1 00:00:02,040 --> 00:00:05,440 The natural world is full of extraordinary animals 2 00:00:05,565 --> 00:00:07,600 with amazing life histories. 3 00:00:07,725 --> 00:00:12,200 Yet, certain stories are more intriguing than others. 4 00:00:13,720 --> 00:00:17,240 The mysteries of a butterfly's life cycle, 5 00:00:17,365 --> 00:00:20,680 or the strange biology of the emperor penguin. 6 00:00:20,805 --> 00:00:25,000 Some of these creatures were surrounded by fantastic myths 7 00:00:25,125 --> 00:00:27,600 and misunderstandings. 8 00:00:27,725 --> 00:00:32,400 Others have only recently revealed their secrets. 9 00:00:32,525 --> 00:00:37,160 These are the creatures that stand out from the crowd, 10 00:00:37,285 --> 00:00:41,720 the curiosities that I find particularly fascinating. 11 00:00:51,120 --> 00:00:52,760 In this programme, 12 00:00:52,885 --> 00:00:55,440 I explore the lives of two mothers 13 00:00:55,565 --> 00:00:59,120 who give birth to unusually sized young. 14 00:00:59,245 --> 00:01:01,080 The giant panda, 15 00:01:01,205 --> 00:01:03,040 which, in relation to its size, 16 00:01:03,165 --> 00:01:07,200 produces one of the smallest babies of any mammal. 17 00:01:07,325 --> 00:01:08,640 And, the kiwi, 18 00:01:08,765 --> 00:01:12,440 which lays one of the biggest eggs in the bird world. 19 00:01:13,800 --> 00:01:19,200 Why do pandas and kiwis have babies of such extreme sizes? 20 00:01:26,080 --> 00:01:30,280 Giant pandas are surely one of the most instantly recognisable 21 00:01:30,405 --> 00:01:31,880 of all mammals. 22 00:01:32,005 --> 00:01:33,800 Yet they're also one of the rarest. 23 00:01:33,925 --> 00:01:37,720 Although they once lived over large parts of Central China, 24 00:01:37,845 --> 00:01:41,960 today they're restricted to just six mountain ranges. 25 00:01:51,080 --> 00:01:52,800 Once lowland creatures, 26 00:01:52,925 --> 00:01:56,360 they now live in higher altitudes, in dense forests. 27 00:02:01,520 --> 00:02:05,640 Very little was known about the wild lives of these elusive animals, 28 00:02:05,765 --> 00:02:09,720 and their reproduction remained a mystery for centuries. 29 00:02:12,480 --> 00:02:16,040 The earliest known ancestors of giant pandas 30 00:02:16,165 --> 00:02:18,160 were small forest-dwelling creatures 31 00:02:18,285 --> 00:02:21,600 that existed just over 11 million years ago. 32 00:02:21,725 --> 00:02:26,480 Larger pandas have been around for about 3 million years. 33 00:02:28,200 --> 00:02:29,680 The giant pandas we know today 34 00:02:29,805 --> 00:02:33,640 evolved when bamboo forests were widespread. 35 00:02:33,765 --> 00:02:36,760 With such an easy, reliable food source, 36 00:02:36,885 --> 00:02:39,440 they abandoned their carnivorous ways, 37 00:02:39,565 --> 00:02:41,920 and took to a plant-based diet. 38 00:02:43,200 --> 00:02:46,520 Today, pandas are a huge attraction in our zoos, 39 00:02:46,645 --> 00:02:50,920 but, persuading them to breed and care for their young in captivity, 40 00:02:51,045 --> 00:02:53,800 has been historically very difficult. 41 00:02:53,925 --> 00:02:56,880 Zookeepers were shocked to discover 42 00:02:57,005 --> 00:03:01,400 that a newborn panda baby is one 900th of the parent's body weight. 43 00:03:01,525 --> 00:03:05,080 The smallest of all percentile mammal babies. 44 00:03:06,080 --> 00:03:10,880 But pandas have been a scientific enigma for a very long time. 45 00:03:12,920 --> 00:03:14,640 In 1869, 46 00:03:14,765 --> 00:03:19,040 a French missionary and naturalist called Abbe Armand David 47 00:03:19,165 --> 00:03:21,280 set off on an expedition to China. 48 00:03:22,480 --> 00:03:24,360 He was an expert horticulturist, 49 00:03:24,485 --> 00:03:27,000 and had been commissioned by the Museum of Paris 50 00:03:27,125 --> 00:03:29,000 to bring back plant specimens. 51 00:03:30,200 --> 00:03:32,800 On the 21st of March, while collecting, 52 00:03:32,925 --> 00:03:36,400 he was invited into a local hunter's house for tea and sweets. 53 00:03:36,525 --> 00:03:39,720 He came across a strange, wiry-haired skin, 54 00:03:39,845 --> 00:03:41,360 rather like this one. 55 00:03:43,040 --> 00:03:46,280 He thought it must have come from an unknown species. 56 00:03:46,405 --> 00:03:48,640 So he asked the hunters to bring him 57 00:03:48,765 --> 00:03:51,440 a specimen of this mysterious creature. 58 00:03:51,565 --> 00:03:56,360 After several days, they brought back one that Armand David described 59 00:03:56,485 --> 00:03:59,680 as "a most excellent black and white bear". 60 00:03:59,805 --> 00:04:04,800 Excitedly, he prepared the skin, and then he sent it off to Paris. 61 00:04:06,120 --> 00:04:08,240 Knowing that it might take time to arrive, 62 00:04:08,365 --> 00:04:12,160 he also wrote a letter to Parisian zoologist Milne-Edwards, 63 00:04:12,285 --> 00:04:15,920 urging him to publish a brief description of the animal 64 00:04:16,045 --> 00:04:19,640 for which David proposed the scientific name 65 00:04:19,765 --> 00:04:21,640 of "Ursus Melanoleucus", 66 00:04:21,765 --> 00:04:24,440 literally meaning "black and white bear". 67 00:04:27,000 --> 00:04:31,120 From the very beginning, this new creature seemed odd for a bear. 68 00:04:31,245 --> 00:04:34,720 It had the carnivorous appearance of other bears, 69 00:04:34,845 --> 00:04:38,160 but it's diet was actually almost entirely vegetarian. 70 00:04:39,720 --> 00:04:41,680 It spent up to ten hours a day 71 00:04:41,805 --> 00:04:45,040 feeding on up to 20kg of bamboo. 72 00:04:53,040 --> 00:04:57,080 And unlike other bears, the panda did not hibernate, 73 00:04:57,205 --> 00:04:59,280 and its babies proved to be far smaller 74 00:04:59,405 --> 00:05:01,280 than those of any other bear. 75 00:05:03,440 --> 00:05:05,800 In fact, the panda was so different 76 00:05:05,925 --> 00:05:09,240 that some doubted that it was a bear at all. 77 00:05:12,240 --> 00:05:16,960 A creature called a "red panda" had been discovered some time before, 78 00:05:17,085 --> 00:05:18,960 and it had striking similarities 79 00:05:19,085 --> 00:05:21,720 to Armand David's new black and white bear. 80 00:05:24,640 --> 00:05:27,320 It, too, fed mainly on plant matter, 81 00:05:27,445 --> 00:05:29,360 about two-thirds of which was bamboo. 82 00:05:31,760 --> 00:05:35,360 But this creature was classified as a relative of weasels, 83 00:05:35,485 --> 00:05:38,680 skunks and raccoons, not bears. 84 00:05:38,805 --> 00:05:43,040 Perhaps the giant panda was not a bear after all. 85 00:05:43,165 --> 00:05:46,440 This could explain why its young was so small, 86 00:05:46,565 --> 00:05:48,320 compared to most other bears. 87 00:05:51,400 --> 00:05:53,680 Milne-Edwards, the Parisian biologist 88 00:05:53,805 --> 00:05:57,160 who received the very first giant panda skin and bones, 89 00:05:57,285 --> 00:06:00,200 compared them to his specimens of red panda. 90 00:06:01,480 --> 00:06:05,480 He believed that the skull structure and the teeth were very similar. 91 00:06:05,605 --> 00:06:09,640 This is the small red panda, and this is the giant panda. 92 00:06:10,600 --> 00:06:15,120 He decided it was a new creature, which deserved a new name, 93 00:06:15,245 --> 00:06:19,800 so he called it "Ailuropoda", meaning "panda foot". 94 00:06:19,925 --> 00:06:23,560 Thus it became known as a panda, and not a bear. 95 00:06:25,680 --> 00:06:29,920 Debate and confusion continued over the panda's identification 96 00:06:30,045 --> 00:06:31,640 for nearly 100 years. 97 00:06:32,760 --> 00:06:36,160 Few people had ever seen more than a fleeting glimpse of one, 98 00:06:36,285 --> 00:06:38,680 and their wild behaviour remained a mystery. 99 00:06:40,080 --> 00:06:41,880 Then, in the 1920s, 100 00:06:42,005 --> 00:06:45,840 exploration became very popular amongst the wealthy. 101 00:06:45,965 --> 00:06:50,480 And the race was on for the first foreigner to hunt and kill a panda. 102 00:06:52,640 --> 00:06:57,240 It's said that Theodore Roosevelt Jr and Kermit Roosevelt 103 00:06:57,365 --> 00:07:00,520 were the first Westerners to shoot a panda. 104 00:07:00,645 --> 00:07:04,880 They persuaded the Field Museum in Chicago to foot the bill 105 00:07:05,005 --> 00:07:06,520 for an expedition, 106 00:07:06,645 --> 00:07:10,560 and were secretive about the "golden fleece" that they were hunting. 107 00:07:10,685 --> 00:07:15,120 After six days of tracking in the same area where Armand David 108 00:07:15,245 --> 00:07:18,040 had first found his panda, they saw nothing. 109 00:07:18,165 --> 00:07:20,360 But after moving further south, 110 00:07:20,485 --> 00:07:23,680 they had a dramatic encounter with a panda that they followed 111 00:07:23,805 --> 00:07:25,960 and shot dead. 112 00:07:27,440 --> 00:07:31,160 Sadly, then, the driving force to collect giant pandas 113 00:07:31,285 --> 00:07:35,360 was money and fame, not biological revelation. 114 00:07:36,600 --> 00:07:40,120 The only way to learn anything more about the giant panda 115 00:07:40,245 --> 00:07:43,680 was to watch one in the wild, or to catch one alive. 116 00:07:45,160 --> 00:07:49,200 In 1936, a baby panda was captured alive. 117 00:07:49,325 --> 00:07:53,320 Named Su Lin, she was the first to be brought into captivity, 118 00:07:53,445 --> 00:07:55,560 but sadly died soon after. 119 00:07:56,960 --> 00:07:59,000 A craze for captive pandas followed. 120 00:08:00,200 --> 00:08:03,960 And in the late 1950s, one arrived in Britain. 121 00:08:04,085 --> 00:08:05,920 This particular individual 122 00:08:06,045 --> 00:08:08,760 would help us to appreciate the complexities 123 00:08:08,885 --> 00:08:10,760 of the giant panda's biology. 124 00:08:12,800 --> 00:08:17,640 Perhaps the most famous and popular of all giant pandas was Chi-Chi, 125 00:08:17,765 --> 00:08:21,320 who came to London Zoo in September 1958. 126 00:08:22,360 --> 00:08:25,120 She was actually on her way to the United States, 127 00:08:25,245 --> 00:08:27,640 but the US Customs refused to admit her 128 00:08:27,765 --> 00:08:30,120 on the grounds that she was a communist, 129 00:08:30,245 --> 00:08:33,440 or, at any rate, came from a communist country. 130 00:08:33,565 --> 00:08:36,960 So, London Zoo was able to buy her for £12,000, 131 00:08:37,085 --> 00:08:40,080 and she was very quickly extremely popular. 132 00:08:41,200 --> 00:08:45,600 Desmond Morris, who was in charge of London Zoo's mammals at the time, 133 00:08:45,725 --> 00:08:47,920 decided, however, that she was alone 134 00:08:48,045 --> 00:08:51,240 and she really ought to be allowed to breed. 135 00:08:51,365 --> 00:08:52,920 Don't you want to go to Moscow? 136 00:08:53,045 --> 00:08:55,680 PANDA SQUEAKS 137 00:08:58,000 --> 00:09:02,680 Here, at last, was a chance to learn more about panda reproduction. 138 00:09:02,805 --> 00:09:05,760 Desmond Morris travelled to Russia with Chi-Chi 139 00:09:05,885 --> 00:09:10,280 to introduce her to a potential mate, a male panda called An-An. 140 00:09:10,405 --> 00:09:14,800 But when they were introduced, all did not go to plan. 141 00:09:14,925 --> 00:09:18,520 Chi-Chi was in no mood to breed, and was sent back home. 142 00:09:23,240 --> 00:09:26,680 Clearly, panda mating was not a simple affair, 143 00:09:26,805 --> 00:09:29,360 and it was a rare sight in the wild, too. 144 00:09:29,485 --> 00:09:34,200 Now we know that successful mating needs very precise timing. 145 00:09:34,325 --> 00:09:37,200 Female pandas live a solitary life, 146 00:09:37,325 --> 00:09:41,040 and are only ready to mate for just one or two days a year. 147 00:09:41,165 --> 00:09:44,920 Even then, there is a window of 12 to 24 hours. 148 00:09:45,045 --> 00:09:48,720 It's little wonder that Chi-Chi did not breed. 149 00:09:49,800 --> 00:09:52,560 Males are attracted to the female's scent, 150 00:09:52,685 --> 00:09:55,320 and will guard them until they're ready to mate. 151 00:09:56,480 --> 00:09:59,160 A female in season is a rare thing, 152 00:09:59,285 --> 00:10:02,480 and competition to mate is worth fighting for. 153 00:10:02,605 --> 00:10:06,520 GROWLING, BARKING SOUND 154 00:10:21,400 --> 00:10:25,400 The panda was gaining a reputation for having unusual and difficult 155 00:10:25,525 --> 00:10:30,080 breeding habits, and its peculiar diet seemed to be responsible. 156 00:10:36,160 --> 00:10:41,280 In the 1960s, biologists took a fresh look at the giant panda. 157 00:10:43,360 --> 00:10:47,080 This time, they studied the panda's digestive system, 158 00:10:47,205 --> 00:10:51,120 and discovered that it was exactly like that of a carnivorous bear. 159 00:10:52,680 --> 00:10:55,120 So, the giant panda was reclassified, 160 00:10:55,245 --> 00:11:00,200 and changed from being a relative of the red panda, to being a true bear. 161 00:11:02,120 --> 00:11:06,080 This also revealed that the giant panda gut was unsuited 162 00:11:06,205 --> 00:11:07,840 to its plant-based diet, 163 00:11:07,965 --> 00:11:11,480 and that this oddity might affect its metabolism and breeding. 164 00:11:11,605 --> 00:11:13,080 But how? 165 00:11:15,600 --> 00:11:17,600 Female bears feed on rich food 166 00:11:17,725 --> 00:11:21,520 to build up fat reserves for motherhood and hibernation. 167 00:11:21,645 --> 00:11:25,080 They then give birth to up to four babies, 168 00:11:25,205 --> 00:11:28,040 and produce enough milk to feed all of them. 169 00:11:28,165 --> 00:11:33,000 The well-grown cubs emerge from the den in early spring. 170 00:11:33,125 --> 00:11:36,920 Panda reproduction has significant differences. 171 00:11:37,045 --> 00:11:39,800 They don't have enough fat reserves to hibernate, 172 00:11:39,925 --> 00:11:43,520 and usually produce only one small baby at a time. 173 00:11:43,645 --> 00:11:45,520 Their poor vegetarian diet 174 00:11:45,645 --> 00:11:48,240 seems to have had an impact on their breeding. 175 00:11:49,840 --> 00:11:53,080 Bamboo presents a lot of problems as a food. 176 00:11:53,205 --> 00:11:56,080 To start with, it's very low in energy. 177 00:11:56,205 --> 00:11:59,240 Secondly, the panda has to sit upright 178 00:11:59,365 --> 00:12:03,480 in order to release its front paws, in order to handle the bamboo. 179 00:12:03,605 --> 00:12:07,680 On top of that, the panda's gut is very short, 180 00:12:07,805 --> 00:12:09,760 like that of a carnivore, 181 00:12:09,885 --> 00:12:12,320 so that the food, when it's eaten, 182 00:12:12,445 --> 00:12:15,280 passes through its body very quickly. 183 00:12:15,405 --> 00:12:17,920 As a consequence of all those difficulties, 184 00:12:18,045 --> 00:12:23,000 the panda only manages to extract about 20% of the little energy 185 00:12:23,125 --> 00:12:24,640 that bamboo does contain. 186 00:12:26,240 --> 00:12:30,440 So, the Panda's ancestors switched from being meat eaters 187 00:12:30,565 --> 00:12:33,640 to plant eaters, and this compromised their digestive systems 188 00:12:33,765 --> 00:12:37,320 and greatly affected their metabolism. 189 00:12:37,445 --> 00:12:39,720 They became slow-moving, 190 00:12:39,845 --> 00:12:43,360 and their breeding changed to cope with such a low-energy diet. 191 00:12:46,320 --> 00:12:48,240 In the late 1960s, 192 00:12:48,365 --> 00:12:52,520 efforts to understand panda reproduction became more crucial 193 00:12:52,645 --> 00:12:54,880 as their numbers in the wild plummeted. 194 00:12:55,005 --> 00:12:58,120 The Worldwide Fund for Nature was formed, 195 00:12:58,245 --> 00:13:02,080 and their famous logo was a panda based on Chi-Chi. 196 00:13:05,400 --> 00:13:09,880 The Chinese built a state-of-the-art reserve in Wolong, 197 00:13:10,005 --> 00:13:13,520 leading to a new era of great progress in panda breeding. 198 00:13:16,440 --> 00:13:20,280 Small babies weighing an average of just 100g 199 00:13:20,405 --> 00:13:24,600 are now regularly born in captivity, and are fed on milk for many months. 200 00:13:27,520 --> 00:13:29,280 On a poor diet of bamboo, 201 00:13:29,405 --> 00:13:32,840 pandas are unable to grow bigger babies in the womb, 202 00:13:32,965 --> 00:13:37,040 so they give birth to small young, and use their limited nutrition 203 00:13:37,165 --> 00:13:39,880 to produce food for them after birth. 204 00:13:41,240 --> 00:13:42,600 As with all mammals, 205 00:13:42,725 --> 00:13:45,240 milk is essential to the baby's development, 206 00:13:45,365 --> 00:13:49,200 and ensures even the tiniest babies grow up to be giants. 207 00:13:52,560 --> 00:13:56,600 So, the giant panda is not a racoon, it's a bear. 208 00:13:56,725 --> 00:14:01,280 A bear that spends nearly all its time eating vegetation, 209 00:14:01,405 --> 00:14:03,600 and that's nearly always bamboo. 210 00:14:03,725 --> 00:14:07,200 Which, although it can occasionally produce twins, 211 00:14:07,325 --> 00:14:11,000 normally gives birth to just one baby at a time. 212 00:14:11,125 --> 00:14:12,920 And that a very small one. 213 00:14:14,520 --> 00:14:17,440 But those are the consequences if you are a bear 214 00:14:17,565 --> 00:14:21,640 that has become adapted to living on a very low-energy diet. 215 00:14:23,880 --> 00:14:26,920 The panda's tiny baby is an oddity, 216 00:14:27,045 --> 00:14:30,440 but the only solution for a bamboo-eating bear. 217 00:14:32,000 --> 00:14:33,480 In New Zealand, 218 00:14:33,605 --> 00:14:38,080 there's a very different creature that has just as curious a story. 219 00:14:45,640 --> 00:14:48,840 The kiwi is one of the strangest of birds. 220 00:14:48,965 --> 00:14:51,440 WARBLING 221 00:14:51,565 --> 00:14:55,640 It sleeps underground, and usually only comes out at night. 222 00:14:57,760 --> 00:15:02,440 It can't fly, and its brown feathers resemble a thick coat of fur. 223 00:15:04,520 --> 00:15:08,880 Its small eyes are virtually useless and it finds its food 224 00:15:09,005 --> 00:15:10,680 with its sensitive beak. 225 00:15:10,805 --> 00:15:15,560 It's a peculiar lifestyle, more like that of a nocturnal mammal. 226 00:15:16,760 --> 00:15:21,000 But most remarkable of all, it lays the biggest egg of any bird 227 00:15:21,125 --> 00:15:23,240 in proportion to its body. 228 00:15:25,920 --> 00:15:28,800 A kiwi is roughly the size of a chicken. 229 00:15:28,925 --> 00:15:30,480 But its egg... 230 00:15:30,605 --> 00:15:33,680 ..is more than seven times as large as a chicken's egg. 231 00:15:33,805 --> 00:15:36,200 And it can weigh half a kilo. 232 00:15:36,325 --> 00:15:39,160 It's hard to imagine how this huge egg 233 00:15:39,285 --> 00:15:42,280 could fit into a kiwi's small body. 234 00:15:42,405 --> 00:15:43,680 And, yet, it does. 235 00:15:44,880 --> 00:15:46,320 Just before the egg is laid, 236 00:15:46,445 --> 00:15:48,840 it takes up so much room inside the female 237 00:15:48,965 --> 00:15:50,920 that her belly almost touches the ground. 238 00:15:51,045 --> 00:15:54,680 And when she lays it, it's equivalent, in terms of weight, 239 00:15:54,805 --> 00:15:58,480 to a human mother giving birth to a four-year-old child. 240 00:16:02,680 --> 00:16:06,920 Most birds only take around a day to produce an egg. 241 00:16:07,045 --> 00:16:11,800 But because the kiwi's is so large, it takes almost ten days. 242 00:16:15,920 --> 00:16:20,240 The female's inner organs become so compressed, she can't feed. 243 00:16:24,080 --> 00:16:27,880 Expelling the monster egg is also a huge effort. 244 00:16:37,840 --> 00:16:40,760 Why is the kiwi such a curiosity? 245 00:16:40,885 --> 00:16:43,960 And why does it lay such a gigantic egg? 246 00:16:47,040 --> 00:16:50,280 The kiwi didn't come to the attention of Europeans 247 00:16:50,405 --> 00:16:54,920 until about 200 years ago, when a dried specimen, much like this one, 248 00:16:55,045 --> 00:16:58,080 arrived in England on a merchant vessel. 249 00:16:58,205 --> 00:17:00,080 It puzzled those who saw it. 250 00:17:00,205 --> 00:17:03,320 It was clearly a bird, but it had no wings. 251 00:17:04,360 --> 00:17:09,360 Its feathers were soft and hairy, more like mammalian fur. 252 00:17:09,485 --> 00:17:11,720 And it had these strange, long whiskers 253 00:17:11,845 --> 00:17:13,440 around the base of the beak. 254 00:17:13,565 --> 00:17:16,080 The first specimen was examined and described by a naturalist 255 00:17:16,205 --> 00:17:19,640 at the British Museum, a man called George Shaw, 256 00:17:19,765 --> 00:17:24,000 who gave it the scientific name Apteryx, which, in Greek, 257 00:17:24,125 --> 00:17:26,600 means "wingless creature". 258 00:17:26,725 --> 00:17:30,320 Shaw studied the skin, together with his colleague John Latham, 259 00:17:30,445 --> 00:17:34,240 but the two men disagreed as to what kind of bird it could be. 260 00:17:34,365 --> 00:17:36,600 They knew it had come from New Zealand, 261 00:17:36,725 --> 00:17:40,600 and Shaw thought it was probably related to the ratites, 262 00:17:40,725 --> 00:17:44,320 a group of primitive flightless birds that includes the ostrich. 263 00:17:45,520 --> 00:17:47,040 Latham, on the other hand, 264 00:17:47,165 --> 00:17:50,000 was convinced that it was a kind of penguin. 265 00:17:51,520 --> 00:17:54,320 When Shaw published his description in 1813, 266 00:17:54,445 --> 00:17:58,280 it was accompanied by an artist's impression of the living bird. 267 00:17:58,405 --> 00:17:59,480 This is it. 268 00:17:59,605 --> 00:18:03,840 Clearly, the artist must have been swayed by Latham's argument, 269 00:18:03,965 --> 00:18:05,880 rather than Shaw's. 270 00:18:06,005 --> 00:18:08,920 He shows the kiwi standing bolt upright and very tall, 271 00:18:09,045 --> 00:18:10,240 much like a penguin. 272 00:18:11,520 --> 00:18:15,000 And so the kiwi was introduced to the scientific world. 273 00:18:17,800 --> 00:18:22,560 Shaw's kiwi continued to provoke debate long after his death. 274 00:18:22,685 --> 00:18:26,320 The most eminent zoologists of the time disagreed 275 00:18:26,445 --> 00:18:28,880 over the nature of the strange creature 276 00:18:29,005 --> 00:18:31,680 and, indeed, whether it actually existed. 277 00:18:34,520 --> 00:18:38,200 It's not surprising that many wondered if the kiwi was a hoax. 278 00:18:38,325 --> 00:18:41,720 It was a time when travellers were bringing back all kinds of strange 279 00:18:41,845 --> 00:18:45,440 creatures from far-flung places, and many were frauds, 280 00:18:45,565 --> 00:18:48,880 put together from parts of different animals. 281 00:18:49,920 --> 00:18:51,720 Almost 20 years later, 282 00:18:51,845 --> 00:18:54,960 and with only one specimen on which to make a judgment, 283 00:18:55,085 --> 00:19:00,960 the Zoological Society of London made an appeal for more kiwi skins. 284 00:19:01,085 --> 00:19:04,960 So, other specimens finally began to arrive in Britain. 285 00:19:07,480 --> 00:19:10,560 European naturalists may have been mystified by the kiwi, 286 00:19:10,685 --> 00:19:12,680 but the Maori people of New Zealand 287 00:19:12,805 --> 00:19:16,880 had admired and respected the bird for a very long time. 288 00:19:18,160 --> 00:19:20,160 According to Maori legend, 289 00:19:20,285 --> 00:19:23,240 the kiwi lost its wings at the request of Tane, 290 00:19:23,365 --> 00:19:24,760 the god of the forest. 291 00:19:24,885 --> 00:19:30,000 Tane asked all birds to go down to live on the forest floor 292 00:19:30,125 --> 00:19:32,920 and feed on the insects that were killing the trees. 293 00:19:33,045 --> 00:19:38,400 But only the kiwi agreed, and gave up his wings and beautiful feathers. 294 00:19:39,760 --> 00:19:43,360 So, the kiwi has always been sacred to the Maori. 295 00:19:48,760 --> 00:19:52,400 Back in Europe, others now joined in the debate. 296 00:19:53,640 --> 00:19:55,160 Professor Richard Owen, 297 00:19:55,285 --> 00:19:58,120 the most powerful British zoologist of the time, 298 00:19:58,245 --> 00:20:00,840 studied the anatomy of the kiwi in detail. 299 00:20:03,960 --> 00:20:07,120 Comparing its features to those of other birds, 300 00:20:07,245 --> 00:20:10,440 he concluded that it was most closely related 301 00:20:10,565 --> 00:20:13,280 to that group of flightless birds called the ratites. 302 00:20:20,040 --> 00:20:23,720 The ratites include the largest birds in the world - 303 00:20:23,845 --> 00:20:27,160 the emu, the South American rhea, 304 00:20:27,285 --> 00:20:30,080 the cassowary, and the ostrich. 305 00:20:30,205 --> 00:20:33,720 All of them stand nearly as tall as a human being. 306 00:20:36,280 --> 00:20:39,920 So, could the kiwi's large egg have anything to do 307 00:20:40,045 --> 00:20:43,520 with its possible relationship to these larger birds? 308 00:20:43,645 --> 00:20:47,720 To answer that, we need to look at its close relatives. 309 00:20:52,920 --> 00:20:55,640 The emu lives nearby in Australia. 310 00:20:57,040 --> 00:21:00,000 It has remnants of wings, but it can't fly. 311 00:21:01,280 --> 00:21:03,920 And its feathers are similar to those of the kiwi, 312 00:21:04,045 --> 00:21:05,640 hairy and plume-like. 313 00:21:07,320 --> 00:21:10,480 They simply serve to protect the bird, and keep it warm. 314 00:21:13,120 --> 00:21:18,040 So, how similar are the emu and the kiwi when it comes to their eggs? 315 00:21:19,640 --> 00:21:22,040 This is the egg of a kiwi. 316 00:21:22,165 --> 00:21:25,120 And this is the egg of an emu. 317 00:21:25,245 --> 00:21:27,480 More or less the same size. 318 00:21:27,605 --> 00:21:30,320 And, yet, the kiwi is the size of a chicken, 319 00:21:30,445 --> 00:21:33,480 but an emu is almost as tall as I am. 320 00:21:33,605 --> 00:21:37,640 Why should such a big egg come from such a small bird? 321 00:21:37,765 --> 00:21:39,480 Well, for a long time, 322 00:21:39,605 --> 00:21:44,000 it was argued that that was because the ancestors of the kiwi 323 00:21:44,125 --> 00:21:47,880 were once as big as the emu and, over time, 324 00:21:48,005 --> 00:21:51,480 they got smaller, but the egg remained the same size. 325 00:21:51,605 --> 00:21:55,760 And the originator of that theory was, in fact, Richard Owen himself. 326 00:21:58,960 --> 00:22:05,240 In 1839, Owen acquired the fragment of a strange bone from New Zealand. 327 00:22:07,000 --> 00:22:11,320 After studying it closely, he suggested it came from a gigantic, 328 00:22:11,445 --> 00:22:14,720 flightless bird that was probably extinct. 329 00:22:15,760 --> 00:22:19,920 From this meagre evidence, he reconstructed the entire animal, 330 00:22:20,045 --> 00:22:23,000 a giant moa. 331 00:22:23,125 --> 00:22:26,560 Owen was ridiculed by other scientists at the time, 332 00:22:26,685 --> 00:22:30,520 who considered such a deduction on one bone outrageous. 333 00:22:30,645 --> 00:22:33,720 But in due course, other moa birds were found, 334 00:22:33,845 --> 00:22:35,720 and he was proved to be correct. 335 00:22:37,320 --> 00:22:40,680 Owen's discoveries seemed to confirm the idea 336 00:22:40,805 --> 00:22:44,440 that the kiwi could have evolved from a big bird like the moa, 337 00:22:44,565 --> 00:22:48,560 and that maybe its egg was a relic from a giant ancestor. 338 00:22:51,960 --> 00:22:54,880 Large, flightless birds first appeared 339 00:22:55,005 --> 00:22:57,120 when the dinosaurs became extinct. 340 00:22:58,520 --> 00:23:01,440 This is a southern cassowary. 341 00:23:01,565 --> 00:23:05,480 It's a native of northern Australia and New Guinea. 342 00:23:05,605 --> 00:23:07,520 And the males, like this one, 343 00:23:07,645 --> 00:23:11,000 are extremely territorial and, therefore, dangerous. 344 00:23:11,125 --> 00:23:14,280 They will attack you, as I know to my cost. 345 00:23:14,405 --> 00:23:16,480 So, I'm not going to get in there with him. 346 00:23:16,605 --> 00:23:19,160 Instead, I'll see if I can tempt him 347 00:23:19,285 --> 00:23:22,440 with a few grapes, which are one of his favourite foods. 348 00:23:24,280 --> 00:23:27,800 Like the kiwi, the cassowary evolved 349 00:23:27,925 --> 00:23:31,840 in an area where the adult birds have no ground predators. 350 00:23:31,965 --> 00:23:34,760 As a consequence, they don't fly. 351 00:23:35,880 --> 00:23:38,800 Flying is a very energy-demanding business. 352 00:23:38,925 --> 00:23:42,600 If birds don't need to fly, birds don't fly. 353 00:23:46,840 --> 00:23:50,120 Until recently, it was thought that all the ratites 354 00:23:50,245 --> 00:23:52,320 had one common flightless ancestor. 355 00:23:54,040 --> 00:23:57,880 This seemed possible because the places where they live today 356 00:23:58,005 --> 00:24:01,440 were once part of a supercontinent called Gondwanaland. 357 00:24:02,880 --> 00:24:07,200 When this continent split up around 150 million years ago, 358 00:24:07,325 --> 00:24:08,960 the fragments drifted apart. 359 00:24:10,600 --> 00:24:14,640 Each one might independently have evolved its own flightless species, 360 00:24:14,765 --> 00:24:16,280 including New Zealand. 361 00:24:20,000 --> 00:24:22,720 When Owen came to examine the skeleton of a kiwi, 362 00:24:22,845 --> 00:24:26,000 he noticed something very strange about the skull. 363 00:24:27,080 --> 00:24:30,640 Most bird skulls have two little tiny holes there 364 00:24:30,765 --> 00:24:33,320 at the base of the beak, which accommodates the nostrils, 365 00:24:33,445 --> 00:24:34,760 through which they smell. 366 00:24:34,885 --> 00:24:38,440 But there are no such things here on the kiwi skull. 367 00:24:38,565 --> 00:24:43,960 Instead, the nostrils are right at the tip of the beak. 368 00:24:45,120 --> 00:24:49,360 Not only that, but these big spaces on either side the skull, 369 00:24:49,485 --> 00:24:53,200 which in most birds hold the big eye, 370 00:24:53,325 --> 00:24:58,080 are, in fact, filled by the olfactory organ, the smelling organ. 371 00:24:59,640 --> 00:25:03,640 And Owen deduced from those two facts that this, therefore, 372 00:25:03,765 --> 00:25:07,560 must belong to a bird that was nocturnal. 373 00:25:07,685 --> 00:25:08,960 And he was quite right. 374 00:25:13,040 --> 00:25:15,840 The kiwi is mostly active at night, 375 00:25:15,965 --> 00:25:19,680 and uses both touch and smell to find its food. 376 00:25:22,320 --> 00:25:26,000 The long whiskers allow it to feel its way in the dark, 377 00:25:26,125 --> 00:25:28,280 and special sensory cells in the beak 378 00:25:28,405 --> 00:25:30,480 detect the movement of prey underground. 379 00:25:32,120 --> 00:25:35,840 But why did the kiwi choose this unusual lifestyle? 380 00:25:37,760 --> 00:25:41,360 It's possible that the moas had already taken the role 381 00:25:41,485 --> 00:25:43,440 of giant plant eaters during the day, 382 00:25:43,565 --> 00:25:47,320 so the kiwi may have shrunk down to feed on small insects at night. 383 00:25:49,720 --> 00:25:52,760 Owen had shed light on both the moa and kiwi, 384 00:25:52,885 --> 00:25:55,800 but he was wrong about their true relationship. 385 00:25:57,360 --> 00:26:01,680 Evidence from DNA has now revealed that the kiwi is, in fact, 386 00:26:01,805 --> 00:26:05,720 more closely related to flightless birds of Africa and Australia. 387 00:26:06,720 --> 00:26:10,920 This means that the moa and the kiwi had different ancestors, 388 00:26:11,045 --> 00:26:14,840 and flightlessness must have evolved in New Zealand 389 00:26:14,965 --> 00:26:16,720 on two separate occasions. 390 00:26:19,760 --> 00:26:21,960 It's an extraordinary thought. 391 00:26:22,085 --> 00:26:25,120 But another recent finding supports the idea. 392 00:26:26,680 --> 00:26:30,760 Genetic techniques have shown that the closest relative of the ratites 393 00:26:30,885 --> 00:26:35,360 is, in fact, a small flying bird, the tinamou. 394 00:26:37,240 --> 00:26:40,360 Tinamous are partridge-like birds from South America 395 00:26:40,485 --> 00:26:42,920 that spend much of their time on the ground, 396 00:26:43,045 --> 00:26:45,000 but they can fly perfectly well. 397 00:26:46,280 --> 00:26:49,880 So, it seems that birds like this may have flapped their way 398 00:26:50,005 --> 00:26:54,040 between the continents, giving rise to the different ratites, 399 00:26:54,165 --> 00:26:55,440 including the kiwi. 400 00:27:01,800 --> 00:27:06,080 We've unravelled much of the mystery around the kiwi's curious lifestyle, 401 00:27:06,205 --> 00:27:08,480 but one question remains. 402 00:27:08,605 --> 00:27:12,080 What could be the reason for its huge egg? 403 00:27:14,040 --> 00:27:18,240 Some think that the large egg may give the kiwi a competitive edge, 404 00:27:18,365 --> 00:27:22,480 by allowing it to hatch a chick that is already very well developed. 405 00:27:23,880 --> 00:27:25,960 It's like a miniature adult, 406 00:27:26,085 --> 00:27:28,840 and the large yolk sac provides nourishment 407 00:27:28,965 --> 00:27:31,560 until it becomes fully independent. 408 00:27:37,360 --> 00:27:41,560 So, it seems that the kiwi's gigantic egg may have evolved 409 00:27:41,685 --> 00:27:43,520 to suit its lifestyle and habitat. 410 00:27:43,645 --> 00:27:47,080 Most birds have to lay their eggs as soon as possible 411 00:27:47,205 --> 00:27:50,040 to avoid being weighed down when flying. 412 00:27:50,165 --> 00:27:54,640 But the flightless kiwi has no such problem, and can, therefore, 413 00:27:54,765 --> 00:27:58,680 keep the heavy egg in its body for longer, and let it grow bigger. 414 00:27:59,800 --> 00:28:04,080 And in an environment with few predators, it may make sense to, 415 00:28:04,205 --> 00:28:08,640 as it were, put all your eggs in one basket and raise a single chick 416 00:28:08,765 --> 00:28:10,440 that is big and strong, 417 00:28:10,565 --> 00:28:13,080 and therefore has the better chance of survival. 418 00:28:14,320 --> 00:28:18,160 The kiwi and the panda both produce young that stand out 419 00:28:18,285 --> 00:28:19,920 because of their size, 420 00:28:20,045 --> 00:28:25,520 but are a perfect fit for the life choices of these curious creatures.