1 00:00:05,698 --> 00:00:08,491 [calm music] 2 00:00:09,974 --> 00:00:14,836 [narrator] In every corner of the world today are humans. 3 00:00:14,974 --> 00:00:17,456 Seven billion of us. 4 00:00:17,594 --> 00:00:21,353 How did we come to so dominant our planet? 5 00:00:21,491 --> 00:00:25,111 It's one of science's greatest mysteries. 6 00:00:25,249 --> 00:00:29,905 Amazing new evidence suggests it began in Africa 7 00:00:30,043 --> 00:00:33,249 when a tiny group of people left the continent 8 00:00:33,387 --> 00:00:35,215 on an incredible journey. 9 00:00:35,353 --> 00:00:38,249 [lively music] 10 00:00:38,387 --> 00:00:41,870 Using bones, stones, and genes, 11 00:00:42,008 --> 00:00:45,111 we'll uncover the trails their descendants left 12 00:00:45,249 --> 00:00:46,801 across the world 13 00:00:46,939 --> 00:00:50,560 and find out how their journeys transformed our species 14 00:00:50,698 --> 00:00:53,422 into the people we are today. 15 00:00:53,560 --> 00:00:58,525 We begin by going in search of the first humans. 16 00:00:58,663 --> 00:01:00,767 We discover how we survived 17 00:01:00,905 --> 00:01:04,870 in our dangerous homeland of prehistoric Africa, 18 00:01:05,008 --> 00:01:08,456 and search for the route we took out of Africa 19 00:01:08,594 --> 00:01:12,077 on the way to colonizing the whole world. 20 00:01:15,732 --> 00:01:17,836 [ominous music] 21 00:01:21,456 --> 00:01:23,836 [African tribal music] 22 00:01:25,801 --> 00:01:28,663 [narrator] Where do we all come from? 23 00:01:28,801 --> 00:01:31,801 Where does our human journey begin? 24 00:01:33,629 --> 00:01:35,387 It seems that it's here 25 00:01:35,525 --> 00:01:38,318 in the Great Rift Valley of East Africa 26 00:01:38,456 --> 00:01:41,043 that our species has its homeland. 27 00:01:42,663 --> 00:01:45,456 [children singing in native language] 28 00:01:46,767 --> 00:01:49,629 In all likelihood, we have been living here 29 00:01:49,767 --> 00:01:52,594 for longer than anywhere else on earth. 30 00:01:52,732 --> 00:01:55,043 [singing in native language] 31 00:02:03,387 --> 00:02:07,836 The best evidence for this was discovered in 1967. 32 00:02:08,560 --> 00:02:09,767 Richard Leakey, 33 00:02:09,905 --> 00:02:13,422 son of legendary fossil hunters Mary and Lewis 34 00:02:13,560 --> 00:02:15,594 was following in his parents' footsteps 35 00:02:15,732 --> 00:02:19,491 searching for humankind's origins. 36 00:02:19,629 --> 00:02:22,698 In the first place, I think the perspective that we have 37 00:02:22,836 --> 00:02:25,905 from our prehistoric past is relevant, 38 00:02:26,043 --> 00:02:27,663 but perhaps more importantly, 39 00:02:27,801 --> 00:02:30,456 it's also possible to look into our past 40 00:02:30,594 --> 00:02:33,318 and see why it was that we succeeded 41 00:02:33,456 --> 00:02:35,146 whether other animals failed. 42 00:02:35,284 --> 00:02:36,422 [zooming] 43 00:02:36,560 --> 00:02:38,560 [narrator]Working with a team of scientists, 44 00:02:38,698 --> 00:02:42,111 Leakey set off to explore a remote area 45 00:02:42,249 --> 00:02:46,629 on the far side of the Omo River in southern Ethiopia. 46 00:02:49,387 --> 00:02:53,732 But just reaching the location was an enormous challenge. 47 00:02:55,767 --> 00:02:58,560 And after months of planning they made it 48 00:02:58,698 --> 00:03:01,180 to the banks of the great river, 49 00:03:01,318 --> 00:03:04,180 only to be faced with disaster. 50 00:03:04,318 --> 00:03:06,387 [ominous music] 51 00:03:07,594 --> 00:03:11,663 A huge crocodile attacked their boat, 52 00:03:11,801 --> 00:03:14,905 the crew were lucky to escape with their lives. 53 00:03:15,043 --> 00:03:17,043 [tense music] 54 00:03:20,698 --> 00:03:23,663 And even once they'd managed to make the crossing 55 00:03:23,801 --> 00:03:25,974 their luck didn't improve. 56 00:03:26,111 --> 00:03:28,698 The site was looking fruitless. 57 00:03:31,318 --> 00:03:35,111 Until one of the group spotted some fragments of bone 58 00:03:35,249 --> 00:03:36,836 sticking out of the sand. 59 00:03:38,353 --> 00:03:41,284 When the pieces were painstakingly put together 60 00:03:41,422 --> 00:03:46,008 they revealed this... a human skull. 61 00:03:46,146 --> 00:03:51,525 And in 2005 new dating techniques revealed its age, 62 00:03:51,663 --> 00:03:56,939 around 195,000 years old. 63 00:03:57,077 --> 00:04:01,146 This is the oldest member of our species, 64 00:04:01,284 --> 00:04:04,284 Homo sapiens, ever found. 65 00:04:04,422 --> 00:04:07,249 [uplifting music] 66 00:04:07,387 --> 00:04:11,836 [chanting in native language] 67 00:04:11,974 --> 00:04:16,594 [chanting in native language] 68 00:04:16,732 --> 00:04:20,318 It's good evidence that this region of East Africa 69 00:04:20,456 --> 00:04:23,008 was our first homeland. 70 00:04:23,146 --> 00:04:28,974 [chanting in native language] 71 00:04:29,111 --> 00:04:31,111 But who are we? 72 00:04:31,249 --> 00:04:33,525 And how did we get here? 73 00:04:37,801 --> 00:04:39,870 [gibbering] 74 00:04:40,008 --> 00:04:43,870 The very first human creatures evolved much earlier 75 00:04:44,008 --> 00:04:46,180 than the people of the Omo valley, 76 00:04:46,318 --> 00:04:49,249 around four million years ago. 77 00:04:49,387 --> 00:04:53,284 They were much more ape-like than us. 78 00:04:53,422 --> 00:04:57,387 A series of different species of human then evolved. 79 00:04:57,525 --> 00:05:00,456 They had gradually increased brain size 80 00:05:00,594 --> 00:05:04,663 and were better adapted to life in the African Savannah. 81 00:05:04,801 --> 00:05:08,008 We are the most recent in the line, 82 00:05:08,146 --> 00:05:12,077 Homo sapiens, or modern humans. 83 00:05:12,215 --> 00:05:15,249 [calm music] 84 00:05:15,387 --> 00:05:18,008 The evidence is very fragmented, 85 00:05:18,146 --> 00:05:20,974 but it seems likely our most recent ancestor 86 00:05:21,111 --> 00:05:24,732 is an ancient human creature like this. 87 00:05:24,870 --> 00:05:26,422 [crackling] 88 00:05:30,836 --> 00:05:36,215 In 1921, archaeologists found this skull in a mine pit 89 00:05:36,353 --> 00:05:38,870 in Kawbe in Zambia. 90 00:05:39,008 --> 00:05:42,732 It's a prime example of Homo heidelbergensis. 91 00:05:43,974 --> 00:05:47,870 So what's the difference between him and us? 92 00:05:50,318 --> 00:05:52,732 By comparing him to Herto man, 93 00:05:52,870 --> 00:05:55,560 a well-preserved Homo sapiens skull, 94 00:05:55,698 --> 00:05:58,629 we can see what changed through time. 95 00:05:59,663 --> 00:06:00,801 This is... 96 00:06:01,836 --> 00:06:04,663 a fossil form of modern Homo sapien, 97 00:06:04,801 --> 00:06:08,698 a Herto skull and this one is Kabwe. 98 00:06:10,249 --> 00:06:13,422 What you see, when you see these two 99 00:06:13,560 --> 00:06:16,594 you can see it clearly, they're really different. 100 00:06:17,525 --> 00:06:19,043 [Berhane] As you can see, 101 00:06:19,180 --> 00:06:22,870 Kabwe has lots of primitive features. 102 00:06:23,008 --> 00:06:26,318 The way it's compared to a modern Homo sapien. 103 00:06:28,215 --> 00:06:30,422 Kabwe doesn't have a forehead, 104 00:06:30,560 --> 00:06:33,491 which is typical of primitive forms. 105 00:06:33,629 --> 00:06:36,215 [Berhane] Modern Homo sapiens, that is us, 106 00:06:36,353 --> 00:06:38,422 has a forehead, 107 00:06:38,560 --> 00:06:40,905 and when you see the face, 108 00:06:42,215 --> 00:06:45,698 Kabwe's face jets out more. 109 00:06:48,698 --> 00:06:51,353 [Berhane] It has heavy browage 110 00:06:51,491 --> 00:06:54,077 which you don't see in the modern Homo sapien. 111 00:06:57,732 --> 00:06:59,456 [narrator] When reconstructed 112 00:06:59,594 --> 00:07:02,732 homo heidelbergensis looks similar to us, 113 00:07:02,870 --> 00:07:06,387 apart from his long low head and heavy brow. 114 00:07:09,870 --> 00:07:13,215 But these ancient humans completely died out, 115 00:07:13,353 --> 00:07:17,560 while our species flourished and spread across the planet. 116 00:07:19,077 --> 00:07:22,043 So what was so special about us? 117 00:07:25,698 --> 00:07:28,077 [light music] 118 00:07:28,215 --> 00:07:30,870 When we think about what makes us stand out 119 00:07:31,008 --> 00:07:32,629 from other animals today 120 00:07:32,767 --> 00:07:37,836 we might say art, music, language, religion, 121 00:07:37,974 --> 00:07:41,836 the ability to plan, or to love perhaps. 122 00:07:43,629 --> 00:07:46,387 But has this always been the case? 123 00:07:46,525 --> 00:07:51,077 Did the very first humans share these characteristics with us? 124 00:07:56,422 --> 00:07:58,698 Not all scientists think so. 125 00:08:08,491 --> 00:08:11,905 But recently an astonishing discovery was made 126 00:08:12,043 --> 00:08:16,043 that gives us a clue what our ancestors were really like. 127 00:08:18,870 --> 00:08:20,870 [light music] 128 00:08:23,560 --> 00:08:26,767 The site of the find is 5,000 kilometers 129 00:08:26,905 --> 00:08:31,456 from where the Omo skull was discovered in South Africa. 130 00:08:32,353 --> 00:08:34,491 [waves splashing] 131 00:08:38,215 --> 00:08:41,077 [crashing] 132 00:08:41,215 --> 00:08:45,422 Today, Pinnacle Point is a playground for the rich, 133 00:08:45,560 --> 00:08:48,663 but what lies below the manicured golf course 134 00:08:48,801 --> 00:08:51,215 has seriously changed our understanding 135 00:08:51,353 --> 00:08:54,353 of the behavior of our early ancestors. 136 00:08:57,456 --> 00:09:04,180 [chanting in native language] 137 00:09:04,318 --> 00:09:07,146 And it's all down to this cave. 138 00:09:07,284 --> 00:09:12,318 [chanting in native language] 139 00:09:12,456 --> 00:09:17,974 Because people were here 165,000 years ago, 140 00:09:18,111 --> 00:09:20,974 people apparently just like us. 141 00:09:24,629 --> 00:09:28,491 It's one of the earliest places we're known to have lived. 142 00:09:30,801 --> 00:09:34,180 Well, this cave I know from my experience excavating here 143 00:09:34,318 --> 00:09:36,491 the setting is obviously beautiful, 144 00:09:36,629 --> 00:09:38,387 you can't have a better place to work, 145 00:09:38,525 --> 00:09:41,146 um, but climate-wise it's very comfortable, 146 00:09:41,284 --> 00:09:46,456 it can be stormy and wet outside and in here you're warm and dry. 147 00:09:46,594 --> 00:09:49,008 Um, it's generally protected from the wind. 148 00:09:49,146 --> 00:09:51,422 It's a, it's a good place to live. 149 00:09:51,560 --> 00:09:55,249 [waves splashing] 150 00:09:55,387 --> 00:09:57,974 [narrator]But it's what these people left behind 151 00:09:58,111 --> 00:09:59,525 that suggests they already had 152 00:09:59,663 --> 00:10:03,525 what we regard as typically human qualities. 153 00:10:07,732 --> 00:10:09,905 These types of tools are, are very typical 154 00:10:10,043 --> 00:10:11,422 of what we find in this cave, 155 00:10:11,560 --> 00:10:16,146 um, this is a quart side blade, and this is a quart side point 156 00:10:16,284 --> 00:10:19,318 and alongside these in the oldest deposits, 157 00:10:19,456 --> 00:10:22,525 um, we also find these much smaller bladelets. 158 00:10:24,767 --> 00:10:27,077 They're obviously very small blades 159 00:10:27,215 --> 00:10:28,801 and because of their small size, 160 00:10:28,939 --> 00:10:31,146 it's unlikely that these would have been, 161 00:10:31,284 --> 00:10:33,870 uh, handheld tools for, for cutting. 162 00:10:34,008 --> 00:10:36,422 Um, it's very likely that these represent 163 00:10:36,560 --> 00:10:38,491 some of the earlier stone tools, 164 00:10:38,629 --> 00:10:42,077 uh, that were set into a handle. 165 00:10:42,215 --> 00:10:45,939 [narrator] Tools this complex are typical of our species. 166 00:10:46,077 --> 00:10:50,905 They can be used for cutting wood or plants, butchering meat 167 00:10:51,043 --> 00:10:52,456 and hunting. 168 00:10:54,905 --> 00:10:58,767 [Kyle] These barbs that prevent the tip from pulling out, 169 00:10:58,905 --> 00:11:02,284 the wounds that weapons like these can inflict 170 00:11:02,422 --> 00:11:04,698 creates a, a blood trail that can be tracked. 171 00:11:04,836 --> 00:11:07,905 I think that would be, uh, a pretty effective tool. 172 00:11:09,422 --> 00:11:10,974 [narrator] And from what the archaeologists 173 00:11:11,111 --> 00:11:12,870 are finding in this cave 174 00:11:13,008 --> 00:11:17,456 it seems our ancestors put their tools to good use. 175 00:11:17,594 --> 00:11:21,732 We really find a whole range of food remains, um, 176 00:11:21,870 --> 00:11:23,870 we're talking about land animals, 177 00:11:24,008 --> 00:11:27,249 we're talking about anything from buffalo 178 00:11:27,387 --> 00:11:31,767 to, uh, dune mole rat, to tortoise, 179 00:11:31,905 --> 00:11:35,974 um, so people were at this time very accomplished hunters. 180 00:11:39,249 --> 00:11:40,732 [narrator] But despite their skill 181 00:11:40,870 --> 00:11:43,525 this wasn't an idyllic lifestyle. 182 00:11:43,663 --> 00:11:46,491 Our ancestors weren't the only hunters 183 00:11:46,629 --> 00:11:48,353 living in these caves. 184 00:11:49,249 --> 00:11:51,698 [calm music] 185 00:11:55,939 --> 00:11:57,629 [Kyle] It would not have been a simple trip 186 00:11:57,767 --> 00:11:59,629 to the grocery store to get their food. 187 00:11:59,767 --> 00:12:01,974 -[hyena screams] -[lion grunts] 188 00:12:07,318 --> 00:12:09,698 Very near to this site there's a carnivore den 189 00:12:09,836 --> 00:12:11,077 that we've excavated, 190 00:12:11,215 --> 00:12:14,146 um, it has some extremely large lion teeth in it 191 00:12:14,284 --> 00:12:16,456 so by consequence the, the hyenas that gathered 192 00:12:16,594 --> 00:12:18,905 that lion must have been a pretty large size too. 193 00:12:19,043 --> 00:12:22,974 -[hyena screams] -[lion growls] 194 00:12:25,732 --> 00:12:29,043 [narrator] So with dangerous predators as neighbors, 195 00:12:29,180 --> 00:12:31,836 how did we survive? 196 00:12:31,974 --> 00:12:35,870 A clue is in the floor of the cave at Pinnacle Point. 197 00:12:36,008 --> 00:12:39,905 It's littered with ancient mussel shells. 198 00:12:40,043 --> 00:12:44,077 This is the earliest evidence of humans eating sea food, 199 00:12:44,215 --> 00:12:48,629 and may have given our species a huge advantage, 200 00:12:48,767 --> 00:12:51,146 because by gathering food from the sea 201 00:12:51,284 --> 00:12:52,939 our ancestors didn't have to rely 202 00:12:53,077 --> 00:12:56,836 on outcompeting the lions and hyenas. 203 00:12:56,974 --> 00:12:59,939 And this also reveals something else about us, 204 00:13:00,077 --> 00:13:03,111 something that would really set us apart. 205 00:13:05,663 --> 00:13:07,629 [Kyle] Most of the shellfish that they're collecting 206 00:13:07,767 --> 00:13:10,077 you really have to be able to pay attention to tides 207 00:13:10,215 --> 00:13:13,663 and you have to, to plan your, your visits down to the ocean. 208 00:13:13,801 --> 00:13:16,663 It's, it's not usually the case where you can just walk down 209 00:13:16,801 --> 00:13:18,215 and collect something off the rocks, 210 00:13:18,353 --> 00:13:20,456 you have to pay very careful attention 211 00:13:20,594 --> 00:13:22,870 to both the spring and neap tides 212 00:13:23,008 --> 00:13:24,767 in order not to be swept away. 213 00:13:26,525 --> 00:13:28,629 [narrator] This ability to plan ahead 214 00:13:28,767 --> 00:13:31,905 gave our species an enormous head start. 215 00:13:34,905 --> 00:13:37,836 But there's another discovery at Pinnacle Point 216 00:13:37,974 --> 00:13:39,939 that makes the people who lived here 217 00:13:40,077 --> 00:13:42,594 seem even more like us. 218 00:13:42,732 --> 00:13:47,629 Ochre, a natural pigment often used for creating art. 219 00:13:48,939 --> 00:13:53,629 This piece has been deliberately marked or engraved. 220 00:13:55,318 --> 00:13:58,387 It may have been used to draw on the cave walls 221 00:13:58,525 --> 00:14:00,146 or for body painting. 222 00:14:02,732 --> 00:14:05,387 This suggests the people living here 223 00:14:05,525 --> 00:14:08,111 had high levels of communication, 224 00:14:08,249 --> 00:14:10,836 and perhaps even language. 225 00:14:17,043 --> 00:14:18,939 In the time period we're looking at, 226 00:14:19,077 --> 00:14:22,594 you see technology that's, that's advanced enough 227 00:14:22,732 --> 00:14:24,456 and requires enough planning 228 00:14:24,594 --> 00:14:26,836 that the technology would need to be taught. 229 00:14:28,353 --> 00:14:29,939 And it's, it's probably not something 230 00:14:30,077 --> 00:14:32,043 that could just be done visually, 231 00:14:32,180 --> 00:14:37,456 um, it would need to be done in words and expressed. 232 00:14:37,594 --> 00:14:39,698 So, um, I think it's that, 233 00:14:39,836 --> 00:14:42,008 it's that transmission of knowledge 234 00:14:42,146 --> 00:14:46,905 from one generation to the next, I think we see evidence of that, 235 00:14:47,043 --> 00:14:49,594 it really, really couldn't have happened without speech. 236 00:14:52,215 --> 00:14:56,318 [narrator] Language allowed humans to organize their society 237 00:14:56,456 --> 00:14:59,387 in a way no other creature was capable of. 238 00:15:04,353 --> 00:15:06,974 We can never know what they said to each other, 239 00:15:07,111 --> 00:15:09,974 but we might be able to get just a hint 240 00:15:10,111 --> 00:15:11,732 of what it sounded like. 241 00:15:14,767 --> 00:15:18,249 Two thousand kilometers north of Pinnacle Point 242 00:15:18,387 --> 00:15:21,077 lies a vast land of semi desert. 243 00:15:24,387 --> 00:15:27,008 [lively music] 244 00:15:33,387 --> 00:15:36,043 [chirping] 245 00:15:39,043 --> 00:15:41,387 [African tribal music] 246 00:15:42,560 --> 00:15:44,491 [indistinct chatter] 247 00:15:44,629 --> 00:15:48,594 This is the home of the San Bushmen of the Kalahari. 248 00:15:51,905 --> 00:15:54,387 And it's in them we might find a hint 249 00:15:54,525 --> 00:15:56,870 of the language of our forefathers. 250 00:15:57,008 --> 00:16:02,456 [speaking in native language] 251 00:16:02,594 --> 00:16:04,318 [speaking in native language] 252 00:16:04,456 --> 00:16:08,318 The language they're speaking is known as a click language. 253 00:16:08,456 --> 00:16:11,939 [speaking in native language] 254 00:16:13,043 --> 00:16:16,698 My name is Toma, me T-O Toma. 255 00:16:16,836 --> 00:16:20,387 We have four clicks in our language, 256 00:16:20,525 --> 00:16:23,939 I mean the first one is ka-ka... 257 00:16:24,077 --> 00:16:25,698 [Bertus] Ka. Ka. 258 00:16:26,284 --> 00:16:27,939 Ka. 259 00:16:28,077 --> 00:16:29,698 And the second one is ka... 260 00:16:29,836 --> 00:16:31,043 Ka. 261 00:16:31,180 --> 00:16:32,870 Ka-ka. 262 00:16:33,008 --> 00:16:36,422 And the third one is tut-tut-ka. 263 00:16:36,560 --> 00:16:38,146 Ka. 264 00:16:38,284 --> 00:16:43,111 And the fourth one is ka-ka, ka. 265 00:16:43,249 --> 00:16:44,318 [clicks tongue] [Bertus] Ka-ka. 266 00:16:44,456 --> 00:16:46,767 [speaking in native language] 267 00:16:46,905 --> 00:16:47,974 [narrator] There are many different 268 00:16:48,111 --> 00:16:50,870 - click languages in Africa -[baby coos] 269 00:16:51,008 --> 00:16:54,387 but 3,000 kilometers away in Tanzania 270 00:16:54,525 --> 00:16:56,663 there's a tribe who speak a click language 271 00:16:56,801 --> 00:17:00,284 so similar to the one spoken by the Namibian Bushmen 272 00:17:00,422 --> 00:17:03,353 that some scientists think they're linked. 273 00:17:04,215 --> 00:17:06,456 [speaking in native language] 274 00:17:06,594 --> 00:17:12,525 [chanting in native language] 275 00:17:12,663 --> 00:17:14,767 This is intriguing, 276 00:17:14,905 --> 00:17:17,077 because these two groups of people 277 00:17:17,215 --> 00:17:21,939 may not have been in contact for over 100,000 years. 278 00:17:23,698 --> 00:17:26,870 One explanation is that the clicks existed 279 00:17:27,008 --> 00:17:29,836 before these two tribes went their separate ways 280 00:17:29,974 --> 00:17:32,284 and are therefore an ancient element 281 00:17:32,422 --> 00:17:33,560 in human language. 282 00:17:33,698 --> 00:17:35,870 [speaking in native language] 283 00:17:36,870 --> 00:17:39,663 [baby cries] 284 00:17:39,801 --> 00:17:41,249 [speaking in native language] 285 00:17:41,387 --> 00:17:46,008 [speaking in native language] 286 00:17:50,146 --> 00:17:52,491 And it's possible that such a language 287 00:17:52,629 --> 00:17:55,387 may have given us a special advantage. 288 00:17:56,525 --> 00:17:57,939 When Bushmen hunt 289 00:17:58,077 --> 00:18:01,284 they sometimes do something called devoicing. 290 00:18:01,422 --> 00:18:03,836 [indistinct chatter] 291 00:18:03,974 --> 00:18:05,525 They stop using vowels 292 00:18:05,663 --> 00:18:08,732 and communicate only through their clicks. 293 00:18:08,870 --> 00:18:12,594 The idea is to make it hard for their prey to detect them. 294 00:18:12,732 --> 00:18:17,560 [speaking in native language] 295 00:18:17,698 --> 00:18:20,077 But the Bushmen can show us something else 296 00:18:20,215 --> 00:18:24,491 about what may have made our species so successful. 297 00:18:24,629 --> 00:18:26,698 By looking at how they hunt, 298 00:18:26,836 --> 00:18:28,836 we can learn how our bodies 299 00:18:28,974 --> 00:18:32,801 enabled us to become supreme predators. 300 00:18:32,939 --> 00:18:34,974 [lively music] 301 00:18:39,353 --> 00:18:43,387 The Bushmen use a very distinct hunting technique. 302 00:18:43,525 --> 00:18:45,939 It's called persistence hunting 303 00:18:46,077 --> 00:18:49,456 and is perhaps the most ancient method of catching prey. 304 00:18:55,974 --> 00:18:58,732 Their strategy is to track their target 305 00:18:58,870 --> 00:19:00,422 and then run it down 306 00:19:00,560 --> 00:19:03,629 until it collapses with exhaustion. 307 00:19:10,939 --> 00:19:14,698 Our species may not be able to outsprint an antelope, 308 00:19:14,836 --> 00:19:17,939 but we can outrun one over a long distance. 309 00:19:20,215 --> 00:19:22,043 So how do we do it? 310 00:19:26,111 --> 00:19:29,456 [rustling] 311 00:19:31,974 --> 00:19:36,732 Our first advantage is that we have lost all our fur, 312 00:19:36,870 --> 00:19:40,077 and we sweat from glands all over our bodies, 313 00:19:40,215 --> 00:19:41,491 allowing us to cool down 314 00:19:41,629 --> 00:19:44,043 much more efficiently than most animals. 315 00:19:47,215 --> 00:19:51,215 This is crucial, especially during persistence hunting, 316 00:19:51,353 --> 00:19:55,318 because most of our prey need to pant to cool down, 317 00:19:55,456 --> 00:19:57,767 which they can't do whilst running fast. 318 00:19:59,629 --> 00:20:01,836 So they are forced to stop, 319 00:20:01,974 --> 00:20:04,801 allowing the hunters to catch them. 320 00:20:04,939 --> 00:20:07,629 [calm music] 321 00:20:13,629 --> 00:20:15,732 And our efficient cooling system 322 00:20:15,870 --> 00:20:17,974 also means we can hunt in the day 323 00:20:18,111 --> 00:20:19,698 when the other big predators, 324 00:20:19,836 --> 00:20:23,215 the lions and the leopards, tend to stay away. 325 00:20:23,353 --> 00:20:26,560 [growls] 326 00:20:26,698 --> 00:20:30,318 They normally hunt at night to avoid overheating. 327 00:20:35,698 --> 00:20:38,525 And it's not just our ability to keep cool 328 00:20:38,663 --> 00:20:40,974 that makes us so good at distance running. 329 00:20:45,111 --> 00:20:48,353 We have long legs for the size of our bodies. 330 00:20:49,767 --> 00:20:52,456 And we have evolved a brilliant system of springs 331 00:20:52,594 --> 00:20:53,974 in the leg and foot 332 00:20:54,111 --> 00:20:57,008 which store and release energy when we're running. 333 00:20:59,111 --> 00:21:01,525 And there's one muscle that's fundamental 334 00:21:01,663 --> 00:21:04,491 to our ability to run for a long time. 335 00:21:04,629 --> 00:21:07,939 The gluteus maximus, or buttocks. 336 00:21:09,629 --> 00:21:12,284 It's this muscle that helps stabilize our bodies 337 00:21:12,422 --> 00:21:13,560 when we're running. 338 00:21:16,353 --> 00:21:18,629 These physical adaptations 339 00:21:18,767 --> 00:21:21,146 combined with our ability to communicate 340 00:21:21,284 --> 00:21:23,043 and our advanced technologies 341 00:21:23,180 --> 00:21:27,767 give us a hint of what made our ancestors so successful. 342 00:21:29,560 --> 00:21:33,077 From East Africa to the Cape in the South. 343 00:21:35,456 --> 00:21:37,663 But if this is our homeland, 344 00:21:37,801 --> 00:21:41,491 when and how did we leave Africa? 345 00:21:43,767 --> 00:21:46,560 [rustling] 346 00:21:46,698 --> 00:21:49,456 Until recently, all we had to go on 347 00:21:49,594 --> 00:21:52,318 was a sparse archaeological record, 348 00:21:53,560 --> 00:21:54,870 but new discoveries 349 00:21:55,008 --> 00:21:57,905 in one of the most exciting fields of science 350 00:21:58,043 --> 00:22:00,663 is unlocking the mystery, 351 00:22:00,801 --> 00:22:05,836 and amazingly the clues lie within each and every one of us. 352 00:22:07,146 --> 00:22:09,111 [light music] 353 00:22:09,249 --> 00:22:10,698 Buried in our bodies 354 00:22:10,836 --> 00:22:13,663 is an indelible record of our past, 355 00:22:13,801 --> 00:22:17,318 a story of our ancestors. 356 00:22:17,456 --> 00:22:20,732 Can this tell us how we left Africa? 357 00:22:24,111 --> 00:22:27,456 The secret lies in our DNA. 358 00:22:27,594 --> 00:22:29,836 Scientists are able to take samples 359 00:22:29,974 --> 00:22:33,801 of a special type of DNA that we all carry within us. 360 00:22:34,732 --> 00:22:37,456 It's called mitochondrial DNA 361 00:22:37,594 --> 00:22:40,560 and it's passed down from mothers to their children. 362 00:22:44,215 --> 00:22:45,422 But once in a while, 363 00:22:45,560 --> 00:22:48,249 something goes wrong with the copying process 364 00:22:48,387 --> 00:22:51,870 producing a random harmless mutation. 365 00:22:52,008 --> 00:22:55,422 These rare mutations enable scientists 366 00:22:55,560 --> 00:22:57,905 to build a global family tree. 367 00:23:05,422 --> 00:23:08,215 The tree is thickest at the bottom. 368 00:23:08,353 --> 00:23:11,180 This represents our roots in Africa 369 00:23:11,318 --> 00:23:14,456 where our species first emerged. 370 00:23:14,594 --> 00:23:17,318 And the branches at the top of the tree represent 371 00:23:17,456 --> 00:23:19,180 the DNA found in people 372 00:23:19,318 --> 00:23:21,594 throughout the rest of the world. 373 00:23:21,732 --> 00:23:24,491 Every single person outside of Africa 374 00:23:24,629 --> 00:23:26,905 can be placed on these branches. 375 00:23:29,629 --> 00:23:32,422 And in Cape Town, South Africa, 376 00:23:32,560 --> 00:23:36,629 is a man who spends his life working with DNA. 377 00:23:36,767 --> 00:23:38,387 [splashing] 378 00:23:38,525 --> 00:23:40,215 Africa's crucially important 379 00:23:40,353 --> 00:23:42,560 because as you can see on this tree 380 00:23:42,698 --> 00:23:46,387 the branches in Africa are the thickest and the densest 381 00:23:46,525 --> 00:23:49,387 and the thickest part of the trunk 382 00:23:49,525 --> 00:23:52,077 is where you look for the origins of humanity, 383 00:23:52,215 --> 00:23:55,594 and that trunk and the root is right here in Africa. 384 00:23:55,732 --> 00:23:57,905 [Ramesak] So the mother of all of humanity, 385 00:23:58,043 --> 00:24:02,732 a single African eve so to speak, is right here. 386 00:24:04,043 --> 00:24:06,180 [narrator] Extraordinary as it sounds, 387 00:24:06,318 --> 00:24:11,284 analysis of the data indicates that every person alive today 388 00:24:11,422 --> 00:24:14,180 shares a single common ancestor, 389 00:24:14,318 --> 00:24:19,077 a woman who lived in Africa over 100,000 years ago. 390 00:24:19,215 --> 00:24:22,525 She is right at the bottom of the tree. 391 00:24:24,180 --> 00:24:27,594 But there's an even more surprising revelation. 392 00:24:29,249 --> 00:24:31,422 When we put all of this information together 393 00:24:31,560 --> 00:24:33,629 mapping people from all parts of the world, 394 00:24:33,767 --> 00:24:36,215 what we are able to see is that there was probably 395 00:24:36,353 --> 00:24:39,284 a single migration route out of Africa 396 00:24:39,422 --> 00:24:42,801 and then out towards Asia and Europe. 397 00:24:42,939 --> 00:24:45,525 [narrator] Just one thin branch of the tree 398 00:24:45,663 --> 00:24:48,698 connects Africans to everyone else, 399 00:24:48,836 --> 00:24:53,146 which suggests amazingly that everyone outside of Africa 400 00:24:53,284 --> 00:24:57,008 descends from just one group who left the continent. 401 00:24:59,974 --> 00:25:03,767 And scientists can even estimate the size of this group. 402 00:25:03,905 --> 00:25:07,732 It may have been no more than a few hundred people strong. 403 00:25:11,422 --> 00:25:13,560 The rest of the world was populated 404 00:25:13,698 --> 00:25:17,456 by descendants of this tiny pioneering group. 405 00:25:19,525 --> 00:25:22,491 What's more if it was just one group 406 00:25:22,629 --> 00:25:27,077 it suggests they took only one route out of the continent. 407 00:25:29,180 --> 00:25:31,836 So which way did they go? 408 00:25:36,836 --> 00:25:38,870 [African tribal music] 409 00:25:41,077 --> 00:25:46,560 We can see from a map of Africa that there was no easy way out. 410 00:25:46,698 --> 00:25:48,629 The people of the sub-Sahara 411 00:25:48,767 --> 00:25:51,422 were essentially living on an island, 412 00:25:51,560 --> 00:25:57,525 cut off by oceans to the south, east, and west, 413 00:25:59,077 --> 00:26:02,456 and by an impassable desert to the north. 414 00:26:09,767 --> 00:26:13,767 The Sahara stretches the width of the continent, 415 00:26:13,905 --> 00:26:16,767 covering nine million square kilometers, 416 00:26:16,905 --> 00:26:18,905 it spans 11 countries. 417 00:26:23,870 --> 00:26:25,353 But surprisingly, 418 00:26:25,491 --> 00:26:29,629 a discovery on the other side of the desert in Israel 419 00:26:29,767 --> 00:26:31,905 promises to reveal vital clues 420 00:26:32,043 --> 00:26:35,284 about the human journey out of Africa. 421 00:26:38,146 --> 00:26:40,560 [chanting in native language] 422 00:26:55,905 --> 00:26:58,870 The discovery was made in the 1930's 423 00:26:59,008 --> 00:27:03,146 by the first female professor at Cambridge University. 424 00:27:04,767 --> 00:27:08,387 [chanting in native language] 425 00:27:08,525 --> 00:27:10,974 And what she found was staggering. 426 00:27:11,111 --> 00:27:13,111 [chanting in native language] 427 00:27:13,249 --> 00:27:15,387 [calm music] 428 00:27:22,111 --> 00:27:26,456 Archaeologist Dorothy Garrod was leading an excavation 429 00:27:26,594 --> 00:27:28,663 on the slopes of Mount Carmel. 430 00:27:30,801 --> 00:27:33,801 Outside a cave known as Skhul, 431 00:27:33,939 --> 00:27:37,387 they uncovered stone tools similar to those found 432 00:27:37,525 --> 00:27:40,422 at Pinnacle Point in South Africa. 433 00:27:42,870 --> 00:27:45,284 But even greater treasures were found 434 00:27:45,422 --> 00:27:47,698 when they dug one and a half meters down 435 00:27:47,836 --> 00:27:51,387 almost to the bedrock outside the caves. 436 00:27:51,525 --> 00:27:55,387 The remains of ten human skeletons. 437 00:27:58,008 --> 00:28:00,525 After painstakingly chiseling out the blocks 438 00:28:00,663 --> 00:28:02,836 in which the remains were entombed, 439 00:28:02,974 --> 00:28:05,698 Garrod's team encased them in plaster 440 00:28:05,836 --> 00:28:08,594 and carefully lowered them to the valley floor 441 00:28:08,732 --> 00:28:10,767 to be taken for conservation. 442 00:28:10,905 --> 00:28:12,939 [ominous music] 443 00:28:16,870 --> 00:28:19,905 Today, they lie in the Rockefeller Museum 444 00:28:20,043 --> 00:28:23,284 in Jerusalem in the exact positions 445 00:28:23,422 --> 00:28:25,974 in which they were found. 446 00:28:26,111 --> 00:28:30,111 These bodies have been carefully buried 447 00:28:30,249 --> 00:28:35,043 and some were laid to rest with grave goods. 448 00:28:35,180 --> 00:28:40,491 One was found clasping the jaw of a wild boar. 449 00:28:40,629 --> 00:28:44,594 It seems likely they were buried this way for a reason 450 00:28:44,732 --> 00:28:47,836 and that they had a belief in the afterlife. 451 00:28:49,560 --> 00:28:52,698 It's the first time in the human story 452 00:28:52,836 --> 00:28:56,801 we see clear evidence for supernatural belief. 453 00:28:58,525 --> 00:29:02,215 These were fully modern humans, 454 00:29:02,353 --> 00:29:07,905 and their bones have been dated to around 100,000 years ago. 455 00:29:11,594 --> 00:29:13,836 But how did they end up here 456 00:29:13,974 --> 00:29:17,043 on the far side of the deadly Sahara? 457 00:29:17,180 --> 00:29:20,560 [wind gusting] 458 00:29:20,698 --> 00:29:24,249 There's another new branch of science that could help. 459 00:29:24,387 --> 00:29:25,836 Climate modelling. 460 00:29:28,870 --> 00:29:30,939 We've commissioned some of the world's 461 00:29:31,077 --> 00:29:34,180 top climate scientists to work out the climate 462 00:29:34,318 --> 00:29:36,525 in every part of the world, 463 00:29:36,663 --> 00:29:39,905 but not for the present, for the past. 464 00:29:46,387 --> 00:29:48,629 For months, simulated models 465 00:29:48,767 --> 00:29:51,180 were processed by super computers 466 00:29:51,318 --> 00:29:54,732 and have revealed details of changes in temperature, 467 00:29:54,870 --> 00:29:57,974 rain fall, sea level and vegetation. 468 00:29:58,111 --> 00:29:59,767 [thunder rumbling] 469 00:29:59,905 --> 00:30:02,629 There have been some fairly dramatic changes in climate 470 00:30:02,767 --> 00:30:05,870 over the last 100,000 years or so, so, 471 00:30:06,008 --> 00:30:08,249 um, and these would have had a big impact 472 00:30:08,387 --> 00:30:12,284 on modern humans in terms of how they live, 473 00:30:12,422 --> 00:30:13,629 where they can live, 474 00:30:13,767 --> 00:30:16,353 where they can migrate to and so in that sense, 475 00:30:16,491 --> 00:30:18,560 it's very important to understand the climate 476 00:30:18,698 --> 00:30:21,353 over the whole of the globe at several points in the past. 477 00:30:22,698 --> 00:30:24,215 [narrator] So what does this tell us 478 00:30:24,353 --> 00:30:27,698 about how we left Africa? 479 00:30:27,836 --> 00:30:30,870 The region of North Africa, the Sahara and the Middle East, 480 00:30:31,008 --> 00:30:34,111 you think of at the moment as being very dry, 481 00:30:34,249 --> 00:30:36,594 um, you think of deserts and sand 482 00:30:36,732 --> 00:30:38,836 and very hot and arid basically, 483 00:30:38,974 --> 00:30:41,043 but 125,000 years ago 484 00:30:41,180 --> 00:30:43,353 it was actually fairly, fairly different to that. 485 00:30:43,491 --> 00:30:45,698 [Joy] And if we run the climate model forward through time 486 00:30:45,836 --> 00:30:48,767 from 140,000 years ago, 487 00:30:48,905 --> 00:30:52,180 you can see in particular the region around the Sahara 488 00:30:52,318 --> 00:30:53,387 gets a lot more green 489 00:30:53,525 --> 00:30:56,387 when you get to about 125,000 years ago. 490 00:30:56,525 --> 00:30:58,422 [Joy] You can see a kind of a northward extension 491 00:30:58,560 --> 00:31:01,422 of this green bit into the Sahara. 492 00:31:01,560 --> 00:31:02,939 It was a lot wetter, 493 00:31:03,077 --> 00:31:06,284 there were rivers and lakes and wetlands 494 00:31:06,422 --> 00:31:07,801 and also the surface 495 00:31:07,939 --> 00:31:10,663 was actually quite well-vegetated. 496 00:31:10,801 --> 00:31:11,801 This would probably have meant 497 00:31:11,939 --> 00:31:14,663 that animals and humans could have, 498 00:31:14,801 --> 00:31:16,215 could have followed this as well. 499 00:31:16,353 --> 00:31:20,491 [chanting in native language] 500 00:31:20,629 --> 00:31:24,146 [narrator] So around 125,000 years ago, 501 00:31:24,284 --> 00:31:26,353 the climate radically changed 502 00:31:26,491 --> 00:31:28,353 and the biggest, driest 503 00:31:28,491 --> 00:31:32,594 most impassable desert in the world briefly blossomed. 504 00:31:37,353 --> 00:31:41,663 For a few thousand years even the massive Sahara Desert 505 00:31:41,801 --> 00:31:44,560 would have looked more like the East African plains. 506 00:31:50,491 --> 00:31:54,732 A welcoming home for animals and our ancestors. 507 00:31:54,870 --> 00:31:57,284 [rumbling] 508 00:32:01,387 --> 00:32:03,387 [rasping] 509 00:32:12,663 --> 00:32:14,939 [narrator] Gradually, humans could have followed 510 00:32:15,077 --> 00:32:16,836 the game further north. 511 00:32:27,698 --> 00:32:30,629 Eventually, some arrived in Israel 512 00:32:30,767 --> 00:32:33,594 where they lived for many thousands of years. 513 00:32:34,525 --> 00:32:37,629 [chanting in native language] 514 00:32:43,732 --> 00:32:46,043 So is that the mystery solved? 515 00:32:46,180 --> 00:32:49,284 Is this how we left Africa? 516 00:32:50,974 --> 00:32:53,456 Well, these are certainly the oldest remains 517 00:32:53,594 --> 00:32:57,353 of our species found anywhere outside of Africa, 518 00:32:57,491 --> 00:32:59,974 but were they our ancestors? 519 00:33:00,111 --> 00:33:01,939 It seems not. 520 00:33:04,870 --> 00:33:07,801 The astonishing finds in the Mount Carmel caves 521 00:33:07,939 --> 00:33:11,422 are the end of this archaeological trail. 522 00:33:11,560 --> 00:33:14,560 No other evidence has been found anywhere 523 00:33:14,698 --> 00:33:19,525 to suggest humans survived here or continued the journey. 524 00:33:21,698 --> 00:33:24,732 The story of this particular pioneering group 525 00:33:24,870 --> 00:33:28,456 does not seem to have a happy ending. 526 00:33:28,594 --> 00:33:32,698 And once again, it may all be down to the climate. 527 00:33:34,077 --> 00:33:36,077 [ominous music] 528 00:33:38,008 --> 00:33:39,836 [Joy] We can run the climate model forward again 529 00:33:39,974 --> 00:33:43,663 from about 125,000 years ago and see what happens. 530 00:33:46,387 --> 00:33:49,111 [Joy] And what happens over North Africa 531 00:33:49,249 --> 00:33:50,629 and the Middle East is that 532 00:33:50,767 --> 00:33:53,249 as you can see all that green respectively got 533 00:33:53,387 --> 00:33:54,629 a lot more drier, a lot more arid, 534 00:33:54,767 --> 00:33:56,249 there's a lot less rain fall occurring, 535 00:33:56,387 --> 00:33:59,387 and so, the vegetation has been replaced by desert. 536 00:33:59,525 --> 00:34:01,905 [Joy] There would have been less water available 537 00:34:02,043 --> 00:34:03,698 and so in effect it would be a, 538 00:34:03,836 --> 00:34:06,008 a lot harder place for people to have lived, 539 00:34:06,146 --> 00:34:08,146 and certain regions would have been 540 00:34:08,284 --> 00:34:10,008 almost completely uninhabitable. 541 00:34:11,905 --> 00:34:14,215 [narrator] This expansion of the desert 542 00:34:14,353 --> 00:34:15,663 may have been disastrous 543 00:34:15,801 --> 00:34:18,525 for the people who lived in the Skhul Caves. 544 00:34:20,870 --> 00:34:24,525 If the animals that they hunted for food disappeared, 545 00:34:24,663 --> 00:34:27,456 then starvation would have become a reality. 546 00:34:32,043 --> 00:34:33,525 And at the same time, 547 00:34:33,663 --> 00:34:36,870 the route across the Sahara back to Africa 548 00:34:37,008 --> 00:34:38,318 would have been shut. 549 00:34:47,387 --> 00:34:49,491 It seems that these people, 550 00:34:49,629 --> 00:34:52,870 the first of our kind known to have left Africa, 551 00:34:53,008 --> 00:34:54,767 simply died out. 552 00:35:05,043 --> 00:35:08,422 So if these people are not our forebears, 553 00:35:08,560 --> 00:35:12,629 what route did our ancestors take out of Africa? 554 00:35:18,111 --> 00:35:21,560 We know the Sahara had turned back to desert, 555 00:35:21,698 --> 00:35:25,525 so we can pretty confidently rule out a northerly exit route, 556 00:35:26,905 --> 00:35:31,077 which leaves just one remaining option, the sea. 557 00:35:32,560 --> 00:35:34,939 So what would be the most likely sea crossing 558 00:35:35,077 --> 00:35:38,318 for a group of early African hunter gatherers? 559 00:35:40,146 --> 00:35:42,836 One option is the Red Sea. 560 00:35:42,974 --> 00:35:47,594 It separates Africa from Arabia and at its narrowest point, 561 00:35:47,732 --> 00:35:50,008 it is only 30 kilometers wide. 562 00:35:51,525 --> 00:35:54,905 [chanting in native language] 563 00:35:55,043 --> 00:35:59,456 The Arabic name for this place is the Bab el Mandeb 564 00:35:59,594 --> 00:36:03,387 which is usually translated as the "Gate of Grief." 565 00:36:04,249 --> 00:36:05,939 But new research suggests 566 00:36:06,077 --> 00:36:08,836 that in an ancient language of Southern Arabia 567 00:36:08,974 --> 00:36:14,698 a better translation would be the "Gateway of the Crossing." 568 00:36:14,836 --> 00:36:18,732 Could this be a clue as to how we left Africa? 569 00:36:20,353 --> 00:36:22,801 [thunder rumbling] 570 00:36:22,939 --> 00:36:26,111 Whilst 30 kilometers may not sound like much, 571 00:36:26,249 --> 00:36:27,525 it's a huge barrier 572 00:36:27,663 --> 00:36:30,732 if you don't have a sea going vessel. 573 00:36:30,870 --> 00:36:34,732 So how might people have made the crossing? 574 00:36:34,870 --> 00:36:37,077 Ironically, it may have been down 575 00:36:37,215 --> 00:36:39,318 to the same change in climate 576 00:36:39,456 --> 00:36:41,836 that trapped the people in Israel. 577 00:36:49,008 --> 00:36:50,801 At the same time as the Sahara 578 00:36:50,939 --> 00:36:52,732 is beginning to dry out in, in north Africa, 579 00:36:52,870 --> 00:36:54,836 it's forming large deserts again, 580 00:36:54,974 --> 00:36:57,146 we're heading into a glaciation, 581 00:36:57,284 --> 00:36:58,732 so that means a formation 582 00:36:58,870 --> 00:37:01,560 of big ice sheets over north America and Europe 583 00:37:01,698 --> 00:37:04,836 which lock up water from the ocean 584 00:37:04,974 --> 00:37:08,422 and this means a drop in sea level occurred, 585 00:37:08,560 --> 00:37:11,698 and we can run the model forward through time to see this. 586 00:37:11,836 --> 00:37:14,043 [Joy] And if we look in the Red Sea region, 587 00:37:14,180 --> 00:37:16,456 we can see that a lot of new land 588 00:37:16,594 --> 00:37:18,939 is being exposed because of this. 589 00:37:19,077 --> 00:37:22,353 And when you get to about 70,000 years ago, 590 00:37:22,491 --> 00:37:25,456 you can see that there's a lot of new land around here, 591 00:37:25,594 --> 00:37:28,870 and that the distance, um, to cross from Africa 592 00:37:29,008 --> 00:37:32,456 over to the Arabian Peninsula by sea is reduced greatly. 593 00:37:33,974 --> 00:37:36,836 [narrator] In fact, this drop-in sea levels meant 594 00:37:36,974 --> 00:37:39,629 that the shortest distance across the Red Sea 595 00:37:39,767 --> 00:37:42,629 fell to just 11 kilometers. 596 00:37:44,008 --> 00:37:46,939 Was this the opportunity people needed 597 00:37:47,077 --> 00:37:50,491 to take the leap from Africa to the rest of the world? 598 00:37:50,629 --> 00:37:53,767 [chanting in native language] 599 00:38:00,767 --> 00:38:03,974 They may have had good reason to make the journey. 600 00:38:04,111 --> 00:38:07,387 As the climate changed, planes dried out 601 00:38:07,525 --> 00:38:09,905 and the sea became more salty. 602 00:38:10,043 --> 00:38:12,663 Their sources of food were under threat. 603 00:38:15,732 --> 00:38:19,111 The pressure to find new lands and opportunities 604 00:38:19,249 --> 00:38:22,870 may have made a starving population risk everything 605 00:38:23,008 --> 00:38:24,077 and make the crossing. 606 00:38:24,215 --> 00:38:27,318 [rumbling] 607 00:38:27,456 --> 00:38:29,560 A journey that could have happened 608 00:38:29,698 --> 00:38:33,077 sometime around 70,000 years ago. 609 00:38:37,146 --> 00:38:40,422 But if the crossing itself wasn't tough enough 610 00:38:40,560 --> 00:38:42,249 what awaited them on the other side 611 00:38:42,387 --> 00:38:44,801 seems even more treacherous. 612 00:38:45,939 --> 00:38:47,974 [calm music] 613 00:38:51,594 --> 00:38:55,456 Today, Arabia is a brutal desert, 614 00:38:55,594 --> 00:38:57,974 not dissimilar to how it would have been at the time 615 00:38:58,111 --> 00:38:59,974 of this potential crossing. 616 00:39:03,043 --> 00:39:05,870 Temperatures in the heart of the Arabian Desert 617 00:39:06,008 --> 00:39:08,870 reach 50 degrees Celsius, 618 00:39:09,008 --> 00:39:12,008 it's one of the hottest places on the planet. 619 00:39:14,801 --> 00:39:19,560 Did our ancestors really manage to survive in this place? 620 00:39:19,698 --> 00:39:21,836 It sounds unlikely. 621 00:39:27,077 --> 00:39:29,525 [tense music] 622 00:39:32,215 --> 00:39:37,249 But Dr. Jeff Rose is not one to be put off by a challenge, 623 00:39:37,387 --> 00:39:39,870 even the challenge of finding evidence 624 00:39:40,008 --> 00:39:41,801 in such a forbidding place. 625 00:39:45,698 --> 00:39:48,180 He's one of just a few archaeologists 626 00:39:48,318 --> 00:39:51,836 to search for clues to our ancient past in this region, 627 00:39:53,974 --> 00:39:56,698 and he believes that this dead place 628 00:39:56,836 --> 00:39:59,663 was once alive with our ancestors. 629 00:39:59,801 --> 00:40:02,284 [engine revving] 630 00:40:02,422 --> 00:40:05,008 To test his claims, we took him on a route 631 00:40:05,146 --> 00:40:08,353 through the Arabian Desert which he'd never seen before 632 00:40:08,491 --> 00:40:13,629 and asked him if he could find any signs of ancient life. 633 00:40:13,767 --> 00:40:15,594 [Jeffrey] It's actually quite a special location. 634 00:40:15,732 --> 00:40:17,456 If you look around you see all these black rocks 635 00:40:17,594 --> 00:40:19,215 that are lying across the surface, 636 00:40:19,353 --> 00:40:20,594 well, they aren't really rocks, 637 00:40:20,732 --> 00:40:23,801 they're all ancient stone tools made by early humans. 638 00:40:25,008 --> 00:40:26,456 [Jeffrey] Well, I've picked up a few just, 639 00:40:26,594 --> 00:40:29,456 just lying on the surface here and these are called cores, 640 00:40:29,594 --> 00:40:30,594 so these are the pebbles 641 00:40:30,732 --> 00:40:32,008 they would have held in this hand, 642 00:40:32,146 --> 00:40:33,629 they would have had a harder stone in this hand 643 00:40:33,767 --> 00:40:35,870 and they would have knocked flakes off of, off of this, 644 00:40:36,008 --> 00:40:38,905 which would have then, then been turned into tools, 645 00:40:39,043 --> 00:40:40,905 and these particular cores are called blade core, 646 00:40:41,043 --> 00:40:43,456 so it's, it's very specific technology 647 00:40:43,594 --> 00:40:46,387 where they're trying to remove these long, thin blanks 648 00:40:46,525 --> 00:40:49,146 which would then be turned into scrapers or arrowheads 649 00:40:49,284 --> 00:40:50,594 or something like that. 650 00:40:52,732 --> 00:40:54,594 And this is, this is a particularly interesting one 651 00:40:54,732 --> 00:40:56,318 because we can see they've, 652 00:40:56,456 --> 00:40:58,698 they've removed flakes here and here 653 00:40:58,836 --> 00:41:00,836 and then they got themselves into trouble, they hit it here, 654 00:41:00,974 --> 00:41:02,284 they didn't hit it quite hard enough 655 00:41:02,422 --> 00:41:03,525 and you get what's called a hinge fracture 656 00:41:03,663 --> 00:41:05,215 running along this edge here, 657 00:41:05,353 --> 00:41:06,387 and it's a mistake. 658 00:41:06,525 --> 00:41:07,870 [Jeffrey] So they probably just said "ah" 659 00:41:08,008 --> 00:41:09,594 and threw it over the side and picked up another piece 660 00:41:09,732 --> 00:41:10,732 and tried again. 661 00:41:11,594 --> 00:41:13,284 It's everywhere in Arabia. 662 00:41:14,732 --> 00:41:17,318 [narrator] And that's why they litter the ground. 663 00:41:17,456 --> 00:41:20,560 This place was a stone tool factory. 664 00:41:21,387 --> 00:41:23,525 This and, and the entire plateau 665 00:41:23,663 --> 00:41:25,215 that goes on for hundreds of kilometers 666 00:41:25,353 --> 00:41:27,732 to both the east and the west would have been a special place, 667 00:41:27,870 --> 00:41:30,146 because this raw material is everywhere. 668 00:41:30,284 --> 00:41:32,422 [Jeffrey] Raw material would have been as important to them 669 00:41:32,560 --> 00:41:33,939 as oil is to us today. 670 00:41:34,077 --> 00:41:36,767 They absolutely needed it to survive, to make their tools, 671 00:41:36,905 --> 00:41:41,974 to hunt, to fish, to skin hides, to make clothing, 672 00:41:42,111 --> 00:41:44,974 to make structures, to get shelter from the sun, 673 00:41:45,111 --> 00:41:46,698 so it was absolutely essential. 674 00:41:46,836 --> 00:41:49,905 [narrator] But who were the people who left these tools? 675 00:41:50,043 --> 00:41:51,732 Could they really be anything to do 676 00:41:51,870 --> 00:41:56,387 with a crossing of the Red Sea around 70,000 years ago? 677 00:41:56,525 --> 00:41:57,698 Everything is lying on the surface 678 00:41:57,836 --> 00:41:59,870 and surface sites can't really be dated 679 00:42:00,008 --> 00:42:01,215 using traditional methods. 680 00:42:01,353 --> 00:42:02,387 However, we can say 681 00:42:02,525 --> 00:42:04,180 based on the technology that we see here, 682 00:42:04,318 --> 00:42:06,594 this very specific blade technology, 683 00:42:06,732 --> 00:42:08,077 and there is a site dated in Yemen 684 00:42:08,215 --> 00:42:10,836 to about 70,000 years ago with the identical technology 685 00:42:10,974 --> 00:42:12,939 and then another site which we have found over, 686 00:42:13,077 --> 00:42:15,629 just over those mountains dated to about 12,000 years ago, 687 00:42:15,767 --> 00:42:17,353 so we can put it somewhere in that range, 688 00:42:17,491 --> 00:42:19,836 between 70,000 and 12,000 years ago. 689 00:42:22,905 --> 00:42:25,353 [narrator]But how could anyone have survived 690 00:42:25,491 --> 00:42:27,456 in this parched landscape? 691 00:42:29,456 --> 00:42:31,629 [calm music] 692 00:42:41,353 --> 00:42:44,456 Jeff believes the answer could lie a few miles 693 00:42:44,594 --> 00:42:46,663 from the stone tool factory. 694 00:42:48,215 --> 00:42:51,353 Within a short distance the desert undergoes 695 00:42:51,491 --> 00:42:53,629 a remarkable transformation. 696 00:42:54,974 --> 00:42:56,974 [tranquil music] 697 00:43:03,249 --> 00:43:05,318 [mooing] 698 00:43:08,043 --> 00:43:09,594 Apart from the camels, 699 00:43:09,732 --> 00:43:13,043 it's hard to believe that this is still Arabia. 700 00:43:15,974 --> 00:43:18,249 This is the fertile Wadi Darbat 701 00:43:18,387 --> 00:43:20,801 in the Dhofar mountains of Oman. 702 00:43:28,594 --> 00:43:31,767 It sits on the edge of a very active weather system 703 00:43:31,905 --> 00:43:34,077 which forms out in the Indian Ocean. 704 00:43:37,180 --> 00:43:39,594 [thunder crashes] 705 00:43:43,698 --> 00:43:45,767 The system's defining feature 706 00:43:45,905 --> 00:43:48,905 is the monsoon which blows in every summer. 707 00:43:49,043 --> 00:43:51,077 [thunder rumbling] 708 00:43:58,215 --> 00:44:00,043 With it comes the rain, 709 00:44:00,180 --> 00:44:03,801 which makes this place so lush and green. 710 00:44:15,353 --> 00:44:18,663 [mooing] 711 00:44:18,801 --> 00:44:22,491 And it could be that this simple accident of climate 712 00:44:22,629 --> 00:44:26,698 is absolutely key to our human journey, 713 00:44:26,836 --> 00:44:29,284 because it may have allowed our ancestors 714 00:44:29,422 --> 00:44:31,491 to establish a crucial foothold 715 00:44:31,629 --> 00:44:34,801 in this otherwise inhospitable new world. 716 00:44:38,525 --> 00:44:41,146 As an oasis in the middle of the desert, 717 00:44:41,284 --> 00:44:44,525 this may have been a refuge for some of our ancestors 718 00:44:44,663 --> 00:44:47,698 through the worst of the driest climate phases. 719 00:44:50,008 --> 00:44:52,180 But on either side of this refuge 720 00:44:52,318 --> 00:44:55,594 the desert still stretched for hundreds of miles. 721 00:44:56,387 --> 00:44:58,180 So how did these pioneers 722 00:44:58,318 --> 00:45:01,560 manage to move on through Arabia? 723 00:45:14,215 --> 00:45:16,387 [engine rumbling] 724 00:45:21,043 --> 00:45:23,146 If they really came this way, 725 00:45:23,284 --> 00:45:26,456 our ancestors must have found a source of water 726 00:45:26,594 --> 00:45:30,043 not only in Wadi Darbat but further east. 727 00:45:34,387 --> 00:45:36,318 The clue to how they did it 728 00:45:36,456 --> 00:45:38,836 may lie not in the Arabian Desert 729 00:45:38,974 --> 00:45:42,215 but under the waves of the Indian Ocean, 730 00:45:42,353 --> 00:45:43,870 because below this boat 731 00:45:44,008 --> 00:45:46,698 is a hidden source of fresh water. 732 00:45:49,836 --> 00:45:52,180 Seventy thousand years ago, 733 00:45:52,318 --> 00:45:56,043 the Arabian coastline looked very different to today. 734 00:45:57,491 --> 00:45:59,905 When our ancestors first saw it, 735 00:46:00,043 --> 00:46:01,629 sea levels were lower 736 00:46:01,767 --> 00:46:05,629 and what is now sea was then land. 737 00:46:05,767 --> 00:46:10,353 Crucially, the coast was dotted with springs of fresh water. 738 00:46:11,767 --> 00:46:14,318 So if our ancestors came this way, 739 00:46:14,456 --> 00:46:17,422 they could have found the lifeline. 740 00:46:17,560 --> 00:46:21,008 A fertile land of fresh water lakes and rivers, 741 00:46:21,146 --> 00:46:25,767 leading to what is today the Persian Gulf. 742 00:46:25,905 --> 00:46:28,422 The Persian Gulf is probably one of the most important places 743 00:46:28,560 --> 00:46:29,698 in the ancient world, 744 00:46:29,836 --> 00:46:31,836 because it's the shallowest inland sea in the world, 745 00:46:31,974 --> 00:46:33,008 it's only about 40 meters deep, 746 00:46:33,146 --> 00:46:34,629 so when that sea level was lower, 747 00:46:34,767 --> 00:46:37,249 the entire area was this exposed flood plain 748 00:46:37,387 --> 00:46:39,284 and all those drainage systems around Arabia 749 00:46:39,422 --> 00:46:41,111 that are coming from the Zagros Mountains, 750 00:46:41,249 --> 00:46:43,525 the Torus Mountains trapped beneath Arabia itself, 751 00:46:43,663 --> 00:46:46,594 flow into the gulf and they come bubbling up in the surface. 752 00:46:46,732 --> 00:46:49,249 So in ancient times you have lakes, estuaries, 753 00:46:49,387 --> 00:46:50,560 fresh water rivers, 754 00:46:50,698 --> 00:46:52,318 and only when the sea level was lower 755 00:46:52,456 --> 00:46:53,801 would it have been available, 756 00:46:53,939 --> 00:46:56,146 so it really shows why that coastline was so important 757 00:46:56,284 --> 00:46:58,387 for the early humans moving out of Africa. 758 00:46:59,456 --> 00:47:01,698 [chanting in native language] 759 00:47:03,146 --> 00:47:05,077 [narrator] The springs of fresh water 760 00:47:05,215 --> 00:47:06,767 along the coast of Arabia 761 00:47:06,905 --> 00:47:10,905 could have provided those early pioneers with water, 762 00:47:11,043 --> 00:47:12,974 the sea offered food 763 00:47:13,111 --> 00:47:14,767 and the desert gave them tools 764 00:47:14,905 --> 00:47:18,077 to survive the great journey to the Persian Gulf. 765 00:47:19,594 --> 00:47:21,801 [chanting in native language] 766 00:47:25,180 --> 00:47:27,318 And there's one final clue 767 00:47:27,456 --> 00:47:30,836 to how significant this place could be. 768 00:47:30,974 --> 00:47:34,422 When an early civilization grew up in this region, 769 00:47:34,560 --> 00:47:36,422 its people gave a name 770 00:47:36,560 --> 00:47:39,905 to the type of landscape they lived in. 771 00:47:40,043 --> 00:47:42,698 [Jeffrey] It was everything, it was paradise. 772 00:47:42,836 --> 00:47:44,767 In fact, the name for it by the people living 773 00:47:44,905 --> 00:47:47,008 along the northern shoreline was Eden. 774 00:47:49,525 --> 00:47:51,353 [narrator] It may be a coincidence, 775 00:47:51,491 --> 00:47:54,353 but this is the same word used in the bible 776 00:47:54,491 --> 00:47:56,525 for an earthly paradise. 777 00:47:57,974 --> 00:48:01,043 But it may well have been that from this Eden, 778 00:48:01,180 --> 00:48:03,043 humans gradually spread out 779 00:48:03,180 --> 00:48:07,387 in all directions eventually to Europe, 780 00:48:07,525 --> 00:48:12,008 Australia, Asia, and the Americas. 781 00:48:12,146 --> 00:48:15,387 When and how did they make these journeys? 782 00:48:15,525 --> 00:48:19,801 And how did the experience transform our ancestors 783 00:48:19,939 --> 00:48:24,077 and make us into the people we are today? 784 00:48:24,215 --> 00:48:27,974 These are the questions we'll seek to answer 785 00:48:28,111 --> 00:48:30,043 in the Human Journey. 786 00:48:31,008 --> 00:48:33,008 [closing theme music]