Monday, May 9, 2016

Yeah I Said It... Every Sabertooth Image Ever - OBSOLETE

As I anticipated, reaction to my Hellhound rex bulldog lipped Tyrannosaurus rex argument was mixed. Some liked it, some were equivocal, and some were vehemently against it. You should know by now I have more than a little flair for the dramatic and don't think for a minute I have played my full hand when it comes to extreme "lippage" in theropods... That being said I took - for me at least - a very cautious, muted and tentative tone in that post. Not being naive and knowing full well that the backlash yet to come and the strong culturally entrenched reaction against extreme "lippage" in theropods going right to the heart of our cherished and idealized view of these animals... the struggle is real.

So in this post I am going to eschew that waffling, tentative tone and go right in for the kill shot. Yup names will be named. Things will get messy. Feelings might get hurt. Reputations might get questioned. Including my own but that's ok I am willing to play the villain.


I did go through some real searching in how I wanted to approach this post. I mean the good and bad thing about blogging is you can see where and how traffic gets shuffled to your site which means that you get to read the things people say about you - and it does affect you deeply. In various form I have been called overly speculative, aggressive, a bit of a bully, not to be taken seriously, and sort of a mean and angry guy. And I get it why people say these things about me. I have always indulged in what I consider plausible speculative possibilities. I fully admit that I have a bit of chip on my shoulder that has a lot to do with not getting recognition and blogging not being recognized as a form of science communication on par with the "peer reviewed word" but I think that is changing. I have no problem calling out the "luminaries" of the field when they leave out data, make less than ideal suggestions, and use the weight of their name as a bully pulpit. At the same time I am fully confident that if you spent any amount of real time in the flesh with me you would come away with a perhaps very different or at least more nuanced impression of me than the above characterizations. I have also seen it written that I am too passionate and excited about my own ideas. "Too passionate and excited"... think about that for a second.... I've said it before and I'll say it again there is a little too much tone policing in paleo these days when passion and excitement are discouraged. If you have not noticed science is in a war and is failing to create the excitement, fun, enlightenment, fullfillment, and yes mysticism that other forms of belief are giving people for better or worse.

Never the less it is a hard thing to tell someone that a significant chunk of their life's work is obsolete and you have to be just a little bit of a bully to do so.

To quote the great "Nature Boy" Ric Flair: "To be the man you gotta beat the man!! Whoo!"

To really s - p - e - l - l it out for you I am make the allusion to "professional wrestling" to evince the level of venom, anger, and aggression in my heart - none at all really. It is all a bit of a bluff theatrical arrangement. Of course tone has a way of getting misconstrued in writing. And no, I am not on cocaine.

That being said I am really going out to pick a fight on this one and you better believe I am coming in swinging, guns blazing, and with the gusto!!

La Brea Tar Pits. Charles R. Knight public domain

There is a bit of a problem in sabertooth paleontology. An echo chamber has evolved where one man and one man only seems to dominate the narrative over this eco-morphological grouping of animals. And that man is Mauricio Anton whose books, papers, artwork, and blogging have cast a heavy influence on our view of these animals. Truth be told he deserves the recognition and there is good reason for this respect. His artwork is captivating and in a class of its own. His books are well written, engaging, and straddle the difficult line between being overly technical and approachable. However when the artistic and scientific leanings of only one man become the main voice heard or recognized that is never a good thing in any social or scientific activity. Biases can and do slip through. Unconscious memes passed on.

Charles R. Knight. Public Domain

In the case of this one aspect of sabertooth predators that I will be addressing the cultural transmission of this meme has gone on and on for some time now, Anton as the de-facto principal conveyor of sabretooth aspect and imagery merely inherited it from Knight and paleoartists/paleontologists of the past. It is not really his creation. However Anton "is the man" in sabertooth paleobiology and paleo-art. Heavy lies that throne and any reappraisal of sabretooth anatomy and imagery can not eschew mention of his influence. There really is no way to avoid going through him.

Enough beating around the bush, it's time for Mr. Sabertooth Tiger to get some self respect, stop walking around all exposed, have some decency AND COVER UP THOSE DAMN DAGGERS!!

Yup, sabertooth predators its time to grow up and cover yourself properly with nice big luscious lips sheathing your cherished daggers. You know, like is the case for EVERY EXTANT MAMMALIAN TERRESTRIAL CARNIVORAN. Is that phylogenetic bracketing enough for you? Truth be told phylogenetic bracketing should never be looked at as the ultimate truth, just a rough road-map. It is always better to take a pluralistic approach imbuing the EPB with a heavy dose of adaptationism - Stephen Jay Gould be damned. That is the approach I took with my last post on a heavily lipped T. rex and it is the method I will take here. One caveat of the adaptationism approach is that the feature you are looking at should be one that has a strong influence on survivorship and hence sexual success. So yeah, I think a feature intimately influencing, protecting, lubricating, and assisting in killing via those precious daggers counts in that regard in a very robust way.

"But what about elephants, walrus, and other tusked mammals? Their teeth are exposed all the time."

Pacific Walrus. Cape Pierce Public Domain

You know, I have to admit to throwing up a little in the back of my mouth whenever I hear this argument trumpeted out again and again. First of all it is moving further and further away from the extant phylogenetic bracket. We already have tons of living extant carnivorans to infer from, all of them cover their teeth completely or mostly. Even the clouded leopard the cat >most< often compared or likened to sabertoothed predators covers its teeth with a nice set of lips. Secondly, tusks don't even compare in form or function to saber toothed canines. Tusks are robust, coarse choppers for plowing into trees, roots, gouging into sediments, and >most importantly< fighting with and intimidating rivals. That they are always exposed has a lot to do sexo-social signalling. Sabertooth canines do none of these activities, are often serrated, and are intrinsic to survivorship. Tusks are always out and on display because a better strategy for always getting into costly and risky fights is to bluff your way to the top by always having your weaponry out, exposed, and in full view. Sabertooth daggers were not sexo-social displays and/or fighting tools, an argument Anton (among others) has summarily dismissed. Finally tusks keep growing in many animals that have them. Sabertooth predators had no such luxury.* Comparing sabertooth daggers to tusks is like comparing a surgeons scalpel to a machete - a machete that keeps growing back. As you can tell I don't take this argument very seriously. In fact I would call it special pleading.

*Update thylacosmilids had more of a tusk like growth pattern with only a shallow enamel layer

clouded leopard. credit Vearl Brown CC2.0

clouded leopard skull

We already have numerous and unequivocal osteological evidence of direct evolutionary pressure on sabertooth predators to sheath and protect their cutlery.

Rubidgea. credit Ghedoghedo CC3.0

Thylacosmilus atrox. credit Claire Houck AMNH. CC2.0

Machaeroides eothen. credit Ghedoghedo. CC

Pogonodon platycopis. Edward Drinker Cope public domain

Eusmilus. wiki commons

Hometherium crenatidens fabrini. Public Domain

Above you see examples of the bony correlate in all six of the respective sabertooth predator radiations; gorgonospid synapsids; thylacosmilidaen metatherians; machaeroidinean creodonts; nimravidaen carnivorans; barbourofelidaen carnivorans; and felidaen carnivorans.

It is in the form of the mandibular flange. In some examples it is quite profound, in others it is a little incipient. However it occurs in all radiations of sabertooth predators giving us a strong example of convergent evolution. But to expect evolutionary pressures to exert an influence on just the mandibular, inferior section of the tooth and not expect protection from above - where blows are most likely to come from? Evolution are you drunk? Should we really expect evolutionary pressures to exert an influence on protecting just the bottom aspect of the dagger and not the top? Really, you think so? When you blink does your eyelid only cover half of your eyeball? Does a turtle carapace only protect half of the turtle? Does your cranium only cover half of your brain? Sounds like a very half-assed protective strategy to me.

Instead I would argue a much more robust inference is that ALL sabertooth predators protected their cutlery from above and below. Some species show evidence of the inferior protection via the mandibular flange which itself was sheathed in a very rugged and durable layer of "skin" a lot like the darker area of the jowls you see in your own pet dog. The upper protection would come from a fleshy expansion of the upper lip region - just as you see in any felid or carnivoran today - except larger. As sabertooth predators evolved larger and longer daggers so to did the soft anatomy that protected and assisted them evolve in tandem. Pull up the upper lips to expose teeth and bite. Let lips go loose when teeth are not in use. That a Smilodon with big droopy facial lips seems shocking now is only an artifact of the cultural shock of multiple decades of toothed exposed iconography.

Such protection would not be 100% but I would hedge my inference in favor of protection rather than not. If a feature can evolve that can assist in the struggle for survival, then it should be there.

"How dare you compare sabertooth lips to the lips of artificially selected dogs and cats? Stop it."

Nope, not stopping. The reason I posit this distinctive bulldog looking Smilodon is that artificially bred mammalian carnivorans aptly demonstrate that there is a lot of plasticity in the facial region of these animals. That humans bred them this way for looks, for better scenting abilities, for whatever... I don't really care. All that these domestic breeds show me is that giving the evolutionary context and pressures (i.e. fleshy lips to protect large dentition) there is the genetic potential in mammals that such a look >could< evolve in a wild extinct sabertoothed animal. That the bulldog look comes about is, well, try drawing a sabertooth yourself and the only prerequisite is that the teeth are mostly or completely covered by lips and it is hard to avoid the bulldog look.

Extensive Lips & Fleshy Oral Tissues Allows Enhanced Proprioception of Sabertooth Head & Daggers in Relation to Prey. We Have Direct Osteological Evidence Of This Too.

As tool using, reduced canine having primates I think we often fail to appreciate the risks incumbent upon biting down into something that does not want to get bitten into. I mean, it is a pretty simple thought but revelatory at the same time. You are literally ramming your most vulnerable external body part into another organism latching onto and often holding onto them. Let me restate that again: your most vulnerable body part is in direct line of fire for whatever you are attempting to latch onto. Remember you have to do this again and again to make a living so to speak ecologically. All of these pitfalls would be especially true for sabertooth predators which seem to show a penchant for not only large, strong and retaliatory prey but direct and relatively prolonged contact (i.e. not a bite and flee predator but a tackle, subdue, and bite predator) in which their vulnerable daggers are put into jeopardy. If there is ANY advantage you can potentially and reasonably evolve that helps you to make a killing safer, quicker, and more efficiently then that evolution will likely occur and the inference is a robust one.

Large fleshy lips and oral tissue not only provide a better means of protection from struggling prey (although not 100%) but they also provide a larger and more extensive tactile surface area to position the teeth for efficient and safe biting.

Let me just quote Anton directly here from his book Sabretooth (pp 178-79 Sabretooths as Living Predators):

"One consistent feature of most sabertoothed carnivores is the relatively large size of the infraorbital foramen... (discussion of potential muscular insertion, rodents, Barbourfelis)... there are other structures that pass through infraorbital in all mammals - specifically, the infraorbital nerve, veins, and arteries. The infraorbital nerve is a branch of the maxillary nerve, and it provides sensory nerve endings to the whiskers. Once the nerve crosses the canal, it begins to branch; and when it reaches the roots of the whiskers, it forms a true "nerve pad," creating a characteristic swelling on the sides of the muzzles of many mammals. Thus, one tempting explanation for the large diameter of the opening in sabertooths would be the presence of very well developed, especially sensitive whiskers with rich innervation."

While Anton later tempers his stance mentioning issues of direct proportionality he does mention that " the relationship between the development of the foramina and the function of the infraorbital nerve is widely accepted among zoologists."

I would go further and posit that the reason the infraorbital foramen is relatively larger in sabertooths than other predators is that not only was the "nerve pad" more sensitive - it was also absolutely larger than the nerve pad in extant felids. Why such a large and sensitive nerve pad would be needed in these predators is fairly obvious in terms of making precise and safe incisions into struggling and retaliatory prey that could easily snap off or damage your cutlery.

Anton pp 179:

"... the killing bite of sabertooths must have been quite precise in order to avoid accidents involving lateral torsion or hitting a bone in the prey, which could cause the sabretooth to break a canine. Since the target area of the bite would be outside the predator's visual field, the tactile information provided by the whiskers would be especially useful for the precise control of the biting motions. Modern cats are able to move their whiskers thanks to well developed piloerector muscles, and during the killing bite the whiskers are usually directed forward, enveloping the bitten area in a sensitive net of hairs (Leyhausen, 1979). Given the additional risks imposed by fragile sabers, improved perception would be a useful trait for the sabretooths."

I like and agree with everything Anton says here. I just differ from him in inferring an absolutely larger "nervepad" that would ultimately be more adaptive than the smaller nerve pad he prefers that only partially cover the daggers as depicted in his and all others' paleoart. I can already picture some people saying "well what if the whiskers were just longer?" nah, always better to have the tactile ability and protection. That is the more adaptive and reasonable inference not whiskers creeping down like daddy-long legs.

credit Nick Farnhill. CC2.0

As you can see in the above pic of a cheetah throat clamping Thompson's gazelle - in which the canines clamp shut the windpipe and kill by suffocation - the sensitive nerve pad is deeply enmeshed in this activity. Indeed as the bite occurs in a blind spot for the cat it is the nerve pad, especially via the whiskers, that most accurately dictates to the predator where and how the clamp should be applied. Let's think about this for a second. Many modern large felids clamp the windpipe shut with their relatively stout and blunt canines. That is a pretty refined and delicate approach and the utility of having the sensitive muzzle and whiskers enmeshed in close proximity to the bite area is self evident. However when we contrast this method with how sabertoothed predators - especially the "dirk toothed" cats likely killed - they were looking to inflict massive trauma to the general fleshy region of the neck (but also possibly abdomen). Whether the killing stroke severed arteries or the windpipe or both not really important as the end result is the same - death. So if you think about it the killing method of such sabertooth predators is  less precise than many modern felids -  as long as they get their bite in the general non-bony area of the neck (or abdomen) they good. SO WHY WOULD THE INFRAORBITAL FORAMEN BE RELATIVELY LARGER IN SABERTOOTHS? The logical conclusion is that the "nerve pad" was not relatively more sensitive per surface area than modern felids, it was in fact absolutely larger than modern felids and likely equally innervated and fed with adequate blood supply. This soft tissue adaptation would cover up those precious daggers and provide the tactile support to place the daggers in the right spot to make a killing stroke without risking torsional twisting of prey or bone chipping.

Additionally when we consider how this biting action would look and function in a sabertooth with the traditionally depicted modest sized nerve pad a real dilemma occurs. Due to the large size of the daggers - especially extreme in genera like Smilodon - the sensitive nerve pad would be scrunched up and pushed away from the bite area and not very useful for "feeling out" the best place to position a bite when the mouth was open. Indeed it would be the large teeth "feeling things out" - exactly the problem sabertoothed predators want to avoid!!

Ki Andersson, David Norman, Lars Werdelin -

You can easily see what I am talking about using this kinematic illustration above. The sensitive nerve pad would be nowhere near the bite area in traditionally depicted sabertoothed predators. But if we infer a large upper lip and nerve pad that completely or nearly completely sheathed the upper teeth even when the mouth is opened then you have a much more efficient and safer ability to "feel out" where and when to engage the teeth with prey. In this manner the teeth are protected and sheathed until the final split second before impact and the upper lip is pulled back to reveal the daggers. The tough and elastic lip need not even be pulled back that far because as the daggers are plunged into prey the body of the prey itself would simply push back against the lip sliding them back further. Large upper lips provide the most safe, efficient, and osteologically corroborated method of biting possible.

"If only we had evidence for sabertooth appearance via cave-art or other ancient depictions" ... well maybe we do.

Yup it is time we revisit the potential Rosseta Stone of sabertooth life appearance: the paleolithic statuette from Isturitz.

Now I want to make it clear - this is an artistic representation by Mauricio Anton based upon the rendering of Czech paleontologist Vratislav Mazak who himself saw representations of the original statuette in 1970. Long story short nobody actually has the statuette as it has been lost since at least the early part of the 20th century. As the statuette has been lost and been redrawn at least two times, maybe even three times as Mazak himself is said to have only seen "representations" of it, the logical conclusion is that there is a lot of ambiguity in this piece. Furthermore as the original piece can not be directly observed i.e. it can not be "tested" by others it should be in fact stricken from scientific discourse. I mean, am I wrong? Is that not the argument put forth why "private fossil specimens" can not be part of the recognized science as they can not be first hand analyzed, observed, and tested by all parties... am I missing something here? Never the less the Isturitz statuette representation has made it through peer review and is part of the "recognized" scientific literature despite the inability to test it (peer review fail #1).

In his paper reconstructing the musculature and facial anatomy of Homotherium latidens (Anton, et al. 2009) steer away from Mazak's interpretation of the Isturitz statuette representing a late surviving Pleistocene Homotherium and instead side with the original interpretation of cave lion. In Facing Homotherium Brian Switek summarizes their argument succinctly:

It should be noted that this analysis dovetails into the facial reconstruction that Anton et al perform on Homotherium in the same paper.

 Compared to:

And a cave lion representation:

Replica Chauvet Cave Lions, France

While Anton et al. do provide some compelling arguments concerning body proportion and the lack of a sloped back in the model as Homotherium would have in life (sort of like a spotted hyena) these gross anatomical inferences can be explained by the lack of forefeet in the statuette which may influence how the posture is meant to be; the possibility the figure represents a dead or lying felid; and simple errors on the part of the artist.

On the chin argument I find it less than compelling that the strong chin and large lower jaw represents the tuft of hair on a lion. It just looks too prominent and large in my eyes and is more consistent with the mandibular flange of Homotherium. There is no abrupt transition from the chin to the neck line as should be expected if the chin was simply a tuft of hair. Furthermore the manner in which Anton et al reconstruct the jaw in Homotherium is inconsistent with how we or most animals actually hold the jaw in neutral pose. They pose it in "extreme" jaw closure as if the animal would be walking around clenching its teeth shut - similar to the argument put forth on extreme jaw closure in tyrannosaurids and other theropods debunked in my last post. I suspect most animals (including you as you read this unless you are like really mad right now ;')  have their jaws just slightly agape in the neutral pose. This would dissuade the need for the teeth to fit into pockets of flesh in the lower jaw as suggested by Mazak and argued against by Anton et al. (sort of like male baboons) but instead the whole upper canine would simply be sheathed by the upper lip/nerve pad. When the jaw was fully closed it would simply lie against the thick tough, elastic, and lubricated skin of the lower jaw. Just like a clouded leopard which, by the way looks to have canines at least as big or bigger as Homotherium relative to its head size.

There is a bit of a tendency in paleo for people to see beautifully rendered muscular and skeletal reconstructions  of extinct animals and take them a little too literally. When in reality there is a lot of guesswork and biases at play in even the most "rigorously" reconstructed extinct animal no matter how aesthetically appealing. In the paper Anton et al. provide a list of references for how they reconstruct the soft tissue for Homotherium latidens:

"For soft tissue reconstruction we followed the methodology outlined in our previous works (Anton, 2003; Anton & Galobart, 1999; Anton & Sanchez, 2004; Anton et al., 1998; Turner & Anton, 1998)." 

Notice any pattern there? If a guy with the last name of Anton is the lead author of the paper and the source methodology for reconstructing soft tissue is also culled from a guy with the same last name it is not unreasonable to suspect a certain unanalyzed bias to seep through? Could there be a bit of an echo chamber here?

Anton et al., also cite the extant phylogenetic bracket as defined by Witmer as a means to infer soft tissue. But what this method lacks is putting soft tissue through the lens of adaptationism.

Anton et al. also assert that if the canines are long enough they should be seen passing past the upper lip. As evidence for this assertion they cite one example of a canine peeking past the upper lip in a dead lioness they dissected.

Now, you need not be a statistician to realize that when N=1 that is not a very large pool of a sample size to draw meaningful data from. Additionally, you need not be a mortician to realize that when stuff dies things change. Muscles grow tighter drawing back soft tissues. Mouths clench shut potentially. Anton et al. did not account for this or even mention these obvious pitfalls on drawing anatomical conclusions from a cadaver of one sample size (peer review fail #2 ). Better to look at live animals. And when you look at live carnivorans - especially felids - the upper canines are completely or mostly sheathed by the upper lip and the mouth is not clenched shut but slightly agape. Go ahead and peruse google images of large felids and see where the bias lies in terms of canines exposed or not. I double dog dare you.

Other facial features that the Chauvet lions display that are not concordant with the Isturitz statue are that the ears of the cave lion are rounded while the statuette's ears are very distinctively pointed. The spotted pelage and what appears to be a countershaded line along the torso in the statuette also do not match well with the striped pelage that has been suggested for cave lions from ancient cave art. This is a notable omission and Anton et al. deserve to be called out for not mentioning these anatomical incongruity. ( Peer review fail #3 & #4)

One of the more interesting ideas put forth is that the figurine represents a cub due to the big eyes. However I am not sure if those eyes are just stylized and if such a bold chin would be consistent with a cub lion. This idea might explain the spotted pelage as cub lions have spots and then lose them; on the other hand the cubs of striped tigers are not born spotted they are always striped.

And finally the tail. Homotherium has a bobtail while cave lions do not. Is the tail broken off in the statuette? I don't know, we can't go back and analyze which is why it probably should not have got into the scientific literature in the first place!!

Finally it is interesting that - if cave lions had manes like modern lions - a female lion would be chosen for the statuette, and not a male. I mean if you look at iconographic imagery of lions made by humans the male lion predominates in representation. It is larger, has a striking mane, is more powerful and the symbology to "warlike" civilizations is obvious; but perhaps the female lion was actually the preferred symbolic analogy used by paleolithic cultures and they in fact had a different set of cultural values than modern humans...

As you can see we are clearly in the subjective zone on this one. Switek says it takes a lot of special pleading to infer that the statuette represents Homotherium but I say it takes just as much, if not more, special pleading to infer it as a cave lion.

Look the statuette can be argued about until the cows come home - which I will abstain from doing so in the comments section so don't even try and tempt me... But it is a compelling and interesting story.

On a bigger level  this whole discourse is a great lesson in how bias can go unseen and get propagated seemingly without question.

If you go back and read the selection I culled from the Switek article he states his bias right up front:
"... and there is no reason to believe that the canines would have been covered by lips in life."

Let me just refresh you on the talking points on why large lips covering teeth should not only be the belief but the null hypothesis that should be disproven in extinct mammalian carnivorans; all modern terrestrial mammalian carnivornans sheath most or all of their teeth in lips and flesh (EPB); an extensive and proportionate "nerve pad" inferred from large infraorbital foramen located proximate to canine entry assists in vulnerable and precise tooth entry; protection of teeth, especially canines, from breakage and grit; osteological evidence of mandibular flange in sabertoothed predators infers complimentary protection from above.

It may appear that I am picking on Brian here but really he is just a fill-in for many of our biases favoring tooth exposed extinct predators, including until recently myself. Darren Naish seemed to have been favorable to the Isturitz statuette representing a late surviving Homotherium when he discussed it way back in 2006. However after Anton argued otherwise Darren seems to have changed his mind in 2010. However if you look through the comments section in that post you will see that longtime Tet Zoo commentator Jerzy makes many of the same arguments (except I don't think the canine teeth need fit into pockets like in male baboons as suggested by Mazak as well) I am making and calls out several omissions from the Anton paper:

Evidence of Morphological Features Evolving in Tandem With Increasing Canine Length In Sabretooth Predators

As cultural creations as much or even more so than scientific ones it is always useful to brace yourself for the shock and cognitive dissonance of a cherished and loved extinct animal taking on a radical, bizarre new look. We see this startling and immediate transformation but I don't think that we always appreciate that an organism is the product of evolutionary pressures and compromises occurring to it and molding it over millions of years. From our perspective large lips smothering a Smilodon's face appear to evolve over night but in reality the large lips and large teeth would be evolving in tandem as each feature influenced and reinforced the other in a feedback loop. It is only the shock and awe of seeing this change so sudden and profound that we rebel against it.

My contention that increasing lips evolved in tandem with increasing canine size is bolstered by a study showing the exact same correlation of increasing forequarter and forearm strength in sabertoothed predators occurring in concert with increasing canine length. Powerful Arms Saved Sabretoothed Killers' Fearsome Fangs, Study Shows

Julie Meachen-Samuels:

"I found that they had very thick humerus cortical bone, much thicker than any non sabertoothed cat living or extinct... I hypothesized that this extreme cortical thickness was correlated with the extremely long sabers. The robust limbs allowed Smilodon to restrain its prey so that it would be able to make a killing bite without damage to its saber teeth... These traits evolved as not only a suite of characters but as a viable distinctive prey killing strategy several times independently. This combination probably evolved several times because the predators that could best protect and preserve their teeth during prey killing survived longer and could have more offspring, thereby making this combination of long teeth and strong forelimbs a winning combination."

So should I connect the dots? Canines start growing a bit longer, lips evolve in tandem to sheath, protect, lubricate, and provide optimal tactile sensory usage. Forelimbs and forequarters get more robust to further the safety and efficiency of the kill. Canines grow a little longer still as do the lips and forequarters. The animals that can best protect their teeth and live longer reproduce the most even if it is just by incremental percentages. Repeat, repeat, repeat until you get something that looks like this:

Duane Nash. EatYourKittenSmilodon

The thing is you can still haz ur scary Smilodon even with the lips covering the fangs. It is often times what you don't see that scares you the most. If anything the big, jangly jowels add a surreal and disturbing touch. And it is all too easy to imagine that upper lip being pulled back to reveal that staggering dental load just glistening with lubricating juices and ill intent.

So just one more time to hammer down the talking points:

Facial tissue completely or mostly sheathing the upper canines as is corroborated by ALL extant terrestrial mammalian carnivorans and is the best null hypothesis; exposed and constantly growing tusked mammals use their non-serrated tusks for coarse hacking, chopping, digging, combat and display and are an inferior analog to sabertooth canines and need not be considered as they fail in comparison along nearly every metric; the clouded leopard which has long canines comparable to many sabertoothed predators covers its canines completely; all five radiations of sabertooth predators display osteological evidence of protective sheathing on the lingual inferior aspect of the canine via a mandibular flange - a logical evolutionary inference is that protection for the superior labial aspect of the canine was also selected for in the presence of a large fleshy upper lip; the presence of this large fleshy upper lip is corroborated osteologically by the relatively large infraorbital foramen found in all sabertooth predators; this large infraorbital foramen supplies the blood and nerve supply to an extremely large and sensitive "nerve pad"; the extremely innervated nerve pad provides tactile support to make precise and crucial placement of canine entry for bite; such tactile support would be diminished in sabertooths depicted with modest sized upper lip region as this area would be scrunched away from the bite area when the mouth is opened and it would be the vulnerable canines that would "feel out" where to bite; large lips and supporting nerve pad evolved in lock step with increasingly large canines and forequarter strength for maximum safety and efficiency in these highly precise yet vulnerable predators.

And I did not even mention the benefits of; having your serrations free of grit & abrasives; accruing scent particles on a larger "environmental swab"; lubrication for cleaner cutting; and preventing excess moisture loss.

Or you can keep your feebly lipped, tooth exposed, non-tactile, maladaptive, vulnerable, culturally enshrined, and just plain weird looking sabertooth predator. But I say you are holding onto a dream... Yup puny lipped advocates it is you and not I that need be on the defensive on this one. Your creature is the myth - not mine. Script. Flipped.

*Update thylacosmilids had more of a tusk like growth pattern with only a shallow enamel layer

"It is the responsibility of the scientific paleo-illustrator to make sure that his images rigorously transmit the knowledge that the paleontologists have gathered from specific extinct species."

-Mauricio Anton

*Clarification. I can already see some people misconstruing what I am suggesting with the notion that the upper canines fit into "pockets" formed by the lower lip and the mandible as suggested by Mazik. I don't think this was the case as at all. The upper canines simply rested against a more extensive lower lip region that was very durable and tough tissue - again not unlike the tough, elastic usually dark lips of domestic breeds of dogs that have had this feature artificially enhanced. Also don't confuse what I am suggesting with the debunked notion of G.J. Miller who suggested a quasi- "bulldog" look but for other reasons than what I am suggesting. Miller thought that the lip was retracted backwards to allow proper carnassial use due to the canine length. However this premise is faulty because such a lip would cut right into the masseter muscle and it is not needed anyways as modern felids are able to use their carnassial teeth without opening their mouth all the way.


Andersson K, Norman D, Werdelin L (2011) Sabretoothed Carnivores and the Killing of Large Prey. PLoS ONE 6(10): e24971. doi:10.1371/journal.pone.0024971

Anton, M. 2013. Sabretooth. Indiana University Press

Anton, M., Salesa, M.J., Turner, A., Galobart, A., Pastor, J.F. 2009. Soft tissue reconstruction of Homotherium latidens (Mammalia, Carnivora, Felidae). Implications for the possibility in paleo-art. GEOBIOS 42 (2009) 541-551

Cohen, Jenny 2012. Powerful Arms Saved Saber - Toothed Killer's Fearsome Fangs, Study Shows. January 4, 2012.

Meachen-Samuels, J.A. 2012. Morphological convergence of the prey killing arsenal of sabertooth predators. Paleobiology 38(1): 1-14

Naish, Darren. 2006. The late survival of Homotherium confirmed, and the Piltdown cats. Tetrapod Zoology. Thursday, March 9 2006

Naish. 2010. Tetrapod Zoology Book One is Here At Last. Tetrapod Zoology. October 7, 2010

Switek, Brian. 2010 Facing Homotherium. WIRED. November 18, 2010


"A Long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom". Thomas Paine

Support me on Patreon.
Like antediluvian salad on facebook. Visit my other blog southlandbeaver.blogspot
Watch me on Deviantart @NashD1Subscribe to my youtube channel Duane Nash.


Bk Jeong said...

Considering Smilodon is a modern (if exticnt) animal, and one that needs to be brought back anyways, WE WILL FIND OUT.

Also, you're not the first person to propose this.

D-man said...

Dang it, my hypothesis for teeth sliding into tooth pockets seems obsolete now (well, except for Homotherium or any of the "dirk toothed" cats). I would have at least thought that Homotherium and any of the "saber tooth cats" with short fangs would have looked like that of a Clouded Leopard while Smilodon would be depicted like how you did, since I actually also considered this hypothesis, but I had trouble on how it would work. I bet a lot fanboys are not happy.

Also, I know this is off topic, but I figure I would bring this to your attention. Apparently Dimetrodon had bone saw teeth.
Possibilty of bone saw pelcyosaurs?

D-man said...

@Bk Jeong, are you the person that goes by Acepredator on Deviantart, because I think you are. Also, I do not think we have Smilodon mummies so cloning back a true saber tooth would probably not be possible seeing how most of them lived in warmer areas. Also, when are you finishing you killer pterosaur series, it has been a year.

Anonymous said...

I just saw some things wrong with the image of the Smilodon. The saber teeth seems splayed when they should kust straight down, and the incisors are visible. Unless it's snarling, the incisor teeth should not be visible.

D-man said...

After reading this post, it seems that tooth bearing Smilodon has been sunken into the list of the most overused paleo memes in history like...

1. Shrinkwrapped Archelon (It needs to look more like a Leatherback Sea Turtle!!!)
3. Oversized Great White Shark that people call Megalodon
4. A Giraffatitan under the name Brachiosaurus

What other paleo memes that the public agrees on are their?

Duane Nash said...

@ BK Jeong Never said I was the first but I have brought some new arguments to the table that have not been put forth afaik. And no one has put it forth as confidently and forthright as I have that's for sure.

@D-man bone saw pelycosaurs? Umm not like I described for Allosaurus. A prerequisite is a long and powerful neck. Could Dimetrodon have munched through bone, definitely Robert Bakker has found loads of proof of this in Texas.

@ Anonymous Oh shit you are right!! Damn I guess I have to scrap the whole post oh well...

@ D-man "tooth bearing Smilodon has been sunken into the list of the most overused paleo memes in history" Yeah I think this will eventually be the case but it is not just yet in the eyes of majority who still favor weak lipped cats.... paleontology is a bit like politics in this way. A conservative majority, gate keepers, and small voices of dissent that typically get put down until the walls come crashing down. And then 20 yeas later "gee people were so stupid to think sauropods lived in swamps, dinosaurs were cold blooded, theropods did not have feathers, and smilodon left its teeth exposed."

Anonymous said...

Woah, never said to scrap the whole post, just said the next time you draw one, keep tose things in mind. Unless you were being sarcastic.

D-man said...

I bet your next post is about lips again.

D-man said...

Oh, I figure I would bring this to your attention. Maybe helpful if you do future posts about these topics.

It seems Allosaurus would have not actually have used the axe method and had a powerful bite as well and could take down very large prey.

mr_homm said...

Interesting arguments, and quite easy to follow for a non-paleo person like me (I'm just a mathematician with diverse interests). However, I think there is a strong argument in favor of sabertooth lips which you have not mentioned. During the summers, I teach a course preparing students for the Dental Admission Test, and one of the things we review is the function of saliva in tooth maintenance. Now of course, we're talking HUMAN teeth here, but this seems to be a fairly basic biological process which I would (naively?) expect to carry over at least to other mammalian teeth. The fact is that an adult tooth is a dynamic system which is constantly cycling calcium into and out of its enamel, and the primary vehicle for this calcium is saliva. In fact, so called "tartar-control" toothpastes prevent the calcification of tartar into calculus (yes, that's the official term for hardened tartar, not a mathematical Freudian slip on my part) by blocking the uptake of calcium by the saliva, leading to long-term decalcification. This is Not A Good Thing (TM).

The relevance to sabertooths of various types is pretty obvious, I think. Besides protecting the large canines from external damage, a (nearly) constant surface-to-surface contact would strongly promote the circulation of saliva and calcium to these teeth. What could be worse for survival than decalcified canines? Of course, I would not apply this argument to animals which replace their teeth throughout life, or whose teeth grow continuously, but I do not think that sabertooths fall into either of these categories. (Or do they? As I said, I'm not a paleo person by profession, so I could be missing some major pieces of the puzzle.)

Just my 2 cents worth.

Julius Csotonyi said...

Do we have not a single example of a saber-toothed felid or nimravid displaying sufficient soft tissue preservation to inform us on the configuration of oral soft tissues? Given the increasing number of beautifully preserved specimens of large mammals from permafrost or as mummies, it seems that it's just a matter of time before we happen upon a diagnostic fossil.

Dr. Erik Day said...

I like your idea, and sketches, but i might think the upper lips could look more like the lips of a walrus. I am not attempting to say a walrus is an example, but in your sketches the upper lips just seem to droop around the "saber teeth," like basset hound jowels. If the upper lips are to be useful and functional as "feelers" for the bite, I might think them to be thick and muscular. ie. walrus lips. I am not a biologist or paleontologist at all. But that is my thought on your sketch. A big round bull dog head, with massive walrus lips to cover the toothage. Cheers, great read.

Duane Nash said...

@mr_homm thank you so much for your insightful comment. I fully appreciate and endorse non paleo people to add their two cents. Paleontology pulls on a wide variety of knowledge and disciplines as it is. Your input is highly valued and dovetails nicely with some other lines of inference some people have turned me onto... stay tuned!! Plus you just reminded me to schedule a dental appointment.

@Julius Csotonyi. I would hope so. If not though I would side with more lips please, if that is not obvious. And as I alluded to with the comment above there is another line of evidence pointing in the direction of coverage that dovetails nicely with what mr_homm is pointing to.

@Dr. Erik Day thick and muscular walrus lips nice!! I just saw that movie "Tusk" btw too!! The reason I would hesitate on lips that muscular and thick is that walrus actually use their thick muscular lips to rip molluscs out of their shells. Sabertoothed predators would not have the same evolutionary pressure to have >so< muscular lips but who knows they could be a lot thicker than what I depicted?

Ville Sinkkonen said...

"Facial tissue completely or mostly sheathing the upper canines as is corroborated by ALL extant mammalian carnivorans and is the best null hypothesis;"

Walrus is a carnivoran. ;)

Duane Nash said...

edit *terrestrial* carnivorans ;')

Alessio said...

Another wonderful post and yeah, while my primary interest is good ol' dinosaurs, it's always nice to see you focus on the "other ones"... I really loved your posts about plesiosaurs, by the way.

Back to Smilodon and pals, well, i definitely agree with you, what else could be said?

Ville Sinkkonen said...

So I have read this couple of times now and even though I disagree little with your views regarding the lower lip and Isturitz Homotherine figurine, I do find your argumentation for floppy big upperlip lacking.

If I now recall correctly your argument for bulldogy upperlips for sabertoothed carnivorans is esseantially

1) Sabertooths didn't use their canines for other purposes such as digging, battle, or display but only for killing prey. That being the case Such specialized and crucial weaponry needs all the protection it can have thus large protective lip makes sense.

2) Relatively large infraorbital foramen indicates heavier innervation of lip and thus larger nerve pad.

3) All modern carnivorans (except walrus) have lip covered canines ergo by the power of phylogenetic bracketing sabertooth canines should be covered by lips.

*1) I don't think there is any basis to say yes or no whether sabertooths used their canines as signaling device. Looking at mammals in general with canines playing such vital role in signaling in mammals it would be reasonoble to assume that sabertooths did so as well....but..we would have to observe that and obviously we can not. We do know however that they were used in intraspecific fighting as we do have at least some Smilodon specimens with what appear to be canine inflicted puncture wounds, though I have to admit that sample size of individuals having those wounds being so small I don't think we can say for certain if this was something that was happening in regular basis or whether it was just freak accident. of course when you are in life and death situation you will use everything you have and think later. such wounds appear to be far more common in nimravids which is interesting.
Overall it all makes me think if we have actually heavily underestimated the strength of the teeth. We tend to make the assumption that theyr fragile but I'm not sure if it's ever been studied how much punishment those teeth can actually take.

As for protecting I think it had all it needed with damn long curved root going deep inside the skull as well as all the overlying muscle and skin and fur covering it. I think it was safe enough.

*2) Such claim would need some studies to back it up. I personally have never heard of study that had concluded that larger IOF would directly correlate with lip size. Would love to hear if there was such study. Would also love to see some figures how much larger the sabertooth IOF was compared to modern big felids. quick google image search glance appears to say not much.
Certainly there isn't correlation between higher innervation and size of an organ. otherwise we would look like the sensory homunculus.

Ville Sinkkonen said...

*3) The problem lies in that we just don't have anything like Smilodon around. Most of the sabertooths tend to be armed with the moderate size canines that can be seen for example in homotherines. They barely if at all extend beyond the mandible, and as you said tend to be comparable in length to those of clouded leopard. In clouded leopard they appear to be long enough to produce visible bulge in lower lip. I don't think this differs significantly from what would have been the case in moderate sabertoothed carnivorans. As the sabers grew through ontogeny the teeth pushed against the lower lip and the gum and tissues being adaptive formed small dimple or pocket where the canine fit snugly. This tends to be the case in living carnivores. Moderate sabertooths just took it just a bit further.
For smilodon such arrangement seems unlikely. maybe in it's case the canine pushed beyond the margin of lower lip causing visible droop on the lip line as it did so.

I don't see any problem of the relatively tiny bit of the canine that was hanging below the mandible. After all we have things like water deer and other sabertoothed ruminants that do just fine with well exposed canines. No lubrication needed.
Where does the argument that teeth need to be moist all the time come from anyway? Just curious. even if the keeping the teeth moist was necessary general production of saliva and gravity would take care of taht in any case. besides the liquid isn't just flowing in the surface of the tooth it's inside it's whole structure.

One last thing regarding droopy lips in domestic breeds. Yes they can do that and many other unfortunately detrimental things thanks to the fact that we have relieved them from all the natural stresses and pressures that they would be normally under. There's probably a very good reason why no such droopy lips exist in any living wild canivoran.

Warren JB said...

"How dare you compare sabertooth lips to the lips of artificially selected dogs and cats? Stop it."

I don't think your problem is in having a dissenting view (as I've said, it's why I'm here) - it's that you can be needlessly antagonistic about it. Given my comment about tyrannosaur lips, I suddenly find myself tied into a strawman comment, and wondering if I'm expected to be swayed by it.

But nope, not gonna stop thinking that bloodhounds aren't a great analogy for tyrannosaurs! Sabretooths are a slightly different prospect, but I'd still side with Dr. Day and Ville's final comment. Demonstration of plasticity is one thing, but the main purpose of some dog breeds - barely able to walk or breathe - seems to be demonstration of how rubbish humans can be at manipulating or imitating selection pressures on that plasticity.

Still looking forward to the next post, though!

D-man said...

I asked Spinosaurus the fisher what he thought of your post. He said that it is likely that the lips covered the canines like you said, though he did say the the lips looks more deliberate than natural in your artistic rendition of a Smilodon.

Also, since he have carnivorans down, how would sparrasodonts, hyeanodontids, gorgonopsids, and therocephalians protect them? The first 2 are not related to cats and the last 2 are not even true mammals at all, so would their canines be protected. Also, when you say they can srcunch up their lips to reveal their sabers to inflict the killing blow, does this mean that when they snarl, they would resemble those "old" reconstructions with baring teeth, and one final note, what would the face look like in side view with this form?

David Marjanović said...

The one problem I see is that Smilodon & friends are the only saber-toothed carnivores that lack matching bone flanges on the lower jaw. Thylacosmilus shows that length isn't a problem; Homotherium has them; so why are they absent in Smilodon?

Where does the argument that teeth need to be moist all the time come from anyway?

Teeth do apparently become brittle when they dry out. That's why ivory from forest elephants is considered higher quality than that from savanna elephants.

However, they obviously can't demineralize from contact with air!

D-man said...

Um, Duan, I think your Hellhound Rex hypothesis has been wrecked.

So they theropods in general probably did not have mammal or even lizard lips, but something more in line with bird skin lips.

Duane Nash said...

OK D-man last chance before I just start deleting your comments for straying too far off topic. You could have just posted this comment on the post it pertains to. I was at SVP 2015 and I disagree with Tracy's interpretation of the foramen. If the skull was tight skinned and croc like why would the foramen take a pronounced dip along the lower jaw that lines up precisely with where the longest teeth from the upper jaw penetrate? And if his tactile faced scenario is true why would there not be a more random skew of foramen along the whole head but instead the consistently line up in a manner that suggests they were providing innervation and blood flow to something? Finally Ford casts a very wide net when he characterizes theropods as rugose skulled. Some were more than others and it is very far from settled how much you can infer the amount of soft tissue on the skull from rugosity. Abelisaurids certainly would suggest a more tight fitting skin but other theropods have much less rugosity.

D-man said...

Oh, sorry, did not think I was straying off topic (seeing how this has to pertain to lips).

Robert Haan said...

Umm DUane ? i think its a little too early(pun intended) to refer to Ric Flair as the "late" great "Nature Boy".

Yet another well thought out post, i have no opinions of my own to add but i will say that BullDog Smilodon actually comes of as a rather handsome design.

Duane Nash said...

Damn *edit* I just get confused with all the ol' school 'restlers biting the dust lately. I could have sworn Ric Flair was one of 'em but just got confused.

Robert Haan said...

I don't blame you, alot of them have.

khalil beiting said...

Great job as always Duane! Sorry I haven't been vocal online with you recently like I used too. I've been so busy with school I don't have much time. But from what I've learned from your posts on Tyrannosaur and Smilodon lips, they make perfect sense. That's why you are my favourite researcher, simply because you turn speculative/fantastical ideas into a reality (or at least a likely reality) by giving large amounts of evidence and examples in favour of your new theory. Before reading your "Bulldog Rex" post, I always just assumed that it had Komodo Dragon-esque lips, and would have never dreamed of having something similiar to the lips of a domestic dog, let alone mammals in general on good ol' Rexy. But of course, you give a perfectly sound arguement in favour of such a feature. Now I can't get those fallpy Rex lips off of my mind whenever I think about it (in a good way of course). And I've had a problem with Smilodon teeth for years, seeing as how it doesn't make sense for a terrestrial Synapsid to have it's teeth showing like that. Tusks and harden combat teeth like Walrus' aren't a good example in this case, seeing as how they are structurally different to a degree and far different in oveerall use, so I was always stumped on what was going on with those giant saber teeth. But you just reminded me about what the far more likely feature that was going on. Now I have a question for you pertaining to lips. What do you personalyl think is the more likely oral structure on the mouths of Ornithischian Dinosaurs? I.E. Ceratopsians, Hadrosaurs, etc? Which one do you think they had out of these choices?:
Fully lipped:
Half lipped like Turtles:
or no lips?:
Or is it something else? Or do you not really no for sure? At this point in time, you are pretty much the lip master of Paleontology ;)

Duane Nash said...

Thanks khalil I am glad my ideas resonate with you. So often people, including many I respect, are closed off to new ideas or ways of thinking about things. We are indeed in a strange place in paleontology where there is a bit of a push/pull between the "hard" science and quite practical and informed speculation... Indeed I have seen many dismiss me as "speculative fun" or "take him with a grain of salt" or my favorite "too awesomebro". However we'll see who gets the last laugh...

No please don't call me the lip master, I don't want to be the master at anything except maybe the master at asking the >right questions<. With regards to ornithischians I have been pulling further and further away from obligate "cheeks" because i think we should differentiate cheeks from "lips" i.e. fleshy structures that border the mouth as opposed to those that close off the oral region.

I have to give credit where credit is due Larry Witmer points out that inset tooth rows are not so dramatic in fleshy cheeked mammals and Jaime Headden was very prescient in pointing out that the need for closed cheeks in ornithischians was always just asserted but never proven. For now I will say "lips" yes but "cheeks" at least as we interpret them now, I am leaning towards not quite or at least very different. Hint Panapolosaurus.

Stay tuned... and I apologize in advance for not being able to pump these out fast enough as my job is just killing me now but future posts will astound you I promise you this!!

khalil beiting said...

Wow. I don't understand why people would be so rude and dismisive to you when you clearly back up your claims with large quantities of evidence and examples. How dare they try and label you as anything close to the likes of David "photoshop" Peters. And I think the remark of "awesomebro" is hilarious seeing as how you try to ground things within reality.

Another reason why you are my favourite is because you do far more research than any other professional. The most vocal/active researcher besides you is arguably Mark Witton, yet he doesn't produce anything "stunning" (well, as of late that is). I don't mean to put him down or anything though. He's a great man who has (in part) revolutionaized the field of Pterosaurology. But what I mean is that he hasn't theorized anything stunning like you have. The importance of facial display in various "fighting" Dinosaurs, turning Plesiosaurs from cannon fodder to brutal ocean predators that out classed Mosasaurs, "neck boobs" and bulldog "lips" on the suprisingly mammalian Tyrannosaurus rex, "dump truck" Ankylosaurs, thermoregulation in Archosaurs without feathers (which deserves MUCH more research in proffesional literature), more support in favour of the mud crawling, tidal roamer Spinosaurus, vulturine Allosaurus, etc.

Ah sorry I wasn't nesecarily talking about cheeks in particular. I'm kind of just saying it in laymen terms, because when I say cheeks or lips, I'm refering to any form of facial integument. From wattles and lips to quills and horns. So then what is most likely then? Do you know of any pictures/artwork that represent what you think is most likely?

Sam Fritz said...

Hi, I'm new, and probably uninformed and not qualified to comment here, but the lips in your reconstruction look really floppy like a bulldog, while modern big cats tend to have more muscular, rounded coverings of their canines. I don't really know if this was the case for saber-tooths, and I agree that their fangs should be covered, but probably with more tiger like coverings, rather than a bulldogish floppy covering. If you considered this and there's a reason why you didn't portray it this way, please let me know. Thanks!

Duane Nash said...

@khalil yeah I try to abstain from getting into pissing contests with other researchers. Hey I do things the way I want to and if that means I get less exposure because I want to control how my thoughts, research and art is disseminated then that puts me in a position where I am looked at with suspicion because of "lack of peer review" then I got to eat my lumps. Peer review falls short again and again as I have exposed many times on this blog. I see scientific research moving into a more open, transparent, and collaborative method where numerous people: lay, professional, and multidisciplinary have a voice and input. In short science will move into a more progressive and open realm and I do foresee some push back from career academics.

Not to mention the modern academic peer reviewed paper is possibly the most mind numbing and robotic sounding piece of literature devised except for an IKEA instructional pamphlet.

@Sam Fritz I thought about this but as I mentioned in the post it really was hard to cover the canines and not have it look like a bulldog. Plus I aesthetically like the bulldog look for its jarring look so I went with it instead of trying too hard to make it look" catty". There is some liberty the artist can take in this manner,

@David Marjonovic I would surmise that in Smilodon which was at an extreme range in sabertooth predators for tackling large, tough, and combative prey that having bony projections hanging off of your mandible would be selected against. Extremely tough, elastic, and rugged skin flaps would most likely cover the lower aspect of the tooth from the mandible.

Nathaniel Emerson said...

Andrea Cau posted on theropod lips:

The key point is that teeth that are covered by lips have a different morphology than those that are exposed.

Anonymous said...

concerning the possibility that prehistoric people would choose to represent lionesses rather than lions: they were hunters and knew enough about lions to see it's the female that does the hunting.

David Marjanović said...


No. :-) I notice you didn't get Panoplosaurus right either.

I would surmise that in Smilodon which was at an extreme range in sabertooth predators for tackling large, tough, and combative prey that having bony projections hanging off of your mandible would be selected against.

More so than having teeth hanging off of your maxilla?

Anyway, I'll wait for the Reisz & Larson paper. :-)

they were hunters and knew enough about lions to see it's the female that does the hunting

That actually varies somewhat between different lion cultures. In some places, males hunt the bigger, more dangerous prey (think cape buffalo) and, IIRC, end up contributing 50 % of the pride's food.

Anonymous said...

I'm sorry, but I don't really agree. Something about that just seems, off.

Stevie Moore said...

I'm not sure if this is going to show up as I'm having trouble viewing the link. It should be a Lipped Thylacosmilus; "" I suspect that despite their popular image as bare-toothed killers, sabre-toothed mammals had extensive lips covering their upper teeth as well. Here is the famous sabre-toothed marsupial Thylacosmilus, looking more like the pot-bellied, funny-faced...

I suspect that despite their popular image as bare-toothed killers, sabre-toothed mammals had extensive lips covering their upper teeth as well. Here is the famous sabre-toothed marsupial Thylacosmilus, looking more like the pot-bellied, funny-faced death-wombat that it probably was.""

LeonelSaberTooth said...

Hello, ive read the whole thing,
About the topica you have been covering, first of all, if they did have long lips which cover the fangs it would be, like the comments above, very biteable. Second of all in order for the cat to expose his canines to bite anything it would need the lips to have muscles in them, if muacles were built in the lips it will be seen in the skull (skull shows where muscles touched it) and based on my ressarch no skull indicates this kind of lips. Another reason which i can't really explain is that it will simply be too heavy, and the lips would need to change the whole anatomical structure of the head and snout muscles to support their weight. You have mentioned something about teeth that chew and slice meat need to be covered with saliva, most articles claim that smilodon didnt use his upper fangs for eating at all, that is why hia incisors and other teeth need to be so large as well, he probably only used his canines to kill prey. Another suggestion is that the fangs were constantly licked (yes, licked) with the saber cat tongue to keep them wet, much like some lizards lick their eyes conatantly.
Correct me if i am mistaking and sorry for bad english, have a good day and thanks for reading :)

Related Posts Plugin for WordPress, Blogger...