1 00:00:00,966 --> 00:00:03,600 ♪ ♪ 2 00:00:08,966 --> 00:00:12,300 KIRK JOHNSON: White Sands National Park, New Mexico... 3 00:00:14,400 --> 00:00:18,876 {\an1}A vast, open desert that holds clues to a lost past. 4 00:00:18,900 --> 00:00:20,109 DAVID BUSTOS: At White Sands, 5 00:00:20,133 --> 00:00:22,742 all good stories sort of begin with a Bigfoot. 6 00:00:22,766 --> 00:00:28,909 {\an8}JOHNSON: Footprints dating all the way back to the last Ice Age. 7 00:00:28,933 --> 00:00:32,009 All these circular things are fossil footprints. 8 00:00:32,033 --> 00:00:33,609 JOHNSON: That's amazing. 9 00:00:33,633 --> 00:00:35,309 ♪ ♪ 10 00:00:35,333 --> 00:00:36,876 JOHNSON: Mammoths over 13 feet tall. 11 00:00:36,900 --> 00:00:38,209 (mammoth grunting) 12 00:00:38,233 --> 00:00:41,576 Dire wolves, camels, 13 00:00:41,600 --> 00:00:43,776 {\an1}and enormous ground sloths 14 00:00:43,800 --> 00:00:48,142 {\an1}that roamed North America thousands of years ago. 15 00:00:48,166 --> 00:00:50,909 White Sands has so many hidden treasures. 16 00:00:50,933 --> 00:00:52,242 There's all these trackways here, 17 00:00:52,266 --> 00:00:53,876 it's just such an incredible discovery. 18 00:00:53,900 --> 00:00:55,942 ♪ ♪ 19 00:00:55,966 --> 00:00:57,842 JOHNSON: Alongside them, 20 00:00:57,866 --> 00:01:00,476 {\an1}something even more astounding. 21 00:01:00,500 --> 00:01:02,176 That is a human footprint. 22 00:01:02,200 --> 00:01:03,209 {\an1}Yeah, so there's 23 00:01:03,233 --> 00:01:04,210 {\an1}a human footprint right there. 24 00:01:04,234 --> 00:01:06,642 (laughing): Wow. 25 00:01:06,666 --> 00:01:08,409 JOHNSON: Ancient human journeys 26 00:01:08,433 --> 00:01:11,409 {\an1}printed on the landscape. 27 00:01:11,433 --> 00:01:13,676 {\an1}When you make tracks in sand, 28 00:01:13,700 --> 00:01:15,242 they just blow away. 29 00:01:15,266 --> 00:01:16,842 {\an1}When you make tracks in a place like this, 30 00:01:16,866 --> 00:01:18,576 where the chemistry is just right, 31 00:01:18,600 --> 00:01:21,542 the tracks can last forever. 32 00:01:21,566 --> 00:01:24,842 (voiceover): Now a team of experts is investigating 33 00:01:24,866 --> 00:01:30,209 {\an1}how these remarkable tracks could shed new light 34 00:01:30,233 --> 00:01:32,042 {\an1}on life in the Ice Age. 35 00:01:32,066 --> 00:01:33,909 {\an8}MATTHEW BENNETT: There's a double trail. 36 00:01:33,933 --> 00:01:36,576 {\an8}Somebody going this way, and somebody going that way. 37 00:01:36,600 --> 00:01:39,309 {\an8}JOHNSON: Wow, that is really incredible. 38 00:01:39,333 --> 00:01:40,909 {\an8}(voiceover): How long ago were they made? 39 00:01:40,933 --> 00:01:42,542 KATHLEEN SPRINGER: That's amazing. 40 00:01:42,566 --> 00:01:44,076 {\an3}MAN: Yeah. 41 00:01:44,100 --> 00:01:45,976 SPRINGER: The Ice Age megafauna went extinct 42 00:01:46,000 --> 00:01:47,909 {\an1}about 11,500 years ago. 43 00:01:47,933 --> 00:01:50,509 {\an1}So they're at least that old. 44 00:01:50,533 --> 00:01:51,576 {\an1}How much older than that 45 00:01:51,600 --> 00:01:53,776 {\an1}is really anyone's guess at this point. 46 00:01:53,800 --> 00:01:55,576 {\an8}JOHNSON: Could they provide new information about 47 00:01:55,600 --> 00:01:58,376 {\an8}early peoples of the Americas? 48 00:01:58,400 --> 00:02:02,242 It really does put our feet prints 49 00:02:02,266 --> 00:02:04,376 {\an7}firmly into the past here in North America. 50 00:02:04,400 --> 00:02:05,542 {\an8}KIM CHARLIE: Here's our proof. 51 00:02:05,566 --> 00:02:08,676 Footprints, footprints of our ancestors. 52 00:02:08,700 --> 00:02:10,442 ♪ ♪ 53 00:02:10,466 --> 00:02:12,842 JOHNSON: Can the secrets of these ancient footprints 54 00:02:12,866 --> 00:02:15,209 {\an1}help answer the questions 55 00:02:15,233 --> 00:02:19,542 {\an1}when and how did humans first arrive in North America? 56 00:02:19,566 --> 00:02:21,209 ♪ ♪ 57 00:02:21,233 --> 00:02:24,109 {\an1}"Ice Age Footprints"... 58 00:02:24,133 --> 00:02:27,300 Right now on "NOVA." 59 00:02:28,633 --> 00:02:32,700 ♪ ♪ 60 00:02:50,800 --> 00:02:52,942 JOHNSON: The dazzling dunes of 61 00:02:52,966 --> 00:02:56,209 {\an1}White Sands National Park. 62 00:02:56,233 --> 00:02:59,309 {\an1}Sand as bright as fresh snow. 63 00:02:59,333 --> 00:03:04,566 ♪ ♪ 64 00:03:05,700 --> 00:03:09,709 But hidden within this landscape 65 00:03:09,733 --> 00:03:14,176 {\an7}are traces of an ancient story 66 00:03:14,200 --> 00:03:19,776 {\an7}dating all the way back to the last Ice Age. 67 00:03:19,800 --> 00:03:21,609 When we search for evidence of life 68 00:03:21,633 --> 00:03:23,409 in the ice ages in North America, 69 00:03:23,433 --> 00:03:25,576 we find things like the bones of mammoths 70 00:03:25,600 --> 00:03:27,742 {\an1}or maybe even hearth stones or spear points 71 00:03:27,766 --> 00:03:29,442 from the people that used to live here, 72 00:03:29,466 --> 00:03:32,109 {\an1}and very rarely we find the remains of those humans. 73 00:03:32,133 --> 00:03:34,376 But the story is still so incomplete, 74 00:03:34,400 --> 00:03:37,076 there's so much more information we need to find. 75 00:03:37,100 --> 00:03:39,242 ♪ ♪ 76 00:03:39,266 --> 00:03:41,509 JOHNSON: That's why the discovery of footprints 77 00:03:41,533 --> 00:03:44,500 {\an1}here at White Sands is so significant. 78 00:03:46,366 --> 00:03:49,076 {\an1}Could they help answer some of the greatest mysteries 79 00:03:49,100 --> 00:03:52,642 of the Ice Age? 80 00:03:52,666 --> 00:03:57,242 {\an8}♪ ♪ 81 00:03:57,266 --> 00:03:59,842 {\an8}The precise location of this site 82 00:03:59,866 --> 00:04:01,542 {\an8}is a secret. 83 00:04:01,566 --> 00:04:03,342 These dunes cover 84 00:04:03,366 --> 00:04:07,176 {\an1}nearly 300 square miles... 85 00:04:07,200 --> 00:04:11,476 {\an1}with some rising over 50 feet. 86 00:04:11,500 --> 00:04:13,942 I'm driving through these snow-white dunes. 87 00:04:13,966 --> 00:04:15,509 It's kind of a surreal landscape. 88 00:04:15,533 --> 00:04:16,809 Once we get through the dunes, 89 00:04:16,833 --> 00:04:18,742 we'll be out in the great ancient lakebed, 90 00:04:18,766 --> 00:04:21,500 and it's absolutely covered with tracks. 91 00:04:23,666 --> 00:04:26,709 (voiceover): I'm Kirk Johnson. 92 00:04:26,733 --> 00:04:27,876 As a paleontologist, 93 00:04:27,900 --> 00:04:29,509 {\an1}I've spent most of my career 94 00:04:29,533 --> 00:04:31,976 studying the remains of ancient life. 95 00:04:32,000 --> 00:04:34,409 {\an1}But footprints can tell 96 00:04:34,433 --> 00:04:38,409 {\an1}really detailed stories about the past. 97 00:04:38,433 --> 00:04:42,133 ♪ ♪ 98 00:04:45,900 --> 00:04:46,877 30 minutes later, 99 00:04:46,901 --> 00:04:49,833 {\an1}we've reached our destination: 100 00:04:52,400 --> 00:04:56,776 {\an1}a huge dried-up lakebed. 101 00:04:56,800 --> 00:04:59,776 As the wind scours this remote area, 102 00:04:59,800 --> 00:05:05,209 {\an1}new prints are being revealed, and old ones disappear. 103 00:05:05,233 --> 00:05:07,876 {\an8}It seems like such an improbable place 104 00:05:07,900 --> 00:05:09,576 {\an8}to even look for tracks. 105 00:05:09,600 --> 00:05:12,742 {\an8}(voiceover): Joining me is David Bustos. 106 00:05:12,766 --> 00:05:15,109 {\an8}He's leading the team of scientists 107 00:05:15,133 --> 00:05:17,776 {\an1}investigating the footprints. 108 00:05:17,800 --> 00:05:20,009 BUSTOS: You look out and it's just bleak desert, 109 00:05:20,033 --> 00:05:22,942 {\an1}and who would think that there's all these trackways here? 110 00:05:22,966 --> 00:05:26,709 JOHNSON (voiceover): As my eyes adjust to the brightness, 111 00:05:26,733 --> 00:05:28,976 round patterns start to appear. 112 00:05:29,000 --> 00:05:30,242 {\an7}So there's one there... Yes. 113 00:05:30,266 --> 00:05:31,309 {\an8}And there and there, 114 00:05:31,333 --> 00:05:32,342 {\an7}and there and there, there... 115 00:05:32,366 --> 00:05:35,242 {\an8}BUSTOS: Yeah. 116 00:05:35,266 --> 00:05:36,709 {\an7}Oh, yeah. Those are amazing. 117 00:05:36,733 --> 00:05:37,776 {\an8}Uh-huh. 118 00:05:37,800 --> 00:05:40,676 {\an8}♪ ♪ 119 00:05:40,700 --> 00:05:44,609 {\an8}(voiceover): The mysterious shapes are over five feet apart, 120 00:05:44,633 --> 00:05:47,676 {\an7}and nearly two feet across. 121 00:05:47,700 --> 00:05:51,842 {\an7}These are the fossilized tracks of an Ice Age giant... 122 00:05:51,866 --> 00:05:54,509 {\an8}a Columbian mammoth. 123 00:05:54,533 --> 00:05:58,276 {\an8}It died more than 10,000 years ago, 124 00:05:58,300 --> 00:05:59,942 {\an7}but its footprints remain. 125 00:05:59,966 --> 00:06:01,809 {\an8}♪ ♪ 126 00:06:01,833 --> 00:06:03,400 {\an8}(mammoth trumpeting) 127 00:06:05,633 --> 00:06:08,542 {\an8}The tracks are preserved in various ways. 128 00:06:08,566 --> 00:06:12,576 {\an1}Sometimes the wind fills them with different textured sand, 129 00:06:12,600 --> 00:06:15,709 {\an1}leaving ghostly impressions, 130 00:06:15,733 --> 00:06:20,309 {\an7}while others dry into hard casts which are exposed 131 00:06:20,333 --> 00:06:24,542 {\an7}when the softer ground around them erodes away. 132 00:06:24,566 --> 00:06:26,742 {\an7}One of the things that really stand out at White Sands 133 00:06:26,766 --> 00:06:28,542 {\an7}is just thousands and thousands of footprints preserved. 134 00:06:28,566 --> 00:06:31,009 In this area, we'll see trackways 135 00:06:31,033 --> 00:06:33,142 {\an1}that go for ten miles in one direction 136 00:06:33,166 --> 00:06:34,642 and two or three miles in another direction. 137 00:06:34,666 --> 00:06:35,942 You know, there might be 138 00:06:35,966 --> 00:06:37,842 over 100,000 prints throughout this large area. 139 00:06:37,866 --> 00:06:40,376 {\an3}Do... it's okay to walk on them? 140 00:06:40,400 --> 00:06:41,776 We can walk near them and around them, 141 00:06:41,800 --> 00:06:44,009 as long as we don't disturb the surface below 142 00:06:44,033 --> 00:06:45,366 {\an1}or add more sediment in. 143 00:06:47,366 --> 00:06:49,042 {\an8}JOHNSON (voiceover): We need to be careful not to 144 00:06:49,066 --> 00:06:52,576 {\an7}step on the fragile prints... 145 00:06:52,600 --> 00:06:55,209 {\an1}and the team tries to only visit the trackway areas 146 00:06:55,233 --> 00:06:56,576 {\an1}when the ground is dry, 147 00:06:56,600 --> 00:06:58,566 and hard enough to support their weight. 148 00:07:00,800 --> 00:07:04,009 {\an1}The surface is always changing. 149 00:07:04,033 --> 00:07:05,976 {\an1}We are seeing more erosion. 150 00:07:06,000 --> 00:07:10,033 {\an1}Every year, more and more prints are becoming visible. 151 00:07:12,200 --> 00:07:15,042 JOHNSON (voiceover): And along with the many mammoth prints here, 152 00:07:15,066 --> 00:07:18,042 {\an1}we soon spot traces of another large creature. 153 00:07:18,066 --> 00:07:19,342 BUSTOS: They're very common, 154 00:07:19,366 --> 00:07:21,042 {\an8}they'll sort of look like an S shape... 155 00:07:21,066 --> 00:07:22,826 {\an8}Yep. You'll see them connecting to each other. 156 00:07:28,066 --> 00:07:29,242 {\an7}There's one here, right? 157 00:07:29,266 --> 00:07:31,609 {\an8}Yep. There's another one coming through... 158 00:07:31,633 --> 00:07:33,366 {\an8}I think as well, right there. 159 00:07:35,300 --> 00:07:37,809 {\an8}JOHNSON (voiceover): Twice the size of a human foot, 160 00:07:37,833 --> 00:07:41,042 {\an1}and with giant, curved claws, 161 00:07:41,066 --> 00:07:44,842 {\an1}these are the prints of a massive ground sloth, 162 00:07:44,866 --> 00:07:48,776 {\an1}a beast more than double the weight of a grizzly bear, 163 00:07:48,800 --> 00:07:51,976 {\an1}that walked this land thousands of years ago. 164 00:07:52,000 --> 00:07:53,742 (sloth panting) 165 00:07:53,766 --> 00:07:55,876 {\an1}So that's sort of how the story of White Sands began. 166 00:07:55,900 --> 00:07:58,209 People, they've seen these incredible footprints, 167 00:07:58,233 --> 00:07:59,542 and they thought that it was Bigfoot. 168 00:07:59,566 --> 00:08:01,542 (chuckling): Bigfoot with three weird claws. 169 00:08:01,566 --> 00:08:03,642 Yes. 170 00:08:03,666 --> 00:08:06,142 {\an8}JOHNSON (voiceover): Then we discover something even more special. 171 00:08:06,166 --> 00:08:07,809 {\an8}That is a human footprint. 172 00:08:07,833 --> 00:08:09,742 {\an7}Yeah, so there's... there's a human footprint right there. 173 00:08:09,766 --> 00:08:10,876 {\an8}(laughing): Wow. 174 00:08:10,900 --> 00:08:12,009 {\an8}Yeah, so if you look... 175 00:08:12,033 --> 00:08:13,142 {\an8}That is amazing. 176 00:08:13,166 --> 00:08:15,109 {\an8}Here's the heel. 177 00:08:15,133 --> 00:08:16,742 {\an8}Okay. Right here. 178 00:08:16,766 --> 00:08:18,942 JOHNSON (voiceover): Scattered across the landscape 179 00:08:18,966 --> 00:08:20,709 {\an1}are human footprints 180 00:08:20,733 --> 00:08:23,742 {\an7}from thousands of years ago. 181 00:08:23,766 --> 00:08:27,309 {\an8}Each track is the trace of an ancient person, 182 00:08:27,333 --> 00:08:32,609 {\an1}the shape of their bare feet locked in the sediment. 183 00:08:32,633 --> 00:08:35,309 Look at this, this is amazing here. 184 00:08:35,333 --> 00:08:38,176 {\an8}This actually looks like a human print right in there. 185 00:08:38,200 --> 00:08:39,976 ♪ ♪ 186 00:08:40,000 --> 00:08:43,076 JOHNSON (voiceover): Could these extraordinary human footprints 187 00:08:43,100 --> 00:08:46,709 {\an1}help answer two big questions: 188 00:08:46,733 --> 00:08:50,476 {\an1}when did people first set foot in North America? 189 00:08:50,500 --> 00:08:52,576 {\an1}And did their arrival contribute to 190 00:08:52,600 --> 00:08:56,466 the disappearance of giant Ice Age animals? 191 00:08:59,200 --> 00:09:01,442 20,000 years ago, 192 00:09:01,466 --> 00:09:05,142 Earth was in the grip of an ice age. 193 00:09:05,166 --> 00:09:07,142 {\an1}The climate was colder, 194 00:09:07,166 --> 00:09:10,233 {\an1}vast ice sheets covered much of North America... 195 00:09:12,233 --> 00:09:14,842 and White Sands was not a desert, 196 00:09:14,866 --> 00:09:17,876 {\an1}but a huge lake... Lake Otero. 197 00:09:17,900 --> 00:09:19,542 ♪ ♪ 198 00:09:19,566 --> 00:09:22,876 {\an1}The lakeshore surrounding it teemed with life. 199 00:09:22,900 --> 00:09:26,576 Giant ground sloths wielding big claws 200 00:09:26,600 --> 00:09:29,042 {\an1}shared this wetland with mammoths 201 00:09:29,066 --> 00:09:31,342 {\an1}weighing up to ten tons. 202 00:09:31,366 --> 00:09:32,542 Alongside them, 203 00:09:32,566 --> 00:09:36,842 packs of dire wolves hunting for a kill, 204 00:09:36,866 --> 00:09:40,509 and hardy North American camels. 205 00:09:40,533 --> 00:09:43,876 {\an1}These Ice Age giants disappeared from the fossil record 206 00:09:43,900 --> 00:09:47,276 {\an1}over 10,000 years ago. 207 00:09:47,300 --> 00:09:53,309 {\an1}So the human footprints here are probably at least that old. 208 00:09:53,333 --> 00:09:56,842 ♪ ♪ 209 00:09:56,866 --> 00:09:59,100 {\an1}But they could be much older. 210 00:10:01,166 --> 00:10:03,876 What can they reveal about the deep history 211 00:10:03,900 --> 00:10:06,542 {\an1}of humans on this continent, 212 00:10:06,566 --> 00:10:10,833 {\an1}and how they met the challenges of life in the Ice Age? 213 00:10:14,100 --> 00:10:16,309 ♪ ♪ 214 00:10:16,333 --> 00:10:17,542 To find out, 215 00:10:17,566 --> 00:10:20,476 {\an8}David has assembled a team of scientists 216 00:10:20,500 --> 00:10:22,733 {\an1}to uncover the tracks' hidden secrets. 217 00:10:24,000 --> 00:10:25,509 {\an8}BENNETT: I'm confident in it now, 218 00:10:25,533 --> 00:10:27,276 {\an7}that that's mammoth, and it links to your one in the, 219 00:10:27,300 --> 00:10:30,009 um, that you've got in cross section there. 220 00:10:30,033 --> 00:10:31,533 {\an5}Cross section over there? Okay. Yeah. 221 00:10:33,433 --> 00:10:35,109 JOHNSON: One of them is Matthew Bennett, 222 00:10:35,133 --> 00:10:38,609 {\an1}a forensic footprint expert from England. 223 00:10:38,633 --> 00:10:41,642 ♪ ♪ 224 00:10:41,666 --> 00:10:44,409 {\an7}On the eastern side of the ancient lake, 225 00:10:44,433 --> 00:10:46,109 {\an8}close to the restricted area of 226 00:10:46,133 --> 00:10:48,676 {\an7}the White Sands Missile Range, 227 00:10:48,700 --> 00:10:52,409 {\an7}Matthew is excavating a remarkable set 228 00:10:52,433 --> 00:10:54,842 of human footprints. 229 00:10:54,866 --> 00:10:55,909 {\an1}JOHNSON: Hey, Matthew, 230 00:10:55,933 --> 00:10:56,910 {\an7}how's it going? 231 00:10:56,934 --> 00:10:58,209 {\an8}It's going well. 232 00:10:58,233 --> 00:11:00,709 {\an8}These are amazing. They are. 233 00:11:00,733 --> 00:11:03,509 {\an8}Are these... so, are these 234 00:11:03,533 --> 00:11:05,609 {\an7}just the ones you've exposed this afternoon, then? 235 00:11:05,633 --> 00:11:07,442 {\an8}Yep, there's a double trail. 236 00:11:07,466 --> 00:11:12,242 {\an7}Um, somebody going this way, and somebody going that way. 237 00:11:12,266 --> 00:11:14,442 {\an7}How far do they go off in that direction? 238 00:11:14,466 --> 00:11:15,576 {\an8}So, in that direction, 239 00:11:15,600 --> 00:11:17,276 {\an8}about three-quarters of a mile, 240 00:11:17,300 --> 00:11:19,742 {\an8}something like that, and then they go to 241 00:11:19,766 --> 00:11:21,609 {\an8}the boundary fence on the missile range 242 00:11:21,633 --> 00:11:24,509 {\an8}and an unknown distance into the missile range. 243 00:11:24,533 --> 00:11:26,842 ♪ ♪ 244 00:11:26,866 --> 00:11:29,909 JOHNSON: How common is it to have a track this long? 245 00:11:29,933 --> 00:11:31,209 BENNETT: Okay, so I've looked at tracks 246 00:11:31,233 --> 00:11:34,042 all around the world, and this, to my knowledge, 247 00:11:34,066 --> 00:11:37,276 {\an1}is the longest human trackway anywhere in the world. 248 00:11:37,300 --> 00:11:39,509 JOHNSON: Oh, that's amazing. 249 00:11:39,533 --> 00:11:41,576 {\an1}Could it be the same person going away and coming back? 250 00:11:41,600 --> 00:11:43,609 {\an8}Absolutely. They're the same size. 251 00:11:43,633 --> 00:11:44,709 {\an8}It's actually quite a small individual. 252 00:11:44,733 --> 00:11:46,709 {\an8}It could be a woman, 253 00:11:46,733 --> 00:11:50,309 {\an8}but could be a male adolescent equally. 254 00:11:50,333 --> 00:11:51,509 The size is... 255 00:11:51,533 --> 00:11:53,309 {\an4}Looks like a size five or something. Yeah. 256 00:11:53,333 --> 00:11:55,142 But the tracks are very big. 257 00:11:55,166 --> 00:11:57,676 {\an8}There's sort of 30% of the track, 258 00:11:57,700 --> 00:11:59,933 {\an7}maybe more is pure slippage. 259 00:12:02,200 --> 00:12:04,509 {\an8}It's very wet and slippery conditions 260 00:12:04,533 --> 00:12:06,976 {\an8}as the individual has been moving. 261 00:12:07,000 --> 00:12:12,809 JOHNSON (voiceover): Some are clearly defined imprints, 262 00:12:12,833 --> 00:12:16,442 but many are stretched out and distorted, 263 00:12:16,466 --> 00:12:19,809 {\an8}an indication that the walker was moving fast, 264 00:12:19,833 --> 00:12:22,133 {\an8}and slipping on wet, muddy ground. 265 00:12:23,866 --> 00:12:26,342 Some prints are bent out of shape, 266 00:12:26,366 --> 00:12:29,842 {\an1}from a foot sliding sideways, 267 00:12:29,866 --> 00:12:31,076 which could mean 268 00:12:31,100 --> 00:12:33,933 {\an1}the person was carrying something on their journey. 269 00:12:35,033 --> 00:12:38,542 BENNETT: They were also carrying a child. 270 00:12:38,566 --> 00:12:40,342 {\an1}Oh, they're carrying a child as well? 271 00:12:40,366 --> 00:12:41,642 They're carrying a child. 272 00:12:41,666 --> 00:12:42,942 {\an1}How do you know that they're carrying a child? 273 00:12:42,966 --> 00:12:46,342 BENNETT: Along the trackway, there are very small, 274 00:12:46,366 --> 00:12:48,076 {\an1}tiny little children's prints. 275 00:12:48,100 --> 00:12:52,209 They sort of face the direction of travel. 276 00:12:52,233 --> 00:12:54,142 So if you imagine you were carrying a child on your hip 277 00:12:54,166 --> 00:12:56,209 and you wanted to readjust, you... 278 00:12:56,233 --> 00:12:57,742 you put it down... Right. 279 00:12:57,766 --> 00:12:58,909 {\an1}...and then you readjust, 280 00:12:58,933 --> 00:13:02,276 and there's a few small child prints, 281 00:13:02,300 --> 00:13:04,666 {\an1}pick the child up again and carry on. 282 00:13:06,566 --> 00:13:08,042 {\an8}Just over to here... 283 00:13:08,066 --> 00:13:10,242 {\an8}JOHNSON (voiceover): A little farther along the same trackway, 284 00:13:10,266 --> 00:13:14,609 Matthew discovers a twist in the story. 285 00:13:14,633 --> 00:13:17,442 {\an1}The travelers were not alone. 286 00:13:17,466 --> 00:13:19,876 What's this unusual set of tracks? 287 00:13:19,900 --> 00:13:23,976 {\an1}So there are a series of sloth tracks here 288 00:13:24,000 --> 00:13:26,009 {\an1}entering from, from... 289 00:13:26,033 --> 00:13:27,276 {\an1}to the left there... So this is the first one. 290 00:13:27,300 --> 00:13:29,542 {\an7}And then it comes out over here. 291 00:13:29,566 --> 00:13:30,842 That's really the amazing one, 292 00:13:30,866 --> 00:13:32,742 {\an1}you can see the claws of the sloth so clearly. 293 00:13:32,766 --> 00:13:33,776 {\an1}BENNETT: You can, yeah. 294 00:13:33,800 --> 00:13:35,776 {\an1}It's a beautiful, a beautiful track. 295 00:13:35,800 --> 00:13:37,176 {\an7}They're not large tracks. Yeah. 296 00:13:37,200 --> 00:13:40,276 {\an1}So it's a relatively small sloth. 297 00:13:40,300 --> 00:13:43,700 {\an1}Bear-size, I would have suggested. 298 00:13:45,366 --> 00:13:47,342 JOHNSON (voiceover): Was this sloth here 299 00:13:47,366 --> 00:13:50,076 at the same time as the humans? 300 00:13:50,100 --> 00:13:52,642 {\an1}The sloth's footprints are right on top of 301 00:13:52,666 --> 00:13:55,009 {\an1}the outbound human track. 302 00:13:55,033 --> 00:13:57,342 {\an1}Which means this animal must have arrived 303 00:13:57,366 --> 00:14:02,776 after the travelers first passed by. 304 00:14:02,800 --> 00:14:05,976 {\an1}Where do they actually step on the human track? 305 00:14:06,000 --> 00:14:07,342 {\an1}So... Is it this one? 306 00:14:07,366 --> 00:14:09,176 {\an1}It's actually just over there. 307 00:14:09,200 --> 00:14:10,809 {\an1}There's an example where they, 308 00:14:10,833 --> 00:14:13,033 {\an1}they cut across the human track. 309 00:14:18,300 --> 00:14:21,276 {\an1}But the sloth did something quite cool. 310 00:14:21,300 --> 00:14:25,109 {\an7}It seems to have gone from all fours up onto its hind legs. 311 00:14:25,133 --> 00:14:28,742 {\an7}It's done a little dance around... 312 00:14:28,766 --> 00:14:31,233 {\an7}And then it goes off that way. 313 00:14:34,266 --> 00:14:36,942 {\an7}So it crawls in kind of like sloth-like, 314 00:14:36,966 --> 00:14:38,542 {\an8}and then as it gets here, 315 00:14:38,566 --> 00:14:39,776 {\an7}it kind of pivots around and up 316 00:14:39,800 --> 00:14:40,842 {\an8}and looks, looks... 317 00:14:40,866 --> 00:14:42,542 {\an7}Looks, scents the air, and off. 318 00:14:42,566 --> 00:14:43,576 {\an8}...and pivots 319 00:14:43,600 --> 00:14:44,576 {\an7}and then heads off that way. 320 00:14:44,600 --> 00:14:45,543 {\an7}That's correct. 321 00:14:45,567 --> 00:14:46,976 {\an8}A little sloth dance. 322 00:14:47,000 --> 00:14:48,280 {\an7}Yeah, that's exactly what it is. 323 00:14:50,566 --> 00:14:52,609 {\an8}JOHNSON (voiceover): Matthew thinks the sloth 324 00:14:52,633 --> 00:14:56,509 {\an7}noticed the human tracks and reacted. 325 00:14:56,533 --> 00:14:59,742 {\an7}Either the sloth's either visually responding to the track 326 00:14:59,766 --> 00:15:02,342 {\an7}or it smells something. 327 00:15:02,366 --> 00:15:04,342 {\an1}My instinct is smell. 328 00:15:04,366 --> 00:15:07,309 {\an1}It basically reared up to scent the air a little bit more 329 00:15:07,333 --> 00:15:11,342 {\an1}and then decided to, to disappear off. 330 00:15:11,366 --> 00:15:14,442 {\an1}They're not here at the same time, 331 00:15:14,466 --> 00:15:17,442 {\an1}but within a few minutes, hours of each other, 332 00:15:17,466 --> 00:15:18,742 {\an1}they're here. 333 00:15:18,766 --> 00:15:21,276 {\an8}(chuckling): That's a phenomenal thing. 334 00:15:21,300 --> 00:15:24,709 {\an8}Some small person having a stroll 335 00:15:24,733 --> 00:15:27,200 {\an8}on a landscape full of giant ground sloths. 336 00:15:29,300 --> 00:15:31,942 (voiceover): The tracks at White Sands show 337 00:15:31,966 --> 00:15:36,776 {\an1}just how close humans here came to Ice Age animals. 338 00:15:36,800 --> 00:15:39,009 Imagine what it must have been like 339 00:15:39,033 --> 00:15:41,942 to meet one of these enormous beasts in the flesh. 340 00:15:41,966 --> 00:15:44,100 (sloth groaning) 341 00:15:46,566 --> 00:15:49,109 ♪ ♪ 342 00:15:49,133 --> 00:15:51,409 {\an1}You can get a sense of these Ice Age encounters 343 00:15:51,433 --> 00:15:55,109 at La Brea Tar Pits in Los Angeles. 344 00:15:55,133 --> 00:15:59,976 {\an1}Here, animals that wandered into tar deposits were trapped, 345 00:16:00,000 --> 00:16:01,766 {\an1}and their bones were preserved. 346 00:16:03,733 --> 00:16:06,709 In the last century, experts have unearthed 347 00:16:06,733 --> 00:16:10,342 {\an1}more than a million fossils here. 348 00:16:10,366 --> 00:16:11,310 {\an1}EMILY LINDSEY: Hey. 349 00:16:11,334 --> 00:16:12,442 Hey Emily, how are you doing? 350 00:16:12,466 --> 00:16:13,409 {\an1}Good, how are you? 351 00:16:13,433 --> 00:16:14,410 {\an1}Nice to see you again. Good to see you. 352 00:16:14,434 --> 00:16:15,709 {\an1}Welcome to the Tar Pits. Thanks. 353 00:16:15,733 --> 00:16:17,609 Oh, here's our sloth, huh? Yeah. 354 00:16:17,633 --> 00:16:20,609 This thing is amazing, so massive. 355 00:16:20,633 --> 00:16:22,709 {\an1}It's majestic. 356 00:16:22,733 --> 00:16:25,642 JOHNSON (voiceover): Curator Emily Lindsey works with fossils of the giant beasts 357 00:16:25,666 --> 00:16:30,209 {\an1}that lived in North America during the last Ice Age. 358 00:16:30,233 --> 00:16:32,076 {\an1}So how much do you think this guy weighed? 359 00:16:32,100 --> 00:16:33,609 Probably more than a ton. 360 00:16:33,633 --> 00:16:35,009 {\an1}And when people talk about sloths, 361 00:16:35,033 --> 00:16:37,042 {\an1}they talk about how they move so slowly, 362 00:16:37,066 --> 00:16:38,909 {\an7}would this guy have moved slowly? 363 00:16:38,933 --> 00:16:40,342 {\an8}You know, it wouldn't have been like, 364 00:16:40,366 --> 00:16:41,909 {\an8}a runner... Yeah. 365 00:16:41,933 --> 00:16:45,642 {\an7}...but it wouldn't have been so slow as the modern sloths 366 00:16:45,666 --> 00:16:48,742 {\an1}that are really only adapted for living in trees. 367 00:16:48,766 --> 00:16:51,342 What would an animal like this eat? 368 00:16:51,366 --> 00:16:53,676 So they were mostly herbivores, 369 00:16:53,700 --> 00:16:55,276 {\an1}and it looks like they were eating a lot of 370 00:16:55,300 --> 00:16:56,409 {\an1}kind of desert shrubs 371 00:16:56,433 --> 00:16:59,133 that would have been prevalent in the area. 372 00:17:00,866 --> 00:17:02,876 {\an1}Sloths are part of this very strange group of animals 373 00:17:02,900 --> 00:17:05,742 called Xenarthrans, and it includes the sloths, 374 00:17:05,766 --> 00:17:07,642 the armadillos, 375 00:17:07,666 --> 00:17:09,909 and the anteaters. 376 00:17:09,933 --> 00:17:11,076 And like armadillos, some species 377 00:17:11,100 --> 00:17:14,276 produced bony armor, only in this case, 378 00:17:14,300 --> 00:17:15,609 {\an1}it's in the form of these 379 00:17:15,633 --> 00:17:17,809 small sort of pebble-like bones 380 00:17:17,833 --> 00:17:21,076 that were embedded inside its skin. 381 00:17:21,100 --> 00:17:22,309 {\an1}Oh, that's why I love sloths so much. 382 00:17:22,333 --> 00:17:23,342 {\an1}(laughing): They're so cool, 383 00:17:23,366 --> 00:17:24,509 {\an1}they're such amazing animals. 384 00:17:24,533 --> 00:17:26,609 {\an1}Yeah, they're one of the weirdest animals, 385 00:17:26,633 --> 00:17:28,776 {\an1}and it's a piece of ecology 386 00:17:28,800 --> 00:17:31,842 that has just completely gone from earth. 387 00:17:31,866 --> 00:17:33,609 (indistinct chatter) 388 00:17:33,633 --> 00:17:35,576 JOHNSON (voiceover): Nearby, I've spotted another 389 00:17:35,600 --> 00:17:39,642 {\an1}lost species whose tracks we see at White Sands. 390 00:17:39,666 --> 00:17:42,142 This is an amazing beast, isn't it? 391 00:17:42,166 --> 00:17:44,342 Yeah, the Columbian mammoth. 392 00:17:44,366 --> 00:17:45,876 JOHNSON (voiceover): From fossil evidence, 393 00:17:45,900 --> 00:17:48,076 {\an1}we know that mammoths arrived in North America 394 00:17:48,100 --> 00:17:52,576 {\an1}around 1.8 million years ago. 395 00:17:52,600 --> 00:17:55,609 {\an1}When you stand beneath the skeletons of these huge animals, 396 00:17:55,633 --> 00:17:59,042 {\an1}you can't help but wonder, 397 00:17:59,066 --> 00:18:03,333 {\an1}why did they go extinct less than 13,000 years ago? 398 00:18:05,133 --> 00:18:08,676 Was it because of a change in climate? 399 00:18:08,700 --> 00:18:10,976 Or human influence? 400 00:18:11,000 --> 00:18:14,842 {\an1}Or a combination of the two? 401 00:18:14,866 --> 00:18:16,842 LINDSEY: It seems to have been a really rapid event. 402 00:18:16,866 --> 00:18:18,509 As we we're coming out of the Ice Age, 403 00:18:18,533 --> 00:18:20,176 {\an1}we're going through all these big climate upheavals, 404 00:18:20,200 --> 00:18:22,876 {\an1}so we need to know how much overlap 405 00:18:22,900 --> 00:18:26,776 there actually was between when humans arrived 406 00:18:26,800 --> 00:18:29,642 and when the last animals disappeared 407 00:18:29,666 --> 00:18:32,576 {\an1}in order to know what role humans might have played 408 00:18:32,600 --> 00:18:34,409 in that extinction. 409 00:18:34,433 --> 00:18:39,566 {\an8}♪ ♪ 410 00:18:41,500 --> 00:18:43,309 {\an8}JOHNSON (voiceover): The footprints at White Sands 411 00:18:43,333 --> 00:18:46,966 {\an7}might be the oldest human prints ever found in North America. 412 00:18:49,666 --> 00:18:53,609 {\an7}They could shed new light on the lives of Indigenous peoples 413 00:18:53,633 --> 00:18:56,309 {\an7}and their long history on this continent. 414 00:18:56,333 --> 00:18:59,176 {\an1}It's, it's just so amazing to see these tracks... 415 00:18:59,200 --> 00:19:00,309 There's another one crossing there. 416 00:19:00,333 --> 00:19:01,509 Yeah. 417 00:19:01,533 --> 00:19:04,176 {\an8}JOHNSON (voiceover): Today, I'm visiting 418 00:19:04,200 --> 00:19:07,442 {\an8}the U.S. Army's White Sands missile range, 419 00:19:07,466 --> 00:19:09,766 {\an7}just across the boundary from the national park. 420 00:19:11,933 --> 00:19:13,942 Here there are more animal prints, 421 00:19:13,966 --> 00:19:15,742 {\an1}including those of a mammoth, 422 00:19:15,766 --> 00:19:20,709 {\an1}and this magnificent trackway of a ground sloth, 423 00:19:20,733 --> 00:19:23,700 {\an1}crossed by the footprints of an ancient camel. 424 00:19:26,700 --> 00:19:30,576 {\an1}Can you imagine this whole area 425 00:19:30,600 --> 00:19:32,576 {\an1}with all these animals here? 426 00:19:32,600 --> 00:19:35,042 {\an4}Would have been amazing, huh? (sighing): Oh. 427 00:19:35,066 --> 00:19:36,942 {\an1}Mammoths, sloths, cats, dogs. Yeah. 428 00:19:36,966 --> 00:19:38,209 Right? Yes. 429 00:19:38,233 --> 00:19:39,842 {\an1}I always say we need to build a time machine. 430 00:19:39,866 --> 00:19:41,233 (laughter) 431 00:19:43,100 --> 00:19:45,009 JOHNSON (voiceover): Joining me are Joe Watkins, 432 00:19:45,033 --> 00:19:46,576 an archaeologist and member of 433 00:19:46,600 --> 00:19:49,109 {\an1}the Choctaw Nation of Oklahoma, 434 00:19:49,133 --> 00:19:54,076 {\an1}and Kim Charlie from the Pueblo of Acoma in New Mexico. 435 00:19:54,100 --> 00:19:57,642 They want to see the prints for themselves, 436 00:19:57,666 --> 00:19:58,976 and learn more about 437 00:19:59,000 --> 00:20:04,076 {\an1}the people who once walked across this landscape. 438 00:20:04,100 --> 00:20:06,809 {\an8}We have this tie where us Native Americans 439 00:20:06,833 --> 00:20:09,009 {\an8}have been here for a very long time. 440 00:20:09,033 --> 00:20:13,242 {\an1}And I believe that, you know, I really believe that. 441 00:20:13,266 --> 00:20:15,376 {\an1}And that ties back into, you know, 442 00:20:15,400 --> 00:20:17,209 {\an1}our migration stories where 443 00:20:17,233 --> 00:20:20,909 {\an1}we evolved somewhere, but we don't 444 00:20:20,933 --> 00:20:22,809 {\an1}specifically know where. 445 00:20:22,833 --> 00:20:23,810 {\an1}These are stories that 446 00:20:23,834 --> 00:20:27,176 {\an1}we believe in our hearts as tribes, 447 00:20:27,200 --> 00:20:32,409 {\an1}pueblos, you know, that we take, that we hold sacred to us. 448 00:20:32,433 --> 00:20:34,842 {\an1}So when we come back to these areas 449 00:20:34,866 --> 00:20:37,542 and we find evidence of footprints 450 00:20:37,566 --> 00:20:41,376 of our thousands of great ancestors, 451 00:20:41,400 --> 00:20:44,642 {\an1}you know, we just kind of, like, it's amazing. 452 00:20:44,666 --> 00:20:46,042 {\an1}So we did exist here. 453 00:20:46,066 --> 00:20:48,809 {\an7}The tribes talk about going way back. 454 00:20:48,833 --> 00:20:51,609 {\an8}We all talk about having been here forever. 455 00:20:51,633 --> 00:20:53,076 {\an7}We've never been anywhere else. 456 00:20:53,100 --> 00:20:56,009 {\an1}We have the evidence, it really does 457 00:20:56,033 --> 00:20:58,042 put our feet prints 458 00:20:58,066 --> 00:21:01,109 {\an1}firmly into the past here in North America. 459 00:21:01,133 --> 00:21:04,576 {\an1}These are our relatives. 460 00:21:04,600 --> 00:21:06,909 {\an1}We've been here since time immemorial 461 00:21:06,933 --> 00:21:08,800 and hopefully we'll continue on. 462 00:21:11,666 --> 00:21:12,842 JOHNSON (voiceover): When Europeans arrived 463 00:21:12,866 --> 00:21:15,642 on this continent, they began a pattern of 464 00:21:15,666 --> 00:21:17,342 {\an1}ignoring the rights and stories 465 00:21:17,366 --> 00:21:21,042 {\an1}of Indigenous peoples. 466 00:21:21,066 --> 00:21:27,042 {\an1}With the colonization in the 14, 1500s, 467 00:21:27,066 --> 00:21:29,776 {\an1}a lot of tribal histories have either been lost 468 00:21:29,800 --> 00:21:33,742 {\an1}or have been pushed back or have been tossed aside. 469 00:21:33,766 --> 00:21:36,342 {\an1}This was once our land, you know. 470 00:21:36,366 --> 00:21:39,076 {\an4}Mother Earth was our mother... Mm-hmm. 471 00:21:39,100 --> 00:21:41,109 {\an1}...and we're the descendants of her. 472 00:21:41,133 --> 00:21:44,576 And we're the people that try to take care of it, 473 00:21:44,600 --> 00:21:48,042 but you've got the Western people 474 00:21:48,066 --> 00:21:52,642 have come in and just taken over areas where, 475 00:21:52,666 --> 00:21:54,242 you know, they have no respect. 476 00:21:54,266 --> 00:21:56,209 {\an1}Please understand that 477 00:21:56,233 --> 00:21:58,876 {\an1}we Native Americans were here first. 478 00:21:58,900 --> 00:22:01,876 {\an1}It's kind of an awful thing 479 00:22:01,900 --> 00:22:05,642 where we've been put on little reservations. 480 00:22:05,666 --> 00:22:09,976 {\an1}You know, where we once had the freedom to roam. 481 00:22:10,000 --> 00:22:12,609 ♪ ♪ 482 00:22:12,633 --> 00:22:13,909 JOHNSON (voiceover): European-Americans not only 483 00:22:13,933 --> 00:22:17,276 took control of Indigenous territories, 484 00:22:17,300 --> 00:22:18,709 but some also spread 485 00:22:18,733 --> 00:22:21,033 {\an1}misleading narratives about Indigenous people. 486 00:22:21,866 --> 00:22:23,509 (indistinct chatter) 487 00:22:23,533 --> 00:22:24,842 ♪ ♪ 488 00:22:24,866 --> 00:22:26,409 WATKINS: There's pretty much always been a conflict 489 00:22:26,433 --> 00:22:29,009 {\an1}between archaeologists and American Indians. 490 00:22:29,033 --> 00:22:31,342 In many ways, 491 00:22:31,366 --> 00:22:34,142 {\an1}archaeologists have taken over. 492 00:22:34,166 --> 00:22:37,342 {\an1}They've sort of colonized American Indian history, 493 00:22:37,366 --> 00:22:41,209 {\an1}and they felt that they, they're the ones 494 00:22:41,233 --> 00:22:43,742 who tell the true story of the past. 495 00:22:43,766 --> 00:22:47,109 {\an1}So there's been that conflict between 496 00:22:47,133 --> 00:22:49,242 {\an1}whose story is the true history. 497 00:22:49,266 --> 00:22:51,109 Archaeologists also 498 00:22:51,133 --> 00:22:54,276 {\an1}came out to archaeological sites, 499 00:22:54,300 --> 00:22:55,509 {\an1}started excavating, 500 00:22:55,533 --> 00:22:58,942 took the materials, took them back to museums, 501 00:22:58,966 --> 00:23:00,976 and tribal people never saw them again. 502 00:23:01,000 --> 00:23:03,909 ♪ ♪ 503 00:23:03,933 --> 00:23:05,309 JOHNSON: Over the centuries, 504 00:23:05,333 --> 00:23:07,509 some white scholars used archaeology 505 00:23:07,533 --> 00:23:10,809 as a way to dismiss Indigenous people's accounts 506 00:23:10,833 --> 00:23:15,709 {\an1}and ancestral connections to the land. 507 00:23:15,733 --> 00:23:19,409 It really wasn't until 40 years ago 508 00:23:19,433 --> 00:23:22,576 {\an1}that Indians had a say in who was excavating 509 00:23:22,600 --> 00:23:25,542 {\an1}and what happened with the results of those excavations. 510 00:23:25,566 --> 00:23:29,676 ♪ ♪ 511 00:23:29,700 --> 00:23:30,942 JOHNSON: Here at White Sands, 512 00:23:30,966 --> 00:23:33,976 {\an1}the scientists are consulting with local tribes 513 00:23:34,000 --> 00:23:38,033 {\an1}and pueblos to study and record these important prints. 514 00:23:39,366 --> 00:23:44,476 {\an1}They hope to solve one of the biggest mysteries of all: 515 00:23:44,500 --> 00:23:48,900 {\an1}when did humans first arrive in North America? 516 00:23:53,166 --> 00:23:57,609 {\an1}Fossil records show that by at least 100,000 years ago, 517 00:23:57,633 --> 00:24:00,409 {\an1}modern humans... Homo sapiens... 518 00:24:00,433 --> 00:24:04,376 Began spreading from Africa across the planet. 519 00:24:04,400 --> 00:24:06,942 The Americas were surrounded by ocean 520 00:24:06,966 --> 00:24:09,209 and out of reach. 521 00:24:09,233 --> 00:24:13,776 {\an1}But during the last Ice Age, massive ice sheets formed 522 00:24:13,800 --> 00:24:17,442 and sea levels dropped by over 400 feet, 523 00:24:17,466 --> 00:24:22,042 exposing land between Siberia and Alaska. 524 00:24:22,066 --> 00:24:23,642 {\an1}Many scientists agree 525 00:24:23,666 --> 00:24:27,409 {\an1}that this is how humans got to North America. 526 00:24:27,433 --> 00:24:31,509 But when exactly did they first arrive? 527 00:24:31,533 --> 00:24:35,942 {\an1}Throughout the 20th century, many archaeologists 528 00:24:35,966 --> 00:24:39,676 {\an1}thought the answer lay in these stone projectile points 529 00:24:39,700 --> 00:24:42,166 found all across North America. 530 00:24:44,466 --> 00:24:46,876 {\an1}They were made by people from what became known as 531 00:24:46,900 --> 00:24:50,309 the Clovis culture. 532 00:24:50,333 --> 00:24:51,776 WATKINS: I have a replica 533 00:24:51,800 --> 00:24:55,076 {\an1}Clovis point with me. 534 00:24:55,100 --> 00:24:56,642 {\an1}They look about like this. 535 00:24:56,666 --> 00:24:58,209 Some are larger, some are smaller. 536 00:24:58,233 --> 00:25:01,109 {\an1}There's a very characteristic flake 537 00:25:01,133 --> 00:25:03,442 {\an1}that's taken out of the base 538 00:25:03,466 --> 00:25:05,066 {\an1}up to the middle of the point. 539 00:25:06,666 --> 00:25:08,442 JOHNSON: The oldest known Clovis points 540 00:25:08,466 --> 00:25:10,400 {\an1}are about 13,000 years old. 541 00:25:12,033 --> 00:25:14,876 And for a long time, many archaeologists 542 00:25:14,900 --> 00:25:16,609 thought that humans arrived in North America 543 00:25:16,633 --> 00:25:20,542 {\an1}no earlier than that. 544 00:25:20,566 --> 00:25:22,809 {\an1}So these Clovis points have been found 545 00:25:22,833 --> 00:25:24,409 {\an1}all across North America, 546 00:25:24,433 --> 00:25:27,876 {\an1}from the Atlantic coast on the east, 547 00:25:27,900 --> 00:25:30,242 {\an1}all the way out into the, the west coast. 548 00:25:30,266 --> 00:25:34,776 {\an1}So with this, such a broad geographical span of material, 549 00:25:34,800 --> 00:25:37,042 it's why most archaeologists thought 550 00:25:37,066 --> 00:25:40,342 that Clovis was the first archaeological culture 551 00:25:40,366 --> 00:25:41,409 in North America. 552 00:25:41,433 --> 00:25:44,242 JOHNSON (voiceover): More recently, 553 00:25:44,266 --> 00:25:47,142 {\an1}this view has been challenged by the excavation of 554 00:25:47,166 --> 00:25:50,009 older sites, with stone artifacts 555 00:25:50,033 --> 00:25:52,342 {\an1}that suggest humans lived in North America 556 00:25:52,366 --> 00:25:53,343 at least 2,000 years 557 00:25:53,367 --> 00:25:56,642 {\an1}before the Clovis culture. 558 00:25:56,666 --> 00:25:59,542 ♪ ♪ 559 00:25:59,566 --> 00:26:01,976 There are some archaeological sites... 560 00:26:02,000 --> 00:26:04,509 {\an1}one in Florida, one in Texas... 561 00:26:04,533 --> 00:26:10,209 {\an1}that date about 15,000, 15,200 years ago. 562 00:26:10,233 --> 00:26:13,442 {\an1}So those are currently the oldest dates we have 563 00:26:13,466 --> 00:26:16,242 {\an1}for the early peopling of the New World. 564 00:26:16,266 --> 00:26:19,609 {\an8}♪ ♪ 565 00:26:19,633 --> 00:26:22,009 {\an8}JOHNSON: But now the discoveries at White Sands 566 00:26:22,033 --> 00:26:25,309 {\an8}may support even earlier dates, 567 00:26:25,333 --> 00:26:28,842 {\an7}and could shed new light on 568 00:26:28,866 --> 00:26:32,733 {\an8}how people came to North America. 569 00:26:35,233 --> 00:26:39,909 {\an7}About 20,000 years ago was the peak of the last Ice Age, 570 00:26:39,933 --> 00:26:42,809 {\an7}the Last Glacial Maximum. 571 00:26:42,833 --> 00:26:47,842 {\an7}Gigantic ice sheets blocked the route into North America. 572 00:26:47,866 --> 00:26:51,876 {\an1}But there's geological evidence that as the climate warmed, 573 00:26:51,900 --> 00:26:56,309 {\an1}an ice-free corridor opened up. 574 00:26:56,333 --> 00:26:59,366 {\an1}Was this how humans reached the rest of the continent? 575 00:27:01,766 --> 00:27:04,909 {\an1}So one thing about the ice-free corridor, 576 00:27:04,933 --> 00:27:06,676 {\an1}it didn't really open up 577 00:27:06,700 --> 00:27:10,109 {\an1}until 13, 14,000 years ago. 578 00:27:10,133 --> 00:27:11,642 {\an1}So if it wasn't open, 579 00:27:11,666 --> 00:27:15,442 {\an1}it wasn't likely that anyone could have come that way 580 00:27:15,466 --> 00:27:17,700 {\an1}and come in to North America. 581 00:27:19,433 --> 00:27:25,009 JOHNSON: If the tracks at White Sands pre-date the ice-free corridor, 582 00:27:25,033 --> 00:27:26,576 {\an1}they will add more weight 583 00:27:26,600 --> 00:27:29,676 {\an1}to the idea that humans arrived here earlier 584 00:27:29,700 --> 00:27:34,433 {\an1}than many archaeologists previously thought. 585 00:27:35,433 --> 00:27:37,609 ♪ ♪ 586 00:27:37,633 --> 00:27:40,442 Searching for clues, 587 00:27:40,466 --> 00:27:43,842 {\an1}David Bustos is studying some other remarkable human prints. 588 00:27:43,866 --> 00:27:45,309 {\an7}I don't know if you can see right here, 589 00:27:45,333 --> 00:27:46,909 {\an8}this might be more of a child. 590 00:27:46,933 --> 00:27:51,742 {\an7}It's about, maybe, four, four inches or so across. 591 00:27:51,766 --> 00:27:53,776 {\an1}And it's right next to an adult print. 592 00:27:53,800 --> 00:27:55,209 {\an1}You don't normally think of, you know, 593 00:27:55,233 --> 00:27:58,342 {\an1}taking your child all the way across the country or so, 594 00:27:58,366 --> 00:28:00,309 unless you're, um, if you're hunting, 595 00:28:00,333 --> 00:28:01,542 {\an1}you might leave the child back at home, 596 00:28:01,566 --> 00:28:02,942 {\an1}but we see the children everywhere, 597 00:28:02,966 --> 00:28:05,809 {\an1}so they're part of the scene or part of the landscape. 598 00:28:05,833 --> 00:28:07,342 ♪ ♪ 599 00:28:07,366 --> 00:28:11,176 JOHNSON: The footprints tell stories of Ice Age life. 600 00:28:11,200 --> 00:28:13,576 {\an1}But how long ago were these people here? 601 00:28:13,600 --> 00:28:15,709 ♪ ♪ 602 00:28:15,733 --> 00:28:17,476 {\an1}In order to date the prints, 603 00:28:17,500 --> 00:28:19,733 {\an1}the team has dug a trench. 604 00:28:22,033 --> 00:28:23,842 (rocks rumbling) 605 00:28:23,866 --> 00:28:25,842 {\an1}It reveals layers of sediment, 606 00:28:25,866 --> 00:28:28,076 {\an1}deposited over many years, 607 00:28:28,100 --> 00:28:31,066 {\an1}along the shore of this ancient lake. 608 00:28:32,866 --> 00:28:36,809 {\an1}Stamped on these buried surfaces are human prints, 609 00:28:36,833 --> 00:28:40,733 {\an1}and the further down they are, the older they are. 610 00:28:41,500 --> 00:28:44,809 {\an7}But just how old are they? 611 00:28:44,833 --> 00:28:46,309 {\an1}I can put them both on. 612 00:28:46,333 --> 00:28:47,976 {\an8}Okay, sure. 613 00:28:48,000 --> 00:28:50,909 JOHNSON: To help find the answer, David has been joined 614 00:28:50,933 --> 00:28:55,209 {\an1}by geologists Kathleen Springer and Jeff Pigati, 615 00:28:55,233 --> 00:28:57,842 {\an1}who is also an expert in radiocarbon dating. 616 00:28:57,866 --> 00:29:01,476 ♪ ♪ 617 00:29:01,500 --> 00:29:03,276 {\an7}You've cut a cross section... What are you trying to see 618 00:29:03,300 --> 00:29:05,442 {\an8}with the cross section? SPRINGER: So the footprints themselves 619 00:29:05,466 --> 00:29:06,942 {\an1}are just an impression on a surface, 620 00:29:06,966 --> 00:29:08,309 {\an1}there's nothing to date. 621 00:29:08,333 --> 00:29:10,876 {\an1}It's an inorganic thing, you have to find something organic 622 00:29:10,900 --> 00:29:14,676 {\an7}that you can date above and below the footprints, 623 00:29:14,700 --> 00:29:16,009 {\an1}and get good dates on them, 624 00:29:16,033 --> 00:29:17,176 {\an1}so that you can actually say, 625 00:29:17,200 --> 00:29:20,576 {\an1}"That footprint is between these two ages." 626 00:29:20,600 --> 00:29:24,942 {\an8}JOHNSON (voiceover): In this trench, Kathleen and Jeff have made a crucial find. 627 00:29:24,966 --> 00:29:27,976 ♪ ♪ 628 00:29:28,000 --> 00:29:32,209 {\an1}Sandwiched in the layers above and below the footprints 629 00:29:32,233 --> 00:29:35,576 are scatterings of ancient seeds, 630 00:29:35,600 --> 00:29:39,409 {\an1}precious organic material which the team can date. 631 00:29:39,433 --> 00:29:42,076 {\an1}That way they can establish a window of time, 632 00:29:42,100 --> 00:29:45,100 {\an1}for when the prints were made. 633 00:29:46,866 --> 00:29:49,709 There were actually plants growing on this, 634 00:29:49,733 --> 00:29:51,809 {\an1}on the surface when, you know, 635 00:29:51,833 --> 00:29:53,342 {\an1}these critters were walking around. 636 00:29:53,366 --> 00:29:55,242 {\an1}So the same layers that have the tracks will have the seeds. 637 00:29:55,266 --> 00:29:56,576 {\an4}Absolutely, above and below them. Yeah. 638 00:29:56,600 --> 00:29:57,776 {\an1}Yes, so above and below them, 639 00:29:57,800 --> 00:30:00,642 {\an1}that way we can constrain in time. 640 00:30:00,666 --> 00:30:04,342 {\an1}So your seeds are effectively little timepieces, right? 641 00:30:04,366 --> 00:30:06,076 They're like little clocks or something buried in the... 642 00:30:06,100 --> 00:30:08,276 {\an7}They're little capsules, yeah. 643 00:30:08,300 --> 00:30:09,776 {\an7}And basically the, the... 644 00:30:09,800 --> 00:30:13,609 {\an7}these things are really resistant to, to decay. 645 00:30:13,633 --> 00:30:16,242 {\an1}And so they look like they were put down on the, 646 00:30:16,266 --> 00:30:18,409 {\an1}on the landscape just yesterday, but, in fact, 647 00:30:18,433 --> 00:30:20,442 {\an1}they might be tens and, you know, 648 00:30:20,466 --> 00:30:22,133 {\an1}tens of thousands of years old. 649 00:30:23,700 --> 00:30:26,076 {\an8}JOHNSON (voiceover): Jeff will take the seeds back to his lab in Denver, 650 00:30:26,100 --> 00:30:28,876 {\an7}and use radiocarbon dating to find out how old they are. 651 00:30:28,900 --> 00:30:31,442 {\an8}♪ ♪ 652 00:30:31,466 --> 00:30:34,076 JOHNSON: When I talk to you in six months' time, 653 00:30:34,100 --> 00:30:35,342 either you have what you expect, 654 00:30:35,366 --> 00:30:38,242 {\an4}PIGATI: Mm-hm. which is around 12,000 years, 655 00:30:38,266 --> 00:30:40,776 or you have humans here earlier than you expect, 656 00:30:40,800 --> 00:30:43,242 or mammoths are here later than you expect. 657 00:30:43,266 --> 00:30:44,709 {\an1}PIGATI: Something's going to be pretty cool either way, right? 658 00:30:44,733 --> 00:30:46,209 {\an1}So it seems like you're going to get 659 00:30:46,233 --> 00:30:48,709 {\an1}a really interesting result no matter what the result is here. 660 00:30:48,733 --> 00:30:51,042 {\an4}PIGATI: It is a win-win, no question about it. Yeah. 661 00:30:51,066 --> 00:30:52,409 That's a rare thing in paleontology. 662 00:30:52,433 --> 00:30:53,742 {\an1}PIGATI: It's kind of nice. Yeah. 663 00:30:53,766 --> 00:30:55,076 JOHNSON: Dying to hear what you find out. 664 00:30:55,100 --> 00:30:56,900 Yeah. Yeah, us too, us too. 665 00:30:58,733 --> 00:31:02,742 JOHNSON (voiceover): The trackways at White Sands are constantly changing... 666 00:31:02,766 --> 00:31:06,676 {\an1}as the wind erodes away the surface to reveal new prints, 667 00:31:06,700 --> 00:31:10,633 {\an1}it's also turning existing ones to dust. 668 00:31:11,966 --> 00:31:13,509 BUSTOS: It's great because we can see the prints, 669 00:31:13,533 --> 00:31:15,776 but then they are rapidly blowing away. 670 00:31:15,800 --> 00:31:18,609 {\an1}So we want to capture the data before it's gone. 671 00:31:18,633 --> 00:31:20,942 {\an1}Some of these really soft ones like this, 672 00:31:20,966 --> 00:31:24,676 {\an1}once they're exposed, in a few months they'll be gone. 673 00:31:24,700 --> 00:31:26,909 {\an1}Some type of, you know, priceless data is, is being... 674 00:31:26,933 --> 00:31:28,842 {\an1}is right here, is being lost. 675 00:31:28,866 --> 00:31:30,876 {\an8}It's the surface, we're losing the surface, 676 00:31:30,900 --> 00:31:32,409 and these are where all the prints are. 677 00:31:32,433 --> 00:31:37,742 ♪ ♪ 678 00:31:37,766 --> 00:31:42,542 JOHNSON: To record this precious evidence before the wind blows it away, 679 00:31:42,566 --> 00:31:45,900 {\an1}the team is mapping the site using aerial imagery. 680 00:31:48,000 --> 00:31:51,109 BUSTOS: One of the main reasons is to fly over the area 681 00:31:51,133 --> 00:31:52,142 {\an1}and then get an elevation model 682 00:31:52,166 --> 00:31:54,442 so we can see where these prints are. 683 00:31:54,466 --> 00:31:56,776 And then we're gonna re-fly it again, 684 00:31:56,800 --> 00:31:59,109 {\an1}and so with that we'll be able to look at 685 00:31:59,133 --> 00:32:01,442 {\an1}from this year to next year 686 00:32:01,466 --> 00:32:02,809 {\an1}we'll see how much erosion's happening, 687 00:32:02,833 --> 00:32:03,876 {\an1}so we can see how fast 688 00:32:03,900 --> 00:32:06,166 {\an1}the prints are moving and going away. 689 00:32:08,966 --> 00:32:14,342 JOHNSON: One question they hope to answer using digital imaging 690 00:32:14,366 --> 00:32:17,433 {\an1}is whether the people here were hunting the giant animals. 691 00:32:19,800 --> 00:32:24,909 {\an1}David shows me an intriguing set of tracks that may hold clues. 692 00:32:24,933 --> 00:32:26,909 Dave, what kind of image is this? 693 00:32:26,933 --> 00:32:28,509 {\an1}BUSTOS: It's a photogrammetry. 694 00:32:28,533 --> 00:32:30,642 {\an1}You know, so basically overlapping photos. 695 00:32:30,666 --> 00:32:32,042 {\an1}I think in this image, 696 00:32:32,066 --> 00:32:33,876 {\an1}there might have been 400 or 500 different images 697 00:32:33,900 --> 00:32:37,009 {\an1}and they're all stitched together. 698 00:32:37,033 --> 00:32:39,476 You can, you know, tip the images upside down, 699 00:32:39,500 --> 00:32:41,333 {\an1}see it in different directions. 700 00:32:42,233 --> 00:32:44,242 {\an1}So this image right here 701 00:32:44,266 --> 00:32:46,142 is actually a giant ground sloth. 702 00:32:46,166 --> 00:32:47,609 It's walking along. 703 00:32:47,633 --> 00:32:51,276 {\an1}These are hind and fore feet, so when they weave in and out, 704 00:32:51,300 --> 00:32:52,277 {\an1}what you see is a hind foot, 705 00:32:52,301 --> 00:32:53,309 {\an1}and then the forefoot comes in front 706 00:32:53,333 --> 00:32:54,909 {\an1}with the very long claw. 707 00:32:54,933 --> 00:32:56,809 {\an1}And then right here, it changes. 708 00:32:56,833 --> 00:32:58,666 {\an1}So it stands up, actually. 709 00:33:00,133 --> 00:33:03,009 JOHNSON (voiceover): What caused this sudden change in behavior? 710 00:33:03,033 --> 00:33:05,309 David has a theory. 711 00:33:05,333 --> 00:33:08,742 BUSTOS: If you look close, you'll see a set of human tracks, 712 00:33:08,766 --> 00:33:11,676 {\an1}And what's really exciting, we took measurements. 713 00:33:11,700 --> 00:33:13,776 {\an1}You can see they're running toward the sloth. 714 00:33:13,800 --> 00:33:15,242 {\an1}If you're in the field, 715 00:33:15,266 --> 00:33:16,742 {\an1}you'd actually see where they're almost toe to toe, you know, 716 00:33:16,766 --> 00:33:18,609 {\an1}almost chest to chest, it looks like. 717 00:33:18,633 --> 00:33:20,209 {\an7}I don't know if they're throwing a spear 718 00:33:20,233 --> 00:33:22,576 {\an7}or what they're doing, but they come right up to each other. 719 00:33:22,600 --> 00:33:24,242 {\an1}The sloth's spinning around and making, like, 720 00:33:24,266 --> 00:33:25,709 {\an1}it looks like a sweeping motion. 721 00:33:25,733 --> 00:33:27,933 {\an7}Actually, there's claw marks on the ground. 722 00:33:29,500 --> 00:33:31,709 There's another set of human prints 723 00:33:31,733 --> 00:33:34,833 {\an1}sort of running up along this direction. 724 00:33:36,466 --> 00:33:37,842 JOHNSON (voiceover): David believes these trackways 725 00:33:37,866 --> 00:33:41,833 {\an1}are evidence that humans were actually hunting sloths. 726 00:33:44,466 --> 00:33:45,776 (sloth grunts) 727 00:33:45,800 --> 00:33:49,176 {\an1}But what was it like to take on such big animals? 728 00:33:49,200 --> 00:33:50,709 (sloth growls) 729 00:33:50,733 --> 00:33:53,476 {\an1}La Brea Museum curator Emily Lindsey 730 00:33:53,500 --> 00:33:56,033 has investigated how humans hunted them. 731 00:33:57,200 --> 00:34:00,242 {\an8}So these are our collections 732 00:34:00,266 --> 00:34:02,709 {\an7}where we keep all of the fossils that have been excavated 733 00:34:02,733 --> 00:34:04,609 {\an7}over the last hundred years. 734 00:34:04,633 --> 00:34:05,976 {\an1}There's millions of fossils here. 735 00:34:06,000 --> 00:34:08,642 Yeah, there are literally millions of fossils here. 736 00:34:08,666 --> 00:34:11,009 {\an8}And here are some of our sloth claws. 737 00:34:11,033 --> 00:34:12,342 {\an8}JOHNSON: Oh man, look at those things, 738 00:34:12,366 --> 00:34:14,609 {\an7}these are serious claws. 739 00:34:14,633 --> 00:34:17,009 What did they use the claws for? 740 00:34:17,033 --> 00:34:20,042 {\an8}Some paleontologists think they might have used them 741 00:34:20,066 --> 00:34:21,942 to dig roots out of the ground. 742 00:34:21,966 --> 00:34:23,009 They've found burrows 743 00:34:23,033 --> 00:34:25,642 {\an8}that they think these guys dug there, 744 00:34:25,666 --> 00:34:28,776 {\an8}where there's actually scratch marks on the wall 745 00:34:28,800 --> 00:34:30,209 {\an1}that line up with the the hands of giant sloths. 746 00:34:30,233 --> 00:34:31,542 But, of course, 747 00:34:31,566 --> 00:34:34,542 {\an1}they would have been really useful for defense, as well. 748 00:34:34,566 --> 00:34:36,809 JOHNSON (voiceover): But despite their fearsome appearance, 749 00:34:36,833 --> 00:34:40,109 {\an1}archaeological evidence shows that ground sloths 750 00:34:40,133 --> 00:34:42,142 {\an1}might have been on the menu 751 00:34:42,166 --> 00:34:44,133 for hungry humans. 752 00:34:45,600 --> 00:34:46,942 LINDSEY: You know, we have a couple of sites 753 00:34:46,966 --> 00:34:49,809 {\an1}that have been found where it looks pretty clear 754 00:34:49,833 --> 00:34:52,176 that humans were, if not hunting, 755 00:34:52,200 --> 00:34:54,300 at least butchering giant ground sloths. 756 00:34:55,366 --> 00:34:57,776 We've got stone tools 757 00:34:57,800 --> 00:34:59,142 and we've got cut marks on the bones. 758 00:34:59,166 --> 00:35:02,476 Although we have many more sites 759 00:35:02,500 --> 00:35:04,142 {\an1}that show humans hunting 760 00:35:04,166 --> 00:35:06,976 {\an1}and eating things like mammoths and horses and camels 761 00:35:07,000 --> 00:35:08,876 {\an1}than we do of giant sloths. 762 00:35:08,900 --> 00:35:11,676 {\an1}So, they may have been a food source of last resort. 763 00:35:11,700 --> 00:35:13,442 {\an1}Maybe bison tastes better, or... 764 00:35:13,466 --> 00:35:16,209 Yeah, given the types of plants 765 00:35:16,233 --> 00:35:18,442 that we find in the sloth dung. 766 00:35:18,466 --> 00:35:19,642 {\an1}You know, desert plants 767 00:35:19,666 --> 00:35:21,842 {\an1}that tend to have a lot of chemicals in them. 768 00:35:21,866 --> 00:35:23,209 They might not have tasted very good. 769 00:35:23,233 --> 00:35:24,576 {\an1}Huh, interesting. 770 00:35:24,600 --> 00:35:26,576 {\an1}So what kind of techniques were humans using 771 00:35:26,600 --> 00:35:28,342 {\an1}to hunt and kill these animals? 772 00:35:28,366 --> 00:35:30,309 LINDSEY: They had spears, but, of course, 773 00:35:30,333 --> 00:35:31,742 {\an1}the most important tool that humans had 774 00:35:31,766 --> 00:35:34,476 {\an1}were their big brains and their social groups 775 00:35:34,500 --> 00:35:37,109 {\an1}and ability to communicate. Hm. 776 00:35:37,133 --> 00:35:38,309 ♪ ♪ 777 00:35:38,333 --> 00:35:40,576 JOHNSON (voiceover): Teamwork and planning, 778 00:35:40,600 --> 00:35:45,176 {\an1}these were the keys to bringing down huge Ice Age beasts. 779 00:35:45,200 --> 00:35:46,976 ♪ ♪ 780 00:35:47,000 --> 00:35:50,409 {\an1}But once the animal was dead, 781 00:35:50,433 --> 00:35:52,942 {\an8}what did people do with all that meat? 782 00:35:52,966 --> 00:35:55,409 {\an8}♪ ♪ 783 00:35:55,433 --> 00:35:57,109 {\an7}One of the challenges you have, if you're, 784 00:35:57,133 --> 00:35:58,542 {\an8}if you're living in this environment, 785 00:35:58,566 --> 00:36:01,342 {\an7}or hunting in this environment, is how do you get your meat 786 00:36:01,366 --> 00:36:03,576 {\an7}from where you kill the animal to where you camp? 787 00:36:03,600 --> 00:36:06,842 ♪ ♪ 788 00:36:06,866 --> 00:36:09,242 JOHNSON: Dan Odess is an expert 789 00:36:09,266 --> 00:36:12,042 {\an7}in prehistoric archaeology. 790 00:36:12,066 --> 00:36:15,909 {\an7}He searches for evidence to show how humans might have dealt 791 00:36:15,933 --> 00:36:18,442 {\an1}with the animals they killed. 792 00:36:18,466 --> 00:36:21,376 {\an1}And alongside the footprints, 793 00:36:21,400 --> 00:36:24,742 he shows me a very different kind of track. 794 00:36:24,766 --> 00:36:27,176 DAN ODESS: We have these, these really interesting 795 00:36:27,200 --> 00:36:29,742 linear structures. 796 00:36:29,766 --> 00:36:31,442 There are four of them. 797 00:36:31,466 --> 00:36:34,909 You can see here one, two, three, four. 798 00:36:34,933 --> 00:36:39,442 JOHNSON: What could have caused these strange marks in the sand? 799 00:36:39,466 --> 00:36:40,776 ODESS: We were kind of wondering 800 00:36:40,800 --> 00:36:43,809 {\an1}initially, could this be a product of animal behavior 801 00:36:43,833 --> 00:36:45,442 {\an1}rather than human behavior? 802 00:36:45,466 --> 00:36:46,742 But, interestingly, 803 00:36:46,766 --> 00:36:48,176 {\an1}one of the things we see 804 00:36:48,200 --> 00:36:49,742 {\an1}and you can see it very clearly in this one, 805 00:36:49,766 --> 00:36:53,409 {\an7}we've got people walking along behind it. 806 00:36:53,433 --> 00:36:56,809 {\an8}JOHNSON: Dan believes this is important archaeological evidence 807 00:36:56,833 --> 00:36:59,142 {\an7}of human engineering. 808 00:36:59,166 --> 00:37:01,109 They're, they're drag lines. 809 00:37:01,133 --> 00:37:03,442 So impressions left in the mud 810 00:37:03,466 --> 00:37:05,109 {\an1}as somebody probably pulled 811 00:37:05,133 --> 00:37:06,876 a pole or poles. Okay. 812 00:37:06,900 --> 00:37:10,909 With presumably meat or something else on them. 813 00:37:10,933 --> 00:37:12,376 {\an1}JOHNSON: And that's a typical way to move meat around? 814 00:37:12,400 --> 00:37:13,542 I think this is the first time 815 00:37:13,566 --> 00:37:16,366 {\an1}it's been described for the Ice Age. 816 00:37:18,733 --> 00:37:20,176 JOHNSON (voiceover): The team thinks these tracks 817 00:37:20,200 --> 00:37:23,076 {\an1}could be the earliest known evidence of an ancient device 818 00:37:23,100 --> 00:37:28,833 {\an1}used to carry heavy loads, such as large amounts of meat. 819 00:37:30,133 --> 00:37:32,376 ODESS: Instead of dragging the carcass back to the camp, 820 00:37:32,400 --> 00:37:35,742 {\an1}they would strap it onto a couple of poles, 821 00:37:35,766 --> 00:37:37,409 {\an1}and not one, or two poles. 822 00:37:37,433 --> 00:37:39,142 {\an1}At this point, we're not sure whether 823 00:37:39,166 --> 00:37:40,642 {\an1}they're dragging a single pole 824 00:37:40,666 --> 00:37:44,176 {\an1}or whether they're using two poles hitched together. 825 00:37:44,200 --> 00:37:47,309 {\an1}JOHNSON (off-camera): Huh, so like a primitive wheelbarrow, basically, right? 826 00:37:47,333 --> 00:37:48,976 {\an1}ODESS: So far we, we don't have any reason to think 827 00:37:49,000 --> 00:37:51,009 {\an1}they had a wheel. Right. 828 00:37:51,033 --> 00:37:52,176 Well, wheelbarrow with no wheel, how about that? 829 00:37:52,200 --> 00:37:53,742 Yeah, right, right. (chuckles) 830 00:37:53,766 --> 00:37:54,909 A barrow! Right, there you go. 831 00:37:54,933 --> 00:37:56,076 {\an5}Let's just call it a barrow. A barrow. 832 00:37:56,100 --> 00:37:57,976 ♪ ♪ 833 00:37:58,000 --> 00:38:01,533 JOHNSON (voiceover): But what could the device have looked like? 834 00:38:03,300 --> 00:38:05,542 {\an7}(birds flapping wings, squawking) 835 00:38:05,566 --> 00:38:10,209 {\an7}60 miles from the trackways is Elephant Butte Lake. 836 00:38:10,233 --> 00:38:12,109 {\an7}Experts think White Sands 837 00:38:12,133 --> 00:38:15,942 {\an7}had a similar environment during parts of the Ice Age. 838 00:38:15,966 --> 00:38:18,509 {\an1}Archaeologist Joe Watkins 839 00:38:18,533 --> 00:38:21,433 {\an1}has come here to conduct an experiment. 840 00:38:24,066 --> 00:38:26,176 {\an7}Joining him are fellow archaeologists Carol Ellick, 841 00:38:26,200 --> 00:38:29,076 CAROL ELLICK: I'll start with the lashing on this corner, 842 00:38:29,100 --> 00:38:30,676 all right? Yup. 843 00:38:30,700 --> 00:38:35,742 JOHNSON: And Edward Jolie, of Lakota and Muscogee descent, 844 00:38:35,766 --> 00:38:39,642 and a citizen of the Muscogee Nation of Oklahoma. 845 00:38:39,666 --> 00:38:41,909 EDWARD JOLIE: Is this going to be sufficiently stout, 846 00:38:41,933 --> 00:38:43,876 or should we cut a thicker one? 847 00:38:43,900 --> 00:38:45,709 ELLICK: I think that's pretty tiny, Ed. 848 00:38:45,733 --> 00:38:47,476 JOLIE: It is. 849 00:38:47,500 --> 00:38:50,676 {\an8}JOHNSON: The team wants to carry out experiments 850 00:38:50,700 --> 00:38:53,576 {\an7}to try to reproduce the tracks at White Sands. 851 00:38:53,600 --> 00:38:55,942 ♪ ♪ 852 00:38:55,966 --> 00:38:59,109 {\an1}They're building two simple structures 853 00:38:59,133 --> 00:39:01,176 {\an7}to see if one of them might leave 854 00:39:01,200 --> 00:39:05,709 {\an7}similar drag marks to those found in the desert. 855 00:39:05,733 --> 00:39:06,942 {\an7}Ed, if you want to 856 00:39:06,966 --> 00:39:10,033 {\an4}lash the end pieces together. JOLIE: Okay. 857 00:39:11,533 --> 00:39:13,676 I'll grab the important piece. 858 00:39:13,700 --> 00:39:16,942 JOHNSON: The first design is an A-frame structure, 859 00:39:16,966 --> 00:39:20,109 {\an1}based on a traditional device used by Indigenous peoples 860 00:39:20,133 --> 00:39:22,942 called a travois. 861 00:39:22,966 --> 00:39:25,142 They're attaching 40-pound weights 862 00:39:25,166 --> 00:39:27,542 {\an1}to represent a hunk of meat. 863 00:39:27,566 --> 00:39:29,009 I think that's the 40 pounds. 864 00:39:29,033 --> 00:39:31,342 {\an1}This feels, like, more than 40 pounds, is this...? 865 00:39:31,366 --> 00:39:33,909 {\an1}Honestly, that's 40 pounds. 866 00:39:33,933 --> 00:39:37,442 {\an1}Two 15-pound weights, plus two 5-pound weights. 867 00:39:37,466 --> 00:39:40,209 (chuckling) 868 00:39:40,233 --> 00:39:41,542 That's... 869 00:39:41,566 --> 00:39:43,476 We might have some structural issues. 870 00:39:43,500 --> 00:39:45,376 (laughter) I don't remember my daughter 871 00:39:45,400 --> 00:39:47,500 ever weighing this much! (laughs) 872 00:39:48,833 --> 00:39:51,342 {\an8}JOHNSON: Carol is going to pull each design. 873 00:39:51,366 --> 00:39:53,009 {\an8}Walking barefoot, like the people 874 00:39:53,033 --> 00:39:56,242 {\an7}who created the prints at White Sands. 875 00:39:56,266 --> 00:39:57,542 {\an8}It feels pretty stable. 876 00:39:57,566 --> 00:39:58,809 {\an7}ELLICK: It looks pretty stable. It feels, 877 00:39:58,833 --> 00:40:00,566 {\an8}from my end, it feels pretty good too. 878 00:40:02,833 --> 00:40:04,376 {\an8}ELLICK: I was going to follow the edge of the water, 879 00:40:04,400 --> 00:40:06,042 {\an8}is that what you were thinking? 880 00:40:06,066 --> 00:40:07,010 {\an8}WATKINS: I think that's a good way. 881 00:40:07,034 --> 00:40:08,842 {\an8}Okay. Okay. 882 00:40:08,866 --> 00:40:12,109 {\an7}(grunts) Whoa, getting started. 883 00:40:12,133 --> 00:40:14,209 {\an8}JOHNSON: Carol leaves behind clear footprints 884 00:40:14,233 --> 00:40:16,233 {\an7}and drag marks in the mud. 885 00:40:17,500 --> 00:40:20,942 {\an8}♪ ♪ 886 00:40:20,966 --> 00:40:23,409 {\an7}WATKINS: Look at that. JOLIE: Yeah, that's great. 887 00:40:23,433 --> 00:40:27,142 WATKINS: The footprints are both on one side. 888 00:40:27,166 --> 00:40:28,776 I would have thought there would have been footprints 889 00:40:28,800 --> 00:40:31,976 on either side and that the drag line, 890 00:40:32,000 --> 00:40:34,742 {\an5}would have been between the two. JOLIE: Mm-hm. 891 00:40:34,766 --> 00:40:37,376 {\an1}And it appears to me, as well, that what we're seeing 892 00:40:37,400 --> 00:40:40,142 {\an7}is that the footprints are the side opposite 893 00:40:40,166 --> 00:40:41,642 {\an7}the weight imbalance on the travois. 894 00:40:41,666 --> 00:40:45,242 {\an8}WATKINS: Either that or the fact that there are two sticks 895 00:40:45,266 --> 00:40:48,576 {\an8}is having an impact on the way it's moving. 896 00:40:48,600 --> 00:40:50,166 {\an7}JOLIE: Looks great. 897 00:40:52,233 --> 00:40:55,842 {\an8}JOHNSON: They record the marks for further study. 898 00:40:55,866 --> 00:40:57,609 {\an8}WATKINS: Let's get one up by that footprint 899 00:40:57,633 --> 00:41:01,733 {\an8}where the mud has pushed over to, okay? 900 00:41:03,166 --> 00:41:05,209 That's a good start. 901 00:41:05,233 --> 00:41:06,676 ♪ ♪ 902 00:41:06,700 --> 00:41:09,842 JOHNSON: Next, they try the second design... 903 00:41:09,866 --> 00:41:12,809 {\an1}a single pole with the same weight attached. 904 00:41:12,833 --> 00:41:14,109 WATKINS: Do you want me to come up a little bit? 905 00:41:14,133 --> 00:41:15,733 {\an1}ELLICK: Pull it forward a little bit. 906 00:41:18,033 --> 00:41:19,442 {\an8}So... Put that end down. 907 00:41:19,466 --> 00:41:21,576 {\an7}JOLIE: Come up parallel to this one. 908 00:41:21,600 --> 00:41:23,909 {\an7}ELLICK: All right, all right. 909 00:41:23,933 --> 00:41:27,442 {\an8}(stick dragging) 910 00:41:27,466 --> 00:41:30,933 {\an8}♪ ♪ 911 00:41:33,800 --> 00:41:39,609 JOHNSON: This creates a single drag line with a regular wobble pattern. 912 00:41:39,633 --> 00:41:41,809 {\an8}That feels quite different pulling it 913 00:41:41,833 --> 00:41:45,242 {\an8}on the single pole rather than the double travois. 914 00:41:45,266 --> 00:41:48,309 WATKINS: So it definitely is wobbling back and forth 915 00:41:48,333 --> 00:41:51,942 {\an1}much more than the one with the two-pole travois. 916 00:41:51,966 --> 00:41:53,576 {\an7}Standing and staring at them both in parallel, 917 00:41:53,600 --> 00:41:55,176 {\an7}it's really drawn into stark relief 918 00:41:55,200 --> 00:41:56,976 {\an9}Yeah. How different they are. 919 00:41:57,000 --> 00:41:59,342 {\an7}It's a bit of a surprise, actually. (shutter clicks) 920 00:41:59,366 --> 00:42:01,809 ♪ ♪ 921 00:42:01,833 --> 00:42:04,809 JOHNSON: But which design makes a pattern closest 922 00:42:04,833 --> 00:42:08,009 to the tracks found at White Sands? 923 00:42:08,033 --> 00:42:11,109 {\an8}WATKINS: My impressions are that the straighter lines 924 00:42:11,133 --> 00:42:14,276 {\an8}at White Sands pretty much equate with 925 00:42:14,300 --> 00:42:17,709 {\an8}the straighter lines we're getting with the travois. 926 00:42:17,733 --> 00:42:20,476 {\an7}That's definitely not saying that's the only way 927 00:42:20,500 --> 00:42:22,242 {\an7}they could have had those straight lines. 928 00:42:22,266 --> 00:42:26,142 {\an8}But just based on this initial experiment, 929 00:42:26,166 --> 00:42:30,900 {\an1}I would be more inclined to go with the double pole. 930 00:42:32,066 --> 00:42:35,909 JOHNSON: This experiment suggests how Ice Age humans 931 00:42:35,933 --> 00:42:40,109 {\an1}might have transported meat or other heavy objects. 932 00:42:40,133 --> 00:42:42,976 But how long ago were they walking along 933 00:42:43,000 --> 00:42:45,900 {\an1}the ancient lakeside at White Sands? 934 00:42:47,666 --> 00:42:49,776 ♪ ♪ 935 00:42:49,800 --> 00:42:52,476 {\an1}It was time to visit Denver to catch up 936 00:42:52,500 --> 00:42:54,476 with Jeff Pigati and Kathleen Springer. 937 00:42:54,500 --> 00:42:57,009 PIGATI: Yeah, right at the top of the sequence there. 938 00:42:57,033 --> 00:42:59,242 So that one has a stem attached. 939 00:42:59,266 --> 00:43:00,276 {\an1}Still has a stem attached? 940 00:43:00,300 --> 00:43:01,409 {\an1}Yeah. That's awesome. 941 00:43:01,433 --> 00:43:02,876 We'll go through there. Yeah. 942 00:43:02,900 --> 00:43:05,609 JOHNSON: At the U.S. Geological Survey Lab, 943 00:43:05,633 --> 00:43:08,009 {\an1}Jeff has been analyzing the seeds they found 944 00:43:08,033 --> 00:43:10,109 {\an1}in the sediment layers at White Sands. 945 00:43:10,133 --> 00:43:11,576 ♪ ♪ 946 00:43:11,600 --> 00:43:13,109 He's been using radiocarbon dating 947 00:43:13,133 --> 00:43:17,576 {\an1}to calculate the age of the seeds, and from that, 948 00:43:17,600 --> 00:43:19,933 {\an1}the age of the footprints. 949 00:43:21,433 --> 00:43:23,042 {\an8}PIGATI: This is the carbon extraction 950 00:43:23,066 --> 00:43:24,742 {\an1}and graphitization system. 951 00:43:24,766 --> 00:43:26,709 {\an1}And, basically, what we do here is take a seed. 952 00:43:26,733 --> 00:43:29,676 {\an1}We combust it in oxygen. 953 00:43:29,700 --> 00:43:31,476 We turn the carbon that's in the seed 954 00:43:31,500 --> 00:43:33,676 into carbon dioxide. 955 00:43:33,700 --> 00:43:35,076 {\an1}We get rid of everything else that's in the seed... 956 00:43:35,100 --> 00:43:36,442 {\an1}water and other other contaminant gases 957 00:43:36,466 --> 00:43:37,443 that we don't want... 958 00:43:37,467 --> 00:43:40,209 {\an1}and we end up with pure CO2. 959 00:43:40,233 --> 00:43:42,742 ♪ ♪ 960 00:43:42,766 --> 00:43:44,942 {\an1}And we basically take that carbon dioxide, 961 00:43:44,966 --> 00:43:47,209 {\an1}convert it to graphite, 962 00:43:47,233 --> 00:43:51,642 {\an1}and that's what we actually send out to the AMS lab. 963 00:43:51,666 --> 00:43:53,709 {\an7}So you turn the seed into a gas and then back into a solid. 964 00:43:53,733 --> 00:43:55,542 {\an7}That's exactly right, we start with a solid, 965 00:43:55,566 --> 00:43:57,409 {\an7}we turn it into a gas, clean it up, 966 00:43:57,433 --> 00:44:00,109 {\an7}and then end up with a pure graphite pellet at the end. 967 00:44:00,133 --> 00:44:01,909 {\an1}In these little targets, right here. 968 00:44:01,933 --> 00:44:03,409 {\an4}That's a tiny little thing. Exactly. 969 00:44:03,433 --> 00:44:05,342 {\an1}It's about the size of a pencil lead, they're very small. 970 00:44:05,366 --> 00:44:06,542 {\an1}And they're sealed into this thing? 971 00:44:06,566 --> 00:44:07,776 {\an1}That's right, exactly. 972 00:44:07,800 --> 00:44:09,442 {\an4}I see this little closed chamber. Yeah. 973 00:44:09,466 --> 00:44:11,842 JOHNSON (voiceover): The precious graphite pellets 974 00:44:11,866 --> 00:44:16,676 {\an1}are then sent to a mass spectrometry lab to be analyzed. 975 00:44:16,700 --> 00:44:17,876 {\an1}So what happens at the mass spectrometry lab? 976 00:44:17,900 --> 00:44:19,576 {\an1}Yeah, so that's where they measure the ratios 977 00:44:19,600 --> 00:44:21,576 {\an5}of the various carbon isotopes. Uh-huh. 978 00:44:21,600 --> 00:44:23,509 {\an1}And those are the data that we get back, 979 00:44:23,533 --> 00:44:25,376 and we use those to calculate the age. 980 00:44:25,400 --> 00:44:27,109 {\an8}♪ ♪ 981 00:44:27,133 --> 00:44:30,642 {\an8}JOHNSON (voiceover): It's the moment of truth. 982 00:44:30,666 --> 00:44:32,276 {\an8}After more than a year and a half, 983 00:44:32,300 --> 00:44:34,809 {\an7}have Kathleen and Jeff managed to find out 984 00:44:34,833 --> 00:44:36,933 {\an7}the age of the footprints? 985 00:44:39,166 --> 00:44:43,609 {\an7}So tell me, what were the dates of those footprints? 986 00:44:43,633 --> 00:44:46,109 {\an8}We were able to document that humans 987 00:44:46,133 --> 00:44:47,876 {\an8}were in White Sands National Park 988 00:44:47,900 --> 00:44:50,109 {\an8}between 23,000 years ago, 989 00:44:50,133 --> 00:44:52,342 {\an7}and about 21,000 years ago, 990 00:44:52,366 --> 00:44:54,376 JOHNSON: 23,000 years ago? 991 00:44:54,400 --> 00:44:57,242 {\an1}That's way older than there's been good evidence 992 00:44:57,266 --> 00:44:58,576 for humans in North America. 993 00:44:58,600 --> 00:45:00,842 It's about 10,000 years older 994 00:45:00,866 --> 00:45:02,842 {\an1}than sort of the established, sort of, 995 00:45:02,866 --> 00:45:06,242 {\an1}thought of when humans arrived in the Americas. 996 00:45:06,266 --> 00:45:08,976 JOHNSON: And you got tracks at more than one layer, 997 00:45:09,000 --> 00:45:11,076 which means that wasn't just one group of people 998 00:45:11,100 --> 00:45:13,009 at one moment in time. No. 999 00:45:13,033 --> 00:45:16,142 That it was many groups of people over a lot of time. 1000 00:45:16,166 --> 00:45:17,876 SPRINGER: 2,000 years. 1001 00:45:17,900 --> 00:45:19,976 I mean, 2,000 years itself 1002 00:45:20,000 --> 00:45:21,942 is a long duration. It is. 1003 00:45:21,966 --> 00:45:23,342 But the fact that they were here 1004 00:45:23,366 --> 00:45:26,042 {\an1}23,000 thousand years ago... Yeah, crazy, huh? 1005 00:45:26,066 --> 00:45:27,342 JOHNSON: Blows my mind, I mean... 1006 00:45:27,366 --> 00:45:29,276 SPRINGER: It blew our mind! (laughs) 1007 00:45:29,300 --> 00:45:32,542 {\an1}That's like 10,000 years before Clovis. 1008 00:45:32,566 --> 00:45:34,109 {\an1}SPRINGER: Yes. 1009 00:45:34,133 --> 00:45:36,442 {\an1}that's like the entire length of human civilization 1010 00:45:36,466 --> 00:45:37,876 before Clovis. 1011 00:45:37,900 --> 00:45:39,309 {\an1}SPRINGER: Yeah, go figure. 1012 00:45:39,333 --> 00:45:41,342 {\an1}This is not a subtle result. 1013 00:45:41,366 --> 00:45:42,876 ♪ ♪ 1014 00:45:42,900 --> 00:45:45,276 (voiceover): If these dates are correct, 1015 00:45:45,300 --> 00:45:47,409 {\an1}that would make the White Sands footprints 1016 00:45:47,433 --> 00:45:49,909 {\an1}the earliest direct evidence of humans 1017 00:45:49,933 --> 00:45:52,976 {\an1}ever found in North America. 1018 00:45:53,000 --> 00:45:54,709 PIGATI: This is the Last Glacial Maximum. 1019 00:45:54,733 --> 00:45:57,276 {\an1}This is when the ice sheets were at their maximum, 1020 00:45:57,300 --> 00:45:58,842 {\an1}and it's been thought that those ice sheets 1021 00:45:58,866 --> 00:46:01,276 {\an1}blocked people from coming down into North America. 1022 00:46:01,300 --> 00:46:03,076 {\an1}And what we found was that the people 1023 00:46:03,100 --> 00:46:04,942 {\an1}were already here at that time. 1024 00:46:04,966 --> 00:46:06,042 JOHNSON: So you couldn't be blocked from getting here 1025 00:46:06,066 --> 00:46:07,409 if you're already here. 1026 00:46:07,433 --> 00:46:08,976 {\an5}SPRINGER: That's right. If you're already here. 1027 00:46:09,000 --> 00:46:09,910 JOHNSON: And if you've been here for a couple thousand years? 1028 00:46:09,934 --> 00:46:11,342 {\an5}SPRINGER: Right. Yeah. 1029 00:46:11,366 --> 00:46:13,406 JOHNSON: What did you think when you saw the results? 1030 00:46:14,133 --> 00:46:15,542 {\an1}Holy... 1031 00:46:15,566 --> 00:46:17,076 (laughter) 1032 00:46:17,100 --> 00:46:18,376 {\an1}It was pretty much like that. I mean... 1033 00:46:18,400 --> 00:46:20,476 There was words that were spoken 1034 00:46:20,500 --> 00:46:22,742 that were emphatic words. Wow. Just wow, yeah. 1035 00:46:22,766 --> 00:46:26,976 ♪ ♪ 1036 00:46:27,000 --> 00:46:30,509 JOHNSON (voiceover): But some experts question these results. 1037 00:46:30,533 --> 00:46:31,742 {\an1}They're troubled by the lack 1038 00:46:31,766 --> 00:46:33,709 of additional archaeological evidence 1039 00:46:33,733 --> 00:46:35,433 {\an1}of this ancient population. 1040 00:46:37,333 --> 00:46:41,142 {\an1}Others say the dating method could be flawed 1041 00:46:41,166 --> 00:46:44,276 {\an1}arguing that the sediment layers may have been disturbed. 1042 00:46:44,300 --> 00:46:47,409 {\an1}Or the seeds may have absorbed older carbon 1043 00:46:47,433 --> 00:46:49,242 {\an1}from surrounding groundwater, 1044 00:46:49,266 --> 00:46:51,766 which could skew the carbon dating. 1045 00:46:53,700 --> 00:46:55,809 {\an1}This is an extraordinary discovery. 1046 00:46:55,833 --> 00:46:57,142 {\an1}How confident are you 1047 00:46:57,166 --> 00:47:00,276 {\an1}in the quality of the dates that you've achieved? 1048 00:47:00,300 --> 00:47:02,676 {\an1}We're very confident... These, these ages, 1049 00:47:02,700 --> 00:47:04,676 {\an1}we were able to reproduce them extremely well. 1050 00:47:04,700 --> 00:47:07,742 {\an1}They maintain what we call stratigraphic order. 1051 00:47:07,766 --> 00:47:09,876 {\an1}Basically, the oldest at the bottom, youngest on the top. 1052 00:47:09,900 --> 00:47:11,209 And even though some of these samples 1053 00:47:11,233 --> 00:47:13,576 {\an1}were only separated by a centimeter or two of sediment, 1054 00:47:13,600 --> 00:47:16,409 {\an1}they still maintain that order, and that's one of the, 1055 00:47:16,433 --> 00:47:17,576 {\an1}one of the, one of the key things that we wanted to see. 1056 00:47:17,600 --> 00:47:19,142 {\an1}And so it's not just what we see in the lab, 1057 00:47:19,166 --> 00:47:21,409 {\an1}but it's also what we see in the field taken together 1058 00:47:21,433 --> 00:47:22,876 {\an1}is really what makes this powerful. 1059 00:47:22,900 --> 00:47:25,642 JOHNSON: This is a huge discovery, how do you feel? 1060 00:47:25,666 --> 00:47:27,076 (laughs) Exhausted! 1061 00:47:27,100 --> 00:47:28,976 (laughing) 1062 00:47:29,000 --> 00:47:31,976 ♪ ♪ 1063 00:47:32,000 --> 00:47:33,842 JOHNSON (voiceover): If the results are correct, 1064 00:47:33,866 --> 00:47:36,076 {\an1}then these prints could have been left behind 1065 00:47:36,100 --> 00:47:39,400 {\an1}by some of the earliest known Americans. 1066 00:47:40,600 --> 00:47:44,342 Back at White Sands, I was curious to find out 1067 00:47:44,366 --> 00:47:48,742 {\an1}what Kim Charlie and Joe Watkins make of the discovery. 1068 00:47:48,766 --> 00:47:52,409 {\an1}So now that there are dates of 23,000 years ago 1069 00:47:52,433 --> 00:47:56,442 {\an1}with Native American footprints, how does that make you feel? 1070 00:47:56,466 --> 00:47:58,176 WATKINS: It's just amazing. 1071 00:47:58,200 --> 00:48:01,576 We talk about having always been here, 1072 00:48:01,600 --> 00:48:04,176 {\an7}it's just remarkable to put that much of a movement 1073 00:48:04,200 --> 00:48:05,376 {\an7}further back in time. 1074 00:48:05,400 --> 00:48:07,576 {\an1}So now we've added another 1075 00:48:07,600 --> 00:48:09,209 {\an1}6,000 to 8,000 years 1076 00:48:09,233 --> 00:48:11,809 {\an1}to what archaeologists have told us was 1077 00:48:11,833 --> 00:48:14,376 {\an1}the time depth of our history. 1078 00:48:14,400 --> 00:48:18,209 {\an1}And so this keeps putting that history back in the news, 1079 00:48:18,233 --> 00:48:20,409 {\an1}keeps telling people, "Well, yeah, 1080 00:48:20,433 --> 00:48:24,676 {\an1}you've been here 500 years, we've been here for 20,000." 1081 00:48:24,700 --> 00:48:26,976 {\an7}Here's our proof, you know? 1082 00:48:27,000 --> 00:48:31,242 {\an8}Footprints, footprints of our ancestors. 1083 00:48:31,266 --> 00:48:34,109 {\an1}You know, that goes to show, we were here. 1084 00:48:34,133 --> 00:48:37,476 {\an1}We were here on this earth a very long time ago. 1085 00:48:37,500 --> 00:48:40,709 ♪ ♪ 1086 00:48:40,733 --> 00:48:44,742 JOHNSON: But if humans were here 23,000 years ago, 1087 00:48:44,766 --> 00:48:47,266 {\an1}how did they get here? 1088 00:48:49,000 --> 00:48:51,142 At that time, 1089 00:48:51,166 --> 00:48:55,642 the corridor between the ice sheets did not exist. 1090 00:48:55,666 --> 00:48:58,642 {\an1}So humans might have followed the Pacific shoreline, 1091 00:48:58,666 --> 00:49:01,209 possibly by boat, 1092 00:49:01,233 --> 00:49:03,800 a route known as the "kelp highway." 1093 00:49:06,733 --> 00:49:08,909 But how exactly they would have made it here 1094 00:49:08,933 --> 00:49:12,333 {\an1}during the Ice Age is still unknown. 1095 00:49:14,500 --> 00:49:17,176 JOHNSON: These footprints tell us that people were here 1096 00:49:17,200 --> 00:49:19,242 {\an1}during the Last Glacial Maximum. 1097 00:49:19,266 --> 00:49:21,076 So how, how do you think they got here? 1098 00:49:21,100 --> 00:49:26,042 {\an1}WATKINS: I think probably the coastal highway is the best bet. 1099 00:49:26,066 --> 00:49:28,409 {\an1}Many old sites are going to be submerged under water now. 1100 00:49:28,433 --> 00:49:30,809 {\an1}So I, I think that's where we need to look. 1101 00:49:30,833 --> 00:49:33,276 ♪ ♪ 1102 00:49:33,300 --> 00:49:34,642 JOHNSON (voiceover): Whatever the answer, 1103 00:49:34,666 --> 00:49:37,009 {\an1}there's no doubt that these astonishing discoveries 1104 00:49:37,033 --> 00:49:39,876 {\an7}are another step forward 1105 00:49:39,900 --> 00:49:42,809 {\an7}in scientists' understanding of human history. 1106 00:49:42,833 --> 00:49:46,642 {\an1}And perhaps they could also shed new light on humans' role 1107 00:49:46,666 --> 00:49:49,600 in the extinction of Ice Age animals. 1108 00:49:51,233 --> 00:49:53,409 {\an1}So where does this leave us? 1109 00:49:53,433 --> 00:49:56,542 {\an1}For many years, we thought that the Ice Age animals went extinct 1110 00:49:56,566 --> 00:49:59,209 {\an1}about the same time that people got to North America. 1111 00:49:59,233 --> 00:50:02,576 {\an1}Now this site is telling us something very different. 1112 00:50:02,600 --> 00:50:04,976 {\an1}Basically what we're seeing is that humans were here 1113 00:50:05,000 --> 00:50:08,476 {\an1}more than 10,000 years before the extinction of the animals. 1114 00:50:08,500 --> 00:50:11,342 {\an1}So the question of was the extinction caused by climate, 1115 00:50:11,366 --> 00:50:13,442 or people, or both, 1116 00:50:13,466 --> 00:50:17,242 {\an1}has just become a much more complex problem to solve. 1117 00:50:17,266 --> 00:50:19,376 ♪ ♪ 1118 00:50:19,400 --> 00:50:22,842 {\an1}One theory is that when humans arrived on this continent, 1119 00:50:22,866 --> 00:50:24,609 {\an1}their numbers were too small 1120 00:50:24,633 --> 00:50:29,409 to make a big impact on the wildlife. 1121 00:50:29,433 --> 00:50:32,776 But at some point, populations increased, 1122 00:50:32,800 --> 00:50:36,342 and they developed better hunting techniques. 1123 00:50:36,366 --> 00:50:40,100 {\an1}Was this what eventually spelled the end for the animals? 1124 00:50:41,466 --> 00:50:43,209 {\an1}People have always thought it was either 1125 00:50:43,233 --> 00:50:44,876 {\an8}climate or people that caused 1126 00:50:44,900 --> 00:50:47,042 {\an7}the extinction of the Ice Age megafauna. 1127 00:50:47,066 --> 00:50:48,676 What do you think? 1128 00:50:48,700 --> 00:50:51,876 {\an1}You know, I... we really don't know yet. 1129 00:50:51,900 --> 00:50:54,476 {\an1}But what we do see, you know, without a reasonable doubt, 1130 00:50:54,500 --> 00:50:56,409 {\an1}is that, you know, around 12,000 years, 1131 00:50:56,433 --> 00:50:58,076 {\an1}the area starts to dry out, 1132 00:50:58,100 --> 00:51:00,642 {\an1}the lake dries up and then the dunes form. 1133 00:51:00,666 --> 00:51:02,909 {\an1}So climate change might have been influencing that as well. 1134 00:51:02,933 --> 00:51:04,609 {\an1}Maybe someday we'll, we'll find out. 1135 00:51:04,633 --> 00:51:06,476 {\an1}We might not ever learn. 1136 00:51:06,500 --> 00:51:09,376 {\an1}But, but you know, the exciting thing about White Sands 1137 00:51:09,400 --> 00:51:11,676 {\an1}is there's thousands of prints to study. 1138 00:51:11,700 --> 00:51:13,809 {\an1}So, you know, the secret might be locked there 1139 00:51:13,833 --> 00:51:14,810 {\an1}somewhere in the sand. 1140 00:51:14,834 --> 00:51:18,342 {\an8}♪ ♪ 1141 00:51:18,366 --> 00:51:19,809 {\an8}JOHNSON: The unique preservation 1142 00:51:19,833 --> 00:51:24,442 {\an7}of these ancient footprints could yield more clues 1143 00:51:24,466 --> 00:51:28,209 {\an8}about the lives of Ice Age Americans. 1144 00:51:28,233 --> 00:51:31,809 {\an8}SPRINGER: We're very excited because it's, it's kind of 1145 00:51:31,833 --> 00:51:33,209 {\an1}the tip of the iceberg, you know? 1146 00:51:33,233 --> 00:51:34,609 {\an1}White Sands is still there. 1147 00:51:34,633 --> 00:51:35,876 {\an1}Those tracks are still there. 1148 00:51:35,900 --> 00:51:39,009 {\an1}They're eroding out every day, every minute. 1149 00:51:39,033 --> 00:51:42,276 {\an1}And we get the opportunity to go back and, and to learn more. 1150 00:51:42,300 --> 00:51:43,509 JOHNSON: So the research goes on, then. 1151 00:51:43,533 --> 00:51:44,942 {\an1}Yeah, it goes on, sure. 1152 00:51:44,966 --> 00:51:46,442 {\an1}PIGATI: Yeah, this is just the beginning, that's exactly right. 1153 00:51:46,466 --> 00:51:48,409 {\an1}It's a tremendous opportunity. 1154 00:51:48,433 --> 00:51:51,442 {\an1}It... it's opening up the world of archaeology 1155 00:51:51,466 --> 00:51:53,076 {\an1}way beyond where it's been. 1156 00:51:53,100 --> 00:51:56,442 {\an1}It's going to give a new generation of archaeologists 1157 00:51:56,466 --> 00:51:58,842 {\an1}something more to shoot for, 1158 00:51:58,866 --> 00:52:00,976 {\an1}to see whether we can go back 1159 00:52:01,000 --> 00:52:03,142 {\an1}any farther than 23,000 years, 1160 00:52:03,166 --> 00:52:07,942 {\an1}or whether this, in and of itself, is the threshold. 1161 00:52:07,966 --> 00:52:13,066 ♪ ♪ 1162 00:52:32,900 --> 00:52:40,433 ♪ ♪ 1163 00:52:47,666 --> 00:52:52,509 {\an8}ANNOUNCER: To order this program on DVD, visit ShopPBS. 1164 00:52:52,533 --> 00:52:55,242 {\an7}Or call 1-800-PLAY-PBS. 1165 00:52:55,266 --> 00:52:58,109 {\an8}Episodes of "NOVA" are available with Passport. 1166 00:52:58,133 --> 00:53:01,909 {\an7}"NOVA" is also available on Amazon Prime Video. 1167 00:53:01,933 --> 00:53:07,133 ♪ ♪ 1168 00:53:15,933 --> 00:53:23,100 ♪ ♪