1 00:00:02,920 --> 00:00:04,920 NARRATOR: Deep inside the labyrinth 2 00:00:05,000 --> 00:00:07,920 of a flooded cave system. 3 00:00:08,000 --> 00:00:10,160 ALBERTO: All of a sudden, the floor just drops. 4 00:00:10,680 --> 00:00:14,000 NARRATOR: Divers come across human remains. 5 00:00:14,080 --> 00:00:17,440 ALBERTO: You can see these dark eye sockets kinda looking back at us. 6 00:00:17,520 --> 00:00:21,200 NARRATOR: And the bones of giant prehistoric creatures. 7 00:00:21,280 --> 00:00:26,240 DOMINIQUE: Saber-tooth cats, bears, giant ground sloths. 8 00:00:26,320 --> 00:00:29,000 NARRATOR: Discoveries that could revolutionize our 9 00:00:29,080 --> 00:00:33,800 understanding of how the first humans came to the Americas. 10 00:00:33,880 --> 00:00:35,960 LOREN: They must have come here another way. 11 00:00:38,240 --> 00:00:41,400 (theme music plays) 12 00:00:51,680 --> 00:00:55,440 ALBERTO (off-screen): We have 800 miles of underwater tunnels 13 00:00:55,520 --> 00:00:57,160 that have been mapped. 14 00:00:57,920 --> 00:01:02,040 We think there's another half still to be discovered. 15 00:01:11,640 --> 00:01:15,160 NARRATOR: A team of divers is exploring the world's largest 16 00:01:15,240 --> 00:01:18,320 underground flooded cave system. 17 00:01:18,400 --> 00:01:21,440 ALBERTO (off-screen): It's like a labyrinth of tunnels everywhere, 18 00:01:21,520 --> 00:01:25,640 almost like a Swiss cheese in the ground, full with, with water. 19 00:01:26,880 --> 00:01:30,440 NARRATOR: Their aim, to survey this lost world, 20 00:01:30,520 --> 00:01:34,280 sealed off from humanity since the Ice Age. 21 00:01:44,680 --> 00:01:46,880 ALBERTO (off-screen): The Yucatán is special, 22 00:01:46,960 --> 00:01:49,920 because all the cave here were once dry. 23 00:01:50,000 --> 00:01:52,560 We know this because of the stalagmites and the 24 00:01:52,640 --> 00:01:56,400 stalactites which only form in a dry cave. 25 00:01:56,480 --> 00:02:00,880 About 12,000 years ago, at the end of the Ice Age, 26 00:02:00,960 --> 00:02:05,480 the ice sheet melted and the cave began to flood. 27 00:02:05,560 --> 00:02:09,080 NARRATOR: Now, these flooded caves pose grave risks 28 00:02:09,160 --> 00:02:10,760 to the divers. 29 00:02:10,840 --> 00:02:13,000 ALBERTO: Caves can be very dangerous. 30 00:02:13,080 --> 00:02:16,040 ALBERTO (off-screen): You have, you know, going in an environment where, 31 00:02:16,120 --> 00:02:18,760 if you have a problem, you cannot ascend. 32 00:02:20,920 --> 00:02:24,840 The tunnel that you're traveling is, is totally dark. 33 00:02:27,040 --> 00:02:30,040 Your lights now not have a way to see. 34 00:02:30,120 --> 00:02:32,320 If you go in a small area, you could get trapped 35 00:02:32,400 --> 00:02:35,040 inside the cave, so there's a lot of risk. 36 00:02:37,600 --> 00:02:41,720 NARRATOR: The team's goal is to map this complex network. 37 00:02:43,560 --> 00:02:45,280 ALBERTO (off-screen): When we go into these tunnels, 38 00:02:45,360 --> 00:02:49,320 we do a very simple map of the cave. 39 00:02:49,400 --> 00:02:51,280 Then we bring the camera, and then what we do 40 00:02:51,360 --> 00:02:53,000 is we take a lot of images. 41 00:02:54,880 --> 00:03:00,040 NARRATOR: It's taken 150 hours to map as far as this point, 42 00:03:00,120 --> 00:03:04,600 and now the divers stop. 43 00:03:05,040 --> 00:03:06,760 ALBERTO: All of a sudden the floor just drops. 44 00:03:08,000 --> 00:03:10,920 ALBERTO (off-screen): We have these really powerful underwater lights, 45 00:03:11,000 --> 00:03:13,920 and all you can see was darkness. 46 00:03:15,480 --> 00:03:20,160 So, like, the biggest, darkest hole we've seen on the cave. 47 00:03:22,160 --> 00:03:25,840 NARRATOR: Using the divers' own data and imagery, 48 00:03:25,920 --> 00:03:29,280 the scale of the abyss becomes clear. 49 00:03:37,840 --> 00:03:39,400 ALBERTO (off-screen): If we were to drain the water, 50 00:03:39,480 --> 00:03:44,080 we would see these bell-shaped structure, 51 00:03:44,160 --> 00:03:48,880 maybe, like a football field stadium kinda size. 52 00:03:54,560 --> 00:03:59,160 NARRATOR: They name the vast cave "Hoyo Negro"; 53 00:03:59,240 --> 00:04:01,960 "Black Hole." 54 00:04:04,400 --> 00:04:06,720 ALBERTO (off-screen): As we descended into the pit, 55 00:04:06,800 --> 00:04:08,840 we were moving our lights, 56 00:04:08,920 --> 00:04:11,720 trying to figure out what was down there. 57 00:04:18,880 --> 00:04:22,120 NARRATOR: Anything Alberto and his team find here will come 58 00:04:22,200 --> 00:04:27,120 from pre-history, when the abyss was a dry cave. 59 00:04:32,360 --> 00:04:34,560 ALBERTO (off-screen): And then, then we saw a bone. 60 00:04:36,600 --> 00:04:39,640 It was a really long, tall bone. 61 00:04:39,720 --> 00:04:43,800 We moved around it, and then we saw another bone. 62 00:04:46,600 --> 00:04:50,440 We started noticing that there were, there were remains 63 00:04:50,520 --> 00:04:52,720 all over the place on the floor. 64 00:04:55,520 --> 00:04:59,080 Whatever they were, it has to have been a really big animal. 65 00:05:02,680 --> 00:05:05,720 ALBERTO (off-screen): We knew we had found something really important here, 66 00:05:05,800 --> 00:05:08,360 so we mapped everything in the cave, 67 00:05:08,440 --> 00:05:12,920 recorded the exact locations of the bones and took photos, 68 00:05:13,000 --> 00:05:15,400 and then we sent all our data to our 69 00:05:15,480 --> 00:05:17,440 colleagues in California. 70 00:05:24,000 --> 00:05:26,880 DOMINIQUE: Our goal is to capture these places, 71 00:05:26,960 --> 00:05:31,760 these wild places, using our visualization systems. 72 00:05:35,880 --> 00:05:39,040 VID: Okay, I'm just gonna go through the different views. 73 00:05:46,760 --> 00:05:49,720 So, we're now just kinda reliving the dive paths. 74 00:05:50,560 --> 00:05:54,840 NARRATOR: In 2014, Dominique Rissolo and his team 75 00:05:54,920 --> 00:05:59,440 begin to process the divers' mapping data and images. 76 00:05:59,520 --> 00:06:04,880 Their aim is to create a 3D digital replica of Hoyo Negro, 77 00:06:04,960 --> 00:06:07,640 which they can explore from dry land. 78 00:06:07,720 --> 00:06:11,720 DOMINIQUE (off-screen): The divers have tremendous experience in doing 79 00:06:11,800 --> 00:06:14,800 different kinds of documentation underwater, 80 00:06:14,880 --> 00:06:18,880 and we're able to take all of those images, and, 81 00:06:18,960 --> 00:06:20,640 through computer vision algorithms, 82 00:06:20,720 --> 00:06:24,000 translate them into a 3D model. 83 00:06:24,080 --> 00:06:26,320 And it's really, essentially, a, a point cloud, 84 00:06:26,400 --> 00:06:28,040 a cloud of points. 85 00:06:30,320 --> 00:06:35,160 VID (off-screen): So far we have around 15 billion reconstructed points. 86 00:06:36,680 --> 00:06:39,440 The exciting thing is it grows every year, 87 00:06:39,520 --> 00:06:41,320 so every time they go diving, take pictures, 88 00:06:41,400 --> 00:06:43,120 we run new reconstructions. 89 00:06:43,200 --> 00:06:44,640 We just add to the set. 90 00:06:46,800 --> 00:06:49,000 DOMINIQUE (off-screen): The way that we can create maybe a more 91 00:06:49,080 --> 00:06:54,240 photo-realistic 3D model is by then texturing those points 92 00:06:54,320 --> 00:06:56,720 with the original photographs. 93 00:06:56,800 --> 00:07:00,480 DOMINIQUE (off-screen): So, these are high-resolution images that can be essentially 94 00:07:00,560 --> 00:07:03,840 draped on to this 3D point cloud. 95 00:07:14,400 --> 00:07:17,800 Wow! So, here we are at the bottom of Hoyo Negro. 96 00:07:19,080 --> 00:07:20,840 JOEL (off-screen): This is one of the most powerful virtual reality 97 00:07:20,920 --> 00:07:22,960 systems in the world. 98 00:07:26,440 --> 00:07:31,080 Being inside the SunCAVE is similar to being on the dive itself, 99 00:07:31,160 --> 00:07:33,240 with the exception that you're able to be well lit. 100 00:07:33,320 --> 00:07:35,440 You're able to see everything that you can't see. 101 00:07:37,120 --> 00:07:40,360 DOMINIQUE (off-screen): This is essentially an interactive digital twin 102 00:07:40,440 --> 00:07:44,600 that enables us to come here and do virtual dives, 103 00:07:44,680 --> 00:07:47,520 and sometimes even find new animals. 104 00:07:47,600 --> 00:07:50,680 DOMINIQUE (off-screen): Finding new animals in a virtual cave, right? 105 00:07:50,760 --> 00:07:54,640 So, exploring a real cave by using a virtual one. 106 00:08:00,480 --> 00:08:04,480 The first big animal that the divers came upon was right 107 00:08:04,560 --> 00:08:07,080 here at this gomphothere. 108 00:08:09,080 --> 00:08:12,120 DOMINIQUE (off-screen): It wasn't as if it was just this proboscidean, 109 00:08:12,200 --> 00:08:14,360 this relative of the elephant. 110 00:08:15,600 --> 00:08:19,320 It's such an incredible diversity of Ice Age fauna. 111 00:08:20,480 --> 00:08:26,200 Bears, saber-tooth cats, 112 00:08:27,400 --> 00:08:29,640 giant ground sloths. 113 00:08:32,840 --> 00:08:34,840 DOMINIQUE (off-screen): Just amazing! 114 00:08:34,920 --> 00:08:39,320 So, Joel, if you take us sort of on to the wall of the cave here, 115 00:08:39,400 --> 00:08:42,760 we can see this saber-tooth cat emerge, 116 00:08:42,840 --> 00:08:45,280 smilodon fatalis. 117 00:08:45,360 --> 00:08:48,840 Clinging to the wall we see, you know, another scapula, 118 00:08:48,920 --> 00:08:52,080 of course, the scapula over here of the giant ground sloth, 119 00:08:52,160 --> 00:08:55,000 it's ribs. 120 00:08:56,440 --> 00:08:58,120 NARRATOR: By examining the bones, 121 00:08:58,200 --> 00:09:03,440 Dominique's colleagues identify at least 16 Ice Age species. 122 00:09:06,320 --> 00:09:07,720 DOMINIQUE (off-screen): Whether they were looking for water, 123 00:09:07,800 --> 00:09:10,360 or to build a den, or even to hunt, 124 00:09:10,440 --> 00:09:14,280 these are massive animals that were walking through these passageways, 125 00:09:14,360 --> 00:09:17,560 coming to the edge of this, this precipice and 126 00:09:17,640 --> 00:09:20,360 making their way to the bottom of this pit. 127 00:09:20,440 --> 00:09:25,080 It's a really wonderful view into what the planet was like 128 00:09:25,160 --> 00:09:27,440 at a time thousands of years ago. 129 00:09:31,000 --> 00:09:33,760 DOMINIQUE (off-screen): As incredible as those discoveries were, 130 00:09:33,840 --> 00:09:36,320 that wasn't the only thing they found that day. 131 00:09:43,000 --> 00:09:47,200 ♪ ♪ 132 00:09:47,640 --> 00:09:51,240 ALBERTO (off-screen): We were swimming at the bottom of the site, 133 00:09:51,320 --> 00:09:52,920 looking at the animal remains, 134 00:09:53,000 --> 00:09:54,720 and then all of a sudden my friend, 135 00:09:54,800 --> 00:09:57,760 Alex, just moved his light and he pointed in 136 00:09:57,840 --> 00:10:00,080 a particular direction. 137 00:10:01,760 --> 00:10:03,760 NARRATOR: Within touching distance, 138 00:10:03,840 --> 00:10:06,720 at the bottom of the vast, flooded cave system, 139 00:10:06,800 --> 00:10:10,360 dive, Alberto Nava and his team are about to make 140 00:10:10,440 --> 00:10:13,640 the discovery of a lifetime. 141 00:10:14,480 --> 00:10:17,920 ALBERTO (off-screen): We see these just beautiful cranium, 142 00:10:18,000 --> 00:10:22,200 its just sitting, sitting upside down. 143 00:10:23,520 --> 00:10:26,080 You can see these dark eye sockets kinda, kinda looking 144 00:10:26,160 --> 00:10:28,240 back at us. 145 00:10:29,960 --> 00:10:32,520 DOMINIQUE (off-screen): My, my, my blood ran cold. 146 00:10:32,600 --> 00:10:35,760 I mean, my, the hairs stood on end. 147 00:10:38,880 --> 00:10:41,640 ALBERTO (off-screen): I don't think I'll find anything like that in my 148 00:10:41,720 --> 00:10:43,200 exploration life. 149 00:10:43,280 --> 00:10:46,160 This is probably the best it's ever gonna get. 150 00:10:46,760 --> 00:10:48,280 DOMINIQUE (off-screen): All these things come to mind. 151 00:10:48,360 --> 00:10:49,880 Who was this person? 152 00:10:49,960 --> 00:10:52,840 You know, how did they come to be here? 153 00:10:52,920 --> 00:10:56,680 When did they arrive at the bottom of this pit? 154 00:10:58,640 --> 00:11:00,440 HELENA: Let's remember, 155 00:11:00,520 --> 00:11:02,840 we are a prestigious project 156 00:11:02,920 --> 00:11:04,800 and a great team. 157 00:11:05,600 --> 00:11:07,160 NARRATOR: To help find the answers, 158 00:11:07,240 --> 00:11:10,040 the team consults experts from around the world, 159 00:11:10,120 --> 00:11:15,080 led by Mexico's National Institute of Anthropology and History. 160 00:11:15,160 --> 00:11:18,000 DOMINIQUE: We have now over 30 scientists 161 00:11:18,080 --> 00:11:19,680 and engineers involved. 162 00:11:19,760 --> 00:11:21,880 DOMINIQUE (off-screen): The paleontologists, 163 00:11:21,960 --> 00:11:24,400 the archaeologists and anthropologists, 164 00:11:24,480 --> 00:11:28,200 who are all helping to put together this puzzle. 165 00:11:30,200 --> 00:11:32,600 JAMES (over computer): We have a fairly consistent 3,000-year 166 00:11:32,680 --> 00:11:34,400 offset between. 167 00:11:34,480 --> 00:11:36,960 DOMINIQUE (off-screen): As a project, we made the decision to reach out 168 00:11:37,040 --> 00:11:41,800 to Jim Chatters, who had the experience and expertise we 169 00:11:41,880 --> 00:11:46,560 really needed to understand the significance of the site 170 00:11:46,640 --> 00:11:48,440 of Hoyo Negro and everything it contained. 171 00:11:51,080 --> 00:11:52,960 JAMES: Well, you just don't see this, 172 00:11:53,040 --> 00:11:57,800 this kind of preservation, so it's just unbelievable quality. 173 00:12:03,320 --> 00:12:05,720 NARRATOR: The first question on the team's mind, 174 00:12:05,800 --> 00:12:09,880 "Who is this person at the bottom of the cave?" 175 00:12:13,840 --> 00:12:16,760 DOMINIQUE (off-screen): I shared photographs of the discoveries, 176 00:12:16,840 --> 00:12:20,000 and his eyes lit up. 177 00:12:20,080 --> 00:12:22,400 I could see his hands trembling a little bit. 178 00:12:22,480 --> 00:12:24,000 JAMES: And here's our human. 179 00:12:27,640 --> 00:12:34,320 The skeleton, is, it's a diary of someone's life, okay, 180 00:12:34,400 --> 00:12:36,720 and it's especially a diary of their early years. 181 00:12:39,720 --> 00:12:41,880 This is a really good picture here. 182 00:12:43,400 --> 00:12:46,000 JAMES (off-screen): Here's the telling piece. 183 00:12:46,080 --> 00:12:49,240 I can see, first of all, that a feature in the base of the 184 00:12:49,320 --> 00:12:52,320 skull called the "basilar suture" was still open, 185 00:12:52,400 --> 00:12:56,280 and that tends to close somewhere around the 20s. 186 00:12:57,840 --> 00:13:00,280 And it was not only a full-size skull, 187 00:13:00,360 --> 00:13:03,280 but the, the third molars had already erupted. 188 00:13:04,920 --> 00:13:07,760 JAMES (off-screen): So, it's a fully formed tooth, or nearly fully formed, 189 00:13:07,840 --> 00:13:11,280 which puts this more than 15 years old. 190 00:13:11,960 --> 00:13:14,280 JAMES (off-screen): In looking at this right away I'm thinking, 191 00:13:14,360 --> 00:13:18,320 16 to 19 years is the most likely age of this individual. 192 00:13:21,920 --> 00:13:23,840 JAMES (off-screen): To determine the sex of a skull, 193 00:13:23,920 --> 00:13:26,600 you're looking at how rugged it is, mainly. 194 00:13:28,160 --> 00:13:30,440 In this case, what I did was I look at the mastoid processes, 195 00:13:30,520 --> 00:13:35,160 and that's the position on the skull here where the large 196 00:13:35,240 --> 00:13:38,960 neck muscles attach, and they tend to be large in males 197 00:13:39,040 --> 00:13:40,200 and small in females. 198 00:13:40,280 --> 00:13:42,280 And in this case, they were very small. 199 00:13:44,320 --> 00:13:47,280 JAMES (off-screen): I asked Dominique if anyone had told him what he had there, 200 00:13:47,360 --> 00:13:49,720 and he said, "No, they hadn't." 201 00:13:49,800 --> 00:13:51,440 And I said, 202 00:13:51,520 --> 00:13:54,240 "Well, what you've got here is, is the bones of a teenage girl, 203 00:13:54,320 --> 00:13:58,240 and a bunch of really large megafauna." 204 00:14:01,160 --> 00:14:05,160 This is the first time we have a human skull in direct association 205 00:14:05,240 --> 00:14:09,240 with the skeleton of an extinct animal in the Americas, period. 206 00:14:09,320 --> 00:14:11,600 That's really exciting. 207 00:14:14,000 --> 00:14:16,080 NARRATOR: Over successive dives, 208 00:14:16,160 --> 00:14:19,200 the team finds and scans more bones belonging 209 00:14:19,280 --> 00:14:21,720 to the teenage girl. 210 00:14:21,800 --> 00:14:26,120 By 2013, they've documented her near complete skeleton, 211 00:14:26,200 --> 00:14:30,320 and she has become more than simply an archaeological find. 212 00:14:30,400 --> 00:14:33,240 DOMINIQUE: Here we are in Hoyo Negro. 213 00:14:33,320 --> 00:14:34,440 JAMES: Yeah. 214 00:14:34,520 --> 00:14:35,800 Wow! 215 00:14:35,880 --> 00:14:38,240 I've always wanted to dive this. 216 00:14:38,320 --> 00:14:40,800 JAMES (off-screen): This is about the closest I'm ever gonna come, I think. 217 00:14:44,840 --> 00:14:48,200 She's spread over about a 16 feet span here. 218 00:14:52,520 --> 00:14:57,440 What I stressed with the divers was that basically they 219 00:14:57,520 --> 00:15:00,880 needed to remember the personhood of these bones. 220 00:15:02,840 --> 00:15:04,200 ALBERTO (off-screen): If you give it a name, 221 00:15:04,280 --> 00:15:08,880 you, you become more caring about this skeleton, 222 00:15:08,960 --> 00:15:11,800 and it goes from a skeleton to becoming a person. 223 00:15:14,120 --> 00:15:18,160 ALBERTO (off-screen): We had a lot of candidates for names. 224 00:15:18,240 --> 00:15:20,560 We decided to call it "Naia." 225 00:15:25,360 --> 00:15:26,760 JAMES: Naiads were water 226 00:15:26,840 --> 00:15:29,320 spirits in Greek mythology. 227 00:15:29,400 --> 00:15:32,240 They were the, the female spirits that watched over small bodies 228 00:15:32,320 --> 00:15:35,760 of water, so it seemed a very fitting name for her. 229 00:15:39,200 --> 00:15:42,800 NARRATOR: Naia's remains are found close to Ice Age mammals, 230 00:15:42,880 --> 00:15:45,880 but that isn't enough to prove that Naia herself 231 00:15:45,960 --> 00:15:48,320 is prehistoric. 232 00:15:49,280 --> 00:15:53,400 JAMES: Our goal with Naia was to collect a specimen from the 233 00:15:53,480 --> 00:15:55,560 skeleton to use for radiocarbon dating. 234 00:15:59,120 --> 00:16:01,760 JAMES (off-screen): We chose to do one third molar, 235 00:16:01,840 --> 00:16:03,840 because third molars are often very simply rooted and 236 00:16:03,920 --> 00:16:05,720 therefore easy to take out of a skeleton. 237 00:16:08,120 --> 00:16:11,000 DOMINIQUE: There are a number of problems inherent in, in carbon dating, 238 00:16:11,080 --> 00:16:13,120 and those can include contamination. 239 00:16:15,080 --> 00:16:18,160 DOMINIQUE (off-screen): It was not a foregone conclusion that we were going 240 00:16:18,240 --> 00:16:20,640 to get a viable date from Naia. 241 00:16:22,840 --> 00:16:26,680 JAMES (off-screen): We ran dates independently in two laboratories, 242 00:16:26,760 --> 00:16:29,480 fully expecting the dates to be completely 243 00:16:29,560 --> 00:16:32,080 different from each other, and it came back within 15 years. 244 00:16:33,800 --> 00:16:36,600 And between those, those translate to 245 00:16:36,680 --> 00:16:41,120 close to 12,900 years ago. 246 00:16:43,600 --> 00:16:45,520 JAMES (off-screen): It was pretty exciting to find out, 247 00:16:45,600 --> 00:16:48,360 because only one other skeleton at that time had 248 00:16:48,440 --> 00:16:51,960 dated that old, and all that there was of that individual 249 00:16:52,040 --> 00:16:53,800 was one bone. 250 00:16:53,880 --> 00:16:55,280 Not even a complete bone. 251 00:16:56,680 --> 00:16:59,520 JAMES (off-screen) :The fact that Naia's skeleton was so complete makes her an 252 00:16:59,600 --> 00:17:01,480 incredibly rare find. 253 00:17:01,960 --> 00:17:04,840 NARRATOR: And, as the oldest near complete skeleton ever 254 00:17:04,920 --> 00:17:08,240 found in the Americas, Naia could provide answers 255 00:17:08,320 --> 00:17:13,360 about early humans living here, but to protect her remains, 256 00:17:13,440 --> 00:17:17,320 the team must first remove her from the cave. 257 00:17:25,920 --> 00:17:29,080 ALBERTO: So, it's been, you know, six, seven years of adventure, 258 00:17:29,160 --> 00:17:31,520 and although we didn't really 259 00:17:31,600 --> 00:17:35,400 wanna take any human remains, we have to do it to protect it, 260 00:17:35,480 --> 00:17:37,360 and that's kind of what the day is all about, 261 00:17:37,440 --> 00:17:40,360 protecting Naia and her remains. 262 00:17:41,680 --> 00:17:43,880 NARRATOR: The operation to recover Naia's fragile 263 00:17:43,960 --> 00:17:47,480 skeleton begins with her skull. 264 00:17:47,560 --> 00:17:50,120 It is fraught with risk. 265 00:17:50,200 --> 00:17:51,640 JAMES: Well, we're doing a pre-dive practice, 266 00:17:51,720 --> 00:17:54,120 or the, the procedures drill. 267 00:17:55,560 --> 00:17:59,200 NARRATOR: Jim rehearses the recovery with a replica skull. 268 00:18:00,480 --> 00:18:03,280 JAMES: My endeavor was designing how Naia's bones 269 00:18:03,360 --> 00:18:05,240 were gonna be safely removed. 270 00:18:05,320 --> 00:18:07,720 JAMES (off-screen): Your strongest part is here. 271 00:18:07,800 --> 00:18:08,960 SUSAN (off-screen): Mm-hmm. 272 00:18:09,040 --> 00:18:10,720 JAMES: Your weakest points are here and here, 273 00:18:10,800 --> 00:18:12,320 so we must protect them. 274 00:18:12,400 --> 00:18:14,280 JAMES (off-screen): This was a big deal. 275 00:18:14,360 --> 00:18:18,160 I mean, imagine, I'm the one responsible for making sure 276 00:18:18,240 --> 00:18:21,760 that thing doesn't get destroyed in the collection process, 277 00:18:21,840 --> 00:18:24,320 so I was just a little on the nervous side. 278 00:18:25,520 --> 00:18:27,840 And just gently, chin first. 279 00:18:28,200 --> 00:18:29,400 SUSAN (off-screen): Okay. 280 00:18:29,480 --> 00:18:30,880 JAMES (off-screen): And release. 281 00:18:31,440 --> 00:18:35,600 The reason Susan was the one to handle the bones had in 282 00:18:35,680 --> 00:18:39,520 part to do with the fact that she had very steady hands, 283 00:18:39,600 --> 00:18:44,800 but she also felt a linkage to the young woman who was in the cave. 284 00:18:44,880 --> 00:18:47,600 SUSAN: And I just feel very connected with her spirit. 285 00:18:48,440 --> 00:18:53,360 I feel like she's been there a long time and is ready 286 00:18:53,440 --> 00:18:54,760 to go home. 287 00:19:03,440 --> 00:19:06,280 ALBERTO: There was one chance and we had to get it right. 288 00:19:16,200 --> 00:19:17,960 ALBERTO (off-screen): The moment Susan picked up the skull, 289 00:19:18,040 --> 00:19:20,600 everybody's breathing stopped. 290 00:19:30,640 --> 00:19:35,240 JAMES (off-screen): That was a really tense three hours of waiting, 291 00:19:35,320 --> 00:19:39,240 waiting to see if what would be in the box when it came up? 292 00:19:39,320 --> 00:19:42,520 Was it a complete skull or a whole pile of bone fragments? 293 00:19:48,720 --> 00:19:50,440 Here they come! 294 00:19:51,440 --> 00:19:53,160 My, oh, my. 295 00:19:53,240 --> 00:19:55,440 JAMES (off-screen): Okay, Susan's on the left, Beto's on the right. 296 00:20:01,280 --> 00:20:04,840 DOMINIQUE (off-screen): She comes to the surface, and you know that, 297 00:20:04,920 --> 00:20:07,760 as an archaeologist, you're never gonna have another 298 00:20:07,840 --> 00:20:08,960 experience like this. 299 00:20:09,040 --> 00:20:10,520 I mean, this is it. 300 00:20:17,520 --> 00:20:20,040 Okay, go ahead. Okay, she's fine in there. 301 00:20:20,120 --> 00:20:22,360 Nice! 302 00:20:22,440 --> 00:20:25,880 JAMES (off-screen): I remember getting down and peeking in the end and seeing 303 00:20:25,960 --> 00:20:29,920 a whole skull there, and tremendous elation 304 00:20:30,000 --> 00:20:31,640 that came from that. 305 00:20:31,720 --> 00:20:32,920 Welcome, Naia! 306 00:20:33,000 --> 00:20:34,720 We got her out and we got her out whole. 307 00:20:34,800 --> 00:20:36,880 ALBERTO: Jim Chatters, it's good to meet you. 308 00:20:36,960 --> 00:20:38,880 JAMES: Gracias! Gracias! Good job, man. 309 00:20:38,960 --> 00:20:41,840 JAMES (off-screen): I've been at this for 60-plus years, 310 00:20:41,920 --> 00:20:45,040 and that was the top moment in all that time. 311 00:20:46,040 --> 00:20:47,360 SUSAN: Hey! 312 00:20:47,960 --> 00:20:50,000 JAMES (off-screen): We cried. 313 00:20:56,080 --> 00:20:59,240 NARRATOR: Naia's remains give the team an unprecedented 314 00:20:59,320 --> 00:21:03,920 opportunity to learn about America's early humans. 315 00:21:05,000 --> 00:21:09,400 A key question is whether Naia is a direct ancestor to 316 00:21:09,480 --> 00:21:12,360 modern Native Americans? 317 00:21:12,440 --> 00:21:17,320 In a replica of her skeleton, Jim looks for clues. 318 00:21:18,800 --> 00:21:21,440 JAMES (off-screen): The characteristics that jumped out at me was the 319 00:21:21,520 --> 00:21:24,040 very distinct angularity to the back of her skull, 320 00:21:24,120 --> 00:21:28,920 and the tendency for her face to project forward. 321 00:21:29,000 --> 00:21:31,440 NARRATOR: These are not common features of modern 322 00:21:31,520 --> 00:21:33,320 Native Americans. 323 00:21:33,400 --> 00:21:35,840 JAMES: The contrast with more recent Native American skulls 324 00:21:35,920 --> 00:21:37,640 represented by these casts here. 325 00:21:37,720 --> 00:21:38,920 Here's a female. 326 00:21:39,000 --> 00:21:41,480 You can see a much more rounded skull. 327 00:21:41,560 --> 00:21:44,200 The face, in a similar position, 328 00:21:44,280 --> 00:21:46,240 is much more straight up and down. 329 00:21:46,320 --> 00:21:50,240 NARRATOR: When the team turns to facial reconstruction technology, 330 00:21:50,320 --> 00:21:52,360 the mystery deepens. 331 00:21:52,440 --> 00:21:57,240 JAMES: What we got, we went from the printed skull here, 332 00:21:57,320 --> 00:22:00,880 and then this is how she turned out. 333 00:22:00,960 --> 00:22:02,400 DOMINIQUE: Wow! 334 00:22:06,400 --> 00:22:09,240 JAMES (off-screen): I didn't expect her to look like she did. 335 00:22:09,320 --> 00:22:15,320 She almost looks like a South African busman from the Kalahari Desert, 336 00:22:15,400 --> 00:22:18,320 or someone outta South East Asia. 337 00:22:20,040 --> 00:22:22,880 Her eyes are wider set, her nose is broader, 338 00:22:22,960 --> 00:22:27,840 so those are all things that were different from what I'm used to. 339 00:22:29,200 --> 00:22:30,560 DOMINIQUE (off-screen): There's a mystery then, 340 00:22:30,640 --> 00:22:35,520 if she appears to be so different from the ancestors 341 00:22:35,600 --> 00:22:39,040 of modern Native Americans, where did she come from? 342 00:22:41,440 --> 00:22:46,040 NARRATOR: To find out, the team tests Naia's DNA. 343 00:22:50,040 --> 00:22:52,040 JAMES: When I got the result back, 344 00:22:52,120 --> 00:22:53,520 I was very happy that we got a result, 345 00:22:53,600 --> 00:22:56,920 but as happy as I was to get the result, 346 00:22:57,000 --> 00:22:58,720 it was not the result I expected. 347 00:23:00,120 --> 00:23:04,000 JAMES (off-screen): What it showed was that although Naia's skull seemed 348 00:23:04,080 --> 00:23:05,960 different from modern Native Americans, 349 00:23:06,040 --> 00:23:08,280 they still shared a genetic background. 350 00:23:08,360 --> 00:23:10,680 They shared the same heritage. 351 00:23:12,440 --> 00:23:15,520 NARRATOR: So, Naia is an ancestor of modern 352 00:23:15,600 --> 00:23:17,600 Native Americans. 353 00:23:17,680 --> 00:23:22,640 Now, the age of her skeleton, dated to the very end of the Ice Age, 354 00:23:22,720 --> 00:23:25,280 propels her into the center of one of the hottest 355 00:23:25,360 --> 00:23:27,920 controversies in science. 356 00:23:28,000 --> 00:23:32,800 How did she and her people get to the American continent? 357 00:23:33,600 --> 00:23:36,560 JAMES: So, part of the question about Naia was can 358 00:23:36,640 --> 00:23:39,760 she help contribute to an answer to that question? 359 00:23:44,920 --> 00:23:48,800 (waves crashing) 360 00:23:54,040 --> 00:23:57,840 NARRATOR: For decades, experts agreed on how the first humans 361 00:23:57,920 --> 00:24:00,560 migrated to the Americas. 362 00:24:02,640 --> 00:24:06,640 DELGADO: In school, studying archaeology, 363 00:24:06,720 --> 00:24:10,800 I heard a great deal about the Bering Land Bridge. 364 00:24:17,080 --> 00:24:20,280 DELGADO (off-screen): During the last Ice Age, huge ice sheets blocked 365 00:24:20,360 --> 00:24:23,360 the land route from Siberia to Alaska, 366 00:24:23,440 --> 00:24:26,880 but when the ice thaws around 13,000 years ago, 367 00:24:26,960 --> 00:24:30,000 which is when Naia is living in the Yucatán, 368 00:24:30,080 --> 00:24:34,360 it becomes possible for humans to walk into America, 369 00:24:34,440 --> 00:24:36,280 and a group previously known as the 370 00:24:36,360 --> 00:24:39,160 "Clovis people" do just that. 371 00:24:41,040 --> 00:24:43,680 LOREN (off-screen): The Clovis First model is that people came into the 372 00:24:43,760 --> 00:24:47,160 Americas by way of migrating through an ice-free corridor, 373 00:24:47,240 --> 00:24:51,680 exiting south of the ice, hunting megafauna like 374 00:24:51,760 --> 00:24:56,480 mammoths and bison, using a very specific kind 375 00:24:56,560 --> 00:24:59,600 of technology known as a "Clovis spear point." 376 00:25:01,400 --> 00:25:05,160 DELGADO (off-screen): That view that this Clovis group were the people 377 00:25:05,240 --> 00:25:07,240 that had come across the Bering Straits, 378 00:25:07,320 --> 00:25:08,840 and were the ancestors of modern 379 00:25:08,920 --> 00:25:14,080 Native Americans became so fixed in archaeological orthodoxy, 380 00:25:14,160 --> 00:25:17,760 that to suggest an earlier date and other 381 00:25:17,840 --> 00:25:20,600 migrations was scientific heresy. 382 00:25:22,960 --> 00:25:26,360 NARRATOR: The question is, do Naia's people travel 383 00:25:26,440 --> 00:25:30,160 to the Yucatán through the opening ice-free corridor, 384 00:25:30,240 --> 00:25:32,680 or some other way? 385 00:25:36,680 --> 00:25:39,520 LOREN (off-screen): The problem with explaining everything as an 386 00:25:39,600 --> 00:25:42,520 interior migration, that's just not an explanation that 387 00:25:42,600 --> 00:25:45,680 accounts for the facts, and the facts are that people are south 388 00:25:45,760 --> 00:25:48,960 of the ice before this ice-free corridor opens. 389 00:25:50,680 --> 00:25:52,600 The earliest sites, for example, 390 00:25:52,680 --> 00:25:55,040 are actually in South America. 391 00:25:55,120 --> 00:25:58,560 So, there's one in Peru called "Huaca Prieta," 392 00:25:58,640 --> 00:26:01,440 and there's another one in Chile known as "Monte Verde." 393 00:26:03,960 --> 00:26:07,280 Stone tools, bones and charcoal from these sites show 394 00:26:07,360 --> 00:26:09,320 that humans were in the Americas at least 395 00:26:09,400 --> 00:26:11,480 14 and a half thousand years ago, 396 00:26:11,560 --> 00:26:15,320 more than 1,000 years before the ice melts. 397 00:26:17,120 --> 00:26:20,480 NARRATOR: So, if ice is blocking the land route, 398 00:26:20,560 --> 00:26:23,880 how do these earliest Americans arrive? 399 00:26:23,960 --> 00:26:25,680 LOREN (off-screen): They must have come here another way, 400 00:26:25,760 --> 00:26:28,880 so that's why we're interested in looking on the coast, 401 00:26:28,960 --> 00:26:33,120 cause that is the easiest explanation to explain how we 402 00:26:33,200 --> 00:26:35,440 can get people south of the ice before this ice-free 403 00:26:35,520 --> 00:26:36,800 corridor opens up. 404 00:26:38,600 --> 00:26:43,600 NARRATOR: In 1997, scientists begin to uncover evidence of 405 00:26:43,680 --> 00:26:48,920 very early human habitation in this remote valley in Idaho. 406 00:26:49,800 --> 00:26:51,680 LOREN (off-screen): As people were migrating south along the coast, 407 00:26:51,760 --> 00:26:54,200 they would have had ice to their left and the ocean to their right, 408 00:26:54,280 --> 00:26:57,520 and they would have encountered the Columbia River eventually. 409 00:26:58,400 --> 00:27:00,760 They may have decided to just simply take a left-hand turn 410 00:27:00,840 --> 00:27:03,880 south of the ice, and penetrate into North America 411 00:27:03,960 --> 00:27:07,320 at that point, and if they kept going upriver, 412 00:27:07,400 --> 00:27:10,560 they would have made their way here, to Cooper's Ferry. 413 00:27:11,640 --> 00:27:14,760 NARRATOR: Loren and his students search for stone 414 00:27:14,840 --> 00:27:19,320 tools that migrating humans may have left behind. 415 00:27:20,120 --> 00:27:21,520 LOREN (off-screen): Well, if this site was old enough, 416 00:27:21,600 --> 00:27:24,080 we might actually find evidence of Clovis peoples, 417 00:27:24,160 --> 00:27:28,840 but, sorta to my surprise, we didn't see that at all. 418 00:27:29,520 --> 00:27:31,240 LOREN (off-screen): Do you see this thing? 419 00:27:32,440 --> 00:27:36,280 What we did find instead were these other kind of spear points, 420 00:27:36,360 --> 00:27:39,440 and these are known as "stemmed points." 421 00:27:40,600 --> 00:27:44,160 Stemmed points look very different than Clovis points. 422 00:27:44,240 --> 00:27:47,520 LOREN (off-screen): They have a little, small rectangular tab at the bottom. 423 00:27:47,600 --> 00:27:51,600 That just made it very clear that we have some other kind 424 00:27:51,680 --> 00:27:54,800 of cultural pattern that's present at the site, 425 00:27:54,880 --> 00:27:57,240 at the same time people were making Clovis artifacts 426 00:27:57,320 --> 00:27:59,400 somewhere else. 427 00:27:59,480 --> 00:28:02,960 When we first found these, I really didn't have any idea 428 00:28:03,040 --> 00:28:06,720 how old they were, so that was a big question. 429 00:28:07,920 --> 00:28:11,960 Radiocarbon dating showed us that points like these are 430 00:28:12,040 --> 00:28:14,200 13,000 years old. 431 00:28:15,200 --> 00:28:19,200 LOREN (off-screen): Some of them were older, 14,000, 14,500. 432 00:28:20,400 --> 00:28:23,480 And it just blew our minds that this technology could 433 00:28:23,560 --> 00:28:27,000 actually be as old as Clovis, and then even earlier. 434 00:28:28,000 --> 00:28:29,320 NARRATOR: Some challenged this, 435 00:28:29,400 --> 00:28:30,680 but if those dates are correct, 436 00:28:30,760 --> 00:28:33,720 that's 1,000 years before the ice-free corridor, 437 00:28:33,800 --> 00:28:36,640 and at least 2,000 before Naia's time. 438 00:28:36,720 --> 00:28:38,920 How might these people arrive? 439 00:28:39,000 --> 00:28:41,200 Are the stemmed points a clue? 440 00:28:41,280 --> 00:28:42,880 LOREN: The only other place that we find artifacts that 441 00:28:42,960 --> 00:28:45,880 look like this during the end of the last Ice Age are in the 442 00:28:45,960 --> 00:28:48,640 northern part of Japan, on the island of Hokkaido. 443 00:28:50,360 --> 00:28:52,920 NARRATOR: Loren believes this shows how early people 444 00:28:53,000 --> 00:28:56,200 traveled into the Americas from the Far East, 445 00:28:56,280 --> 00:29:00,160 via the Ice Age coastline and rivers. 446 00:29:00,240 --> 00:29:02,480 LOREN (off-screen): If we imagine that people might have been able to 447 00:29:02,560 --> 00:29:05,920 come along the coastline, along the Northern Pacific, 448 00:29:06,000 --> 00:29:09,680 into the Americas, we don't really need to look much farther 449 00:29:09,760 --> 00:29:12,920 than Japan, the Russian Far East, 450 00:29:13,000 --> 00:29:16,440 and they show us that there's a population already in place. 451 00:29:16,520 --> 00:29:19,960 They are on the doorstep, waiting to migrate their way 452 00:29:20,040 --> 00:29:21,840 into the Americas. 453 00:29:23,000 --> 00:29:24,680 DELGADO (off-screen): It didn't mean that you'd have 454 00:29:24,760 --> 00:29:25,920 to sail all the way 455 00:29:26,000 --> 00:29:28,880 across the Pacific or across the Atlantic. 456 00:29:28,960 --> 00:29:33,480 You just island-hopped from bay to bay, making your way, 457 00:29:33,560 --> 00:29:35,160 sometimes over a generation. 458 00:29:36,920 --> 00:29:39,280 LOREN (off-screen): As new sites are being discovered that show us that 459 00:29:39,360 --> 00:29:43,400 people are south of the ice before an ice-free corridor opens, 460 00:29:43,480 --> 00:29:47,200 that requires us to really rethink things. 461 00:29:49,080 --> 00:29:51,440 NARRATOR: To truly understand human migration, 462 00:29:51,520 --> 00:29:54,880 Loren needs to explore the Ice Age coastline. 463 00:29:54,960 --> 00:29:59,760 The problem is, it's now more than 400 feet underwater. 464 00:29:59,840 --> 00:30:01,640 LOREN: How can we find the evidence out there where it 465 00:30:01,720 --> 00:30:03,240 likely exists? 466 00:30:03,320 --> 00:30:04,960 And that takes us offshore, 467 00:30:05,040 --> 00:30:07,240 and we need to look beneath the waves. 468 00:30:15,120 --> 00:30:18,160 LOREN: It's important to understand the coast from an archaeological perspective, 469 00:30:18,240 --> 00:30:19,520 because it could be the place 470 00:30:19,600 --> 00:30:22,320 that holds evidence for the earliest peoples to 471 00:30:22,400 --> 00:30:23,560 come into the Americas. 472 00:30:25,840 --> 00:30:28,560 NARRATOR: Loren Davis is searching for evidence that 473 00:30:28,640 --> 00:30:32,880 early settlers use a coastal route into the Americas, 474 00:30:32,960 --> 00:30:36,280 but he's not looking at today's coastline 475 00:30:36,360 --> 00:30:38,560 for a very good reason. 476 00:30:40,440 --> 00:30:43,440 LOREN (off-screen): During the Ice Age, the coast of the continent 477 00:30:43,520 --> 00:30:46,520 looked very different to how it does now. 478 00:30:46,600 --> 00:30:51,000 When the ice melted, all that trapped water raised sea levels 479 00:30:51,080 --> 00:30:54,280 by over 400 feet, so any evidence of early peoples 480 00:30:54,360 --> 00:30:57,720 living on the coast are now deep underwater. 481 00:30:58,640 --> 00:31:02,320 NARRATOR: And that means searching below the waves, 482 00:31:02,400 --> 00:31:04,960 30 miles out to sea. 483 00:31:06,680 --> 00:31:09,320 LOREN (off-screen): Getting on this ship was a real breakthrough for us, 484 00:31:09,400 --> 00:31:12,840 cause it allowed us to then go out and then ground 485 00:31:12,920 --> 00:31:15,880 truth our theoretical ideas. 486 00:31:16,480 --> 00:31:19,520 WOMAN (over radio): We are off the north east of Heceta Bank, 487 00:31:19,600 --> 00:31:23,240 which is off the central coast of Oregon. 488 00:31:23,960 --> 00:31:27,240 LOREN: We went out to the very edge of the ancient coastline, 489 00:31:27,320 --> 00:31:30,440 so these are areas that are about 130 meters 490 00:31:30,520 --> 00:31:32,480 below modern sea level. 491 00:31:32,560 --> 00:31:33,920 LOREN (over radio): Oh, man! 492 00:31:34,000 --> 00:31:36,400 We went off a cliff! 493 00:31:39,520 --> 00:31:42,080 NARRATOR: Loren one day hopes to find evidence of 494 00:31:42,160 --> 00:31:46,080 prehistoric human settlements on this ancient coastline. 495 00:31:46,160 --> 00:31:50,000 The first step is to build an accurate picture of the hidden 496 00:31:50,080 --> 00:31:53,800 Ice Age landscape below the waves. 497 00:31:54,400 --> 00:31:58,120 LOREN (off-screen): As sea level comes up, it brings a lotta sediment with it, 498 00:31:58,200 --> 00:32:02,040 and it will bury the ancient landscape that was once there, 499 00:32:02,120 --> 00:32:04,560 so this obscures our view. 500 00:32:04,640 --> 00:32:08,480 We really need a technique that allows us to see into the sea floor, 501 00:32:08,560 --> 00:32:12,280 and one of the tools that we use is called a "sub-bottom profiler," 502 00:32:12,360 --> 00:32:14,200 and what this does is it sends a 503 00:32:14,280 --> 00:32:18,920 sound pulse into the sea floor, and it will reflect back an 504 00:32:19,000 --> 00:32:22,000 acoustic signal that it then turns into sort 505 00:32:22,080 --> 00:32:23,480 of a depth map. 506 00:32:24,760 --> 00:32:29,800 MAN (off-screen): Could we track a line bearing 317 at Point Four? 507 00:32:32,240 --> 00:32:35,880 NARRATOR: Merging the deep sea scans with data from computer 508 00:32:35,960 --> 00:32:40,080 models reveals a world not seen for millennia, 509 00:32:40,160 --> 00:32:43,960 the shoreline of Ice Age America. 510 00:32:46,080 --> 00:32:49,520 LOREN: Is we were to lower the ocean down to about 13,000 years ago, 511 00:32:49,600 --> 00:32:50,840 the position where it was then, 512 00:32:50,920 --> 00:32:53,000 we would see a really different coastline. 513 00:32:56,800 --> 00:32:59,240 LOREN (off-screen): We would be able to see river valleys, 514 00:32:59,320 --> 00:33:01,200 we would see embayment's, 515 00:33:01,280 --> 00:33:03,280 we would see a low mountain range. 516 00:33:03,360 --> 00:33:05,800 It would be a broad coastal plain that looks really 517 00:33:05,880 --> 00:33:09,520 different than the rugged, mountainous coastline of 518 00:33:09,600 --> 00:33:11,800 today's central coast. 519 00:33:13,240 --> 00:33:18,880 DELGADO (off-screen): That's a landscape with estuaries full of marine life, 520 00:33:18,960 --> 00:33:21,680 as well as sea birds and animals. 521 00:33:22,680 --> 00:33:27,840 And with that, we would see this lost world, 522 00:33:27,920 --> 00:33:32,480 the Americas as they were at the time of 523 00:33:32,560 --> 00:33:35,040 initial human settlement. 524 00:33:39,920 --> 00:33:42,440 LOREN: This story of ancient coastlines under lower sea 525 00:33:42,520 --> 00:33:45,680 level associated with the last Ice Age is not just an Oregon story. 526 00:33:45,760 --> 00:33:48,120 This is a story that happens everywhere. 527 00:33:49,320 --> 00:33:52,080 NARRATOR: Similar investigations are being conducted 528 00:33:52,160 --> 00:33:55,040 all along the Pacific coast. 529 00:33:57,160 --> 00:33:58,600 LOREN (off-screen): As you go farther south, 530 00:33:58,680 --> 00:34:01,680 San Francisco would have been an area that isn't on the 531 00:34:01,760 --> 00:34:05,000 coast in the past, that it's lowered sea level would have 532 00:34:05,080 --> 00:34:07,920 taken it much farther away from its modern position, 533 00:34:08,000 --> 00:34:09,920 so San Francisco would have been really sort of 534 00:34:10,000 --> 00:34:11,960 an inland valley. 535 00:34:20,800 --> 00:34:25,120 NARRATOR: Having accurate mapping of North America's Ice Age coastline 536 00:34:25,200 --> 00:34:28,600 now allows Loren to narrow his search for signs 537 00:34:28,680 --> 00:34:30,880 of early human habitation. 538 00:34:30,960 --> 00:34:34,080 LOREN (off-screen): So, if I'm a traditional hunter-gatherer or 539 00:34:34,160 --> 00:34:37,840 fisher person, you know, I'm living on an ancient coastline, 540 00:34:37,920 --> 00:34:40,160 where are the hot spots? 541 00:34:40,240 --> 00:34:43,160 Where are the places that are gonna take care of 542 00:34:43,240 --> 00:34:44,720 me the best? 543 00:34:44,800 --> 00:34:47,200 And the estuaries are really, really important 544 00:34:47,280 --> 00:34:48,920 places for people. 545 00:34:49,000 --> 00:34:51,080 I mean, there's more calories per square meter in an estuary 546 00:34:51,160 --> 00:34:53,160 than almost any other place on the coast. 547 00:34:54,280 --> 00:34:57,160 NARRATOR: What really happened remains unclear, 548 00:34:57,240 --> 00:35:00,280 but Loren and others continue to explore, 549 00:35:00,360 --> 00:35:03,400 debate and seek new clues. 550 00:35:03,480 --> 00:35:07,240 LOREN (off-screen): Archaeology works by making discoveries. 551 00:35:08,160 --> 00:35:11,440 In time, my bet is on that these discoveries are going to 552 00:35:11,520 --> 00:35:14,680 be made up and down the Pacific coast of the Americas. 553 00:35:15,360 --> 00:35:17,840 JAMES: This is more anatomical position here. 554 00:35:19,520 --> 00:35:22,400 NARRATOR: When Naia dies, 13,000 years ago, 555 00:35:22,480 --> 00:35:27,840 early humans are arriving in North America via the ice-free corridor, 556 00:35:27,920 --> 00:35:31,360 and the place she is found in the Yucatán is only a 557 00:35:31,440 --> 00:35:34,040 few miles from the Ice Age coastline. 558 00:35:35,520 --> 00:35:38,440 So, which route to Naia's people take? 559 00:35:40,240 --> 00:35:44,720 Jim hopes to find clues in Naia's remains. 560 00:35:44,800 --> 00:35:47,480 JAMES: Here we're looking at a micro-CT scan. 561 00:35:49,920 --> 00:35:51,960 You see one little stress line right there. 562 00:35:52,040 --> 00:35:53,400 See that little line right along, 563 00:35:53,480 --> 00:35:57,280 right near the junction with the dentine? 564 00:35:57,360 --> 00:36:01,360 NARRATOR: He's looking for telltale signs of stress from 565 00:36:01,440 --> 00:36:04,320 her lifestyle and environment. 566 00:36:04,400 --> 00:36:07,320 JAMES: The other place we look is in the long bones 567 00:36:07,400 --> 00:36:08,600 and how they grow. 568 00:36:09,760 --> 00:36:12,600 Here we're looking at Naia's thigh bone, 569 00:36:12,680 --> 00:36:14,920 which is the longest bone and therefore the one that's gonna 570 00:36:15,000 --> 00:36:16,800 give us the most detail. 571 00:36:18,480 --> 00:36:20,200 JAMES (off-screen): See these lines? 572 00:36:20,280 --> 00:36:23,000 These are the places where growth has been interrupted, 573 00:36:23,080 --> 00:36:26,400 and then begun again. 574 00:36:28,920 --> 00:36:31,560 One, two, three, four, five, six. 575 00:36:31,640 --> 00:36:35,000 Two, three, four, five, six years we can see, 576 00:36:35,080 --> 00:36:40,000 and the spacing of those lines in Naia suggest that she had a 577 00:36:40,080 --> 00:36:43,520 protein deficiency during one season of every year. 578 00:36:45,360 --> 00:36:49,160 DOMINIQUE: And so she lived a kind of feast and famine life. 579 00:36:53,600 --> 00:36:56,880 JAMES (off-screen): Seeing that Naia had protein deficiency during some 580 00:36:56,960 --> 00:37:00,400 times of the year raises the question of why was she 581 00:37:00,480 --> 00:37:02,800 protein deficient if she lived so close to the sea? 582 00:37:06,640 --> 00:37:08,760 DOMINIQUE (off-screen): There's fish, there are crustaceans. 583 00:37:08,840 --> 00:37:11,440 The sea is a plentiful place. 584 00:37:12,880 --> 00:37:15,560 JAMES (off-screen): Nothing we're seeing in the evidence for her diet is 585 00:37:15,640 --> 00:37:17,400 consistent with being marine-adapted. 586 00:37:17,480 --> 00:37:20,640 It is quite consistent with being strictly terrestrial. 587 00:37:21,720 --> 00:37:24,840 Her people were not adapted to the coast. 588 00:37:27,200 --> 00:37:30,400 DOMINIQUE: Really what it suggests is that she was among 589 00:37:30,480 --> 00:37:33,280 these highly mobile hunter-gatherers who were 590 00:37:33,360 --> 00:37:36,160 heavily reliant on a successful hunt, 591 00:37:36,240 --> 00:37:41,120 their ability to hunt and to kill and to consume megafauna. 592 00:37:41,200 --> 00:37:44,240 DOMINIQUE (off-screen): And the fact that she appears unable to fish or make use of 593 00:37:44,320 --> 00:37:47,360 marine proteins, that really doesn't make sense if her 594 00:37:47,440 --> 00:37:49,120 people had traveled to the Americas 595 00:37:49,200 --> 00:37:51,280 via a coastal highway. 596 00:37:52,560 --> 00:37:55,520 DELGADO: The most dangerous thing in science is to be 597 00:37:55,600 --> 00:37:58,400 disappointed when the evidence doesn't support your theory, 598 00:37:58,480 --> 00:38:01,400 so when Naia was found, given her age, it was, like, 599 00:38:01,480 --> 00:38:03,120 "Wow! She had to be a coastal person." 600 00:38:03,200 --> 00:38:05,160 Well, that doesn't show up in her bones. 601 00:38:07,040 --> 00:38:10,400 JAMES (off-screen): While she doesn't disprove the coastal migration theory, 602 00:38:10,480 --> 00:38:12,440 she certainly does not support it. 603 00:38:13,800 --> 00:38:16,600 NARRATOR: But that doesn't rule out others coming via the 604 00:38:16,680 --> 00:38:21,600 coastal route at least 2,000 years before her time. 605 00:38:22,480 --> 00:38:24,760 DELGADO (off-screen): It's just the most fascinating puzzle. 606 00:38:24,840 --> 00:38:28,480 I think it's likely that there were multiple migrations, 607 00:38:28,560 --> 00:38:32,080 following different routes, over thousands of years. 608 00:38:32,160 --> 00:38:35,160 NARRATOR: As for Naia, we are still finding out 609 00:38:35,240 --> 00:38:39,000 more about her life and death. 610 00:38:39,080 --> 00:38:42,000 JAMES (off-screen): The hardest ones to work with are the young people. 611 00:38:42,080 --> 00:38:44,040 You think about a life not lived, 612 00:38:44,120 --> 00:38:47,920 but you also think about the impact of the loss of that individual 613 00:38:48,000 --> 00:38:51,440 on their parents, their siblings, 614 00:38:51,520 --> 00:38:53,640 their, their young spouses. 615 00:38:53,720 --> 00:38:56,400 NARRATOR: Now they want to piece together the clues to 616 00:38:56,480 --> 00:38:59,440 understand what may have happened to Naia in the 617 00:38:59,520 --> 00:39:03,480 Yucatán cave system, 13,000 years ago. 618 00:39:13,560 --> 00:39:16,680 JAMES (off-screen): When we're working with ancient human skeletons, 619 00:39:16,760 --> 00:39:18,840 we're dealing with the ultimate cold cases. 620 00:39:20,200 --> 00:39:23,640 NARRATOR: Jim Chatters' forensic examinations reveal 621 00:39:23,720 --> 00:39:27,640 an injury from which Naia would not have recovered. 622 00:39:28,680 --> 00:39:31,600 JAMES (off-screen): We know from her pelvis, 623 00:39:31,680 --> 00:39:35,000 she struck the front of her pelvis here, 624 00:39:35,080 --> 00:39:37,680 and it broke away the pubic bones on both sides. 625 00:39:37,760 --> 00:39:40,280 JAMES (off-screen): These jagged, jagged breaks that you see here 626 00:39:40,360 --> 00:39:41,920 are green bone fractures. 627 00:39:42,000 --> 00:39:44,720 They're the kinda breaks that fresh bone gets, not old, 628 00:39:44,800 --> 00:39:46,080 dead bone gets. 629 00:39:46,160 --> 00:39:47,760 This was a serious accident. 630 00:39:47,840 --> 00:39:49,520 It is not easy to break your pelvis, 631 00:39:49,600 --> 00:39:52,280 not to shatter it like that. 632 00:39:54,120 --> 00:39:58,200 NARRATOR: To determine would could have caused Naia's fatal injury, 633 00:39:58,280 --> 00:40:01,880 Dominique Rissolo and Jim attempt to retrace her 634 00:40:01,960 --> 00:40:05,880 footsteps in the 3D replica of the cave. 635 00:40:05,960 --> 00:40:08,520 DOMINIQUE: It's impossible not to wonder why Naia 636 00:40:08,600 --> 00:40:09,640 was in the cave. 637 00:40:11,680 --> 00:40:14,600 JAMES (off-screen): Hoyo Negro had a pool of water in the bottom. 638 00:40:14,680 --> 00:40:17,360 Was she there for water? 639 00:40:19,400 --> 00:40:23,240 DOMINIQUE: This would have been the route that she would have walked. 640 00:40:23,320 --> 00:40:25,080 JAMES: This is the most likely way she came in. 641 00:40:25,160 --> 00:40:28,440 The closest entrance is about 2,000 feet behind us. 642 00:40:29,800 --> 00:40:34,440 (Naia breathing heavily) 643 00:40:36,880 --> 00:40:40,800 Imagine she is deep in the cave and she's lost her way, 644 00:40:40,880 --> 00:40:43,000 which would have been easy in these caverns. 645 00:40:44,800 --> 00:40:47,400 These tunnels, they join and they separate, 646 00:40:47,480 --> 00:40:50,240 and join and separate, and getting lost would be 647 00:40:50,320 --> 00:40:51,480 a very easy thing to do. 648 00:40:55,080 --> 00:40:56,880 You can turn to the left, 649 00:40:56,960 --> 00:40:59,720 and work your way over some boulders. 650 00:41:01,200 --> 00:41:04,360 DOMINIQUE: Was she being pursued by another animal 651 00:41:04,440 --> 00:41:05,640 inside the cave? 652 00:41:07,400 --> 00:41:10,120 JAMES (off-screen): She knows there are large, dangerous animals there. 653 00:41:16,240 --> 00:41:18,800 DOMINIQUE: So, kinda climbing over these rocks and close to the edge. 654 00:41:18,880 --> 00:41:20,400 JAMES: Yeah. 655 00:41:20,480 --> 00:41:22,600 DOMINIQUE: You know, maybe trying to find a way around 656 00:41:22,680 --> 00:41:24,480 the pit? 657 00:41:24,560 --> 00:41:27,720 JAMES (off-screen): Otherwise we can't get her over to where she fell. 658 00:41:29,360 --> 00:41:31,200 Eventually her light's gonna go out 659 00:41:31,280 --> 00:41:32,840 and she's wandering in the dark. 660 00:41:33,440 --> 00:41:35,280 (Naia breathing heavily) 661 00:41:35,360 --> 00:41:38,160 JAMES (off-screen): And suddenly she takes one final step, 662 00:41:38,240 --> 00:41:40,640 and the bottom falls away. 663 00:41:41,680 --> 00:41:43,120 Whoa! 664 00:41:47,600 --> 00:41:50,680 From the floor of that tunnel to the surface of the water 665 00:41:50,760 --> 00:41:56,160 below was right about 100 feet, 30 meters. 666 00:41:56,240 --> 00:41:57,600 JAMES (off-screen): And if you look straight down the rim here. 667 00:41:57,680 --> 00:41:58,880 DOMINIQUE (off-screen): Yeah, that's the rim, yeah. 668 00:41:58,960 --> 00:42:00,160 Yeah, yeah, yeah. 669 00:42:00,240 --> 00:42:01,360 JAMES (off-screen): She's right down there. 670 00:42:01,440 --> 00:42:03,080 DOMINIQUE (off-screen): Oh my goodness! 671 00:42:03,160 --> 00:42:04,120 JAMES: So you fall. Okay, now, Joel, just swing straight down. 672 00:42:05,120 --> 00:42:07,600 From where her body was, it looks like she probably went through the water 673 00:42:07,680 --> 00:42:09,560 and smacked the rocks down below it. 674 00:42:10,720 --> 00:42:13,200 JAMES (off-screen): I imagine she was knocked unconscious and didn't know a 675 00:42:13,280 --> 00:42:15,000 thing after that. 676 00:42:17,120 --> 00:42:19,520 NARRATOR: What happens next sets in motion an 677 00:42:19,600 --> 00:42:21,880 extraordinary series of events, 678 00:42:21,960 --> 00:42:27,640 which preserved Naia's remains for the next 13,000 years. 679 00:42:28,880 --> 00:42:31,080 DOMINIQUE (off-screen): And what we see, of course, 680 00:42:31,160 --> 00:42:35,040 is global sea level rise, and those rising sea levels 681 00:42:35,120 --> 00:42:38,720 are pushing the fresh water that lies under the Peninsula up. 682 00:42:39,840 --> 00:42:42,080 And this chamber is flooding, 683 00:42:42,160 --> 00:42:44,000 and it's flooding surprisingly fast. 684 00:42:44,080 --> 00:42:48,280 Over a few thousand years we see a, a dry cave, 685 00:42:48,360 --> 00:42:50,640 to a completely flooded one. 686 00:42:50,720 --> 00:42:54,160 It's a really rapid and incredible transformation. 687 00:42:56,200 --> 00:42:58,800 JAMES (off-screen): That sealed the cave off, 688 00:42:59,920 --> 00:43:02,680 and it became absolutely isolated from the 689 00:43:02,760 --> 00:43:03,920 rest of the world. 690 00:43:05,800 --> 00:43:10,120 JAMES (off-screen): It wasn't until cave divers, just exploring for the sheer 691 00:43:10,200 --> 00:43:14,200 joy of it, happened upon this huge black hole. 692 00:43:16,880 --> 00:43:21,120 NARRATOR: For Dominique and the team of scientists studying her, 693 00:43:21,200 --> 00:43:24,360 Naia's story is not yet complete. 694 00:43:24,440 --> 00:43:29,200 JAMES (off-screen): She comes to us forward in time as a messenger, 695 00:43:29,280 --> 00:43:33,640 and tells us of the life of people lost so long ago. 696 00:43:37,080 --> 00:43:39,160 DOMINIQUE (off-screen): We know very little about her culture. 697 00:43:39,240 --> 00:43:41,440 We certainly don't know what language she spoke. 698 00:43:41,520 --> 00:43:45,000 We don't have stone tools, we don't have artifacts. 699 00:43:45,080 --> 00:43:47,680 DOMINIQUE (off-screen): Those have yet to be discovered. 700 00:43:49,360 --> 00:43:52,320 LOREN (off-screen): One of these days I hope that we actually find 701 00:43:52,400 --> 00:43:55,520 artifacts that are a very clear human origin. 702 00:43:55,600 --> 00:43:58,880 I hope that we find information about the foods 703 00:43:58,960 --> 00:44:00,440 that they're eating. 704 00:44:00,520 --> 00:44:02,520 We may even get as lucky as to find something that reflects 705 00:44:02,600 --> 00:44:04,920 the personal life of somebody. 706 00:44:05,000 --> 00:44:07,440 LOREN (off-screen): To me, it's only a matter of time. 707 00:44:07,520 --> 00:44:08,680 Captioned by Cotter Media Group.