Tyrannosaurus rex vs. Giganotosaurus carolinii

[Runic]

If it can't open its mouth that wide, then I'd really have to wonder how it went by eating a Triceratops.

Tyrannosaurus rex bite marks have been found on the fossilized bones of Triceratops horridus, but so far such fossils have been studied in an isolated manner. In new research, scientists worked on numerous specimens from MontanaÂ’s Hell Creek Formation to identify the tooth marks of T. rex and how it ate T. horridus.

The scientists presented their findings at the Society of Vertebrate Paleontology last week in Raleigh, North Carolina. In total, they found 18 specimens that had teeth marks. None of the bones showed any signs of healing, indicating that the bites were inflicted on dead animals as they were in the process of being consumed.

The bite marks included extensive puncture and pull marks on the neck frills on some of the specimens. The pulling action was probably not indicative of being eaten, but a repositioning of the prey. It suggests that T. rex was trying to get at the nutrient-rich neck muscles.

This is probably the easiest way to pull the head off, explains Denver Fowler, from the Museum of the Rockies in Bozeman, Montana. T. horridus‘ occipital condyles had teeth marks as well. They could have only been made if the animal had been decapitated.

This work shows the value of incomplete specimens and large samples for interpreting palaeobiology, states Andrew Farke, paleontologist at the Raymond M. Alf Museum of Paleontology in Claremont, California. There were precise, even delicate bites, along the front of several T. horridus skulls, suggesting that the nibbles were done on the meaty part of the face.

This led Fowler to question whether the feeding behavior of T. rex changed as the animals grew. With thick teeth, adult T. rex would have been well-suited to tear apart T. horridus, whereas juveniles may have had to rely on different feeding strategies to avoid damaging their teeth.

scitechdaily.com/how-tyrannosaurus-rex-ate-triceratops-horridus/

[Grey]

There's an obvious and not unsignificant size difference between Sue's skull and Stan's.

[theropod]

In Hartman's restoration, not in the usually listed and mounted and probably the one that was used in Bates & Falkingham. Shartman restores the specimen with a shorter and less massive postorbital region, reducing the overall size somewhat.

I don't know which is accurate, but that's irrelevant to the results unless the study independently modified their model in the same way (since the model was a scanned skull mount), which it doesn't seem to do. Like this, their skulls are nearly identical in size.

Yup, the Model they used is oversized compared to Hartman's restoration, so is the mounted skull. It seems to have been enlarged by reconstruction, similar to MOR 008. It also shows a similar underbite.

This means the bite force may actually be overestimated (proportionally) for this specimen not only due to the overestimated general skull lenght but also the increased bulkiness of the whole cranium.

More likely stan's cranium is indeed smaller than sue, but that rather means stan was overestimated than that sue would be even stronger.

BTW where's the bite force estimate for Giganotosaurus (misspelled Gigantosaurus) they cite even from? I couldn't find a paper in their list whose title made any mention of non-Tyrannosaurine theropods, neither is the name mentioned anywhere else, but it is marked as cited.
Also, is it reliable, considering how low the cited value for T. rex right next to it also is?
for now I'd really prefer to base an estimate on results from the same study if someone feels it is really necessary to make bite force estimates for the carcharodontosaur.

[Grey]

Tom Holtz about the claims of average sizes and so-called likelihood of Giganotosaurus being larger (private com) :

Consider that to a modern biologist, even the Tyrannosaurus sample is woefully small to say anything about statistical ranges of body size. So yes, all we can say is which one has larger *known* individuals, not which one is larger as such.

Nuff said.

Tom Holtz about the bite force estimate relative to Stan's skull :

Sue's skull is larger. So yes, it is likely that it would be even stronger, although hard to say without doing the analysis how much more powerful.

It is likely Sue had a higher bite force than 3.5-5.7 tonnes.

[Deleted]

Sept 24, 2013 17:09:38 GMT 5 Grey said:

It is likely Sue had a higher bite force than 3.5-5.7 tonnes.

Based on scaling alone, it should be higher, but not by much - the ranges would overlap massively.



Larger version (to see the measurement numbers more clearly)

I measured the lower jaw/mandible, since it's actually the one that exerts force, the upper jaw is fixed to the skull and cannot move.

Let's assume that the width disparity is the same as the length disparity, which assumes that FMNH PR2081 has a mandible ~107.4% the width of that of BHI 3033.

The mandible of FMNH PR2081, then can be calculated as being ~1.28 times the volume and mass of the mandible of BHI 3033.

(~1.46 meters / ~1.36 meters) * (~42.7 centimeters / ~38.4 centimeters) * (1.074) = ~1.28152

Strength scales by the cross-sectional area which goes up by the square, so we must get the cube root of this number, which is ~1.0862, then square it to get ~1.179822.

To get FMNH PR2081's likely bite force:

Lower bound: ~35 kN * ~1.179822 = ~41.2938 kN
Upper bound: ~57 kN * ~1.179822 = ~67.2499 kN

We get the range of ~41.29-67.25 kilonewtons for the bite force of FMNH PR2081.

---

But this doesn't constitute a major advantage, slicing bites can be very potent and should not be assumed to be less deadly. A good bite from Giganotosaurus can slice important tendons and muscles.

It all boils down to this: Both theropods are rough equals at size and formidability.

I wonder why is it so hard to accept Tyrannosaurus and Giganotosaurus being equals. The Tyrannosaurus fanbase twists the meaning of shartman's words and analysis to fit their view, and insist on the "crushing bite is deadliest" fallacy, while the Giganotosaurus fanbase keeps using the upper bound, ~108% of holotype dimensions(making MUCPv-95 around ~13.5 meters long), as if it were the only possible size of MUCPv-95.

[theropod]

Those are both the upper figures from the study and for anterior and posterior ends of the toothrow, they do not consitute a lower and upper bound.

Whether sue's bite would be significantly stronger than what has been calculated in Bates and Falkingham remains to be seen, since it depends on the skull restoration. I have heard the suggestion it may be, but due to generally underestimated numbers. Either way I can live with sue's bite force being somewhat stronger.

There would be nothing wrong with using Stan to represent T. rex' size tough.

[wiffle]

Sept 23, 2013 21:44:46 GMT 5 theropod said:

No, it only cites a single figure, which should not be compared to the extremes of the range of error given for T. rex, if used at all since it's potentially an incompatible figure like the cited estimate for rex also is.

So because it does not have a range, we should not use it?

It's currently the only tested data we have, and as of yet I have not seen researchers dispute it.

Which all are suggestive of a proportionally greater bite force in Giganotosaurus carolinii than in Allosaurus sp.

If anything, Giganotosaurus' skull looks less robust and more elongated. The increased gape doesn't help.

Firstly, we'd have to get a hold of Therrien et al. and look whether it's accurate or makes wrong assumptions like Meers did for example.

Secondly, the result would not be too different. Assuming Giganotosaurus had a 3t bite as based on Allosaurus, and Daspletosaurus approximately the same (which appears somewhat liberal considering Giganotosaurus has an at least 50% longer and at least significantly deeper skull), that of T. rex would be roughly 2 times stronger.

Tyrannosaurus Rex is the only species of its family that has a skull so well suited for high bite forces. Tarbosaurus' is also quite robust but nonetheless less massive.

I cannot see how their accuracy would need any improvements, they rarely miss their target and are absolutely on par with mammalian carnivores that have binocular vision.

This is not really comparable due to the difference in their hunting styles and the strategies involved in this fight. Also, note that both reptilian predators do retain some degree of binocular vision.

Sure.

So if Tyrannosaurus can still move that quickly with conservative neck muscle estimates, then how much faster is Giganotosaurus, really?

It is consensual (Bakker, 1998; Rayfield et al., 2001; Antón et al., 2003; Snively et al., 2007; snively et al., 2013) to have been used as a killing tactic, by pushing the upper jaw into prey or striking at it to then pull and rip out pieces of meat.

Already noted. Hatcheting is nevertheless a more lengthy process even if the strike is quicker, as it requires 2 steps to execute.

Btw Giganotosaurus displays hypertrophied neural spines in the pectoral area, very much alike those of a bison or entelodont. those are also structures associated with neck muscle origins. It does not have a weak neck at all, rather a pretty strong one.

I do not see much difference in that region.

yes, feeding bites left huge ghashes on a robust pelvis. I would consider the horns that were actually bitten off more impressive feats tough, since ghashes or scratches in bones are found even in non-crushers (eg. Allosaurus). This is what makes me think in the case of T. rex pull bites were primarily feeding-techniques.

Allosaurus doesn't leave large puncture wounds in bone.

It can be expected a Giganotosaurus when given the bite force of a T. rex would be in serious trouble, so would a T. rex with that of a Giganotosaurus be, because both their jaws show different specializations and both wouldn't work properly and would even be endangered by their respective hunting styles. a 6t bite would possibly be too much for a Giganotosaurus' mandible, and that of Giganotosaurus may not be sufficient to withstand the stresses excerted during holding onto struggling prey animals with such a heavy jaw.

A stronger bite force gives a greater range of possible values to choose from. An animal with a stronger bite force can produce a weaker bite, but an animal with a weaker bite force can't produce a stronger bite.

The difference is irrelevant. If I cut off a leg this ends the fight just like breaking the neck. And if I cut the throat, it does too, there is no notable difference in the effect this has.

In the case of a cut throat, blood loss will be quick and tremendous and blood will flow from the brain as well as the heart. The restult is a brain without oxygen and a circulatory shock, both are life-threatening conditions, and both will start taking effect immediately.

If you've listened to Dr. Vincent Di Maio during the American Zimmerman trial, you'll know that even the destruction of the heart allows someone to remain conscious for 10-15 seconds. This was not something just made up to support court case; it's been known for a while that gunshots to the heart, while almost certain to prove fatal and extremely debilitating, nevertheless do not put down an aggressor instantaneously. Mr. Di Maio was probably exaggerating when he implied that the body could function just as well for those few seconds, but he was absolutely correct when he claimed that someone would still be able to move/talk/stand/etc.

No, Never heard of him. Anyway, would he have been able to fight in these few seconds? I think we both know the answer.

There's actually a video of it online. He was fully capable of self-locomotion for at least a couple of seconds despite the fact that he was bleeding all over the place. Would he be able to fight as well? After the first few seconds, likely not. This does not mean he wouldn't have been capable of reacting if he wanted to.

There are several incidences of neck injuries in hockey. Richard Zednick was able to skate to help after getting his carotid cut:
en.wikipedia.org/wiki/Richard_Zedn%C3%ADk

Chickens often run around after being decapitated, does that mean they could fight the butcher?

If they are still alive and not simply acting on nerve impulse, yes.

Yes, it is Durable. So are other theropods.

A specimen of Allosaurus has a traumatically injured and completely deformed mandible, and it survived too. There's a Sinraptor skull showing evidence of a devastating face bite. All of these are definitely very durable. Countless other pathologies are reported from various theropods (Allosaurus, Mapusaurus...), even tough those are not immediately associable with intraspecific fights and may result from hunting.

While disfiguring and possibly disabling, face mutilation is not generally fatal. On the other hand, animals that take a massive tooth to the braincase are often not so (un?)lucky.

No, but soft tissue will logically offer much less resistance to them (them being sharper), meaning they'll more easily damage it, instead of just moving it, than comparatively blunt ones. It is for this reason a knife to the stomach will be more devastating than a club, even if the club impacts with far greater force.
The knife will cause deep, penetrating injuries and slice through tissues. The club will only cause bruises because the soft-tissues will be moved and displaced to a good extent.

A club is not simply going to cause bruises. Blunt force trauma to the abdomen can damage organs (even if it's something as simple as a punch) and cause internal hemorrhaging. In fact, the shockwave from an explosion is simply a compressed wave of air moving at high velocities, and therefore also constitutes blunt force.

Furthermore, a club has no points upon which pressure is concentrated. Being hit with a mace would be more analogous to a T. rex bite.

The same also applies to a bite, it will not be comparable in terms of how devastating it is to soft tissue if it is blunter, because blunt trauma is the ideal tactic for damaging bones and a few, delicate structures that are not resistant to compressions (central nervous system, brain, some internal thoracic organs), not for attacking the majority of resistant soft-tissues which need application onto a sharp edge to be damaged effectively.

Blunt force trauma frequently damages the small intestine, so no.

Again, the teeth are not that sharp, they'd push them aside or compress them mostly (you cannot crush a blood vessel, and the big ones are not that delicate), without doing big tissue damage to the soft materials. You can frequently observe a similar condition in cat bites, they leave only minor superficial injuries but puncture the spinal medulla, or they grab the trachea to suffocate a victim, without injuring any of the vital structures in the region.

It is possible to rupture blood vessels through compression alone. Even if they are not broken, the constriction of blood flow can easily prove fatal.

Big cats don't have a bite that is proportionally much stronger than a Tyrannosaurus's; the Tiger's bite force barely outranks the bull shark's anterior jaw pressure, and is about 11% lower than the Great Hammerhead's. Keep in mind that this is contrasting the minimum point of pressure of the sharks' jaws (anterior) to the maximum of a Tiger's (canine point). When you add in the fact that the prey or victim's body structures are stronger pound-for-pound, you can see why there is relatively little damage to flesh outside of what is directly punctured.

If you really doubt Tyrannosaurus' ability to damage such tissue, think about an elephant with a bunch of spikes on its butt sitting on Giganotosaurus' neck. That should clear it up right quick.

Unless with a lot of luck, it will slide in between. The teeth will piece through the material and crush the spine without inflicting major injuries to the exterior tissues. Mostly they will leave puncture wounds, not huge exanguinations.

Tyrannosaurus' teeth may move a small amount of muscle tissue aside, but they will not physically shift massive neck arteries and veins. Furthermore, the teeth are quite tightly packed, seemingly more so than Giganotosaurus'.

img12.imageshack.us/img12/3597/gigavsrex.jpg

Note also that a bite to the head from Tyrannosaurus will be crippling, whereas the same scenario vice-versa will produce nasty but non-fatal flesh wounds.

The teeth would quite easily eviscerate the musculature on top, going deep is no problem. I don't see Great white sharks having any problem biting much deeper than their teeth are long, otherwise they would hardly bite dolphins or seals in two or easily amputate human legs, not to mention be able to bring down whale calves and elephant seals.

A shark's teeth will cut out a portion of flesh as they chomp down, akin to a cookie-cutter. Giganotosaurus' bite could do that, but to a reduced extent.

In Triceratops' case Tyrannosaurus has a major height advantage, enabling it to reach the dorsal surface which ought to be more convex, but of course it would preferably bite the skull or neck to deliver the killing blow, and perhaps it would have simply attacked in pairs, one disabling the hindlimb.

How does it go about eating the side and body then? You don't seriously expect such a huge predator to be so inefficient.

These are also tremendously strong arms we are talking about.
A body slam needs acelleration of a multi-ton body, enough to come free from another multi-ton body securing it with massive meathooks, and until then, it's already too late. If it is just pulling backwards slowly it cannot built the momentum it needs, and it's opponent could just step forward, following it's movements.

They might be strong, but they are not very large relative to body size. The arms would likely have difficulty in this matter.

Well, since Giganotosaurus is definitely the taller animal (tough perhaps slightly),

That depends on what specimen you use. There are also some large fragmentary remains of Tyrannosaurus that people have postulated to belong to Tyrannosauruses of questionable lengths.

Because it's a 7t Theropod, it isn't going to charge at an opponent at it's top speed in a fighting situation.

Why?

Both will never reach their maximum speeds unless they take a decent amount of time to accellerate.

^

Are you suggesting most, if not all Tyrannosaurus specimens show injuries related to intraspecific fights?

I'll have to look into that.

No, I'm not, I think it's totally irrelevant actually.

A stronger bite force is not going to do Giganotosaurus any harm. This is common sense. You can point to examples of extant animals with effective bites that don't require a strong bite force, but the same animals would almost certainly be hindered if their ability to drive their teeth through flesh were reduced. Referring back to the cookie cutter example, you're not going to be able to slice out chunks if you can't put much strength behind them.

I assume the cited value may not be in the slightest comparable to the values produced in the studies, just like the value for T. rex is also far off. I hence prefer, if you have the urge to compare bite forces, to do so accurately.

The previous Tyrannosaurus bite force estimate was Erickson's, which likely grossly underestimates T. rex's bite force given that it is based on a feeding bite. We don't have any such fossil records of prey for Giganotosaurus.

If the hippo has long knifes, that it will tear through my flesh with, at whatever it's using to sit on me, I'd take my chances with another elephant, even if the other elephant has some railroad-spikes.

Would you, really? If I were an elephant, I would take the hippo any day of the week.

It's not sure at all how much larger/smaller than average these figures are. Anyway, since they are obviously wrong, why are we even discussing them?

Because you can still convert the Meers study to legitimate results.

Just to demonstrate you cannot scale a theropod bite force up from mammalian carnivores, which should be clear anyway!

The study also included reptilian predators.

It can do the same to a theropod no matter what side the latter is attacking. In the back, there's a tail and the rear legs, at the side, it can lie down on it, body-slam or kick laterally and may also reach it with the tail or neck depending on where it is...

A sauropod attempting to fall over on an assailant would be suicide. Presuming it can even get up afterwards, it will most likely have hurt itself. That's like jumping off a building in an attempt to crush someone by landing on them.

Lateral kicks would most likely be ineffective due to the sauropod's joint system, just as an elephant will not do serious damage in the same manner. Body-slamming would depend on the sauropod's ability to shift its weight around, which I am guessing is not all that good.

That's just the pose Hartman gave them, it's called artistic freedom. Frankly, that seems to be a trend in the world of art, tough I have seen few accurate restorations of large carcharodontosaurs to even compare with.

Come on. You don't even need a drawing for that. Just look up images of the 2; Giganotosaurus' neck is lateral in nature and is mostly straight.

Well, it makes no note that Tyrannosaurs would either, and doesn't compare them.

Persons does in another study. I don't see him making references to carcharodontosaurid cursoriality anywhere however.

Giganotosaurus actually does have an adaptation for eating smaller prey, although I doubt it is of any relevance:

the point of the mandibula was reinforced to this purpose with a "chin" and broadened to handle smaller prey.[15]

sauropods aren't sluggish

What?

Besides, I'm already agreed the latter are more cursorial and perhaps have a higher top speed. This just doesn't have anything to do with agility and is of little relevance for fighting situations.

Most of Tyrannosaurus' prey were quadrupedal and of a similar size. Such an animal would naturally demand a greater degree of agility to catch.

The hip muscles should also be able to power side movements of the leg muscles more effectively, and the greater tibia length covers more distance per step when turning.

The method of speculating on locomotor abilities only based on, likewise hypothetised, mobility of the prey will very likely lead to wrong assumptions.

It doesn't take Einstein to figure out that sauropods are slower than hadrosaurs and ceratopsians.

what he was not considering is that the lenght is for the most part just thin tail,=little weight=low RI, and that T. rex, while a bit more compact, has a big, bulky thorax and a very heavy head/neck area that would have increased it's RI considerably.

Considering the caudofemoralis study, the tails of theropods were likely quite bulky to accommodate the muscle.

I don't see how centering the weight is supposed to reduce turning rate. Undoubtedly the head is quite heavy, but it is at least pneumatized to take some of the weight off, and the neck muscles should prevent it from swinging it around too much when turning.

I adressed the arcometatarsus on other occasions, it adding anything to agility is an as of yet (and despite several papers done on it) untested hypothesis. It has been demonstrated, if I'm not mistaken, the structure is comparatively robust and yet elongate-again, that suggests cursoriality but has nothing to do with agility.

There is a study on it, called "The subarctometatarsus: intermediate metatarsus architecture demonstrating the evolution of the arctometatarsus and advanced agility in theropod dinosaurs". Unfortunately this must be purchased.

Snively's study, which I'm sure you've seen:

Another possibility is that the tensile keystone
morphology conferred heightened agility for a given
body mass. As such, the arctometatarsus may have
been broadly analogous to the stiffened tails of
dromaeosaurid coelurosaurs (Ostrom, 1969), which
have been suggested as dynamic stabilizers. Because there was no anteriorly propulsive component
to the elastic rebound of ligaments, third metatarsal
constriction did not directly avail increased speeds.
Instead, the unifying and shear-resisting properties
of the arctometatarsus may have absorbed forces
involved in linear deceleration, lateral acceleration,
and torsion more effectively than the feet of other
theropods. These forces are limiting factors to combat performance in humans (Snively: pers. obs. in
open hand and weapons sparring) and the arctometatarsus may have imparted momentarily excessive construction (Gans, 1974) for selectively crucial
behaviors, such as predation or escape.

The paper does note that this is an untested hypothesis, but it does explain why the arctometarsus might be useful for agility.

[Grey]

Sept 24, 2013 20:06:00 GMT 5 @brolyeuphyfusion said:

I wonder why is it so hard to accept Tyrannosaurus and Giganotosaurus being equals. The Tyrannosaurus fanbase twists the meaning of shartman's words and analysis to fit their view, and insist on the "crushing bite is deadliest" fallacy, while the Giganotosaurus fanbase keeps using the upper bound, ~108% of holotype dimensions(making MUCPv-95 around ~13.5 meters long), as if it were the only possible size of MUCPv-95.

I accept Tyrannosaurus and Giganotosaurus being roughly equal but I see Tyrannosaurus as a more direct and brutal predator/fighter.
As for twisting Hartman's words, I've seen the contrary as well.

A possible outcome I've once reported is that Sue would kill first MUCPv-95 but would die soon afterward of massive exsanguination.

[theropod]

So because it does not have a range, we should not use it?

No, that's not what I wrote. I meant you should not compare it to the upper end of the range given for T. rex.

And yes, of course there's a good chance of the figures not being interchangeable in the slightest. Yoou'd need a study analysing both for that. Like this, it ain't even clear whether the figure is for an anterior or posterior bite, and what skull restoration it bases on.

So if you feel the need to compare their bite forces because you think this would be important, you have to be cautious.

I only recall the suggestion of T. rex' bite being ~2-3 times as powerful, more seems to be a stretch.

It's currently the only tested data we have, and as of yet I have not seen researchers dispute it.

I've not seen it being tested, I haven't even see where it's from. Again, that wasn't my point.

If anything, Giganotosaurus' skull looks less robust and more elongated. The increased gape doesn't help.

Allosaurus seems to show the most extreme adaptions towards gape among known theropods, and has a comparatively short temporal opening as an adaption for this.

Tyrannosaurus Rex is the only species of its family that has a skull so well suited for high bite forces. Tarbosaurus' is also quite robust but nonetheless less massive.

Tarbosaurus' skull is more similar to that if Allosaurus in terms of it's width (which is the most notable thing that's "robust" in tyrannosaurine skulls). Daspletosaurus' is significantly broader than T. bataar, and likely the closest to T. rex there is in this regard.

If you assume T. rex would have bitten noticeably stronger than it's smaller analogy, the same should be done with Giganotosaurus (because it has a larger temporal fenestra with less paralell muscle fibres and a likely broader skull), but again, that's pointless speculation.

This is not really comparable due to the difference in their hunting styles and the strategies involved in this fight. Also, note that both reptilian predators do retain some degree of binocular vision.

Who said that?

So if Tyrannosaurus can still move that quickly with conservative neck muscle estimates, then how much faster is Giganotosaurus, really?

I doubt they are conservative.
Sorry, confused something. The definition of conservative varies and most other theropod neck restorations are also conservative by the same standards as Snively & Russel 2007 (whose own work I rely on).

Already noted. Hatcheting is nevertheless a more lengthy process even if the strike is quicker, as it requires 2 steps to execute.

There's a variety of ways to augment a bite by ventroflexion, and they all will be at least as quick or quicker to execute than a bite from T. rex.

The skull can be placed just like in a traditional bite but with the bulk of the power coming from the neck-that will act just like a normal bite except for a more prominent tearing motion likely being involved.
The whole neck and skull can also strike at an opponent, which is just a single motion as opposed to placing the jaws and biting down in a classic bite.

Eventually both will probably be quicker considering the skull doesn't have to be such a massive structure.

I do not see much difference in that region.

Look at Hartman's skeletals you already posted.

Allosaurus doesn't leave large puncture wounds in bone.

Large ghashes on a Camarasaurus ilium and bitemarks on big numbers of sauropod bones are being attributed to it. This is a kind of injury you frequently see, from various predators, including eg. lamniforms. The occasional deeper punture, or, as I mentioned, large horns bitten off are a different story and imo better examples than feeding-ghashes on bones.

A stronger bite force gives a greater range of possible values to choose from. An animal with a stronger bite force can produce a weaker bite, but an animal with a weaker bite force can't produce a stronger bite.

That's totally irrelevant if the stronger bite force is not usable because it would threaten the jaws, and if the big muscle mass makes the skull too heavy and the gape too small.

If you've listened to Dr. Vincent Di Maio during the American Zimmerman trial, you'll know that even the destruction of the heart allows someone to remain conscious for 10-15 seconds. This was not something just made up to support court case; it's been known for a while that gunshots to the heart, while almost certain to prove fatal and extremely debilitating, nevertheless do not put down an aggressor instantaneously. Mr. Di Maio was probably exaggerating when he implied that the body could function just as well for those few seconds, but he was absolutely correct when he claimed that someone would still be able to move/talk/stand/etc.

There is not much to move/talk/stand in a few seconds. And in these few seconds an animal may still live, it will not be in good health or able to free itself and strike back, the effects of the injury will already start to act on it.

Not to mention it would be in an infavourable position to do much anyway, the position it got bitten in in the first place.

While disfiguring and possibly disabling, face mutilation is not generally fatal. On the other hand, animals that take a massive tooth to the braincase are often not so (un?)lucky.

Had stan had serious brain injuries, it would have been dead. The tooth merely punctured the bones, which is certainly a painful and dangerous injury, but not more so than many others.

The face is an area with important muscles, nerves and blood vessels, and structures crucial to feeding and breathing. A bite can cause lots of trouble and surviving it is a feat of extreme durability. There's no difference between that and a puncture wound in the posterior cranium that was not fatal and hence must have failed to deal major damage to the nervous system.

A club is not simply going to cause bruises. Blunt force trauma to the abdomen can damage organs (even if it's something as simple as a punch) and cause internal hemorrhaging. In fact, the shockwave from an explosion is simply a compressed wave of air moving at high velocities, and therefore also constitutes blunt force.

Well, you certainly don't think T. rex' bite is an explosion.

The knife will be much more effective, that's it. A knife tearing through your guts will go deeper and cause greater damage with more immediate effects than a mace will, even if the latter may cause fatal hemorrhage later on.

The mace on the other hand will be more effective on your skull or spine.

Furthermore, a club has no points upon which pressure is concentrated. Being hit with a mace would be more analogous to a T. rex bite.

Well, then a mace.

Blunt force trauma frequently damages the small intestine, so no.

Certainly not as frequently as penetrating or slashing injuries do (relative to the number of occurrences of these injuries of course), but I was not referring to the intestine alone.

It is possible to rupture blood vessels through compression alone. Even if they are not broken, the constriction of blood flow can easily prove fatal.

Possible, but much more difficult than with a sharp application of force. Animals do not bleed to death from mere constriction, and tetrapods have several blood vessels for supply of each region for the exact purpose of providing a backup in case one is damaged or just constricted due to changing postures.
This was about actually causing damage, all that I'm arguing is that just like Giganotosaurus is inferior at damaging skeletal structures, Tyrannosaurus will be inferior at causing heavily bleeding lacerations and exanguinations of muscle and other tissue.

Big cats don't have a bite that is proportionally much stronger than a Tyrannosaurus's; the Tiger's bite force barely outranks the bull shark's anterior jaw pressure, and is about 11% lower than the Great Hammerhead's. Keep in mind that this is contrasting the minimum point of pressure of the sharks' jaws (anterior) to the maximum of a Tiger's (canine point). When you add in the fact that the prey or victim's body structures are stronger pound-for-pound, you can see why there is relatively little damage to flesh outside of what is directly punctured.

This was merely an analogy, but I cannot see what relevance the comparison with large selachians has. Apart from that, the canines are in the anteriormost part of the mouth. The carnassials do not cause major tissue damage either when they bite down (which is of coruse because they are not designed to do, their jaws are designed to punture the spinal medulla).

If you really doubt Tyrannosaurus' ability to damage such tissue, think about an elephant with a bunch of spikes on its butt sitting on Giganotosaurus' neck. That should clear it up right quick.

I doubt in that case the majority of the damage would be to the soft tissue, it would simply have a crushed spine and skull.

Tyrannosaurus' teeth may move a small amount of muscle tissue aside, but they will not physically shift massive neck arteries and veins. Furthermore, the teeth are quite tightly packed, seemingly more so than Giganotosaurus'.

Then I wonder why there appears to be no extant mammalian predator that kills by severing major arteries in the neck, and those that did (Machairodontids, some metatherians, nimravids) had special adaptions for effective slicing.

I would not rely on that skull cast, it's inaccurate. Giganotosaurus has a great number of sharp teeth along a long toothrow, which it will use like a saw especially to tear through these structures. T. rex has a shorter toothrow with thicker, blunter teeth that will punture and rip apart the bones, but they won't be very effective against soft, fibrous tissues.

btw the T. rex teeth are poking out too far from their sockets, more accurately, it should look like this:

mambobob-raptorsnest.blogspot.co.at/2011/10/tyrannosaurus-rex-skull.html

Note also that a bite to the head from Tyrannosaurus will be crippling, whereas the same scenario vice-versa will produce nasty but non-fatal flesh wounds.

You mean ones severing important jaw musculature such as the pterygoideus, adductor mandibulae and others concentrated near the external surface of the skull or mandible base? That would also be crippling.

Btw crippling traumatic face injuries are not always deadly, and certainly not instantly so.
www.thehindu.com/multimedia/dynamic/00908/CB31_CROCODILE_G0C4_908521e.jpg

Does this mean they do not decide a fight? Do you think a Giganotosaurus with a bitten-off snout or a T. rex with severed jaw musculature (or one with a severed neck musculature and throat) would have any capacity to fight left?

A shark's teeth will cut out a portion of flesh as they chomp down, akin to a cookie-cutter. Giganotosaurus' bite could do that, but to a reduced extent.

And why?

Sharks primarily cut out tissue by their sawing motion. Giganotosaurus probably did the exact same thing.

How does it go about eating the side and body then? You don't seriously expect such a huge predator to be so inefficient.

Biting the belly of a dead animal isn't the same as biting that of an alive one, especially if that dead animal already has bite wounds inflicted on it.

They might be strong, but they are not very large relative to body size. The arms would likely have difficulty in this matter.

Depends on what matter you assume.

Hold an accellerated T. rex pulling with a kinetic energy of 200 000 joules? Certainly.

Keeping the animal's relative position to a non-accellerated T. rex that on top of that has probably fatal injuries dealt to it's internal organs, central vascular system and/or musculature? No.

That depends on what specimen you use. There are also some large fragmentary remains of Tyrannosaurus that people have postulated to belong to Tyrannosauruses of questionable lengths.

And this was already assuming the largest in ~40 individuals as compared to the larger in two, so I wouldn't claim this comparison to be unfair...

Why?

Because it takes time to reach it, that's physics. Do you think an elephant could accellerate to 40kph in a second?

A stronger bite force is not going to do Giganotosaurus any harm.

It's not gonna do it any good, it cannot use a stronger bite force.

This is common sense. You can point to examples of extant animals with effective bites that don't require a strong bite force, but the same animals would almost certainly be hindered if their ability to drive their teeth through flesh were reduced.

But it isn't reduced, that's the point. A Tyrannosaurus would also be hindered if it's bite force was reduced.

There are and were animals with sharp teeth and low bite forces that nevertheless have the ability to do large amounts of damage to prey or opponents. This is a fact.

T. rex having a more potent bite is entirely speculation without a proper thing to base it on. In fact, all modern examples demonstrate this never seems to be the case.

Referring back to the cookie cutter example, you're not going to be able to slice out chunks if you can't put much strength behind them.

You can, sharks do it by sawing (enabling Galeocerdo to saw in two turtles). You don't need a powerful bite force to do lots of damage.

The previous Tyrannosaurus bite force estimate was Erickson's, which likely grossly underestimates T. rex's bite force given that it is based on a feeding bite. We don't have any such fossil records of prey for Giganotosaurus.

Do we have any biomechanical analyses of the skull? I'm not aware of any.

No, a feeding bite is not necessarily representative of a killing bite. Which shows the cited numbers are not necessarily compatible. They are definitely not with their estimate for Allosaurus, which is an indication.

Would you, really? If I were an elephant, I would take the hippo any day of the week.

What a luck you aren't an elephant.

Because you can still convert the Meers study to legitimate results.

No, you can only make it look as if you could. Allometric scaling of extant mammalian bite forces to T. rex' body weight to estimate it's bite force is pure hogwash.

The study also included reptilian predators.

Probably not many, since most extant terrestrial predators are mammalian. And those reptiles that were included must have been monitor lizard and crocodiles, the former (or, funny enough, at least macrophagous ones, those that actually rely on machanical damage inflicted by their jaws) having comparatively low and the latter extremely high bite forces, causing the regression to slope upwards immensely.

A sauropod attempting to fall over on an assailant would be suicide. Presuming it can even get up afterwards, it will most likely have hurt itself. That's like jumping off a building in an attempt to crush someone by landing on them.

Lying down on a theropod is no suicide. Elephants would have no problem doing the same, and it is unlikely a Sauropod would not be able to use it's body weight to crush something as long as it isn't laying down for a long time, just lowering it's body.

Lateral kicks would most likely be ineffective due to the sauropod's joint system, just as an elephant will not do serious damage in the same manner. Body-slamming would depend on the sauropod's ability to shift its weight around, which I am guessing is not all that good.

Exactly, you are guessing, that guess leading you to assume sauropods were easy prey.

Come on. You don't even need a drawing for that. Just look up images of the 2; Giganotosaurus' neck is lateral in nature and is mostly straight.

"lateral in nature"?
What images of the two do you mean if not Hartman's?

Persons does in another study. I don't see him making references to carcharodontosaurid cursoriality anywhere however.

Why does he have to? Because you think that Carcharodontosaurs not being as cursorial as Carnotaurus means T. rex was a more agile animal when there is no direct relationship between both?

Again, Carnotaurus is a theropod nearly uniquely adapted towards speed. Firstly, that's not what we see in either T. rex or Giganotosaurus, secondly, nothing ever suggested that, and thirdly, that T. rex has large hemal arches does not mean other theropods automatically didn't just because that's not mentioned when they being referred to sporadically regarding the ecology of Carnotaurus.

According to Bates et al. 2012 the positive allometry in Persons & Currie is likely for the most part due to the low overall weight estimate they assumed for BHI 3033. Also, Hutchinson et al. 2012 produced much lower caudofemoralis-masses for the specimen.
That T. rex had more well-developed caufofemoralis (or hindlimb-musculature in general) at weight parity remains a highly questionable hypothesis. It is entirely conceivable that they are actually quite comparable (especially considering the modeling for Acrocanthosaurus is made quite conservative due to the oddly angled chevrons in the laserscan which should actually point more downward than backwards and thus might anchor larger muscles than restored).

Giganotosaurus actually does have an adaptation for eating smaller prey, although I doubt it is of any relevance:

the point of the mandibula was reinforced to this purpose with a "chin" and broadened to handle smaller prey.[15]

That's an adaption for handling stresses induced by struggling prey (which would supposedly be small because there's no reason Giganotosaurus' jaws would have to be in contact with a large, struggling animal for more than a few seconds). By the same logic, T. rex is even more well suited for doing that.

Besides, it is of course a fallacy to assume either only fed on large to gigantic animals.

What?

Sauropods aren't sluggish. That is, unless you call elephants sluggish.

Most of Tyrannosaurus' prey were quadrupedal and of a similar size. Such an animal would naturally demand a greater degree of agility to catch.

See the next point.

The method of speculating on locomotor abilities only based on, likewise hypothetised, mobility of the prey will very likely lead to wrong assumptions.

It doesn't take Einstein to figure out that sauropods are slower than hadrosaurs and ceratopsians.

That is not related to the agility required for hunting them. If the sauropods were running away, it may tell you how fast the hunter must have been, that's all.

The hip muscles should also be able to power side movements of the leg muscles more effectively, and the greater tibia length covers more distance per step when turning.

The shorter femur also provides a smaller lever arm for the hip muscles to act on for moving the leg, which would be disadvantageous for torque.

And the largest T. rex has a tibia that's 2cm longer than that of the smallest Giganotosaurus. That won't make a huge difference at all (unless you call 2cm notable in a 12m animal).

Considering the caudofemoralis study, the tails of theropods were likely quite bulky to accommodate the muscle.

Near their base, or at least along the proximal part, not near their tips. The main mass of the M. cf is proximally.

I don't see how centering the weight is supposed to reduce turning rate. Undoubtedly the head is quite heavy, but it is at least pneumatized to take some of the weight off, and the neck muscles should prevent it from swinging it around too much when turning.

My point is that the head is heavy, it has to be because it had to bite onto struggling prey. Of course it won't swing around as if it were made of clay, but it, the big torso and the thick neck are big weights that are not at all concentrated near the center, but the exact opposite.

It's not centering the weight, it's merely distributing it differently as to be heavier relative to lenght. The carnosaur is the animal with the weight likely shifted further towards the hips due to its lighter craniocervical and anterior thoracal region.

The paper does note that this is an untested hypothesis, but it does explain why the arctometarsus might be useful for agility.

Yeah, I know the paper. There are also equally untested reasons why it may be disadvantageous, eg. it provides smaller lever arms and less friction on the ground and for the tibiotarsus to control the weight and the less kinetic structure (while I'm quite confident it increases running efficiency and thus top speed) may act in the same way as walking on a stilt, by not adapting to the ground as much and actually reducing, not increasing, the stability during weight shifts.

Again, this needs testing and until then is far too frequently brough up.

All that we really know it enhances is cursoriality, which alone does not imply better agility.

this is the abstract of the other paper:

The subarctometatarsus is a plesiomorphic form of arctometatarsus. Five individual subarctometatarsalian specimens are examined in this study including Microraptor gui, Sinornithosaurus millenii, Sinovenator changii, Sinovenator sp. and Sinornithoides youngi. Bivariate analysis illustrates a closer relationship between subarctometatarsalians and small theropods possessing the plesiomorphic theropod metatarsus (e.g. Compsognathidae and Archaeopteryx). Reduced major axis (RMA) analysis supported this conclusion but also indicates a distinct statistical difference between the three categories of theropod metatarsus. Additionally, development of the subarctometatarsus is inferred to have been linked to advanced cursoriality as implicated for the arctometatarsus. Structural similarity between the subarctometatarsus and the arctometatarsus portrays a common mechanical function of being able to withstand the forces of high impact with the substrate. Phylogenetic analysis reveals five independent origins of the arctometatarsus.

As I already predicted, it speaks of cursoriality, not agility. But the studied structure was not the same as that Tyrannosaurines posess anyway.

[theropod]

A possible outcome I've once reported is that Sue would kill first MUCPv-95 but would die soon afterward of massive exsanguination.

How would massive exanguination (eg. a mauled flank or neck) from a Giganotosaurus leave it in a condition to fight back? A single successful bite from either of the two means instant "game over" for any similar-sized animal, injuries inflicted would be too severe for any struggle afterwards.

[Grey]

Exsanguination does not provok immediate neutralization, even to the neck, at least not as quickly as a bone-splattering bite.

[creature386]

Sept 25, 2013 18:05:42 GMT 5 theropod said:

So if Tyrannosaurus can still move that quickly with conservative neck muscle estimates, then how much faster is Giganotosaurus, really?

I doubt they are conservative.

Uhm, why?

Under conservative assumptions, radial accelerations of the head by large superficial muscles (M. transversospinalis capitis, M. complexus, and M. longissimus capitis superficialis) enabled rapid gaze shifts and imparted high tangential velocities to food sufficient for inertial feeding.

www.bio.ucalgary.ca/contact/faculty/pdf/russell/305.pdf

[Deleted]

Sept 25, 2013 12:48:47 GMT 5 Grey said:

Sept 24, 2013 20:06:00 GMT 5 @brolyeuphyfusion said:

I wonder why is it so hard to accept Tyrannosaurus and Giganotosaurus being equals. The Tyrannosaurus fanbase twists the meaning of shartman's words and analysis to fit their view, and insist on the "crushing bite is deadliest" fallacy, while the Giganotosaurus fanbase keeps using the upper bound, ~108% of holotype dimensions(making MUCPv-95 around ~13.5 meters long), as if it were the only possible size of MUCPv-95.

I accept Tyrannosaurus and Giganotosaurus being roughly equal but I see Tyrannosaurus as a more direct and brutal predator/fighter.
As for twisting Hartman's words, I've seen the contrary as well.

A possible outcome I've once reported is that Sue would kill first MUCPv-95 but would die soon afterward of massive exsanguination.

It really depends on who gets the first bite. A well-placed bite from Tyrannosaurus/Giganotosaurus to the neck or on important joints/tendons would leave Giganotosaurus/Tyrannosaurus critically wounded and in no condition to fight.

[theropod]

Sept 25, 2013 18:50:18 GMT 5 Grey said:

Exsanguination does not provok immediate neutralization, even to the neck, at least not as quickly as a bone-splattering bite.

There would be no noticeable difference, and certainly not the time for an effective counterstrike. Saying T. rex could still kill an opponent after suffering injuries of such a kind is whishful thinking. It´s a very odd hypothesis too-it assumes a Tyrannosaurus even after suffering fatal (and usually immediately incapacitating) injuries could still muster the strenght and speed needed to kill a very formidable opponent, or otherwise, that this opponent is so incredibly weak it would be killed even by a mortally wounded foe.

A bite would destroy not just the blood flow to and from the brain but also likely big parts of the neck musculature and cause rapid shock due to the bleeding and lacking vagal stimulation. There is no reason to favour the effects of a bone-shattering bite, in which the action itself would probably take longer already.

[gigadino96]

Sept 24, 2013 20:06:00 GMT 5 @brolyeuphyfusion said:

Sept 24, 2013 17:09:38 GMT 5 Grey said:

It is likely Sue had a higher bite force than 3.5-5.7 tonnes.

Based on scaling alone, it should be higher, but not by much - the ranges would overlap massively.



Larger version (to see the measurement numbers more clearly)

I measured the lower jaw/mandible, since it's actually the one that exerts force, the upper jaw is fixed to the skull and cannot move.

Let's assume that the width disparity is the same as the length disparity, which assumes that FMNH PR2081 has a mandible ~107.4% the width of that of BHI 3033.

The mandible of FMNH PR2081, then can be calculated as being ~1.28 times the volume and mass of the mandible of BHI 3033.

(~1.46 meters / ~1.36 meters) * (~42.7 centimeters / ~38.4 centimeters) * (1.074) = ~1.28152

Strength scales by the cross-sectional area which goes up by the square, so we must get the cube root of this number, which is ~1.0862, then square it to get ~1.179822.

To get FMNH PR2081's likely bite force:

Lower bound: ~35 kN * ~1.179822 = ~41.2938 kN
Upper bound: ~57 kN * ~1.179822 = ~67.2499 kN

We get the range of ~41.29-67.25 kilonewtons for the bite force of FMNH PR2081.

---

But this doesn't constitute a major advantage, slicing bites can be very potent and should not be assumed to be less deadly. A good bite from Giganotosaurus can slice important tendons and muscles.

It all boils down to this: Both theropods are rough equals at size and formidability.

I wonder why is it so hard to accept Tyrannosaurus and Giganotosaurus being equals. The Tyrannosaurus fanbase twists the meaning of shartman's words and analysis to fit their view, and insist on the "crushing bite is deadliest" fallacy, while the Giganotosaurus fanbase keeps using the upper bound, ~108% of holotype dimensions(making MUCPv-95 around ~13.5 meters long), as if it were the only possible size of MUCPv-95.

You're right, both were equivalent in size, but I do not think it's a good thing to compare the ability of the two animals.

Think: one was made ??to kill Sauropods or large prey in general, while one was made to kill prey equipped with armor. So you can not compare the abilities of these two animals, both evolved for different purposes. I think this is about a 50/50. Both were about the same size, each had its weaknesses and its strengths.