1 00:00:02,680 --> 00:00:02,800 (SWEEPING ORCHESTRAL MUSIC) 2 00:00:42,120 --> 00:00:45,280 (DRAMATIC ORCHESTRAL MUSIC) 3 00:00:46,880 --> 00:00:49,600 NARRATOR: Of all the creatures in the deep blue sea, 4 00:00:49,640 --> 00:00:52,800 the one that never fails to strike fear in the heart 5 00:00:52,840 --> 00:00:56,040 is the great white shark, or white pointer. 6 00:00:56,080 --> 00:00:59,080 (DRAMATIC ORCHESTRAL MUSIC) 7 00:01:01,000 --> 00:01:03,840 Hollywood has made these animals infamous 8 00:01:03,880 --> 00:01:07,440 through fictional films such as 'Jaws' and 'Dark Tide'... 9 00:01:10,920 --> 00:01:12,320 ..but make no mistake, 10 00:01:12,360 --> 00:01:15,320 the premise behind these movies is real. 11 00:01:20,920 --> 00:01:23,760 Great white sharks are natural born killers, 12 00:01:23,800 --> 00:01:26,120 lurking in the coastal surface waters 13 00:01:26,160 --> 00:01:28,320 of all the major oceans on Earth. 14 00:01:32,080 --> 00:01:33,680 They prefer temperate waters, 15 00:01:33,720 --> 00:01:35,920 but are often sighted in the tropics. 16 00:01:35,960 --> 00:01:39,160 (DRAMATIC ORCHESTRAL MUSIC) 17 00:01:41,240 --> 00:01:43,800 Two locations that are well known for great whites 18 00:01:43,840 --> 00:01:45,160 are South Africa 19 00:01:45,200 --> 00:01:46,840 and the Great Australian Bight, 20 00:01:46,880 --> 00:01:48,960 off the coast of South Australia. 21 00:01:53,800 --> 00:01:55,520 (DRAMATIC MUSIC BUILDS) 22 00:01:55,560 --> 00:01:59,760 In both places, ocean currents carry water from Antarctica 23 00:01:59,800 --> 00:02:04,880 laden with tiny organisms that form the basis of a complex web of life. 24 00:02:07,200 --> 00:02:10,560 Plankton attracts fish, fish attract seals, 25 00:02:10,600 --> 00:02:13,240 seals attract the great white shark. 26 00:02:15,040 --> 00:02:18,560 And the great white sharks, well, they attract people. 27 00:02:20,040 --> 00:02:22,480 Cage diving with these charismatic creatures 28 00:02:22,520 --> 00:02:24,360 has become big business. 29 00:02:28,360 --> 00:02:30,160 During seal breeding season, 30 00:02:30,200 --> 00:02:33,560 the supply of shark food is almost unlimited. 31 00:02:35,240 --> 00:02:37,040 Despite their formidable appearance, 32 00:02:37,080 --> 00:02:40,760 great white sharks are not a huge threat to humans. 33 00:02:43,240 --> 00:02:47,600 It is true about 100 people a year are attacked by sharks, 34 00:02:47,640 --> 00:02:50,840 and probably about half of those are made by great whites... 35 00:02:54,520 --> 00:02:56,520 ..but most are not fatal. 36 00:02:58,640 --> 00:03:02,400 Zoologists now know that these animals are naturally curious, 37 00:03:02,440 --> 00:03:06,040 and most injuries to humans are just sample bites. 38 00:03:07,520 --> 00:03:10,160 Great white sharks prefer to prey on sealions, 39 00:03:10,200 --> 00:03:13,680 small-toothed whales, and sometimes other sharks. 40 00:03:18,200 --> 00:03:20,360 They really are the ultimate hunters. 41 00:03:20,400 --> 00:03:22,680 Shaped like torpedoes, 42 00:03:22,720 --> 00:03:26,040 they can tear through the water at 15 miles per hour. 43 00:03:30,600 --> 00:03:34,240 Fully grown great white sharks have around 300 teeth 44 00:03:34,280 --> 00:03:36,080 arranged in several rows. 45 00:03:36,120 --> 00:03:39,960 The ones at the front are knifelike, with serrated edges. 46 00:03:40,000 --> 00:03:42,800 Intimidating and effective. 47 00:03:47,200 --> 00:03:50,320 Fortunately, the cages used on dives such as this 48 00:03:50,360 --> 00:03:53,320 protect those who seek the thrill of a close encounter 49 00:03:53,360 --> 00:03:55,880 without any associated risk. 50 00:04:01,760 --> 00:04:05,400 The great white's sense of smell is no urban myth. 51 00:04:05,440 --> 00:04:09,240 They can detect and home in on a small amount of blood 52 00:04:09,280 --> 00:04:11,840 from as far as 5km away. 53 00:04:15,920 --> 00:04:20,080 Unlike most fish, these incredible sharks are warm-blooded, 54 00:04:20,120 --> 00:04:23,040 which is why they can maintain their body temperature 55 00:04:23,080 --> 00:04:25,480 in seas all over the world. 56 00:04:28,880 --> 00:04:30,880 (JAUNTY ORCHESTRAL MUSIC) 57 00:04:30,920 --> 00:04:35,240 Cage diving with great whites is the ultimate adrenalin rush, 58 00:04:35,280 --> 00:04:38,880 but the experience also allows scientists 59 00:04:38,920 --> 00:04:42,480 to increase their understanding of this remarkable species 60 00:04:42,520 --> 00:04:45,000 and its place on the blue planet. 61 00:04:46,520 --> 00:04:49,280 Aquariums, which are slowly becoming as popular as zoos 62 00:04:49,320 --> 00:04:51,080 throughout the world, 63 00:04:51,120 --> 00:04:56,160 also afford opportunity for us to learn more about life underwater... 64 00:04:57,360 --> 00:04:59,520 ..and to encounter less aggressive sharks 65 00:04:59,560 --> 00:05:03,000 in their admittedly somewhat controlled environment. 66 00:05:05,320 --> 00:05:08,080 The size of the tanks clearly restricts the size 67 00:05:08,120 --> 00:05:10,880 of the creatures that feature in such exhibits. 68 00:05:11,920 --> 00:05:14,760 So, if you want to encounter the biggest fish in the sea, 69 00:05:14,800 --> 00:05:17,200 you'll need to return to the wild. 70 00:05:22,562 --> 00:05:22,682 (HAUNTING INSTRUMENTAL MUSIC) 71 00:05:24,962 --> 00:05:28,202 NARRATOR: Despite their name, whale sharks are not whales, 72 00:05:28,242 --> 00:05:31,482 but it's obvious how the confusion has come about. 73 00:05:31,522 --> 00:05:35,922 They are enormous - 20 times larger than the great white. 74 00:05:38,642 --> 00:05:41,122 Fossils indicate this gargantuan fish 75 00:05:41,162 --> 00:05:45,002 may have been around for 250 million years. 76 00:05:45,042 --> 00:05:48,282 It's a true dinosaur of the seas, 77 00:05:48,322 --> 00:05:50,482 but humans need not be alarmed. 78 00:05:50,522 --> 00:05:54,322 The only prey on this giant's menu is microscopic. 79 00:05:56,642 --> 00:06:01,042 Encounters with whale sharks are awe-inspiring, to say the least, 80 00:06:01,082 --> 00:06:03,962 and one of the most reliable places to see them 81 00:06:04,002 --> 00:06:06,082 is here on Ningaloo Reef, 82 00:06:06,122 --> 00:06:08,242 off the coast of Western Australia. 83 00:06:11,722 --> 00:06:16,722 These gentle creatures swim to the surface to feed on tiny zoo plankton. 84 00:06:16,762 --> 00:06:19,482 So, it's easy to get relatively close to them 85 00:06:19,522 --> 00:06:21,442 just with a mask and snorkel. 86 00:06:24,042 --> 00:06:26,442 Whale sharks gulp enormous quantities of water 87 00:06:26,482 --> 00:06:28,322 into their wide mouths, 88 00:06:28,362 --> 00:06:32,522 then filter out the plankton through a kind of sieve in their throats. 89 00:06:34,442 --> 00:06:37,402 They do have teeth - 3,000 of them, in fact - 90 00:06:37,442 --> 00:06:42,002 but they are barely 6mm long and never used for eating. 91 00:06:44,602 --> 00:06:47,842 Humans discovered whale sharks relatively recently. 92 00:06:47,882 --> 00:06:51,842 The first recorded sighting was less than 200 years ago. 93 00:06:53,162 --> 00:06:55,522 To better understand their migratory behaviour, 94 00:06:55,562 --> 00:06:57,642 and in so doing, afford this species 95 00:06:57,682 --> 00:07:00,122 better protection from illegal fishing, 96 00:07:00,162 --> 00:07:03,162 scientists will occasionally fit an individual 97 00:07:03,202 --> 00:07:05,402 with a radio tracking device, 98 00:07:05,442 --> 00:07:10,042 a relatively harmless procedure that is akin to having your ears pierced. 99 00:07:13,602 --> 00:07:16,962 A less invasive tracking technique uses photo ID. 100 00:07:18,042 --> 00:07:21,042 So, anyone with an underwater camera can contribute 101 00:07:21,082 --> 00:07:25,322 simply by photographing the skin of any whale shark they encounter, 102 00:07:25,362 --> 00:07:29,282 for their spots are as unique as a human fingerprint. 103 00:07:33,962 --> 00:07:36,562 Through this citizen science project, 104 00:07:36,602 --> 00:07:39,442 whale shark specialists have been able to determine 105 00:07:39,482 --> 00:07:41,642 the migratory patterns of individuals 106 00:07:41,682 --> 00:07:44,162 and better monitor the global population. 107 00:07:53,402 --> 00:07:58,242 Whale sharks cruise through Ningaloo every year between April and August, 108 00:07:58,282 --> 00:08:01,882 and they don't appear to be bothered by humans at all. 109 00:08:04,562 --> 00:08:08,562 Ningaloo is one of the longest fringing coral reefs in the world. 110 00:08:08,602 --> 00:08:13,002 It's a beautiful wild place bathed in warm, clear water. 111 00:08:14,402 --> 00:08:16,802 The diversity of life here is bewildering. 112 00:08:20,842 --> 00:08:24,162 Ningaloo lies at the point where the southern temperate waters 113 00:08:24,202 --> 00:08:27,122 meet the northern tropical currents of the Indian Ocean. 114 00:08:29,962 --> 00:08:32,682 It's home to over 200 different corals 115 00:08:32,722 --> 00:08:35,362 and 500 species of fish. 116 00:08:44,882 --> 00:08:47,882 (GENTLE INSTRUMENTAL MUSIC) 117 00:08:49,922 --> 00:08:54,402 This pristine reef is a favourite hangout for another majestic giant, 118 00:08:54,442 --> 00:08:56,082 the manta ray. 119 00:08:57,442 --> 00:09:01,042 Like all rays, these graceful mantas are a type of shark. 120 00:09:04,202 --> 00:09:06,322 Growing to 5.5 metres wide, 121 00:09:06,362 --> 00:09:08,682 they are closely related to stingrays, 122 00:09:08,722 --> 00:09:12,122 but thankfully there's no nasty barb in their tails. 123 00:09:14,922 --> 00:09:17,922 They do have teeth, but they're shaped like pebbles, 124 00:09:17,962 --> 00:09:20,442 and not designed for biting prey. 125 00:09:24,522 --> 00:09:29,002 Manta rays spend most of their time swimming in large vertical loops, 126 00:09:29,042 --> 00:09:31,242 sucking in plankton as they go. 127 00:09:33,402 --> 00:09:36,402 (GENTLE INSTRUMENTAL MUSIC) 128 00:09:36,442 --> 00:09:39,362 Until recently, marine biologists believed 129 00:09:39,402 --> 00:09:42,402 mantas depended almost entirely on plankton. 130 00:09:45,122 --> 00:09:46,882 But research now reveals 131 00:09:46,922 --> 00:09:49,642 manta rays only get about a quarter of their nutrition 132 00:09:49,682 --> 00:09:51,682 from this kind of surface feeding. 133 00:09:51,722 --> 00:09:54,442 They catch the rest of it, mainly fish, 134 00:09:54,482 --> 00:09:57,042 hunting in the darker reaches of the ocean. 135 00:09:58,282 --> 00:10:02,762 Tagged rays have been recorded swimming to depths below 400 metres. 136 00:10:05,042 --> 00:10:07,642 And evidence is emerging that these impressive swimmers 137 00:10:07,682 --> 00:10:10,362 can dive down as far as a kilometre. 138 00:10:15,802 --> 00:10:18,602 Cephalic lobes on either side of their mouths 139 00:10:18,642 --> 00:10:21,242 are actually pectoral fins, 140 00:10:21,282 --> 00:10:23,682 adapted to help mantas funnel their food. 141 00:10:30,802 --> 00:10:34,642 (JAUNTY ORCHESTRAL MUSIC) 142 00:10:34,682 --> 00:10:36,682 Not all of the sea's creatures 143 00:10:36,722 --> 00:10:39,762 are famous for their propensity to kill or good looks. 144 00:10:39,802 --> 00:10:42,522 Some are incredible to encounter 145 00:10:42,562 --> 00:10:44,842 simply because they are so bizarre. 146 00:10:49,882 --> 00:10:51,482 Just off the coast of Whyalla, 147 00:10:51,522 --> 00:10:52,922 in South Australia, 148 00:10:52,962 --> 00:10:55,082 there's a 10km stretch of rock 149 00:10:55,122 --> 00:10:56,962 on the seabed 150 00:10:57,002 --> 00:10:59,002 that, well, isn't particularly remarkable 151 00:10:59,042 --> 00:11:02,122 unless you happen to be here in winter. 152 00:11:06,602 --> 00:11:09,682 This is the only time, and place in the world, for that matter, 153 00:11:09,722 --> 00:11:12,442 where you can reliably see huge numbers 154 00:11:12,482 --> 00:11:15,522 of giant Australian cuttlefish. 155 00:11:15,562 --> 00:11:18,842 (JAUNTY MUSIC CONTINUES) 156 00:11:23,242 --> 00:11:26,482 With bodies, or mantles, around 1.5 foot long, 157 00:11:26,522 --> 00:11:30,082 they are the largest of their kind in the world. 158 00:11:32,642 --> 00:11:35,602 Giant cuttlefish come here every winter to breed 159 00:11:35,642 --> 00:11:38,082 because the seabed is a perfect platform 160 00:11:38,122 --> 00:11:40,322 for females to anchor their eggs. 161 00:11:48,442 --> 00:11:52,642 In true rock star fashion, they live fast and die young, 162 00:11:52,682 --> 00:11:56,922 curling up their ten tentacles shortly after spawning. 163 00:11:56,962 --> 00:12:01,202 Young cuttlefish take 12 to 18 months to reach maturity. 164 00:12:01,242 --> 00:12:05,202 So, they are only sexually active for a single season. 165 00:12:06,922 --> 00:12:09,922 Their primary role is simply to live long enough 166 00:12:09,962 --> 00:12:12,682 to pass their flashy, overconfident genes 167 00:12:12,722 --> 00:12:14,282 to the next generation. 168 00:12:17,762 --> 00:12:20,002 The jack of all performing trades, 169 00:12:20,042 --> 00:12:22,482 cuttlefish have the underwater visual effects department 170 00:12:22,522 --> 00:12:24,002 well covered. 171 00:12:25,002 --> 00:12:27,082 They can change colour in an instant, 172 00:12:27,122 --> 00:12:30,922 and work their way through a kaleidoscopic range of patterns. 173 00:12:32,522 --> 00:12:35,242 They use these skills to help them with camouflage 174 00:12:35,282 --> 00:12:37,682 or to signal alarm, 175 00:12:37,722 --> 00:12:40,882 but during their mating ritual, it's all about showing off 176 00:12:40,922 --> 00:12:43,322 and upping your reproductive stakes. 177 00:12:47,202 --> 00:12:50,322 Cuttlefish have been around for hundreds of millions of years... 178 00:12:53,282 --> 00:12:54,682 ..which begs the question, 179 00:12:54,722 --> 00:12:57,962 who is the real alien in this underwater encounter? 180 00:13:00,202 --> 00:13:03,202 The strange new creatures who seek to enter this world 181 00:13:03,242 --> 00:13:05,802 or the cuttlefish they've come to admire? 182 00:13:09,558 --> 00:13:09,678 (TINKLING CHIME MUSIC) 183 00:13:15,518 --> 00:13:17,958 there's a collection of volcanic islands... 184 00:13:20,278 --> 00:13:23,358 ..that, in their geographic isolation, have developed habitats 185 00:13:23,398 --> 00:13:26,918 that have enabled many unique species to evolve. 186 00:13:35,558 --> 00:13:39,278 On land, they appear to have little to fear from humans. 187 00:13:39,318 --> 00:13:42,198 Indeed, the reverse appears to be true. 188 00:13:47,598 --> 00:13:50,678 These islands and their incredible collection of animals. 189 00:13:50,718 --> 00:13:53,558 inspired Charles Darwin to write a book 190 00:13:53,598 --> 00:13:57,038 that changed the way we think about life on Earth forever. 191 00:14:00,358 --> 00:14:02,438 They are, of course, the incomparable: 192 00:14:07,678 --> 00:14:10,438 There are 19 islands in the group in total, 193 00:14:10,478 --> 00:14:12,598 and they sit right on the equator. 194 00:14:12,638 --> 00:14:14,478 Their location is key 195 00:14:14,518 --> 00:14:17,318 to the strange and wonderful creatures that live here, 196 00:14:17,358 --> 00:14:19,398 particularly under the sea. 197 00:14:22,718 --> 00:14:25,278 The Galapagos lie in a kind of triangle 198 00:14:25,318 --> 00:14:28,638 created by the meeting of three great ocean currents. 199 00:14:28,678 --> 00:14:31,278 This has a dramatic effect on the weather, 200 00:14:31,318 --> 00:14:35,118 allowing a vast range of marine animals to wind up here. 201 00:14:43,078 --> 00:14:46,958 The famous marine iguana is unique to the Galapagos Islands. 202 00:14:49,198 --> 00:14:53,278 It's the only lizard that lives purely on algae and seaweed 203 00:14:53,318 --> 00:14:55,038 and swims underwater. 204 00:14:56,358 --> 00:14:58,518 They're almost certainly descendants 205 00:14:58,558 --> 00:15:01,278 of the forest-dwelling iguanas of South America. 206 00:15:03,398 --> 00:15:05,678 The theory is storms on the mainland 207 00:15:05,718 --> 00:15:08,598 may have set adrift rafts of sticks and debris, 208 00:15:08,638 --> 00:15:13,278 and a few unlucky land-based iguanas became stuck on board. 209 00:15:13,318 --> 00:15:15,958 They were carried by the ocean current 210 00:15:15,998 --> 00:15:18,678 and dumped here to begin a new life. 211 00:15:18,718 --> 00:15:21,238 Over countless generations, 212 00:15:21,278 --> 00:15:24,238 they evolved the ability to survive by the sea. 213 00:15:25,598 --> 00:15:27,438 Sharp teeth for scraping algae, 214 00:15:27,478 --> 00:15:29,678 a flattened tail for swimming, 215 00:15:29,718 --> 00:15:31,678 and even a special gland 216 00:15:31,718 --> 00:15:34,918 which removes excess salt from their bloodstream. 217 00:15:47,598 --> 00:15:50,438 Birds also rule the Galapagos roost... 218 00:15:51,518 --> 00:15:53,598 ..but two of the more striking seabirds 219 00:15:53,638 --> 00:15:57,678 are the frigate, with its extraordinary red throat pouch, 220 00:15:57,718 --> 00:15:59,758 and the blue-footed booby, 221 00:15:59,798 --> 00:16:03,358 easily identified by its outlandish blue feet. 222 00:16:04,638 --> 00:16:07,838 The males are very proud of their blue suede shoes, 223 00:16:07,878 --> 00:16:10,478 and show them off during mating dances. 224 00:16:10,518 --> 00:16:13,958 The guy with the bluest feet usually gets the girl, 225 00:16:13,998 --> 00:16:17,078 and the opportunity to pass on his genes. 226 00:16:23,958 --> 00:16:26,078 The Galapagos Islands are also home 227 00:16:26,118 --> 00:16:28,478 to the world's only equatorial penguin. 228 00:16:31,878 --> 00:16:33,878 They are a small but determined bird, 229 00:16:33,918 --> 00:16:38,878 ungainly on land, but absolutely amazing to witness underwater. 230 00:16:44,358 --> 00:16:47,678 (GENTLE INSTRUMENTAL MUSIC) 231 00:16:59,118 --> 00:17:01,598 One of the most joyous sights in the ocean 232 00:17:01,638 --> 00:17:04,878 can be found in almost all the warm waters of the world. 233 00:17:07,278 --> 00:17:08,718 Dolphins. 234 00:17:10,038 --> 00:17:11,838 At last count, 235 00:17:11,878 --> 00:17:15,318 scientists think we have 38 different species of marine dolphin, 236 00:17:15,358 --> 00:17:17,678 plus another five living in rivers. 237 00:17:23,558 --> 00:17:26,798 Australian has 14 different marine dolphin species, 238 00:17:26,838 --> 00:17:30,038 and some of them are almost too easy to meet. 239 00:17:33,758 --> 00:17:36,758 (UPLIFTING MUSIC SWELLS) 240 00:17:41,318 --> 00:17:43,278 Just offshore from the busy port city 241 00:17:43,318 --> 00:17:45,158 of Adelaide, in South Australia, 242 00:17:45,198 --> 00:17:47,158 dolphins will go out of their way 243 00:17:47,198 --> 00:17:49,518 to initiate close encounters with humans. 244 00:17:52,118 --> 00:17:55,118 The most common species here is the bottle-nosed dolphin. 245 00:17:55,158 --> 00:17:59,718 These sociable animals live in pods, groups of around 12 individuals 246 00:17:59,758 --> 00:18:02,558 that have developed a range of social skills 247 00:18:02,598 --> 00:18:05,398 to survive and support each other. 248 00:18:16,958 --> 00:18:18,758 Communication is key. 249 00:18:18,798 --> 00:18:22,758 Dolphins use a complex combination of squeaks and clicks 250 00:18:22,798 --> 00:18:24,198 to talk to each other. 251 00:18:26,478 --> 00:18:29,638 Their range of hearing is ten times greater than humans, 252 00:18:29,678 --> 00:18:33,838 so they can pick up high-pitched sounds that we are unable to hear. 253 00:18:35,838 --> 00:18:38,158 Dolphins usually hunt in a team, 254 00:18:38,198 --> 00:18:40,038 rounding up schools of fish, 255 00:18:40,078 --> 00:18:43,758 keeping them corralled until everyone has had an easy feed. 256 00:18:44,878 --> 00:18:47,758 Most dolphins in large pods are female 257 00:18:47,798 --> 00:18:49,838 and not related to one another, 258 00:18:49,878 --> 00:18:53,278 although mothers will stay with their young for up to eight years. 259 00:19:01,038 --> 00:19:04,078 (JAUNTY INSTRUMENTAL MUSIC) 260 00:19:04,118 --> 00:19:07,438 Male dolphins form smaller pods of two or three, 261 00:19:07,478 --> 00:19:10,038 and they are thought to become friends for life. 262 00:19:12,518 --> 00:19:15,358 They only approach the females when it's time to mate, 263 00:19:15,398 --> 00:19:17,118 which is often. 264 00:19:17,158 --> 00:19:20,398 Dolphins can actually mate at any time of the year. 265 00:19:20,438 --> 00:19:22,798 When a female gives birth, 266 00:19:22,838 --> 00:19:24,678 the others in her pod will help her, 267 00:19:24,718 --> 00:19:26,758 then go on to play a major role 268 00:19:26,798 --> 00:19:29,158 in protecting and rearing the offspring. 269 00:19:45,278 --> 00:19:47,998 Many marine parks and aquariums around the world 270 00:19:48,038 --> 00:19:50,998 offer opportunities to interact with dolphins. 271 00:19:56,758 --> 00:19:58,358 They vie for attention 272 00:19:58,398 --> 00:20:02,798 with other equally endearing marine animals such as the beluga whale. 273 00:20:02,838 --> 00:20:06,838 Calves are born grey, fading to white as they mature. 274 00:20:08,038 --> 00:20:11,358 Adults are easily distinguishable by their rounded foreheads 275 00:20:11,398 --> 00:20:13,398 and lack of dorsal fin. 276 00:20:15,718 --> 00:20:18,878 And they clearly enjoy an appreciative audience. 277 00:20:25,520 --> 00:20:29,440 NARRATOR: The Great Barrier Reef is a massive community of animals. 278 00:20:29,480 --> 00:20:33,920 It comprises over 3,000 individual reef systems. 279 00:20:35,920 --> 00:20:37,320 It runs along 280 00:20:37,360 --> 00:20:38,720 Australia's eastern coast, 281 00:20:38,760 --> 00:20:39,920 from the Tropic of Capricorn, 282 00:20:39,960 --> 00:20:41,880 north towards the equator. 283 00:20:50,360 --> 00:20:53,800 The incredible variety of life here is hard to take in. 284 00:20:53,840 --> 00:20:56,560 The world's largest collection of corals 285 00:20:56,600 --> 00:21:00,760 frequented by over 1,500 species of fish. 286 00:21:03,080 --> 00:21:06,520 It's difficult to comprehend that a structure so large, 287 00:21:06,560 --> 00:21:08,560 it's even visible from space, 288 00:21:08,600 --> 00:21:10,880 begins with a tiny coral polyp, 289 00:21:10,920 --> 00:21:14,960 a soft-bodied animal related to jellyfish and sea anemones. 290 00:21:20,400 --> 00:21:23,400 A young polyp begins life drifting in the ocean. 291 00:21:23,440 --> 00:21:25,240 When it lands in a suitable home, 292 00:21:25,280 --> 00:21:27,680 it attaches itself to the sea bed, 293 00:21:27,720 --> 00:21:30,920 somewhere warm and shallow with lots of sunshine. 294 00:21:33,720 --> 00:21:36,960 Then the miraculous process of reef-building begins. 295 00:21:43,320 --> 00:21:45,400 These families of coral polyps 296 00:21:45,440 --> 00:21:48,600 have created a wonder of magical shapes and colours 297 00:21:48,640 --> 00:21:50,360 over many thousands of years. 298 00:21:52,560 --> 00:21:55,880 And of course, they provide a perfect home for the countless creatures 299 00:21:55,920 --> 00:21:57,840 living in the tropical seas. 300 00:22:01,520 --> 00:22:04,120 The toxic stinging cells of the sea anemone 301 00:22:04,160 --> 00:22:06,360 are also an underwater oddity, 302 00:22:06,400 --> 00:22:09,560 for they provide protection for another small creature, 303 00:22:09,600 --> 00:22:12,160 the iconic clownfish. 304 00:22:12,200 --> 00:22:14,520 This little fish would be easy prey 305 00:22:14,560 --> 00:22:16,960 for the larger predators on the reef, 306 00:22:17,000 --> 00:22:19,720 so it's worked out a way to stay safe 307 00:22:19,760 --> 00:22:24,320 by living between the dangerous tentacles of a sea anemone. 308 00:22:24,360 --> 00:22:27,480 So, how does it avoid being stung and eaten 309 00:22:27,520 --> 00:22:30,880 like all the other fish unfortunate enough to swim this way? 310 00:22:30,920 --> 00:22:34,360 The answer is by being very careful. 311 00:22:35,360 --> 00:22:38,760 When a clownfish first arrives at a potential anemone home, 312 00:22:38,800 --> 00:22:40,800 it performs a kind of dance, 313 00:22:40,840 --> 00:22:43,560 gently touching the anemone's tentacles. 314 00:22:43,600 --> 00:22:47,120 This allows the fish to become accustomed to its stings. 315 00:22:47,160 --> 00:22:51,320 Clownfish also develop a thick mucous on their skin, 316 00:22:51,360 --> 00:22:53,360 which aids their protection. 317 00:22:55,200 --> 00:22:59,240 Their ability to live where other fish fear to venture is astounding, 318 00:22:59,280 --> 00:23:02,960 but so too is their ability to change sex. 319 00:23:04,080 --> 00:23:06,240 Clownfish are all born male. 320 00:23:06,280 --> 00:23:08,080 Once a group is established, 321 00:23:08,120 --> 00:23:11,840 the largest will miraculously turn into a female 322 00:23:11,880 --> 00:23:13,920 to ensure reproduction continues. 323 00:23:15,400 --> 00:23:17,400 As the dominant individual in the group, 324 00:23:17,440 --> 00:23:21,840 she becomes capable of laying eggs for the males to fertilise. 325 00:23:21,880 --> 00:23:23,880 If the female dies, 326 00:23:23,920 --> 00:23:28,000 then the largest remaining male will step up and change sex 327 00:23:28,040 --> 00:23:29,840 to take her place. 328 00:23:37,560 --> 00:23:41,960 The Great Barrier Reef really is like an enormous underwater city. 329 00:23:42,000 --> 00:23:45,280 It provides shelter, food, and company 330 00:23:45,320 --> 00:23:48,320 for whole communities of extraordinary animals, 331 00:23:48,360 --> 00:23:53,000 and one essential service that keeps the entire system healthy 332 00:23:53,040 --> 00:23:55,840 is provided at cleaning stations. 333 00:23:58,560 --> 00:24:02,120 These stations are set up by a handful of unusual creatures, 334 00:24:02,160 --> 00:24:04,760 such as the aptly named cleaner shrimp... 335 00:24:07,640 --> 00:24:11,600 ..who survive by cleaning and eating dead cells and parasites 336 00:24:11,640 --> 00:24:13,840 from the skin of larger animals. 337 00:24:18,080 --> 00:24:21,240 The local fish know where to go to get their teeth cleaned, 338 00:24:21,280 --> 00:24:23,600 and so do the local divers. 339 00:24:23,640 --> 00:24:26,640 (UPBEAT INSTRUMENTAL MUSIC) 340 00:24:30,360 --> 00:24:32,200 Cleaner shrimp are so confident, 341 00:24:32,240 --> 00:24:36,200 they will even crawl into the gill cavities and mouths of big fish 342 00:24:36,240 --> 00:24:38,640 without any fear of being eaten. 343 00:24:44,760 --> 00:24:46,960 Scientists have recently discovered 344 00:24:47,000 --> 00:24:49,680 how crucial cleaning stations are to the reef. 345 00:24:53,000 --> 00:24:55,480 In sample areas where cleaner fish were removed, 346 00:24:55,520 --> 00:24:58,840 three quarters of the fish population disappeared. 347 00:25:01,800 --> 00:25:03,960 It's assumed that many reef creatures 348 00:25:04,000 --> 00:25:06,720 would quickly succumb to disease and ill health 349 00:25:06,760 --> 00:25:08,800 if they were not regularly cleaned. 350 00:25:08,840 --> 00:25:11,960 So, it's no wonder these are popular places. 351 00:25:15,760 --> 00:25:18,320 The number of visitors at any one cleaning station 352 00:25:18,360 --> 00:25:21,000 could be well over 2,000 per day. 353 00:25:23,360 --> 00:25:25,720 And with up to 1,200 parasites being removed 354 00:25:25,760 --> 00:25:27,760 in a single fish cleaning session, 355 00:25:27,800 --> 00:25:32,000 it's a wonder these tiny shrimp can keep up with the demand. 356 00:25:39,080 --> 00:25:41,880 (STIRRING INSTRUMENTAL MUSIC) 357 00:25:41,920 --> 00:25:44,720 The Great Barrier Reef is perhaps best known 358 00:25:44,760 --> 00:25:48,000 for its profusion of small colourful fish. 359 00:25:49,480 --> 00:25:52,080 Great schools of anthias catch the sun 360 00:25:52,120 --> 00:25:54,280 in shades of peach and gold. 361 00:25:55,880 --> 00:25:58,400 Exotically named individuals 362 00:25:58,440 --> 00:26:01,600 like angelfish, sweetlip, and damselfish 363 00:26:01,640 --> 00:26:04,440 swim gracefully through the branching corals. 364 00:26:05,520 --> 00:26:08,720 The reef also provides a home for strange creatures 365 00:26:08,760 --> 00:26:12,120 like barrel sponges and giant clams. 366 00:26:14,600 --> 00:26:16,760 Many of the islands that rise from the reef 367 00:26:16,800 --> 00:26:19,960 are fringed by idyllic, icing sugarlike beaches... 368 00:26:24,480 --> 00:26:28,760 ..created by a creature in the sea, the bumphead parrotfish. 369 00:26:31,000 --> 00:26:33,120 This is the world's largest parrotfish, 370 00:26:33,160 --> 00:26:35,880 and its favourite food is coral. 371 00:26:37,960 --> 00:26:42,200 It uses the massive bump on its head to knock off big chunks of coral, 372 00:26:42,240 --> 00:26:46,320 and its beaklike mouth to crush and consume the spoils. 373 00:26:49,360 --> 00:26:51,520 The fish is actually only interested 374 00:26:51,560 --> 00:26:54,080 in the polyps and algae inside the coral, 375 00:26:54,120 --> 00:26:56,600 but to get that takes a bit of work. 376 00:26:58,920 --> 00:27:02,320 The crushed coral skeleton is then excreted as waste - 377 00:27:02,360 --> 00:27:07,360 waste that washes up onto atolls such as this as sand. 378 00:27:08,840 --> 00:27:12,160 Yes, that deliciously soft powder beneath your toes 379 00:27:12,200 --> 00:27:14,880 is mostly made from parrotfish poo. 380 00:27:17,280 --> 00:27:19,280 (STIRRING INSTRUMENTAL MUSIC) 381 00:27:19,320 --> 00:27:22,960 Studies in the Maldives have shown that 85% of the sand there 382 00:27:23,000 --> 00:27:25,920 has come from the rear end of parrotfish. 383 00:27:28,480 --> 00:27:31,800 (JAUNTY INSTRUMENTAL MUSIC) 384 00:27:33,600 --> 00:27:35,400 One type of fish that's well designed 385 00:27:35,440 --> 00:27:39,880 for living in inaccessible places on the reef is the moray eel. 386 00:27:50,520 --> 00:27:53,520 (JAUNTY MUSIC CONTINUES) 387 00:27:54,840 --> 00:27:57,680 These impressive fish can grow to three metres long 388 00:27:57,720 --> 00:28:00,120 and be as thick as a human waist. 389 00:28:01,400 --> 00:28:03,560 Despite these intimidating dimensions, 390 00:28:03,600 --> 00:28:06,400 moray eels are not aggressive to humans. 391 00:28:11,000 --> 00:28:12,920 Divers can come across morays 392 00:28:12,960 --> 00:28:15,960 in tropical and temperate waters around the globe, 393 00:28:16,000 --> 00:28:19,320 but northern Australia has 15 different species 394 00:28:19,360 --> 00:28:21,400 of this spectacular eel. 395 00:28:23,480 --> 00:28:27,320 It takes about 20 years for these eels to reach their full size. 396 00:28:30,120 --> 00:28:33,360 As this time approaches, many of them turn into females. 397 00:28:37,240 --> 00:28:41,240 Within a month of mating, however, they will lay their eggs and die. 398 00:28:47,480 --> 00:28:49,360 One remarkable species of eel 399 00:28:49,400 --> 00:28:52,240 was only discovered when scuba diving became popular. 400 00:28:53,560 --> 00:28:55,960 These eels live out on the open sand, 401 00:28:56,000 --> 00:29:00,040 so they've developed a unique method of remaining inconspicuous 402 00:29:00,080 --> 00:29:02,240 despite their obvious exposure. 403 00:29:03,560 --> 00:29:06,240 They simply pretend they're a field of seagrass. 404 00:29:07,720 --> 00:29:10,560 Spotted garden eels live in huge colonies 405 00:29:10,600 --> 00:29:12,960 on sunlit patches of the sea floor. 406 00:29:14,560 --> 00:29:17,720 Their range extends across the Indian Ocean to Africa, 407 00:29:17,760 --> 00:29:19,920 and up the Western Pacific to Japan. 408 00:29:21,640 --> 00:29:24,080 To feed, they rise out of their burrows 409 00:29:24,120 --> 00:29:26,320 and sway in the ocean currents, 410 00:29:26,360 --> 00:29:28,640 taking in zooplankton as they go. 411 00:29:30,320 --> 00:29:34,040 If alarmed, the eels instantly retreat into the seabed, 412 00:29:34,080 --> 00:29:38,200 and the sand appears as if no-one was ever there. 413 00:29:40,120 --> 00:29:43,280 (JAUNTY INSTRUMENTAL MUSIC) 414 00:29:47,240 --> 00:29:50,840 NARRATOR: The world's oceans are home to seven marine turtle species. 415 00:29:54,880 --> 00:29:56,880 One of the largest, the loggerhead, 416 00:29:56,920 --> 00:29:59,640 can tolerate the colder oceans of northern Europe 417 00:29:59,680 --> 00:30:00,840 and the South Atlantic. 418 00:30:03,520 --> 00:30:05,360 They can be found anywhere 419 00:30:05,400 --> 00:30:08,400 except the extreme conditions of the North and South Pole. 420 00:30:09,800 --> 00:30:11,280 They prefer coastal areas, 421 00:30:11,320 --> 00:30:14,120 but are often spotted travelling way out to sea. 422 00:30:17,200 --> 00:30:20,240 Hawksbill turtles avoid deep waters, 423 00:30:20,280 --> 00:30:24,160 and are usually found in the warm seas near coral reefs, 424 00:30:24,200 --> 00:30:28,160 where their favourite food, sponges, grows in large numbers. 425 00:30:30,880 --> 00:30:34,080 Their dramatic serrated shell and birdlike beak 426 00:30:34,120 --> 00:30:36,120 makes them easy to identify. 427 00:30:38,400 --> 00:30:41,960 The gentle green turtle is the most prolific and widespread. 428 00:30:43,560 --> 00:30:47,400 They live in and around the tropics, including Hawaii. 429 00:30:59,720 --> 00:31:01,920 Green turtles are not alarmed by divers, 430 00:31:01,960 --> 00:31:04,840 so it's often possible to swim right up to them 431 00:31:04,880 --> 00:31:06,920 to get a really close encounter. 432 00:31:09,400 --> 00:31:12,400 (GENTLE PIANO MUSIC) 433 00:31:16,200 --> 00:31:20,960 All marine turtles begin life in an egg buried in the sand. 434 00:31:22,600 --> 00:31:26,920 Their mothers make the laborious journey up the beach to dig a nest. 435 00:31:28,840 --> 00:31:32,160 Once she begins laying, she enters a trancelike state, 436 00:31:32,200 --> 00:31:37,560 where nothing, not even onlookers, will disrupt the job at hand. 437 00:31:40,840 --> 00:31:45,080 100 to 200 eggs later, depending on the species, 438 00:31:45,120 --> 00:31:49,400 mum covers the pit completely, then returns back to the sea. 439 00:31:51,840 --> 00:31:53,000 In the course of a season, 440 00:31:53,040 --> 00:31:56,880 a female green turtle may do this five or six times. 441 00:31:56,920 --> 00:32:01,200 Set and forget, and if all goes according to plan... 442 00:32:03,480 --> 00:32:05,680 ..six to eight weeks later, 443 00:32:05,720 --> 00:32:08,760 newly hatched turtles will begin to emerge. 444 00:32:10,120 --> 00:32:13,120 (GENTLE PIANO MUSIC) 445 00:32:16,600 --> 00:32:18,400 (HAUNTING INSTRUMENTAL MUSIC) 446 00:32:18,440 --> 00:32:23,040 As they make their way to the ocean, they run a veritable gauntlet, 447 00:32:23,080 --> 00:32:27,240 hoping to avoid predation by crabs hiding below the sand 448 00:32:27,280 --> 00:32:29,520 and birds wheeling overhead. 449 00:32:35,080 --> 00:32:38,000 Once they enter the water, it's game on, 450 00:32:38,040 --> 00:32:40,840 for hordes of hungry fish and ravenous sharks 451 00:32:40,880 --> 00:32:42,520 are patrolling the shallows. 452 00:32:43,600 --> 00:32:47,440 The odds of surviving are stacked against the hatchlings. 453 00:32:47,480 --> 00:32:50,400 Fewer than one in 1,000 survive, 454 00:32:50,440 --> 00:32:53,560 but if this little turtle can make it through the breakers 455 00:32:53,600 --> 00:32:55,600 and out to the open sea, 456 00:32:55,640 --> 00:32:58,720 its chances of surviving to adulthood are good. 457 00:33:00,560 --> 00:33:03,560 (GENTLE INSTRUMENTAL MUSIC) 458 00:33:03,600 --> 00:33:06,400 The years between hatching and reaching maturity 459 00:33:06,440 --> 00:33:08,600 are known as the lost years, 460 00:33:08,640 --> 00:33:11,880 for scientists are still trying to work out where they go. 461 00:33:13,040 --> 00:33:14,520 One thing's for certain, however. 462 00:33:14,560 --> 00:33:17,880 They have an inbuilt natural GPS 463 00:33:17,920 --> 00:33:21,200 that will guide them back to the same area where they were born 464 00:33:21,240 --> 00:33:23,640 when they are ready to breed themselves. 465 00:33:26,920 --> 00:33:28,720 Turtle populations around the world 466 00:33:28,760 --> 00:33:30,760 have taken a hammering over the years. 467 00:33:31,960 --> 00:33:34,360 They're regularly killed in discarded nets 468 00:33:34,400 --> 00:33:36,640 that drift silently through the sea... 469 00:33:38,440 --> 00:33:42,520 ..or starve to death after mistaking plastic shopping bags for jellyfish. 470 00:33:44,640 --> 00:33:48,880 Adding to their 21st-century woes, climate change. 471 00:33:50,480 --> 00:33:53,920 For the time being, however, turtles are still with us, 472 00:33:53,960 --> 00:33:57,080 and encountering these ancient mariners in the ocean 473 00:33:57,120 --> 00:34:00,600 remains an inspirational, uplifting experience. 474 00:34:05,200 --> 00:34:08,200 (MYSTICAL INSTRUMENTAL MUSIC) 475 00:34:11,360 --> 00:34:13,000 The island of Eil Malk, 476 00:34:13,040 --> 00:34:14,640 in the Pacific nation of Palau, 477 00:34:14,680 --> 00:34:17,040 is both beautiful and remote... 478 00:34:19,160 --> 00:34:22,880 ..and it affords one of the most ethereal animal encounters on Earth. 479 00:34:27,560 --> 00:34:31,480 The lifeforms that have developed here are truly mesmerising. 480 00:34:31,520 --> 00:34:33,560 Golden jellyfish. 481 00:34:35,120 --> 00:34:37,280 The reason people can safely swim here 482 00:34:37,320 --> 00:34:40,160 is that the jellyfish are not able to sting. 483 00:34:43,200 --> 00:34:45,000 Although the lake is saline, 484 00:34:45,040 --> 00:34:49,360 these jellyfish have been cut off from the sea for over 10,000 years. 485 00:34:51,920 --> 00:34:54,360 No open sea means no predators, 486 00:34:54,400 --> 00:34:58,120 and no predators means no need for defences. 487 00:35:01,560 --> 00:35:04,400 These jellyfish have well and truly let their guard down, 488 00:35:04,440 --> 00:35:07,840 and have gradually lost their ability to sting. 489 00:35:13,440 --> 00:35:16,480 The lake was formed when global sea levels rose 490 00:35:16,520 --> 00:35:18,000 after the last ice age. 491 00:35:19,480 --> 00:35:22,720 It's still connected to the neighbouring lagoon by three tunnels, 492 00:35:22,760 --> 00:35:25,720 so water washes in here with every high tide. 493 00:35:27,640 --> 00:35:31,440 Around eight million jellyfish live here when conditions are optimal. 494 00:35:33,360 --> 00:35:36,360 At last count, there were only about 600,000, 495 00:35:36,400 --> 00:35:40,200 but that's still a heck of a lot of jellyfish to contend with. 496 00:35:43,200 --> 00:35:45,200 No-one knows exactly why, 497 00:35:45,240 --> 00:35:49,000 but rainfall here is the lowest it's been in 65 years. 498 00:35:50,160 --> 00:35:53,840 As a result, the lake's salinity levels are the highest on record. 499 00:35:56,440 --> 00:35:58,320 It's too early for scientists to tell 500 00:35:58,360 --> 00:36:00,360 whether the reduced jellyfish numbers 501 00:36:00,400 --> 00:36:04,200 are a natural fluctuation or a result of climate change. 502 00:36:05,960 --> 00:36:09,000 The last population crash was in the 1990s 503 00:36:09,040 --> 00:36:10,920 after an El Nino event... 504 00:36:12,520 --> 00:36:15,680 ..and the good news is the jellyfish bounced back. 505 00:36:16,960 --> 00:36:20,680 Everyone here in Palau is hopeful the same thing will happen again. 506 00:36:28,520 --> 00:36:31,840 Of all the animal encounters possible in the marine environment, 507 00:36:31,880 --> 00:36:34,600 this one never fails to delight, 508 00:36:34,640 --> 00:36:38,640 causing many to spontaneously laugh out loud underwater. 509 00:36:42,200 --> 00:36:45,200 (GENTLE TINKLING MUSIC) 510 00:36:48,200 --> 00:36:51,840 Australian sealions may be one of the rarest species in the ocean, 511 00:36:51,880 --> 00:36:55,840 but these adolescent pups don't seem too concerned at all. 512 00:36:57,200 --> 00:36:58,720 They just want to play. 513 00:37:00,120 --> 00:37:01,680 These sublime animals 514 00:37:01,720 --> 00:37:03,240 live just off a remote beach 515 00:37:03,280 --> 00:37:04,760 on the Great Australian Bight 516 00:37:04,800 --> 00:37:06,360 called Baird Bay. 517 00:37:08,240 --> 00:37:11,440 The water can be cold, but if you're prepared to brave it, 518 00:37:11,480 --> 00:37:14,640 the welcome you'll receive is very warm indeed. 519 00:37:17,080 --> 00:37:19,640 There are only three rules to enjoying an encounter 520 00:37:19,680 --> 00:37:21,680 without upsetting the balance of nature. 521 00:37:24,440 --> 00:37:27,960 No sunscreen, no touching, and no chasing. 522 00:37:32,320 --> 00:37:36,000 Sealions differ from seals in two big ways. 523 00:37:36,040 --> 00:37:38,080 They have external ear flaps, 524 00:37:38,120 --> 00:37:40,440 and they can walk on their back flippers, 525 00:37:40,480 --> 00:37:43,280 using their front ones to prop them upright. 526 00:37:45,200 --> 00:37:47,520 There are only about 12,000 Australian sealions 527 00:37:47,560 --> 00:37:49,480 left in the world, 528 00:37:49,520 --> 00:37:53,640 but the local population here at Baird Bay is thriving. 529 00:37:53,680 --> 00:37:57,160 Since legislation has ensured their protection, 530 00:37:57,200 --> 00:37:59,680 numbers have increased threefold. 531 00:38:10,080 --> 00:38:14,280 Another spot in the southern oceans famous for its marine mammals 532 00:38:14,320 --> 00:38:17,680 lies on the other side of the Tasman Sea in New Zealand. 533 00:38:20,600 --> 00:38:22,160 Its standout feature, 534 00:38:22,200 --> 00:38:25,080 apart from the sheer beauty of the place above the waterline, 535 00:38:25,120 --> 00:38:27,840 is a gaping canyon just offshore, 536 00:38:27,880 --> 00:38:30,680 and it's a daunting 3km deep. 537 00:38:32,680 --> 00:38:34,840 Kaikoura is a former whaling station 538 00:38:34,880 --> 00:38:36,280 north of Christchurch 539 00:38:36,320 --> 00:38:38,680 on the South Island of New Zealand. 540 00:38:38,720 --> 00:38:42,440 The name means "crayfish food" in the local Maori language, 541 00:38:42,480 --> 00:38:45,720 and that provides a clue to the unusual abundance 542 00:38:45,760 --> 00:38:47,400 of sea life found here. 543 00:38:48,760 --> 00:38:51,200 The immense underwater canyon below these waves 544 00:38:51,240 --> 00:38:53,960 is rich with krill and other plankton. 545 00:38:55,360 --> 00:38:57,480 This, in turn, draws other sea animals 546 00:38:57,520 --> 00:38:59,520 all the way up the food chain. 547 00:39:01,720 --> 00:39:03,880 Some of the noisiest come here to breed. 548 00:39:05,880 --> 00:39:07,320 Fur seals. 549 00:39:07,360 --> 00:39:11,160 One male commands a harem of about 40 females, 550 00:39:11,200 --> 00:39:15,840 and he'll make a serious song and dance about keeping them for himself. 551 00:39:15,880 --> 00:39:18,960 It's a hard life for a female fur seal. 552 00:39:19,000 --> 00:39:23,120 They give birth, and almost immediately fall pregnant again, 553 00:39:23,160 --> 00:39:28,960 and year after year, they return to Kaikoura to repeat the cycle. 554 00:39:41,040 --> 00:39:44,440 Of equal interest to animal lovers is the sperm whale. 555 00:39:46,120 --> 00:39:49,800 The animal with the largest brain of any creature known to have lived. 556 00:39:51,200 --> 00:39:54,520 Its tail fluke is over four metres across, 557 00:39:54,560 --> 00:39:59,160 driving these enormous animals along at nearly 40km per hour. 558 00:40:01,880 --> 00:40:03,880 This is one of the few places in the world 559 00:40:03,920 --> 00:40:07,520 where sperm whales can be seen so close to shore. 560 00:40:11,522 --> 00:40:15,202 NARRATOR: If size really matters when it comes to animal encounters, 561 00:40:15,242 --> 00:40:18,562 then you really can't overlook the blue whale, 562 00:40:18,602 --> 00:40:21,482 the largest animal in the ocean. 563 00:40:21,522 --> 00:40:24,922 In fact, it's the largest animal that has ever lived. 564 00:40:26,162 --> 00:40:28,722 There are two world-renowned places for seeing them. 565 00:40:28,762 --> 00:40:30,722 One is the Monterey Canyon, 566 00:40:30,762 --> 00:40:33,042 off the coast of California, in the USA, 567 00:40:33,082 --> 00:40:35,562 the other is the east coast of Australia. 568 00:40:38,482 --> 00:40:40,282 Between May and November, 569 00:40:40,322 --> 00:40:43,722 these iconic animals migrate along the coastline. 570 00:40:43,762 --> 00:40:46,962 They're travelling from the rich food sources in the Antarctic 571 00:40:47,002 --> 00:40:49,082 to warmer waters for breeding. 572 00:40:51,402 --> 00:40:55,122 To see one in the wild is an unforgettable experience, 573 00:40:55,162 --> 00:40:56,642 even from the air. 574 00:40:59,282 --> 00:41:02,722 Fully grown blue whales are roughly 30 metres long. 575 00:41:02,762 --> 00:41:05,522 Their heart alone is as big as a car, 576 00:41:05,562 --> 00:41:08,482 and yet they feed exclusively on krill, 577 00:41:08,522 --> 00:41:12,722 tiny shrimplike organisms that have a colossal significance in the sea, 578 00:41:12,762 --> 00:41:16,162 forming the basis for many marine food webs. 579 00:41:19,362 --> 00:41:21,762 Apart from being the biggest animals on the planet, 580 00:41:21,802 --> 00:41:24,802 blue whales are also one of the loudest. 581 00:41:24,842 --> 00:41:29,682 They communicate using low groans, grunts, and pulsing sounds... 582 00:41:31,482 --> 00:41:35,282 ..and they can hear each other from 1,600km away. 583 00:41:44,242 --> 00:41:48,482 Humpback whales are a far easier species to encounter in the wild 584 00:41:48,522 --> 00:41:52,042 in glorious places such as this. 585 00:41:52,082 --> 00:41:55,922 The Inside Passage is a well known coastal route 586 00:41:55,962 --> 00:41:57,962 that weaves its way through the islands 587 00:41:58,002 --> 00:42:00,042 on the Pacific Coast of North America. 588 00:42:03,762 --> 00:42:05,282 Humpbacks will outperform 589 00:42:05,322 --> 00:42:07,482 just about any other whale species in the ocean... 590 00:42:09,122 --> 00:42:11,242 ..and are regularly seen waving their fins 591 00:42:11,282 --> 00:42:12,882 as if to attract attention, 592 00:42:12,922 --> 00:42:15,162 or breaching clean out of the sea. 593 00:42:17,002 --> 00:42:20,602 They are a migratory species, and travel further than most, 594 00:42:20,642 --> 00:42:23,202 feeding in Antarctica in the summer months 595 00:42:23,242 --> 00:42:25,642 before heading to warmer climes to breed. 596 00:42:27,162 --> 00:42:29,762 They are thought to live up to 50 years, 597 00:42:29,802 --> 00:42:33,602 and the age of a whale can be measured in much the same way 598 00:42:33,642 --> 00:42:35,842 foresters are able to age trees. 599 00:42:35,882 --> 00:42:39,042 When scientists discover a dead whale, 600 00:42:39,082 --> 00:42:41,762 they remove the waxy plugs from its ears 601 00:42:41,802 --> 00:42:44,402 and simply count the number of rings. 602 00:42:46,402 --> 00:42:48,962 (GENTLE INSTRUMENTAL MUSIC) 603 00:42:52,442 --> 00:42:56,042 The Kingdom of Tonga, a collection of 170 islands 604 00:42:56,082 --> 00:42:57,442 lying right in the middle 605 00:42:57,482 --> 00:42:59,482 of the vast Pacific Ocean, 606 00:42:59,522 --> 00:43:00,922 offers an even closer 607 00:43:00,962 --> 00:43:02,362 encounter with whales. 608 00:43:05,962 --> 00:43:08,882 Hundreds of humpbacks choose to come here every year 609 00:43:08,922 --> 00:43:10,402 to raise their young. 610 00:43:10,442 --> 00:43:12,482 From July through to November, 611 00:43:12,522 --> 00:43:15,402 the humpback females stay here to give birth 612 00:43:15,442 --> 00:43:17,242 and nurture their calves. 613 00:43:17,282 --> 00:43:20,082 The females fast while they are nursing young, 614 00:43:20,122 --> 00:43:24,882 who greedily consume up to 600 litres of thick rich milk a day... 615 00:43:26,322 --> 00:43:29,962 ..and they don't seem to be bothered by humans dropping in for a visit. 616 00:43:32,602 --> 00:43:35,602 It's a truly magical marine experience. 617 00:43:38,802 --> 00:43:41,042 Mothers and their young swim close together, 618 00:43:41,082 --> 00:43:43,482 often touching each other with their flippers 619 00:43:43,522 --> 00:43:45,002 as a sign of affection. 620 00:43:46,482 --> 00:43:49,642 It will take ten years for these calves to be fully grown, 621 00:43:49,682 --> 00:43:53,202 and they will stay close to their mothers for much of this time. 622 00:44:02,642 --> 00:44:05,642 (SWEEPING ORCHESTRAL MUSIC) 623 00:44:07,122 --> 00:44:11,922 It is clear we humans pose less of a threat to animals underwater 624 00:44:11,962 --> 00:44:13,642 than we do above it. 625 00:44:13,682 --> 00:44:16,042 We swim slowly, 626 00:44:16,082 --> 00:44:19,882 and of course, we can't stay forever in their ocean realm. 627 00:44:21,362 --> 00:44:23,442 We would appear to be a curiosity, 628 00:44:23,482 --> 00:44:25,802 rather than a threat to marine animals, 629 00:44:25,842 --> 00:44:28,042 so they often allow us to get much closer to them 630 00:44:28,082 --> 00:44:29,722 than land animals do... 631 00:44:31,962 --> 00:44:35,802 ..and that, in essence, is what makes marine encounters 632 00:44:35,842 --> 00:44:40,122 some of the most spectacular wildlife experiences of all. 633 00:44:41,962 --> 00:44:44,962 Captioned by Ai-Media ai-media.tv