1 00:00:35,514 --> 00:00:39,143 Modern Australia... lt seems a familiar sort of place... 2 00:00:41,654 --> 00:00:46,023 ...but step outside these cities and you could almost be on another planet. 3 00:00:47,993 --> 00:00:51,485 Because Australia is the strangest continent on earth. 4 00:00:56,302 --> 00:00:58,133 lts wildlife is so weird 5 00:00:58,370 --> 00:01:01,669 that at first some people thought the animals were a hoax... 6 00:01:02,408 --> 00:01:04,376 ...or the work of the devil. 7 00:01:06,779 --> 00:01:09,509 lt's a paradox, a place of extremes - 8 00:01:10,015 --> 00:01:11,778 its centre a burning desert, 9 00:01:13,018 --> 00:01:16,818 but also with rugged mountains, covered in deep winter snow. 10 00:01:22,061 --> 00:01:26,020 lt has endless horizons of magical, time worn landscapes... 11 00:01:31,670 --> 00:01:35,106 ...and in them an amazing variety of wildlife... 12 00:01:40,045 --> 00:01:43,947 ...more species of animals than Europe and North America combined... 13 00:01:44,950 --> 00:01:49,250 ...almost all of them unique - they live nowhere else on earth. 14 00:02:00,232 --> 00:02:02,826 lt's a place that likes to do things differently. 15 00:02:03,235 --> 00:02:06,466 And somehow, this remarkable mix of wildlife 16 00:02:06,639 --> 00:02:11,406 manages to survive on the harshest, driest inhabited continent on earth. 17 00:02:14,346 --> 00:02:17,338 So how did Australia come to be so special? 18 00:02:21,086 --> 00:02:24,249 To answer that, you need to travel back in time to 19 00:02:24,423 --> 00:02:28,189 when this was a very different kind of place, covered in trees. 20 00:02:33,032 --> 00:02:34,795 1 00 million years ago, 21 00:02:35,100 --> 00:02:38,831 massive forces shattered the super-continent of Gondwana 22 00:02:39,371 --> 00:02:42,704 and eventually a giant fragment floated off northwards, 23 00:02:43,075 --> 00:02:45,373 with a unique cargo of wildlife. 24 00:02:46,212 --> 00:02:48,237 Australia was born. 25 00:02:51,016 --> 00:02:52,745 This was an extraordinary world, 26 00:02:52,918 --> 00:02:55,284 lush, green and dripping with life. 27 00:02:56,088 --> 00:02:58,386 Today, there are still a few places in Australia 28 00:02:58,691 --> 00:03:01,023 where you can get a feel for that past. 29 00:03:05,397 --> 00:03:07,831 These are the rainforests of Tasmania. 30 00:03:13,572 --> 00:03:15,699 They're ancient, mysterious places 31 00:03:16,275 --> 00:03:22,009 and some of Australia's oddest animals live here, like the Tasmanian devil. 32 00:03:24,250 --> 00:03:25,217 They're scavengers, 33 00:03:25,384 --> 00:03:27,579 sort of antipodean hyaenas, 34 00:03:27,987 --> 00:03:31,821 and they use their powerful jaws to crush up every bit of a carcass. 35 00:03:33,292 --> 00:03:35,726 You may get a dozen or so around a dead Wallaby... 36 00:03:39,098 --> 00:03:42,693 ...and they find it hard to share, let alone be sociable. 37 00:03:44,270 --> 00:03:48,468 With such lethal teeth, manners like these can be very dangerous. 38 00:03:55,781 --> 00:03:57,510 Screaming at each other is safer, 39 00:03:57,983 --> 00:04:00,110 but better still is bum barging your neighbour 40 00:04:00,286 --> 00:04:02,720 with a few powerful blows from behind. 41 00:04:15,734 --> 00:04:18,669 This competitive spirit starts early in life. 42 00:04:18,938 --> 00:04:20,496 Devils are marsupials - 43 00:04:20,839 --> 00:04:23,000 their babies develop inside a pouch - 44 00:04:23,776 --> 00:04:25,710 and while this mother is jostling for a meal 45 00:04:25,878 --> 00:04:30,577 the young are tucked away inside doing much the same thing. 46 00:04:35,487 --> 00:04:37,512 Mothers produce about 20 embryos 47 00:04:37,690 --> 00:04:39,885 and they have to fight for just six teats, 48 00:04:40,059 --> 00:04:42,323 Competition is fierce and even the ones 49 00:04:42,494 --> 00:04:45,463 that survive still have to fight for a drink. 50 00:04:50,703 --> 00:04:53,433 Only three or four usually make it out of the pouch. 51 00:04:54,473 --> 00:04:57,237 By then the competitive spirit is well established - 52 00:04:57,409 --> 00:05:00,139 and will stay with them for the rest of their lives. 53 00:05:14,026 --> 00:05:16,859 Dense forests are not just confined to Tasmania - 54 00:05:17,463 --> 00:05:20,455 they spread right up the eastern coast of the continent because, 55 00:05:20,632 --> 00:05:22,964 soon after Australia became an island, 56 00:05:23,335 --> 00:05:26,168 its eastern side was buckled into mountains. 57 00:05:26,805 --> 00:05:29,831 These trap rain, blowing in from the ocean. 58 00:05:39,818 --> 00:05:43,151 So their lower slopes are covered in thick forest. 59 00:05:46,658 --> 00:05:49,354 Higher up, there are rugged peaks. 60 00:05:54,900 --> 00:05:59,234 And in the south, in winter, the rain falls as snow. 61 00:06:00,305 --> 00:06:04,867 These are the Australian Alps, covered in snow for months of the year. 62 00:06:05,778 --> 00:06:09,270 ln places it drifts up to 30 metres deep. 63 00:06:25,264 --> 00:06:28,131 lt's not something you'd expect to see in a land, 64 00:06:28,300 --> 00:06:30,200 which is mostly dusty and hot, 65 00:06:30,469 --> 00:06:34,405 but this weather can be ferocious and unpredictable... 66 00:06:37,376 --> 00:06:39,105 Sometimes there are blizzards. 67 00:06:46,552 --> 00:06:50,318 But even here, there are marsupials determined to make a living. 68 00:06:50,656 --> 00:06:55,525 This is a wombat, doubling up as a snowplough in an attempt to find food. 69 00:07:02,501 --> 00:07:04,435 Wombats are world-class diggers, 70 00:07:04,903 --> 00:07:08,999 and they use their strong front legs and snout to bulldoze through the snow, 71 00:07:09,208 --> 00:07:11,073 in search of grass beneath. 72 00:07:15,314 --> 00:07:16,713 They're normally nocturnal, 73 00:07:17,182 --> 00:07:19,844 but now it's far too cold to come out at night, 74 00:07:20,119 --> 00:07:24,180 so they forage during the day, even in the worst of the weather. 75 00:07:34,233 --> 00:07:35,598 lt's a tough place 76 00:07:35,767 --> 00:07:41,034 but there are other marsupials up here as well - dainty little wallabies. 77 00:07:47,379 --> 00:07:48,846 Surprisingly, both the wallaby 78 00:07:49,014 --> 00:07:52,211 and the wombat have young families in these conditions, 79 00:07:52,551 --> 00:07:54,109 in the depths of winter. 80 00:07:55,287 --> 00:07:56,845 But there's a good reason for this - 81 00:07:57,489 --> 00:07:59,650 these joeys will emerge in spring, 82 00:07:59,858 --> 00:08:02,622 just in time to feed on the new green shoots. 83 00:08:06,532 --> 00:08:10,525 Meantime, a centrally heated pouch is the warmest place to be. 84 00:08:15,707 --> 00:08:17,937 Even the world's weirdest mammal, the platypus, 85 00:08:18,110 --> 00:08:22,137 makes a living in the icy waters of these mountains. 86 00:08:27,619 --> 00:08:30,349 Uniquely Australian, it has a duck's bill, 87 00:08:30,756 --> 00:08:34,192 an otter's tail and webbed feet with claws. 88 00:08:34,960 --> 00:08:39,863 Males have poisonous spurs and females lay eggs, like birds - 89 00:08:40,632 --> 00:08:44,591 so it's hardly surprising that early reports of them were treated as hoaxes. 90 00:08:46,705 --> 00:08:50,664 lt's actually a monotreme, a typically Australian group of mammals. 91 00:08:55,447 --> 00:08:58,177 That weird looking bill is highly specialised, 92 00:08:58,584 --> 00:08:59,642 with tiny sensors 93 00:08:59,818 --> 00:09:03,845 to detect the minute electrical signals from the muscles of its prey. 94 00:09:04,923 --> 00:09:09,724 So sophisticated, the platypus can swim with its eyes and ears closed. 95 00:09:15,267 --> 00:09:17,326 By swinging its head from side to side, 96 00:09:17,803 --> 00:09:20,601 it builds up a radar-like map of the stream, 97 00:09:20,872 --> 00:09:23,636 pinpointing the shrimp and worms it likes to eat. 98 00:09:33,285 --> 00:09:38,154 lt's a very adaptable animal, making its home in forest streams like these... 99 00:09:38,757 --> 00:09:41,487 all the way up the east coast of Australia... 100 00:09:46,398 --> 00:09:48,161 ...from the snowy mountains of the south, 101 00:09:48,934 --> 00:09:52,199 right up to these tropical rainforests in the north. 102 00:10:02,347 --> 00:10:04,076 Like the Tasmanian forests, 103 00:10:04,483 --> 00:10:08,943 these are also ancient and have been here since before Australia was born. 104 00:10:10,656 --> 00:10:13,147 The land they cover today is relatively small, 105 00:10:13,525 --> 00:10:16,119 just one thousandth of the continent, 106 00:10:17,229 --> 00:10:20,164 but they have just about the richest mixture of wildlife 107 00:10:20,499 --> 00:10:23,161 of any of Australia's environments. 108 00:10:44,356 --> 00:10:46,153 lt's here, of all places, 109 00:10:46,792 --> 00:10:50,228 you can see what a truly strange place Australia is - 110 00:10:50,896 --> 00:10:55,094 here more than anywhere, you see how its original cargo of wildlife 111 00:10:55,400 --> 00:10:59,234 has evolved into such a variety of unique species. 112 00:11:10,482 --> 00:11:13,781 lmprobable giants, like this flightless Cassowary. 113 00:11:21,693 --> 00:11:26,995 And marsupials, in every shape and form, including the possums. 114 00:11:29,167 --> 00:11:31,761 One of the most striking is the striped possum, 115 00:11:31,937 --> 00:11:35,703 which scampers over tree trunks looking for grubs and nectar. 116 00:11:37,776 --> 00:11:41,303 There is no better source of nectar than the bumpy satin ash - 117 00:11:41,480 --> 00:11:45,541 covered in thousands of tiny blossoms growing straight from the trunk. 118 00:11:46,518 --> 00:11:47,917 The possum gets a sticky meal 119 00:11:48,387 --> 00:11:52,881 and it also picks up pollen on its fur, transferring it from tree to tree. 120 00:12:03,902 --> 00:12:06,530 There are 26 species of possum in Australia 121 00:12:06,705 --> 00:12:09,902 and almost half of them live in these rainforests. 122 00:12:11,543 --> 00:12:14,307 Some have found ingenious ways to move around. 123 00:12:20,886 --> 00:12:22,945 This is a sugar glider... 124 00:12:38,270 --> 00:12:42,036 Flying through the air - or perhaps just falling with style - 125 00:12:42,441 --> 00:12:45,171 they use their own built in sky diving suits, 126 00:12:45,343 --> 00:12:49,370 to glide from tree to tree for up to fifty metres. 127 00:12:51,149 --> 00:12:54,585 They can steer, even change direction by ninety degrees, 128 00:12:54,753 --> 00:12:59,781 by adjusting their flaps of skin, and using their tails as a rudder. 129 00:13:10,802 --> 00:13:11,928 When it's time to land, 130 00:13:12,237 --> 00:13:15,968 they just lower their flaps and put out their landing gear. 131 00:13:19,077 --> 00:13:21,011 Although touchdown could be better! 132 00:13:25,283 --> 00:13:28,218 But why did some possums evolve to glide? 133 00:13:31,656 --> 00:13:35,854 Soon after Australia became an island, its climate started to dry out. 134 00:13:38,063 --> 00:13:40,930 The thick, tangled forest that had covered most of Australia 135 00:13:41,099 --> 00:13:45,365 for so long began to thin out into open woodland. 136 00:13:51,576 --> 00:13:55,808 lt was a change that stamped the character of the Australian bush we know today. 137 00:13:56,481 --> 00:14:00,679 The lush rainforest was replaced by Eucalpts, or gum trees. 138 00:14:01,786 --> 00:14:03,583 With trees now further apart, 139 00:14:03,822 --> 00:14:06,848 some possums evolved to glide across the gaps. 140 00:14:07,826 --> 00:14:11,455 And there was now space for other types of travel too. 141 00:14:16,868 --> 00:14:20,133 Kangaroos evolved in woodlands just like these. 142 00:14:22,807 --> 00:14:24,968 You need room to bounce around like this, 143 00:14:25,143 --> 00:14:28,340 a uniquely Australian solution to budget travel. 144 00:14:34,085 --> 00:14:35,279 At certain speeds, 145 00:14:35,453 --> 00:14:39,549 a hopping kangaroo is more efficient than any horse or antelope. 146 00:14:40,959 --> 00:14:43,359 They live in family groups called mobs, 147 00:14:43,662 --> 00:14:46,529 and females can be impressive breeding machines - 148 00:14:47,198 --> 00:14:50,326 there are over fifty million kangaroos in Australia, 149 00:14:50,936 --> 00:14:53,234 more than twice the human population. 150 00:14:59,878 --> 00:15:02,779 Having such a successful design is all very well, 151 00:15:02,981 --> 00:15:04,676 but you need to know how to use it. 152 00:15:05,383 --> 00:15:06,975 Just three days out of the pouch, 153 00:15:07,152 --> 00:15:10,417 this Joey has more than just a spring in his step. 154 00:15:25,136 --> 00:15:29,436 Learning to get about on two supercharged pogo sticks is no mean feat. 155 00:15:51,262 --> 00:15:54,891 That was exhausting - time for a nap. 156 00:16:00,005 --> 00:16:03,338 But as you grow older, fitting those legs inside isn't easy 157 00:16:03,508 --> 00:16:07,604 and within two months he'll be out of the pouch for good. 158 00:16:10,548 --> 00:16:11,810 Up in the gum trees, 159 00:16:11,983 --> 00:16:16,613 there's another marsupial with a less energetic approach to life... 160 00:16:23,161 --> 00:16:25,959 lt has the laid back Aussie love for leisure. 161 00:16:28,533 --> 00:16:32,526 This koala is putting his back into taking it easy. 162 00:16:36,007 --> 00:16:40,341 Koalas eat gum leaves, which are full of toxins and hard to digest. 163 00:16:40,912 --> 00:16:45,940 To survive on a diet like this they've turned napping into a national sport. 164 00:16:46,418 --> 00:16:48,113 Of course, it looks like dozing, 165 00:16:48,286 --> 00:16:52,382 but these guys are working really hard to digest their meal. 166 00:16:54,626 --> 00:16:57,959 But at one time of the year this all changes... 167 00:16:58,363 --> 00:17:01,730 lt's spring and the males want to mate. 168 00:17:04,402 --> 00:17:07,701 To kick-start the season, they begin by calling. 169 00:17:08,039 --> 00:17:12,840 But if your date is almost comatose, that may not be enough. 170 00:17:24,489 --> 00:17:28,653 For some of the older males, this is already too much like hard work. 171 00:17:28,827 --> 00:17:31,318 They can't keep the mood going for long. 172 00:17:38,169 --> 00:17:42,469 For those who can gather enough energy, the chase is on. 173 00:17:44,642 --> 00:17:48,976 But this female, with a baby on her back, is not ready to mate... 174 00:17:49,214 --> 00:17:52,479 For a koala, this is really getting a move on. 175 00:17:56,521 --> 00:17:59,513 But males can be very determined. 176 00:18:06,164 --> 00:18:08,928 Gentlemanly courtship is not his style. 177 00:18:11,169 --> 00:18:13,865 Nor is the female willing to give in. 178 00:18:17,041 --> 00:18:23,002 ln fact his only skill seems to be the ability to turn a drama into a crisis... 179 00:18:35,760 --> 00:18:37,887 The baby is now in serious danger 180 00:18:38,296 --> 00:18:41,129 and in the scramble gets separated from its mother. 181 00:18:57,015 --> 00:18:58,482 But it gets even worse. 182 00:18:58,783 --> 00:19:03,152 ln the confusion the youngster ends up dangling from the bottom of the male. 183 00:19:07,158 --> 00:19:10,218 This farce could easily turn into tragedy. 184 00:19:16,501 --> 00:19:18,366 The male has bungled the whole episode. 185 00:19:18,937 --> 00:19:19,835 lt's time to exit, 186 00:19:20,004 --> 00:19:24,532 but as he slams into reverse, he takes the baby with him. 187 00:19:35,453 --> 00:19:39,014 Escape at last, but the baby isn't out of danger yet. 188 00:19:39,591 --> 00:19:42,583 Young koalas depend on their mothers until a year old... 189 00:19:44,162 --> 00:19:47,461 and this one is too small to survive on his own. 190 00:19:52,237 --> 00:19:56,731 Encouraged by her calls, though, he manages to sprint the last few metres - 191 00:19:57,075 --> 00:19:58,906 back into her arms. 192 00:20:04,582 --> 00:20:06,072 Now he's safe. 193 00:20:16,494 --> 00:20:20,157 Raising babies, with or without rampaging males in the neighbourhood, 194 00:20:20,498 --> 00:20:23,262 is not easy in these Eucalypt woodlands. 195 00:20:23,568 --> 00:20:28,005 They're tough places, dusty and dry, without a lot of food. 196 00:20:31,576 --> 00:20:34,443 ...especially with mouths like these to feed. 197 00:20:40,685 --> 00:20:41,982 This is a kookaburra 198 00:20:43,688 --> 00:20:46,122 and these chicks are demanding customers. 199 00:20:46,491 --> 00:20:48,686 They want round the clock room service. 200 00:20:50,528 --> 00:20:53,122 lt's a problem for parents to provide this on their own 201 00:20:53,298 --> 00:20:56,324 so they enlist the help of last year's brood. 202 00:20:56,501 --> 00:20:58,799 lt's a sort of Kookaburra Catering Corps, 203 00:20:59,270 --> 00:21:01,500 with a bit of work experience thrown in. 204 00:21:02,073 --> 00:21:04,667 They'll be learning all about bringing up chicks. 205 00:21:05,810 --> 00:21:08,574 Kookaburras are the largest kingfishers in the world - 206 00:21:09,147 --> 00:21:12,275 but being Australian, they don't always catch fish 207 00:21:12,450 --> 00:21:14,918 and they don't always live near rivers. 208 00:21:16,821 --> 00:21:20,552 To keep the brood well fed, they catch everything they can find... 209 00:21:20,725 --> 00:21:23,785 spiders, snakes, sometimes even small mammals - 210 00:21:23,962 --> 00:21:26,362 anything to keep the noise down. 211 00:21:37,675 --> 00:21:41,167 With the entire family working together on constant dinner duty, 212 00:21:41,512 --> 00:21:44,811 they can deliver a conveyor belt of food round the clock. 213 00:21:46,317 --> 00:21:48,376 But it seems the faster they shovel it in, 214 00:21:48,853 --> 00:21:51,048 the louder the babies cry. 215 00:22:06,104 --> 00:22:09,870 Now and then, though, a big mouthful of lizard seems to do the trick. 216 00:22:18,950 --> 00:22:21,783 These parched woodlands aren't just tough places to live in 217 00:22:21,953 --> 00:22:23,580 and bring up a family - 218 00:22:23,821 --> 00:22:25,220 they're dangerous as well. 219 00:22:32,797 --> 00:22:35,459 They're tinder dry and easily ignite. 220 00:22:38,336 --> 00:22:41,601 When a spark hits the volatile oils in their leaves and bark, 221 00:22:41,773 --> 00:22:44,071 gum trees burst into flame. 222 00:22:44,409 --> 00:22:47,173 Within minutes the woodland is a fireball. 223 00:22:51,416 --> 00:22:54,715 Animals that can move fast get out quick. 224 00:23:10,301 --> 00:23:12,599 lf the wind gets up it can fan the blaze, 225 00:23:12,770 --> 00:23:16,137 causing crown-fires that race through the treetops. 226 00:23:26,617 --> 00:23:30,178 And afterwards, Armageddon. 227 00:23:41,165 --> 00:23:45,625 The morning after there may be a few dead insects around, the odd shoot, 228 00:23:45,937 --> 00:23:49,634 but any animals that survived will have to move on. 229 00:23:55,079 --> 00:23:57,547 And they may have a long way to go. 230 00:23:57,882 --> 00:24:01,477 Hundreds of kilometres of woodland can disappear in days. 231 00:24:01,886 --> 00:24:07,188 Three million hectares a year are incinerated by fires like this. 232 00:24:15,099 --> 00:24:18,398 But then, something extraordinary happens. 233 00:24:19,103 --> 00:24:22,402 Many gum trees have evolved to survive bushfires, 234 00:24:24,375 --> 00:24:27,173 and some have energy stores beneath their bark, 235 00:24:27,345 --> 00:24:30,212 which allow them to burst back into life. 236 00:24:30,581 --> 00:24:31,673 Within a week or two 237 00:24:32,016 --> 00:24:35,543 their trunks are covered in dazzling green foliage. 238 00:24:44,562 --> 00:24:47,929 The drying out of Australia's climate over millions of years 239 00:24:48,332 --> 00:24:50,960 not only had a major effect on its forests, 240 00:24:51,269 --> 00:24:54,170 but also had a dramatic effect on its rivers. 241 00:24:56,374 --> 00:24:59,207 Long ago, Australia had a network of mighty rivers 242 00:24:59,377 --> 00:25:01,811 stretching right into the heart of the continent. 243 00:25:02,346 --> 00:25:05,975 But when the climate dried, they dried up too. 244 00:25:06,284 --> 00:25:10,482 Today, the largest river system left is the Murray Darling. 245 00:25:11,722 --> 00:25:13,519 And here it is 246 00:25:13,758 --> 00:25:16,352 barely wider than the average road. 247 00:25:19,830 --> 00:25:20,854 lt's extraordinary 248 00:25:21,098 --> 00:25:25,558 that a 2,500 kilometre long river should be so narrow... 249 00:25:25,870 --> 00:25:28,304 And this is in full flood. 250 00:25:35,179 --> 00:25:37,409 Even in a year, less water flows down 251 00:25:37,582 --> 00:25:41,951 the Murray Darling than down the Amazon in a single day. 252 00:25:52,363 --> 00:25:55,025 Most of Australia's rivers are even smaller. 253 00:25:55,566 --> 00:25:58,160 Many are steams that dry up for part of the year, 254 00:25:58,336 --> 00:26:02,295 others are creeks that haven't seen water for years. 255 00:26:14,252 --> 00:26:18,746 But in many riverbeds water remains in pools called billabongs. 256 00:26:19,290 --> 00:26:20,917 ln Australia's parched landscape 257 00:26:21,092 --> 00:26:23,356 these stand out as irresistible lures, 258 00:26:23,694 --> 00:26:26,458 drawing in wildlife from every direction. 259 00:26:38,409 --> 00:26:40,809 Billabongs are vital for life in the outback 260 00:26:41,112 --> 00:26:44,707 and many animals live or die by their skills at finding them. 261 00:26:46,851 --> 00:26:51,379 None arrive in greater numbers than corella parrots. 262 00:26:58,062 --> 00:27:00,690 These turn up in their thousands, 263 00:27:01,632 --> 00:27:05,033 in flocks so huge that early explorers in search of water 264 00:27:05,202 --> 00:27:08,228 learnt to look for them on the horizon. 265 00:27:11,609 --> 00:27:14,976 ln this early evening rush hour, they're joined by budgies - 266 00:27:15,613 --> 00:27:19,447 tough little nomads, who will travel a long way for water. 267 00:27:38,536 --> 00:27:41,903 By the end of the day thousands of birds are gathered here, 268 00:27:42,273 --> 00:27:46,505 and every available tree seems packed with budgies and corellas. 269 00:28:01,292 --> 00:28:03,487 Most animals that live in the parched outback 270 00:28:03,661 --> 00:28:06,027 get at least some water from their food. 271 00:28:06,197 --> 00:28:09,530 But corellas and budgies eat seeds, which are very dry, 272 00:28:09,934 --> 00:28:12,027 so they need to drink every day. 273 00:28:28,853 --> 00:28:33,881 Kangaroos can survive for longer without water, but rarely stray far from it. 274 00:28:41,499 --> 00:28:46,300 On the other hand, emus may have followed a trail for over a hundred kilometres. 275 00:28:46,670 --> 00:28:50,606 They use cues like distant clouds or the sound of far off thunder 276 00:28:50,775 --> 00:28:52,868 to help them find water. 277 00:28:53,944 --> 00:28:59,109 And it's not just vital for daily life - animals need it for breeding as well. 278 00:29:00,651 --> 00:29:04,951 Because rain is so unpredictable kangaroos have to breed when they can and, 279 00:29:05,122 --> 00:29:08,990 when there's water about, females move into mass production. 280 00:29:09,160 --> 00:29:10,855 She may be suckling an older Joey, 281 00:29:11,028 --> 00:29:15,294 with another one in the pouch and probably an embryo inside her as well. 282 00:29:20,271 --> 00:29:22,068 Budgies too make the most of it. 283 00:29:22,706 --> 00:29:27,040 Where they find water they can set up home and raise a family in an instant. 284 00:29:27,311 --> 00:29:30,542 But they have to put up with some rather annoying neighbours. 285 00:29:33,417 --> 00:29:37,285 All the activity at this budgie household seems too much for the corellas. 286 00:29:37,455 --> 00:29:40,788 They are intelligent birds, but they're also busybodies 287 00:29:41,125 --> 00:29:44,617 and enjoy sticking their beaks into other people's business. 288 00:29:46,330 --> 00:29:49,094 For the budgies, they're the neighbours from hell. 289 00:29:55,573 --> 00:29:57,234 The corellas are just being nosey, 290 00:29:57,641 --> 00:30:01,168 but it is probably best for the budgie chicks to stay in their hole. 291 00:30:07,885 --> 00:30:09,580 These are playful birds 292 00:30:09,887 --> 00:30:13,983 and after a few drinks at the billabong, they like a bit of fun. 293 00:30:16,727 --> 00:30:20,185 Fooling around like this helps to strengthen their relationships... 294 00:30:24,802 --> 00:30:27,032 ...but some of it's just showing off. 295 00:30:44,822 --> 00:30:48,087 While the water lasts they make the most of this time off, 296 00:30:48,359 --> 00:30:50,657 in the cooler evening light. 297 00:31:06,277 --> 00:31:09,110 Although much of Australia has very little water, 298 00:31:09,580 --> 00:31:13,016 there's one area that's awash with it. 299 00:31:13,584 --> 00:31:14,915 Since becoming an island, 300 00:31:15,185 --> 00:31:19,281 Australia has been drifting north at about five centimetres a year, 301 00:31:19,657 --> 00:31:22,091 so its top end is now in the tropics, 302 00:31:22,393 --> 00:31:25,089 right in the path of the tropical monsoon. 303 00:31:26,330 --> 00:31:30,232 This is one of the most powerful weather systems on the planet. 304 00:31:40,311 --> 00:31:42,905 lt lasts for only a few months each year, 305 00:31:43,247 --> 00:31:48,082 but while it does northern Australia becomes a very different place. 306 00:31:48,285 --> 00:31:50,116 lt has a dramatic wet season. 307 00:31:54,625 --> 00:31:55,819 For a short time, 308 00:31:56,093 --> 00:32:00,553 rain falls so hard that rivers turn into raging torrents. 309 00:32:12,910 --> 00:32:16,971 Where they burst out of their gorges they flood out onto open plains, 310 00:32:17,348 --> 00:32:20,749 creating some of the world's largest tropical wetlands. 311 00:32:25,289 --> 00:32:29,055 The most famous of these is called Kakadu. 312 00:32:32,529 --> 00:32:36,556 Every year, huge numbers of birds arrive to feed and breed. 313 00:32:37,067 --> 00:32:41,436 Two million magpie geese alone jostle for space with ducks, herons, 314 00:32:41,672 --> 00:32:45,665 ibis and other water birds, some feeding on the flooded grass, 315 00:32:46,076 --> 00:32:48,806 others on shrimps and small fish. 316 00:32:59,957 --> 00:33:02,551 But birds aren't the only animals here... 317 00:33:06,430 --> 00:33:09,092 ln the quiet streams on the edge of the swamp are residents 318 00:33:09,266 --> 00:33:12,030 who live here all year round. 319 00:33:13,604 --> 00:33:18,007 This strangely prehistoric looking reptile is an amphibious lizard 320 00:33:18,175 --> 00:33:20,507 called Merton's water monitor. 321 00:33:25,716 --> 00:33:29,618 They're graceful swimmers, spending some of their time completely submerged, 322 00:33:29,787 --> 00:33:34,281 propelled by a long, powerful tail, which doubles up as a rudder. 323 00:33:40,230 --> 00:33:42,755 They're scavengers and, even underwater, 324 00:33:42,933 --> 00:33:46,198 they can 'taste' the scent of rotting food. 325 00:34:09,793 --> 00:34:12,956 Finally, it finds the meal it's been looking for - 326 00:34:13,630 --> 00:34:15,723 a dead fish. 327 00:34:21,705 --> 00:34:24,037 There are other reptiles here, too - 328 00:34:24,274 --> 00:34:27,971 freshwater crocodiles, also uniquely Australian. 329 00:34:29,346 --> 00:34:32,713 These are daintier cousins of the giant saltwater crocs 330 00:34:32,916 --> 00:34:36,477 and they feed on smaller prey, like fish and crustaceans. 331 00:34:43,427 --> 00:34:44,917 This is boom time... 332 00:34:45,295 --> 00:34:50,858 but it won't be long before the monsoon ends and the blazing sun takes over again. 333 00:35:02,112 --> 00:35:07,744 As the water evaporates, the swamp congeals into an ocean of sticky mud. 334 00:35:08,886 --> 00:35:13,482 On the margins of Kakadu the streams dwindle into pools of sludge. 335 00:35:14,124 --> 00:35:19,357 The monitors can move back on land, but these freshies rely on water to keep cool. 336 00:35:19,663 --> 00:35:23,599 Their situation is beginning to look increasingly sticky. 337 00:35:25,869 --> 00:35:30,829 Before they get stuck fast, these crocs must do something, and quickly. 338 00:35:37,681 --> 00:35:41,447 As the evening heat dies down they slide to the edge of the pool. 339 00:35:41,885 --> 00:35:47,050 Their only chance of surviving is to travel over land in search of more water. 340 00:35:49,560 --> 00:35:52,393 They'll need to find it before sunrise. 341 00:35:57,601 --> 00:36:00,263 lnstead of the normal crocodile 'belly crawl' 342 00:36:00,571 --> 00:36:04,098 they march overland with this unusual ''high walk''. 343 00:36:05,943 --> 00:36:09,879 lt's the fastest way to travel if they're going to find water by dawn. 344 00:36:15,752 --> 00:36:19,188 When the sun comes up, they're in real danger of overheating - 345 00:36:19,590 --> 00:36:22,320 but these freshies have one last trick. 346 00:36:28,165 --> 00:36:31,566 With a unique gallop they make an Olympic dash, 347 00:36:31,869 --> 00:36:34,838 and become the fastest crocodiles in the world. 348 00:36:46,984 --> 00:36:48,076 With any luck, 349 00:36:48,318 --> 00:36:52,379 a deep pool like this will survive until the monsoon returns. 350 00:37:00,564 --> 00:37:02,225 But most of the streams and pools 351 00:37:02,499 --> 00:37:06,595 will have all their water sucked out of them by the burning tropical sun. 352 00:37:13,744 --> 00:37:17,236 Throughout its long history, Australia has dried out so much 353 00:37:17,447 --> 00:37:19,608 that about half the continent is now desert - 354 00:37:20,417 --> 00:37:25,650 in places so arid and alien, it looks more like the surface of Mars. 355 00:37:44,107 --> 00:37:49,067 ln the harshest areas, there are vast lakes of dry salt. 356 00:37:56,920 --> 00:38:01,823 With almost no vegetation, the bones of the continent are laid bare. 357 00:38:04,061 --> 00:38:05,858 Like a gigantic ribcage, 358 00:38:06,029 --> 00:38:09,658 these parallel sand dunes stretch for hundreds of kilometres. 359 00:38:14,204 --> 00:38:19,836 And at the heart of the desert, Uluru - one of the world's largest rocks, 360 00:38:21,378 --> 00:38:23,539 and this is just the tip. 361 00:38:23,714 --> 00:38:27,081 The rest extends six kilometres below ground. 362 00:38:28,986 --> 00:38:31,682 ln such a dry landscape, it seems bizarre 363 00:38:31,855 --> 00:38:37,088 that Uluru was actually weathered into shape by millions of years of rain. 364 00:38:41,264 --> 00:38:44,722 At first glance there doesn't seem much sign of life in the desert. 365 00:38:46,203 --> 00:38:47,135 But during the day, 366 00:38:47,304 --> 00:38:49,864 most sensible Australians stay out of the sun... 367 00:38:50,674 --> 00:38:53,541 and the planigale is no exception. 368 00:38:53,777 --> 00:38:58,441 lt's one of Australia's smallest marsupials - and one of the toughest. 369 00:38:58,749 --> 00:39:02,845 lt needs to be - most of its meals are larger than it. 370 00:39:08,558 --> 00:39:12,255 Dwarfed even by this moth, the planigale doesn't give in. 371 00:39:12,629 --> 00:39:14,324 With true outback grit, 372 00:39:14,698 --> 00:39:17,690 it tries to wrestle this oversize meal to the ground... 373 00:39:19,202 --> 00:39:21,534 ...and fails again. 374 00:39:22,806 --> 00:39:23,898 ln these underground cracks 375 00:39:24,074 --> 00:39:27,566 it's almost fifteen degrees cooler than out in the sun, 376 00:39:28,078 --> 00:39:31,775 so the planigale can hunt for a smaller meal in comfort. 377 00:39:37,954 --> 00:39:39,819 Or so he thinks... 378 00:39:44,528 --> 00:39:46,359 This is no time to relax, 379 00:39:46,563 --> 00:39:51,694 when above you is the world's deadliest snake... the inland taipan. 380 00:40:00,277 --> 00:40:02,507 This snake scares even Australians. 381 00:40:02,679 --> 00:40:04,476 lt's loaded with venom - 382 00:40:04,948 --> 00:40:10,682 enough to kill thousands of planigales and you or me, in minutes. 383 00:40:11,888 --> 00:40:14,356 Now being small has its advantages. 384 00:40:16,326 --> 00:40:20,558 With a specially flattened head it can squeeze into tiny crevices. 385 00:40:28,738 --> 00:40:33,198 Even the world's most venomous snake can't always get a meal. 386 00:40:34,311 --> 00:40:37,075 The Australian desert is full of deadly snakes. 387 00:40:37,414 --> 00:40:39,974 ln fact, all sorts of reptiles flourish here, 388 00:40:40,150 --> 00:40:41,913 especially lizards. 389 00:40:43,553 --> 00:40:45,714 Australia has more than any other continent 390 00:40:46,089 --> 00:40:49,991 and in the desert a single sand dune can support forty species - 391 00:40:50,961 --> 00:40:53,828 this really is the land of the lizard. 392 00:40:54,231 --> 00:40:57,029 The largest are more than a metre long. 393 00:40:58,735 --> 00:41:04,332 This is a sand goanna, also known as a racehorse goanna for obvious reason. 394 00:41:16,219 --> 00:41:20,849 Lizards are much more successful here than mammals because they need less food. 395 00:41:23,927 --> 00:41:28,489 Meals can be scarce and goannas will eat virtually anything they can catch... 396 00:41:29,432 --> 00:41:31,366 Even scorpions. 397 00:41:59,329 --> 00:42:03,595 Goannas do get stung, but they seem to be immune to the poison. 398 00:42:04,768 --> 00:42:09,535 lt may not be much, but this could be its last meal for weeks. 399 00:42:11,641 --> 00:42:14,474 Animals don't come much tougher than the adult goanna, 400 00:42:14,711 --> 00:42:16,872 but their eggs are more vulnerable. 401 00:42:17,047 --> 00:42:19,948 They need protection from the harsh desert climate 402 00:42:20,116 --> 00:42:23,779 and termite mounds make perfect incubators. 403 00:42:25,956 --> 00:42:28,390 These eggs were laid about nine months ago 404 00:42:28,558 --> 00:42:30,822 and they're now ready to hatch. 405 00:42:44,874 --> 00:42:47,399 Fully formed miniature adults emerge. 406 00:42:57,854 --> 00:43:00,118 The termite mounds gave perfect protection 407 00:43:00,390 --> 00:43:02,950 but now they're a barrier to the outside world, 408 00:43:03,126 --> 00:43:05,617 and these babies need to get out. 409 00:43:12,602 --> 00:43:14,467 The walls can be rock hard. 410 00:43:23,013 --> 00:43:26,449 But the youngsters are already as determined as adults. 411 00:43:32,522 --> 00:43:34,387 One by one, they clamber out 412 00:43:34,557 --> 00:43:38,049 to enter one of the toughest habitats on earth. 413 00:43:44,067 --> 00:43:47,764 Over its long history, Australia has dried out so much, 414 00:43:48,271 --> 00:43:53,937 that in places its desert heart has now expanded right up to the coast. 415 00:44:06,122 --> 00:44:07,555 Millions of years of drying 416 00:44:07,724 --> 00:44:10,659 has had an enormous impact on the character of Australia 417 00:44:11,361 --> 00:44:15,127 but one further event put the finishing touches to its shape. 418 00:44:16,533 --> 00:44:20,230 Just ten thousand years ago, at the end of the ice age, 419 00:44:20,570 --> 00:44:22,868 sea levels around the world rose. 420 00:44:23,239 --> 00:44:28,871 Australia's coastline was flooded, creating thousands of beautiful islands. 421 00:44:35,552 --> 00:44:39,249 This flooding also helped shape the world's largest living structure, 422 00:44:39,789 --> 00:44:42,053 the Great Barrier Reef. 423 00:44:42,859 --> 00:44:44,588 This reef was once dry land - 424 00:44:44,894 --> 00:44:47,727 aborigines might even have hunted kangaroos here. 425 00:44:48,331 --> 00:44:50,697 Now, at over two thousand kilometres long, 426 00:44:51,134 --> 00:44:54,763 it's the greatest coral complex to have ever existed. 427 00:44:56,506 --> 00:45:00,533 lt's hard to imagine a more colourful and vibrant contrast to the dry, 428 00:45:00,710 --> 00:45:02,302 crusty old continent. 429 00:45:09,219 --> 00:45:12,746 Over four hundred different corals in every shape and size, 430 00:45:12,922 --> 00:45:16,323 support more than two thousand species of fish. 431 00:45:19,696 --> 00:45:21,630 And for just a few days in spring, 432 00:45:21,931 --> 00:45:25,389 the reef bursts into a special frenzy of activity. 433 00:45:33,209 --> 00:45:37,077 With precision timing, using cues from the moon and the tides, 434 00:45:37,414 --> 00:45:39,507 many fish begin to breed. 435 00:45:40,383 --> 00:45:42,283 Thousands of them condense their courtship 436 00:45:42,452 --> 00:45:46,320 and spawning into just a few minutes of frantic fertilisation. 437 00:46:01,905 --> 00:46:03,634 But, on just a few nights each year, 438 00:46:04,040 --> 00:46:06,702 an even more remarkable event takes place... 439 00:46:08,011 --> 00:46:14,678 On certain tides, just after the full moon, the reef itself begins to erupt. 440 00:46:25,295 --> 00:46:27,286 Two thousand kilometres of coral 441 00:46:27,464 --> 00:46:33,494 takes part in a synchronised release of eggs and sperm, in vast quantities. 442 00:46:41,077 --> 00:46:44,046 No one knows quite how so many billions of eggs 443 00:46:44,280 --> 00:46:48,876 are timed to release on the same night, so precisely. 444 00:46:59,162 --> 00:47:02,757 lt's the biggest synchronized breeding event on the planet. 445 00:47:23,286 --> 00:47:25,686 lt seems extraordinary that Australia, 446 00:47:25,955 --> 00:47:29,083 the harshest, driest inhabited continent on earth, 447 00:47:29,459 --> 00:47:33,896 has also produced such a colossal, vibrant, growing, structure. 448 00:47:35,732 --> 00:47:37,927 But from the moment Australia became an island, 449 00:47:38,268 --> 00:47:43,638 its isolation and unique history have shaped it into this continent of extremes. 450 00:47:43,907 --> 00:47:47,741 Australia's story has created a land of fantastic diversity - 451 00:47:48,177 --> 00:47:50,111 the weirdest mix of animals and plants, 452 00:47:50,480 --> 00:47:54,974 living in some of the toughest but most beautiful landscapes imaginable. 453 00:48:04,327 --> 00:48:09,264 This really is the strangest continent on earth.