1 00:00:36,000 --> 00:00:37,480 North Africa. 2 00:00:55,880 --> 00:00:59,160 High in Morocco's Atlas Mountains, 3 00:00:59,160 --> 00:01:03,200 Barbary macaques shiver in the icy cedars. 4 00:01:12,800 --> 00:01:15,720 The ancestors of these monkeys fled here 5 00:01:15,720 --> 00:01:19,360 from a disaster that overwhelmed their homeland. 6 00:01:21,600 --> 00:01:25,160 Now, trapped in this isolated corner of Africa, 7 00:01:25,160 --> 00:01:28,560 there's no going back to the land farther south. 8 00:01:31,720 --> 00:01:33,960 Even in this snowy refuge, 9 00:01:33,960 --> 00:01:35,120 there's a reminder 10 00:01:35,120 --> 00:01:36,520 of what drove them here. 11 00:01:42,800 --> 00:01:46,400 The unbridled power of the African sun. 12 00:01:54,120 --> 00:01:56,640 Under its intense gaze, 13 00:01:56,640 --> 00:01:58,560 the snow can't last for long. 14 00:02:05,400 --> 00:02:09,280 Melt water should bring life to the lowlands. 15 00:02:12,560 --> 00:02:15,760 Hundreds of torrents cascade southwards. 16 00:02:18,040 --> 00:02:21,760 But each is flowing towards extinction. 17 00:02:26,600 --> 00:02:29,680 Just 200 miles south of the mountains, 18 00:02:29,680 --> 00:02:32,120 the rivers are vaporised. 19 00:02:38,520 --> 00:02:41,600 Life has been burnt off the land. 20 00:02:50,000 --> 00:02:54,160 This was the apocalypse from which the Barbary macaques fled. 21 00:02:55,920 --> 00:02:58,800 The sudden and unstoppable advance 22 00:02:58,800 --> 00:03:01,840 of the greatest desert on the planet. 23 00:03:14,480 --> 00:03:17,560 The Sahara transformed North Africa. 24 00:03:19,320 --> 00:03:21,080 Today, it covers an area 25 00:03:21,080 --> 00:03:23,360 the size of the United States. 26 00:03:23,360 --> 00:03:26,360 One-third of the entire African continent. 27 00:03:32,480 --> 00:03:36,320 This is one of the hottest places on Earth. 28 00:03:44,280 --> 00:03:46,200 The merciless sun, 29 00:03:46,200 --> 00:03:50,440 a colossal 15-million-degree nuclear reactor, 30 00:03:50,440 --> 00:03:53,200 blasted life from the surface of the land. 31 00:03:57,400 --> 00:03:59,680 It still wreaks havoc. 32 00:03:59,680 --> 00:04:03,120 A faint breath of wind can be the beginning of disaster. 33 00:04:49,040 --> 00:04:53,160 Nomads tell of entire villages being engulfed... 34 00:04:54,720 --> 00:04:56,760 ..camel trains disappearing, 35 00:04:56,760 --> 00:05:01,000 and people buried alive inside their tents. 36 00:05:50,680 --> 00:05:55,280 A sandstorm can be 1,000 miles across. 37 00:05:58,600 --> 00:06:04,000 It seems miraculous that anything can survive such devastation. 38 00:06:07,720 --> 00:06:12,400 The Saharan apocalypse wiped out many creatures, 39 00:06:12,400 --> 00:06:15,160 but, today, some still cling on, 40 00:06:15,160 --> 00:06:18,440 in the lands around the margins of the great desert. 41 00:06:23,040 --> 00:06:24,480 It's very dry here. 42 00:06:25,640 --> 00:06:28,800 Some years, the rains fail entirely. 43 00:06:38,000 --> 00:06:41,040 A lone Grevy's zebra. 44 00:06:43,240 --> 00:06:46,080 He weighs close to half a tonne, 45 00:06:46,080 --> 00:06:49,320 and could go for three days without drinking. 46 00:06:54,560 --> 00:06:56,160 Like the macaques, 47 00:06:56,160 --> 00:06:59,480 his forebears were refugees from the advancing Sahara. 48 00:07:05,200 --> 00:07:07,560 The land is scrubby and dry. 49 00:07:13,040 --> 00:07:15,800 But this stallion has claimed it as his own. 50 00:07:18,120 --> 00:07:20,560 He's been waiting months for visitors. 51 00:07:22,080 --> 00:07:23,560 Female visitors. 52 00:07:32,280 --> 00:07:34,160 If they like his territory, 53 00:07:34,160 --> 00:07:35,920 they might stay a while. 54 00:07:40,800 --> 00:07:45,320 It's his first chance to mate for a very long time. 55 00:07:57,280 --> 00:07:58,760 HE BRAYS 56 00:07:58,760 --> 00:08:00,120 Hardly a success. 57 00:08:02,240 --> 00:08:06,000 Perhaps his visitors are looking for a more impressive partner. 58 00:08:09,280 --> 00:08:11,240 There's another setback. 59 00:08:13,040 --> 00:08:15,080 The females were being followed, 60 00:08:15,080 --> 00:08:17,560 a posse of young males, 61 00:08:17,560 --> 00:08:19,480 every one, a rival. 62 00:08:25,520 --> 00:08:28,800 It's time to separate the men from the boys. 63 00:08:38,920 --> 00:08:40,520 HE SNORTS 64 00:08:44,440 --> 00:08:45,720 HE BRAYS 65 00:08:51,000 --> 00:08:52,800 HE BRAYS 66 00:08:54,520 --> 00:08:57,800 One by one, the stallion sees them off. 67 00:09:04,960 --> 00:09:06,720 HE BRAYS 68 00:09:21,560 --> 00:09:24,080 The females had ringside seats. 69 00:09:26,000 --> 00:09:29,640 And his prowess has not gone unnoted. 70 00:09:36,720 --> 00:09:39,680 Machismo gives way to tenderness. 71 00:09:56,880 --> 00:10:00,440 Around here, you have to take every opportunity, 72 00:10:00,440 --> 00:10:03,920 be it for food, for water or for mates. 73 00:10:14,880 --> 00:10:18,120 Female Grevy's are a fickle bunch. 74 00:10:18,120 --> 00:10:20,320 The herd have decided to move on. 75 00:10:22,080 --> 00:10:24,080 All of them. 76 00:10:24,080 --> 00:10:25,440 HE NEIGHS 77 00:10:25,440 --> 00:10:28,480 The stallion may never see them again. 78 00:10:28,480 --> 00:10:32,760 But there's a chance that one is now carrying his foal. 79 00:10:35,040 --> 00:10:39,320 In this harsh land THAT must count as a triumph. 80 00:10:48,240 --> 00:10:52,560 The sun's power cannot, however, reach far underground. 81 00:10:54,560 --> 00:10:56,920 Below, in stark contrast, 82 00:10:56,920 --> 00:10:59,880 conditions are stable and tolerable. 83 00:11:02,240 --> 00:11:05,800 And home to one of the planet's strangest mammals. 84 00:11:10,320 --> 00:11:12,760 Meet the naked mole rats. 85 00:11:18,960 --> 00:11:24,240 These sabre-toothed sausages wouldn't last a day in the desert. 86 00:11:25,760 --> 00:11:28,160 Special filming tunnels allow us to see 87 00:11:28,160 --> 00:11:31,240 how well adapted they are to the subterranean life. 88 00:11:31,240 --> 00:11:34,200 They can run equally well in both directions, 89 00:11:34,200 --> 00:11:36,240 so tight space is no problem. 90 00:11:41,240 --> 00:11:43,040 They have lost their fur. 91 00:11:45,360 --> 00:11:48,680 And, most bizarrely, they live in social colonies, 92 00:11:48,680 --> 00:11:51,800 much like termites or ants. 93 00:11:55,600 --> 00:11:57,320 After time spent digging, 94 00:11:57,320 --> 00:11:59,680 the workers come together to relax. 95 00:12:11,680 --> 00:12:15,520 But one here is very different from all the rest. 96 00:12:17,560 --> 00:12:18,720 Their queen. 97 00:12:20,600 --> 00:12:22,840 Twice as heavy as her subjects, 98 00:12:22,840 --> 00:12:25,840 and not afraid to throw her weight around. 99 00:12:30,000 --> 00:12:33,360 She is the mother of every worker in the colony, 100 00:12:33,360 --> 00:12:37,200 and exists in a near-continuous state of pregnancy. 101 00:12:39,960 --> 00:12:44,680 Even now, two dozen babies are pulsating within her swollen belly. 102 00:12:50,680 --> 00:12:52,240 Just occasionally, 103 00:12:52,240 --> 00:12:54,840 one of her brood is raised differently. 104 00:12:56,040 --> 00:12:59,120 A daughter becomes a princess. 105 00:13:03,200 --> 00:13:08,120 Until now, this youngster's enjoyed a lazy, privileged life. 106 00:13:08,120 --> 00:13:10,000 But not for much longer. 107 00:13:15,120 --> 00:13:17,960 She has a destiny to fulfil. 108 00:13:25,520 --> 00:13:29,960 The surface is a place where no naked mole rat can survive for long. 109 00:13:37,800 --> 00:13:42,280 But a princess will risk everything to search for a partner. 110 00:13:51,240 --> 00:13:53,080 The quest is urgent. 111 00:13:59,520 --> 00:14:00,960 IT SNIFFS 112 00:14:00,960 --> 00:14:03,760 There's an enticing smell in the air. 113 00:14:12,520 --> 00:14:16,680 A seductive scent draws her downwards, to safety. 114 00:14:28,800 --> 00:14:31,040 She's sniffed out a partner. 115 00:14:34,440 --> 00:14:36,320 He too is alone, 116 00:14:36,320 --> 00:14:40,040 and eager to start a new colony in his lonely burrow. 117 00:14:43,400 --> 00:14:45,000 Two months later, 118 00:14:45,000 --> 00:14:47,360 the princess has become a queen. 119 00:14:47,360 --> 00:14:49,720 And a new tyranny begins. 120 00:14:57,600 --> 00:14:59,640 Tough though they are, 121 00:14:59,640 --> 00:15:03,880 such refugees living on the edges of North Africa 122 00:15:03,880 --> 00:15:07,280 cannot survive in the heart of the Sahara. 123 00:15:11,840 --> 00:15:14,600 And yet here, in southern Nigeria, 124 00:15:14,600 --> 00:15:18,240 there are creatures preparing to journey right across the centre 125 00:15:18,240 --> 00:15:19,880 of that great desert. 126 00:15:24,760 --> 00:15:26,640 Barn swallows. 127 00:15:31,840 --> 00:15:34,760 IT SINGS 128 00:15:34,760 --> 00:15:38,240 They spent the winter roosting in a forest of elephant grass. 129 00:15:41,160 --> 00:15:44,000 But now, it's time for them to leave. 130 00:15:49,080 --> 00:15:51,760 All two million of them. 131 00:16:14,680 --> 00:16:20,040 They're tiny, each weighing the same as a couple of one pound coins, 132 00:16:20,040 --> 00:16:23,240 yet the journey to their breeding grounds in Europe 133 00:16:23,240 --> 00:16:25,160 is over 3,000 miles long. 134 00:16:27,960 --> 00:16:31,080 Ahead of them lies a vast death trap. 135 00:16:34,600 --> 00:16:37,640 The Sahara is too large to go around. 136 00:16:37,640 --> 00:16:42,080 The swallows have no choice but to meet it head-on. 137 00:16:53,800 --> 00:16:57,120 It will take one of nature's greatest feats of navigation 138 00:16:57,120 --> 00:16:59,480 to cross this lifeless wasteland. 139 00:17:01,920 --> 00:17:06,040 A wilderness that stretches not just to the horizon, 140 00:17:06,040 --> 00:17:08,760 but almost beyond imagination. 141 00:17:17,760 --> 00:17:21,480 It's an immense blank space on the map. 142 00:17:28,920 --> 00:17:31,800 In spite of the Sahara's reputation, 143 00:17:31,800 --> 00:17:34,040 less than one-fifth of it is sand. 144 00:17:37,240 --> 00:17:40,040 The rest is stone 145 00:17:40,040 --> 00:17:41,840 and wind-scoured rock. 146 00:17:51,600 --> 00:17:55,160 The sun not only bakes the land, 147 00:17:55,160 --> 00:17:57,280 it warps its appearance. 148 00:18:00,520 --> 00:18:04,680 The superheated air, rising upward from the desert surface, 149 00:18:04,680 --> 00:18:06,800 distorts the distant scene. 150 00:18:11,040 --> 00:18:16,000 A reflection of the sky shimmers on the sands - a mirage. 151 00:18:22,360 --> 00:18:24,960 The sun is an illusionist. 152 00:18:28,640 --> 00:18:30,600 To thirsty travellers, 153 00:18:30,600 --> 00:18:32,320 a mirage can resemble a lake 154 00:18:32,320 --> 00:18:36,160 which agonisingly recedes as it's approached. 155 00:18:44,400 --> 00:18:47,640 And swaying camels coming to the rescue 156 00:18:47,640 --> 00:18:51,360 transform into dry, spiny acacia trees. 157 00:19:02,360 --> 00:19:06,240 To cross this confused, shimmering landscape, 158 00:19:06,240 --> 00:19:11,080 many swallows will need to find real water amongst the mirages. 159 00:19:17,960 --> 00:19:22,400 Even in the Sahara, rain does sometimes fall 160 00:19:22,400 --> 00:19:25,760 and that is sufficient for plants to survive 161 00:19:25,760 --> 00:19:28,520 providing they have the right adaptations. 162 00:19:29,760 --> 00:19:31,920 Rising from the sand, 163 00:19:31,920 --> 00:19:34,120 a dried-out ball of twigs. 164 00:19:41,760 --> 00:19:44,160 In strong winds, it can travel. 165 00:20:01,920 --> 00:20:04,720 This plant may have been dead for 100 years. 166 00:20:08,640 --> 00:20:12,640 Yet its name suggests that all is not lost, 167 00:20:12,640 --> 00:20:15,160 for this is a resurrection plant. 168 00:20:23,320 --> 00:20:27,120 Around here, rain might only fall once or twice a year. 169 00:20:31,040 --> 00:20:33,480 But if you're searching for decades, 170 00:20:33,480 --> 00:20:35,240 that might be enough. 171 00:20:42,160 --> 00:20:44,560 Dead limbs absorb water 172 00:20:44,560 --> 00:20:47,320 and unfurl in a matter of minutes. 173 00:20:49,920 --> 00:20:53,600 But the resurrection plant needs one more miracle. 174 00:20:57,120 --> 00:20:59,560 THUNDER 175 00:21:00,760 --> 00:21:03,960 Rain must fall on its branches 176 00:21:03,960 --> 00:21:06,560 before they dry out and close up again. 177 00:22:04,320 --> 00:22:07,560 Within hours, shoots emerge. 178 00:22:23,720 --> 00:22:26,800 In just a few weeks, they flower 179 00:22:26,800 --> 00:22:28,880 and develop seeds of their own. 180 00:22:35,880 --> 00:22:38,880 Then, before they can grow any larger, 181 00:22:38,880 --> 00:22:41,440 the sun kills them. 182 00:22:47,080 --> 00:22:48,800 But their seeds live on, 183 00:22:48,800 --> 00:22:50,880 ready for when the rains return, 184 00:22:50,880 --> 00:22:53,840 even if that is a century from now. 185 00:22:58,280 --> 00:23:01,640 North Africa wasn't always so brutal. 186 00:23:01,640 --> 00:23:04,920 Scattered across the Sahara are glimpses of life 187 00:23:04,920 --> 00:23:08,120 before the apocalypse swept over the land. 188 00:23:11,520 --> 00:23:14,200 In the north, a petrified forest - 189 00:23:14,200 --> 00:23:16,040 trees turned to stone. 190 00:23:16,040 --> 00:23:19,480 Remains from a far distant, wetter past. 191 00:23:24,160 --> 00:23:28,560 White sediments in the heart of the Sahara are the dried-out remains 192 00:23:28,560 --> 00:23:31,880 of what was once the world's largest lake. 193 00:23:35,560 --> 00:23:39,320 In the east, ruined cities hark back to a time of plenty. 194 00:23:47,520 --> 00:23:50,280 And here, deep inside Libya, 195 00:23:50,280 --> 00:23:52,160 is Messak Settafet. 196 00:23:56,800 --> 00:24:02,920 Carved here are hundreds of images of animals, all drawn from life. 197 00:24:07,120 --> 00:24:09,920 Ghosts from a greener time. 198 00:24:15,280 --> 00:24:20,200 Remarkably, a remnant of this old North Africa survives. 199 00:24:24,400 --> 00:24:29,800 Bou-Hedma, in Tunisia, is sustained by mountain rains. 200 00:24:34,560 --> 00:24:36,200 It's a relic of the savannah 201 00:24:36,200 --> 00:24:38,440 that once carpeted North Africa. 202 00:24:51,000 --> 00:24:52,960 The vast grassland vanished 203 00:24:52,960 --> 00:24:57,480 when a shift in the Earth's orbit drove the rains south 204 00:24:57,480 --> 00:25:00,480 and, in perhaps only a matter of centuries, 205 00:25:00,480 --> 00:25:03,400 the Sahara Desert overwhelmed North Africa. 206 00:25:08,160 --> 00:25:12,600 The evidence suggests this took place around 6,000 years ago. 207 00:25:12,600 --> 00:25:15,680 In evolutionary terms, that's no time at all 208 00:25:15,680 --> 00:25:19,880 and life has had little chance to adapt to this new world. 209 00:25:26,520 --> 00:25:31,920 Only a few tough specialists can cope with life amongst the dunes. 210 00:25:40,360 --> 00:25:41,760 THEY GRUNT 211 00:25:47,280 --> 00:25:49,120 THEY GRUNT 212 00:25:50,160 --> 00:25:54,040 Camels are sometimes called "ships of the desert" 213 00:25:54,040 --> 00:25:55,200 but, like the swallows, 214 00:25:55,200 --> 00:25:57,760 they're really only visitors here. 215 00:25:59,160 --> 00:26:02,400 These "ships" can certainly cross the Sahara, 216 00:26:02,400 --> 00:26:06,440 but even THEY can't make their home in the harshest places. 217 00:26:11,560 --> 00:26:14,080 Left to wander the desert by themselves, 218 00:26:14,080 --> 00:26:16,920 camels would not survive. 219 00:26:16,920 --> 00:26:21,640 They depend on their human navigators to find oases and wells. 220 00:26:28,480 --> 00:26:32,200 Saharan folklore is full of tales of caravans 221 00:26:32,200 --> 00:26:36,400 that missed a well by a few hundred metres and disappeared. 222 00:26:51,240 --> 00:26:54,920 This is the White Desert, in Egypt. 223 00:27:00,120 --> 00:27:04,560 The landscape is littered with giant chalk pillars, 224 00:27:04,560 --> 00:27:08,200 carved by innumerable sandstorms. 225 00:27:12,400 --> 00:27:16,200 This glaring white oven is lethally hot. 226 00:27:19,000 --> 00:27:22,240 Food here is almost non-existent. 227 00:27:25,560 --> 00:27:29,000 But there's a rare gift from a passing camel. 228 00:27:29,000 --> 00:27:32,720 The smell has lured dung beetles from miles around. 229 00:27:35,040 --> 00:27:37,920 For them, this is manna from heaven. 230 00:27:45,320 --> 00:27:48,080 One dung ball could provide enough food 231 00:27:48,080 --> 00:27:51,400 to last this female beetle the rest of her life. 232 00:27:53,440 --> 00:27:55,040 But she has a problem. 233 00:27:56,280 --> 00:27:57,520 To keep it fresh, 234 00:27:57,520 --> 00:28:00,120 she must bury it in moist ground. 235 00:28:00,120 --> 00:28:02,480 And that's not easy to find. 236 00:28:10,960 --> 00:28:14,600 The temperature has already risen ten degrees. 237 00:28:20,480 --> 00:28:23,480 This lizard avoids the roasting sand. 238 00:28:24,960 --> 00:28:27,160 Only 30 centimetres above the surface, 239 00:28:27,160 --> 00:28:29,440 it's significantly cooler. 240 00:28:37,440 --> 00:28:40,760 The 'reverse-pushing' technique 241 00:28:40,760 --> 00:28:42,360 is certainly the fastest way 242 00:28:42,360 --> 00:28:43,840 to keep the ball rolling. 243 00:28:49,360 --> 00:28:51,800 But it does have one drawback. 244 00:29:00,760 --> 00:29:02,680 You can't see where you're going. 245 00:29:07,400 --> 00:29:08,800 Disaster! 246 00:29:10,080 --> 00:29:12,760 Stuck between two dunes. 247 00:29:20,960 --> 00:29:23,680 The dung ball is twice her weight, 248 00:29:23,680 --> 00:29:27,800 but the urge to keep pushing is inextinguishable. 249 00:30:11,440 --> 00:30:15,920 Now, it's 41 degrees Celsius. 250 00:30:15,920 --> 00:30:18,680 Soon, she'll be baked alive. 251 00:30:22,680 --> 00:30:28,440 Her survival instinct, in the end, over-rides her love for dung. 252 00:30:39,840 --> 00:30:44,240 Much of the Sahara is uninhabitable, but there are rare places 253 00:30:44,240 --> 00:30:47,240 where there is some possibility of survival. 254 00:30:47,240 --> 00:30:51,560 Places where, by strange chance, there is water. 255 00:30:55,600 --> 00:30:59,080 Waw An Namus is an extinct volcano. 256 00:31:00,080 --> 00:31:05,240 From space, it's a remote, black scar on the Libyan Sahara. 257 00:31:12,240 --> 00:31:15,000 Yet there are other colours here, 258 00:31:15,000 --> 00:31:18,160 colours rarely seen on the desert floor. 259 00:31:19,880 --> 00:31:23,480 Blue and green. 260 00:31:36,000 --> 00:31:40,440 Rain fell thousands of years ago, when the Sahara was green 261 00:31:40,440 --> 00:31:43,240 and percolated deep into the ground. 262 00:31:44,400 --> 00:31:47,000 And here water from this vast, 263 00:31:47,000 --> 00:31:50,200 ancient reservoir rises to the surface. 264 00:31:52,560 --> 00:31:57,320 These pools offer another glimpse of the Sahara's past. 265 00:32:03,920 --> 00:32:06,600 Wherever there's water in North Africa, 266 00:32:06,600 --> 00:32:11,200 living relics from this wetter time have a chance to cling on. 267 00:32:14,400 --> 00:32:19,440 This oasis is fed by a hot volcanic spring. 268 00:32:24,400 --> 00:32:28,120 Slightly away from the stream of near-boiling water, 269 00:32:28,120 --> 00:32:31,080 its cooler, and fish can live. 270 00:32:31,080 --> 00:32:33,680 These are tilapia. 271 00:32:36,280 --> 00:32:39,640 Hatchlings stick close to their mother. 272 00:32:39,640 --> 00:32:43,360 There are other dangers here beside the scalding water. 273 00:32:47,800 --> 00:32:51,040 Particularly at night. 274 00:33:01,120 --> 00:33:04,280 The crocodiles are stealthy. 275 00:33:12,200 --> 00:33:17,320 And the tilapia are almost blind in the darkness. 276 00:33:22,760 --> 00:33:26,600 In panic, they all leap to escape the hunters' approach. 277 00:33:33,480 --> 00:33:37,360 But this female can't abandon her brood. 278 00:33:44,760 --> 00:33:48,800 The crocodiles won't be thwarted. They too can leap. 279 00:34:33,120 --> 00:34:38,040 With first light, the crocodiles lose the element of surprise, 280 00:34:38,040 --> 00:34:40,520 and the battle is over, for now. 281 00:34:42,240 --> 00:34:47,160 The mother fish has survived, but where are her young? 282 00:34:50,880 --> 00:34:54,080 All present and correct. 283 00:34:54,080 --> 00:34:58,320 They spent the whole night sheltering in her mouth. 284 00:34:59,600 --> 00:35:02,560 The contest will be repeated at sunset. 285 00:35:03,600 --> 00:35:05,880 There is nowhere else to go. 286 00:35:11,240 --> 00:35:14,880 Oases are always sought by desert travellers, 287 00:35:14,880 --> 00:35:17,320 but not all are as they seem. 288 00:35:25,160 --> 00:35:31,600 This is the great Ubari Sand Sea, in the heart of the Sahara. 289 00:35:35,280 --> 00:35:39,600 These swallows have travelled 1,500 miles 290 00:35:39,600 --> 00:35:41,520 since they left Nigeria. 291 00:35:43,440 --> 00:35:47,400 Their superb powers of navigation will eventually guide them 292 00:35:47,400 --> 00:35:51,160 to Europe, but now they, and other thirsty migrants, 293 00:35:51,160 --> 00:35:55,960 need to find a speck of blue amidst this ocean of sand. 294 00:36:00,560 --> 00:36:03,160 And here it is. 295 00:36:03,160 --> 00:36:05,400 Umm el Mar. 296 00:36:13,520 --> 00:36:17,720 Here too, ancient groundwater wells up to the surface. 297 00:36:37,680 --> 00:36:40,240 But the birds need to be careful, 298 00:36:40,240 --> 00:36:43,600 for the sun has played a terrible trick. 299 00:36:51,040 --> 00:36:54,440 This oasis is poisonous. 300 00:36:56,920 --> 00:37:01,240 Intense evaporation over thousands of years has left the water 301 00:37:01,240 --> 00:37:03,400 saltier than the sea. 302 00:37:05,960 --> 00:37:08,040 As if to underline the horror, 303 00:37:08,040 --> 00:37:12,000 the place is infested by vast swarms of flies. 304 00:37:16,440 --> 00:37:19,760 But this plague is a birds' salvation. 305 00:37:23,960 --> 00:37:29,080 The flies are filled with freshwater, filtered from the brine. 306 00:37:35,040 --> 00:37:39,120 So, like a desert wanderer squeezing a drink from a cactus, 307 00:37:39,120 --> 00:37:44,000 the birds get all the water they need from the flies' bodies. 308 00:37:51,520 --> 00:37:54,560 More and more migrants join in. 309 00:37:56,720 --> 00:37:59,000 Wagtails. 310 00:38:14,200 --> 00:38:16,680 This is the birds' only stopover. 311 00:38:18,320 --> 00:38:24,480 It gives them enough fuel to escape from the Sahara and Africa. 312 00:38:27,400 --> 00:38:29,240 Away from an oasis, 313 00:38:29,240 --> 00:38:33,000 it seems remarkable that anything can live at all. 314 00:38:37,600 --> 00:38:41,560 The temperature of the sands can exceed 70 degrees Celsius. 315 00:38:43,880 --> 00:38:48,120 There's not the slightest trace of water left at the surface. 316 00:38:53,200 --> 00:38:58,200 And when that happens, the Sahara itself cries out. 317 00:39:02,760 --> 00:39:05,440 LOUD HUMMING 318 00:39:33,960 --> 00:39:37,480 Billions of sliding grains generate a hum 319 00:39:37,480 --> 00:39:40,720 that echoes across miles of empty desert. 320 00:39:42,120 --> 00:39:46,640 These are the Sahara's legendary singing dunes. 321 00:40:12,120 --> 00:40:15,680 Over time, these avalanches add up. 322 00:40:19,840 --> 00:40:22,080 If you watch the dunes for long enough, 323 00:40:22,080 --> 00:40:24,640 something remarkable is revealed. 324 00:40:27,280 --> 00:40:31,480 One and a half years flash past in a matter of seconds. 325 00:40:40,400 --> 00:40:44,640 On this timescale, the dunes are like a stormy sea. 326 00:40:51,200 --> 00:40:55,040 An unstoppable tsunami of sand. 327 00:41:03,160 --> 00:41:06,560 In this immense, ever-shifting landscape, 328 00:41:06,560 --> 00:41:09,800 it's easy to see how a lost traveller could succumb 329 00:41:09,800 --> 00:41:14,760 to what's been called the Sahara's only endemic disease - 330 00:41:14,760 --> 00:41:16,520 madness. 331 00:41:34,600 --> 00:41:38,520 Can anything survive the North African desert 332 00:41:38,520 --> 00:41:41,360 when the sun is at its fiercest? 333 00:41:47,080 --> 00:41:50,440 It's approaching mid-day. 334 00:41:50,440 --> 00:41:53,680 A fringe-toed lizard is hungry. 335 00:41:54,760 --> 00:41:57,080 He's on a stake-out. 336 00:42:05,360 --> 00:42:09,600 Flashy scales reflect some of the sun's rays. 337 00:42:11,240 --> 00:42:15,080 Nevertheless, the heat is almost unbearable. 338 00:42:19,200 --> 00:42:22,400 His prey hasn't left home all day. 339 00:42:34,760 --> 00:42:39,480 The lizard is the last animal still out on the dunes. 340 00:42:43,480 --> 00:42:46,600 But even he can't take it any more. 341 00:42:48,040 --> 00:42:51,680 To survive longer, you would need a spacesuit. 342 00:42:55,120 --> 00:42:59,040 And in a way, that's what these insects have. 343 00:43:02,200 --> 00:43:06,280 Silver ants' armoured skin reflects light. 344 00:43:06,280 --> 00:43:11,040 They can tolerate temperatures that would kill any other land animal. 345 00:43:12,720 --> 00:43:16,800 Even so, they can only survive for less than ten minutes 346 00:43:16,800 --> 00:43:18,480 in the midday sun. 347 00:43:27,600 --> 00:43:30,160 Time is precious. 348 00:43:30,160 --> 00:43:34,880 The ants race to find food as soon as their predators go to ground. 349 00:43:43,920 --> 00:43:47,040 They can't afford to waste a second getting lost, 350 00:43:47,040 --> 00:43:50,320 so they spin to take a bearing from the sun. 351 00:43:51,440 --> 00:43:55,120 They log every change of direction, every footstep, 352 00:43:55,120 --> 00:43:58,880 in order to know exactly where they are and where their nest lies. 353 00:44:05,040 --> 00:44:06,960 Only four minutes to spare, 354 00:44:06,960 --> 00:44:11,520 and they've found a victim of heatstroke. A meal. 355 00:44:15,080 --> 00:44:18,800 But it's going to take a monumental effort to get it home. 356 00:44:33,040 --> 00:44:36,920 Three minutes to go and they're nearing their maximum temperature, 357 00:44:36,920 --> 00:44:39,720 an astounding 53 degrees Celsius. 358 00:44:48,640 --> 00:44:51,400 But there are already casualties. 359 00:45:01,840 --> 00:45:04,920 One minute left, and they're not going to make it. 360 00:45:04,920 --> 00:45:06,920 Something has to change. 361 00:45:53,920 --> 00:45:59,040 The silver ant is the hardiest of all desert inhabitants. 362 00:45:59,040 --> 00:46:03,240 Even so, it can only survive outside in the middle of the day 363 00:46:03,240 --> 00:46:04,640 for a matter of minutes. 364 00:46:09,880 --> 00:46:14,520 Now, the desert belongs to the sun alone. 365 00:46:17,360 --> 00:46:21,720 The sun has scorched life from the Sahara. 366 00:46:21,720 --> 00:46:26,200 And yet the vast desert it created is a source of life 367 00:46:26,200 --> 00:46:28,280 half a world away. 368 00:46:32,360 --> 00:46:38,040 The advancing Sahara vaporised the world's largest lake, 369 00:46:38,040 --> 00:46:43,880 leaving behind the silvery remains of countless microscopic algae. 370 00:46:46,600 --> 00:46:51,600 In winter, the wind carries away 700,000 tonnes 371 00:46:51,600 --> 00:46:54,760 of this mineral-rich dust every day. 372 00:46:57,320 --> 00:47:01,200 It blows from here all the way to South America, 373 00:47:01,200 --> 00:47:06,400 where, astonishingly, it fertilises the Amazon rainforest. 374 00:47:12,160 --> 00:47:18,120 A striking demonstration of the reach of this mighty continent. 375 00:47:28,040 --> 00:47:33,840 Throughout its long history, Africa has influenced the entire planet. 376 00:47:33,840 --> 00:47:37,920 It was the cradle of a remarkable array of land animals that spread 377 00:47:37,920 --> 00:47:42,960 across the globe, and, of course, it was the ancestral home of all of us. 378 00:48:13,560 --> 00:48:17,280 This is the tale of two of the Africa team's 379 00:48:17,280 --> 00:48:19,920 most challenging desert expeditions. 380 00:48:24,480 --> 00:48:29,240 One focused on a miniscule creature with an incredible turn of speed. 381 00:48:32,160 --> 00:48:36,520 The other, on a subject so slow, to film it in action would take years. 382 00:48:38,480 --> 00:48:41,360 In both cases, the Sahara would push crews 383 00:48:41,360 --> 00:48:44,400 to the limit in pursuit of the perfect shot. 384 00:48:49,000 --> 00:48:52,840 In Tunisia, the mission is to capture footage of moving 385 00:48:52,840 --> 00:48:57,360 sand dunes, something that's never been tried like this before. 386 00:48:57,360 --> 00:49:01,240 Because the dunes move so slowly, we'll have to leave cameras here 387 00:49:01,240 --> 00:49:02,280 for about 20 months, 388 00:49:02,280 --> 00:49:04,960 which means there's a huge potential for things to go wrong. 389 00:49:06,200 --> 00:49:10,520 And with film-making, if something can go wrong, it usually will. 390 00:49:12,000 --> 00:49:15,040 Two local shepherds, Amur and Nasser, 391 00:49:15,040 --> 00:49:18,000 have volunteered to tend the equipment full-time. 392 00:49:20,720 --> 00:49:23,920 The camera tower will be the tallest structure 393 00:49:23,920 --> 00:49:26,040 for as far as the eye can see. 394 00:49:29,640 --> 00:49:33,160 And there are three other cameras at lower angles. 395 00:49:34,960 --> 00:49:39,960 All this toil will yield surprisingly scant results. 396 00:49:39,960 --> 00:49:44,080 They've programmed the cameras to take one photo every day. 397 00:49:44,080 --> 00:49:47,880 That's only 365 photographs a year... 398 00:49:47,880 --> 00:49:51,400 which, when you run it at normal speed, just over 14 seconds. 399 00:49:51,400 --> 00:49:56,360 I think it's taken longer to explain what's going to happen 400 00:49:56,360 --> 00:49:58,920 than the end result will actually be. 401 00:49:58,920 --> 00:50:02,800 The cameras are left to the mercy of the sun, wind and sand. 402 00:50:04,680 --> 00:50:09,040 In the meantime, crews are shooting all across North Africa. 403 00:50:11,880 --> 00:50:15,720 In Egypt, the challenge is to get into the world of the most 404 00:50:15,720 --> 00:50:19,480 heat-tolerant desert animal, the silver ant. 405 00:50:19,480 --> 00:50:22,400 They're really small, they're really fast. 406 00:50:22,400 --> 00:50:25,080 Like, you're not too sure if you've seen an ant. 407 00:50:26,920 --> 00:50:30,960 The crew have three weeks to gather the footage they need. 408 00:50:32,280 --> 00:50:35,120 We're going to try a tracking shot on this ant nest. 409 00:50:35,120 --> 00:50:38,440 Moving forward towards it, 410 00:50:38,440 --> 00:50:41,840 as the ants pour out of the hole in their millions. 411 00:50:41,840 --> 00:50:44,840 Not only are these insects super-fast, 412 00:50:44,840 --> 00:50:47,440 they also keep antisocial hours. 413 00:50:47,440 --> 00:50:48,840 The thing is, 414 00:50:48,840 --> 00:50:52,480 we need to be out here in the middle of the day to film these ants. 415 00:50:52,480 --> 00:50:55,840 They don't do what they do when it's nice and cool at seven, 416 00:50:55,840 --> 00:50:58,000 eight o'clock in the morning. 417 00:50:58,000 --> 00:51:01,160 I can't remember ever being in a place where the wind was 418 00:51:01,160 --> 00:51:03,960 so relentless and the temperatures were so high. 419 00:51:07,000 --> 00:51:10,640 The insufferable heat is not the only problem. 420 00:51:10,640 --> 00:51:12,680 Dangers are everywhere. 421 00:51:12,680 --> 00:51:15,120 Ooh! 422 00:51:15,120 --> 00:51:18,520 There's a really fat scorpion, it's really big! 423 00:51:18,520 --> 00:51:20,040 One, two, three. 424 00:51:24,040 --> 00:51:25,280 This might kill. 425 00:51:25,280 --> 00:51:27,360 - Yeah? - Yeah. 426 00:51:27,360 --> 00:51:31,720 It's big and they have a lot of poison in his dark thing. 427 00:51:31,720 --> 00:51:33,880 What, that thing there? 428 00:51:33,880 --> 00:51:35,280 Don't! Oh, my god! 429 00:51:35,280 --> 00:51:36,720 Don't touch it! 430 00:51:36,720 --> 00:51:40,600 The scorpion will be released far, far away from the camp, 431 00:51:40,600 --> 00:51:43,320 in a shady spot. 432 00:51:43,320 --> 00:51:45,360 No such luck for the team. 433 00:51:45,360 --> 00:51:49,000 They're back to work in the midday sun. 434 00:51:49,000 --> 00:51:53,440 This is, this is too much. This is crazy. 435 00:51:53,440 --> 00:51:54,880 This is crazy. 436 00:51:54,880 --> 00:51:55,960 Indeed. 437 00:51:55,960 --> 00:52:00,000 The heat seems to have given Kat and Warwick a touch of Saharan madness. 438 00:52:01,680 --> 00:52:03,960 The plan is to do an experiment, 439 00:52:03,960 --> 00:52:08,600 to find out how fast these little ants can run. 440 00:52:08,600 --> 00:52:13,480 So we're going to lay this along the floor, and hopefully an ant will 441 00:52:13,480 --> 00:52:16,760 run alongside it and we can film it at high speed. 442 00:52:16,760 --> 00:52:20,080 And from that, calculate their... their speed, 443 00:52:20,080 --> 00:52:24,400 and perhaps try and relate it to how fast that would be for a human. 444 00:52:24,400 --> 00:52:26,640 Like me. 445 00:52:26,640 --> 00:52:29,080 Silver ants are expert navigators, 446 00:52:29,080 --> 00:52:32,600 using the angle of the sun to calculate their position. 447 00:52:32,600 --> 00:52:37,720 But for our team, even basic mental tasks are becoming a challenge. 448 00:52:37,720 --> 00:52:41,120 Count the seconds. See one running and then count the seconds. 449 00:52:41,120 --> 00:52:44,480 - It's difficult to count a second, isn't it? - No, it's "one". 450 00:52:46,360 --> 00:52:48,680 "One", yeah! 451 00:52:53,160 --> 00:52:54,680 There he goes! 452 00:52:56,760 --> 00:52:59,400 He's gone ten centimetres in four seconds, 453 00:52:59,400 --> 00:53:02,800 but we're running at 500 frames a second, 454 00:53:02,800 --> 00:53:04,600 which is 20 times normal time. 455 00:53:04,600 --> 00:53:08,880 - Yeah. - So in fact, he's covered those ten centimetres in... 456 00:53:12,760 --> 00:53:16,000 We know that he does half a metre in one second. 457 00:53:16,000 --> 00:53:18,440 Half a metre per second, yep. 458 00:53:18,440 --> 00:53:22,240 - 50 centimetres in one second, roughly. - Yeah. 459 00:53:22,240 --> 00:53:25,040 So, how many body lengths is that? 460 00:53:26,920 --> 00:53:29,440 He's maybe doing five body lengths a second, 461 00:53:29,440 --> 00:53:31,040 if he's two metres tall like I am. 462 00:53:31,040 --> 00:53:34,400 - Are you? - Yeah. That's how much more than a normal man I am. 463 00:53:40,200 --> 00:53:45,320 Eventually, the duo decide that if the silver ants were our size, 464 00:53:45,320 --> 00:53:49,160 they'd be doing 280 miles an hour. 465 00:53:52,000 --> 00:53:55,600 They're one of the fastest sprinters in the animal kingdom. 466 00:53:55,600 --> 00:53:58,280 No wonder we've been struggling to film them. 467 00:53:58,280 --> 00:53:59,920 It does explain a few things. 468 00:54:01,800 --> 00:54:03,960 Ant-letics! 469 00:54:07,480 --> 00:54:11,120 Knowing the exact speed of the ants is all well and good, but there's 470 00:54:11,120 --> 00:54:14,680 still a great deal of work to be done before the shoot finishes. 471 00:54:16,440 --> 00:54:21,320 However, in Tunisia, there's no shortage of time, and hopefully, 472 00:54:21,320 --> 00:54:25,680 no news is good news, as far as Amur and Nasser are concerned. 473 00:54:30,240 --> 00:54:32,800 The final week in Egypt, 474 00:54:32,800 --> 00:54:36,200 and the crew seem to be adapting to life in the oven. 475 00:54:39,520 --> 00:54:43,680 Practice is making perfect, and the sequence is coming together. 476 00:54:46,880 --> 00:54:49,120 I think we've got some lovely shots. 477 00:54:49,120 --> 00:54:51,600 Every single shot has been really hard-earned. 478 00:54:51,600 --> 00:54:55,880 But getting down in the ant's world is now taking its toll on the kit. 479 00:54:55,880 --> 00:54:57,560 It's running to stand still, 480 00:54:57,560 --> 00:55:00,240 the business of blowing dust off these things. 481 00:55:01,840 --> 00:55:03,480 Oh, no! 482 00:55:03,480 --> 00:55:05,320 It's got dust in it! 483 00:55:05,320 --> 00:55:06,520 CRUNCH 484 00:55:06,520 --> 00:55:08,080 Ooh, crunch. 485 00:55:10,640 --> 00:55:12,760 I think these ants are stunning looking. 486 00:55:12,760 --> 00:55:15,720 Near-impossible to film, I think, because of the speed they had. 487 00:55:15,720 --> 00:55:19,520 But, you know, I've come to love them over the days and weeks. 488 00:55:21,480 --> 00:55:23,200 With the sequence in the bag, 489 00:55:23,200 --> 00:55:26,800 Warwick wants the final traditional sunset shot. 490 00:55:27,800 --> 00:55:31,200 It's the best time of day to film sunsets, in the evening. 491 00:55:32,800 --> 00:55:34,880 That's experience that tells me that. 492 00:55:34,880 --> 00:55:37,720 I've been doing this for years. You learn these things. 493 00:55:37,720 --> 00:55:42,280 Thanks to Warwick's experience, including sunsets, he and Kat 494 00:55:42,280 --> 00:55:47,280 have captured the extraordinary life of the speedy silver ant. 495 00:55:50,280 --> 00:55:52,840 Over a year later, in Tunisia, 496 00:55:52,840 --> 00:55:56,440 it's time to take down the sand dune cameras. 497 00:55:57,480 --> 00:55:59,600 Bonjour! 498 00:55:59,600 --> 00:56:03,880 Nasser, Amur. Hello again. 499 00:56:03,880 --> 00:56:05,720 So how's it been, has it been good? 500 00:56:05,720 --> 00:56:10,960 It's OK, but two days ago, we have a little bit...small problem. 501 00:56:10,960 --> 00:56:13,760 After surviving 600 days in the desert, 502 00:56:13,760 --> 00:56:17,880 the "small problem" is that the cameras have been vandalised. 503 00:56:20,720 --> 00:56:23,360 I'm really hot and bothered now, it's 40 degrees, 504 00:56:23,360 --> 00:56:27,280 and someone's smashed the cameras. 505 00:56:27,280 --> 00:56:30,000 Not been a good start to the day, to be honest. 506 00:56:31,040 --> 00:56:33,560 There's no doubt the dunes have moved. 507 00:56:33,560 --> 00:56:37,240 But the question is whether the equipment has survived. 508 00:56:40,400 --> 00:56:42,600 That is amazing, the camera's still here. 509 00:56:42,600 --> 00:56:46,200 I guess maybe it just took them so long to get through the toughened plastic, 510 00:56:46,200 --> 00:56:49,920 that they felt they had made so much noise they were worried about the guards coming, 511 00:56:49,920 --> 00:56:52,640 because they only sleep a couple of 100 metres away. 512 00:56:52,640 --> 00:56:57,680 After almost two years of waiting, it's the moment of truth. 513 00:57:00,000 --> 00:57:03,320 We're going to find out, find out whether or not 514 00:57:03,320 --> 00:57:06,200 the cameras have actually recorded anything. 515 00:57:06,200 --> 00:57:09,920 It's just hugely stressful because it's never been done before. 516 00:57:12,360 --> 00:57:16,000 The footage is a surreal window into a secret world - 517 00:57:16,000 --> 00:57:18,760 the private life of a sand dune. 518 00:57:28,560 --> 00:57:31,480 The Africa team struggled under the burning sun 519 00:57:31,480 --> 00:57:35,280 and driving winds that are hallmarks of the Sahara. 520 00:57:40,960 --> 00:57:45,120 They went home with an enormous admiration for the creatures that 521 00:57:45,120 --> 00:57:50,520 spend their entire lives battling to survive in this brutal desert world. 522 00:57:58,440 --> 00:58:02,040 Next time, we'll be looking towards the future of Africa 523 00:58:02,040 --> 00:58:03,840 and its wildlife. 524 00:58:03,840 --> 00:58:09,880 Meeting the remarkable Elvis and his highly endangered family. 525 00:58:09,880 --> 00:58:13,080 Diving with Shella, who's learning to swim again. 526 00:58:14,360 --> 00:58:17,840 Africa's wildlife is at a critical point 527 00:58:17,840 --> 00:58:20,200 as it faces its greatest threat. 528 00:58:21,480 --> 00:58:23,280 As this battle between man 529 00:58:23,280 --> 00:58:27,360 and wildlife happens, in most cases, wildlife is on the losing end. 530 00:58:31,320 --> 00:58:35,040 But there is hope as the new generation takes on the task 531 00:58:35,040 --> 00:58:39,960 of protecting Africa's animals for the 21st century and beyond. 532 00:58:39,960 --> 00:58:44,080 Join me next time for the future of Africa. 533 00:59:01,120 --> 00:59:03,400 Subtitles by Red Bee Media Ltd