1 00:00:57,700 --> 00:01:03,700 Blue water covers most of our planet, but in it are set tiny specks of land, 2 00:01:03,870 --> 00:01:08,590 some the tips of volcanoes, some mere rings of coral. 3 00:01:09,000 --> 00:01:11,210 They're miniature enclosed worlds 4 00:01:11,420 --> 00:01:18,430 where animals and plants become transformed into new species with extraordinary speed. 5 00:01:46,080 --> 00:01:51,420 If you wanted to pick a really remote desert island cut off from the rest of the world, 6 00:01:51,630 --> 00:01:53,340 you might well choose this one. 7 00:01:53,840 --> 00:01:56,720 This is Aldabra in the Indian Ocean. 8 00:01:56,970 --> 00:02:02,970 The nearest land in that direction is the coast of Africa, about 250 miles away. 9 00:02:03,850 --> 00:02:07,100 Over there, about the same distance, is Madagascar, 10 00:02:07,350 --> 00:02:11,440 and if you sailed in that direction, you wouldn't hit much 11 00:02:11,610 --> 00:02:15,740 until you got to the coast of Australia 4,000 miles away. 12 00:02:16,030 --> 00:02:20,620 The island is the tip of an extinct submarine volcano 13 00:02:20,820 --> 00:02:27,000 that rises 15,000 feet from the bottom of the Indian Ocean and is capped with coral rock. 14 00:02:27,580 --> 00:02:34,760 When it finally rose above the surface of the sea about 50,000 years ago, it was lifeless, 15 00:02:35,090 --> 00:02:39,550 but now, a mere 50,000 years later, well, just look. 16 00:02:42,600 --> 00:02:47,310 Frigate birds, thousands of them, circle above one end of the island. 17 00:02:47,560 --> 00:02:53,770 They've come from all over the Indian Ocean, even from India itself 2,000 miles away, 18 00:02:53,940 --> 00:02:57,570 to nest on this particular island in the mangroves. 19 00:03:05,240 --> 00:03:08,250 The white-headed birds among them are immatures, 20 00:03:08,500 --> 00:03:12,080 and there are two different species of them, one bigger than the other. 21 00:03:15,050 --> 00:03:20,380 The males inflate their scarlet throat pouches to show that the site is taken, 22 00:03:20,630 --> 00:03:22,260 and to attract the female. 23 00:03:24,930 --> 00:03:29,980 When she arrives, he persuades her to stay with ecstatic shakes of his head. 24 00:03:47,330 --> 00:03:49,250 Red-footed boobies are here, too. 25 00:03:49,580 --> 00:03:53,460 They're great travellers, and their chicks, which are already fledging, 26 00:03:53,630 --> 00:03:58,300 may well be fishing 3,000 or 4,000 miles away within a year. 27 00:03:59,590 --> 00:04:03,510 Noddies nest not on Aldabra but on a neighbouring atoll, 28 00:04:03,680 --> 00:04:07,430 building platforms of seaweed in the Pisonia trees, 29 00:04:07,640 --> 00:04:14,020 and beneath, on the open coral sand, two million sooty terns lay their eggs. 30 00:04:16,820 --> 00:04:21,200 Their vast numbers are an indication of the richness of the surrounding sea. 31 00:04:21,780 --> 00:04:25,620 Every day, the birds take from it many tons of small fish, 32 00:04:25,870 --> 00:04:28,790 little squid and other marine creatures. 33 00:04:37,000 --> 00:04:39,880 The atoll itself provides no food for them. 34 00:04:40,170 --> 00:04:42,380 All a pair of sooty terns seek from it 35 00:04:42,550 --> 00:04:47,600 are a few square inches of dry land on which to place their single egg, 36 00:04:47,760 --> 00:04:52,980 and an absence of cats, rats and all other egg-stealers and chick-eaters 37 00:04:53,190 --> 00:04:56,230 that plague nesting sites on the mainland. 38 00:04:57,480 --> 00:05:00,320 Such security is important to these terns, 39 00:05:00,530 --> 00:05:05,110 for not only do they lay their eggs exposed and unprotected on the ground, 40 00:05:05,450 --> 00:05:08,580 but their young remain flightless for several weeks after hatching 41 00:05:08,740 --> 00:05:12,200 and a hungry cat could cause havoc among them. 42 00:05:12,870 --> 00:05:16,830 So terns find it well worthwhile, for the sake of such security, 43 00:05:17,040 --> 00:05:20,880 to fly hundreds of miles to this island. 44 00:05:37,190 --> 00:05:42,480 The plants that grow on remote islands like Aldabra... how do they get here? 45 00:05:42,860 --> 00:05:45,320 Well, some certainly come by sea. 46 00:05:45,610 --> 00:05:48,240 In a short walk along this high-water mark, 47 00:05:48,410 --> 00:05:52,790 I've picked up already three different kinds of seeds. 48 00:05:53,200 --> 00:05:59,000 Here's the biggest floating seed of them all. This is a coconut. 49 00:06:01,630 --> 00:06:05,170 There's the familiar nut which contains the white flesh, 50 00:06:05,340 --> 00:06:11,760 and this husk, from which we sometimes make coconut mats, is the flotation device. 51 00:06:13,720 --> 00:06:19,560 Nuts like this can float in the sea for up to four months. This one is dead... 52 00:06:20,650 --> 00:06:25,070 ...but here is one that's alive and still sprouting 53 00:06:26,110 --> 00:06:31,070 The green stem springing from the top, a white rootlet striking down underneath. 54 00:06:31,530 --> 00:06:36,750 Under natural conditions, coconuts establish themselves at the head of the beach. 55 00:06:37,210 --> 00:06:41,460 As they grow taller, they lean out over the sand so that when they're full-grown, 56 00:06:41,630 --> 00:06:44,590 their nuts will drop within reach of the high tide 57 00:06:44,800 --> 00:06:48,720 and be washed out to sea to spread to other islands. 58 00:06:51,300 --> 00:06:54,430 A land-living animal also reached here by sea. 59 00:06:54,770 --> 00:06:58,980 The time and place to find it is at night among the coconut groves. 60 00:06:59,350 --> 00:07:04,940 It travelled here as a larva in the same way as the coconuts, floating in the surface waters. 61 00:07:05,320 --> 00:07:07,490 One or two in a million were washed up on the beach 62 00:07:07,650 --> 00:07:14,030 and crawled ashore to live on land among the coconuts, feeding on them. 63 00:07:14,790 --> 00:07:18,080 It's almost the only creature here likely to give you a painful bite, 64 00:07:18,250 --> 00:07:20,170 so it needs tackling with care. 65 00:07:21,670 --> 00:07:23,460 It's the coconut crab. 66 00:07:34,510 --> 00:07:38,770 Its legs are so long that it can embrace the trunk of a coconut palm, 67 00:07:38,930 --> 00:07:42,440 and it has no difficulty in clambering up to the top. 68 00:07:42,810 --> 00:07:45,730 There it cuts down young nuts with its pincers, 69 00:07:45,900 --> 00:07:50,200 and returns to the ground to feed on the soft white coconut flesh. 70 00:07:50,700 --> 00:07:55,870 Crabs as a group are sea-living creatures and breathe in water by means of gills. 71 00:07:56,330 --> 00:08:00,580 To breathe in air, the coconut crab has developed large pouches within its shell 72 00:08:00,750 --> 00:08:04,670 that have moist linings and can act as simple lungs. 73 00:08:05,290 --> 00:08:08,340 But when it breeds, it has to return to the sea. 74 00:08:08,710 --> 00:08:12,260 There it releases its eggs and sperm into the water at high tide, 75 00:08:12,430 --> 00:08:15,550 so that its larvae will circulate through the sea, 76 00:08:15,850 --> 00:08:18,850 and may be washed up on some new island. 77 00:08:28,650 --> 00:08:33,490 One exceptional land animal made the voyage to Aldabra as an adult: 78 00:08:33,660 --> 00:08:37,410 Its most famous inhabitant, the giant tortoise. 79 00:08:38,290 --> 00:08:40,540 Most tortoises are naturally buoyant. 80 00:08:40,790 --> 00:08:46,460 If one on the coast of mainland Africa, grazing among the mangroves, were swept out to sea, 81 00:08:46,670 --> 00:08:51,510 it might survive long enough to be carried by currents to the islands of the Indian Ocean, 82 00:08:51,720 --> 00:08:53,470 and later to spread among them. 83 00:08:53,680 --> 00:08:59,720 That, almost certainly, is how ancestors of the Aldabran giant tortoise reached here. 84 00:09:02,270 --> 00:09:06,520 It's not a very hospitable place for animals like tortoises 85 00:09:06,690 --> 00:09:09,190 that feed on land-living plants. 86 00:09:09,820 --> 00:09:12,780 The coral rock which forms the substance of the island 87 00:09:12,950 --> 00:09:17,450 erodes into a honeycomb of wickedly sharp blades and spikes. 88 00:09:18,530 --> 00:09:24,500 Any creature moving over it has to step with care if it's not to cut itself badly. 89 00:09:38,050 --> 00:09:43,430 Here and there, the rock forms deep pits into which tortoises sometimes tumble. 90 00:09:43,810 --> 00:09:46,350 When that happens, there is no escape, 91 00:09:46,520 --> 00:09:52,030 and the trapped animals, even if they survive the fall, die from starvation 92 00:09:54,610 --> 00:10:00,370 Quite apart from such traps, the island is a harsh, taxing place in which to live. 93 00:10:00,950 --> 00:10:06,920 The tropical sun, beating down on the animals, threatens to bake them alive inside their shells, 94 00:10:07,080 --> 00:10:09,500 and the remains of casualties are common. 95 00:10:14,510 --> 00:10:16,220 So as the day heats up, 96 00:10:16,380 --> 00:10:21,680 the tortoises head determinedly for the few trees that can provide shade. 97 00:10:23,520 --> 00:10:29,480 Here and there on some beaches grow low, windswept Guettarda trees. 98 00:10:30,520 --> 00:10:35,150 By noon, the ground beneath their branches is packed with refugees from the sun, 99 00:10:35,320 --> 00:10:41,370 waiting for the temperature to fall so that they can search for edible leaves. 100 00:10:45,080 --> 00:10:47,370 Birds, too, can overheat. 101 00:10:48,620 --> 00:10:53,500 The frigates swoop over the one almost permanent lagoon of rainwater on the island, 102 00:10:53,670 --> 00:10:56,380 snatching sips from its surface. 103 00:11:24,910 --> 00:11:27,450 Tortoises, too, must have fresh water. 104 00:11:27,790 --> 00:11:29,410 Although they don't drink every day, 105 00:11:29,620 --> 00:11:33,000 they must do every week or so if they're to survive. 106 00:11:51,350 --> 00:11:54,820 Water can also cool an overheated body. 107 00:11:59,900 --> 00:12:01,570 As the dry season progresses, 108 00:12:01,780 --> 00:12:06,700 the water evaporates and the pools get smaller and more crowded. 109 00:12:42,150 --> 00:12:46,660 Many that came here for relief are near the end of their strength. 110 00:12:46,910 --> 00:12:52,540 Some are unable to drag themselves out of the mud, and so die of starvation. 111 00:13:05,340 --> 00:13:10,720 And yet, in spite of all these hardships, the tortoises breed and proliferate. 112 00:13:11,020 --> 00:13:14,390 There are some 150,000 of them on the atoll. 113 00:13:15,060 --> 00:13:20,650 Their staple food is vegetation and they crop the grass right down to the rootstock. 114 00:13:26,410 --> 00:13:29,200 But as island animals everywhere tend to do, 115 00:13:29,450 --> 00:13:34,670 they've broadened their taste in food to include almost anything that is edible, 116 00:13:35,170 --> 00:13:38,710 including the carcasses of their dead companions. 117 00:13:48,550 --> 00:13:52,520 Flesh is too nutritious to be allowed to rot and go to waste 118 00:13:52,680 --> 00:13:55,690 in this land where there is so little to eat. 119 00:14:07,490 --> 00:14:12,620 50,000 years, which is the time, apparently, that Aldabra has been above the sea, 120 00:14:12,910 --> 00:14:16,000 is not a very long time in terms of evolution. 121 00:14:16,290 --> 00:14:19,960 Nonetheless, 50,000 years of isolation on the island 122 00:14:20,130 --> 00:14:24,510 has brought changes to many plants and animals that live here. 123 00:14:24,800 --> 00:14:27,630 They've begun to take on their own character, 124 00:14:27,890 --> 00:14:33,430 so now they differ slightly both from the ancestors which colonised the island 125 00:14:33,640 --> 00:14:37,230 and from their nearest relations elsewhere in the world. 126 00:14:38,480 --> 00:14:42,650 For example, this close-cropped withered turf around me 127 00:14:42,820 --> 00:14:46,070 contains about 20 different species of plants. 128 00:14:46,360 --> 00:14:51,490 All have been relentlessly cropped by giant tortoises like that. 129 00:14:51,740 --> 00:14:56,500 And look, for example, at this little sedge. 130 00:14:57,540 --> 00:15:04,000 Most sedges bear their flowers at the top of stems that rise quite high above the leaves. 131 00:15:04,380 --> 00:15:10,340 Flowers sticking up like this would not survive long on Aldabra. The tortoises would eat them. 132 00:15:10,590 --> 00:15:14,970 These Aldabran sedges bear their flowers and develop their seeds 133 00:15:15,140 --> 00:15:20,270 close to the rootstock where the jaws of the hungry tortoises can't reach them. 134 00:15:22,480 --> 00:15:27,820 The changes that take place in an island species are not always directly useful like that. 135 00:15:28,200 --> 00:15:31,320 Another of Aldabra's plants has changed in a way 136 00:15:31,490 --> 00:15:34,790 that seems to have no practical significance at all. 137 00:15:35,200 --> 00:15:38,000 This is a lily called Lomatophyllum. 138 00:15:38,290 --> 00:15:44,550 It's slightly different in colour from Lomatophyll growing elsewhere, but that's all. 139 00:15:44,800 --> 00:15:46,800 The difference is very trivial. 140 00:15:49,800 --> 00:15:54,810 But some island plants are spectacularly different from their nearest relatives. 141 00:15:55,100 --> 00:15:59,430 Very, very rarely, extraordinary double nuts like this 142 00:15:59,640 --> 00:16:04,060 are washed up on the shores of the coral islands of the Indian Ocean. 143 00:16:04,310 --> 00:16:07,530 For centuries, nobody knew where they came from. 144 00:16:07,780 --> 00:16:11,860 Some said they were produced by fantastic palm trees 145 00:16:12,070 --> 00:16:17,080 that grew under the surface of the sea, so they were called coco-de-mer. 146 00:16:17,330 --> 00:16:22,330 People believed that their kernels could be made into irresistible love potions 147 00:16:22,500 --> 00:16:25,250 and that their shells, when turned into a cup, 148 00:16:25,420 --> 00:16:29,720 would render the most powerful poison harmless. 149 00:16:29,970 --> 00:16:34,090 A single nut like this was literally worth a king's ransom. 150 00:16:34,340 --> 00:16:36,680 It wasn't until the 18th century 151 00:16:36,850 --> 00:16:40,560 that people discovered that the palms that produced these nuts 152 00:16:40,770 --> 00:16:48,360 grew in one tiny group of islands in the Seychelles, some 700 miles from Aldabra. 153 00:16:49,320 --> 00:16:55,030 The largest surviving group of these trees stands on the little island of Praslin. 154 00:17:29,110 --> 00:17:31,740 There are male and female trees. 155 00:17:32,490 --> 00:17:36,370 The males produce small yellow flowers on long spikes, 156 00:17:36,700 --> 00:17:41,120 and on them lives a little gecko, feeding on their nectar and pollen. 157 00:17:42,250 --> 00:17:44,580 Once again, it's an island original, 158 00:17:44,830 --> 00:17:49,210 slightly different in colour from others in neighbouring islands. 159 00:17:51,130 --> 00:17:55,840 The female flowers start as small reddish buds, no bigger than a man's fist, 160 00:17:56,140 --> 00:18:01,350 but they will develop into the biggest seed produced by any plant. 161 00:18:08,690 --> 00:18:12,230 It takes seven years for the nuts to develop, 162 00:18:12,530 --> 00:18:17,610 and when they are mature, they are so large and so heavy 163 00:18:17,780 --> 00:18:20,830 that almost the only way of opening them is with a saw. 164 00:18:21,030 --> 00:18:25,660 Inside, you can see how very different they are from coconuts. 165 00:18:25,960 --> 00:18:29,080 Not only do they have two lobes to them, 166 00:18:29,290 --> 00:18:33,800 but the nut itself is full solid with flesh. 167 00:18:34,050 --> 00:18:39,010 Flesh that is so heavy that these mature nuts won't float in sea water. 168 00:18:39,180 --> 00:18:41,010 Indeed, sea water kills them. 169 00:18:42,180 --> 00:18:44,600 And that means two things. 170 00:18:44,980 --> 00:18:50,860 First of all, that these palms have never been able to spread to other islands, 171 00:18:51,110 --> 00:18:55,530 and secondly, that they must have actually evolved here. 172 00:18:56,570 --> 00:18:59,780 Isolation changes not only plants but animals. 173 00:18:59,990 --> 00:19:06,160 On Aldabra, wandering among the tortoises are sacred ibis with light blue eyes. 174 00:19:06,410 --> 00:19:08,580 Others elsewhere have dark eyes. 175 00:19:08,830 --> 00:19:14,800 The Aldabran ibis breed among themselves and feed on small shore creatures. 176 00:19:15,210 --> 00:19:17,590 Land crabs are far too big to be eaten, 177 00:19:17,760 --> 00:19:20,970 but they have to be pecked to clear them out of the way. 178 00:19:25,350 --> 00:19:30,690 Several species of Aldabran birds have developed slight variations that make them unique. 179 00:19:30,900 --> 00:19:36,570 The kestrel here is slightly smaller than the Madagascar species, but otherwise the same. 180 00:19:36,780 --> 00:19:41,780 The Aldabran sunbird, however, is a little darker than its African relations. 181 00:19:51,880 --> 00:19:56,090 But perhaps the most dramatic and certainly the most endearing quality 182 00:19:56,260 --> 00:20:01,220 brought to some of the birds of Aldabra by isolation is this. 183 00:20:03,300 --> 00:20:07,020 Not only extreme tameness, but flightlessness. 184 00:20:07,270 --> 00:20:09,480 This is the Aldabran rail. 185 00:20:09,850 --> 00:20:12,020 Flying takes a lot of energy. 186 00:20:12,270 --> 00:20:16,320 It's of obvious value when escaping ground-living enemies, 187 00:20:16,480 --> 00:20:20,610 but there are no such enemies on Aldabra or other remote islands. 188 00:20:20,900 --> 00:20:25,700 So some birds that reach such islands by air have given up flying. 189 00:20:25,950 --> 00:20:30,540 Their wing muscles have dwindled and they can't fly even if they wanted to. 190 00:20:30,830 --> 00:20:33,000 The Aldabran rail is only one example. 191 00:20:34,840 --> 00:20:39,840 A kind of pigeon once lived on another island in the Indian Ocean: Mauritius. 192 00:20:40,220 --> 00:20:43,930 It, too, became flightless and grew as big as a turkey. 193 00:20:44,390 --> 00:20:50,230 It was so tame that European sailors were able to kill it with clubs. 194 00:20:50,600 --> 00:20:54,690 They called it the dodo, and in less than 200 years after finding it, 195 00:20:54,860 --> 00:20:56,900 they'd exterminated it. 196 00:20:58,780 --> 00:21:00,900 Grazing alongside the dodo in Mauritius, 197 00:21:01,070 --> 00:21:06,160 and living in other islands in the Indian Ocean as well, were giant tortoises. 198 00:21:06,450 --> 00:21:11,910 They, too, were taken for food by seamen and were exterminated. 199 00:21:12,290 --> 00:21:16,130 But Aldabra is so remote that few ships come near it, 200 00:21:16,290 --> 00:21:19,460 and here alone, the tortoises have survived. 201 00:21:21,970 --> 00:21:27,430 It seems likely that the African ancestors of these creatures were of a normal size, 202 00:21:27,600 --> 00:21:32,270 and that these tortoises became giants as a consequence of living on islands. 203 00:21:35,480 --> 00:21:39,570 Isolation may have had another effect on the tortoises as well. 204 00:21:39,940 --> 00:21:42,190 When African tortoises are threatened, 205 00:21:42,360 --> 00:21:46,870 they behave in the same way as this baby Aldabran tortoise. 206 00:21:47,070 --> 00:21:49,280 They first pull in their head, 207 00:21:49,450 --> 00:21:53,290 and then they pull after it their heavily armoured front legs 208 00:21:53,460 --> 00:21:59,460 so that nothing sticks out and they're comparatively safe from their enemies. 209 00:21:59,710 --> 00:22:04,050 But when the Aldabran tortoise grows up, its proportions change, 210 00:22:04,260 --> 00:22:05,800 as this one's have done. 211 00:22:06,010 --> 00:22:12,060 This one is now so big that these huge legs won't fit into this space, 212 00:22:12,270 --> 00:22:15,690 so that whatever it does, something sticks out. 213 00:22:15,850 --> 00:22:20,190 It's a fair bet that if there was a hyena on the island, 214 00:22:20,360 --> 00:22:23,030 it would make a meal of the giant tortoise. 215 00:22:23,490 --> 00:22:27,030 But there isn't on Aldabra, so this creature's safe. 216 00:22:29,490 --> 00:22:32,870 Just why the island tortoises should have grown so huge, 217 00:22:33,080 --> 00:22:36,920 and another species has done the same in the Galapagos islands, 218 00:22:37,080 --> 00:22:38,920 is by no means clear. 219 00:22:40,000 --> 00:22:42,840 It may be that a large animal with big reserves of fat 220 00:22:43,010 --> 00:22:47,220 is better able to survive bad seasons when there's little to eat. 221 00:22:47,550 --> 00:22:50,760 It may even be that with no predators on the island, 222 00:22:50,930 --> 00:22:53,560 these long-lived creatures just go on growing, 223 00:22:53,720 --> 00:22:57,440 but it is not a phenomenon that is restricted to tortoises. 224 00:22:57,690 --> 00:23:03,940 On an island 3,000 miles away from Aldabra, there is another giant reptile. 225 00:23:06,610 --> 00:23:09,570 Komodo is a small island in Indonesia. 226 00:23:09,950 --> 00:23:12,030 From here, back in the 1920s, 227 00:23:12,200 --> 00:23:16,960 came stories of a huge lizard that became known as the Komodo dragon, 228 00:23:17,120 --> 00:23:20,000 and here the dragons still live. 229 00:23:44,820 --> 00:23:46,360 It's not difficult to find them. 230 00:23:46,530 --> 00:23:50,860 All you need is the carcass of a goat, preferably decayed and smelly, 231 00:23:51,030 --> 00:23:54,030 and the scent will attract them from miles around. 232 00:24:26,360 --> 00:24:31,780 It used to be thought that these very big ones were entirely scavengers, 233 00:24:31,990 --> 00:24:35,030 relying on what carrion they could find, 234 00:24:35,330 --> 00:24:40,540 but now we know that actually they are active killers. 235 00:24:40,870 --> 00:24:50,220 They attack and kill goats, young buffalo, and even on occasion, man. 236 00:24:50,920 --> 00:24:54,430 The reason that I can stand here with relative safety 237 00:24:54,600 --> 00:24:59,890 is that their eyesight is not very good, they are almost deaf, 238 00:25:00,100 --> 00:25:03,520 and they rely on their senses, 239 00:25:03,730 --> 00:25:08,820 primarily on that big yellow tongue which flicks out and tastes the air. 240 00:25:11,070 --> 00:25:16,990 So with any luck, the smell of these dead goats is more powerful than mine, 241 00:25:17,160 --> 00:25:18,790 so they will take no notice of me. 242 00:25:20,290 --> 00:25:25,040 They are, in fact, the kings of their island. They are the top predator. 243 00:25:25,460 --> 00:25:29,090 There is nothing here which preys upon them and is bigger, 244 00:25:30,920 --> 00:25:33,680 and nothing with which they have to share their food. 245 00:25:35,260 --> 00:25:40,430 So, from that point of view, there is no reason why they shouldn't grow big. 246 00:25:41,480 --> 00:25:45,150 And the fact is that there is a positive advantage in growing big, 247 00:25:45,310 --> 00:25:51,400 because the big ones are getting the bigger share of the food. 248 00:25:52,990 --> 00:25:58,450 Not only that, but we now know that these big ones eat small ones. 249 00:25:59,410 --> 00:26:05,540 That perhaps is a reason why, in the isolation of their island, 250 00:26:05,790 --> 00:26:09,460 these kings of Komodo have grown so huge. 251 00:26:11,050 --> 00:26:13,510 And they are indeed immense. 252 00:26:14,010 --> 00:26:19,140 They're related to the water monitors of Asia and Africa and the goannas of Australia, 253 00:26:19,430 --> 00:26:21,010 but they are much more massive, 254 00:26:21,180 --> 00:26:26,940 for whereas two-thirds of the length of these other monitors is taken up by a long thin tail, 255 00:26:27,190 --> 00:26:30,230 the dragon's tail is only about half its length. 256 00:26:30,980 --> 00:26:37,740 Big ones like this can weigh up to 100 pounds and grow to over nine feet long. 257 00:26:44,710 --> 00:26:46,460 Komodo is not, like Aldabra, 258 00:26:46,620 --> 00:26:50,090 a coral atoll growing on the drowned tip of a submarine volcano, 259 00:26:50,290 --> 00:26:55,470 but the eroded remains of one that stood many thousands of feet above sea level. 260 00:26:57,010 --> 00:27:00,800 Volcanoes, indeed, have built many of the most isolated islands. 261 00:27:01,050 --> 00:27:04,810 The Hawaiian islands, lying in the eastern Pacific, are all volcanic, 262 00:27:04,980 --> 00:27:08,520 and the biggest and newest of them is still erupting. 263 00:27:38,800 --> 00:27:44,140 Torrents of basaltic lava erupting from vents 10,000 feet up on the mountain 264 00:27:44,310 --> 00:27:47,980 sometimes flow for many miles down the volcano's flanks. 265 00:28:06,700 --> 00:28:09,080 When, eventually, they cool and solidify, 266 00:28:09,250 --> 00:28:13,210 they become vast slopes of black naked rock. 267 00:28:16,000 --> 00:28:21,090 Such areas as this may remain virtually sterile for decades. 268 00:28:24,260 --> 00:28:30,850 Some vents produce vast quantities of granular ash which builds up around them into cones. 269 00:28:31,730 --> 00:28:34,690 Plants have a better chance of getting root on such material, 270 00:28:34,980 --> 00:28:39,570 and within a century or so, the ash slopes may be covered with green. 271 00:28:41,030 --> 00:28:44,450 These high islands collect moisture-laden clouds, 272 00:28:44,620 --> 00:28:48,580 and on the windward side, rain falls very heavily indeed. 273 00:28:49,580 --> 00:28:51,920 Streams flowing down the mountainside 274 00:28:52,080 --> 00:28:57,170 cut through the layers of loosely compacted ash, eroding deep valleys. 275 00:28:57,340 --> 00:28:59,510 So, unlike a coral atoll, 276 00:28:59,720 --> 00:29:03,720 which is a plain platform of coral, sand and rock only a few feet high, 277 00:29:03,890 --> 00:29:06,760 these immense volcanic islands of Hawaii 278 00:29:06,930 --> 00:29:10,310 offered their colonists a great variety of habitat 279 00:29:10,480 --> 00:29:13,150 from high cold slopes of ash on the summits 280 00:29:13,350 --> 00:29:18,230 to well-watered valleys, hot, lush and humid, near sea level, 281 00:29:18,820 --> 00:29:24,160 from new, naked basalt to long-established forest growing on ancient lava flows. 282 00:29:24,450 --> 00:29:32,160 To exploit them, the animal colonists changed not into just one new form, but into a multitude. 283 00:29:35,000 --> 00:29:36,460 This bird, the palila, 284 00:29:36,670 --> 00:29:40,960 is one of a large family of closely related Hawaiian birds, the honeycreepers. 285 00:29:41,380 --> 00:29:45,550 Their ancestors were probably finch-like birds that were swept here, 286 00:29:45,840 --> 00:29:49,180 perhaps by a freak storm many thousands of years ago. 287 00:29:49,430 --> 00:29:52,890 Once here, they developed into over 30 different species, 288 00:29:53,060 --> 00:29:55,350 each with its own diet and habitat. 289 00:29:55,850 --> 00:29:57,900 The palila lives largely on seeds 290 00:29:58,070 --> 00:30:02,650 and has the short, powerful beak needed to open and crack them. 291 00:30:08,120 --> 00:30:14,160 The 'amakihi, while there's no doubt that it and the palila are related, 292 00:30:14,370 --> 00:30:17,920 has a slender beak, suited to picking up small insects 293 00:30:18,090 --> 00:30:20,590 and sipping nectar from shallow flowers. 294 00:30:21,090 --> 00:30:25,220 Some species have developed striking feather colours and adornments. 295 00:30:25,470 --> 00:30:28,470 These enable the male and female to identify one another 296 00:30:28,640 --> 00:30:31,640 so they don't interbreed with near cousins, 297 00:30:31,850 --> 00:30:34,390 and the species becomes increasingly distinct. 298 00:30:35,690 --> 00:30:41,480 So the 'apapane not only has a longer beak to suit its almost exclusive diet of nectar, 299 00:30:41,690 --> 00:30:43,690 but a conspicuous red head. 300 00:30:45,610 --> 00:30:49,740 The 'akohekohe lives on a mixed diet of insects and nectar, 301 00:30:49,910 --> 00:30:53,870 and has developed a little crest of white feathers at the base of its beak. 302 00:30:58,420 --> 00:31:02,880 The 'i'iwi is scarlet and has a particularly long curved bill 303 00:31:03,090 --> 00:31:06,800 that allows it to probe deep into trumpet-shaped flowers 304 00:31:06,970 --> 00:31:09,850 such as giant lobelias and bananas. 305 00:31:20,650 --> 00:31:25,030 And perhaps most engaging of all, the akiapolaau, 306 00:31:25,190 --> 00:31:27,780 with a splendid dual-purpose beak, 307 00:31:27,990 --> 00:31:32,080 the lower mandible pick-like to chip away bark to find insects, 308 00:31:32,240 --> 00:31:37,160 and an upper mandible elongated into a probe with which to winkle them out. 309 00:31:41,290 --> 00:31:45,010 It's located a beetle larva burrowing away within the bark. 310 00:31:45,300 --> 00:31:50,680 Look how dexterously it uses the two halves of its beak for these different purposes. 311 00:32:04,900 --> 00:32:09,820 The situation amongst Hawaii's insects is even more extreme than it is among its birds. 312 00:32:10,200 --> 00:32:15,080 There is a kind of fly called Drosophila. It's found in many parts of the world. 313 00:32:15,240 --> 00:32:19,120 In North America, for example, there are about 200 species, 314 00:32:19,290 --> 00:32:25,340 but in these tiny islands of Hawaii, there are at least 800. 315 00:32:26,300 --> 00:32:30,010 It seems that soon after the islands' formation, 316 00:32:30,180 --> 00:32:35,140 one or at most two species of Drosophila reached the islands, 317 00:32:35,310 --> 00:32:40,100 and they found the same situation as the honeycreepers found, a lot of vacant niches. 318 00:32:40,350 --> 00:32:44,860 And so they evolved to fill them, and they are now Drosophila, 319 00:32:45,070 --> 00:32:50,990 the larvae of which feed on fruit or rotting leaves or fungi, 320 00:32:51,160 --> 00:32:53,950 or bark or even spiders' eggs. 321 00:32:54,320 --> 00:33:00,370 But now the situation becomes more complex because in Hawaii, there are lava flows like this, 322 00:33:00,960 --> 00:33:06,960 and such lava flows often isolate patches of ancient forest like that over there, 323 00:33:07,170 --> 00:33:09,420 and in one small patch of forest, 324 00:33:09,670 --> 00:33:16,220 there may well be one particular species of Drosophila that occurs nowhere else. 325 00:33:40,580 --> 00:33:43,370 And there are some just there. 326 00:33:53,470 --> 00:33:58,260 These particular ones belong to a group which have evolved, in their isolation, 327 00:33:58,470 --> 00:34:00,520 an extraordinary courtship behaviour, 328 00:34:00,680 --> 00:34:03,980 just as some honeycreepers have evolved bright colours. 329 00:34:04,560 --> 00:34:07,690 It's an insect equivalent of the arena display of antelope. 330 00:34:07,900 --> 00:34:13,820 The males maintain tiny territories and display and battle with one another. 331 00:34:14,400 --> 00:34:18,530 Instead of antlers, they've developed heads shaped like mallets. 332 00:34:27,750 --> 00:34:31,920 In another species, the male courts the female by hoisting his abdomen over his back 333 00:34:32,090 --> 00:34:35,220 and showering her with an aphrodisiac perfume. 334 00:34:38,220 --> 00:34:41,850 Isolation has also affected the wings of Hawaiian insects. 335 00:34:42,060 --> 00:34:44,140 Flying on an island is dangerous. 336 00:34:44,390 --> 00:34:46,730 It risks being blown out to sea, 337 00:34:48,400 --> 00:34:51,650 and this extraordinary bug never takes to the air. 338 00:34:52,150 --> 00:34:56,240 Its wings are tiny, and used only for flirting in courtship. 339 00:34:59,740 --> 00:35:01,990 This lacewing can't even use them for that. 340 00:35:02,240 --> 00:35:05,330 Its wings have become fused together to form a shell. 341 00:35:06,170 --> 00:35:10,000 The Hawaiian cranefly has lost its wings completely. 342 00:35:10,670 --> 00:35:13,670 This cranefly's taste for fruit is typical of its family, 343 00:35:13,840 --> 00:35:16,970 but other insects have changed their feeding habits. 344 00:35:17,300 --> 00:35:21,100 This flightless bug has adopted the hunting techniques of the mantis 345 00:35:21,310 --> 00:35:23,470 which never naturally reached the island. 346 00:35:26,810 --> 00:35:29,230 And this fly is going to get a shock. 347 00:35:32,270 --> 00:35:35,610 The twig caterpillar doesn't, like most twig caterpillars elsewhere, 348 00:35:35,820 --> 00:35:38,530 feed on leaves, but has become a carnivore. 349 00:35:50,290 --> 00:35:53,880 It detected the fly with tiny hairs on its back en 350 00:35:54,130 --> 00:35:58,720 They trigger the caterpillar to arch backwards and pounce on whatever touched it. 351 00:36:03,100 --> 00:36:07,770 So isolation, by restricting the kinds of creature that reached Hawaii, 352 00:36:07,940 --> 00:36:14,070 allows those that did great freedom to develop into different and unexpected forms. 353 00:36:17,320 --> 00:36:22,570 Human beings, the Polynesians, reached Hawaii several thousand years ago. 354 00:36:22,950 --> 00:36:25,740 When Europeans arrived, they found to their surprise 355 00:36:25,950 --> 00:36:29,750 an unknown people with an elaborate and splendid culture. 356 00:36:30,370 --> 00:36:32,330 The Hawaiians were superb seamen. 357 00:36:32,670 --> 00:36:34,800 They not only paddled dugout canoes, 358 00:36:35,000 --> 00:36:40,380 but sailed immense ocean-going double canoes that could carry several hundred passengers, 359 00:36:40,680 --> 00:36:44,850 and that tradition survives still in many parts of the Pacific. 360 00:36:56,690 --> 00:37:02,530 The last of the really big canoes must have disappeared about 100 years ago, 361 00:37:02,780 --> 00:37:05,580 but still, in the remoter parts of the Pacific, 362 00:37:05,830 --> 00:37:09,710 people remembered the techniques that were used to sail them, 363 00:37:09,870 --> 00:37:13,540 and still practise the skills needed to build them 364 00:37:13,880 --> 00:37:17,880 This particular canoe, which is very big for modern times, 365 00:37:18,090 --> 00:37:24,300 was built on the tiny island of Ribono in Kiribati the islands that used to be called the Gilberts. 366 00:37:24,640 --> 00:37:30,980 It is only about 50 feet long, enormous for today, but only half the size of the old canoes, 367 00:37:31,140 --> 00:37:37,480 and still the people are prepared to sail on journeys of up to 1,000 miles in it. 368 00:37:37,730 --> 00:37:43,780 The techniques for building it are those that were used for the old canoes. 369 00:37:44,030 --> 00:37:45,990 The lashings, for instance. 370 00:37:46,200 --> 00:37:49,240 They are made from the fibres of coconut husks. 371 00:37:49,830 --> 00:37:52,660 Clumps are teased out, rolled and twisted 372 00:37:52,830 --> 00:37:55,460 so that each fibre binds with its neighbours. 373 00:37:55,750 --> 00:38:00,130 It is a repetitious job, but a skilled one if the string is going to be strong, 374 00:38:00,340 --> 00:38:03,380 and it is taken on by the women and the old people. 375 00:38:03,630 --> 00:38:07,680 Hundreds of yards will be needed to build a big canoe. 376 00:38:14,650 --> 00:38:17,730 It's used not only for lashing one spar to another 377 00:38:17,900 --> 00:38:22,780 but for sewing together the planks that form the sides of the big canoes. 378 00:38:49,720 --> 00:38:54,730 The Pandanus tree produces strap-like leaves, which, when dried and split, 379 00:38:54,940 --> 00:39:00,730 provide ribbons that are woven into strong and durable mats to serve as sails. 380 00:39:10,450 --> 00:39:13,080 So if you have the necessary knowledge and skill, 381 00:39:13,250 --> 00:39:19,460 even a small atoll can provide all the materials to build an ocean-going canoe. 382 00:39:20,420 --> 00:39:24,010 In such craft, the Polynesians travelled right across the Pacific. 383 00:39:24,510 --> 00:39:28,470 For a long time, Europeans, so proud of their navigating skills, 384 00:39:28,640 --> 00:39:31,760 maintained that the Polynesian voyages were accidental, 385 00:39:31,930 --> 00:39:34,390 made when fishing canoes were blown off course. 386 00:39:35,020 --> 00:39:41,480 But the huge canoes carried women and children, and were loaded with plants and animals, 387 00:39:41,650 --> 00:39:45,030 with every intention of founding new colonies. 388 00:39:46,570 --> 00:39:51,450 The Polynesian navigators had and have the most astonishing powers of observation 389 00:39:51,620 --> 00:39:53,290 by which they find their way. 390 00:39:54,370 --> 00:39:57,210 A particular kind of bird during one season of the year 391 00:39:57,370 --> 00:40:00,080 will always travel in a certain direction. 392 00:40:00,710 --> 00:40:05,590 Some birds are ocean-goers, others seldom travel far from their nesting grounds, 393 00:40:05,800 --> 00:40:10,390 so spotting one can indicate that there's land close by, 394 00:40:10,550 --> 00:40:12,970 and following it may take you there. 395 00:40:16,310 --> 00:40:17,980 Distant islands can be detected 396 00:40:18,190 --> 00:40:21,770 by their effect on the ripples on the surface of the sea. 397 00:40:22,860 --> 00:40:25,730 Tall islands trail clouds of characteristic shape 398 00:40:25,940 --> 00:40:28,490 like smoke from a chimney blown by the wind, 399 00:40:28,650 --> 00:40:30,700 and since they are so high in the sky, 400 00:40:30,860 --> 00:40:35,620 they can be recognised and identified long before the island is visible. 401 00:40:37,080 --> 00:40:42,130 Using such techniques and observing the sun and stars, the pattern of the winds, 402 00:40:42,330 --> 00:40:45,670 and feeling through the rudder the movements of swells and currents, 403 00:40:45,880 --> 00:40:49,010 the Polynesians colonised island after island. 404 00:40:49,380 --> 00:40:51,760 Their original home was in the western Pacific. 405 00:40:51,930 --> 00:40:57,310 They reached the Tahitian islands, in the centre of the ocean, over 2,000 years ago. 406 00:41:00,440 --> 00:41:04,570 They sailed so far eastward that they reached Easter Island, 407 00:41:04,770 --> 00:41:07,610 three-quarters of the way to the coast of South America. 408 00:41:09,360 --> 00:41:12,610 Those that settled here seem to have been more isolated than most, 409 00:41:12,780 --> 00:41:17,830 and, like so many other islanders, they developed their own culture. 410 00:41:18,290 --> 00:41:21,620 They carved the rocks of their headlands into strange shapes. 411 00:41:22,210 --> 00:41:24,960 On the flanks of the great volcano that built their island, 412 00:41:25,170 --> 00:41:31,220 they set up huge images whose enigmatic faces have haunted the European imagination 413 00:41:31,430 --> 00:41:35,680 ever since they were discovered by westerners two centuries ago. 414 00:41:48,230 --> 00:41:50,490 The heyday of the Easter Island culture 415 00:41:50,650 --> 00:41:54,240 seems to have been passed long before Europeans arrived, 416 00:41:54,570 --> 00:42:00,790 for many statues were overturned and some lay half-finished and abandoned 417 00:42:00,950 --> 00:42:03,620 where they had been carved in the quarries. 418 00:42:14,470 --> 00:42:18,430 The scale of these Polynesian voyages is difficult to imagine. 419 00:42:18,640 --> 00:42:24,480 From their headquarters in Samoa to their most northerly colony in Hawaii, 420 00:42:24,650 --> 00:42:29,110 which they reached by way of the Marquesas, was some 5,000 miles. 421 00:42:30,030 --> 00:42:34,280 The journey to Easter Island, about 3,300 miles. 422 00:42:34,740 --> 00:42:36,740 But the most extraordinary voyage of all 423 00:42:36,910 --> 00:42:42,580 took them across 4,000 miles of open ocean, south to New Zealand. 424 00:42:44,210 --> 00:42:47,630 The group that landed here, ancestors of the Maori, 425 00:42:47,790 --> 00:42:51,210 arrived about 1,500 years ago. 426 00:42:52,210 --> 00:42:55,550 The land they discovered must have been a great surprise to them, 427 00:42:55,760 --> 00:43:00,010 for it was very different from the tropical island from which they had come. 428 00:43:00,850 --> 00:43:03,680 For much of the year, it was bitterly cold. 429 00:43:04,730 --> 00:43:09,400 In the South Island stood great mountain ranges covered with snow and ice 430 00:43:09,610 --> 00:43:12,360 that the Maori can never have seen before. 431 00:43:14,030 --> 00:43:19,200 Not only that, but the forests were far richer in animals and plants 432 00:43:19,410 --> 00:43:21,790 than any island they had yet discovered. 433 00:43:22,240 --> 00:43:26,620 That was because these islands had a very different origin and history. 434 00:43:27,830 --> 00:43:32,170 They were neither flat coral atolls nor were they the tips of volcanoes 435 00:43:32,340 --> 00:43:37,590 that had risen above the surface of the Pacific in comparatively recent geological time. 436 00:43:38,510 --> 00:43:41,180 These islands of New Zealand were ancient lands. 437 00:43:41,350 --> 00:43:43,430 Fragments of a great supercontinent 438 00:43:43,600 --> 00:43:48,150 of which Australia, Antarctica and South America had been a part. 439 00:43:48,480 --> 00:43:53,530 In consequence, they had on them many more different kinds of animals 440 00:43:53,690 --> 00:43:55,570 than other more recent islands. 441 00:43:55,860 --> 00:43:58,820 They had animals like this. 442 00:44:00,410 --> 00:44:02,660 This is the tuatara. 443 00:44:03,080 --> 00:44:09,040 It's a reptile, it's nocturnal and solitary, and it's a flesh-eater. 444 00:44:09,420 --> 00:44:15,340 It feeds on insects, earthworms and even young nestling birds. 445 00:44:16,090 --> 00:44:20,970 It might look like a lizard, but it's a more ancient creature than that, 446 00:44:21,180 --> 00:44:23,640 more closely related to the early dinosaurs 447 00:44:23,810 --> 00:44:26,230 than it is to the modern family of lizards. 448 00:44:26,600 --> 00:44:31,100 Once creatures like it must have swarmed over that great supercontinent, 449 00:44:31,270 --> 00:44:34,820 but New Zealand split away from the supercontinent 450 00:44:35,030 --> 00:44:37,150 before the great expansion of the early mammals 451 00:44:37,320 --> 00:44:41,700 which ultimately led to the extinction of most of the early reptiles. 452 00:44:41,950 --> 00:44:47,120 Only in New Zealand did the tuatara remain safe. 453 00:44:47,870 --> 00:44:52,840 And New Zealand also has been a sanctuary for another early creature. 454 00:44:55,090 --> 00:44:58,670 The kiwi. It's a bird, but what an odd one. 455 00:44:59,010 --> 00:45:03,470 It has no visible wings and no tail and lives in a burrow. 456 00:45:08,270 --> 00:45:12,480 There, it produces a single and enormous egg. 457 00:45:20,150 --> 00:45:22,110 Flightless, living in burrows, 458 00:45:22,280 --> 00:45:26,410 with feathers so long and loose they look like shaggy fur, 459 00:45:26,620 --> 00:45:31,000 and running quietly across the forest floor at night in search of food, 460 00:45:31,210 --> 00:45:35,960 this odd animal could be considered a kind of bird equivalent of a mammal. 461 00:45:36,420 --> 00:45:40,090 Indeed, the kiwi does play that role in these islands 462 00:45:40,380 --> 00:45:44,180 where originally there were no land mammals of any kind. 463 00:45:53,520 --> 00:45:57,820 It has, however, retained that characteristic possession of the bird, a beak... 464 00:45:59,990 --> 00:46:01,700 ...and it uses it to collect worms, 465 00:46:01,860 --> 00:46:06,740 plunging it deep into the earth to smell for them as a mammal does. 466 00:46:10,700 --> 00:46:15,210 The ancestors of the kiwi were flightless before New Zealand was isolated, 467 00:46:15,380 --> 00:46:17,380 for the kiwi is a ratite. 468 00:46:18,550 --> 00:46:22,050 Other members of that family of ancient flightless birds 469 00:46:22,220 --> 00:46:25,680 still survive on other fragments of the great supercontinent. 470 00:46:25,840 --> 00:46:31,390 There's the ostrich in Africa, the rhea in South America and the emu in Australia. 471 00:46:31,730 --> 00:46:34,230 All those are bigger than the kiwi, 472 00:46:34,390 --> 00:46:38,070 but the kiwi once had a cousin living here in New Zealand 473 00:46:38,230 --> 00:46:40,230 that was bigger than the lot of them. 474 00:46:40,480 --> 00:46:45,860 It was probably the tallest bird that has ever existed, the moa. 475 00:46:47,570 --> 00:46:51,250 Its bones have been found in great numbers here in New Zealand. 476 00:46:51,410 --> 00:46:57,420 Often in between the ribs have been found piles of polished pebbles. 477 00:46:57,630 --> 00:47:03,720 They were the stones from the gizzard with which the moa ground up its food, 478 00:47:03,880 --> 00:47:11,270 and from the vegetable remains, we know that it ate fruit, twigs and the leaves of trees. 479 00:47:13,350 --> 00:47:17,770 There were a dozen or so different species of moa of varying sizes. 480 00:47:19,480 --> 00:47:21,980 This particular one was the biggest of all. 481 00:47:22,280 --> 00:47:25,360 It was not the heaviest bird that has ever lived, 482 00:47:25,570 --> 00:47:29,780 its relative, the extinct elephant bird that lived in Madagascar was that, 483 00:47:29,990 --> 00:47:35,040 but its weight nonetheless was substantial, about 520 pounds, 484 00:47:35,250 --> 00:47:40,840 and it was the tallest of all birds, standing over 13 feet high. 485 00:47:41,380 --> 00:47:44,510 In fact, it was the bird equivalent of a giraffe. 486 00:47:47,180 --> 00:47:52,810 This is the mummified head and neck of one of the smaller species of moa, 487 00:47:53,060 --> 00:47:57,770 and it suggests, because many necks have been found attached to heads, 488 00:47:58,020 --> 00:48:00,400 that the Maori had so much moa meat 489 00:48:00,560 --> 00:48:05,150 that they could afford to throw away sections like this. 490 00:48:05,650 --> 00:48:09,620 The Maori not only reduced the number of moa by hunting, 491 00:48:09,820 --> 00:48:14,370 they also burnt down the forests on which the moas depended. 492 00:48:14,660 --> 00:48:19,830 And so, by the time the Europeans arrived here in the 18th century, 493 00:48:20,000 --> 00:48:23,880 the last of the moas had been extinct for some 200 years. 494 00:48:26,510 --> 00:48:31,970 But in the millions of years that have passed since New Zealand was isolated as islands, 495 00:48:32,180 --> 00:48:35,430 many more modern creatures have arrived here. 496 00:48:35,640 --> 00:48:40,850 They've got here, as they've managed to get to islands all over the world, by flying. 497 00:48:42,360 --> 00:48:44,940 Some have changed only a little since they arrived. 498 00:48:45,110 --> 00:48:49,200 The kereru is still quite clearly a kind of pigeon 499 00:48:56,160 --> 00:49:00,210 And this, the kea, is still recognisably a parrot. 500 00:49:01,290 --> 00:49:03,250 Its ancestors came, doubtless, 501 00:49:03,420 --> 00:49:07,710 from that great parrot homeland, Australia, 1,000 miles away. 502 00:49:07,920 --> 00:49:11,590 Since it's been here, it's probably changed its habits a good deal, 503 00:49:11,760 --> 00:49:14,470 for it's taken up life in the cold, high mountains 504 00:49:14,680 --> 00:49:19,310 where it feeds on berries and roots, buds and insects. 505 00:49:28,690 --> 00:49:33,070 It has also, with that adaptability of diet characteristic of islanders, 506 00:49:33,240 --> 00:49:35,280 become a general scavenger, 507 00:49:35,490 --> 00:49:39,410 and will even feed on carrion like a crow or small vulture. 508 00:49:41,500 --> 00:49:46,170 One parrot, here, however, has been changed extremely by island life. 509 00:49:47,210 --> 00:49:48,590 The kakapo. 510 00:49:49,090 --> 00:49:52,180 There are no ground-living leaf-eating mammals on the island, 511 00:49:52,340 --> 00:49:55,970 so this has become a kind of parrot-equivalent of a rabbit. 512 00:49:59,810 --> 00:50:05,520 It's extremely nervous, nocturnal, and it lives on vegetation, 513 00:50:05,730 --> 00:50:11,240 but it shows those two characteristics of island-living creatures. 514 00:50:11,990 --> 00:50:15,030 It has lost its powers of flight, 515 00:50:15,410 --> 00:50:22,040 so its only defence is to freeze motionless as it's doing now. 516 00:50:23,170 --> 00:50:26,380 And secondly, it's a giant. 517 00:50:27,340 --> 00:50:31,090 It's the biggest of all the parrots by weight. 518 00:50:32,380 --> 00:50:36,510 A big one can weigh over three kilos. 519 00:50:38,140 --> 00:50:45,270 It also shows only too vividly a third characteristic of island-living forms: 520 00:50:46,100 --> 00:50:48,900 Their extreme vulnerability. 521 00:50:49,360 --> 00:50:55,740 When their islands are invaded by outsiders, they often have no defence. 522 00:50:56,620 --> 00:51:01,450 The kakapo's troubles started when the Polynesians first came to New Zealand. 523 00:51:01,870 --> 00:51:07,000 They brought a kind of rat which may have preyed upon the nestling kakapo, 524 00:51:07,170 --> 00:51:10,710 and the Polynesians themselves hunted it. 525 00:51:12,090 --> 00:51:16,590 The real catastrophe came when Europeans arrived, 526 00:51:16,800 --> 00:51:23,640 because they brought with them those two merciless killers, the stoat and the cat 527 00:51:24,310 --> 00:51:28,940 Against them, the kakapo had no defence whatever. 528 00:51:29,980 --> 00:51:32,900 Very rapidly, its numbers diminished 529 00:51:33,070 --> 00:51:40,370 until today there are not more than 60 individual kakapo left. 530 00:51:42,160 --> 00:51:44,290 To give them some chance of survival, 531 00:51:44,580 --> 00:51:50,170 they've been taken to a small offshore island that has been cleared of cats. 532 00:51:51,000 --> 00:51:56,510 Elsewhere, these domestic pets that were brought here to catch mice in houses 533 00:51:56,680 --> 00:52:00,180 have run wild in the forests, and prey on native birds 534 00:52:00,390 --> 00:52:05,310 which have not acquired the right reflexes to save themselves from its attacks. 535 00:52:31,340 --> 00:52:34,510 Cats are not the only foreign killers here. 536 00:52:34,800 --> 00:52:37,880 Ferrets were imported for hunting introduced rabbits. 537 00:52:38,340 --> 00:52:40,760 They are domesticated polecats. 538 00:52:41,090 --> 00:52:44,220 Some escaped, reverted to their wild state and bred. 539 00:52:44,680 --> 00:52:49,100 This one is feeding on a penguin chick which must have been an easy victim. 540 00:52:49,310 --> 00:52:53,270 None of New Zealand's flightless birds are safe from them. 541 00:52:55,280 --> 00:52:57,950 People also introduced plant-eating animals. 542 00:52:58,400 --> 00:53:01,490 Possums were brought from Australia as pets. 543 00:53:08,000 --> 00:53:11,790 Rabbits were also imported to provide meat and fur, 544 00:53:12,130 --> 00:53:15,670 and to put to good use, as the importers must have thought, 545 00:53:15,960 --> 00:53:19,340 the abundant grass that was going to waste. 546 00:53:19,840 --> 00:53:24,100 And red deer were released in the mountains to provide hunters with sport. 547 00:53:24,430 --> 00:53:30,060 Yet these seemingly harmless vegetarians had a catastrophic effect on the native animals. 548 00:53:30,810 --> 00:53:35,230 They grazed so effectively that they destroyed the trees and bushes. 549 00:53:35,480 --> 00:53:38,780 The soil was washed away and the forest devastated. 550 00:53:38,940 --> 00:53:43,780 Creatures were robbed of their cover and vegetation. 551 00:53:45,280 --> 00:53:48,660 The problems of halting this destruction are very great. 552 00:53:49,000 --> 00:53:52,370 This extraordinary bird is the takahe. 553 00:53:52,710 --> 00:53:56,840 Like the kakapo, it epitomises the effects of island-living. 554 00:53:57,090 --> 00:54:00,800 It's become a giant, for it's a rail, like the one in Aldabra, 555 00:54:00,970 --> 00:54:03,050 and the biggest of its family. 556 00:54:03,340 --> 00:54:06,560 It's unique to these islands, it's flightless, 557 00:54:06,720 --> 00:54:10,270 and has virtually no defence against invaders. 558 00:54:10,770 --> 00:54:13,980 At the beginning of this century, it was thought to be extinct. 559 00:54:14,270 --> 00:54:18,940 Then, after no one had seen a living takahe for over 50 years, 560 00:54:19,110 --> 00:54:24,110 a small population was discovered in a remote valley in South Island. 561 00:54:25,120 --> 00:54:27,580 There are about 200 left. 562 00:54:27,910 --> 00:54:32,750 They are unlikely to spread, for their habitat elsewhere has been destroyed, 563 00:54:33,000 --> 00:54:36,960 and there is the greatest difficulty in getting them to breed in captivity. 564 00:54:40,210 --> 00:54:47,010 So, unless man is prepared to change his attitude and become an active protector 565 00:54:47,350 --> 00:54:49,100 as he has done here in New Zealand, 566 00:54:49,350 --> 00:54:52,350 those strange specialised islanders 567 00:54:52,520 --> 00:54:57,860 are doomed to the fate of the first island-living creature that man exterminated 568 00:54:58,020 --> 00:55:01,320 and become as dead as the dodo. 569 00:55:01,990 --> 00:55:04,740 Of course, not all the creatures that you find on islands 570 00:55:04,910 --> 00:55:07,780 necessarily spend all their time there. 571 00:55:08,120 --> 00:55:13,460 Some like those tough international travellers over there, the gannets, 572 00:55:13,660 --> 00:55:15,750 just come here for lodging. 573 00:55:17,330 --> 00:55:20,130 They, like the frigates and the boobies of Aldabra, 574 00:55:20,300 --> 00:55:23,550 the noddies and the terns of a thousand tropical atolls, 575 00:55:23,720 --> 00:55:29,720 find their food, not on the islands where they come to nest, but in the surrounding seas.