1 00:00:17,800 --> 00:00:20,280 The natural world is full of colours... 2 00:00:27,080 --> 00:00:29,240 ..colours that attract attention... 3 00:00:35,160 --> 00:00:38,040 ..colours that blend beautifully with their background... 4 00:00:41,760 --> 00:00:45,160 ..and colours that create extraordinary displays. 5 00:00:51,280 --> 00:00:54,720 There are few animals more brilliantly coloured than 6 00:00:54,720 --> 00:00:56,360 these scarlet macaws. 7 00:00:57,600 --> 00:01:01,680 Animals can use colour for all kinds of different reasons, 8 00:01:01,680 --> 00:01:05,360 and some have colours that we ourselves can't even see. 9 00:01:08,360 --> 00:01:12,640 But with new cameras, some developed especially for this series, 10 00:01:12,640 --> 00:01:16,760 we can reveal a world that has long been hidden from our eyes... 11 00:01:18,960 --> 00:01:22,360 ..a world of colours that only some animals can see. 12 00:01:24,160 --> 00:01:29,600 Secret communication channels for the most private of messages, 13 00:01:29,600 --> 00:01:33,520 and colours so bold and brilliant they dazzle our senses. 14 00:01:36,600 --> 00:01:37,920 Whether to win a mate... 15 00:01:40,040 --> 00:01:41,240 ..or beat a rival... 16 00:01:43,240 --> 00:01:44,560 ..to warn off an enemy... 17 00:01:46,480 --> 00:01:47,920 ..or to hide from one... 18 00:01:53,040 --> 00:01:57,640 ..we will reveal extraordinary stories about life in colour. 19 00:02:23,680 --> 00:02:26,320 The rocky hills of Southern India. 20 00:02:34,880 --> 00:02:38,160 The stage is set for a performance of one 21 00:02:38,160 --> 00:02:41,960 of the most spectacular dances in the natural world. 22 00:02:41,960 --> 00:02:44,240 PEACOCKS CALL 23 00:02:47,040 --> 00:02:48,680 Peacocks are gathering. 24 00:03:03,320 --> 00:03:08,160 This, surely, is one of the most glamorous of all sights in nature. 25 00:03:16,320 --> 00:03:20,000 150 shimmering eyespots, 26 00:03:20,000 --> 00:03:23,200 carried on tail feathers that are six feet long. 27 00:03:33,760 --> 00:03:36,840 So how did such glories evolve? 28 00:03:41,160 --> 00:03:44,080 It seems it's all down to the female. 29 00:03:48,040 --> 00:03:49,400 HE CALLS 30 00:03:52,280 --> 00:03:56,160 The brighter a male's colours and the greater the number of 31 00:03:56,160 --> 00:04:00,160 his feathery eyespots, the more attractive she will find him. 32 00:04:13,120 --> 00:04:16,840 But colours and plumes like these come at a cost. 33 00:04:25,040 --> 00:04:28,240 The immense tail makes flying difficult - 34 00:04:28,240 --> 00:04:31,600 the males are literally weighed down by their feathers. 35 00:04:36,160 --> 00:04:39,560 Yet the colours they carry are clearly very important to them. 36 00:04:42,240 --> 00:04:45,760 So why and how has colour taken on such value? 37 00:04:53,200 --> 00:04:58,560 To understand that, we have to think back to when it all began. 38 00:05:02,840 --> 00:05:07,400 700 million years ago, our planet was far less colourful. 39 00:05:09,240 --> 00:05:11,520 But the first animals, it seems, 40 00:05:11,520 --> 00:05:15,440 had eyes that were unable to distinguish colours anyway. 41 00:05:17,960 --> 00:05:20,400 Gradually, however, this changed. 42 00:05:27,120 --> 00:05:28,680 I am in Costa Rica... 43 00:05:31,120 --> 00:05:34,480 ..a good place to see how valuable colour can be. 44 00:05:38,920 --> 00:05:43,800 This toucan likes fruit, and its ability to choose ripe 45 00:05:43,800 --> 00:05:49,440 fruit from unripe depends on colour because the ripe ones are black. 46 00:05:51,720 --> 00:05:55,680 And this capacity of choosing between different colours was 47 00:05:55,680 --> 00:05:59,880 a very important stage in the evolution of colour vision. 48 00:06:06,520 --> 00:06:11,280 Birds, close relatives of dinosaurs, appeared before mammals. 49 00:06:16,120 --> 00:06:20,320 The first mammals, as far as we can tell, were mostly nocturnal. 50 00:06:21,600 --> 00:06:24,640 Colours are not easily distinguishable at night, 51 00:06:24,640 --> 00:06:26,960 so why evolve the ability to detect them? 52 00:06:30,720 --> 00:06:35,360 So it seems that the first mammals themselves were not very colourful. 53 00:06:36,840 --> 00:06:39,320 And this is still largely true today. 54 00:06:43,720 --> 00:06:46,120 Most are shades of black and white... 55 00:06:47,640 --> 00:06:48,760 ..or brown. 56 00:06:52,640 --> 00:06:54,200 But there are exceptions. 57 00:06:55,520 --> 00:06:59,280 And one of the most dramatic lives in the forests of Gabon 58 00:06:59,280 --> 00:07:00,280 in West Africa. 59 00:07:15,920 --> 00:07:19,240 These monkeys are mandrills - a kind of baboon. 60 00:07:20,520 --> 00:07:22,040 They live in large troops. 61 00:07:23,760 --> 00:07:28,160 Most are females and youngsters, both of which are brown. 62 00:07:32,240 --> 00:07:34,080 But the males are different. 63 00:07:37,960 --> 00:07:42,400 They, when they're young, have very plain faces with naked muzzles. 64 00:07:47,520 --> 00:07:50,520 As they grow, their faces begin to change. 65 00:07:53,400 --> 00:07:56,400 Testosterone begins to flow through their veins. 66 00:08:02,600 --> 00:08:06,160 When they're about six years old, they leave the troop 67 00:08:06,160 --> 00:08:08,160 and start to fend for themselves. 68 00:08:09,520 --> 00:08:13,920 As they become sexually mature, colour appears in their faces... 69 00:08:15,720 --> 00:08:17,360 ..and what colour! 70 00:08:26,920 --> 00:08:30,360 Mandrill males are the biggest of all monkeys... 71 00:08:32,360 --> 00:08:34,600 ..weighing over 30 kilos - 72 00:08:34,600 --> 00:08:38,200 enormously, frighteningly powerful. 73 00:08:38,200 --> 00:08:39,480 And their colours say so. 74 00:08:42,520 --> 00:08:44,440 SCREECHING 75 00:08:45,360 --> 00:08:46,480 HISSING 76 00:08:48,360 --> 00:08:51,160 It is not only his face which is coloured. 77 00:08:53,640 --> 00:08:54,920 So is his rump. 78 00:08:56,360 --> 00:09:00,680 Both are fearless declarations of his health and strength. 79 00:09:04,720 --> 00:09:09,080 And this male is more than happy to prove just how strong he is... 80 00:09:09,080 --> 00:09:11,880 ..should any male dare to challenge him. 81 00:09:16,520 --> 00:09:20,520 Not surprisingly, mandrill eyes are particularly sensitive to colour. 82 00:09:24,960 --> 00:09:28,440 And it's the brightness of their colours which signals their status. 83 00:09:34,120 --> 00:09:35,320 SCREECHING 84 00:09:38,960 --> 00:09:41,440 There are four males in this troop, 85 00:09:41,440 --> 00:09:43,560 and they're constantly flexing their muscles 86 00:09:43,560 --> 00:09:47,720 and displaying their colours to establish who is the strongest. 87 00:09:51,440 --> 00:09:54,480 And not all disputes are settled peacefully. 88 00:10:00,920 --> 00:10:03,720 They emphasise their ferocity by gestures 89 00:10:03,720 --> 00:10:05,640 such as grinding their teeth. 90 00:10:13,360 --> 00:10:17,000 If that doesn't work, the highest-ranking male will fight... 91 00:10:19,440 --> 00:10:21,040 ..and the others know it. 92 00:10:25,760 --> 00:10:28,360 It's better to let colour do the talking. 93 00:10:30,600 --> 00:10:31,800 HE COUGHS 94 00:10:36,720 --> 00:10:39,960 Mandrills see the world much as we do 95 00:10:39,960 --> 00:10:42,760 and have three kinds of colour-sensitive cells. 96 00:10:46,280 --> 00:10:50,120 But another group of animals has colour vision that's far 97 00:10:50,120 --> 00:10:53,960 superior to that of any mammal - birds. 98 00:11:00,800 --> 00:11:04,400 Their ability varies from group to group, 99 00:11:04,400 --> 00:11:07,160 but you can judge how good they are from the colours 100 00:11:07,160 --> 00:11:09,160 they use to signal to one another. 101 00:11:11,520 --> 00:11:14,680 Hummingbirds have excellent colour vision... 102 00:11:16,240 --> 00:11:21,400 ..because that enables them to spot brightly-coloured flowers 103 00:11:21,400 --> 00:11:23,800 which contains the nectar on which they feed. 104 00:11:32,760 --> 00:11:36,760 So this artificial feeder is a big success - 105 00:11:36,760 --> 00:11:39,080 brightly coloured down here, 106 00:11:39,080 --> 00:11:42,600 and containing sugar solution, artificial nectar, up there. 107 00:11:48,840 --> 00:11:51,920 But hummingbirds also use their ability to see 108 00:11:51,920 --> 00:11:55,880 colour in a different way - to attract a mate. 109 00:11:58,480 --> 00:12:01,200 Most species live in South America, where 110 00:12:01,200 --> 00:12:04,400 there are flowers of some sort all year round. 111 00:12:08,120 --> 00:12:10,560 A few, however, have spread northwards 112 00:12:10,560 --> 00:12:13,280 into the deserts of the American Southwest. 113 00:12:17,680 --> 00:12:21,800 In this vastness, it's hard to get noticed... 114 00:12:24,160 --> 00:12:28,120 ..especially if you are a small hummingbird looking for a mate. 115 00:12:41,040 --> 00:12:46,280 But this male Costa's hummingbird uses his colours to send 116 00:12:46,280 --> 00:12:47,200 a secret message. 117 00:12:50,760 --> 00:12:55,440 Out in the open, flashy colours can attract unwanted attention, 118 00:12:55,440 --> 00:12:58,040 so he keeps them hidden most of the time. 119 00:13:00,280 --> 00:13:02,240 A slight turn of the head, however, 120 00:13:02,240 --> 00:13:05,800 provides a tantalising glimpse of what he has to offer. 121 00:13:10,880 --> 00:13:13,200 He's spotted a female. 122 00:13:13,200 --> 00:13:14,080 She's feeding. 123 00:13:20,920 --> 00:13:25,480 Hummingbirds live fast lives and need plenty of fuel. 124 00:13:25,480 --> 00:13:27,920 So, if he is to attract her attention, 125 00:13:27,920 --> 00:13:30,240 he needs something eye-catching. 126 00:13:36,040 --> 00:13:38,880 Time to reveal his colours! 127 00:13:42,440 --> 00:13:45,640 Erecting the iridescent feathers on his neck, 128 00:13:45,640 --> 00:13:48,440 he positions himself to catch the sunlight. 129 00:13:55,920 --> 00:13:59,520 Seen at just the right angle, his colours are dazzling. 130 00:14:19,200 --> 00:14:22,200 Aerobatics like these take a lot of energy, 131 00:14:22,200 --> 00:14:26,280 so his performance can give her clues about his health and fitness. 132 00:14:31,520 --> 00:14:36,640 Every second she takes to decide burns up his energy reserves... 133 00:14:42,080 --> 00:14:44,280 ..so he can only hover for so long. 134 00:15:02,760 --> 00:15:06,640 At last, his colours have persuaded her. 135 00:15:16,280 --> 00:15:19,440 Displaying your colours is easy out in the open. 136 00:15:24,200 --> 00:15:26,760 Birds which live in dark forests, however, 137 00:15:26,760 --> 00:15:29,200 have to work harder to get noticed. 138 00:15:35,080 --> 00:15:38,080 The rainforests of New Guinea. 139 00:15:38,080 --> 00:15:40,840 Here, the trees stand 100 feet tall, 140 00:15:40,840 --> 00:15:44,200 with their crowns forming a near continuous canopy. 141 00:15:47,080 --> 00:15:50,320 But here and there, there's a small gap through which 142 00:15:50,320 --> 00:15:53,600 a shaft of light illuminates a patch on the forest floor... 143 00:15:57,040 --> 00:15:59,360 ..a stage for one of the most versatile 144 00:15:59,360 --> 00:16:01,280 dancers in the natural world... 145 00:16:05,240 --> 00:16:06,560 ..a bird of paradise. 146 00:16:08,600 --> 00:16:10,840 There are over 30 different species. 147 00:16:10,840 --> 00:16:12,680 This one, understandably, 148 00:16:12,680 --> 00:16:16,120 is called the magnificent bird of paradise. 149 00:16:17,720 --> 00:16:18,720 A male. 150 00:16:22,240 --> 00:16:25,840 Before starting his show, he clears his stage. 151 00:16:27,920 --> 00:16:31,640 The bare brown earth will make his colours stand out better. 152 00:16:46,640 --> 00:16:51,280 He takes particular care to remove anything green. 153 00:16:51,280 --> 00:16:54,640 That colour will be the main feature of his display, 154 00:16:54,640 --> 00:16:56,560 and he doesn't want any competition. 155 00:17:00,640 --> 00:17:02,200 Satisfied at last. 156 00:17:03,880 --> 00:17:07,880 A sapling in the centre will serve as his dancing pole. 157 00:17:13,480 --> 00:17:15,640 His costume must be immaculate. 158 00:17:17,480 --> 00:17:19,720 Plumes like these need careful attention. 159 00:17:32,680 --> 00:17:34,720 Time to summon the audience. 160 00:17:36,600 --> 00:17:43,840 HE CHIRPS 161 00:17:48,440 --> 00:17:50,560 HE CHIRPS 162 00:17:56,000 --> 00:17:59,080 The first to appear are all young males. 163 00:18:01,560 --> 00:18:05,520 They won't develop their colours until they're seven years old. 164 00:18:05,520 --> 00:18:07,840 They have come to watch and to learn. 165 00:18:09,680 --> 00:18:12,680 HE CHIRPS 166 00:18:14,120 --> 00:18:15,640 At last, a female. 167 00:18:16,800 --> 00:18:19,600 She looks much like a young male to our eyes... 168 00:18:21,600 --> 00:18:23,680 ..but he can clearly tell the difference. 169 00:18:28,720 --> 00:18:30,920 She will judge him by his performance 170 00:18:30,920 --> 00:18:33,200 and the brightness of his feathers. 171 00:18:35,680 --> 00:18:38,480 She does that from directly above him. 172 00:18:52,800 --> 00:18:57,520 He puffs up his feathers and swings round to show her his colours. 173 00:19:03,640 --> 00:19:07,680 For years, naturalists only watched his performance from ground level. 174 00:19:14,120 --> 00:19:16,680 But the female does so from above. 175 00:19:22,080 --> 00:19:25,680 And from there, his brilliant green colours stand out 176 00:19:25,680 --> 00:19:27,680 vividly against the brown of the ground. 177 00:19:32,360 --> 00:19:37,080 A pair of bare, quivering quills sprouting from his tail 178 00:19:37,080 --> 00:19:38,480 add to the excitement. 179 00:19:43,600 --> 00:19:47,920 This is one of the most complex of all courtship dances, and we're 180 00:19:47,920 --> 00:19:51,960 still unaware of the details that she may regard as critical. 181 00:20:02,960 --> 00:20:06,040 The prize-giving, however, is unmistakable. 182 00:20:19,680 --> 00:20:22,160 The colour vision of birds is mostly excellent. 183 00:20:24,720 --> 00:20:27,400 But that of many insects is almost as good. 184 00:20:34,800 --> 00:20:35,800 Butterflies. 185 00:20:42,440 --> 00:20:47,080 They too have evolved an astonishing variety of colours and patterns. 186 00:20:59,960 --> 00:21:05,000 The wings are covered by tiny scales like tiles on a roof, 187 00:21:05,000 --> 00:21:07,520 and it's they that produce some of the colours. 188 00:21:12,160 --> 00:21:13,520 Some have pigments. 189 00:21:15,200 --> 00:21:20,440 Others reflect light to produce a shimmering iridescence with 190 00:21:20,440 --> 00:21:24,240 colours that change according to the angle from which they are viewed. 191 00:21:37,240 --> 00:21:42,120 But some butterflies use colours that are invisible to our eyes. 192 00:21:51,280 --> 00:21:55,920 The glorious colours of an English meadow in bloom is 193 00:21:55,920 --> 00:21:58,160 a delight to the eyes of many of us. 194 00:21:59,440 --> 00:22:03,200 But their purpose is not to appeal to us - 195 00:22:03,200 --> 00:22:07,760 it's to attract insects, such as butterflies and bees. 196 00:22:10,120 --> 00:22:15,760 Most of these plants depend on insects to pollinate them, 197 00:22:15,760 --> 00:22:19,320 and they use their bright colours in order to attract insects. 198 00:22:20,480 --> 00:22:24,400 But to understand what an insect sees, 199 00:22:24,400 --> 00:22:27,840 we have to be able to see it through their eyes and from 200 00:22:27,840 --> 00:22:32,400 their perspective, and happily we've got a camera that enables us 201 00:22:32,400 --> 00:22:33,520 to do just that. 202 00:22:38,200 --> 00:22:40,320 This camera set-up lets us look at 203 00:22:40,320 --> 00:22:42,480 that flower in two different ways. 204 00:22:43,880 --> 00:22:46,560 This camera is an ultraviolet camera 205 00:22:46,560 --> 00:22:49,120 because it has a filter there that 206 00:22:49,120 --> 00:22:52,080 only lets through ultraviolet light. 207 00:22:52,080 --> 00:22:54,440 But at the same time, this filter 208 00:22:54,440 --> 00:22:56,720 also reflects normal light, 209 00:22:56,720 --> 00:23:00,920 and that comes into this camera, and that shows what we can see. 210 00:23:00,920 --> 00:23:05,560 So I can compare the two very easily. That's what we can see... 211 00:23:09,480 --> 00:23:11,240 ..and that's what the insect sees. 212 00:23:14,280 --> 00:23:17,360 Flowers have evolved these ultraviolet markings 213 00:23:17,360 --> 00:23:20,840 for the benefit of insects, such as butterflies. 214 00:23:30,240 --> 00:23:35,280 This particular one lives in the rainforests of eastern Australia. 215 00:23:35,280 --> 00:23:38,480 It's a blue moon butterfly - a male. 216 00:23:44,080 --> 00:23:48,520 You might not think that it's the most colourful you've ever seen 217 00:23:48,520 --> 00:23:53,560 but, with our ultraviolet camera, his wings take on a magical look. 218 00:23:59,680 --> 00:24:01,360 The brighter his patches, 219 00:24:01,360 --> 00:24:03,520 the more attractive he is to females. 220 00:24:08,920 --> 00:24:11,680 But ultraviolet markings like these can also 221 00:24:11,680 --> 00:24:14,400 be seen by the blue moon's main predators. 222 00:24:17,560 --> 00:24:20,160 Birds can see them just as clearly. 223 00:24:24,240 --> 00:24:28,360 So flying around with a bright signal like that on your wings 224 00:24:28,360 --> 00:24:29,360 could be dangerous. 225 00:24:35,960 --> 00:24:40,120 For a male, however, it's worth living dangerously. 226 00:24:40,120 --> 00:24:44,120 If he can mate with one or two females in his short lifetime, 227 00:24:44,120 --> 00:24:46,000 his colours will have been a success. 228 00:24:54,280 --> 00:24:55,920 But he has competition. 229 00:24:57,920 --> 00:25:01,880 He will have to defend his territory if he is to secure a mate. 230 00:25:05,440 --> 00:25:09,320 Butterfly wings are fragile, so physical combat is to be avoided. 231 00:25:12,560 --> 00:25:16,600 Disputes instead are settled with aerial displays. 232 00:25:34,240 --> 00:25:36,280 Time to show her his colours. 233 00:25:55,360 --> 00:25:58,440 In her eyes, he's simply dazzling. 234 00:26:14,200 --> 00:26:19,240 Ultraviolet colours are part of the spectrum that insects can see... 235 00:26:19,240 --> 00:26:20,400 ..and we cannot. 236 00:26:23,240 --> 00:26:26,840 Recent discoveries have revealed that some animals can also 237 00:26:26,840 --> 00:26:30,400 see a characteristic of light that we cannot detect. 238 00:26:32,760 --> 00:26:37,640 Sunlight contains rays that vibrate in many different planes. 239 00:26:38,960 --> 00:26:42,560 In polarised light, they vibrate in only one. 240 00:26:44,400 --> 00:26:47,040 Light may become polarised 241 00:26:47,040 --> 00:26:49,960 when reflected off a shiny surface, such as water. 242 00:26:51,720 --> 00:26:56,280 Unlike us, some animals can see polarised light, 243 00:26:56,280 --> 00:26:59,080 and they can exploit it in many ways. 244 00:27:04,120 --> 00:27:06,160 One creature that does so 245 00:27:06,160 --> 00:27:10,280 lives on these vast mudflats in northern Australia. 246 00:27:15,760 --> 00:27:20,240 These eyes - on stalks - belong to a male fiddler crab. 247 00:27:23,320 --> 00:27:26,040 And they can see in a way that we cannot. 248 00:27:34,400 --> 00:27:38,200 As the tide goes out, the crabs emerge from their burrows. 249 00:27:46,560 --> 00:27:50,800 His giant claw is too large to be used in feeding. 250 00:27:53,880 --> 00:27:57,920 Instead, he uses it to attract the attention of females... 251 00:27:57,920 --> 00:28:00,000 ..by waving it with vigour! 252 00:28:03,200 --> 00:28:06,840 The crabs can see objects that are close to them reasonably well... 253 00:28:09,960 --> 00:28:13,440 ..but their long-distance eyesight is not so good. 254 00:28:18,480 --> 00:28:21,840 Polarised light can help solve the problem. 255 00:28:26,440 --> 00:28:29,880 Viewed with a new specialist camera, the mudflats, 256 00:28:29,880 --> 00:28:33,040 which reflect polarised light, are bright... 257 00:28:36,160 --> 00:28:40,840 ..while the unpolarised crabs appear darker against their background. 258 00:28:42,720 --> 00:28:46,880 This striking contrast also makes the large claw more obvious. 259 00:28:49,960 --> 00:28:54,200 The big claw is also used by the male to defend his burrow. 260 00:28:59,080 --> 00:29:01,280 Not everyone heeds the warning. 261 00:29:16,000 --> 00:29:17,120 Battle over. 262 00:29:20,280 --> 00:29:23,560 But there are more dangerous enemies to face - 263 00:29:23,560 --> 00:29:24,880 aerial predators. 264 00:29:26,480 --> 00:29:29,760 The quicker they can spot them, the better 265 00:29:29,760 --> 00:29:33,520 and, once again, polarised light helps them to do so. 266 00:29:47,240 --> 00:29:51,480 With the coast clear, a male re-emerges from his burrow. 267 00:29:55,320 --> 00:29:57,160 At last, a female. 268 00:30:04,120 --> 00:30:08,120 With the tide on the turn, he must work fast to win her over. 269 00:30:15,280 --> 00:30:18,080 And close up, his colours come into play. 270 00:30:19,560 --> 00:30:23,560 The brightness of his blue back could be the deciding factor. 271 00:30:32,920 --> 00:30:34,880 She may not look willing, 272 00:30:34,880 --> 00:30:38,800 but the pushing and shoving are all part of the mating ritual. 273 00:30:43,680 --> 00:30:46,520 One last shove and she's in... 274 00:30:49,760 --> 00:30:50,920 ..just in time. 275 00:31:05,360 --> 00:31:09,600 On land, colour is used in a multitude of different ways. 276 00:31:10,720 --> 00:31:13,960 The same is true in the sea, but there, 277 00:31:13,960 --> 00:31:16,480 colour works in a very different way. 278 00:31:26,920 --> 00:31:30,000 This is Australia's Great Barrier Reef, 279 00:31:30,000 --> 00:31:33,440 and its shallow waters are full of vivid colour. 280 00:31:39,760 --> 00:31:43,480 The inhabitants of the reef exploit it to the full, 281 00:31:43,480 --> 00:31:46,200 with unparalleled and dazzling effect. 282 00:32:02,960 --> 00:32:06,760 The orange-red stripes of the harlequin tuskfish 283 00:32:06,760 --> 00:32:08,240 make it very conspicuous. 284 00:32:12,480 --> 00:32:14,760 But as light filters down through the water, 285 00:32:14,760 --> 00:32:17,720 more and more of its wavelengths are absorbed... 286 00:32:19,360 --> 00:32:21,800 ..and red is the first to disappear. 287 00:32:24,160 --> 00:32:27,320 So, as the harlequin swims downwards, 288 00:32:27,320 --> 00:32:31,120 his brilliantly coloured red body looks duller and duller. 289 00:32:42,720 --> 00:32:47,600 Different colours are absorbed at different rates in the sea, 290 00:32:47,600 --> 00:32:50,440 but some can still be seen at greater depths. 291 00:32:54,280 --> 00:32:56,760 Yellow and blue travel farthest, 292 00:32:56,760 --> 00:33:01,320 so it's these that many fish down here use to signal their identity. 293 00:33:07,560 --> 00:33:10,960 Most fish near the surface have good colour vision, 294 00:33:10,960 --> 00:33:15,400 but some of the smaller species can also see ultraviolet colours. 295 00:33:19,520 --> 00:33:23,120 To us, these yellow damselfish all look very similar. 296 00:33:28,160 --> 00:33:33,120 But using our ultraviolet camera here in controlled conditions, 297 00:33:33,120 --> 00:33:36,480 we can see that many fish have different patterns 298 00:33:36,480 --> 00:33:39,280 that are normally invisible to our eyes. 299 00:33:42,600 --> 00:33:44,920 And suddenly, it becomes clear that 300 00:33:44,920 --> 00:33:48,800 these two individuals are in fact different species. 301 00:33:52,920 --> 00:33:56,440 This lemon damselfish has distinctive spots 302 00:33:56,440 --> 00:33:57,600 on its gill covers. 303 00:34:00,240 --> 00:34:03,600 And this, an Ambon damsel, 304 00:34:03,600 --> 00:34:08,440 has bright reflecting ultraviolet patches all across the body. 305 00:34:11,200 --> 00:34:13,600 It's a code invisible to us 306 00:34:13,600 --> 00:34:16,320 that allows these fish to recognise each other... 307 00:34:18,840 --> 00:34:22,080 ..without attracting the attention of large predators, 308 00:34:22,080 --> 00:34:24,880 which can't see in the ultraviolet range. 309 00:34:32,960 --> 00:34:35,720 And it's on the seabed that you can find 310 00:34:35,720 --> 00:34:38,280 one of the most colourful sea creatures of all... 311 00:34:44,800 --> 00:34:47,440 ..the peacock mantis shrimp. 312 00:34:53,600 --> 00:34:56,400 This strange-looking creature's ancestry 313 00:34:56,400 --> 00:34:59,320 can be traced back 400 million years... 314 00:35:01,680 --> 00:35:05,320 ..and it has one of the most versatile kinds of eyes in the whole 315 00:35:05,320 --> 00:35:06,920 of the animal kingdom. 316 00:35:12,080 --> 00:35:17,120 It can rotate its two huge eyes independently of each other 317 00:35:17,120 --> 00:35:18,720 and in almost any direction. 318 00:35:21,480 --> 00:35:25,480 We have three kinds of colour receptors, but the mantis shrimp 319 00:35:25,480 --> 00:35:29,400 has 12, each with a direct link to the brain, 320 00:35:29,400 --> 00:35:33,120 so it can perceive colour faster than any other animal. 321 00:35:35,400 --> 00:35:39,040 And it can also detect the difference between polarised 322 00:35:39,040 --> 00:35:40,320 and unpolarised light. 323 00:35:44,760 --> 00:35:48,000 But unlike fiddler crabs, part of its body, 324 00:35:48,000 --> 00:35:52,120 like these paddle-shaped scales, reflect polarised light... 325 00:35:53,480 --> 00:35:56,520 ..and may be used to signal to potential mates. 326 00:36:03,640 --> 00:36:08,080 The tail is also highly polarised and used to plug its burrow 327 00:36:08,080 --> 00:36:11,520 and send a message to warn off potential rivals. 328 00:36:17,640 --> 00:36:20,920 And by combining all its visual abilities, 329 00:36:20,920 --> 00:36:25,520 the mantis shrimp has become one of the most skilful of all predators. 330 00:36:37,960 --> 00:36:42,400 It also packs a powerful punch from club-like mouth parts... 331 00:36:46,280 --> 00:36:48,680 ..which it uses with great accuracy. 332 00:36:51,400 --> 00:36:55,680 These clubs deliver the fastest punch in the animal kingdom, 333 00:36:55,680 --> 00:36:59,880 which we recorded slowed down and under controlled conditions. 334 00:37:13,040 --> 00:37:18,440 Whether underwater or on land, colour can be extremely useful. 335 00:37:23,400 --> 00:37:26,800 And the colours an animal develops can sometimes be 336 00:37:26,800 --> 00:37:30,520 influenced by where it lives and what it eats. 337 00:37:39,480 --> 00:37:42,520 The Atacama Desert in South America. 338 00:37:54,360 --> 00:37:58,200 There are six different species of flamingos in the world, 339 00:37:58,200 --> 00:38:01,640 and they all prefer to breed in those most 340 00:38:01,640 --> 00:38:05,880 hostile of environments - salt flats and soda lakes. 341 00:38:11,520 --> 00:38:15,680 We think of flamingos as being characteristically pink, 342 00:38:15,680 --> 00:38:19,280 but their feathers when they first appear are in fact white. 343 00:38:23,760 --> 00:38:26,360 Their colour comes from their food. 344 00:38:29,880 --> 00:38:34,280 The salty waters in which they feed are rich in algae and shrimps, 345 00:38:34,280 --> 00:38:38,400 both of which contain red pigments called carotenoids. 346 00:38:41,600 --> 00:38:44,880 These, over time, accumulate in their feathers and give them 347 00:38:44,880 --> 00:38:45,880 their bright colour. 348 00:39:03,200 --> 00:39:06,440 These youngsters were born last year. 349 00:39:06,440 --> 00:39:09,280 They still have their first greyish-white plumage. 350 00:39:16,000 --> 00:39:18,920 It takes time before the pigments become visible. 351 00:39:25,080 --> 00:39:29,680 Five years will pass before they become as pink as their parents. 352 00:39:38,680 --> 00:39:41,760 But it's not only the juveniles which are white. 353 00:39:47,480 --> 00:39:51,040 This adult female raised a chick last year, 354 00:39:51,040 --> 00:39:54,560 and the effort of doing so has drained her of colour. 355 00:39:57,840 --> 00:40:01,680 She put all her surplus food and energy into producing an egg 356 00:40:01,680 --> 00:40:03,600 and then feeding her chick. 357 00:40:05,960 --> 00:40:09,880 So she will need time to build up the body reserves needed to 358 00:40:09,880 --> 00:40:12,640 regrow pink feathers and breed. 359 00:40:20,840 --> 00:40:24,200 For those that are old enough and physically fit, 360 00:40:24,200 --> 00:40:26,040 it's time to find a mate. 361 00:40:29,960 --> 00:40:33,160 Only the pink birds take part in these courtship dances. 362 00:40:37,640 --> 00:40:41,640 Their colour is an indication that they're fit and strong. 363 00:41:01,000 --> 00:41:03,320 As they march through the water, 364 00:41:03,320 --> 00:41:06,360 each bird tries to stand out from the crowd... 365 00:41:07,520 --> 00:41:11,120 ..and the brightest will be the first to secure a partner. 366 00:41:18,240 --> 00:41:22,600 The white female can play no part in this year's display. 367 00:41:29,640 --> 00:41:32,080 She will need to eat as much as she can 368 00:41:32,080 --> 00:41:34,160 if she is to restore her colour. 369 00:41:37,600 --> 00:41:42,040 Maybe next year she will be able to rejoin the dance. 370 00:41:54,160 --> 00:41:58,040 Flamingos depend on their pink colour to attract a partner 371 00:41:58,040 --> 00:41:59,080 and breed. 372 00:42:02,120 --> 00:42:06,160 But there is one tiny animal in the Central American rainforests 373 00:42:06,160 --> 00:42:08,400 that uses colour not only 374 00:42:08,400 --> 00:42:10,640 to attract, but to repel. 375 00:42:21,240 --> 00:42:24,320 This little frog uses colour as a warning. 376 00:42:25,480 --> 00:42:27,760 Its skin is full of glands 377 00:42:27,760 --> 00:42:30,600 which produce a deadly poison, 378 00:42:30,600 --> 00:42:31,720 so its colour is 379 00:42:31,720 --> 00:42:33,200 a very clear message - 380 00:42:33,200 --> 00:42:35,520 eat me and you'll regret it! 381 00:42:39,280 --> 00:42:43,880 You need a vivid message like this if you are a small, 382 00:42:43,880 --> 00:42:49,240 soft-skinned, bite-sized mouthful living in a dark, dense forest. 383 00:43:02,240 --> 00:43:05,280 The rainforest can be a scary place. 384 00:43:09,960 --> 00:43:12,600 There are hungry animals everywhere. 385 00:43:27,720 --> 00:43:31,120 For many, it's best to keep a low profile. 386 00:43:35,760 --> 00:43:37,920 But this little frog doesn't. 387 00:43:39,800 --> 00:43:43,120 It's a strawberry poison-dart frog, 388 00:43:43,120 --> 00:43:45,720 and it's not much bigger than your fingernail... 389 00:43:46,800 --> 00:43:49,760 ..and yet he is one of the deadliest creatures here. 390 00:43:52,840 --> 00:43:55,400 His bright skin secretes a toxin. 391 00:43:57,800 --> 00:44:01,760 In the mouth of a predator, it can cause respiratory failure, 392 00:44:01,760 --> 00:44:04,000 convulsions and death. 393 00:44:07,760 --> 00:44:12,320 Predators recognise his colour as a sign of danger and avoid him. 394 00:44:19,280 --> 00:44:23,400 Such frogs also live on a group of islands just off Panama 395 00:44:23,400 --> 00:44:25,560 called Bocas del Toro. 396 00:44:27,920 --> 00:44:29,440 Living in isolation, 397 00:44:29,440 --> 00:44:33,440 frogs on each island evolved their own distinctive colours. 398 00:44:36,640 --> 00:44:39,320 There is a different one on each island. 399 00:44:43,040 --> 00:44:45,520 And yet they're all the same species. 400 00:44:51,720 --> 00:44:55,800 They're different because the diet on some islands makes some 401 00:44:55,800 --> 00:44:58,280 more poisonous than others. 402 00:44:58,280 --> 00:45:02,480 And the more poison a frog has, the more brightly coloured it is. 403 00:45:11,520 --> 00:45:15,760 On Solarte Island, a red male is busy calling. 404 00:45:15,760 --> 00:45:23,840 HE CROAKS 405 00:45:25,280 --> 00:45:29,120 This is his patch, and he's looking for a female. 406 00:45:32,720 --> 00:45:34,240 He should be popular. 407 00:45:34,240 --> 00:45:38,440 Females prefer bright, shiny skin, which is a sign of fitness. 408 00:45:43,360 --> 00:45:47,600 His colour is also an indication to other males of his strength. 409 00:45:56,960 --> 00:45:58,360 He spots an intruder. 410 00:45:59,440 --> 00:46:03,040 He's about the same size, but he's a paler colour. 411 00:46:12,840 --> 00:46:15,800 And he doesn't challenge the brighter frog. 412 00:46:22,320 --> 00:46:24,760 But this one is a different matter. 413 00:46:27,800 --> 00:46:29,360 He is a contender. 414 00:46:40,840 --> 00:46:43,600 Nothing for it but to fight it out. 415 00:47:25,520 --> 00:47:28,960 That did it - he won't be back for a while. 416 00:47:37,280 --> 00:47:39,280 And the reward... 417 00:47:39,280 --> 00:47:40,200 ..a new mate. 418 00:47:47,040 --> 00:47:51,640 For these tiny frogs, colour is central to all aspects of their 419 00:47:51,640 --> 00:47:57,400 lives - for protection, to dominate rivals and to find a partner. 420 00:47:59,040 --> 00:48:02,080 For them, life is colour. 421 00:48:12,160 --> 00:48:15,600 When I started working in television in the 1950s, 422 00:48:15,600 --> 00:48:19,640 all broadcasts were in black and white, and conveying animal 423 00:48:19,640 --> 00:48:24,280 colour took a leap of the imagination on the viewer's part. 424 00:48:24,280 --> 00:48:27,480 Well, those are only some of the birds of paradise we brought back, 425 00:48:27,480 --> 00:48:29,920 and there's one more I'd like to show you - 426 00:48:29,920 --> 00:48:32,560 the king bird of paradise. 427 00:48:32,560 --> 00:48:35,880 Its feathers are brilliant red, except for its white underparts. 428 00:48:38,640 --> 00:48:42,520 When colour TV arrived almost 20 years later, we were suddenly 429 00:48:42,520 --> 00:48:46,160 able to show some of the wonderful colours of the natural world. 430 00:48:52,680 --> 00:48:56,680 Since then, electronic cameras have made extraordinary technical 431 00:48:56,680 --> 00:49:01,560 advances into high definition and even ultra-high definition. 432 00:49:03,240 --> 00:49:06,720 But we've always known that there's another world of colour - 433 00:49:06,720 --> 00:49:09,680 one that only some animals can see. 434 00:49:14,200 --> 00:49:17,960 In these programmes, new camera technology has provided 435 00:49:17,960 --> 00:49:21,280 a window into these hitherto invisible worlds... 436 00:49:25,120 --> 00:49:28,600 ..and one of these is that revealed by polarised light. 437 00:49:31,400 --> 00:49:34,920 It plays a crucial role in the lives of many animals, 438 00:49:34,920 --> 00:49:38,960 including these small fiddler crabs in Darwin, Australia. 439 00:49:44,360 --> 00:49:48,120 We worked with a team of scientists to develop a unique 440 00:49:48,120 --> 00:49:52,840 and pioneering camera system to reveal this hidden world. 441 00:49:52,840 --> 00:49:54,240 100% here. 442 00:49:55,640 --> 00:49:58,880 The camera detects areas of polarisation, 443 00:49:58,880 --> 00:50:02,520 such as the light that passes through polarising sunglasses. 444 00:50:02,520 --> 00:50:05,160 Put it to 100% here. 445 00:50:05,160 --> 00:50:08,840 It then combines vertical and horizontal polarisation 446 00:50:08,840 --> 00:50:13,000 to show the contrast between polarised and unpolarised light. 447 00:50:15,160 --> 00:50:19,480 With this new camera, the team hope to find out how fiddler crabs 448 00:50:19,480 --> 00:50:22,440 use polarised light to signal to each other. 449 00:50:24,720 --> 00:50:27,960 But this camera had been developed in sterile, controlled 450 00:50:27,960 --> 00:50:32,000 conditions, and these fiddler crabs live in one of the least sterile 451 00:50:32,000 --> 00:50:36,000 environments on Earth - Australia's tropical mudflats. 452 00:50:38,800 --> 00:50:42,560 Quite a challenge for the cameraman, Mark Lamble. 453 00:50:42,560 --> 00:50:46,800 That mudflat - it's just a really extreme environment to work. 454 00:50:46,800 --> 00:50:51,880 Blazing sun overhead, really high humidity and almost no airflow. 455 00:50:55,360 --> 00:50:57,000 The camera needed to be 456 00:50:57,000 --> 00:51:01,240 half-buried in mud to get a fiddler crab's eye view. 457 00:51:02,880 --> 00:51:05,880 Whether the camera would work here, no-one could be sure. 458 00:51:07,320 --> 00:51:09,160 I'm slightly worried. 459 00:51:09,160 --> 00:51:11,960 Hopefully, we are not going to miss that special moment 460 00:51:11,960 --> 00:51:15,480 as the camera is not going to work, but I think we'll be OK. 461 00:51:15,480 --> 00:51:17,080 Good luck. Thank you. 462 00:51:20,160 --> 00:51:23,560 Once in position, Mark settled down for an uncomfortable wait. 463 00:51:27,680 --> 00:51:30,960 If the crabs detect the slightest movement, 464 00:51:30,960 --> 00:51:33,280 they disappear into their burrows... 465 00:51:35,680 --> 00:51:36,760 ..again... 466 00:51:38,520 --> 00:51:39,480 ..and again. 467 00:51:42,280 --> 00:51:45,720 I have to be really still or they will not come out at all. 468 00:51:46,880 --> 00:51:48,760 I'd love to be able to have an umbrella over me, 469 00:51:48,760 --> 00:51:50,840 so anything higher than me 470 00:51:50,840 --> 00:51:55,920 is just not tolerated by the fiddler crabs, they just won't come up. 471 00:51:55,920 --> 00:52:00,600 But amazingly, the camera survived the heat, the humidity 472 00:52:00,600 --> 00:52:05,000 and the caustic brine, and eventually Mark was able to capture, 473 00:52:05,000 --> 00:52:09,200 for the first time, a fiddler crab's world in polarised light. 474 00:52:12,760 --> 00:52:16,800 Light reflected from the crabs' bodies is unpolarised, 475 00:52:16,800 --> 00:52:17,880 so they look dark. 476 00:52:19,280 --> 00:52:22,120 This makes them stand out against the mudflats, 477 00:52:22,120 --> 00:52:24,720 from which the reflected light is polarised. 478 00:52:27,000 --> 00:52:30,440 They can see things that we can only imagine. 479 00:52:30,440 --> 00:52:33,760 When you look up and you see a bird fly over, it's a white bird against 480 00:52:33,760 --> 00:52:38,160 a white sky whereas, when they look up, it's just this total silhouette 481 00:52:38,160 --> 00:52:42,840 with the polarisation, and they can see birds coming from miles away, 482 00:52:42,840 --> 00:52:46,240 and often I'm filming and they'll all bolt down their holes, 483 00:52:46,240 --> 00:52:48,040 and I'll wonder why they've done it, 484 00:52:48,040 --> 00:52:49,600 and it's just because they've spotted 485 00:52:49,600 --> 00:52:52,320 a bird way earlier than I would have been able to see it. 486 00:52:55,240 --> 00:52:58,960 So polarised light helps the crabs pick out distant potential 487 00:52:58,960 --> 00:53:03,320 mates, rivals and predators more quickly against their bright, 488 00:53:03,320 --> 00:53:07,000 polarised background. And for Victor, 489 00:53:07,000 --> 00:53:10,240 it was the first time he had seen the camera he had developed in 490 00:53:10,240 --> 00:53:15,720 the lab revealing the world in the way these tiny creatures see it. 491 00:53:15,720 --> 00:53:19,280 It's amazing footage you've captured, Mark. It's really amazing. 492 00:53:20,840 --> 00:53:23,840 You really put the system to its limits today. 493 00:53:27,720 --> 00:53:31,360 But there was one even bigger challenge for the camera - 494 00:53:31,360 --> 00:53:33,960 one that lay farther out to sea. 495 00:53:37,080 --> 00:53:40,760 Underwater, only crustaceans, cephalopods 496 00:53:40,760 --> 00:53:45,680 and a few fish are known to be able to see and react to polarised light. 497 00:53:47,000 --> 00:53:50,080 But there is one animal here that exploits this ability 498 00:53:50,080 --> 00:53:55,840 in a really complex way - the peacock mantis shrimp. 499 00:53:55,840 --> 00:53:59,760 It's not only able to detect polarisation, but has patches 500 00:53:59,760 --> 00:54:04,080 on its body that reflect light in a polarised form, 501 00:54:04,080 --> 00:54:07,520 and it uses them to signal to others of their own kind 502 00:54:07,520 --> 00:54:10,080 in ways that we cannot normally see. 503 00:54:12,400 --> 00:54:15,680 Professor Justin Marshall of Queensland University has 504 00:54:15,680 --> 00:54:19,760 adapted the polarising camera to work underwater. 505 00:54:19,760 --> 00:54:21,120 So here we go, Rory. 506 00:54:21,120 --> 00:54:25,600 This is the camera that's going to show us polarisation. 507 00:54:25,600 --> 00:54:28,640 Rory McGuinness, the team's underwater cameraman, 508 00:54:28,640 --> 00:54:31,480 arrives to see the latest version of the camera. 509 00:54:33,120 --> 00:54:35,320 So you've obviously done a lot of work to get 510 00:54:35,320 --> 00:54:37,160 this into an underwater housing? 511 00:54:37,160 --> 00:54:38,280 Yep, that's right. 512 00:54:38,280 --> 00:54:42,120 So you can see in here there's a computer that runs the camera. 513 00:54:42,120 --> 00:54:44,680 There's quite a lot of engineering going on in there. 514 00:54:50,680 --> 00:54:55,680 Taking the camera for its first test underwater was a tense moment. 515 00:54:55,680 --> 00:54:59,080 Computers and salt water don't usually mix well. 516 00:55:07,640 --> 00:55:09,640 Having found a suitable spot, 517 00:55:09,640 --> 00:55:12,720 it was time for the camera's first critical test. 518 00:55:17,600 --> 00:55:19,640 A leak could be disastrous... 519 00:55:24,080 --> 00:55:25,920 ..but all is well. 520 00:55:25,920 --> 00:55:28,160 Now they need a mantis shrimp. 521 00:55:28,160 --> 00:55:31,280 Looks like a promising area, Justin. 522 00:55:31,280 --> 00:55:33,040 It looks perfect, Rory. 523 00:55:33,040 --> 00:55:37,480 So we're looking for a hole with coral around it. 524 00:55:40,320 --> 00:55:44,640 Hey, look! Is that a mantis shrimp hole? 525 00:55:44,640 --> 00:55:47,200 The hole's resident soon appeared. 526 00:55:47,200 --> 00:55:49,800 It was time for the camera to show what it could do. 527 00:55:51,720 --> 00:55:55,800 As the shrimp turns, the polarised camera shows that its tail 528 00:55:55,800 --> 00:56:00,000 has a shimmering fringe - invisible in normal light. 529 00:56:00,000 --> 00:56:03,280 Look at that. That's extraordinary! 530 00:56:03,280 --> 00:56:05,120 Life in polarised light. 531 00:56:06,560 --> 00:56:08,360 And this is the first time... 532 00:56:10,840 --> 00:56:14,840 ..we've been able to do this with this very special camera. 533 00:56:16,920 --> 00:56:20,680 The light on the ocean floor is unpolarised. 534 00:56:20,680 --> 00:56:23,800 So, in complete reverse to the fiddler crabs, 535 00:56:23,800 --> 00:56:26,840 the mantis shrimps use polarisation to stand out 536 00:56:26,840 --> 00:56:29,320 against the unpolarised background. 537 00:56:33,800 --> 00:56:39,080 Special pigments polarise the light reflected from parts of their body, 538 00:56:39,080 --> 00:56:43,560 allowing them to signal to deter intruders and attract mates. 539 00:56:49,240 --> 00:56:53,880 This camera has revealed to us a first glimpse into a world of light 540 00:56:53,880 --> 00:56:57,360 that we're only beginning to be aware of, let alone understand. 541 00:57:06,320 --> 00:57:09,960 In the next episode, the story of Life In Colour 542 00:57:09,960 --> 00:57:13,280 continues where the stakes are even higher 543 00:57:13,280 --> 00:57:15,760 and colour is the key to survival. 544 00:57:17,680 --> 00:57:22,320 We discover how animals use colour to hide from predators 545 00:57:22,320 --> 00:57:24,280 and from their prey.