1 00:00:02,040 --> 00:00:06,920 Speaker 1: Welcome to brain stuff from how stuff works. Hey, they're 2 00:00:06,960 --> 00:00:10,319 Speaker 1: brain stuff, Lauren bobil bomb here. Flight is a hard 3 00:00:10,360 --> 00:00:14,080 Speaker 1: thing to master. The vast majority of vertebrates can walk, swim, 4 00:00:14,200 --> 00:00:16,440 Speaker 1: or do both, but in the history of life on 5 00:00:16,480 --> 00:00:19,680 Speaker 1: this planet, only three groups of backboned animals have ever 6 00:00:19,760 --> 00:00:23,239 Speaker 1: evolved the ability to fly. Early bats acquired the skill 7 00:00:23,360 --> 00:00:26,560 Speaker 1: roughly fifty two million years ago. Feathered dinosaurs began to 8 00:00:26,600 --> 00:00:30,040 Speaker 1: experiment with flight back in the Jurassic period. Incidentally, you 9 00:00:30,080 --> 00:00:33,800 Speaker 1: probably know of their descendants today as birds. Yet while 10 00:00:33,880 --> 00:00:36,400 Speaker 1: birds and bats are still around, the animals that first 11 00:00:36,479 --> 00:00:40,320 Speaker 1: pioneered vertebrate flight are long gone. That's because two hundred 12 00:00:40,320 --> 00:00:43,279 Speaker 1: and twenty eight million years ago, a flying plade of 13 00:00:43,360 --> 00:00:48,160 Speaker 1: reptiles evolved. These were the pterosaurs. Though Hollywood often mislabels 14 00:00:48,159 --> 00:00:51,880 Speaker 1: them as dinosaurs, they actually represented a separate, contemporaneous group. 15 00:00:52,720 --> 00:00:55,320 Speaker 1: For more than a hundred and sixty million years, dinosaurs 16 00:00:55,320 --> 00:00:58,320 Speaker 1: and pterosaurs lived side by side. It was an exciting 17 00:00:58,360 --> 00:01:01,320 Speaker 1: time to be an aeronaut. During their reign, the pterosaurs 18 00:01:01,400 --> 00:01:05,560 Speaker 1: diversified like crazy. Some species would be comparable to sparrows 19 00:01:05,560 --> 00:01:08,680 Speaker 1: in size. Others had wingspans of thirty six feet that's 20 00:01:08,680 --> 00:01:11,840 Speaker 1: eleven meters or more, making them the largest flying animals 21 00:01:11,840 --> 00:01:15,039 Speaker 1: of all time. Then, sixty six million years ago, the 22 00:01:15,080 --> 00:01:18,200 Speaker 1: pterosaurs succumbed to the same mass extinction that wiped out 23 00:01:18,240 --> 00:01:22,560 Speaker 1: all non avian dinosaurs. In seventeen eighty four, Italian naturalist 24 00:01:22,600 --> 00:01:25,199 Speaker 1: Cosmo Collini became the first person to write a formal 25 00:01:25,280 --> 00:01:28,920 Speaker 1: scientific description of a pterosaur skeleton. At the time, he 26 00:01:29,000 --> 00:01:31,400 Speaker 1: thought this strange looking animal was some kind of deep 27 00:01:31,440 --> 00:01:35,000 Speaker 1: sea creature. But thanks to hard working paleontologists, we've learned 28 00:01:35,040 --> 00:01:38,200 Speaker 1: a great deal about these winged wonders. Nonetheless, there are 29 00:01:38,200 --> 00:01:41,520 Speaker 1: still some large gaps in our knowledge. One big mystery 30 00:01:41,560 --> 00:01:45,080 Speaker 1: involves the early lives of young pterosaurs. The first confirmed 31 00:01:45,200 --> 00:01:48,760 Speaker 1: dinosaur nest was unearthed in ninety three. Since then, fossil 32 00:01:48,800 --> 00:01:51,720 Speaker 1: hunters have excavated thousands of dino exit sites all over 33 00:01:51,720 --> 00:01:56,040 Speaker 1: the world. Yet pterosaur eggs are considerably rarer. None whatsoever 34 00:01:56,040 --> 00:01:58,920 Speaker 1: were discovered until two thousand four, when two appeared in 35 00:01:59,000 --> 00:02:02,279 Speaker 1: China and a third showed up in Argentina. In eleven, 36 00:02:02,480 --> 00:02:04,600 Speaker 1: a fourth egg was found next to the skeleton of 37 00:02:04,600 --> 00:02:07,280 Speaker 1: its presumed mother, an adult animal from the genus Darwin, 38 00:02:07,360 --> 00:02:11,000 Speaker 1: a terrorist three years later, and another Argentinian egg emerged, 39 00:02:11,040 --> 00:02:15,079 Speaker 1: along with five additional Chinese specimens. So until very recently, 40 00:02:15,200 --> 00:02:18,280 Speaker 1: the global scientific community hadn't found enough terrasaur eggs to 41 00:02:18,320 --> 00:02:22,440 Speaker 1: fill a standard egg carton, but paleontologists just hit the motherload. 42 00:02:22,800 --> 00:02:25,799 Speaker 1: In the December seventeen issue of the journal Science, a 43 00:02:25,919 --> 00:02:28,680 Speaker 1: Chinese research team announced the discovery of a new site 44 00:02:28,680 --> 00:02:31,680 Speaker 1: in China's Gobi Desert containing at least two hundred and 45 00:02:31,720 --> 00:02:36,120 Speaker 1: fifteen pterosaur eggs. Sixteen preserved embryos were found there as well, 46 00:02:36,320 --> 00:02:40,040 Speaker 1: along with some skeletons from hatchling, juvenile, and adult pterosaurs. 47 00:02:40,680 --> 00:02:43,119 Speaker 1: These eggs are roughly a hundred and twenty million years 48 00:02:43,160 --> 00:02:47,320 Speaker 1: old and were laid by Hammatteris tiensnsis a crusted toothy 49 00:02:47,400 --> 00:02:50,399 Speaker 1: species with an eleven foot wingspan that's about three point 50 00:02:50,440 --> 00:02:54,000 Speaker 1: three meters. Terrastaur experts are still trying to assess where 51 00:02:54,000 --> 00:02:56,960 Speaker 1: it belongs on the family tree. One such authority is 52 00:02:57,000 --> 00:03:00,080 Speaker 1: paleontologist David Hone, who told us in an email that 53 00:03:00,160 --> 00:03:03,880 Speaker 1: Hama RAS's closest relatives were most likely various groups of 54 00:03:03,960 --> 00:03:07,200 Speaker 1: terrasaurs known for being ocean going or at least coastal 55 00:03:07,240 --> 00:03:10,240 Speaker 1: foragers in terms of lifestyle, He says that these animals 56 00:03:10,240 --> 00:03:14,520 Speaker 1: would have behaved like today's gulls and albatrosses. The newfound 57 00:03:14,520 --> 00:03:16,960 Speaker 1: bounty of eggs was recovered by a team representing the 58 00:03:17,000 --> 00:03:20,400 Speaker 1: Beijing based Chinese Academy of Sciences. Most of the shelled 59 00:03:20,400 --> 00:03:22,840 Speaker 1: treasures were embedded in a sandstone block that may be 60 00:03:22,960 --> 00:03:25,240 Speaker 1: hiding even more clutches that have yet to be revealed. 61 00:03:25,919 --> 00:03:28,200 Speaker 1: One reason why this find is so spectacular has to 62 00:03:28,240 --> 00:03:31,960 Speaker 1: do with the fragility of terrasaur egg shells. Like modern chickens, 63 00:03:32,080 --> 00:03:35,800 Speaker 1: extinct dinosaurs laid hard shelled eggs. Contrast these with the 64 00:03:35,800 --> 00:03:39,240 Speaker 1: eggs of present day snakes, whose shells are thin, soft, pliable, 65 00:03:39,400 --> 00:03:42,880 Speaker 1: and have the texture of old parchment. Terrasaur eggs resembled 66 00:03:42,880 --> 00:03:46,600 Speaker 1: the ladder, a fact confirmed by previous discoveries. Because their 67 00:03:46,600 --> 00:03:49,000 Speaker 1: shells were so soft, these rare eggs tend to get 68 00:03:49,160 --> 00:03:52,160 Speaker 1: squitched flat by the forces of fossilization. Yet the ones 69 00:03:52,200 --> 00:03:54,800 Speaker 1: that this new Chinese site were preserved in three dimensions. 70 00:03:55,480 --> 00:03:59,480 Speaker 1: The discovery's implications are still open to debate. Chinese Academy 71 00:03:59,480 --> 00:04:03,240 Speaker 1: of Sciences paleontologist Shallon Wang was the lead author of 72 00:04:03,280 --> 00:04:06,040 Speaker 1: the paper in the journal Science, which announced this big find. 73 00:04:06,360 --> 00:04:08,680 Speaker 1: In it, he and his co authors suggest the site 74 00:04:08,800 --> 00:04:11,920 Speaker 1: may have a lot to say about terrasaur parenting. As 75 00:04:11,920 --> 00:04:14,480 Speaker 1: Whanging and his colleagues point out, some of the embryo's 76 00:04:14,520 --> 00:04:18,839 Speaker 1: lack teeth and their wingbones seem underdeveloped. The paleontologists think 77 00:04:18,920 --> 00:04:21,960 Speaker 1: this could mean that newly hatched Hamma terrists could neither 78 00:04:22,000 --> 00:04:25,000 Speaker 1: fly nor eat solid food. Thus they would have had 79 00:04:25,040 --> 00:04:28,800 Speaker 1: to depend on their parents for protection and sustenance. Other 80 00:04:28,800 --> 00:04:32,279 Speaker 1: scientists have disagreed with that conclusion. In present day reptiles, 81 00:04:32,320 --> 00:04:35,200 Speaker 1: teeth are one of the last things embryos developed, so 82 00:04:35,400 --> 00:04:38,359 Speaker 1: while these developing pterosaurs were toothless, they might still have 83 00:04:38,400 --> 00:04:42,440 Speaker 1: grown some choppers before hatching. Also, according to Michael Habib, 84 00:04:42,600 --> 00:04:45,760 Speaker 1: a pterosaur specialist at the University of California, the fetal 85 00:04:45,800 --> 00:04:48,760 Speaker 1: wings appeared quite robust, meaning the newborns might have been 86 00:04:48,760 --> 00:04:51,920 Speaker 1: able to start flying right away. A point of consensus 87 00:04:51,920 --> 00:04:55,760 Speaker 1: among paleontologists, though, is that pterosaurs probably didn't brood their 88 00:04:55,760 --> 00:04:58,520 Speaker 1: eggs like present day birds. For one thing, as Hone 89 00:04:58,560 --> 00:05:01,200 Speaker 1: told us, the extinct reptile simply could not sit like 90 00:05:01,279 --> 00:05:05,280 Speaker 1: birds due to the anatomical differences. Also, While terrasaurs were 91 00:05:05,279 --> 00:05:08,840 Speaker 1: coated with fuzzy stuff, they lacked feathers, which roosting avians 92 00:05:08,960 --> 00:05:12,320 Speaker 1: used to keep their clutches nice and warm. Another leading 93 00:05:12,360 --> 00:05:15,880 Speaker 1: expert in modern terrasaur science, one S. Christopher Bennett of 94 00:05:15,960 --> 00:05:20,000 Speaker 1: Fort Hayes State University in Kansas, agrees. He said via email, 95 00:05:20,320 --> 00:05:23,000 Speaker 1: there's no evidence and no reason to think that pterosaurs 96 00:05:23,040 --> 00:05:27,200 Speaker 1: incubated their eggs, or rather, they probably deposited them in sands, soils, 97 00:05:27,279 --> 00:05:31,279 Speaker 1: or vegetable matter like modern reptiles. In the past, Bennett 98 00:05:31,320 --> 00:05:34,280 Speaker 1: has championed the idea that at least some terrasaurs formed 99 00:05:34,360 --> 00:05:37,760 Speaker 1: nesting groups near environments suitable for the hatchlings to feed 100 00:05:37,760 --> 00:05:41,200 Speaker 1: and grow safely. He feels the new Hemiiturus site may 101 00:05:41,279 --> 00:05:44,040 Speaker 1: lend some credence to that notion, a sentiment shared by 102 00:05:44,080 --> 00:05:47,440 Speaker 1: Weighing and his co authors. Bennett added careful excavation of 103 00:05:47,600 --> 00:05:50,800 Speaker 1: terrasaur egg deposits could certainly provide evidence as to whether 104 00:05:50,839 --> 00:05:54,920 Speaker 1: eggs were buried and whether terrasaurs reused nesting sites year 105 00:05:54,920 --> 00:06:03,279 Speaker 1: after year. Today's episode was written by Mark Vancini and 106 00:06:03,320 --> 00:06:05,960 Speaker 1: produced by Tristan McNeil. For more in this and lots 107 00:06:06,000 --> 00:06:09,119 Speaker 1: of other thunders topics, visit our home planet, how stuff 108 00:06:09,120 --> 00:06:21,160 Speaker 1: works dot com.