00:56:20,720 with gatherings of species found nowhere else on Earth, 494 00:56:20,720 --> 00:56:26,760 the meeting of these three oceans has produced an explosion of life 495 00:56:26,760 --> 00:56:29,640 in Earth's Magical Kingdom.