1 00:00:01,166 --> 00:00:03,200 ♪ ♪ 2 00:00:06,200 --> 00:00:08,833 NARRATOR: In the sands of the Egyptian Desert, 3 00:00:08,833 --> 00:00:13,933 experts are uncovering clues to a lost past. 4 00:00:13,933 --> 00:00:17,166 Look at this! Right here. 5 00:00:17,166 --> 00:00:21,433 NARRATOR: From a time long before the pharaohs, 6 00:00:21,433 --> 00:00:24,833 when this place was underwater 7 00:00:24,833 --> 00:00:27,400 and whales... 8 00:00:27,400 --> 00:00:29,466 Had legs? 9 00:00:29,466 --> 00:00:31,533 HESHAM SALLAM: Here's the hind limb 10 00:00:31,533 --> 00:00:33,100 of this beast. 11 00:00:33,100 --> 00:00:35,533 It's just like T. rex hand, 12 00:00:35,533 --> 00:00:37,133 do nothing. 13 00:00:37,133 --> 00:00:38,700 ♪ ♪ 14 00:00:38,700 --> 00:00:41,966 NARRATOR: Whales are the world's biggest mammals. 15 00:00:41,966 --> 00:00:45,366 But how did they end up in the ocean? 16 00:00:45,366 --> 00:00:46,600 This is so awesome. 17 00:00:48,066 --> 00:00:49,533 They're doing everything mammals do, 18 00:00:49,533 --> 00:00:50,800 but in the water. 19 00:00:50,800 --> 00:00:54,166 ♪ ♪ 20 00:00:54,166 --> 00:00:57,666 NARRATOR: Now new discoveries are revealing clues 21 00:00:57,666 --> 00:01:00,933 about their evolutionary past. 22 00:01:00,933 --> 00:01:02,866 Wow! Look at this! 23 00:01:02,866 --> 00:01:05,366 SALLAM: Oh, my word! 24 00:01:05,366 --> 00:01:08,466 PHILIP GINGERICH: When I first saw it, I had no idea what it was. 25 00:01:08,466 --> 00:01:10,500 NARRATOR: From prehistoric predators 26 00:01:10,500 --> 00:01:15,633 to the largest animal that has ever lived. 27 00:01:15,633 --> 00:01:19,733 How did the whale's journey begin? 28 00:01:19,733 --> 00:01:24,600 It's one of the greatest stories of evolution. 29 00:01:24,600 --> 00:01:27,000 "When Whales Could Walk." 30 00:01:27,000 --> 00:01:30,533 Right now, on "NOVA." 31 00:01:30,533 --> 00:01:35,233 ♪ ♪ 32 00:01:51,700 --> 00:01:56,733 ♪ ♪ 33 00:01:58,466 --> 00:02:01,700 NARRATOR: Wadi Hitan, in Egypt's Sahara Desert. 34 00:02:03,766 --> 00:02:06,866 Hidden beneath these rocks are secrets 35 00:02:06,866 --> 00:02:09,533 from a time long before humans. 36 00:02:09,533 --> 00:02:14,866 ♪ ♪ 37 00:02:23,200 --> 00:02:26,633 SALLAM: Many people think of Egypt like 38 00:02:26,633 --> 00:02:29,566 ancient Egyptian civilization. 39 00:02:29,566 --> 00:02:33,133 Like pharaohs, Sphinx, and Romans, even. 40 00:02:33,133 --> 00:02:37,833   But what I'm studying is way beyond this time. 41 00:02:37,833 --> 00:02:39,666 Prehistoric life. 42 00:02:39,666 --> 00:02:43,533 NARRATOR: Paleontologist Hesham Sallam 43 00:02:43,533 --> 00:02:48,300 is on a mission to uncover his country's prehistoric past. 44 00:02:48,300 --> 00:02:51,600 SALLAM: The place that we are heading toward 45 00:02:51,600 --> 00:02:54,333 is one of the most important 46 00:02:54,333 --> 00:02:58,966 place in Egypt, if not in the world, 47 00:02:58,966 --> 00:03:01,700 in term of paleontology. 48 00:03:07,666 --> 00:03:09,733 NARRATOR: Hesham is searching for clues 49 00:03:09,733 --> 00:03:12,866 to an extraordinary evolutionary mystery. 50 00:03:12,866 --> 00:03:15,133 ♪ ♪ 51 00:03:15,133 --> 00:03:17,100 Here, it's the middle of nowhere, 52 00:03:17,100 --> 00:03:19,000 it seems like empty place, 53 00:03:19,000 --> 00:03:23,300 but there is tons of evidence that you can see. 54 00:03:23,300 --> 00:03:25,200 Fossils are everywhere, 55 00:03:25,200 --> 00:03:27,466 telling you what life looked like 56 00:03:27,466 --> 00:03:29,766 40 million years ago. 57 00:03:29,766 --> 00:03:33,666 NARRATOR: Across more than 75 square miles, 58 00:03:33,666 --> 00:03:37,433 fossils litter the desert. 59 00:03:37,433 --> 00:03:40,100 There are so many, 60 00:03:40,100 --> 00:03:44,200 Hesham has to remove his shoes to avoid crushing them. 61 00:03:44,200 --> 00:03:47,533 Just look at this, for example. 62 00:03:47,533 --> 00:03:51,900 There's a really nice shell. 63 00:03:51,900 --> 00:03:55,566 Really wonderful, well-preserved. 64 00:03:55,566 --> 00:03:59,000 It's look like living one, 65 00:03:59,000 --> 00:04:01,933 but it was living 66 00:04:01,933 --> 00:04:03,700 40 million years ago. 67 00:04:03,700 --> 00:04:05,733 ♪ ♪ 68 00:04:05,733 --> 00:04:10,433 NARRATOR: But this desert also hides much larger fossils. 69 00:04:10,433 --> 00:04:13,100 SALLAM: This is typically what you see in Wadi Hitan: 70 00:04:13,100 --> 00:04:16,033 the bone sticking out from the cliff, 71 00:04:16,033 --> 00:04:19,700 calling you to come and see it. 72 00:04:19,700 --> 00:04:24,666 And indeed, this is a really huge animal. 73 00:04:24,666 --> 00:04:28,066 The vertebra would be that big. 74 00:04:28,066 --> 00:04:30,700 And not only the vertebrae, 75 00:04:30,700 --> 00:04:33,800 but also, you can find ribs all over the place. 76 00:04:33,800 --> 00:04:37,300 Given the size of the vertebrae, 77 00:04:37,300 --> 00:04:41,466 it might be getting up to 20 meter long. 78 00:04:42,666 --> 00:04:46,066 NARRATOR: The size and shape of an animal around 60 feet long 79 00:04:46,066 --> 00:04:48,433 encased in this rock 80 00:04:48,433 --> 00:04:52,900 has led scientists to a remarkable conclusion. 81 00:04:52,900 --> 00:04:56,366 SALLAM: I think we have a complete skeleton 82 00:04:56,366 --> 00:04:59,233 of the prehistoric whale that lived here in Egypt, 83 00:04:59,233 --> 00:05:01,766 long, long, long time ago. 84 00:05:01,766 --> 00:05:04,133 ♪ ♪ 85 00:05:04,133 --> 00:05:08,533 NARRATOR: Since the first whale fossils were discovered here in 1902, 86 00:05:08,533 --> 00:05:12,500 experts have found around 1,000 individuals. 87 00:05:15,166 --> 00:05:20,166 This is the biggest ancient whale graveyard known on Earth. 88 00:05:20,166 --> 00:05:24,533 That's why paleontologists named it Wadi Hitan-- 89 00:05:24,533 --> 00:05:27,800 the Valley of the Whales. 90 00:05:29,400 --> 00:05:31,800 But what are these sea creatures doing here 91 00:05:31,800 --> 00:05:36,766 in a desert over 100 miles from the coast? 92 00:05:36,766 --> 00:05:41,300 ♪ ♪ 93 00:05:41,300 --> 00:05:43,666 Shorouq Al-Ashqar is one of Egypt's 94 00:05:43,666 --> 00:05:46,133 first female vertebrate paleontologists. 95 00:05:49,433 --> 00:05:52,400 AL-ASHQAR: These are shark teeth. 96 00:05:52,400 --> 00:05:56,500 Also, look at these shells. 97 00:05:56,500 --> 00:06:00,300 These animals live at the bottom of the sea. 98 00:06:01,800 --> 00:06:06,133 NARRATOR: Nearby, Shorouq finds another clue. 99 00:06:06,133 --> 00:06:08,433 AL-ASHQAR: Look at this structure. 100 00:06:08,433 --> 00:06:11,166 Many scientists do believe that these 101 00:06:11,166 --> 00:06:13,766 are mangrove roots, as they found 102 00:06:13,766 --> 00:06:17,500 a lot of mangrove seeds all over the area. 103 00:06:17,500 --> 00:06:19,833 But other scientists 104 00:06:19,833 --> 00:06:23,866 believe that these might be crustacean burrows. 105 00:06:23,866 --> 00:06:25,800 Crabs, snails 106 00:06:25,800 --> 00:06:29,666 lived there and burrowed in the soft sand. 107 00:06:31,866 --> 00:06:34,566 NARRATOR: Whether these are fossilized mangrove roots 108 00:06:34,566 --> 00:06:37,700 or burrows dug by prehistoric crustaceans, 109 00:06:37,700 --> 00:06:40,500 it's clear 110 00:06:40,500 --> 00:06:44,300 this area was once underwater. 111 00:06:44,300 --> 00:06:46,600 ♪ ♪ 112 00:06:46,600 --> 00:06:49,633 Today's excavation site was at the bottom of the sea 113 00:06:49,633 --> 00:06:52,900 40 million years ago. 114 00:06:52,900 --> 00:06:55,433 Back then, the Mediterranean was part 115 00:06:55,433 --> 00:06:59,800 of a much larger ocean, the Tethys. 116 00:06:59,800 --> 00:07:02,600 It stretched from Europe to India, 117 00:07:02,600 --> 00:07:05,600 and was full of marine life. 118 00:07:05,600 --> 00:07:08,000 ♪ ♪ 119 00:07:08,000 --> 00:07:10,133 But when sea levels dropped, 120 00:07:10,133 --> 00:07:14,233 they left behind a seabed rich in fossils. 121 00:07:15,900 --> 00:07:19,833 Today, this desert is the resting place of some 122 00:07:19,833 --> 00:07:23,800 of the earliest whales ever found. 123 00:07:23,800 --> 00:07:28,700 They may hold the key to how today's ocean giants evolved. 124 00:07:30,133 --> 00:07:35,466 ♪ ♪ 125 00:07:35,466 --> 00:07:38,933 6,000 miles away, in the Dominican Republic, 126 00:07:38,933 --> 00:07:42,600 living whales gather in these tropical waters 127 00:07:42,600 --> 00:07:44,666 early in the year. 128 00:07:44,666 --> 00:07:49,133 ♪ ♪ 129 00:07:51,166 --> 00:07:55,133 It's humpback whale breeding season. 130 00:07:55,133 --> 00:07:58,566 Comparative anatomist Joy Reidenberg 131 00:07:58,566 --> 00:08:01,766 has come to study them. 132 00:08:01,766 --> 00:08:03,600 REIDENBERG: Oh, there's a blow. 133 00:08:03,600 --> 00:08:05,300 Wow-- oh, and just the other side! 134 00:08:05,300 --> 00:08:06,666 Did you see that? 135 00:08:06,666 --> 00:08:08,733 There's this tiny little fin-- that's the baby! 136 00:08:08,733 --> 00:08:11,233 We've got a mother and her calf right here together, 137 00:08:11,233 --> 00:08:12,333 swimming side by side. 138 00:08:14,600 --> 00:08:17,733 NARRATOR: Humpbacks are one of around 90 different species 139 00:08:17,733 --> 00:08:19,433 of whale living today 140 00:08:19,433 --> 00:08:22,366 that include toothed whales, 141 00:08:22,366 --> 00:08:24,933 like orcas, dolphins, and porpoises, 142 00:08:24,933 --> 00:08:28,233 and baleen whales, like these humpbacks. 143 00:08:28,233 --> 00:08:33,466 Whales can swim thousands of miles, 144 00:08:33,466 --> 00:08:34,600 dive thousands of feet, 145 00:08:34,600 --> 00:08:38,466 and stay underwater for over an hour. 146 00:08:38,466 --> 00:08:41,100 ♪ ♪ 147 00:08:41,100 --> 00:08:43,166 REIDENBERG: I love whales, I really do. 148 00:08:43,166 --> 00:08:46,200 Such magnificent, huge creatures. 149 00:08:46,200 --> 00:08:49,700 And so well-adapted for being in the water. 150 00:08:49,700 --> 00:08:52,666 ♪ ♪ 151 00:08:52,666 --> 00:08:54,733 NARRATOR: And yet, they're mammals. 152 00:08:54,733 --> 00:08:57,833 They breathe air using lungs. 153 00:08:57,833 --> 00:09:00,000 Just like us. 154 00:09:00,000 --> 00:09:03,400 ♪ ♪ 155 00:09:04,800 --> 00:09:06,566 REIDENBERG: We've got a mother and calf over here. 156 00:09:06,566 --> 00:09:08,500 The mother is nursing its baby. 157 00:09:08,500 --> 00:09:11,766 But these animals not only breathe air and give milk, 158 00:09:11,766 --> 00:09:14,566 but they're doing everything mammals do, but in the water. 159 00:09:14,566 --> 00:09:16,300 They have to mate in the water. 160 00:09:16,300 --> 00:09:18,533 They have to carry their pregnancy in the water. 161 00:09:18,533 --> 00:09:20,133 They have to find food in the water. 162 00:09:20,133 --> 00:09:21,766 And then they give birth in the water. 163 00:09:21,766 --> 00:09:22,900 All of this 164 00:09:22,900 --> 00:09:25,133 because these animals have evolved 165 00:09:25,133 --> 00:09:26,900 to be an aquatic mammal. 166 00:09:26,900 --> 00:09:28,666 ♪ ♪ 167 00:09:28,666 --> 00:09:33,200 NARRATOR: How did air-breathing mammals end up in the ocean? 168 00:09:33,200 --> 00:09:34,633 ♪ ♪ 169 00:09:34,633 --> 00:09:38,900 For centuries, many people confused whales with fish, 170 00:09:38,900 --> 00:09:43,100 including the characters in the novel "Moby-Dick." 171 00:09:43,100 --> 00:09:46,200 ♪ ♪ 172 00:09:46,200 --> 00:09:48,533 Even though, in the 1750s, 173 00:09:48,533 --> 00:09:51,533 the Swedish naturalist Carl Linnaeus 174 00:09:51,533 --> 00:09:54,533 had already classified whales as mammals, 175 00:09:54,533 --> 00:09:57,300 recognizing that, among other traits, 176 00:09:57,300 --> 00:10:00,666 they have lungs and produce milk. 177 00:10:00,666 --> 00:10:03,766 But where whales came from caused even 178 00:10:03,766 --> 00:10:05,966 Charles Darwin to scratch his beard. 179 00:10:05,966 --> 00:10:08,766 Inspired by a bear seen feeding while it swam, 180 00:10:08,766 --> 00:10:13,366 he imagined how whales could evolve from land mammals. 181 00:10:13,366 --> 00:10:15,033 But faced with ridicule, 182 00:10:15,033 --> 00:10:18,166 he removed this idea from his later writings. 183 00:10:18,166 --> 00:10:21,166 ♪ ♪ 184 00:10:21,166 --> 00:10:24,833 Perhaps Darwin's hunch had legs. 185 00:10:24,833 --> 00:10:29,400 Could it be that whales hadn't evolved in the water, 186 00:10:29,400 --> 00:10:31,733 but were actually descended from mammals 187 00:10:31,733 --> 00:10:34,900 that once walked on land? 188 00:10:34,900 --> 00:10:41,233 It almost seems like evolution had taken a backwards step. 189 00:10:42,866 --> 00:10:46,300 ♪ ♪ 190 00:10:46,300 --> 00:10:49,300 It's a question that fascinates Hesham Sallam. 191 00:10:49,300 --> 00:10:52,166 He believes clues can be found 192 00:10:52,166 --> 00:10:56,200 in the huge fossils that lie scattered in this desert. 193 00:11:00,500 --> 00:11:04,133 This is one of the most complete skeleton 194 00:11:04,133 --> 00:11:06,533 that we find in Wadi Hitan. 195 00:11:06,533 --> 00:11:08,733 In the middle of nowhere, 196 00:11:08,733 --> 00:11:14,366 you find a lot of really huge vertebrae lined up. 197 00:11:14,366 --> 00:11:18,333 The skull would be over there in that rock, 198 00:11:18,333 --> 00:11:21,466 and the ribs on both side. 199 00:11:21,466 --> 00:11:24,633 This is really spectacularly huge animal 200 00:11:24,633 --> 00:11:28,733 that lived here in Wadi Hitan 40 million years ago, 201 00:11:28,733 --> 00:11:30,466 the Basilosaurus. 202 00:11:30,466 --> 00:11:32,500 ♪ ♪ 203 00:11:32,500 --> 00:11:35,366 NARRATOR: Basilosaurus fossils have been discovered 204 00:11:35,366 --> 00:11:37,266 in many parts of the world, 205 00:11:37,266 --> 00:11:41,666 including around 600 here at Wadi Hitan. 206 00:11:42,966 --> 00:11:46,800 This one has been laid out in the place it was found. 207 00:11:48,700 --> 00:11:52,966 When the first Basilosaurus was studied in 1834, 208 00:11:52,966 --> 00:11:55,333 experts were baffled. 209 00:11:55,333 --> 00:11:57,700 SALLAM: When the early scientists found this, 210 00:11:57,700 --> 00:11:59,366 they thought it's belonged 211 00:11:59,366 --> 00:12:03,200 to a kind of gigantic marine reptile. 212 00:12:03,200 --> 00:12:08,066 And the, this is why they give it name "Basilosaurus," 213 00:12:08,066 --> 00:12:10,366 which means "king lizard." 214 00:12:10,366 --> 00:12:12,800 ♪ ♪ 215 00:12:12,800 --> 00:12:15,166 NARRATOR: But the skull contains a clue 216 00:12:15,166 --> 00:12:19,766 to Basilosaurus's true identity. 217 00:12:19,766 --> 00:12:21,966 This is the skull upside down, and you can see 218 00:12:21,966 --> 00:12:23,633 all the teeth are sticking up. 219 00:12:23,633 --> 00:12:25,566 And this, actually, 220 00:12:25,566 --> 00:12:27,733 they have incisors, canine, 221 00:12:27,733 --> 00:12:29,933 premolars, and molar. 222 00:12:29,933 --> 00:12:32,066 Really, like our teeth, 223 00:12:32,066 --> 00:12:36,266 which is actually a really good indication for, 224 00:12:36,266 --> 00:12:40,833 this is not a marine reptile, this is actually mammal. 225 00:12:40,833 --> 00:12:43,733 So Basilosaurus, the king lizard, 226 00:12:43,733 --> 00:12:47,800 it's actually ancient whale. 227 00:12:47,800 --> 00:12:51,600 ♪ ♪ 228 00:12:51,600 --> 00:12:53,266 NARRATOR: 40 million years ago, 229 00:12:53,266 --> 00:12:59,133 Basilosaurus was the apex predator of its day. 230 00:12:59,133 --> 00:13:01,900 It could grow up to 60 feet long, 231 00:13:01,900 --> 00:13:04,566 the length of a bowling alley, 232 00:13:04,566 --> 00:13:07,433 and weigh more than seven tons. 233 00:13:09,700 --> 00:13:14,000 Powerful jaws filled with sharp teeth made it 234 00:13:14,000 --> 00:13:15,833 a killing machine. 235 00:13:15,833 --> 00:13:21,366 Scientists estimate its bite had a force of nearly two tons, 236 00:13:21,366 --> 00:13:25,333 enough to crush the bones of other whales. 237 00:13:25,333 --> 00:13:29,966 Basilosaurus was a prehistoric king of beasts. 238 00:13:33,766 --> 00:13:36,866 But its discovery didn't initially shed much light 239 00:13:36,866 --> 00:13:38,966 on whale evolution. 240 00:13:38,966 --> 00:13:42,566 Or how these mammals ended up in the ocean. 241 00:13:48,066 --> 00:13:50,966 It's a mystery that has intrigued Philip Gingerich 242 00:13:50,966 --> 00:13:53,766 for almost 50 years. 243 00:13:53,766 --> 00:13:57,333 A pioneer in the field of whale evolution, 244 00:13:57,333 --> 00:13:59,266 he was one of the first paleontologists 245 00:13:59,266 --> 00:14:03,966 to excavate at Wadi Hitan. 246 00:14:03,966 --> 00:14:07,566 So this is where I keep the fossils I'm working on. 247 00:14:07,566 --> 00:14:11,233 So here is the skull of Basilosaurus. 248 00:14:11,233 --> 00:14:13,600 Uh, it's upside down. 249 00:14:13,600 --> 00:14:16,733 And this is a model of it, a cast of it. 250 00:14:16,733 --> 00:14:18,966   These are all from Egypt, from Wadi Hitan. 251 00:14:18,966 --> 00:14:21,900 Collected in 2005. 252 00:14:21,900 --> 00:14:24,100 Here we are, I'm still working on them. 253 00:14:24,100 --> 00:14:25,800 (chuckling): Takes time. 254 00:14:27,000 --> 00:14:31,300 NARRATOR: When Philip started his career, he studied land mammals. 255 00:14:31,300 --> 00:14:35,200 At the time, paleontologists had very little idea 256 00:14:35,200 --> 00:14:37,866 about the origins of whales. 257 00:14:37,866 --> 00:14:43,500 I grew up in the Midwest and I wasn't near the ocean, and... 258 00:14:43,500 --> 00:14:45,633 I didn't know anything about whales. 259 00:14:45,633 --> 00:14:48,266 I knew so little that I wasn't interested. 260 00:14:48,266 --> 00:14:49,900 ♪ ♪ 261 00:14:49,900 --> 00:14:53,166 NARRATOR: In 1978, Philip went to Pakistan 262 00:14:53,166 --> 00:14:55,233 to search for prehistoric horses. 263 00:14:56,800 --> 00:14:59,833 Instead, his team unearthed the remains 264 00:14:59,833 --> 00:15:03,333 of a mysterious creature. 265 00:15:03,333 --> 00:15:06,566 The first thing we found was this skull. 266 00:15:06,566 --> 00:15:09,400 Back of a skull-- it's not complete. 267 00:15:09,400 --> 00:15:11,866 The front, the part with the eyes 268 00:15:11,866 --> 00:15:14,000 and the teeth and everything, has broken off. 269 00:15:14,000 --> 00:15:17,600 When I first saw it, I had no idea what it was. 270 00:15:17,600 --> 00:15:19,400 I was probably disappointed, because 271 00:15:19,400 --> 00:15:22,500 I was looking for horses, and it clearly wasn't a horse. 272 00:15:22,500 --> 00:15:26,366 But what it was, I couldn't figure out. 273 00:15:27,566 --> 00:15:31,366 NARRATOR: The team named the strange animal Pakicetus. 274 00:15:31,366 --> 00:15:34,933 It's about 50 million years old. 275 00:15:34,933 --> 00:15:39,100 When Philip took a closer look, he spotted something 276 00:15:39,100 --> 00:15:42,400 unexpected in the creature's ear. 277 00:15:42,400 --> 00:15:44,600 So when you look at this covering bone, 278 00:15:44,600 --> 00:15:46,166 covering the ear, 279 00:15:46,166 --> 00:15:50,800 it's very dense, it's thickened, 280 00:15:50,800 --> 00:15:54,133 it has a sloping surface on this side. 281 00:15:54,133 --> 00:15:57,233 And in modern mammals, those are only found in whales. 282 00:15:57,233 --> 00:16:00,900 And why? To enable them to hear in water. 283 00:16:00,900 --> 00:16:02,433 ♪ ♪ 284 00:16:02,433 --> 00:16:05,433 NARRATOR: This ear bone, unique to whales and dolphins, 285 00:16:05,433 --> 00:16:09,533 helps them locate the direction of sounds underwater. 286 00:16:09,533 --> 00:16:13,066 It's proof of Pakicetus's pedigree. 287 00:16:13,066 --> 00:16:16,033 GINGERICH: This bone was the key to understanding 288 00:16:16,033 --> 00:16:18,400 that Pakicetus is a whale. 289 00:16:18,400 --> 00:16:22,166 That made it the oldest fossil whale anybody ever found. 290 00:16:22,166 --> 00:16:25,333 NARRATOR: It was groundbreaking. 291 00:16:25,333 --> 00:16:29,533 And as they discover more Pakicetus fossils, 292 00:16:29,533 --> 00:16:33,433 they realized something else. 293 00:16:33,433 --> 00:16:38,166 This whale could walk. 294 00:16:38,166 --> 00:16:42,066 Pakicetus is an animal a little bigger than a wolf. 295 00:16:42,066 --> 00:16:45,900 Probably built approximately like a wolf. 296 00:16:45,900 --> 00:16:49,433 It has teeth like a carnivorous mammal. 297 00:16:49,433 --> 00:16:54,466 NARRATOR: But unlike a wolf, that has claws on the ends of its toes, 298 00:16:54,466 --> 00:16:59,833 Pakicetus had tiny hooves. 299 00:16:59,833 --> 00:17:02,433 ♪ ♪ 300 00:17:02,433 --> 00:17:07,600 Pakicetus was a carnivore that hunted on land. 301 00:17:07,600 --> 00:17:13,400 But its anatomy suggests it had adapted to living in water. 302 00:17:13,400 --> 00:17:16,866 Its long snout, full of sharp teeth, 303 00:17:16,866 --> 00:17:21,366 also allowed it to probe shallow riverbeds for prey. 304 00:17:23,600 --> 00:17:27,166 Its eyes were squeezed onto the top of its head, 305 00:17:27,166 --> 00:17:30,833 so it could keep watch while swimming. 306 00:17:30,833 --> 00:17:32,633 ♪ ♪ 307 00:17:32,633 --> 00:17:36,733 And some scientists think markings on its foot bones 308 00:17:36,733 --> 00:17:41,033 are evidence it had webbing between its toes, 309 00:17:41,033 --> 00:17:44,733 allowing it to hunt underwater. 310 00:17:44,733 --> 00:17:47,966 Why was Pakicetus spending so much time in the water? 311 00:17:47,966 --> 00:17:52,300 I think it was because the water was full of fish. 312 00:17:52,300 --> 00:17:55,600 And judging from its teeth, it's pretty clear that they were 313 00:17:55,600 --> 00:17:57,800 taking advantage of that, going in the water, 314 00:17:57,800 --> 00:18:02,133 feeding on the fish, and didn't have much competition. 315 00:18:02,133 --> 00:18:05,100 And of course, it didn't take long until 316 00:18:05,100 --> 00:18:08,700 they moved into the water more permanently. 317 00:18:08,700 --> 00:18:11,966 NARRATOR: Pakicetus marks the beginning of an eventful journey 318 00:18:11,966 --> 00:18:17,400 from land animals to today's gigantic whales. 319 00:18:17,400 --> 00:18:21,466 For Philip, it was the start of a lifelong passion. 320 00:18:21,466 --> 00:18:24,666 It changed the course of my entire career because 321 00:18:24,666 --> 00:18:28,866 I got interested in this as an example of evolution. 322 00:18:28,866 --> 00:18:30,633 And it's especially interesting because 323 00:18:30,633 --> 00:18:32,766 it seems like it's backwards-- 324 00:18:32,766 --> 00:18:36,333 it's back to the sea, not out of the sea. 325 00:18:38,366 --> 00:18:40,000 ♪ ♪ 326 00:18:40,000 --> 00:18:44,466 NARRATOR: The oceans are thought to be where life started. 327 00:18:44,466 --> 00:18:47,066 Around 400 million years ago, 328 00:18:47,066 --> 00:18:52,000 some fish left the water to live on land. 329 00:18:52,000 --> 00:18:54,866 Over time, their descendants evolved 330 00:18:54,866 --> 00:18:59,166 into amphibians, dinosaurs, and mammals. 331 00:19:01,100 --> 00:19:03,666 Then, about 50 million years ago, 332 00:19:03,666 --> 00:19:06,600 something incredible happened. 333 00:19:06,600 --> 00:19:11,833 Some mammals found their way back into the water. 334 00:19:11,833 --> 00:19:15,166 They spread to all the world's oceans, 335 00:19:15,166 --> 00:19:18,666 evolving into the whales we know today, 336 00:19:18,666 --> 00:19:21,700 from huge blue and sperm whales 337 00:19:21,700 --> 00:19:25,400 to orcas and porpoises. 338 00:19:25,400 --> 00:19:29,700 ♪ ♪ 339 00:19:29,700 --> 00:19:32,733 How did this transformation happen? 340 00:19:32,733 --> 00:19:37,400 To find out, scientists examine anatomical clues 341 00:19:37,400 --> 00:19:42,366 in modern whales, as well as ancient fossils. 342 00:19:42,366 --> 00:19:43,966 By doing a dissection, 343 00:19:43,966 --> 00:19:47,833 they hope to reveal more secrets of their ancestry. 344 00:19:47,833 --> 00:19:50,200 REIDENBERG: Okay, let's unwrap. 345 00:19:50,200 --> 00:19:54,633 NARRATOR: Comparative anatomist Joy Reidenberg is investigating 346 00:19:54,633 --> 00:19:57,300 a young beaked whale that was found dead 347 00:19:57,300 --> 00:19:59,866 on the coast of the U.S.A. 348 00:20:01,166 --> 00:20:05,500 Joining her is evolutionary biologist Michael McGowen. 349 00:20:05,500 --> 00:20:07,866 It's always really sad when you have a stranded whale. 350 00:20:07,866 --> 00:20:10,533 Yeah. But for us, this is a gold mine. 351 00:20:10,533 --> 00:20:12,566 We have an opportunity here to learn something 352 00:20:12,566 --> 00:20:14,066 about an animal that's quite rare. 353 00:20:14,066 --> 00:20:17,433 These particular species are rarely sighted at the surface, 354 00:20:17,433 --> 00:20:18,833 because they just come up, 355 00:20:18,833 --> 00:20:21,366 take a quick breath, and go back down. 356 00:20:21,366 --> 00:20:23,700 REIDENBERG: What's really cool, I think, is, beaked whales 357 00:20:23,700 --> 00:20:26,333 are really adapted to stay at depth, 358 00:20:26,333 --> 00:20:27,800 and that's their norm. Yes. 359 00:20:29,033 --> 00:20:31,300 NARRATOR: Cutting into the animal's abdomen, 360 00:20:31,300 --> 00:20:33,733 they reveal something curious: 361 00:20:33,733 --> 00:20:38,133 an important clue about the origins of whales. 362 00:20:38,133 --> 00:20:39,866 That's the stomach. Uh-huh. 363 00:20:39,866 --> 00:20:41,266 Now, look at, look how weird this is. 364 00:20:42,900 --> 00:20:45,233 These animals are carnivores-- you expect them to be like a cat 365 00:20:45,233 --> 00:20:47,166 or a dog, and have one stomach chamber, 366 00:20:47,166 --> 00:20:49,466 but in fact, they don't. 367 00:20:49,466 --> 00:20:51,433 They have multiple stomach chambers, 368 00:20:51,433 --> 00:20:56,633 kind of like hoofed animals, like cattle or deer or sheep. 369 00:20:56,633 --> 00:20:58,966 So you got one, two, three, four, 370 00:20:58,966 --> 00:21:03,466 five, six, seven, eight... 371 00:21:03,466 --> 00:21:05,133 Wow. 372 00:21:05,133 --> 00:21:06,300 I think there's eight or nine chambers, 373 00:21:06,300 --> 00:21:08,166 which is crazy, when you think about it! 374 00:21:08,166 --> 00:21:09,566 It's crazy-- it's nuts. 375 00:21:12,500 --> 00:21:15,900 NARRATOR: All whales and dolphins have this unexpected feature 376 00:21:15,900 --> 00:21:20,200 of multiple stomach chambers. 377 00:21:20,200 --> 00:21:22,566 It's a trait they inherited 378 00:21:22,566 --> 00:21:25,966 from their ancient relatives that walked on land. 379 00:21:25,966 --> 00:21:29,166 MCGOWEN: Just like cows have multiple stomachs 380 00:21:29,166 --> 00:21:31,466 to digest their plant matter, 381 00:21:31,466 --> 00:21:33,133 whales have multiple stomachs 382 00:21:33,133 --> 00:21:35,800 to digest what they're eating, which is completely different-- 383 00:21:35,800 --> 00:21:37,633 fishes and squid-- 384 00:21:37,633 --> 00:21:39,433 but it's still 385 00:21:39,433 --> 00:21:43,300 coming from the same structure as a terrestrial mammal. 386 00:21:43,300 --> 00:21:46,700 It's just a throwback to their terrestrial ancestry 387 00:21:46,700 --> 00:21:48,233 of having a multi-chambered stomach 388 00:21:48,233 --> 00:21:49,700 because their ancestor did. 389 00:21:49,700 --> 00:21:52,266 ♪ ♪ 390 00:21:52,266 --> 00:21:54,366 NARRATOR: This anatomy is more evidence 391 00:21:54,366 --> 00:21:58,400 that whales are related to hoofed mammals. 392 00:21:59,866 --> 00:22:03,066 And this terrestrial heritage can even be revealed 393 00:22:03,066 --> 00:22:06,133 in their genes. 394 00:22:06,133 --> 00:22:08,966 ♪ ♪ 395 00:22:08,966 --> 00:22:14,866 In his lab, Michael uses modern whales' DNA to map their past. 396 00:22:14,866 --> 00:22:18,633 It's opening up a vast new world of information 397 00:22:18,633 --> 00:22:21,633 about the origins of whales. 398 00:22:21,633 --> 00:22:24,433 So if you think about different marine mammals, 399 00:22:24,433 --> 00:22:28,533 such as a manatee or a seal or sea lion, they all swim 400 00:22:28,533 --> 00:22:30,833 and live in the ocean and have similar adaptations 401 00:22:30,833 --> 00:22:32,900 to whales and dolphins. 402 00:22:32,900 --> 00:22:36,100 But we can look at the DNA to see whether whales 403 00:22:36,100 --> 00:22:38,066 and dolphins are closely related to those other groups 404 00:22:38,066 --> 00:22:42,000 or whether they're related to another species entirely. 405 00:22:42,000 --> 00:22:44,566 NARRATOR: Scientists wanted to identify 406 00:22:44,566 --> 00:22:46,600 the whale's closest living relative. 407 00:22:46,600 --> 00:22:48,666 So they compared 408 00:22:48,666 --> 00:22:53,533 whale DNA with a range of other animals. 409 00:22:53,533 --> 00:22:55,966 They came up with a really surprising finding. 410 00:22:55,966 --> 00:22:58,400 And the finding was that the whale's closest relative, 411 00:22:58,400 --> 00:23:00,766 using DNA, was... 412 00:23:02,433 --> 00:23:03,500 ...the hippo. 413 00:23:03,500 --> 00:23:05,266 ♪ ♪ 414 00:23:05,266 --> 00:23:07,600 NARRATOR: Whales and hippos both descended 415 00:23:07,600 --> 00:23:09,766 from a common hoofed ancestor 416 00:23:09,766 --> 00:23:13,766 that lived about five million years before Pakicetus. 417 00:23:14,966 --> 00:23:18,733 The family resemblance is striking. 418 00:23:18,733 --> 00:23:20,200 Some of the earliest whales, like Pakicetus, 419 00:23:20,200 --> 00:23:24,133 may have lived like hippos. 420 00:23:24,133 --> 00:23:26,600 Also, hippos give birth underwater. 421 00:23:26,600 --> 00:23:28,400 They nurse underwater. 422 00:23:28,400 --> 00:23:31,333 Their skin is also very thick. 423 00:23:31,333 --> 00:23:35,833 So it's interesting to think that maybe the common ancestor 424 00:23:35,833 --> 00:23:38,500 of whales and dolphins had these particular features. 425 00:23:41,266 --> 00:23:43,866 NARRATOR: But life in the ocean is very different 426 00:23:43,866 --> 00:23:46,766 from life on the riverbank. 427 00:23:46,766 --> 00:23:52,466 Over time, whales' ancestors adapted to this new environment. 428 00:23:52,466 --> 00:23:54,033 (hippos croaking) 429 00:23:54,033 --> 00:23:57,500 Scientists compared the DNA of hippos 430 00:23:57,500 --> 00:23:59,966 and whales to find out how. 431 00:23:59,966 --> 00:24:02,633 (hippos croaking) 432 00:24:02,633 --> 00:24:04,900 When we look at the genome of whales, 433 00:24:04,900 --> 00:24:08,900 we see that whales still have a lot of the genes 434 00:24:08,900 --> 00:24:11,100 from when they used to live on land. 435 00:24:11,100 --> 00:24:13,200 So they still have genes involved in smelling, 436 00:24:13,200 --> 00:24:17,833 sweat glands, color vision, producing saliva. 437 00:24:17,833 --> 00:24:21,933 But these genes are inactivated, and they gradually degrade. 438 00:24:21,933 --> 00:24:24,433 But I think this is incredibly powerful evidence that shows 439 00:24:24,433 --> 00:24:27,166 that whales come from land ancestors, 440 00:24:27,166 --> 00:24:29,833 that they still have these genes in their genomes, 441 00:24:29,833 --> 00:24:31,833 even though they're inactivated. 442 00:24:33,433 --> 00:24:35,500 NARRATOR: Over millions of years, 443 00:24:35,500 --> 00:24:38,266 whales lost many traits beneficial on land 444 00:24:38,266 --> 00:24:43,100 that had no use in water. 445 00:24:43,100 --> 00:24:47,733 But what happened to that most vital land animal feature, 446 00:24:47,733 --> 00:24:50,400 legs? 447 00:24:50,400 --> 00:24:54,933 ♪ ♪ 448 00:24:54,933 --> 00:24:58,800 In Egypt, Hesham Sallam's mission is to find fossils 449 00:24:58,800 --> 00:25:04,066 that can tell us more about how whales became fully aquatic. 450 00:25:05,400 --> 00:25:07,833 He's leaving Wadi Hitan to search 451 00:25:07,833 --> 00:25:12,200 a nearby unexplored area with older rock deposits. 452 00:25:14,900 --> 00:25:16,900 SALLAM: Here we are. 453 00:25:16,900 --> 00:25:19,600 (brake engages, engine stops) 454 00:25:19,600 --> 00:25:21,200 Ready to find fossils? 455 00:25:21,200 --> 00:25:22,833 AL-ASHQAR: Sure. 456 00:25:25,966 --> 00:25:28,933 NARRATOR: Joining him are fellow paleontologists 457 00:25:28,933 --> 00:25:34,633 Shorouq Al-Ashqar and Abdullah Gohar. 458 00:25:34,633 --> 00:25:38,633 From geological maps, they know this part of the ancient seabed 459 00:25:38,633 --> 00:25:41,866 is about two million years older than the deposits 460 00:25:41,866 --> 00:25:45,566 where the giant Basilosaurus was found. 461 00:25:45,566 --> 00:25:47,866 They're searching for intermediate fossils 462 00:25:47,866 --> 00:25:51,866 that might shed light on how four-legged land mammals 463 00:25:51,866 --> 00:25:55,733 evolved into their fully aquatic descendants. 464 00:25:55,733 --> 00:25:57,900 SALLAM: I'm hoping to find maybe 465 00:25:57,900 --> 00:26:02,933 a full skeleton of, uh, 466 00:26:02,933 --> 00:26:04,366 some ancient whales 467 00:26:04,366 --> 00:26:06,600 that we didn't know much about. 468 00:26:06,600 --> 00:26:08,933 If we're lucky to find that, 469 00:26:08,933 --> 00:26:11,033 this prehistoric animal here 470 00:26:11,033 --> 00:26:13,333 might have sturdy legs 471 00:26:13,333 --> 00:26:16,433 that can actually lift the body out of the water. 472 00:26:16,433 --> 00:26:18,633 So this is what I'm trying to do, 473 00:26:18,633 --> 00:26:22,200 is find more primitive whales, 474 00:26:22,200 --> 00:26:28,133 and this is going to happen in, in maybe, 475 00:26:28,133 --> 00:26:32,833 in a few hours, few weeks, few months. 476 00:26:32,833 --> 00:26:35,433 It depends how luck we have. 477 00:26:35,433 --> 00:26:39,333 ♪ ♪ 478 00:26:39,333 --> 00:26:43,166 NARRATOR: And it's not long before fossils start to appear. 479 00:26:43,166 --> 00:26:45,133 Wow! Look at this! 480 00:26:45,133 --> 00:26:46,700 SALLAM: Hey, what have you found? 481 00:26:46,700 --> 00:26:48,600 We have a monster here. 482 00:26:48,600 --> 00:26:52,300 Oh, my word. A giant... 483 00:26:52,300 --> 00:26:54,733 This is incredible. 484 00:26:54,733 --> 00:26:56,866 Yeah. Look at this beast. 485 00:26:56,866 --> 00:26:58,500 Yes. 486 00:26:58,500 --> 00:27:01,233 This is a shark tooth. 487 00:27:01,233 --> 00:27:05,166 This is really huge shark. 488 00:27:06,366 --> 00:27:09,866 NARRATOR: But there's still no sign of a whale. 489 00:27:13,733 --> 00:27:16,033 And then... 490 00:27:16,033 --> 00:27:17,633 SALLAM: Hey! 491 00:27:17,633 --> 00:27:19,033 NARRATOR: They've found something. 492 00:27:19,033 --> 00:27:20,766 Look at this. 493 00:27:22,466 --> 00:27:24,366 Right here. 494 00:27:24,366 --> 00:27:26,533 A small vertebra. 495 00:27:26,533 --> 00:27:27,666 GOHAR: Oh. AL-ASHQAR: Wow. 496 00:27:27,666 --> 00:27:28,866 SALLAM: Right there, another one here. 497 00:27:28,866 --> 00:27:30,733 GOHAR: Amazing. SALLAM: Another one there. 498 00:27:30,733 --> 00:27:32,666 So it seems like a... 499 00:27:32,666 --> 00:27:35,466 Um, a complete skeleton here. Yeah. 500 00:27:35,466 --> 00:27:37,533 Look at this line up. 501 00:27:37,533 --> 00:27:42,133 Could be the vertebral column going that way. 502 00:27:42,133 --> 00:27:44,966 But this is definitely not Basilosaurus. 503 00:27:44,966 --> 00:27:49,533 The size of the vertebra is quite small. 504 00:27:49,533 --> 00:27:53,100 ♪ ♪ 505 00:27:54,666 --> 00:27:56,266 NARRATOR: With his expert eye, 506 00:27:56,266 --> 00:27:59,633 Hesham can recognize the shape of the bones immediately. 507 00:27:59,633 --> 00:28:02,400 I think this is a, a skeleton, 508 00:28:02,400 --> 00:28:05,733 and I do believe might be the skull over there. 509 00:28:05,733 --> 00:28:07,633 Really exciting. 510 00:28:07,633 --> 00:28:09,566 ♪ ♪ 511 00:28:09,566 --> 00:28:10,866 NARRATOR: Could it provide clues 512 00:28:10,866 --> 00:28:13,966 to how whales lost their legs? 513 00:28:13,966 --> 00:28:16,966 So this is definitely older than Basilosaurus, 514 00:28:16,966 --> 00:28:18,633 because the Basilosaurus 515 00:28:18,633 --> 00:28:21,866 come later, in the younger deposits. 516 00:28:21,866 --> 00:28:25,433 So this might be a kind of amphibious lifestyle whale, 517 00:28:25,433 --> 00:28:29,633 but with really sturdy hind limb. 518 00:28:29,633 --> 00:28:30,833 If we are lucky enough, 519 00:28:30,833 --> 00:28:33,100 we might find the pelvis somewhere 520 00:28:33,100 --> 00:28:34,466 and the hind limbs right here. 521 00:28:34,466 --> 00:28:40,133 ♪ ♪ 522 00:28:40,133 --> 00:28:42,066 NARRATOR: Before they can find out more, 523 00:28:42,066 --> 00:28:43,766 they hit a problem. 524 00:28:43,766 --> 00:28:46,533 (wind roaring) 525 00:28:46,533 --> 00:28:51,300 If it's actually getting too windy, 526 00:28:51,300 --> 00:28:53,700 we just have to leave the site and come 527 00:28:53,700 --> 00:28:56,366 when the nature calm down. 528 00:28:56,366 --> 00:28:58,033 I think we should stop. 529 00:28:59,566 --> 00:29:02,833 NARRATOR: They mark the spot so they can return to it later. 530 00:29:04,266 --> 00:29:08,000 Until then, this whale's place in the family tree 531 00:29:08,000 --> 00:29:10,433 will remain unknown. 532 00:29:12,900 --> 00:29:18,600 ♪ ♪ 533 00:29:19,800 --> 00:29:22,766 Meanwhile, in their lab at Mansoura University, 534 00:29:22,766 --> 00:29:25,466 Hesham and Abdullah are investigating 535 00:29:25,466 --> 00:29:28,000 another new piece of the puzzle. 536 00:29:28,000 --> 00:29:31,900 ♪ ♪ 537 00:29:33,300 --> 00:29:36,800 This is one of the most important discovery. 538 00:29:36,800 --> 00:29:40,633 Here we have nearly complete skull, 539 00:29:40,633 --> 00:29:42,166 a lower jaw, 540 00:29:42,166 --> 00:29:43,566 some of the vertebrae, 541 00:29:43,566 --> 00:29:46,700 and some of the broken ribs. 542 00:29:48,500 --> 00:29:52,633 NARRATOR: This is a previously unknown species of ancient whale. 543 00:29:54,166 --> 00:29:57,833 Abdullah has named it Phiomicetus anubis, 544 00:29:57,833 --> 00:29:59,433 after Anubis, 545 00:29:59,433 --> 00:30:03,166 the ancient Egyptian god of death. 546 00:30:03,166 --> 00:30:05,166 GOHAR: We have a clear indication 547 00:30:05,166 --> 00:30:07,200 of very powerful predator 548 00:30:07,200 --> 00:30:10,300 that hunt everything around him. 549 00:30:10,300 --> 00:30:13,200 So we clearly can consider him 550 00:30:13,200 --> 00:30:16,133 the god of death for all living animal 551 00:30:16,133 --> 00:30:19,200 that lived by him 43 million years ago. 552 00:30:19,200 --> 00:30:21,566 NARRATOR: It's one of the oldest whale fossils 553 00:30:21,566 --> 00:30:24,366 ever unearthed in Africa. 554 00:30:24,366 --> 00:30:29,666 But could it walk on land, like its ancestor Pakicetus? 555 00:30:29,666 --> 00:30:31,533 The team hasn't found leg bones, 556 00:30:31,533 --> 00:30:35,566 so they must look for other evidence. 557 00:30:35,566 --> 00:30:37,833 Abdullah has found a clue 558 00:30:37,833 --> 00:30:40,733 in a bony projection on one of the vertebrae. 559 00:30:40,733 --> 00:30:44,166 This is a thoracic vertebra from the rib cage region, 560 00:30:44,166 --> 00:30:46,900 and you can see, this sticking-out bone here 561 00:30:46,900 --> 00:30:48,533 is called neural spine. 562 00:30:48,533 --> 00:30:51,700 It's very short in human, here, 563 00:30:51,700 --> 00:30:56,200 but this is very clear evidence of walking lifestyle, 564 00:30:56,200 --> 00:30:59,866 because the longer this sticking-out bone, 565 00:30:59,866 --> 00:31:03,100 the more ability to hold massive muscles 566 00:31:03,100 --> 00:31:06,566 that support the walking on four legs. 567 00:31:06,566 --> 00:31:09,500 So, land mammals have this 568 00:31:09,500 --> 00:31:13,300 very long neural spine here. 569 00:31:13,300 --> 00:31:16,900 This is a cow. 570 00:31:16,900 --> 00:31:20,433 SALLAM: But if you look at the modern dolphin, 571 00:31:20,433 --> 00:31:25,666 you can see clearly this sticking neural spine 572 00:31:25,666 --> 00:31:27,966 is much, much shorter 573 00:31:27,966 --> 00:31:32,500 comparing to the walking terrestrial animal. 574 00:31:32,500 --> 00:31:34,333 So this is fully aquatic, 575 00:31:34,333 --> 00:31:35,933 this is fully terrestrial, 576 00:31:35,933 --> 00:31:37,566 and anubis in between. 577 00:31:39,133 --> 00:31:43,766 NARRATOR: The team believes that if anubis had strong back muscles, 578 00:31:43,766 --> 00:31:46,466 it probably used them for walking. 579 00:31:46,466 --> 00:31:50,466 ♪ ♪ 580 00:31:50,466 --> 00:31:52,500 Anubis, the god of death, 581 00:31:52,500 --> 00:31:55,733 was a formidable marine predator. 582 00:31:55,733 --> 00:31:59,033 It measured around ten feet long 583 00:31:59,033 --> 00:32:03,300 and weighed over half a ton. 584 00:32:03,300 --> 00:32:06,266 It spent extended periods in the sea, 585 00:32:06,266 --> 00:32:09,166 where it hunted fish and turtles. 586 00:32:13,400 --> 00:32:16,333 But from the bones the team has found, 587 00:32:16,333 --> 00:32:18,966 they think it was able to come back to land, 588 00:32:18,966 --> 00:32:22,066 perhaps to breed. 589 00:32:22,066 --> 00:32:25,833 And it didn't wriggle out of the water like a seal. 590 00:32:25,833 --> 00:32:29,933 Anubis was probably a walking whale. 591 00:32:34,066 --> 00:32:35,366 Where can I put it? 592 00:32:35,366 --> 00:32:37,933 (man speaking off mic) Thank you. 593 00:32:37,933 --> 00:32:39,433 NARRATOR: To find out more about 594 00:32:39,433 --> 00:32:41,833 anubis's place in the whale family tree, 595 00:32:41,833 --> 00:32:44,100 Hesham and Abdullah take the skull 596 00:32:44,100 --> 00:32:47,100 to a nearby hospital for a CT scan. 597 00:32:47,100 --> 00:32:49,166 ♪ ♪ 598 00:32:49,166 --> 00:32:50,533 Shall we get outside now? 599 00:32:50,533 --> 00:32:51,733 MOHAMMED: Yes, yes, yes, outside. 600 00:32:51,733 --> 00:32:57,433 ♪ ♪ 601 00:32:57,433 --> 00:33:00,366 Can you go inside? 602 00:33:00,366 --> 00:33:02,600 NARRATOR: Hesham wants to take a closer look 603 00:33:02,600 --> 00:33:05,166 at the position of anubis's nostrils... 604 00:33:05,166 --> 00:33:06,633 Okay, 605 00:33:06,633 --> 00:33:09,066 can you zoom out, please? 606 00:33:09,066 --> 00:33:12,033 NARRATOR: ...and spots something striking. 607 00:33:12,033 --> 00:33:13,700 So here in anubis, 608 00:33:13,700 --> 00:33:16,633 the tip of the snout is broken off, 609 00:33:16,633 --> 00:33:19,033 and it could be up to here, 610 00:33:19,033 --> 00:33:22,633 but the nasal opening would be right here, 611 00:33:22,633 --> 00:33:26,200 one-third the way back in the snout. 612 00:33:26,200 --> 00:33:28,700 Comparing to the modern whale, 613 00:33:28,700 --> 00:33:31,333 the blowhole would be on the top of the skull. 614 00:33:32,833 --> 00:33:37,633 NARRATOR: Land mammals' nostrils are at the tip of the nose. 615 00:33:37,633 --> 00:33:39,533 Modern whales' nostrils have moved to 616 00:33:39,533 --> 00:33:42,666 the top of their heads to become blowholes. 617 00:33:46,800 --> 00:33:48,800 But anubis's nostrils are 618 00:33:48,800 --> 00:33:52,500 a third of the way back on its snout. 619 00:33:52,500 --> 00:33:56,933 It's one step closer to becoming fully aquatic. 620 00:34:00,366 --> 00:34:03,066 So, how did walking whales 621 00:34:03,066 --> 00:34:06,566 lose their legs to become modern whales? 622 00:34:06,566 --> 00:34:08,900 Back at Wadi Hitan, 623 00:34:08,900 --> 00:34:13,833 Hesham takes a closer look at Basilosaurus. 624 00:34:14,966 --> 00:34:17,133 This huge marine predator 625 00:34:17,133 --> 00:34:21,600 evolved about three million years after anubis. 626 00:34:21,600 --> 00:34:25,200 But could it support itself on land? 627 00:34:25,200 --> 00:34:27,200 Here is the arm of this beast. 628 00:34:27,200 --> 00:34:33,033 It's actually wasn't like a regular arm of a mammal's, 629 00:34:33,033 --> 00:34:37,166 but flippers, to allow it to swim in the sea. 630 00:34:37,166 --> 00:34:42,733 NARRATOR: Basilosaurus's front legs have turned into flippers. 631 00:34:42,733 --> 00:34:44,666 And at the back of the animal 632 00:34:44,666 --> 00:34:47,033 is something even more intriguing. 633 00:34:48,033 --> 00:34:49,366 This is really something 634 00:34:49,366 --> 00:34:52,600 very cool in the whale evolution. 635 00:34:52,600 --> 00:34:56,366 This is the hind limb of this monster, 636 00:34:56,366 --> 00:34:58,666 and this is a complete pelvis. 637 00:34:58,666 --> 00:35:01,366 Would be underneath 638 00:35:01,366 --> 00:35:03,733 one of these vertebrae, like that. 639 00:35:03,733 --> 00:35:06,500 And this is the whole legs 640 00:35:06,500 --> 00:35:10,600 of this really huge animal. 641 00:35:10,600 --> 00:35:12,800 This is the right leg-- 642 00:35:12,800 --> 00:35:15,266 the thigh bone, 643 00:35:15,266 --> 00:35:18,500 the shinbone, 644 00:35:18,500 --> 00:35:21,366 and the foot. 645 00:35:23,100 --> 00:35:25,933 ♪ ♪ 646 00:35:25,933 --> 00:35:29,366 NARRATOR: These casts show that Basilosaurus's legs 647 00:35:29,366 --> 00:35:34,366 were smaller than the arms of a human. 648 00:35:34,366 --> 00:35:37,033 Definitely Basilosaurus cannot walk, 649 00:35:37,033 --> 00:35:40,833 given the size of these hind limbs 650 00:35:40,833 --> 00:35:45,200 comparing to the whole body, 20 meter long. 651 00:35:45,200 --> 00:35:50,400 Just totally cannot support walking on land. 652 00:35:50,400 --> 00:35:54,766 Just like T. rex hand, do nothing. 653 00:35:54,766 --> 00:35:58,900 ♪ ♪ 654 00:35:58,900 --> 00:36:01,666 NARRATOR: Unlike its walking whale ancestors, 655 00:36:01,666 --> 00:36:05,066 Basilosaurus was fully aquatic. 656 00:36:09,500 --> 00:36:11,633 But in modern whales, 657 00:36:11,633 --> 00:36:16,800 are there any remnants of their walking past? 658 00:36:16,800 --> 00:36:18,800 Back in the lab, 659 00:36:18,800 --> 00:36:21,266 Joy Reidenberg and Michael McGowen 660 00:36:21,266 --> 00:36:24,266 are looking for more clues inside the beaked whale. 661 00:36:24,266 --> 00:36:26,433 We're now looking at the flank area, 662 00:36:26,433 --> 00:36:27,600 and I'm going to show you 663 00:36:27,600 --> 00:36:29,233 something really cool in this area. 664 00:36:29,233 --> 00:36:31,800 Right in here is a small bone. 665 00:36:31,800 --> 00:36:34,466 Something that is really a throwback 666 00:36:34,466 --> 00:36:37,933 to the ancestral condition of having hind legs. 667 00:36:37,933 --> 00:36:42,933 All that's left is a little remnant of a pelvis. 668 00:36:42,933 --> 00:36:44,833 NARRATOR: This tiny pelvic bone 669 00:36:44,833 --> 00:36:47,066 is hidden in the whale's hind quarters, 670 00:36:47,066 --> 00:36:51,333 where hips would once have been. 671 00:36:51,333 --> 00:36:52,966 The only thing it doesn't have is 672 00:36:52,966 --> 00:36:55,566 the connection back to the spine. 673 00:36:55,566 --> 00:36:57,233 So ours is connected in the back to the spine. 674 00:36:57,233 --> 00:36:58,600 This one is just free-floating. 675 00:36:58,600 --> 00:37:00,700 It's tiny-- it's actually 676 00:37:00,700 --> 00:37:02,466 a lot smaller than I thought it was gonna be. 677 00:37:02,466 --> 00:37:04,233 This pelvis is so interesting, 678 00:37:04,233 --> 00:37:05,733 because it's a throwback 679 00:37:05,733 --> 00:37:06,966 to the land animals 680 00:37:06,966 --> 00:37:08,600 that were using a pelvis for walking. 681 00:37:08,600 --> 00:37:09,766 But whales aren't walking. 682 00:37:09,766 --> 00:37:11,500 They don't have hind legs. 683 00:37:11,500 --> 00:37:13,733 ♪ ♪ 684 00:37:13,733 --> 00:37:16,300 NARRATOR: All modern whales still have a pelvis, 685 00:37:16,300 --> 00:37:21,133 and some have tiny hidden leg bones, too. 686 00:37:21,133 --> 00:37:24,900 But why would a whale need a pelvis? 687 00:37:24,900 --> 00:37:26,600 It still has function. 688 00:37:26,600 --> 00:37:28,166 Part of that function 689 00:37:28,166 --> 00:37:30,933 is to anchor the muscles of the belly for swimming, 690 00:37:30,933 --> 00:37:32,800 so it's still being used in locomotion, 691 00:37:32,800 --> 00:37:34,033 just not with legs. 692 00:37:34,033 --> 00:37:35,766 So think about, in the front, you know, 693 00:37:35,766 --> 00:37:37,500 we have the six-pack muscles? Yeah. 694 00:37:37,500 --> 00:37:39,233 These help to bend the body 695 00:37:39,233 --> 00:37:41,300 in this downward motion like that. 696 00:37:41,300 --> 00:37:43,366 So that's part of the swimming action. 697 00:37:43,366 --> 00:37:44,900 Oh, wow, okay. 698 00:37:44,900 --> 00:37:46,366 They anchor on this bone. 699 00:37:46,366 --> 00:37:47,500 They anchor in other places, too, 700 00:37:47,500 --> 00:37:48,666 but they also anchor on this bone. 701 00:37:49,666 --> 00:37:52,233 MCGOWEN: And that's another remnant of its mammal past, 702 00:37:52,233 --> 00:37:55,100 is that they move their spine up and down. 703 00:37:55,100 --> 00:37:56,666 And with fish 704 00:37:56,666 --> 00:37:58,966 and even reptiles, they move side to side. 705 00:37:58,966 --> 00:38:00,166 You watch a snake move, 706 00:38:00,166 --> 00:38:01,466 you watch a crocodile walking, 707 00:38:01,466 --> 00:38:03,033 they're swimming like fish, 708 00:38:03,033 --> 00:38:04,533 but on the land, with legs. Yeah. 709 00:38:04,533 --> 00:38:06,233 When you get to mammals, 710 00:38:06,233 --> 00:38:07,633 the legs come underneath, 711 00:38:07,633 --> 00:38:09,733 the spine and the body come off the ground, 712 00:38:09,733 --> 00:38:12,733 and now they're free to gallop. 713 00:38:12,733 --> 00:38:17,233 ♪ ♪ 714 00:38:17,233 --> 00:38:18,966 And when whales went 715 00:38:18,966 --> 00:38:20,600 back into the water, 716 00:38:20,600 --> 00:38:22,233 they kept the up and down spinal movement, 717 00:38:22,233 --> 00:38:24,100 so they're still galloping. 718 00:38:24,100 --> 00:38:25,933 In the water! 719 00:38:25,933 --> 00:38:29,100 ♪ ♪ 720 00:38:35,200 --> 00:38:37,933 ♪ ♪ 721 00:38:37,933 --> 00:38:39,866 NARRATOR: Losing their legs 722 00:38:39,866 --> 00:38:41,866 was just one change whales underwent 723 00:38:41,866 --> 00:38:45,500 as they adapted to life in the ocean. 724 00:38:45,500 --> 00:38:48,500 ♪ ♪ 725 00:38:48,500 --> 00:38:51,000 To survive in this underwater environment, 726 00:38:51,000 --> 00:38:56,133 whales' limbs grew stronger, making swimming easier. 727 00:38:56,133 --> 00:38:59,666 They grew horizontal flukes on the ends of their tails, 728 00:38:59,666 --> 00:39:02,700 and front limbs began to turn into flippers 729 00:39:02,700 --> 00:39:05,500 for stability and steering. 730 00:39:05,500 --> 00:39:08,766 As they moved to tail-powered swimming, 731 00:39:08,766 --> 00:39:11,433 their bodies became more streamlined, 732 00:39:11,433 --> 00:39:13,866 hind limbs shrank, 733 00:39:13,866 --> 00:39:17,466 and their spines grew longer. 734 00:39:17,466 --> 00:39:20,533 They had become fully aquatic 735 00:39:20,533 --> 00:39:23,400 and were unable to return to the land. 736 00:39:27,600 --> 00:39:33,200 ♪ ♪ 737 00:39:35,233 --> 00:39:38,666 The desert at Wadi Hitan is dotted with the skeletons 738 00:39:38,666 --> 00:39:41,633 of some of the first ancient whales. 739 00:39:41,633 --> 00:39:44,600 But around 34 million years ago, 740 00:39:44,600 --> 00:39:49,400 they mysteriously vanish from the fossil record here. 741 00:39:49,400 --> 00:39:54,533 In an area about 50 miles from Wadi Hitan, 742 00:39:54,533 --> 00:39:56,933 Shorouq Al-Ashqar investigates 743 00:39:56,933 --> 00:40:01,600 why the whales disappeared from this region. 744 00:40:02,933 --> 00:40:06,866 These strange objects provide an answer. 745 00:40:06,866 --> 00:40:09,133 AL-ASHQAR: This is fossilized wood. 746 00:40:09,133 --> 00:40:12,633 It seems like wood, but it's rock. 747 00:40:12,633 --> 00:40:15,366 The wood replaced by silica and minerals, 748 00:40:15,366 --> 00:40:19,300 so it's so heavy, but it's a good indication 749 00:40:19,300 --> 00:40:22,800 that this area one day was a forest. 750 00:40:22,800 --> 00:40:27,233 The trees were very tall, 40 to 50 meters long, 751 00:40:27,233 --> 00:40:30,633 colorful birds flying in the area. 752 00:40:30,633 --> 00:40:33,833 Turtles, snakes-- full of life. 753 00:40:35,433 --> 00:40:40,366 NARRATOR: The fossilized wood is around 34 million years old. 754 00:40:40,366 --> 00:40:44,133 It's a sign that this area, once a thriving ocean, 755 00:40:44,133 --> 00:40:47,200 underwent a dramatic change. 756 00:40:47,200 --> 00:40:51,033 ♪ ♪ 757 00:40:51,033 --> 00:40:56,500 At that time, Earth's climate began to cool. 758 00:40:56,500 --> 00:40:58,566 The Antarctic ice sheet formed 759 00:40:58,566 --> 00:41:01,600 and sea levels dropped. 760 00:41:01,600 --> 00:41:06,333 The Tethys Ocean receded, forming the Mediterranean. 761 00:41:06,333 --> 00:41:10,066 And where whales once swam in warm, shallow waters, 762 00:41:10,066 --> 00:41:14,133 a forest grew. 763 00:41:14,133 --> 00:41:17,100 The primitive whales that lived in Wadi Hitan, 764 00:41:17,100 --> 00:41:20,366 all of them are, died out. 765 00:41:20,366 --> 00:41:25,500 Fortunately, some of whales adapt with the climatic change. 766 00:41:25,500 --> 00:41:27,166 Whales are mammals, 767 00:41:27,166 --> 00:41:29,633 and mammals are warm-blooded bodies, 768 00:41:29,633 --> 00:41:32,100 so they can adapt with the cold water 769 00:41:32,100 --> 00:41:34,233 and find new places to live in. 770 00:41:34,233 --> 00:41:36,200 ♪ ♪ 771 00:41:36,200 --> 00:41:37,766 NARRATOR: Being warm-blooded, 772 00:41:37,766 --> 00:41:40,600 they were able to generate their own heat 773 00:41:40,600 --> 00:41:43,666 and grow blubber to insulate their bodies from the cold, 774 00:41:43,666 --> 00:41:49,500 allowing them to migrate and thrive all over the world. 775 00:41:49,500 --> 00:41:53,700 But the whale's story doesn't end there. 776 00:41:57,033 --> 00:42:00,833 ♪ ♪ 777 00:42:00,833 --> 00:42:03,066 In a warehouse at the 778 00:42:03,066 --> 00:42:05,666 Smithsonian National Museum of Natural History 779 00:42:05,666 --> 00:42:10,533 is the world's largest whale bone collection. 780 00:42:10,533 --> 00:42:14,933 It holds remains from nearly 10,000 whales. 781 00:42:17,033 --> 00:42:20,966 Evolutionary biologist Ellen Coombs scans their skulls 782 00:42:20,966 --> 00:42:24,366 to investigate how they changed over time. 783 00:42:27,133 --> 00:42:29,400 Studying the skull is really important, 784 00:42:29,400 --> 00:42:30,833 because in whales, 785 00:42:30,833 --> 00:42:32,033 it's where a lot of changes have happened 786 00:42:32,033 --> 00:42:34,166 over their evolutionary history, 787 00:42:34,166 --> 00:42:36,100 because it houses a lot of sensory organs-- 788 00:42:36,100 --> 00:42:38,833 the eyes, the nose, the brain-- 789 00:42:38,833 --> 00:42:40,433 and this can tell us lots of things 790 00:42:40,433 --> 00:42:41,933 about how the animal has evolved to eat 791 00:42:41,933 --> 00:42:43,333 and live its life. 792 00:42:45,566 --> 00:42:49,033 NARRATOR: The 3D scans allow Ellen to look in detail 793 00:42:49,033 --> 00:42:50,866 at the more recent chapters 794 00:42:50,866 --> 00:42:54,933 in the whale's evolutionary tale. 795 00:42:54,933 --> 00:42:57,866 ♪ ♪ 796 00:42:57,866 --> 00:43:00,966 When the last of the ancient whales died out, 797 00:43:00,966 --> 00:43:05,133 the modern whale's journey began. 798 00:43:05,133 --> 00:43:08,400 And as the family tree continued to grow, 799 00:43:08,400 --> 00:43:11,733 something surprising happened. 800 00:43:11,733 --> 00:43:13,633 Some kept their teeth, 801 00:43:13,633 --> 00:43:18,233 like orcas, sperm whales, and dolphins. 802 00:43:18,233 --> 00:43:21,966 And some, like the blue, humpback, and right whales, 803 00:43:21,966 --> 00:43:23,733 lost their teeth 804 00:43:23,733 --> 00:43:26,200 and developed a new filter-feeding tool 805 00:43:26,200 --> 00:43:29,833 called baleen. 806 00:43:33,366 --> 00:43:35,733 This is the underside of the mouth of a humpback whale, 807 00:43:35,733 --> 00:43:37,466 which is one of the baleen whales. 808 00:43:37,466 --> 00:43:39,166 And what makes it a baleen whale 809 00:43:39,166 --> 00:43:40,700 is what's going on here. 810 00:43:40,700 --> 00:43:41,933 So this is baleen. 811 00:43:41,933 --> 00:43:44,066 This sits where teeth would normally sit 812 00:43:44,066 --> 00:43:46,166 in something like a killer whale or a dolphin. 813 00:43:46,166 --> 00:43:49,066 But instead, they have these amazing plates of baleen, 814 00:43:49,066 --> 00:43:51,800 which are made of keratin, just like our hair or nails. 815 00:43:51,800 --> 00:43:52,966 And you can see that it has 816 00:43:52,966 --> 00:43:54,433 these kind of hairs on the end here, 817 00:43:54,433 --> 00:43:55,933 which are used to filter out prey. 818 00:43:55,933 --> 00:43:57,400 And what they do is, they suck in 819 00:43:57,400 --> 00:44:00,133 a big mouthful of water full of fish or krill, 820 00:44:00,133 --> 00:44:01,400 which is what they eat, 821 00:44:01,400 --> 00:44:02,900 and then they use their tongue 822 00:44:02,900 --> 00:44:05,833 to force out that water and capture all of their prey 823 00:44:05,833 --> 00:44:07,200 in these plates of baleen. 824 00:44:07,200 --> 00:44:09,233 And that is sometimes up to 825 00:44:09,233 --> 00:44:11,800 half a million calories in one mouthful. 826 00:44:11,800 --> 00:44:18,200 ♪ ♪ 827 00:44:21,933 --> 00:44:25,366 ♪ ♪ 828 00:44:27,200 --> 00:44:29,800 NARRATOR: Why did these whales take such a different path 829 00:44:29,800 --> 00:44:31,966 from their toothed cousins? 830 00:44:31,966 --> 00:44:34,466 COOMBS: Here we can see a blue whale skull. 831 00:44:34,466 --> 00:44:36,166 The main thing that we see here 832 00:44:36,166 --> 00:44:39,000 is how flat the face is, 833 00:44:39,000 --> 00:44:41,666 how wide the mouth is, 834 00:44:41,666 --> 00:44:43,666 and these are perfect adaptations 835 00:44:43,666 --> 00:44:45,600 for mass filter feeding with baleen. 836 00:44:45,600 --> 00:44:48,833 NARRATOR: Meanwhile, the toothed whale has evolved 837 00:44:48,833 --> 00:44:51,100 a very different skull shape. 838 00:44:51,100 --> 00:44:52,666 So, if we take a look 839 00:44:52,666 --> 00:44:54,300 at the skull of this killer whale from the side, 840 00:44:54,300 --> 00:44:55,700 you can see that 841 00:44:55,700 --> 00:44:57,166 the forehead is concave. 842 00:44:57,166 --> 00:44:58,833 This is because it houses a load of organs 843 00:44:58,833 --> 00:45:01,400 that are used for echolocation. 844 00:45:01,400 --> 00:45:06,600 (dolphins clicking and chirping) 845 00:45:06,600 --> 00:45:10,000 NARRATOR: The highly specialized skill of echolocation 846 00:45:10,000 --> 00:45:13,933 has evolved in some animals, like bats and whales. 847 00:45:13,933 --> 00:45:16,833 (dolphins clicking and chirping) 848 00:45:16,833 --> 00:45:20,333 Whales "see" by emitting high-frequency sounds 849 00:45:20,333 --> 00:45:22,033 and then listening for 850 00:45:22,033 --> 00:45:24,133 how they bounce back off objects 851 00:45:24,133 --> 00:45:27,133 to find prey in the depths of the ocean. 852 00:45:27,133 --> 00:45:32,600 (dolphins clicking and chirping) 853 00:45:32,600 --> 00:45:34,933 (squeaking) 854 00:45:34,933 --> 00:45:36,366 Toothed whales do this 855 00:45:36,366 --> 00:45:39,000 in a very specialized apparatus in their forehead, 856 00:45:39,000 --> 00:45:41,000 the key ones being the phonic lips, 857 00:45:41,000 --> 00:45:43,266 which make a high-frequency clicking sound, 858 00:45:43,266 --> 00:45:46,266 and the melon, which is a fatty organ, 859 00:45:46,266 --> 00:45:48,333 which helps to focus these high-frequency sounds 860 00:45:48,333 --> 00:45:49,766 as they leave the animal. 861 00:45:49,766 --> 00:45:51,333 (dolphins chirping) 862 00:45:51,333 --> 00:45:54,666 NARRATOR: But how this skill evolved is still a mystery. 863 00:45:54,666 --> 00:45:56,733 ♪ ♪ 864 00:45:56,733 --> 00:45:58,766 COOMBS: So we have ancient whales dying out 865 00:45:58,766 --> 00:46:00,400 that we know they could not echolocate. 866 00:46:00,400 --> 00:46:02,433 And then we have the appearance 867 00:46:02,433 --> 00:46:04,466 of the early toothed whales that could echolocate. 868 00:46:04,466 --> 00:46:06,300 So there's a gap in there, 869 00:46:06,300 --> 00:46:08,100 where there'll be several fossils 870 00:46:08,100 --> 00:46:10,366 that have maybe very basic echolocation, 871 00:46:10,366 --> 00:46:12,633 and they're the fossils that we really need to find. 872 00:46:12,633 --> 00:46:15,200 (orcas squealing) 873 00:46:15,200 --> 00:46:18,066 NARRATOR: Scientists think these early whales survived 874 00:46:18,066 --> 00:46:20,500 to pass on their genes to their offspring, 875 00:46:20,500 --> 00:46:23,266 and so their abilities gradually improved. 876 00:46:23,266 --> 00:46:26,400 (orcas clicking and squealing) 877 00:46:26,400 --> 00:46:30,300 Today, some toothed whales are such efficient predators, 878 00:46:30,300 --> 00:46:32,300 they even hunt their baleen cousins. 879 00:46:32,300 --> 00:46:34,933 ♪ ♪ 880 00:46:34,933 --> 00:46:39,266 So these humpbacks have evolved new survival strategies. 881 00:46:41,866 --> 00:46:48,033 ♪ ♪ 882 00:46:48,033 --> 00:46:50,500 Back in the Dominican Republic, 883 00:46:50,500 --> 00:46:54,166 Joy Reidenberg and marine biologist Mithriel MacKay 884 00:46:54,166 --> 00:46:56,666 are on a whale-watching mission. 885 00:46:56,666 --> 00:46:58,266 There's a blow, 886 00:46:58,266 --> 00:47:00,533 around 1:00. 887 00:47:00,533 --> 00:47:01,866 And the third. Yeah. 888 00:47:01,866 --> 00:47:03,666 And four. 889 00:47:03,666 --> 00:47:07,066 There's four there. 890 00:47:07,066 --> 00:47:10,466 NARRATOR: Most whales live in family groups 891 00:47:10,466 --> 00:47:13,933 and have complex social lives. 892 00:47:13,933 --> 00:47:16,400 Mithriel and Joy want to understand 893 00:47:16,400 --> 00:47:18,600 how certain behaviors 894 00:47:18,600 --> 00:47:21,633 give them an evolutionary advantage. 895 00:47:21,633 --> 00:47:23,000 MACKAY: We look at the behaviors 896 00:47:23,000 --> 00:47:25,433 and then we start asking questions. 897 00:47:25,433 --> 00:47:26,800 Why are they doing those things? 898 00:47:26,800 --> 00:47:30,066 Because the answer to the why 899 00:47:30,066 --> 00:47:32,700 gives us the reason they evolved this way. Mm-hmm. 900 00:47:32,700 --> 00:47:35,866 ♪ ♪ 901 00:47:35,866 --> 00:47:38,266 (whirring) 902 00:47:38,266 --> 00:47:41,266 ♪ ♪ 903 00:47:41,266 --> 00:47:43,033 REIDENBERG: Oh, that's awesome. 904 00:47:43,033 --> 00:47:44,566 MACKAY: That's beautiful-- beautiful. 905 00:47:44,566 --> 00:47:45,833 REIDENBERG: Look at how she's putting 906 00:47:45,833 --> 00:47:47,033 the baby on her, on her... MACKAY: Yep. 907 00:47:47,033 --> 00:47:48,566 She'll scoop under and pick it up. 908 00:47:48,566 --> 00:47:49,900 REIDENBERG: And she's using that, 909 00:47:49,900 --> 00:47:51,766 that flat surface of the top of her head 910 00:47:51,766 --> 00:47:53,033 to hold the calf there, 911 00:47:53,033 --> 00:47:54,933 almost like it's got a cradle surface. 912 00:47:54,933 --> 00:47:56,966 So she can give the calf a rest this way. 913 00:47:56,966 --> 00:47:59,133 Or if she feels like the calf's in danger, 914 00:47:59,133 --> 00:48:01,400 she could pull this calf right up out of the water. 915 00:48:01,400 --> 00:48:04,400 And there's the male. 916 00:48:04,400 --> 00:48:06,933 NARRATOR: This mom is being pursued by a male. 917 00:48:06,933 --> 00:48:10,066 ♪ ♪ 918 00:48:10,066 --> 00:48:12,966 She's putting the calf on her head 919 00:48:12,966 --> 00:48:17,066 to protect it from his aggressive advances. 920 00:48:17,066 --> 00:48:19,500 Mithriel thinks this protective behavior 921 00:48:19,500 --> 00:48:24,433 plays a role in baleen whale survival. 922 00:48:24,433 --> 00:48:26,766 Picture them out, and killer whales coming up 923 00:48:26,766 --> 00:48:28,533 and seeing this baby as a good meal. 924 00:48:28,533 --> 00:48:32,666 The moms that are able to use their flat head 925 00:48:32,666 --> 00:48:35,866 to scoop the baby up out of the water and get away 926 00:48:35,866 --> 00:48:39,433 are the ones whose babies are going to have babies. 927 00:48:39,433 --> 00:48:42,900 We're always taught evolution changes things, 928 00:48:42,900 --> 00:48:44,533 but it doesn't. 929 00:48:44,533 --> 00:48:46,633 What it really does is, it eliminates 930 00:48:46,633 --> 00:48:48,433 the stuff that doesn't work as well, 931 00:48:48,433 --> 00:48:50,800 so what's left is what works. 932 00:48:50,800 --> 00:48:52,966 It's reactive, it's not proactive. Exactly. 933 00:48:54,333 --> 00:48:58,333 NARRATOR: And these whales have one other vital defense mechanism: 934 00:48:58,333 --> 00:49:01,000 their huge size. 935 00:49:01,000 --> 00:49:04,666 How did they get so big? 936 00:49:04,666 --> 00:49:06,966 The ancestors of these whales 937 00:49:06,966 --> 00:49:08,566 were actually smaller than our current whales. 938 00:49:08,566 --> 00:49:10,500 That made them more nimble. 939 00:49:10,500 --> 00:49:11,800 They could swim through the water 940 00:49:11,800 --> 00:49:13,100 more agilely, picking out fish. 941 00:49:13,100 --> 00:49:15,833 But when we look at these large baleen whales, 942 00:49:15,833 --> 00:49:18,600 they are feeding in a completely different way, 943 00:49:18,600 --> 00:49:21,133 and that is partly what's allowed them to get so big. 944 00:49:21,133 --> 00:49:24,333 So, having large bodies means they have large mouths, 945 00:49:24,333 --> 00:49:27,033 and the large mouths allowed them to get a lot of prey. 946 00:49:27,033 --> 00:49:29,400 And having a large body also allows them 947 00:49:29,400 --> 00:49:30,633 to carry a lot of fat reserves, 948 00:49:30,633 --> 00:49:33,066 which they are using for swimming 949 00:49:33,066 --> 00:49:34,600 to the regions where the prey are. 950 00:49:36,300 --> 00:49:38,366 But having that absolute big size 951 00:49:38,366 --> 00:49:42,533 is something that really evolves because they're in water. 952 00:49:42,533 --> 00:49:44,400 You know, that biomass 953 00:49:44,400 --> 00:49:46,233 would be very hard to support on the land. 954 00:49:46,233 --> 00:49:47,700 They would just be crushed. 955 00:49:47,700 --> 00:49:51,033 ♪ ♪ 956 00:49:51,033 --> 00:49:52,500 NARRATOR: The whale's transition 957 00:49:52,500 --> 00:49:56,000 from four-legged land mammal to the giant of the oceans 958 00:49:56,000 --> 00:49:58,966 is one of the most extraordinary stories 959 00:49:58,966 --> 00:50:01,233 in the history of evolution. 960 00:50:01,233 --> 00:50:03,600 ♪ ♪ 961 00:50:03,600 --> 00:50:07,333 GINGERICH: Has the mystery of whale evolution been solved? 962 00:50:07,333 --> 00:50:09,700 To some degree. 963 00:50:09,700 --> 00:50:13,366 But when we fill a gap, we make two more, and so, 964 00:50:13,366 --> 00:50:16,166 we're always going to want to know more. 965 00:50:17,600 --> 00:50:19,900 NARRATOR: From the first wolf-sized creatures 966 00:50:19,900 --> 00:50:21,933 that ventured into freshwater rivers, 967 00:50:21,933 --> 00:50:26,566 to the walking whales that were champion swimmers, 968 00:50:26,566 --> 00:50:29,100 to fearsome marine predators, 969 00:50:29,100 --> 00:50:34,566 to the largest animal that has ever lived. 970 00:50:34,566 --> 00:50:36,833 ♪ ♪ 971 00:50:36,833 --> 00:50:39,566 Today, scientists continue to search 972 00:50:39,566 --> 00:50:44,100 for the missing chapters in the whale's story. 973 00:50:44,100 --> 00:50:46,700 SALLAM: There is more to find in Wadi Hitan. 974 00:50:46,700 --> 00:50:51,766 There are so many fossils still hidden inside the rocks, 975 00:50:51,766 --> 00:50:55,166 and we hoping someday to find 976 00:50:55,166 --> 00:50:57,333 very primitive whale 977 00:50:57,333 --> 00:51:00,233 in very ancient deposits 978 00:51:00,233 --> 00:51:03,966 that can actually complete the story 979 00:51:03,966 --> 00:51:05,700 in whale evolution. 980 00:51:05,700 --> 00:51:08,000 That will be a really huge discovery. 981 00:51:08,000 --> 00:51:10,766 ♪ ♪ 982 00:51:10,766 --> 00:51:14,433 NARRATOR: The whale's evolutionary journey is not over. 983 00:51:14,433 --> 00:51:17,533 Today, they must survive new threats 984 00:51:17,533 --> 00:51:21,400 that are driving some species close to extinction. 985 00:51:23,566 --> 00:51:24,933 REIDENBERG: There are a lot of new challenges 986 00:51:24,933 --> 00:51:26,366 that the whales are facing today, 987 00:51:26,366 --> 00:51:29,333 whether it's fishing, ship traffic, noise, 988 00:51:29,333 --> 00:51:32,200 climate change-- anything could be a factor, 989 00:51:32,200 --> 00:51:33,866 because if it affects their habitat, 990 00:51:33,866 --> 00:51:35,366 it affects their evolution. 991 00:51:35,366 --> 00:51:36,500 Exactly. 992 00:51:36,500 --> 00:51:38,466 And the challenge is, 993 00:51:38,466 --> 00:51:40,233 evolution doesn't happen overnight, 994 00:51:40,233 --> 00:51:42,066 so we don't really know 995 00:51:42,066 --> 00:51:44,533 what the consequences of that will be. 996 00:51:44,533 --> 00:51:46,066 ♪ ♪ 997 00:51:46,066 --> 00:51:49,433 NARRATOR: Whales face a precarious future. 998 00:51:49,433 --> 00:51:52,600 The hope is that they will adapt and survive 999 00:51:52,600 --> 00:51:56,366 as they have done for 50 million years. 1000 00:51:56,366 --> 00:52:02,233 ♪ ♪ 1001 00:52:05,466 --> 00:52:09,466 ♪ ♪ 1002 00:52:17,066 --> 00:52:24,600 ♪ ♪ 1003 00:52:28,433 --> 00:52:35,966 ♪ ♪ 1004 00:52:37,600 --> 00:52:45,133 ♪ ♪ 1005 00:52:46,766 --> 00:52:54,300 ♪ ♪ 1006 00:53:00,100 --> 00:53:07,266 ♪ ♪