The T. rex Lip Debate is Over! 

I am not gonna lie to you, birds DO have lips, but not at the front of their mouths because their dentary and maxilla are covered in keratin. They still have lips in the corners of their mouths and as long as we don't get something that contradicts it, I'm gonna avidly keep giving non-avian dinosaurs bird-like rictuses. Bird lips are very flexible, it's always so fascinating to study them when dealing with some corpses.

Whats funny is that many of us grew up with depictions of dinosaurs with lips. In the early 80s most books and media that I encountered were full of art from the 1920s-1960s (presumably because it was out of copyright) and those typically showed dinosaurs as giant lizards... complete with lips. It wasnt until Jurassic Park and the tidal wave of dino renaissance depictions popularized the toothy look which always felt a bit weird IMO.

I don't care what the science says, I'm going to die on the hill of t Rex having extremely impressive and movable lips specifically adapted for kissing.

now imagine a world where dinosaurs get lip injections because they discovered vanity with time

I keept saying it and fighting with people. Lips are the norm in tetrapods. Exposed teeth is usually a derived feature, evolved for a specific purpose.

I'm an author. And its really frustrating when you find out new data about certain dinosaur anatomy [spinosaurus and dinosaur vocalizations e.g.] you have to rewrite whole chapters. For the past two years I was with the lipped theropod notion. Keep up the good work man! 😎👍

The uncovered teeth of crocs seem to be more towards the exception than the rule. I appreciate when you discuss ethical issues! Scientists can be as problematic as any other group of humans.

Imagine if the guys that hated feathered dinosaurs a few years back used the same argument with dino lips as "not scary like they used to in the old movies" logic. Leave those guys in Komodo island and let's see if they last a week among those giants without pissing their pants.

> It probably isn't over. Though it deffinitively has been reinforced

Who wouldn’t want lips as kissable as Tyrannosaurus?

I can't believe people look at an Iguana or a Komodo Dragon and say "Oh yeah a lack of lips would be totally less threatening."

Always love updates about old drama

So, if lips keep teeth moist, and therefor the contemporary crocs don't have them because they are aquatic, did terrestrial crocs in the past develop lips? After all multiple lines of crocs became secondarily terrestrial.

There’s something perplexing about how up in arms some people can get about whether or not some dinosaurs had lips. People have literally purposed sauropods had TRUNKS for crying out loud! This seems like a small, small thing to get up in arms about, no matter what side you’re on.

"Imagine needing lips to keep your teeth moist." -crocodilians

That’s interesting, and I always liked the look of lips.

I remember having T-rex toys in the late 80s which were still depicted as standing upright, dragging their tails on the ground like a kangaroo. It's fascinating how science and biology is all connected.

Thankyou! That verifies my research on my Spinosaurus! I agonised over this, but after reading Mark Witton's Paeleoartist's Handbook, came down on the side of lips. I think he looks much better with them. (The Spinosaurus that is!)

Could this mean that the sabre -toothed cats may have had their longest teeth covered by lips? What about the marsupial sabertooth Thylacosmilus?

"Varanus Salvadorii" The best pet horror show for you.

I wonder if the extinct land crocs, which presumably spent little time in water, had lips to keep their teeth moist.

Thank you, Ezekial. No derf theropods.

I am officially calling this Rexy Lips Day.

I think lips on dinosaurs make them look more like a living, breathing animal :] but that's just my opinion I think that hadrosaurs with cheeks, and ceratopsians with cheeks, make them look real, too

Also a bizare thing is that the jp rex didnt have lips there but the raptors did

This video brought to mind the image of a Tyrannosaur investigating an object using much more motile lips than one would expect, not unlike an ape might. Which is unlikely to be accurate, but is definitely a new sort of uncomfortable cute.

Crocodiles also replace their teeth through out their entire life. They don't have as much of anneed to preserve them like dinosaurs do.

Looks like two major paleontologists Thomas Carr and Julien Benoit are "Completely unconvinced" by this new paper's findings. *The debate is not over.*

There are mammals today that have exposed teeth without prolonged water dips. Boar tusks and that tiny fanged deer(ungulates are the biggest exception to the moisture requirement for enamel rule). In terms of prehistoric mammals, Smilodon tends to have very long sabers (6 inches) that have no evidence of being covered in skin. Homotherium though have evidence of enough skin material on their lower jaw to match their still huge but manageable 3-in fangs so they can still be using their lips, just the opposite side (this is how modern big cats keep their canines wet). Elephant ivory, it turns out, is mostly dentine with collagen fibers crisscrossing the structure lattice, so it doesn't need to get that prolonged moisture requirement.

Giving t Rex lips makes me think of komodo dragons.

The easiest way to tell if birds have lips is to see if your local Chinese restaurant serves Birds’ Lips Soup

I imagine T-Rex looking like a Pit Bull on two legs both so cute yet so terrifying

You are all wrong, I propose we put giant bulging red lips on T-rex and other dinos!

Plot twist: their tongues were large enough to cover the teeth.

If t rex doesn't have lips, then how do they kiss?

I appreciate you addressing that there was an abusive environment for the students, always appreciate that kind of stuff

Ok, prevailing science now thinks tyrannosaurus had lips - cool. Now, let's fight about whether it could snarl! That's kinda badass actually. 😊

If dinosaurs, especially theropods, constantly lose their teeth and regrow them back during their lives, then they definitely don’t have lips because they didn’t mind losing the teeth in the first place.

Honestly, I have been drawing lips on dinos since I was a kid in the late 70's and 80s. Just because it made sense to me. I was always disgruntled as a kid and teen that movies and Paleo books at the time just drew skin on top of skeletons with no muscle mass between the two. So, my adding lips to therapods was just common for me to add. I guess I was way ahead of the game thinking "Would not the dry air and windstorms damage exposed teeth?" Years later University confirmed my theory when I was majoring in Archaeology.

Dinosaurs, more kissable than expected???

5:19 this is what I was looking for. those indentations in the jaw bones above the teeth. This would be where muscles of the lips would attach so, they probably could make fart sounds with its lips and breathing. Probably a part of their vocabulary no doubt.

Ornithischian dinosaurs probably didn't have full lips. Many theropods are beaked as well. I think studying beak evolution will help understand lip and lipless conditions. For instance do you need lips to develop a beak or is being lipless help a beak to form?

I don't know why the algorithm chose to send me to your channel. Perhaps it is a just and loving algorithm. Regardless, as a nerd who has no formal training in archeology, anthropology, paleontology, and no post graduate qualifications in any meaningful hard science, I like this. I will stay.

Honestly it's all changed so much since I was a kid, that I'm expecting someone to find evidence that these things were mammals at this point and I'll be inconsolable if that happens

I didn’t know that about the lips keeping teeth moist to help with ware and tear. It makes me think about land crocs. When a crocodylomorph became fully terrestrial was it in their best interest to also adapt lips to cover their teeth? I think that could honestly say a lot about one of our most mysterious crocodylomorphs (and my personal favorite extinct baddie) kaprosuchus. I’ve always been a personal believer of the hypothesis that kaprosuchus had a foot in both worlds. It’d stalk its prey from the water and would chase them down over short distances on land. The fact that kaprosuchus had so many large teeth that would be sticking out seems like it would place it more into the water, especially since its teeth were probably its primary hunting weapon. It also makes me curious about smilodons and the other saber toothed mammals of our past, as well as our own modern saber tooths. Smilodon, unlike kaprosuchus, had the benefit of being able to use its claws as a main weapon, and wouldn’t necessarily be relying solely on its teeth. And water deer have fangs, but they aren’t hunting and putting its teeth up to those weekly stresses. It makes me wonder if these factors all mean that kaprosuchus spent a considerable amount of time in the water. It also makes me wonder if its teeth and ramming skull were more a strange result of sexual display and secondarily a result of hunting. But it also seems like it’s foramina? (nerve holes) were more terrestrail animal oriented, though I’m no biologist so this is just my looking at the skull and comparing it to the pictures you showed. It’s skull was smooth but it looks like a ridge of holes along the teeth, other than the tip of the skull full of small holes. I like to imagine kaprosuchus as an animal similar to qianosuchus, both a predator of land and water. I hope we find more kaprosuchus fossils soon, I love this animal and the mystery that shrouds it. It’s such a great animal for someone like me who loves speculative biology to, well, speculate on.

truly a Jurassic Park raptor smirking moment

I don't think it will be over until they find a mummified head of a T-rex or similar animal.

I like either version.

I appreciate your content and also that you seem like a really nice guy

You should see the Thomas Carr study about Daspleotosaurus to know more from the other side of the debate

I think the lips look better anyways. It makes them look more like an actual animal and not a toothy, spiky movie monster.

Thb, I'm surprised that it's only now this is happening, and I find it hilarious that it's almost treated like something new.

I am curious, based on these conclusions, if the smilodon (sabre toothed cats) had extra enamel on their potentially exposed big teeth?

Well if they didnt have lips then where did the the lady t rexs wear their lipstick?

I was 95% sure this was an April fool's video when I saw it come up.

I didn’t think this was a debate after 2016

Harryhausen made his eponymous Allosaurus with lips in his film, "The Valley of Gwangi". In fact, in once scene, his lip is shown starting to curl up to show the teeth underneath. Maybe Spinosaurus didn't have lips?

Great, now I can't un-see a T-Rex using it's lips to smile at it's victim. 👄

5:32 thats a pretty chunky meal for a single swallow 😅

I vaguely remember from a crocodile doc that they can have exposed teeth because they’re mostly aquatic animals. Teeth exposed to the air constantly can degrade them so I’d think dinosaurs would have lips covering them?

Julien Benoit have very interesting argument AGAINST lips. He note that beaks are incredibly common in dinosaurs relatives, it appeared several times in birds, several time in non avian theropods, in ornithischians, pterosaurs, even crocodilomorpha and of course, in turtles. Plus there is an hypithesis on disposable ramphotheca in sauropods. On the other hand there is very few instances of beacks in lepidosauromorpha and other reptiles, the only case I can think of is Eretmorhipis. It's also very rare in synapsids (platypus and dicynodonts). It's sounds like evolving a beak in archelosauria is very easy and happens everytime the diet is suitable for it. Like they all have an already a hardened keratine around the mouth with teeth just embeded in it.

Without soft tissue preservation it's still a bit of a tossup, as comparisons to unrelated taxa (like what they're doing to Dunkleosteus now) are notoriously misleading & unreliable. I'd take any paper comparing Archosaurs like Dinosaurs to Lepidosaurs with a hefty grain of salt.

so it boils down to one dino had lips so all dinos have lips? T-Rex skull has foramina on the bottom jaw but not the top and their top teeth get darker as you go down showing that they where exposed. but what ever make you happy because until we see a live one no one will know. At one point they claimed it had feathers so who know.

I always pictured them with lips because I think of them as lizards, and every sharp toothed lizard I can think of does not have exposed teeth. Crocodilians do, but they're not lizards.

While I was watching this, I was like “please say they had lips! Please say they had lips!!” But not because of a debate reason. The reason why is I like to sculpt dinosaurs (mainly theropods) and they aren’t usually too accurate (still working on my skills…) and I just wanted one thing to be accurate and well, yeah I got at least something pretty accurate on my sculptures :/

What confuses me more is, why's a tREX look like it has skin slapped on its skull, unlike other animals (for example, a bear for instance: bears have small skulls big heads yet trexs are like flesh on its skull. How do we know they looked like that? It just literally the same shape as its skull with no meat on it what so ever unlike animals who look somewhat different compared to there skull structor.)

Thank you for talking about the abusive advisor issue. It's about time there was more transparency about the abuses of power that are unfortunately ingrained in many of our systems, including academia. But it's not fair to blame co-author(s) on a paper for abuses by one of the authors -- you put out papers with whomever else is doing the work, & abandoning a multi-year project in this publish-or-perish setting would likely mean losing your career...

You should make a video on the paleontological slapfight over Dravidosaurus sometime

Okay hear me out What if they do have lips but have the ability to lift them up when they're trying to snarl or look intimidating or have facial expressions. (Not like humans or anything but something minimal like wolves snarling and stuff)

The closest relatives of dinosaurs are birds and crocodiles which are all grouped together in the order archosaurs. Birds are of course the closest relatives because they are theropod dinosaurs themselves. Neither birds nor crocodiles have lips, and the only living group of reptiles to have lips is the archosaur's sister group, the lepidosaurs (which includes lizards and snakes). Mammals doesn't count ofcourse because of their distant relation to reptiles in general and due to the fact that they posses muscular lips(the muscles also provide support to their facial skin) which even lepidosaurs do not have either. It would seem that lips are the most logical thing for an animal to have but that's not the case. If we take into account the morphology of the mouth and the structure, lips are not a necessary ''apparatus''. Also, the areas on the maxilla and dentary bone that appear to supply blood to lips could also provide blood supply to nourish large facial scales as well. Also the mandibular teeth (the lower jaw) are protected inside the mouth, a feature *unique* to theropod dinosaurs. And because the lower jaw fits inside the upper jaw, you can see how far down to the lower jaw the upper teeth reach. Not the best space for a lower lip to develop and provide cover to the upper teeth especially without the present of facial muscles to support the lower lip. As for the teeth in the upper jaw, firstly we see animals today with exposed teeth (like musk deer or water deer that have exposed fangs outside the mouth all the time) and secondly unlike mammals reptiles in general shed their teeth constantly in their lives. So, again, no need for an upper lip to cover and protect them. Large facial scales could also provide some good cover as well and be better suited for intraspecific competition. I don't believe that the lack of lips in crocodiles evolved due to their water lifestyle. If that were the case cetaceans like dolphins would do the same, but most dolphins have lips. So, It could actually be an ancestral archosaurian trait. If the ancestral trait of archosaurs is indeed lipplessness/the absence of lips, then it could be passed on to their descendants the dinosaurs. Many believe also that Trex had such salivary glands that were able to produce just enough moisture within their jaws to keep the teeth from falling over the threshold(see komodo dragons), or at least maintain them enough until eventually shed them. Maybe the climate played part in this. Climate was more humid back then, but could environmental humidity be so effective to protect dinosaur teeth? I don't know. Along with many unknowns there is the unknown of tongue which could also play vital role in the dinosaur oral physiology.

The issue I have with this, is the crocodile monitor has a concave in its upper jaw rather than a Convex like T-Rex

I can see a trex having lips do this argument never bothered me although I do like the idea of their teeth being shown like in Jurassic park. HOWEVER, I will never buy that trex was feathered unless they reverse engineer one or go back in time to get one to prove it.

since dinosaurs were the father of birds and lizards, trex must've been with a kiwi or cassowary type of feather... but with a lizard lips...

Sebecidae was a clade of reptiles that survived the K-Pg extinction event. While distantly related to crocodilians, they were ecologically closer to the dinosaurs. Barinasuchus and others from the family were terrestrial predators. So the question is, did they have lips to protect their teeth or not? probably not

Am glad this debate exist though cause it just teaches us alot about dinosaur which is a good thing, but I sure do like to think most dinosaurs had lips like these. Also I wish y'all are having a great day

This is the last place I expected to learn about the purpose of lips. You think a dentist or some biology book about the oral cavity would've mentioned it.

Why isn’t anyone bringing up how crocs and theropods regularly replaced their teeth?

I'm sure that I watched a video saying crocodiles have multiple replacement teeth during their lifetime. So being exposed to excess wear, is not so much of an issue? Would T-Rex have multiple replacement teeth during its lifetime? T-Rex looks more menacing without lips.

Accuracy vs Badass

I read that as “the T-Rex lib debate is over” implying this had to do with something liberals were saying something about dinosaurs.

I knew of this back and forth from before, but I didn't know about the evidence. My thanks for giving such a clear set of evidence.

Am I the only one who's always thought they look cooler with lips?

Will you be able to also talk about a similar debate when it comes to the Pachycephalosaurs? The whole “how far back does the mouth go” because some have portrayed the dinosaur with a smaller maw while others portray it with a sort of toad-like wide maw that goes all the way back near the eyes. Idk if this is like a skeletal mistake or not where people took the skeleton at face value and said “yes it opened its mouth that wide.”

Oh finally! I can sleep now, this debate has been bugging me for years.

I like the information, especially as someone who kinda tries to keep at least somewhat in the loop concerning things like this. I'm seriously waiting for anything solid to be released about Spino's since that seems to flip flop every few months.

I need that Diliphosaurus art you have in your office. It looks amazing.

I don’t even get the whole “diNoSAuRs WiTh LiPS arN’t sCAry” argument. Because dinosaur movies in the early twentieth century (while obviously outdated) at least had lips, and people still found them scary. Like Valley of Gwangi, Rite of spring Fantasia, and the 1933 King Kong T. rexs. People actually ran out of the theater watching 1933 King Kong. But now we’re complaining about that aspect not looking scary enough? In fact horror shouldn’t rely on a “sCAry LoOkInG MUnSTeR” anyways. Jurassic Park isn’t considered a horror movie because the dinosaurs look scary. It’s scary because of the claustrophobic feeling you get when you’re trapped with them. So this argument is ignorant on both a scientific level, and an artistic level. Edit: Actually the more I think about it now; even the Velociraptors and the Dilophosaurus from Jurassic Park, had lips that covered their teeth. So even the film that started this whole trend knew dinosaurs had lips.

Me at 3 AM

Does that mean Spinosaurus don't have lips? 🤔

Lips make most sense of just about every type of active land animal. It protects the gums from drying out, the teeth from the elements, helps with camouflage and keeps the food in your mouth while eating and keeps the dust and dirt outside. Even birds like geese keep their teeth mostly 'covered', there are very few birds who have teeth and whose teeth are visible when their mouths are closed - and basically all of those that have "uncovered" teeth have them as part of the beak structure and not "actual" teeth. Even when you take large land reptiles like snakes or lizards like Komodo Dragons - they all have lips.

It absolutely makes sense for dinosaurs to have had lips, but what wasn't mentined is the difference in life expectancy for crocodiles vs. therapod dinosaurs. An animal that lives 30 years will necessarily experience less tooth wear vs. if the same animal lived 60 years.

i mainly went with the trex with lips argument because first of all, most terrestrial animals do have flesh covering their teeth, so it would be reasonable that a t-rex would have that too. second, our depictions of dinosaurs are very inaccurate, as dinosaurs would have much more extra meat on those bones. we show dinosaurs with little more than enough room to fit some skin over organs and muscle. real life animals are always at least a little larger than their bones show, so the same rule would likely apply to dinosaurs as well.

but can we just entertain the idea of a rex with botox baddie lips for the visual hysterics of it please and thank you

Amazing talk loved this video what is the little tyrannosaur mini skeleton figure on the shelf to the left of the video I’d love one !!! ❤

2:13 aMan? Behold aMan!

When a monitor, snake, toothed lizard or even large amphibian open their mouth(s), teeth are visible. So, there are channels/sockets/pockets that do allow for encased teeth to remain moistened as the animal is not actively engaged in predatory or antagonistic behaviors. I would imagine this to be pretty much the same for the non-avian dinosaurs, as well. It makes these animals no less impressive. Just more sensical as biological entities. I think, though, that this conversation won’t run out of gas for some time.

The early reconstruction of the t.Rex was depicted with lips

It'll make sense that dinosaurus have lips: bc without lips, it'll dry out and fall off. And the reason animals (most I think) developed lips, bc they keep the teeth moist. And yes crocidilians doesn't have lips but their teeth didn't dry out bc their semi aquatic and most (I think?) Of the time they spend time in water and it'll keep the teeth moisted

It’s never over, until we see one in real life

So, did terrestrial crocodilians have lips to protect the teethes?