7 Dinosaur Mysteries We Haven't Fully Figured Out

[@JimFortune]

In archaeology, if you don't know what it is, it's an object of worship. In paleontology, if you don't know what it is, it's a sexual display.

[@Gew219]

This is so true.

[@MrFreakHeavy]

Or thermoregulation, that's a classic too!

[@RIXRADvidz]

makes you laugh to think what the ''-ologists'' of the future will interpret our little icons and middens , what will they call our civilization? KerPlunkia? Ass-lantis?

[@katiekane5247]

Spoken like a professor!

[@NotHPotter]

With the major metropolitan cities of Peachopia and Eggplantropolis.

[@thekarategirl5787]

Is "possibly attractive to mates" the paleontologist version of "possibly has ritualistic significance" that archeologists use?

[@prdamico]

lol, yup

[@imperium2na]

+

[@NotHPotter]

Lol, good call.

[@IcestormTundra]

Yeah, essentially.

[@gor5048]

Mhm

[@pandoradoggle]

"We can't just reanimate those rocks..." Yeah, not with that attitude. HANK.

[@Pyrochazm]

We need to get the Nomad of Nowhere over here!

[@triciacarey2288]

DNA doesn't last long enough to use fossils or blood thats been preserved.

[@pampatterson5919]

That is hilarious. I cannot believe that joke literally went over people's heads whom are trying to pretend to be smart. Think their "funny bone" just does not dig it.

[@GeekedOutNeckbeard]

They did it Pokémon we can do it in real life damn it! I WILL HAVE MY REAL LIFE KABUTO.

[@anarchyantz1564]

Yeah Hank that is quitting talk!

[@wildraconteuse2272]

Stegosaurus - When my eldest son, now 30, was 6 this was his favorite dinosaur. He told me that he thought the plates were like leaves and that the Stegosaurus probably could convert sunlight into food like plants because he thought the stegosaurus' heads were too small to get enough calories through eating. I thought it was as good a hypothesis as any.

[@avischiffmann6220]

Cute

[@theta6802]

That's an awesome thought process for a kid! May I ask what he does for work now?

[@wildraconteuse2272]

@@theta6802 He is 32 and a lawyer in DC.

[@ii-banned-ii273]

plopp

[@tacticooltroopers6567]

I like that theory but I think it is used to defend against flying predators

[@organicleaf]

Me: curious about dino mysteries SciShow: *D I N O D I C K S*

[@happyfacefries]

This sums it up to a T

[@spacesharkwriter6554]

Jurassic park in an alternate universe John Hammond: welcome to Jurassic par-WOAH WOAH UH, THATS NOT SUPPOSED TO HAPPEN, DOCTOR WU SAID THEY WERE ALL FEMALE, HEH HEH, LETS UMMM GIVE THE BRACHIOSAURUS SOME PRIVACY Ian Malcolm: life uhhhhhh.....found a way?!?

[@aimeem]

Probably prehensile dino dicks

[@M.J.Leighton-fs2ic]

To a T-Rex maybe lol ​@@happyfacefries

[@CharmsDad]

I always like when presentations about dinosaurs give both sides in areas where there are conflicting opinions. That’s just good science and shows that the presentation is a reputable one.

[@stax6092]

The claws of Therizinosaurus look like those of the Mega Sloth, so maybe they filled a niche similar to that.

[@juanbacisneros]

Stax True!!

[@OnlyHopeRemainsTTV]

I was thinking that, too!

[@binky2819]

I think that too, it's possible that Therizinosaurus was a giant, ground dwelling version of today's sloths.

[@TheReZisTLust]

It's for fellow butt cleaning

[@theMcWOPPER]

Hell naw

[@infiniteunknown4332]

My theory on Therinzinosarurus' Claws consist of 2 things, one of which was included in the video. 1. The claws were used for grabbing vegetation. 2. The claws were used for self defense. Even through they are believed to be herbivores, there is still good reason to have a self defense against other predatory dinosaurs.

[@Indoraptoad]

If anything, they would at least be intimidating

[@dragonfirepheonixrage9655]

I would say it depends on how strong they were if the would break while hitting a predatory dinosaurs body if not may they do use it for defense

[@drfill9210]

How about sexual display?

[@TheCalm25]

The writing and Hank's delivery are such a sexy pair of informative communication. I love this channel. I'll keep watching for another 10 years I guess.

[@rickinielsen1]

I never understood the confusion about the sails on creatures that hunt in water. They would obviously loose a lot of body heat to the water, which would require them to burn more calories. If part of the creature sticks out of the water while they lie at the surface while looking for prey, then they could partly heat their bodies from the sun. Not only would the sail receive direct sunlight, but also reflections from the water. That would be an obvious evolutionary boon, that could easily evolve a small ridge on their backs into a large sail.

[@TragoudistrosMPH]

Possibly, though, if they aren't fully warm-blooded like mammals, they might not need to maintain a high body heat like we do.

[@javierpowell4705]

@@TragoudistrosMPH but we maintain that heat naturally, cold bloods loose precious heat pretty easily, they need the sun, plus the sun wouldn't be too hot if it's only during hunting but, probably enough to keep it going

[@ZombieBarioth]

@@TragoudistrosMPH Cold blooded creatures still need to maintain though, even more-so than us even considering their bodies would slow down along with their bodily functions, which could even stop if they got too cold. If anything they would have even more need for a sail to maintain their body temperature. Worse-case scenario they could drown if they got too cold.

[@kingpotato7183]

@@TragoudistrosMPH do you even know what being cold blooded and warm blooded means

[@TragoudistrosMPH]

@@ZombieBarioth ectotherms have minimum body temperature requirements, but they are lower than that of mammals. Their metabolisms just slow down, whereas a mammal's stops. Ectotherms need about 10% the amount of food we mammals do, by body size. Reptiles famously can eat one meal a week or month, for example. The advantage we have is that we are always at a temperature that can act at maximum efficiency, while ectotherms need to warm up to get to that peak. Mammals die from hypothermia, though. We're high risk, high reward body types. Another weird example is that constrictor snakes more easily kill mammals, than reptiles, because it takes forever to smother a reptile (some an hour) because of their metabolism, while mammals (birds breathe Totally differently, so it is a different reason but similar effect) suffocate quickly. (Blood pressure is a different story).

[@Im-Not-a-Dog]

Paleontology Rule #1) If you don’t know what a feature did, it was for baggin ass. Honestly, it tends to be accurate in most living dinosaurs with seemingly useless adaptations. Think peacocks or birds of paradise. Male ostriches also display this to a lesser extent.

[@wschippr1]

NButler1993 Mammals as well. A lot of weird features on mammals are used primarily for sexual displays. Antlers being a prime example and an energy intensive display at that.

[@Im-Not-a-Dog]

Alex Noa While antlers play a role in sexual attraction, they have a practical application for defense from predators and competition between males for more than just sexual reasons as males use them in fights over resources as well. The same cannot be said about the adaptations I was mentioning. People assumed that the peacocks tail was used for a defensive display but it doesn’t actually seem that effective and most male peacocks will flee from a predator rather than attempt to threaten it with its tail when put in tests.

[@wschippr1]

NButler1993 Um, no, antlers are used for sexual displays (and the fighting between males falls into that category btw). Many species of deer actually shed their antlers after mating season because they're such a huge resource drain. The more extravagant the antler the more likely they are to shed them. Horns are sometimes used against predators, but it's still pretty clear that their primary purpose is for sexual displays.

[@wschippr1]

NButler1993 You are making the false assumption that just because an appendage can be used for x means it evolved to do x. This is wrong. A deer lashing out with its antlers when being attack doesn't mean that it evolved them to do so. The fact that many deer do not maintain their antlers year round indicates that they're not that useful for fending off predators.

[@hedgehog3180]

@@wschippr1 Yeah with stuff like that it's similar to how you might think to use a screwdriver for self defense if that's the only thing you have on you. That's not it's purpose but in a pinch it's better than nothing and like most animals will understand that if you impale something they die. But it does become very obvious when you look at how the horns are often positioned that they aren't meant to do serious damage, if they were they'd be pointing forward but usually they point up.

[@rubbers3]

So I guess "it helped to attract mates" is similar to "something massive hit it" we all know and love from astronomy?

[@misanthropiclusion]

also "it was used for ritual purposes" for archaeology

[@Rozwarty]

"It makes a black hole" from physics

[@fumomofumosarum5893]

a woman's breast - technically- doesn't need excessive fat tissue to generate milk for offspring, especially in our modern age - and yet some woman have very large breasts ^^ i wonder why...

[@eriksvitok9356]

fumomo fumosarum its for ritual purposes

[@campkira]

Not everything need to have a propose. Your tailbone and appendix for example.

[@eddypalogrande]

That awkward moment when you confess your secret kink 10:31 ..

[@muscovymapping8896]

I thought the same thing lmaoo

[@scroopynoopers2892]

When I heard that I was like wtf

[@ConstitutionalConservative1776]

Although, he does strike me as the kind of person that would appreciate a phallus-like structure

[@nightshadekelly]

My secret kink is someone with a secret kink that tries to hide!

[@Temp0raryName]

"OMG the script said 'which scientists are looking forward to finding.' Just keep going, they won't notice... No, don't be stupid, it's the internet. My secret is out!"

[@frankmazzur5674]

African elephant ears radiate heat, may help in hearing, are used in displays of aggression and for various forms of signalling. In other words, they have lots of reasons why they are so big. So, why would we think dinosaur features would have singular explanations?

[@_Atzin]

I think it's not so much a singular explanation but a main one, I believe in regard to elephants, the ears are mainly for dealing with heat.

[@frankmazzur5674]

@@_Atzin Perhaps, but in evolution explanations can be more complex and interrelated. Following the elephant ears example (just one of many we could pick) perhaps the ears evolved to be a bit larger for heat dissipation, only later to grow enormous after being re-purposed as threat displays. The Indian sub-continent and south Asia are just as hot at Africa (or very nearly so) yet Asian elephants seem to dissipate heat quite well with ears a fraction the size of their African cousins. I will admit that I'm not an elephant biologist, and maybe their larger size increases the African elephant's cooling needs, but you get my point.

[@frankmazzur5674]

@@celinak5062 Take a look at the African forest elephant (third and most endangered species)-also smaller, also lives in jungle yet still has enormous ears.

[@chriswatson7965]

There is only one reason for elephants having big ears - heat dissipation. They don't assist in hearing, and smaller ears are as effective at communication. As for threat displays 1) against predators - completely unnecessary 2) against rivals - no significant difference between male and female ear size. Indian elephants have small ears because they are descendent from mammoths. The rate of change of ear size from mammoth to Indian elephant indicates either heat dissipation is a small effect, or it requires large changes in the genetics to get a change in ear size (less likely). There are plenty of features and adaptations that have multiple uses, but the elephant's ears is not one of them.

[@frankmazzur5674]

@@chriswatson7965 so you are saying African elephants don't use their ears during threat displays or other forms of signalling? I suspect that would be news to anyone who has seen an angry African elephant anywhere, ever. (Edited to add video link of what an angry elephant looks like kzbin.info/www/bejne/pIWQaoumrpt-jrs) As for their assistance in hearing, I did say "may" because the resource I was quoting, written by an elephant researcher used the word "may". If you have conclusive proof that they do not help focus sound, you are welcome to take that up with the scientific community, but I will stand by my use of the word "may". Finally, according to the sources I found, the ancestors of Asian elephants and mammoths diverged from those of African elephants 6 million years ago, and from each other 5.5 million years ago. Asian elephants are not descended from mammoths, according to the actual DNA evidence. They are slightly more closely related to each other than to African elephants, but only very slightly. Other than that, you are 100% correct.

[@elmohead]

Cop out answers in scientific field: Archaeologist found a mysterious object - err... it's for some kind of ritual. Palaeontologist found a mysterious bone - err... sexual display. Astrophysicist found a mysterious object - err... something to do with black holes.

[@margaretschachte489]

So true

[@Ytremz]

I find this comment strange. Some kind of sexual display of ritualistic attraction, I'd say.

[@sujimtangerines]

Another one for astrophysics:. Don't know why it orbits that way, or how it got to be there, or why the axis seems off... Something must have hit it.

[@elmohead]

They would never do that.

[@deeya]

most physicists just go for " *quantum* "...

[@EduardoMartinez-fk2pv]

“Sexual display” is paleontology’s “a wizard did it”

[@TheStarfreak911]

With the Stegosaurus' plates, do scientists know if they had a strong structural connection with the back bones? If so, it could be that the plates also served the purpose of making them harder to be nommed on from taller predators like the T-rex. This would mean the underside of the dino would have been the easiest place to eat from but would be difficult to get to due to the low center of gravity.

[@GandalfTheTsaagan]

Thing is, the biggest contemporary carnivores were smaller or on par with Stegosaurus, so attacks from above wouldn't be too common

[@nkordich]

​@@GandalfTheTsaagan Tyrannosaurus existed much later, but allosaurus nicely overlaps stegosaurus, and you can often see skeletal recreations next to one another: en.wikipedia.org/wiki/Stegosaurus#/media/File:Allosaurus_attacks_Stegosaurus.jpg The earliest stegosaurids were much smaller, at about a meter and a half, and their plates were more like horns. As such, it seems more likely the spikes along their back were originally to stop predators from biting down. It's possible that the evolution from horns to plates may have indicated a shift in purpose away from this. One theory about their defensive purpose is that the plates served to increase the apparent size of the stegosaurus, making them more daunting to the allosaurus than ornithopods and other possible prey animals. An alternate defense-purpose theory comes from Bob Bakker, who believes the plates could be tilted horizontally, so rather than mostly vertical, they could be angled toward a predator. In any case, there are a lot of theories without much way to prove any of them, at least not yet.

[@brandonfoley7519]

I think they were loose

[@Wolfie54545]

T Rex is a Cretaceous animal, Stegosaurus is a Jurassic. They did not live at the same time.

[@gravel9270]

@@Wolfie54545 I remember the fun fact: t. rex is lived nearer to us humans than the last stegosaurus.

[@Weirdoid]

Can we learn of dinosaur eyes from mimicry of them? Preserved Jurassic era lacewings with eyespots on their wings to scare predators have been found.

[@Master_Therion]

My theory about stegosaurus plates... they ate off of them.

[@marilynlucero9363]

"Thagomizer" still is the most awesome name for a spiked tail.

[@Benzy670]

Master Therion your hypothesis. Theories are proven and backed by scientific evidence.

[@ggalaggo]

Dude is your life's purpose to crack puns on KZbin? I see you getting top comments everywhere lmao. Are you some pun generating demi-god?

[@MrFreakHeavy]

@@Benzy670 Theories aren't necessarily proven, they are just an explanation of reality based on evidence. Some theories have not been accepted, and there are many theories that suggest different things for the same subject.

[@craigcorson3036]

And my theory is that, by vigorously fluttering them, they were actually able to fly for short distances, with an assist from their hydrogen bladders. ;-)

[@GeFeldz]

3:41 now that's an impressive moose! Granted, moose are significantly larger in northern north america than they are here in scandinavia, they're still VERY large animals over here. 30+ "spikes" on the antler crown is unheard of afaik. 16-20-spiked crowns are pretty much once-in-a-lifetime trophies for dedicated moose hunters, if that. I was lucky enough to take down a bull moose of about 650 pounds (estimated) and he had 11 spikes in his crown.12+ is considered impressive and 16 is VERY rare.

[@KeelyIleanBaker]

Nice takedown! I bet he tasted delicious!!!

[@GeFeldz]

@@KeelyIleanBaker He certainly was!

[@michaeldeierhoi4096]

@GefFeldz. That moose you took down you said was 680 lbs. Don't you mean kgs because at 680 lbs is small even for a female? Males don't even range that low unless they are juveniles.

[@kaiceecrane3884]

Hippos are herbivores and still have sharp tusk, they use their tusk to fight to protect themselves and their territory; why would other animals not have a similar ability to defend themselves with sharp parts even though they don't use them to eat food

[@andrejansen3281]

KaîÇee Crane Good point. Especially if it was indeed a pot-bellied herbivore that didn't have other means to avoid predation

[@KhanMann66]

It’s strange how tusk are common among mammals yet rare in reptiles. Why is that?

[@Dragrath1]

Though don't forget that few Herbivores are pure Herbivores Hippos will not turn down a easy snack neither will cows deer pikas etc. but yeah many herbivores will use structures that have other purposes as defensive weapons when cornered.

[@KhanMann66]

@Joshua Frenkel Whoa that's awesome.

[@darkwoodfarms1040]

Sharp teeth are also good for woody vegetation.

[@cdanea]

SciShow has a new writer that loves 'extant'

[@LearnersNation]

😁😂

[@evilchicken17]

They'll start to hate it after repeatedly hearing Hank pronounce it.

[@xxKrazyKxx]

I've noticed it popping up in a lot of "scientific" videos on KZbin lately.

[@jmcenanly1]

Since birds are a subset of Dinosaurs, we can assume that the varied behavior of birds are a small subset of Dinosaurs behavior. They were just wild.

[@LearnersNation]

Couldn't agree more.

[@MrFreakHeavy]

lol they probably had awesome parties!

[@chickenfoot87]

As the owner of several birds, this is terrifying. Giant toothy birds would not be a good time.

[@thomashughes_teh]

I have never seen a four legged bird.

[@Shaeress]

Which would be a fair assumption for early birds right after the extinction of non-avian dinosaurs. They've had quite some time to diversify since then.

[@WoebringerofDoom]

"And here children, we have the Duckdicked dinosaur..."

[@merlemorrison482]

I wouldn't say that we "know" this about dinos, but I would say we "currently believe" this.

[@Her_Viscera]

The word "know" is basically useless.

[@butterskywalker8785]

you never actually know anything,you just believe your observations and your senses,you never certainly know if we're in a simulation or not

[@eleSDSU]

Knowledge is justified true belief.

[@nicefam4slayer278]

The first image of the stegosaurus is from the Carnegie science museum in Pittsburg Pennsylvania

[@juliebarkley1066]

Those claws remind me of a berry take. I wonder if it used them to rake bushes to pull out leaves into a big pile, then ate the pile. It would be more efficient than eating straight off the bush.

[@jolisamurphy2322]

I genuinely enjoyed this. Informative and funny. It made me smile and think, I couldn't have asked for more. Thank you.

[@NotHPotter]

Therizinosaurus kinda reminds me of a giant ground sloth. Perhaps they filled similar ecological niches?

[@berengerchristy6256]

that's what I thought: if there are any future smart creatures after humans wreck the planet hopefully they don't think sloths were terrifying predators. rather, they were canvasses for algae to grow on and the easiest morsels for jaguars to eat

[@theMcWOPPER]

Hell naw

[@thexplodenator3007]

I love it when you shed more light on the awesomeness known as dinosaurs

[@badbiker666]

Regarding the Therizinosaurus, I like the idea that they used those claws primarily for digging up roots and tubers. And why not also use them for defense, when necessary? I mean, if I had scythes on the ends of my fingers, why not put them to whatever use was needed in any given circumstance, even if I evolved then to root around in the soil?

[@LordZeebee]

yeah at the very least it'd serve as a superb deterrent lol

[@Saurophaganax1931]

I have a hard time seeing them using those claws for digging. There’s two main issues with it. The first is that the claws are long and thin, which isn’t good for digging. The first rock it hits is going to send it to pain town. Secondly, they couldnt turn their palms downwards to scoop dirt. They held their hands in a near permanent clapping position with palms facing each other. Not very good for digging.

[@brendanholbrook6370]

I think spines Make you harder to eat. Most bigger things would bite downward. And having spines may deter this when growing up. Like fish with spines?

[@MLDeS100]

#3, maybe they are similar to sloth claws

[@SephonDK]

The moment I saw Therizinosaurus I immediately thought that someone would propose it was similar to the claws of a giant ground sloth. Happy to see the scientists thought the same thing, even if it's most probably not what they were for.

[@dave900575]

The thing is, no one's ever found a pot bellied plant from the same fossil record.

[@CL-go2ji]

🤣

[@divine-x4457]

i think it’s pretty obvious that therizinosaurus uses its claw t protect itself as one thing it does

[@sarab3888]

The claws of Therizinosaurus could have just been used to strip bark from trees.

[@glonkerdonker132]

"The claws of the therizinosaurus pierces the younglin" Sorry i couldn't help it

[@jaschabull2365]

I seem to remember getting to watch a video on various mating acts in Biology earlier this year, and it covered extinct dinosaurs. The paleontologist hosting it said that the way cats and their wild relatives mate seems to be the most plausible explanation to him (I think it involves the female raising her hindquarters so the male doesn't have to put his full weight on her while mounting?) So, apparently T. rexes could very well have done it kitty style :P

[@UpcycleElectronics]

Why are paleontologists socially awkward? When they don't understand something their go-to answer is "must be sexual." ....on a dating app... Swipe Swipe Swipe 'Oh she looks weird...*click'

[@TerrariaGolem]

Upcycle Electronics lol

[@HandsomeJackoff]

Upcycle Electronics please delete this comment

[@davidbeppler3032]

This is how goth was born.

[@rick149ou]

Please delete this comment, Jack.

[@nightshadekelly]

Lol i want to be a paleontologist and you just made it even more relatable

[@peterstoric6560]

6. If dinosaurs are so cool, then why won’t they fight me?

[@johndoe-qo8cy]

Hank saying he is excited to see the D. On the internet mate, you're walking into dangerous territory. :p

[@brandyrose9997]

Thank you Hank and crew 👏💕

[@barrywerdell2614]

Maybe the stegosaurus and others used their outgrowths for conserving calcium like the Armored fish, just a guess.

[@papermaniac]

thas sound possible, like the hump of a camel.

[@jmoss22]

There's a childhood fascination rekindled. More about this please!

[@e4r281]

Why do museums have old dinosaur bones? Because they can't afford new ones!

[@malemusa7900]

that is actually true!

[@cedricrobertson2893]

Ba dum tuss

[@azanathwhateley7235]

Hahoooo, you funny too

[@azanathwhateley7235]

@Aleksandr Belenko Sick burn

[@RIXRADvidz]

Bu WHA HAHAHAHAHAHAHa!!! it's a classic, an oldey but a goodie!!

[@tsmspace]

I really like the sail hypothesis of a stabilizer for using its neck,, the way that a sailfish uses it to make its nose-bashing more powerful, a legged sail-animal might use it to rip and pull when its legs couldn't get a good footing in the water.

[@aldenconsolver3428]

I tried that sail thing, I made a nice sail about 3 feet tall and attached it to my back, it was green with orange highlights. Well I went bar hopping and it only really attracted attention from one female. She appeared to be a much larger version of a Mesozoic mammal. I just really don't feel she was seeking a healthy relationship. Therefore I am afraid that the theory of sales being a sexual attractant has been overstated.

[@ryanhau1073]

Seeing that Therizinosaurus lived in the same environment as the confirmed Predators like Tarbosaurus, it's likely the Claws were used for defense

[@jarca2246]

*Who loves dinosaurs? 'Cause I love them!!!*

[@xxxsaraHelloxxx]

Yuri Arca if it wasn’t for Adam n eve messing things up. I would have had one.

[@JBulsa]

1. Sail to attract prey in the water and the air. 2. Plates camo in rocks. 3. Modern Sloths / Tree climbing 4. Wolverines 5. Dog Mating position or water transfer.

[@greensteve9307]

Great vid! Point that occured to me: Why would stegosaurus need cooling plates when other dinosaurs don't? PS: Hank, Emu is pronounced "eem-you" not "ee-moo".

[@ZombieBarioth]

They wouldn't necessarily need them for cooling, more likely they would be help them warm up faster. If they were cold blooded big flat plates would provide more surface area to catch sunlight. That would help them to stay a step ahead of predators, not to mention more time to find food.

[@madisonstewart9054]

Yah correct Aussie pronunciation - they are not eemoos!

[@brandonfoley7519]

I see what your saying but I have to disagree I think stegosaurus plated very well could have been used to regulate body heat, lots of animals today do it I think that stegosaurus just found it's own way of regulating temp Even though others might not have that adaptation doesn't make it false, maybe they have they're own way we can't see Again, I disagree but I totally understand where your coming from

[@icedragonair]

Love how science is the only place that still has people feuding by sending letters to a paper, back and forth, just like in Victorian times.

[@chinchenping]

i have CGI animator friend who worked on a dinosaure documentary. For fun, he "borrowed" a model for a velociraptor and made it hop like a kangaroo, it was very credible... and weird.

[@magnuspeacock5857]

Any way it could be found/put online?

[@GandalfTheTsaagan]

Essentially, an eagle with teeth hopping like a sparrow

[@Kittsuera]

Just because they could does not mean they did. I could run around on all fours but that is less efficient than hovering from place to place. ;D

[@chinchenping]

i don't even think raptors could have jump like a kangaroo, they don't have the same skeleton at all and they didn't live in the same environment. He just thought "hey it's funny how they look similar" and just did it. He could also have done the oposite and made a kangaroo run like an austrich or something. You know, good animators are ... good ^^ I don't think he still have the files, but i'll ask him.

[@GandalfTheTsaagan]

The bigger ones definetly didn't But smaller dromeosaurs like Microraptor might have, maybe even the juveniles of smaller species

[@boadams3207]

“We don’t have any impressions of their equipment” I have an impression. Most dinosaurs were packin’. I’ll see myself out.

[@Bakerb1942]

We all are first for loving science!!

[@trippymlgjunkrat5749]

For the therizonasaurus I have a feeling that it used the claws to shred the tougher fibrous plants and could've had a specialized stomach for the tougher plants like bark and the tougher leaves

[@RangerRuby]

I love it when Scientist are faced with problems and try to find ways around that problem! #TeamWork

[@StopChangingUsernamesYouTube]

Therazinosaurus makes me think of a giant mole or sloth. I don't have a good guess as to how it lived, but the image of a giant bird-sloth lumbering around and pulling tree limbs closer is just adorable to me.

[@davonstark3603]

The hand of a therizinosaurus reminds me of the death claw gauntlet from Fallout.

[@captaincrypto8960]

1; Moose absolutely do use their antlers for more than fashion. They use them for self defense and territory marking. 2: stegosaurus plates could theoretically have used the vessels in its plates to change colors and used them for several different things, ie, intimidation of predators, displays for mates, camouflage, etc.

[@azanathwhateley7235]

Dude you're today's Bill Nye. I know Neil Tyson is similar but he doesn't really do it the same. He's usually serious about it, as you are not. It's a good thing

[@jamesbizs]

Russel Shackleford I’m pretty sure , unlike Bill, he actually knows what he’s talking about instead of reading a script.

[@karnewarrior]

@@jamesbizs | And unlike Tyson, he's not a pretentious twat about knowing stuff, so that's good too! Truly a god among men and mer.

[@BloodSprite-tan]

um excuse you, hank green is smart and all, but he's also just reading a script, please tell me you've seen the end card before? alexa billow is this episodes writer.

[@karnewarrior]

@@malinbolambtaco1687 Bill Nye is passing out of the public eye, though, particularly as he takes on bigger topics like verbally curb-stomping creationists. Religious people are generally okay with their kids knowing about stuff like gravity and momentum, but are less chill about letting their kids watch a preacher get pwn'd by a dork with a bach degree and a bowtie. That costs views and media facetime.

[@greenanubis]

Lol, ironically Tyson is probably best expert of these three. Well, Hank and Nye had to somehow attract audience i guess...

[@jenniferpiper4293]

1. spinosaur spine used as a fin if it hunted in the water? 2. stegs plates, perhaps helped it maintain internal temp. Thick plating might radiate her back into body, offer some insulation?

[@JeremyWS]

That was interesting. I do like dinosaurs.

[@MagnusArchvile]

I'm pretty sure another common theory for the first two is that they made it harder for predators to sink their teeth around the body of the animal or something like that

[@nothisispatrick4644]

T rexes are the champions of No Nut November For obvious reasons

[@somedude140]

Because they're dead.

[@diedewip7912]

@@somedude140 short arms......

[@joeljuarez3789]

That was a great joke Rick!

[@kayakchrispy]

You spelled Texans wrong

[@jaschabull2365]

Because they're carnivores, not granivores?

[@Chrisopia]

I just creased up at the line "they just smush their cloaca together..." I don't know why that tickled me so much!

[@christopheb9221]

You forgot the defence theory for the Stegosaurus plates. I was told that as a child. But apparently they are quite thin and would be fragile so no use in defense.

[@jennashinx6939]

They were fragile and filled with blood so they were not at all good for defense. Stegosaurus is one of the later stegosaurs, and looks nothing like it's relatives. It is huge, has thin, yet very tall and wide diamond plates, while it's relatives were all much smaller and possessed smaller, thicker, sharper plates if not just straight up spikes. It also lacked shoulder spiked that MANY stegosaurs possessed. Allosaurus and other carnivores must not have spent much time hunting Stegosaurus, possibly because it grew so big, and it wasn't pressured to defend itself as much. So the plates could grow to be more fashionable rather than functional. Honestly, display is our best guess. If not sexual, then a threat display to make it appear larger. Whatever they *possibly* could have been used for, defense is not one of them

[@campkira]

Not everything need to have a propose. Your tailbone and appendix for example.

[@dirremoire]

Maybe the plates had a chemical that made them taste really bad. Or even some kind of venom.

[@jennashinx6939]

@@dirremoire poison* Venom = Offensive Poison = Defensive Stego was obv a defensive creature

[@hedgehog3180]

@@campkira That's a misunderstanding of how evolution works. Those things are called vestigial, which means that they once had a purpose but no longer do and therefor have over time gotten smaller and disappeared, you don't actively evolve useless features because first off that would be no selection towards that and secondly it would actively be selected against because it would cost energy to grow those features which would be a disadvantage. So no the plates had to have a purpose, otherwise it wouldn't have grown them.

[@mirjam3553]

I can tell EXACTLY where the pic used to illustrate scleral rings is from! :D It was eerie, seeing (almost) the photo I took some years ago show up in a video! :D (Sent mine to friends back home with the caption: It has EYE BONES!)

[@Karabetter]

I bet the fins on stegosaurus were covered with photo-chemical receptors, so they could harvest energy from the sun directly in addition to what they ate. :)

[@afifbrian2540]

best hypothesis :D

[@ZeWhiskeyMan]

is there any animals that do this? I thought only plants could do this.

[@afifbrian2540]

@@ZeWhiskeyMan Elysia chlorotica :D , yeah but the above comment weren't serious

[@Karabetter]

Stephen Arndt indeed, Afif Brian is correct that I was not meaning to be 100% serious. But I did mean it to be thought provoking. Like why is it that a running, seeing, chewing "animal" couldn't also absorb solar energy directly? After all, humans can produce vitamin D from sun exposure, which is a life essential nutrient as well as absorb it from eaten food. So why not other nutrients and energy molecules for animals from sunshine? :)

[@kylarlovelady657]

Genius

[@horacebulregard9554]

I saw someone float the idea recently that the sail on a spinosaurus could be more like the extended vertebrae on a buffalo, where they're like that as a place to connect GIANT neck muscles. I can never unsee it.

[@goldchild100]

therizinosaurs reminds me of the picture of the giant sloth.

[@drpk6514]

#1 Spinosorous sail on its back probably had a few uses. a) perhaps as a heat absorbent by the sun, b) mating ritual, c) hunting #2 Stegosaurus plates. Why no one doesn't see the exposed back of a perhaps slow vegetarian animal? They were obstacles for carnivals that would want to attack them from the back. #3 Therizinosaurus claws: The guy was a vegetarian very similar to a giant sloth. The computer modeling also said the claws werent useful for anything else other than bringing down the branches. If it looks like dock, sounds like...

[@SirDarthDragon]

"What are this dinosaurs claws for?" "BUTTSCRAATCHEER!"

[@patrickmccurry1563]

You joke, but the ability to remove parasites with scratching is a pretty useful trait. lol

[@fxvg7091]

Damn it, Peter!

[@campkira]

It could not go below the belly.

[@Chad_Thundercock]

Buttscratcher!

[@TibbiScott]

Excellent video as always.

[@CasuallyJapan]

I don’t even know what I am lol

[@fermintenava5911]

One topic you missed are Pachycephalosauridae. Since most fossil remnants of them consist only of skull parts, we know very little of them. We don't know if and how they practiced head-bumping, and a bunch of species are now thought to only be different growth stages of Pachycephalosaurus. Beyond that, we're not even sure if they eat plants or other things, too.

[@MrTigerlore]

What do you call a dinosaur who goes to prison? A dino-sore-ass.

[@huldu]

Speculations and facts are two completely different things. That's why I admire the people working in the respective fields. They won't give up until they have *facts* and won't settle on mere guesses.

[@antiisocial]

Why has no one posted "Penisaurus Rex" yet?! Lol

[@seanfoster5519]

Therizinathouras are the first adaptations of what we now know as sloths! Dig it bro!

[@ethanjones741]

All the dislikes are just young earth creationists

[@shanerooney7288]

Or they are Australians. What kind of self respecting scientist mispronounces Emu (10:03)

[@Babsza]

" Ouchy parts " Love that !

[@Zeytrixx]

Dinosaurs are still not more scary than Donald Trump’s face

[@Benzy670]

Don’t sub to me Donald Trump’s face IS a dinosaur

[@feralbluee]

really fascinating. thanks. i am amazed that the “sails” and stegosaurus plates are still a mystery. and i never put together the sails on a sailfish with dinosaur sails. there must be some connection. great vid :) 🌷🌱

[@wentshow]

My guess about the evolution of sails: they were initially protection against flying predators. How would a rodent defend itself against a swoop attack by an owl? Think of that owl sweeping down against a phalanx of sail-spears. Or perhaps protection from back-bitten by a much larger creature or one attacking from behind? It's hard to believe spinosaurus had to worry about aerial attacks, but maybe there's a jumbo-jet sized pterosaur that hasn't been discovered yet.

[@heatherswanson1664]

Today I learned a new word: extant. Thanks SciShow!

[@Caraxian]

Same. I'd never questioned what the opposite of extinct would be lol

[@peachxy3730]

it’s pronounced wrong tho

[@WILD4X4D]

At 3:41 that little comment with the moose picture. Saying their antlers aren't useful, you've obviously never had a full grown bull moose coming towards you. Even with a high powered riffle, most people will still feel the fear of having those antlers impale you.

[@Articulate99]

Always interesting, thank you.

[@MrCDGamester]

I remember a theory I read about some ten years back that some scientists thought that the the plates on the stego were used for inefficient photosynthesis. Basically, they had similar features to the leaves of plants and it was thought that a lot of stegos lived in more open plains. Meaning lots of sunlight constantly hitting them and a desire to make use of that energy

[@samiamrg7]

Maybe Therizinosaurus’ claws were for scraping and digging into soft/rotting wood like a woodpecker or breaking into insect nests like an ant-eater to get an occasional protein-rich snack.

[@tardarsauce3355]

This is a great video, and yes, PBS Eons is amazing!

[@PlainsPup]

3:40 - The giant palmate antlers of male moose and caribou are not "ridiculous features." Their palmation (as opposed to branching) may be there to advertise fitness, but they are still valuable weapons used in combat with other males for breeding rights during the rut.

[@spindash64]

What about the moose’s Chin Dong?

[@papermaniac]

KEyword : BREEDING, yes mooses also usethem for fight between each other to gain breedinng rigts, , so that is stilla featrure meant to be used for gaining mates

[@LTMinnie]

I think the spinosaurus’ sail was to prevent being mistaken for a crocodile; a territorial animal they would have cohabited with. Crocodiles have their own body language and gestures so, when in the water, the spinosaur sail would make it clear it was not an offending crocodile.

[@Frst2nxt]

I think the claws of the third creature gave it a grip on the ground for holding its ground while pulling up the plants it eats.

[@TURBOMIKEIFY]

The Therizino is the bane of my existence on Ark Mobile. The Spino doesn't kill me near as much shockingly.

[@jacksonphillips1346]

As a small child, I was told that the diamonds on stegosaurus were for protection. I didn't understand how. I'm glad I'm not the only one that was confused.

[@ellenmcintyre1247]

Sloths have BIG claws...they use them to climb around/hang from trees. And the trees back in the fossil record were BIG.

[@dragon091327]

Studying their foot prints has brought some insight to the way dinosaurs behave. Also I am pretty sure dimetrodon didn’t have a sail but a hump and some spines.

[@zndxn]

The sails were primitive organic solar collectors. A Spinosaurus submerged under the water and swimming all day would be cold, and a big sail sticking out of the water could have kept it warm. I think that's what all the land sails were for, warming. A big animal would have had to work less to keep its body warm and active if the sun could do that for it.

[@DStecks]

The problem with phylogenetic bracketing for dinosaur mating is that while crocodiles and birds could easily reflect the ancestral archosaur condition, those groups never had to deal with the biomechanics of a multi-ton body. Birds probably give us a better idea of what theropods, especially small theropods did, but sauropods and ornithischians had almost 200 million years to evolve and didn't leave us any living descendants.