How the T-Rex Lost Its Arms
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- čas přidán 25. 06. 2018
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Tyrannosaurus rex was big, Tyrannosaurus rex was vicious, and Tyrannosaurus rex had tiny arms. The story of how T-Rex lost its arms is, itself, pretty simple. But the story of why it kept those little limbs, and how it used them? Well, that’s a little more complicated.
Thanks as always to Nobumichi Tamura for allowing us to use his wonderful paleoart: spinops.blogspot.com/
Produced for PBS Digital Studios.
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References:
Baron, Matthew G., David B. Norman, and Paul M. Barrett. "A new hypothesis of dinosaur relationships and early dinosaur evolution." Nature 543.7646 (2017): 501.
Bates, Karl T., and Peter L. Falkingham. "Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics." Biology Letters (2012): rsbl20120056.
Brusatte, Stephen L., and Thomas D. Carr. "The phylogeny and evolutionary history of tyrannosauroid dinosaurs." Scientific Reports 6 (2016): 20252.
Burch, Sara. Osteological, Myological, and Phylogenetic Trends of Forelimb Reduction in Nonavian Theropod Dinosaurs. Diss. The Graduate School, Stony Brook University: Stony Brook, NY., 2015.
Carpenter, Kenneth. "Forelimb biomechanics of nonavian theropod dinosaurs in predation." Senckenbergiana lethaea 82.1 (2002): 59-75.
Erickson, Gregory M., et al. "Bite-force estimation for Tyrannosaurus rex from tooth-marked bones." Nature 382.6593 (1996): 706.
Fowler, Denver W., et al. "Reanalysis of “Raptorex kriegsteini”: a juvenile tyrannosaurid dinosaur from Mongolia." PLoS One 6.6 (2011): e21376.
Gillingham, James C., and Jeffrey A. Chambers. "Courtship and pelvic spur use in the Burmese python, Python molurus bivittatus." Copeia 1982.1 (1982): 193-196.
Gould, Stephen Jay, and Richard C. Lewontin. "The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme." Proc. R. Soc. Lond. B 205.1161 (1979): 581-598.
Hutchinson, John R., and Stephen M. Gatesy. "Dinosaur locomotion: beyond the bones." Nature 440.7082 (2006): 292.
Makovicky, Peter J. "A new small theropod from the Morrison Formation of Como Bluff, Wyoming." Journal of Vertebrate Paleontology 17.4 (1997): 755-757.
MIDDLETON, KEVIN M., and STEPHEN M. GATESY. "Theropod forelimb design and evolution." Zoological Journal of the Linnean Society 128.2 (2000): 149-187.
Personal communication, Amy Atwater & Dr. John Scanella, Museum of the Rockies
Pontzer, Herman, et al. "Control and function of arm swing in human walking and running." Journal of Experimental Biology 212.4 (2009): 523-534.
Ruiz, Javier, et al. "The hand structure of Carnotaurus sastrei (Theropoda, Abelisauridae): implications for hand diversity and evolution in abelisaurids." Palaeontology 54.6 (2011): 1271-1277.
Sellers, William I., et al. "Investigating the running abilities of Tyrannosaurus rex using stress-constrained multibody dynamic analysis." PeerJ 5 (2017): e3420.
Sereno, Paul C., et al. "Tyrannosaurid skeletal design first evolved at small body size." Science 326.5951 (2009): 418-422.
Stanley, Steven M. “Evidence that the Arms of Tyrannosaurus rex were not functionless but adapted for vicious slashing.” Geological Society of America Annual Meeting 2017.
Sullivan, Corwin, et al. "The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs." Proceedings of the Royal Society of London B: Biological Sciences (2010): rspb20092281.
Therrien, François, and Donald M. Henderson. "My theropod is bigger than yours… or not: estimating body size from skull length in theropods." Journal of Vertebrate Paleontology 27.1 (2007): 108-115. [108:MTIBTY]2.0.CO;2
USAMI, Yoshiyuki, and Ryuta KINUGASA. "A Possibility of Fast Running of TYRANNOSAURUS." DEStech Transactions on Engineering and Technology Research amma (2017).
Xu, Xing, et al. "A basal tyrannosauroid dinosaur from the Late Jurassic of China." Nature 439.7077 (2006): 715. - Věda a technologie
Hi, this is Blake, the script editor. The worst thing that I can do at this job is to be wrong. And the second-worst thing is to be unclear. And this episode was both of these things, at least once, which is my fault, and I’m sorry about it.
Because clearly, when it comes to tyrannosaurs, you all have a lot of opinions, and you know a lot about the latest research! But oftentimes, research findings conflict one another, which leads to confusion.
A number of you have left comments pointing out inaccuracies in this episode, and there is one that happened on-set. But most of the other common complaints we've received come down to the sources we used, which may conflict with other findings you might have read about. So here are a few common comments we've received, and our responses to them:
• You said: "Tyrannosauridae is not a superfamily": That is correct. We were not. The script actually had Tyrannosauroidea as the superfamily, but it was mispronounced on set, and then the graphic was changed to suit the mispronunciation. So, that was a double-fail there.
• You said: "Sauropodomorphs like Riojasaurus weren't ancestors of Tyrannosaurus": Tyrannosaurs and prosauropods did share a common ancestor, but the problem here is in how the script was edited. An initial version of this script read, "Early ancestors of T. rex included things like Prosauropods, which had forelimbs just as long as their hindlimbs." But that was shortened in later script versions, which ended up with us oversimplifying the quadrupedal/bipedal changes that occurred in early dinosaurs, as well as the exact nature of the relationship between Prosauropods and Theropods. Riojasaurus itself was simply chosen as an example of what a prosauropod looks like, rather than an exact, direct ancestor. A better way of saying this would be, "Early ancestors of T. rex included things like that looked more like Prosauropods than T. rex, and had long forelimbs."
• You said: "Raptorex is from 90 million years ago, not 125 million": According to Sereno et al 2009 (which describes the type specimen of Raptorex), Raptorex is from 125 million years ago. We used this article for Raptorex's age, though Brusatte & Carr 2016 have a different age assigned to it (~75). FWIW, our writer is not entirely sold on the new proposed date.
• You said: "Raptorex is Tarbosaurus": Brusatte & Carr 2016 accepted Raptorex as a genus. So we did too. When it comes to ontogeny & dinosaurs there is a lot left to be explored, but there are multiple supported opinions on the topic, not one.
• You said: "Raptorex is "a dubious taxon ": Well, it's considered a dubious taxon by some people. We figured since one of the world's experts on Tyrannosaurs (Carr) had described it as Raptorex in the last two years, it was valid.
• You said: "What you described as 90 million years of evolution actually occurred over 15 million": The trend of limb reduction that we describe is not between Raptorex and Tyrannosaurus, but between Guanlong (or a similar organism) and Tyrannosaurus. Raptorex represents a midway step along that path. That, too, was unclear, so I’m sorry about that.
• You said: "I have problems with your estimates for T. rex’s mass [10,000 kilograms] and height [6 metres].": Scientists rarely include height and mass estimates for the creatures they write papers about and instead provide images with scale bars. So we used the image with scale bar from Therrian and Henderson's 2007 paper on mass, put it into ImageJ, and calculated an estimate of between 15 & 20 feet at the head. The estimate of 3.6 meters tall is at the hip. In the image provided by Therrian and Henderson, the dinosaur's head was significantly higher than its hip. The mass estimate is from that paper. Technically, we rounded down from 10,200 kg.
Just to offer some bona fides, this episode was written and fact-checked by working paleontologists (Dr. Meaghan Wetherell and Kallie Moore, respectively), who wrote these clarifications.
Thanks for sticking with us for our first year, and for understanding that sometimes we make mistakes or are unclear.
Now, go back to arguing about feathers. But be nice! (BdeP)
PBS Eons Its nice to see a channel provide info like this when mistakes are made and not just leave their audience misinformed. Thank you!
PBS Eons They were for display. Mating and aggressive displays over rotting carcasses. They had bright vibrant feathers attached to those arms and flapped them. Their bites were too powerful to fight over mates and scavenging.
Don't worry too much. When I was young, official museums and textbooks still showed t-rex walking erect, even though it looked really awkward and counterproductive. (I even had a dream of one that couldn't catch me because its tail kept getting stuck on things.)
I heard that this was eventually corrected at first by accident, when a kinesiologist or physiologist happened to come into a museum to meet a paleontologist friend to go to lunch, and he remarked (approx): "Why do you have it like that? It would have to have its back broken in 2 places to stand up that way." He also noted later: "This is not a creature that can afford to fall down. It would probably crush its own ribcage and never get back up, so running would be dangerous for it. Plus, look at those long thighbones. This thing walked up to its food like a scavenger."
Anyway, when you are working out at the cutting edge of theory like you do, there will always be alternate views and perspectives, and only time will sort them out. Keep up the good work!
Well, you admitted you were wrong, so I'll give you that. It's always nice to see scientists and science writers admit they aren't perfect, because quite frankly not enough do.
They way you described the t-rex losing its arms sounds a lot like Lamarckism.
"T rex what happened to your arms?"
"I skipped arm day bro....For Like a billion years"
Maybe 20 mill
nice
lol😂
Timothy Drake x Coffee other t-Rex flexes. The T. rex who skipped arm day cries
U mean 90 million.
No joke. I live in the USA and went to a Christian school in the early 90s. My science teacher said that T Rex used its little arms to hold onto trees while eating fruit in the garden of eden. It's teeth were cantaloupe slicers! I thought it was funny and told my parents who withdrew me from the school.
Hahaha, wow, how is that even legal?
Trude - Government loves stupid citizens, that's how.
Classic.
@Nobody Knows That's right. It was privately supported with no public funding.
@Nobody Knows Yes, at least it is a funny story now.
“... probably only a little bigger than your own arms”
*q mental images on people arm wrestling with a t-rex*
Haha class, this might be one of the best things I’ve read
It probably would win because of how the biceps alone could bench press 430 lbs. Though T.rex arm wrestling would look different from our arm wrestling, with walls on either side, and the goal being to pin the opponent’s arm against the wall.
...what have you done!!!
well it can still lift a piano with those "weak" arms... But yea that would be funny lmao But imagine arm wrestling with a carnotaurus and somehow losing
My guy your arm would get reduced to powder cause a T-Rex can lift 400 lbs with its tiny arms.
When I was little I thought raptors were the t.rex's little minons and they did the t.rex's biding, and would say
'Yes master'
In dinosaur lol
Writers of "Jurassic world": *Write that down, write that down!*
XD
Res raster
They were an extension of its arms.
Great Imagination
Lol i also used to think that
*"RAAAAWR! I'M SO STRONG*
ᵉˣᶜᵉᵖᵗ ᶠᵒʳ ᵐʸ ˡᶦᵗᵗˡᵉ ʰᵃⁿᵈˢᵎ
*RAAAAAWR!"*
Frank Tiemens
YAASSS Jake Gyllenhaal! 😂
Immature
@@ramy131 *me*
but bigger than yours
"Hold my stronger arm"....
Carnotaurus: Hold my beer
T Rex: Bro... you can´t even hold your beer
Antonio Centeno underrated comment.
Spinosaur- Hold my beer...
T. Rex- You wanna fuken go?!
T-rex: Nope, can't hold beer.
🤣. Thanks for the clever comments and smile
correct because carno had a arm backwards stuck on the sides of the body
3:47: "Who are you?"
3:59: "I'm you, but accurate."
That's actually funny lol
One word (that is short for three):
LOL
Imagine being the most ferocious predator, ruling the land. And then millions of years later this happens: 3:59
what lol
This made my day xD
They'd be pissed
honestly if I was a several ton reptile with limited thought processes and I saw a tiny monkey draped in cotton mocking me I'd probably just eat it
🤣
If I woke up one morning in the Cretaceous period and I saw a T-Rex, I wouldn’t be making jokes about his arms lol
You're right I would've made fun of its jaw
Who knows, you might offend him so badly he leaves you alone, or eats you...
@@Viv1dCS That sounds like a flip of a coin.
Lol when the T. rex sees you he’ll wave 🤣
I'd say you should make jokes about his poor turning radius when running away from him.
The small arms were meant for typing, just in case a Tyrannosaurus could find a job as a programmer when they decide their hunting days are over.
@@fidneusdiller8123 Were they that into polka music?
Goddamn legendary comment inspired me to look for a job online
True
Hahahaha
Their Huge heads would bang the Monitor and the CPU
I appreciate the demonstration of how to do an accurate T-Rex impression. :)
huzzah!! omg i love this!!! thank you!!!
I appreciate the accurate feathered images chosen. That and addressing the issue with depictions that have pronated arms. Really shows the amount of dedication and research that goes into this channel.
unfortunately for them all those are pretty inaccurate now. The Prehistoric Planet Rex is the most accurate design.
They didnt lift
AlternateHistoryHub fancy seing you here.
This is enough proof for me that all the cool kids on CZcams watch PBS Eons.
AlternateHistoryHub Trex skipped arm day
Wow just seen u and tierzoo.
Sure as hell did jaw day tho
The actual reason a t-rex cant give a high five is just because they only had 2 fingers on each hand
And a little third one
@@risingmagpie9199 that looks like it's been fused into the middle one.
Qt_Pieee they didn’t even have hands😂😂
A high five needs 2 fingers.
They can in Roman Numerals.
5:13, mental image of t-rexs frantically waving their arms at each other in a hilarious looking cat fight.
Bowler hat guy:Whats going on, why aren't you seizing the boy?
T-Rex: I have a big head, and little arms, Im just not sure how well this plan was thought through.
- Do you see that deadly asteroid falling, honey?
- Yep, I think we should mate right now for the last time. You know, like they do in disaster soapers, for someone later could figure out the purpose of our front limbs.
Now i know what i will do while a asteroid hits earth.... to show what human thumbs are for... :D
:P
Well we did find a bunch of fossilized mating turtles a few years back. There are some kind of "stealth killers" such as a natural gas emission that can theoretically do the trick.
Prometheus ... Twiddle your thumbs???
But I'm sure there's enough room for both of us on this door.
You do realize most tyrannosauridae didn't die during the extinction event but rather in the millions of years of existence that preceded that, do you?
He's got small arns so he can dual wield his .44 magnums. Trex was a cow boy from the wild west.
Scoped .44 Magnum
Wrist orientation checks out.
Scientific accuracy 💯
Carnotaurus: Allow us to introduce ourselves
Allow me, to tell you to shut up and not copy other comments
@@Xgent allow me to also tell you that I did not copy anyone's comment.
And plus, it was a simple joke you don't have to get so offended by it
@@Xgent r/woosh
@@girltrash.7166 shut up ok thanks
The reason the T Rex had small arms was so that no one could see its hands move when it used the force.
I have nothing to say I just wanted to be the first reply.
dis made me laugh for some odd reason💀.
I love the fact, that i am not the only one, that watches "Star Wars", likes swords and dinosaurs...
@@heretyk_1337 omg i love star wars and this made me laugh so hard when I was on a call and now I'm in trouble
Must be it.
The T-rex arms were used for the slap chest mannerism "me T-rex come at me bro".
Lee YAHwehson xxx
LOL why do I see that happening!!?🤣🤣
Maybe. Camels do that.
I'm loving that the first theory on why T Rex had arms is LITERALLY 'for hugs'
3:10 i just imagine a dino running while swinging both its arms 😂🤣
Attack on titan
@@xupin9783 attack on tyrannosaur
Lmfao 🤣
I adore the (anatomically correct) t-Rex impersonation 😂👍
@@Doki_Dokers I question why you question her knowledge
@@FlorenciaVM1 I question why you question question
@@Andy-kf4ug I question why you question their question of her questioning
I question using the thumb and forefinger unless the T-Rex had two opposable digits. They might evolutionarily be the thumb and forefinger, but a human doing the impression that way is still suggesting opposability. I say it ought to be the index finger and middle finger.
@Elena Lenkova
Girl, are you a paleontologist?
Because then you'd have to date me.
Trex : hold my beer
Me : why
Trex : cos I can't 🥺
RK Vishnu u idiot if a T. rex tells u to hold there beer how would he carry it in the first place and a t.rexs hand is bigger then ur hand and ur head combined
Aww t Rex you can't hold
Ameer Meqbel r/woosh
Then why did he want the beer where he can’t hold it and how can the rex give you beer
Why did this make me kinda sad
I imagine rexes fighting for dominance by leaning up like komodos and holding each other with their arms while they fight only by trying to get their jaw around the snout of the other rex, thus leading to the face biting we see all the time in their skulls. Possibly a way to fight without exposing the neck. Just an idea.
Basically a non-lethal, but still physically wounding dominance display.
4:47 that's really an awesome bit of art.
3:22 The most beautiful thing I have ever seen, a T-Rex with a goatee.
See "Your Dinosaurs Are Wrong".
Do one on Lazarus/Elvis Taxa!
TierZoo fancy seeing you here
Ey tier zoo love your content
The meta was so much cooler before the Cenozoic update
I would love to see how the server would handle an update that brought back these builds. Both with and without modern weapon crafting OP human builds
Love your channel
If they didn't go extinct they probably would have lost their arms eventually.
I think it's similar to how whales still have pelvic bones even though they have no legs to attach to it. And I imagine it takes a long time for evolution to toss out whole bones
How would it just toss out something though? Not like females can see the pelvic bone and make a decision on mating? Forcing one type of whale with pelvic bone to go extinct. Or genetic mutation causing genes to switch off, eradicating the pelvic bone? I just don’t see how you can get rid of legacy parts
Figure of speech
They already said that in the video towards the end lol
But aren’t T. rex arms quite muscular tho, unlike those of Carnotaurus?
I love how this is titled like a legend. You know "How the Bear Lost its Tail" or "How the Kiwi Got its Wings" or something. Very cool.
Everytime people make fun of T. rex for having small arms, Carnotaurus is just sitting there, hold my beer, no really, he's actually asking, he can't
Hold my beer is way too overused...
I just wonder how he even got the beer. his arms don't even point forward.
Frieda Theiling yeah Carnataurus has the most stupidly small arms and it’s funny how people are so stuck on Rex that trying to tell folks that T. rex at least had arms and that there’s another that would make take the title they don’t wanna listen.
Carnotaurus had the smallest arms people you want something to laugh at this Dino was literally a wrist nubb
At least Rex was able to lift 400lbs Carno? Well he could flap like a penguin
T Rex: grab my hand Son!
Baby Rex: I can’t reach!
T rex: NOOOOO!
Baby Rex: HELPPPP!
In case it is not clear the scenery is at a cliff and the baby Rex is falling.
Great job lmao
Small hand
And then grandpa t rex sees all of it and laughs and grandma trex slaps grandpa for laughing and starts to slowly thump away and then returns just to slap baby t rex because she felt like it
We have movie drama we don’t need that
*talks about t-Rex tiny arms*
Carno: *sad dinosaur sounds*
This would’ve been funnier if it was changed to happy dinosaur sounds
I've been watching these videos for about a year now. I think this one was my favorite. When he mentioned "that we just haven't found the right fossils yet"
“Legs and Teeth. THATS ALL WE NEED!”
Taken from the Memoirs of a T Rex.
But... How did it write the memoirs then?
@@davemoyer4159 they dictated them
My elder son is 5 years old, and this kid knows more about dinosaurs than the vast majority of adults.
❤
Of course, Daddy is a massive paleontology nerd.
For anyone wondering, yes the arms were relatively small, but it has been eating today that each arm could lift approximately 500 lbs (226.796 kgs). That is to say, if the fingers were able to hook onto some sort of cord that had weight on it, the T-Rex could hoist up to 500 lbs off the ground.
So when you consider it's got a minimum of a 1,000 lbs of force hold it can do with just those two arms, it becomes quite clear it could absolutely be useful.
One theory I rather enjoy is that the arms were used to assist in lifting it's massive body off the ground when it was waking up from naps. Sort of like a push-up. While this would not lift the whole animal up, it could take the strain off of the legs just enough to assist in standing.
Over millions of years they developed a high level of intelligence. The small 2 fingered arms were used for writing. In this way they could teach their young hunting strategies like a coach would a football team.
precisely
What if this is actually true....
This must be from a hard time research and in deep analysis
@@waterbottle8692 If it was we'd find fossils that show the marks they used to write, their written language. We've found nothing older than human stuff so, yeah. It's not. Evidence is king, baby.
Fandom guy Unless they just wrote in the dirt 🤔
Happy birthday, Eons!
Btw, Hank, your accurate T-Rex impressions made my morning
Hanif Huzairi yessss they actually put feathers on the T-rex😂
The whole feathers thing has no basis in accuracy though.
It has, kind of, as the impressions aren't from the hole body. The reconstruction they showed where majoritary correct as they had scales where they should and feathers in parts that we don't know. Also, keep in mind that we have a tiranosaurid that was presumably fully feathered or al least had a very large feather coat.
Yes! Somewhere around four minutes is the best (and most) Hank.
XD Yea your t-rex was !spot! on XD
Can every science show just have this guy be the main speaker, never fails to get a laugh out of me.
I absolutely love that this channel shows feathered dinosaurs whenever it can when talking about them.
What's the history of metamorphosis? It's such a fascinating and drastic behavior, almost like a single organism performs its own evolution.
Mark O'Meara I 've thought of that too. It does seem like it mirrors evolution. I think it is likely a more complex gestation period. Kind of like how humans come out early and useless because we are still developing.
A better example is frogs. They essentially hatch before they reach a normal birth and keep growing in the same way as if they were in an egg. Following their evolution and what other animals would do while still in the womb or egg.
Mark O'Meara
I wouldn’t say a single orgasm was drastic behaviour just the act of a maybe lonely person, granted orgasms shared are the best but . . . W8. . . Oh crap . . . Organism . . . Ooops laters (much later) . . Doh 🙁
Caterpillars spit all over themselves, turn themselves into goo, and then somehow turns its goo self into a 6 legged thing that flies.
Nature, explain.
It is an interesting question I know part of their rise in prominence was due to the Great Dying erasing much of their competition but I have no idea what they were like before that and their story is also intimately linked to the emergence of insect based pollination
The T-Rex was like "look ma, no hands!"
Lol that was Gold 😂
I’m so glad that someone showed me the correct way to do the T-Rex 🦖 impression lmao, I’ll use this information to make fun of people. I love this 😆🤣🤣🤣🦖🦖🦖🦖
Man, it'd be great just to go back in time to see exactly what dinosaurs looked like, and exactly how they behaved
so you telling me the most vicious predator is also the best hugger of all time? #misunderstood
Shouldn't this comment include #barney?
*NEVER* skip arms day
I saw a video on Because Scince that mentioned that T. Rex's arms could lift 150kg, according to biomechanics studies, if that's true they had kinda strong arms for a skipper.
I see what you did there.
No this is Patrick nice pic
@@rafaelalodio5116 for a bodyweight of 10 tons and accordingly srong legs 150kg is nothing though.
legs are more powerful
I've never come across a channel more interesting than this.
Hank never disappoints.
*If you're happy and you know it clap your...oh*
Emmanuel Alejandro. *Clap your teeth*
Emmanuel Alejandro XD
Emmanuel Alejandro *Clap your tail*
If you actually watched the video clapping your hands is pretty much all they're capable of ;)
Congratulations! You won the internet today! 😂
This is one of the best channels on CZcams!
Great video!
I know right
Agreed
ONE thing I got out of this: 3:42 accurate forearm impressions of the T. Rex.
little really known to have put such an indept thesis for like instance what total range Trexes fossils ever been found & with what other dinosaurs , could one have eaten the front legs from some prey then to have fallen prey themselves then that dinosaur eat theres then moved on ,there was a great migration right?
I vote for TREY the Explainer
Your impressions of how T-Rex held its hands really bring home what they looked like and how they acted. Aww, T-Rex cuddle FTW!
3:59 a genuine, unedited, and left-in-tact laugh from Hank Green. Never seen something like that
Me: Hey T-rex, give me a high five.
T-rex: How about a high two.
Me: that'll do.
Maybe a middle two
Or there goes my hand...
Mononychus: Come on, I'm trying my best here.
"That'll two" you mean?
🖖🏽🖖🏽
Everyone: makes jokes of T. Rex arms.
Carcharodontosaurids, Alvarezesaurids and Abelisaurids: Glad they didn´t notice me.
Abelisaurids had far punier arms than T. rex. Gorgosaurus and Albertosaurus also had smaller arms.
Meanwhile carnotaurs be like:don’t let them find me
@@ColonelSanders493 AKA a head with legs
What about our good pal carnotaurus
Moas: *Sobbing*
Meanwhile in an alternate universe: A T-rex is wondering why prehistoric humans had such a weak bite.
Loved the t Rex arm impression especially
Can you please do a video on the mammals that lived prior to the K-Pg extinction event? It would be interesting to know more about them, usually they are only briefly mentioned in videos as "small shrew like animals that lived in the shadows of the dinosaurs".
Prosauropods weren't the ancestors of Tyrannosaurs. The traditional theory is that indeed they branched off a common ancestor shared with Theropods, but that doesn't really say much.
Tyrannosaurs were more closely related to birds than to Carnosaurs like Allosaurus.
We could look for more fossils, or we could save a lot of time by sequencing it's genome and build a park devoted to them on an island. Now I'm no chaos theory specialist, but I'd say it would be extremely successful
As a person who studies paleontology. I love that the tyrannosaurus is feathered.
They looked woolly to me. Maybe sheep have T-Rex DNA.
When your arms don’t work like they used to before...
and I can't sweep you off of your feet
Why are we still here? Just to suffer? I can feel my legs, my arms, even my fingers...
Will your arms still remember the taste of my love?
Will your eyes still smile from your cheeks?
darling now!..i'm still be loving you, till we're seventy!
The sad music at the end though...
Poor T-Rex.
What's it called?
yes, let us clone som back to life :D
Nekogami-Crystal That's, as of right now, impossible.
💔
He was not poor the era it lived it ruled the whole dinosaur
Love this guys presentation skills, I used crash course biology in college so much
This channel is so remarkable, thank you guys so much
T-Rex is only angry because of lack of hugs.
The teeny arms made it so when they hugged they has to hug extra tight like this
tesseract.ca/images/Art/TrexHug.jpg
Very appropriate with the sad piano music....never forget the dinos sacrifice, Rest in RIP.
Rest in Rest In Peace
lol
I just LOVED the T-Rex imitation. Perfection.
Am genuinely happy that I learned the why behind this mystery that plagued me for years
Glad you are showing the concepts of T. rex with feathers.
Which are obsolete. How dreadful that you are glad about teaching people outdated information.
"But it's wrong!"
No backing evidence for feathery Rex, while there is some for scaly Rex.
The current theory is that later, derived tyrannosaurids probably had feathers. Probably because there's been (so far as I know) no direct evidence of feathers in derived tyrannosaurids like T. rex and is relatives like Albertasaurus and Tarbosaurus. The evidence for feathers have been found in much earlier basal tyrannosaurs and tyrannosauroids like Yutyrannus, Guanlong, and Dilong, with the idea being that certain features, once expressed (in this case feathers), don't go away.
Most tyrannosaurid experts believe that tyrannosaurids like T. rex, if they had feathers, were probably not covered head to toe in feathers. The amount of coverage varies with some thinking they only had feathers along the upper sides of their bodies to something more extensive but with bare patche like an ostrich.
Eh, definitely not obsolete. Yeah, a bunch of news outlets copy/pasted that conclusion around without apparently having read or understood much the recently published paper they're citing.
What we've found is some very small & specific spots on T. rex's body were definitely featherless.
On the surface, that may seem like you should be able to extrapolate that to the entire body and that it would be grasping at straws to still hold on to feathered rex, I understand that.
But here's the thing: even in dinosaurs which we KNOW to be feathered, those same spots along the body were still mostly featherless & scaly.
We already knew that T. rex, whether or not it is otherwise feathered, WOULD likely be scaly in those exact areas, and many reconstructions already took that into account.
In other words: not much has actually changed. Feathered T. rex still valid, except maybe the absolute fluffiest reconstructions.
czcams.com/video/uM5JN__15-g/video.html
3:23 T-Rex with a beard. Okay, i'm sold, feathered dinos are cool.
I enjoyed that one because it looked like he was rocking a mullet. that's my kind of dino.
It's more of a "goatee" than a full on beard tho right?
I just realized I engage myself in some of the strangest conversations sometimes 🤔🤔🤔
1234kalmar i know right
@@AliceInChains. Your self-awareness is hilarious. Def a goatee tho
Making jokes about TRex’s tiny arms
Take a look at carnotaurus
Not as bad Moa though
They're practically armless
6:01 the picture and music make the rex look like your childhood pet portrait
*DUDE!*
My T-Rex Arm impression was actually *ACCURATE!*
*I'm glad!*
👉😎👉
i will be so cool at parties now
Too bad Jurassic park still cant fix their T. rex arms.
Luis Sierra
*I Will Have So Many Friends, Yeah I'm Cool!*
Lloyd Irving
Then it isn't Jurassic Park anymore...
*(And they already have the right digits)*
How about hearing about each presenter's fave dinosaur & why it's their favorite? It'd be awesome to see them geek out / fangirling & teaching us in the process
The scavenger bit always annoys me, and it's usually based on T-Rex's small arms, except that scavengers are usually small, and T-Rex isn't a one-off or a dead-end evolutionary animal, but has an extensive family tree, as mentioned in the video. He also has highly developed olfactory and binocular vision, traits of a hunter. Also, while hyenas can crunch bone as well, most scavengers do fine just stripping meat from carcasses, so T-Rex:s insane bite force would seem like severe overkill if he we solely a scavenger.
The scavenger theory is that way because it fits T-rex' anatomy better. When chasing prey it's large top-heavy body would have been a hinderance. But when it comes to intimidating other predators and getting the most out of a carcass that has already had it's best parts taken it's body is ideal. The long legs would have made it able to traverse long distances and it's strong sense of smell would have helped it find food.
An example of an animal with a very similar body plan is the American short-faced bear of the ice age. Because it's so much more recent we know it was pretty much a specialized scavenger with one of the best senses of smell of any mammal ever, a super efficient walk and an absolutely enormous silluette.
Concept: the T-Rex used their tiny arms to carry designer handbags
Lazy Existentialist ha ha ha lol LMAO 🤣😂🤣😂 lol LMAO
Monster Mcfly That wasn’t very cash money of you
"Others suggest that T-Rexes used their hugging power for hunting..." *sad music begins to play*
*t Rex is not okay-*
Imagine how beautiful the Earth looked back then🤔😍
You’re right all the dead corps how beautiful it is indeed
Oh, yeah! Bloodthirsty carnivores and trampling herbivores that would kill anything that came close! Soooooo beautiful, all of that Dino dung in water sources and bodies everywhere.
And no grass, for it hadn’t evolved yet
@@whatev9477 fyi, the "dino age" is cleaner than the modern age
whatev Oh yeah! What about greenhouse gases, global warming, trash everywhere, buildings everywhere, hunters etc. The earth looked so clean back in the Cretaceous period
I absolutely love this channel. God bless y’all.
I just realized
If they’re arms are as big as ours, but are considered tiny when our are considered just normal size, Tyrannosaurus rex was HUGE
(I dont pay attention to the size descriptions in studies so if that was obvious dont judge me)
Correct.
Hank Green is a fantastic presenter. Love his enthusiasm and ability to explain ideas in an interesting and approachable way! Thanks Hank!
No silly. T-Rex was a cyclist.
Dekiroou normie
Unicyclist. Hence the bigger legs.
But wouldn't a unicyclist T Rex need arms to juggle?
Skipped arm day???
@@bcubed72 bicyclist.
For some reason I just can't wrap my mind around the idea of two T-Rex' mating.
Love this channel!
The game devs had to pre-emptively nerf the rex's range due to it being overpowered in the late cretaceuous patch. Thankfully the nerfs to the trex weren't too harsh and was still viable.
This from the TierZoo channel?
Correcting mistakes I spotted in script:
Hanks calls sauropodorphs "Ancestors of the genus Tyrannosaurus", which they are not. (That whole section is confusing)
Raptorex is a juvenile, adults were larger and with different proportions. (Likely synonym of Zhuchengtyrannus or Tarbosaurus)
Raptorex (70 - 80 mya) is 90, not 25 million years younger than Guanlong (160 mya).
Raptorex shows up 2 - 7 milion years before T.Rex... not 70.
The small arms in tyrannosaurids only appear 15 million years before rex, not a "90 million year old trend"
Note: Raptorex is now thought to not be 125 my old, only around 70 - 80.
(This episode feels rushed, with poor fact checking probably bc of the whole "birthday" thing. :/)
They are well-known facts just look the animals up. I am not trying to spew sht on Eons just correcting unintended misinformation in the comments.
Any citations in the "original presentation"?
Yeah, this is pretty basic stuff. In fact, a new paper would make them even more distant relatives of the prosauropods.
Baron, Matthew G., David B. Norman, and Paul M. Barrett. "A new hypothesis of dinosaur relationships and early dinosaur evolution." Nature 543.7646 (2017): 501.
You can freely check the info that Im providing by typing the animal's name into wikipedia or google. You don't have to trust me. Yes, it's true that raptorex was initially believed to be 125 million years old, but there is no reason to think that and is not the consensus anymore. It was thought to be that old based on misindentified fish remains associated.
Isn't the digit part super simplified too, since the whole I-II-III vs. II-III-IV thing is highly debated?
T-rex: Awww i want a bigger arms
Carnotaurus: You okay, bro?
Humans: Hahahah T-rex has tiny arms
T-Rex: Snaps human in half with one finger.
I have an odd question that I'd like to see examined: how many animals are like humans in that they have brain lateralization in terms of handedness. Humans are a little strange in that we tend to favor one hand or the other for tasks requiring fine motor control, although we can often train both fairly decently. As a left-handed pianist, I'd love to know about what other animals might favor one limb over the other, and whether they might have a common ancestry.
I've heard of cats favoring their right or left paws :)
as well as dogs
(From what I could find)
For cats:
50% Right pawed
40% Left
10% Ambidextrous
For Dogs:
About a 50-50 split for right and left with a very small handful being ambidextrous.
With horses though around 70% are left hoofed while around 20% are right with about 10% being ambidextrous.
You can tell by looking at the musculature of the shoulders:
horsej-intellectsolutio.netdna-ssl.com/cdn/farfuture/t2qU_CBFDjdTO1PGzZNF7AsckCyVfqMfd97vqyy7TZw/mtime:1508957129/files/2017/image_1.jpg
Parrots are left clawed (taloned)
Most sea athropods have this biasness towards their primary limb usage. One of them even converted one of it's arms into a plasma cannon.
My husband and I totally were practicing our accurate t-rex arms during the video.
I assume while you're mating.
@@jeromealday614 lol
As everyone here should've been doing, of course.
K stfu.
the sudden mood change in the music towards the end got me all emotional about T Rex :'(
okay but that piano melody at the end was so beautiful what is it?
I think the music at the end answers everything.. such a beautiful recording of the T Rex playing piano.
Is anyone going to comment about how Hank Green presented this?
Thank you. I was looking for this.
His amusement at the accurate arms had me dying laughing. They cut off his laugh, but there’s just enough of it to be contagious.
Back in high school when I took psychology we watched a series of videos explain how psychology became what it is today and the great man that was part of videos was Hank Green
Explaining
I loved your trex impressions ! I’ve been doing them all wrong !! Lol
Thanks for leaving some references to follow up with in the body of your video. It's appreciated. I think it was in a Scientific American a few years -- or perhaps longer -- back that it was theorized that T. Rex's arms were at least partially used to help the animal get back into standing posture after sleeping. Do you know the source I mean?
“We’d have to find two T. recess preserved ‘in the act’, so to say, and that . . . That would be a remarkable find.”
*Accuracy.*