Speaker 1: Welcome to brain stuff from how stuff works. Hey, they're
Speaker 1: brain stuff, Lauren bobil bomb here. Flight is a hard
Speaker 1: thing to master. The vast majority of vertebrates can walk, swim,
Speaker 1: or do both, but in the history of life on
Speaker 1: this planet, only three groups of backboned animals have ever
Speaker 1: evolved the ability to fly. Early bats acquired the skill
Speaker 1: roughly fifty two million years ago. Feathered dinosaurs began to
Speaker 1: experiment with flight back in the Jurassic period. Incidentally, you
Speaker 1: probably know of their descendants today as birds. Yet while
Speaker 1: birds and bats are still around, the animals that first
Speaker 1: pioneered vertebrate flight are long gone. That's because two hundred
Speaker 1: and twenty eight million years ago, a flying plade of
Speaker 1: reptiles evolved. These were the pterosaurs. Though Hollywood often mislabels
Speaker 1: them as dinosaurs, they actually represented a separate, contemporaneous group.
Speaker 1: For more than a hundred and sixty million years, dinosaurs
Speaker 1: and pterosaurs lived side by side. It was an exciting
Speaker 1: time to be an aeronaut. During their reign, the pterosaurs
Speaker 1: diversified like crazy. Some species would be comparable to sparrows
Speaker 1: in size. Others had wingspans of thirty six feet that's
Speaker 1: eleven meters or more, making them the largest flying animals
Speaker 1: of all time. Then, sixty six million years ago, the
Speaker 1: pterosaurs succumbed to the same mass extinction that wiped out
Speaker 1: all non avian dinosaurs. In seventeen eighty four, Italian naturalist
Speaker 1: Cosmo Collini became the first person to write a formal
Speaker 1: scientific description of a pterosaur skeleton. At the time, he
Speaker 1: thought this strange looking animal was some kind of deep
Speaker 1: sea creature. But thanks to hard working paleontologists, we've learned
Speaker 1: a great deal about these winged wonders. Nonetheless, there are
Speaker 1: still some large gaps in our knowledge. One big mystery
Speaker 1: involves the early lives of young pterosaurs. The first confirmed
Speaker 1: dinosaur nest was unearthed in ninety three. Since then, fossil
Speaker 1: hunters have excavated thousands of dino exit sites all over
Speaker 1: the world. Yet pterosaur eggs are considerably rarer. None whatsoever
Speaker 1: were discovered until two thousand four, when two appeared in
Speaker 1: China and a third showed up in Argentina. In eleven,
Speaker 1: a fourth egg was found next to the skeleton of
Speaker 1: its presumed mother, an adult animal from the genus Darwin,
Speaker 1: a terrorist three years later, and another Argentinian egg emerged,
Speaker 1: along with five additional Chinese specimens. So until very recently,
Speaker 1: the global scientific community hadn't found enough terrasaur eggs to
Speaker 1: fill a standard egg carton, but paleontologists just hit the motherload.
Speaker 1: In the December seventeen issue of the journal Science, a
Speaker 1: Chinese research team announced the discovery of a new site
Speaker 1: in China's Gobi Desert containing at least two hundred and
Speaker 1: fifteen pterosaur eggs. Sixteen preserved embryos were found there as well,
Speaker 1: along with some skeletons from hatchling, juvenile, and adult pterosaurs.
Speaker 1: These eggs are roughly a hundred and twenty million years
Speaker 1: old and were laid by Hammatteris tiensnsis a crusted toothy
Speaker 1: species with an eleven foot wingspan that's about three point
Speaker 1: three meters. Terrastaur experts are still trying to assess where
Speaker 1: it belongs on the family tree. One such authority is
Speaker 1: paleontologist David Hone, who told us in an email that
Speaker 1: Hama RAS's closest relatives were most likely various groups of
Speaker 1: terrasaurs known for being ocean going or at least coastal
Speaker 1: foragers in terms of lifestyle, He says that these animals
Speaker 1: would have behaved like today's gulls and albatrosses. The newfound
Speaker 1: bounty of eggs was recovered by a team representing the
Speaker 1: Beijing based Chinese Academy of Sciences. Most of the shelled
Speaker 1: treasures were embedded in a sandstone block that may be
Speaker 1: hiding even more clutches that have yet to be revealed.
Speaker 1: One reason why this find is so spectacular has to
Speaker 1: do with the fragility of terrasaur egg shells. Like modern chickens,
Speaker 1: extinct dinosaurs laid hard shelled eggs. Contrast these with the
Speaker 1: eggs of present day snakes, whose shells are thin, soft, pliable,
Speaker 1: and have the texture of old parchment. Terrasaur eggs resembled
Speaker 1: the ladder, a fact confirmed by previous discoveries. Because their
Speaker 1: shells were so soft, these rare eggs tend to get
Speaker 1: squitched flat by the forces of fossilization. Yet the ones
Speaker 1: that this new Chinese site were preserved in three dimensions.
Speaker 1: The discovery's implications are still open to debate. Chinese Academy
Speaker 1: of Sciences paleontologist Shallon Wang was the lead author of
Speaker 1: the paper in the journal Science, which announced this big find.
Speaker 1: In it, he and his co authors suggest the site
Speaker 1: may have a lot to say about terrasaur parenting. As
Speaker 1: Whanging and his colleagues point out, some of the embryo's
Speaker 1: lack teeth and their wingbones seem underdeveloped. The paleontologists think
Speaker 1: this could mean that newly hatched Hamma terrists could neither
Speaker 1: fly nor eat solid food. Thus they would have had
Speaker 1: to depend on their parents for protection and sustenance. Other
Speaker 1: scientists have disagreed with that conclusion. In present day reptiles,
Speaker 1: teeth are one of the last things embryos developed, so
Speaker 1: while these developing pterosaurs were toothless, they might still have
Speaker 1: grown some choppers before hatching. Also, according to Michael Habib,
Speaker 1: a pterosaur specialist at the University of California, the fetal
Speaker 1: wings appeared quite robust, meaning the newborns might have been
Speaker 1: able to start flying right away. A point of consensus
Speaker 1: among paleontologists, though, is that pterosaurs probably didn't brood their
Speaker 1: eggs like present day birds. For one thing, as Hone
Speaker 1: told us, the extinct reptile simply could not sit like
Speaker 1: birds due to the anatomical differences. Also, While terrasaurs were
Speaker 1: coated with fuzzy stuff, they lacked feathers, which roosting avians
Speaker 1: used to keep their clutches nice and warm. Another leading
Speaker 1: expert in modern terrasaur science, one S. Christopher Bennett of
Speaker 1: Fort Hayes State University in Kansas, agrees. He said via email,
Speaker 1: there's no evidence and no reason to think that pterosaurs
Speaker 1: incubated their eggs, or rather, they probably deposited them in sands, soils,
Speaker 1: or vegetable matter like modern reptiles. In the past, Bennett
Speaker 1: has championed the idea that at least some terrasaurs formed
Speaker 1: nesting groups near environments suitable for the hatchlings to feed
Speaker 1: and grow safely. He feels the new Hemiiturus site may
Speaker 1: lend some credence to that notion, a sentiment shared by
Speaker 1: Weighing and his co authors. Bennett added careful excavation of
Speaker 1: terrasaur egg deposits could certainly provide evidence as to whether
Speaker 1: eggs were buried and whether terrasaurs reused nesting sites year
Speaker 1: after year. Today's episode was written by Mark Vancini and
Speaker 1: produced by Tristan McNeil. For more in this and lots
Speaker 1: of other thunders topics, visit our home planet, how stuff
Speaker 1: works dot com.