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  • This episode is brought to you by  the Music for Scientists album,

  • now available on all streaming services.

  • To start listening, check out  the link in the description.

  • [♪ INTRO]

  • Tyrannosaurus rex has been  everyone's favourite dinosaur

  • for more than a hundred years.

  • And a century of study has given us new  insights into what this terrible lizard

  • looked like, and the role it  played in the Cretaceous world.

  • But even though we're learning more all the time,

  • the popular image of T. rex  seems to be stuck in the past.  

  • Now, new techniques and new fossils  are turning our thinking about

  • these fearsome predators on its head.

  • It's time to meet the real T. rex!

  • Skeletons of this gigantic dinosaur were  first discovered back in the early 1900s.

  • The first paleontologists that studied  them saw rows of deadly sharp teeth

  • and long powerful legs, and rightly  concluded that they belonged

  • to a fearsome predator.

  • This dinosaur, Tyrannosaurus rexlived about 68 to 65 million years ago,

  • at the end of the Cretaceous period.

  • It was one of the biggest  land predators of all time.

  • Since then, T. rex has been immortalized in books,

  • films, and cuddly plushiesas the iconic dinosaur.

  • But if you ask anyone to actually  draw a T. rex from memory,

  • they're a big chance that most  will draw it Godzilla-style

  • upright and balanced on its tail,

  • with its little arms tucked  uselessly next to its chest.

  • The first T. rex skeletons were  actually mounted in this way,

  • and nobody questioned it for a long time.

  • But the discovery of new fossils and  a renewal of interest in the 1970s

  • led to a so-called 'dinosaur renaissance',

  • which transformed how we  see these ancient creatures.

  • Scientists reanalyzed the skeleton of T.  rex, and saw that it was much more likely

  • to have a horizontal spine, with its  back flat and its tail in the air.

  • After this, museum skeletons were remounted,

  • illustrations were updated in  science books, and even popular films

  • like Jurassic Park showed T. rex  as an agile, crouching hunter.

  • But studies have shown that  many people still get it wrong.

  • Researchers think that it's because there's  still so much kitschy stuff out there,

  • like cookie cutters and stuffed toysthat have the out-of-date upright posture.

  • Nevertheless, there's been more  than a hundred years of paleontology

  • since T. rex was discovered,

  • and new techniques have taught uslot about what they're really like.

  • For one, it looks like their tiny  arms might not be totally useless.

  • Sure, T. rex does have comically  tiny arms, and for a long time

  • scientists wondered how they  could do much of anything.

  • But paleontologists speaking at  a conference in 2018 presented

  • some evidence that they were more flexible  and useful than previously thought.

  • The researchers used X-ray imagery and  computer models to look at the joints

  • of some of T. rex's modern relatives --  specifically, turkeys and alligators.

  • Their research hasn't been published yetbut they propose that those tiny arms

  • could actually have brought  prey in close for a bite.

  • However, while its arms may have  been better than we imagined,

  • its legs are a bit of a letdown.

  • T. rex's long, sturdy leg bones  have been used in the past to argue

  • that they could run fast, like an ostrich.

  • But because the muscles and tendons  that actually do the running

  • aren't preserved in the fossil recordestimates haven't been very precise.

  • You can't just guess based on  a smaller animal scaled up,

  • because big animals like T. rex put  proportionally way more strain on their bones

  • and muscles, compared to smaller ones.

  • Using different methods, scientists  have suggested top speeds

  • that range from eighteen to more  than seventy kilometers per hour.

  • That's a bit of a mixed bag.

  • A study in 2017 took a new approachcombining biomechanical simulations

  • with measurements of stress on the skeleton.

  • This revealed that if they even tried to run,

  • it would put too much force on their  leg bones, causing them to fracture.

  • So T. rex was probably limited tofast walk, or a birdy sort of jog.

  • Basically, it works out to a maximum  speed of about thirty kilometers per hour.

  • That means an Olympic sprinter  would easily be able to outrun one!

  • Thoughnot for very long.

  • Also it means I definitely couldn't.

  • While new techniques are giving  us insight about old fossils,

  • new fossils are turning up  that change our thinking too.

  • Which brings us to the feather question.

  • In the last few decades, remarkably  preserved fossils are revealing

  • that all kinds of dinosaurs had soft, downy  feathers, including relatives of T. rex.

  • Dilong paradoxus, a small ancestor of T. rex,

  • was discovered to have simple  proto-feathers in 2004.

  • And the nine-meter-long  Yutyrannus, described in 2012,

  • is the largest feathered dinosaur discovered yet.

  • It was previously thought that only  the smaller dinosaurs had feathers,

  • because small bodies tend to need  more insulation than big ones.

  • But huge fluffy Yutyrannus made us think again.

  • Soon, the idea of feathered bodies  expanded to include all tyrannosaurs,

  • including T. rex, because  scientists think a trait like that

  • isn't easily lost by evolution.

  • But a study in 2017 analysed  brand new fossils of T. rex skin,

  • which were scaly, not feathered.

  • These two conflicting points of view  have sparked intense debate among

  • paleontologists, intense enough thatlike, we don't want to get into it

  • But this is definitely a mystery  we won't be able to solve for sure

  • until we have more fossils.

  • We don't know for sure, but  it's possible that baby T. rex

  • may have been born fluffy, with  insulating feathers over their bodies.

  • Adults could have retained a few  feathery bits here and there,

  • but the matter is far from settled.

  • In a way, though, that's exciting.

  • It shows how much there still is to learn  even about something we think we know well

  • like this familiar staple of  every six-year-old's toy chest.

  • Who knows what we'll learn  in the next hundred years?

  • In retrospect, it's easy to poke fun at those old,

  • incorrect museum mounts of  T. rex and other dinosaurs.

  • But science is a process of sifting through ideas

  • and discarding the ones that  don't hold up to experimentation.

  • These ideas, right and wrongare celebrated in the song

  • The Idea from the album Music for Scientists.

  • The song also has an original music  video that fuses original artwork

  • and machine learning -- just  like the whole album ponders

  • the intersection of art and science.

  • If that sounds like it might be your jam,

  • you can start listening to Music for  Scientists at the link in the description.

  • [♪ OUTRO]

This episode is brought to you by  the Music for Scientists album,

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Meet the Real Tyrannosaurus rex

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    joey joey に公開 2021 年 05 月 13 日
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