Tyrannosaurus rex vs. Giganotosaurus carolinii

[wiffle]

A skull being able to withstand producing a certain bite force is not always going to be able to take it in return, hence why tanks don't blow themselves up when they fire. When biting into something, the force is spread out, whereas when being bitten the pressure is concentrated into very small points.

If Tyrannosauruses produce a bite force of 35,000-57,000 newtons, and you say that a skull capable of producing a bite force can also take the attack in return, we would not have any damaged skulls at all.

[creature386]

Sept 22, 2013 7:04:46 GMT 5 wiffle said:

By the way, there is a paper what claims Tyrannosaurus' bite force to be 18,3-23,5 t (this is no joke). For comparison, the highest estimate for Megalodon is 18,2 t.
I would like to know where they get such figures from.

It was obtained from scaling up extant carnivores. The ratio was likely off; the bite force for a 5 ton Tyrannosaurus would have been in the range of 5.6-9 tons. If you take into account the new mass estimates, this would be the bite force of a 6.4 ton Tyrannosaurus.

Grey already replied to my question. Anyway, the bite force of Tyrannosaurus is debatable, IMO estimates range from 3,1-9 t. For now, I would take the newest estimate (3,5-5,7 t).

[theropod]

You realize they tested it for skull strength, right?

First of all, the article notes that was a result from other scientists from the tyrell museum. I'd like to know where it is published and what it is based on before taking it as a fact.

Tyrannosaurus had numerous adaptations for resisting as well as transferring bite force:

Undoubtedly that's true.

So we are required to skew data in favor of Giganotosaurus now?

No, you just aren't supposed to do that in favour of T. rex, that's the point.
Why are you using the upper bound for T. rex, is there any rational reason to suppose we should do so in that case but not assume the same assumptions will also increase whatever bite force we take for G. carolinii.

It is simply not logical to assume the upper-bound estimate of T. rex corresponds to the only cited (and by comparison extremely conservative!) figure for Giganotosaurus in terms of conservatism/liberalism.

Why would scaling an Allosaurus up produce accurate figures for Giganotosaurus' bite?

Because that's their own estimate and not one they just quoted, hence it is going to be more compatible with ntheir estimates for T. rex. Assume Giganotosaurus had a skull (conservative) lenght of 1.6m, this gives it a bite force of 3.1t. That's only about half T. rex', but not as weak as you are trying to make it.
Allosaurus based on it's morphology should give conservative estimates.

That's because your brain fills in the rest to create a 3D image. The fact that some predators don't have excellent binocular vision is a far cry from saying it does not help.

It is apparently not that important, that's all. My brain cannot accurately something not given to it by the eyes.

Larger neck bones offer more muscle attachment and can support both them and the skull more easily.

Those exact larger bones also take up a lot of space were the neck muscles would otherwise be. Of course Those of T. rex have larger processes at the same neck lenght, which again, largely just serves to support a heavy skull on a short and robust neck.

Of course it does. A dinosaur with a bite force of 20,000 pounds is going to do far more damage than one with a bite force of 2,000 pounds.

That's just a far too common superficial observation the like of "the animal with the bigger bite force has the better bite"

One question, whom would you favour, a Great white shark or a crocodile that has a bite force that's about 2 times as strong (knowing at the same time the crocodile is 3 times smaller).

There are none, but they would still be in fighting condition for a small amount of time-as publicized by the Zimmerman trial, even a destroyed heart would still give someone about 15 seconds to react. Furthermore, a crushed and torn jugular, carotid, windpipe, and spinal cord will kill faster than a sliced jugular, carotid, and windpipe. If Tyrannosaurus is bitten of the neck, it still has a chance to take down Giganotosaurus with it.

There is absolutely no way after a throat bite from a potent slicer T. rex would have the ability to fight back, that's it. A single bite would kill immediately either way.

T. rex would have far smaller chances of cutting the blood vessels and musculature than Giganotosaurus, since it would require another level of action to do it, just like Giganotosaurus would have a smaller chance of severing the spinal chord.

A Tyrannosaurus tooth was lodged in Sue's rib, so yes, it is possible. The back is also a possible target if Tyrannosaurus rears up.

Sure? I could find no mention of that. Btw it even appears the interpretation of sue's facial holes as bite marks was very premature and media hype, these may have been abscesses...

Several abnormalities in the skeleton have attracted popular attention. There is no defensible evidence for bite trauma
on the skull, but the rib cage does show evidence for healed fractures. Lesions on the right scapulocoracoid and
humerus coincide with fractured ribs on the right cervical-dorsal transition and may indicate a single trauma to the
right side of the body. The left fibula is pathological, but may not have been fractured. Two fused tail vertebrae may
preserve natural molds of the tail muscles.

Some of the damage on the left side has been interpreted in
the popular media as evidence for a bite wound from another
tyrannosaur (Glut, 2000; Hanna, 2000; Larson, 2002). There is
no conclusive evidence in support of this idea, and although
there are shallow circular depressions on the left squamosal,
they are not regularly spaced and do not immediately suggest
bite marks.

Entry of dentary teeth into these openings is clearly vis-
ible in the CT sections (Fig. 16), as these were generated before
the jaw was removed. These are the only demonstrable bite
marks on the skull, and were self-inflicted.

Brochu, 2003

Which doesn't explain how Giganotosaurus can get within range to use them in the first place.

You just wrote the back was a potential target for T. rex if it reared up. Don't you think Giganotosaurus also had the ability to do so at least as easily, consiering it's height and lenght and the fact that it's arms are in a good position to be used in that case?

Of course it does. Is it easier to move out of the way of a jet plane or car?

The speed of the animal that is dodging, not of a projectile. Also, I doubt in close-quarters there will even be a notable difference, no jet-vs-car situation.

I said that bite force and speed are relevant and you said that antelopes don't win against lions. Thus I would infer that you are claiming the antelope has an advantage in both respects.

No, I was just speaking about the speed. There are many other examples for bite force.

Mammalian tactics are often irrelevant in a giant theropod fight, and the wolf's bite hasn't crossed into the immediately disabling territory.

Then how do you know T. rex' has?

Of course Mammalian tactics are not applicable here. Still, you seem to assume the stronger bite automatically ensures victory, which is simply a myth.

It does mean they don't fight each other as often. Experience counts.

No, it means T. rex is one of the theropods with the biggest sample size, so our likelyhood to find evidence for intraspecific fights is far greater. And yet, we also find unambigous evidence in Sinraptor, an animal known from 3 times fewer specimens, and many injuries in Allosaurus that could be attributable.

I was not saying that Tyrannosaurus would be just as effective as hunting a sauropod. What I was saying was that if Giganotosaurus's bite force was higher, that would not harm its ability to hunt.

I was just giviing you an example why it would.

If Giganotosaurus had the bite force of T. rex, it's craniodental morphology would have to become similar to that of T. rex, so woult it's abilities. You cannot seperate those points, just like you cannot give a heron the bite force of a snapping turtle.

If a Tyrannosaurus bit the same portion of leg, it would also pierce, tear, and crush connective tissue and muscle. It need not crush bone to do harm. 

It definitely needed more time to do so either way. of course, with some time it could also rip off the meat. But you have to understand the reasons why I'd rather get clubbed in the stomach than stabbed.

As has been previously pointed out, no.

I fear we have a disagreement here.

The bite force in the Meers study was for a 5 ton Tyrannosaurus.

And there was a time when 5t was a perfectly reasonable size estimate for a specimen like Stan, whose skull is sue-sized and among other things used in the Falkingham study, as you pointed out.

If Tyrannosaurus missed, Triceratops would likely mount a quick counterattack. T. rex can't just run away.

The same would be the case with a sauropod, it's not a defenseless giant sheep that wouldn't defend itself. It's swiping range is tremendous, so is it's power. It could virtually kill a Theropod with more or less any body part. That's not something that to attack is any less dangerous than a Triceratops.

No, I meant to say decapitate, as in To slice someone's head off." A bit of purposeful hyperbole, I suppose, but the point is that Komodo dragons do not shear off limbs without some time and effort.

That's because they don't have to do so.

Apparently that did not matter.

That paper doesn't compare it to other theropods, just say it could move it's head quickly. I cannot see the relevance of that point which I never doubted.

That is Snively's 2007 study.

That is why I wrote the OTHER Snively et al., 2007.
I was referring to
Functional Variation of Neck Muscles and Their Relation to Feeding Style in Tyrannosauridae and Other Large Theropod Dinosaurs

And its efficiency? How much energy is lost from the strike? Tyrannosaurus had fused nasals that allowed it to impart the force to the prey without losing much of it in the process-Giganotosaurus did not possess this feature.

Bite force estimates already account for this, Allosaurus also had unfused nasals. The highly kinetic cartilaginous jaws of Carcharodon carcharias are stated to be only a minor impediment to excerting strong forces, and at the same time they reduce the stresses on the jaw.

Btw the claim that Tyrannosaurid nasals were stronger is technically untrue, as the study explains).

The study notes that the increased caudofemoralis mass would have enhanced agility. This muscle was particularly large in Tyrannosaurus.

Allometrically, because there were no similarly large theropods for comparison, just smaller coelurosaurs (Gorgosaurus libratus and Ornithomimus edmontonicus).

I think nobody doubts Ornithomimus is a much more agile and faster animal than a Tyrannosaurus, it has proportionally smaller muscles because it is smaller and doesn't need them. The same applies to Gorgosaurus, a T. rex needs allometric increase in muscularity to counteract, at least to some extent, it's greater weight. If there was a Gorgosaurus or Ornithomimus the same size as T. rex, those would probably have even bigger m. C. l.

This has no influence of the comparative Caudofemoralis muscle sizes of T. rex compared to other giant theropods, those were not compared to it in that study and never studied in that regard as far as I know.

[creature386]

Sept 22, 2013 15:49:45 GMT 5 theropod said:

One question, whom would you favour, a Great white shark or a crocodile that has a bite force that's about 2 times as strong (knowing at the same time the crocodile is 3 times smaller).

34 kN is the maximum possible bite force for a 6,7 m crocodile, such a crocodile wouldn't be three times smaller.

[theropod]

1.8t is also the maximum bite force for a 3.3t Great white. That for a 2,5t (perhaps a more probable weight) specimen is merely 1.5t.

But of course I was speaking roughly. More precisely, a great white that's 2,5 times the size of a crocodile bites only with 52% of the strenght. And this does by no means tell us it has by any means the less dangerous bite or is the slower killer.

Concluding this for one taxon by comparison of Giganotosaurus' and Tyrannosaurus' bite forces will lead to erraneous assumptions.

[wiffle]

Sept 22, 2013 15:49:45 GMT 5 theropod said:

First of all, the article notes that was a result from other scientists from the tyrell museum. I'd like to know where it is published and what it is based on before taking it as a fact.

The 200,000 newton bite force was from Tyrrell museum, not the skull strength. The study itself does not appear contradict it, given that the comment about the bite force is not disputed.

No, you just aren't supposed to do that in favour of T. rex, that's the point.
Why are you using the upper bound for T. rex, is there any rational reason to suppose we should do so in that case but not assume the same assumptions will also increase whatever bite force we take for G. carolinii.

We should not be taking the lowest estimate either.

Because that's their own estimate and not one they just quoted, hence it is going to be more compatible with ntheir estimates for T. rex. Assume Giganotosaurus had a skull (conservative) lenght of 1.6m, this gives it a bite force of 3.1t. That's only about half T. rex', but not as weak as you are trying to make it.
Allosaurus based on it's morphology should give conservative estimates.

You realize this is exactly why the Meers 183,000-235,000 newton study was flawed. Animals get weaker pound-for-pound as their size increases.

It is apparently not that important, that's all.

Given that people retain 3D vision constantly, I doubt they would know the importance without losing an eye or something.

Those exact larger bones also take up a lot of space were the neck muscles would otherwise be. Of course Those of T. rex have larger processes at the same neck lenght, which again, largely just serves to support a heavy skull on a short and robust neck.

They may take up more space but they also offer more muscle attachment and support for both the muscles and the neck.

Once again, have you ever seen an animal with a thick & weak neck? If so, would its situation be improved by thinner vertebrae?

That's just a far too common superficial observation the like of "the animal with the bigger bite force has the better bite"

One question, whom would you favour, a Great white shark or a crocodile that has a bite force that's about 2 times as strong (knowing at the same time the crocodile is 3 times smaller).

Crocodiles don't have efficient weaponry for killing large prey without a death roll or drowning, both of which would be difficult to use against a shark. Tyrannosaurus' teeth on the other hand work perfectly fine.

There is absolutely no way after a throat bite from a potent slicer T. rex would have the ability to fight back, that's it. A single bite would kill immediately either way.

Only damage to the central nervous system is immediately incapacitating.

T. rex would have far smaller chances of cutting the blood vessels and musculature than Giganotosaurus, since it would require another level of action to do it

Actually, a simple bite down without any tearing motions would have an equal chance. Not only are those blood vessels large, but the teeth still cover similar area. If you stabbed some railroad spikes into someone's neck, they would have just as much of a chance of hitting something vital as if you stabbed a bunch of knives into someone's neck instead. The pressure from the bite itself would also be capable of rupturing blood vessels and crushing the trachea.

just like Giganotosaurus would have a smaller chance of severing the spinal chord.

Teeth are only going to go in so far, and the spinal cord is protected by the neck vertebrae.

Sure? I could find no mention of that.

Hmm, I can't find any either. Regardless, Tyrannosaurus should still be able to bite the chest where it curves into the belly.

^Any of the boxed areas should be fair game from a frontal approach.

You just wrote the back was a potential target for T. rex if it reared up. Don't you think Giganotosaurus also had the ability to do so at least as easily, consiering it's height and lenght and the fact that it's arms are in a good position to be used in that case?

I never disputed that Giganotosaurus couldn't use its arms if it were reared up, and I said that this would be the only way it could put them to use in earlier posts. This would be a slower process however and, given the distance between Giganotosaurus' head and arms, may make a bite more difficult to execute.

Also, now that I look at it, Tyrannosaurus doesn't really need to rear up after all:

The speed of the animal that is dodging, not of a projectile. Also, I doubt in close-quarters there will even be a notable difference, no jet-vs-car situation.

If Tyrannosaurus charges, that leaves less of a window to dodge or counterattack.

Then how do you know T. rex' has?

That study noted Tyrannosaurus' bite would be equivalent to a medium sized elephant sitting on something. Combined with the teeth, it's going to kill quite quickly.

Still, you seem to assume the stronger bite automatically ensures victory, which is simply a myth.

I said that a stronger bite force is not going to be a bad thing, and Tyrannosaurus' weaponry is more useful against a similarly sized theropod.

No, it means T. rex is one of the theropods with the biggest sample size, so our likelyhood to find evidence for intraspecific fights is far greater. And yet, we also find unambigous evidence in Sinraptor, an animal known from 3 times fewer specimens, and many injuries in Allosaurus that could be attributable.

This doesn't say anything about Giganotosaurus.

If Giganotosaurus had the bite force of T. rex, it's craniodental morphology would have to become similar to that of T. rex, so woult it's abilities. You cannot seperate those points, just like you cannot give a heron the bite force of a snapping turtle.

Say Giganotosaurus had enough muscle to increase its bite force by 500 pounds. This would not harm it.

It definitely needed more time to do so either way. of course, with some time it could also rip off the meat. But you have to understand the reasons why I'd rather get clubbed in the stomach than stabbed.

Would you rather have a hippo with knives on its feet stand on you, or an elephant with railroad spikes stand on you?

And there was a time when 5t was a perfectly reasonable size estimate for a specimen like Stan, whose skull is sue-sized and among other things used in the Falkingham study, as you pointed out.

Bite force data compiled for extant predators (crocodylians, carnivorans, chelonians and squamates) are used to establish a relationship between bite force and body mass among extant predators. These data are used to estimate the maximum potential bite force of T. rex, which is between about 183,000 and 235,000 N for a bilateral bite. The relationship between maximum prey body mass and predator body mass among the same living vertebrates is used to infer the likely maximum size of prey taken by T. rex in the Late Cretaceous.

I doubt they tested for a specific specimen of Tyrannosaurus. They simply scaled it with body mass.
Sue at the time was thought to be around 7 tons, and is now believed to be 9 tons. This is an increase of about 29%. 5x1.29=6.45, therefore this bite force range would apply to a Tyrannosaurus of about 6.45 tons.

The same would be the case with a sauropod, it's not a defenseless giant sheep that wouldn't defend itself. It's swiping range is tremendous, so is it's power. It could virtually kill a Theropod with more or less any body part. That's not something that to attack is any less dangerous than a Triceratops.

It's a lot slower and the tail only has so much reach. The front sides are exposed and could be attacked with less peril.

That's because they don't have to do so.

And they're not going to slice off huge slabs of flesh with a single bite either.

That paper doesn't compare it to other theropods, just say it could move it's head quickly. I cannot see the relevance of that point which I never doubted.

So is there anything to suggest Giganotosaurus would strike as quickly other than a lighter skull?
Tyrannosaurus' neck is also more s-shaped and curved, which should allow it to extend further and possibly gather more momentum when lunging.

That is why I wrote the OTHER Snively et al., 2007.
I was referring to
Functional Variation of Neck Muscles and Their Relation to Feeding Style in Tyrannosauridae and Other Large Theropod Dinosaurs

This was comparing it to Ceratosaurus and Allosarus, and I did not see anything saying that neck muscles were not particularly large. It also notes that they were well-adapted to the puncture-and-pull feeding strategy, which should allow Tyrannosaurus to tear flesh much more easily.

Bite force estimates already account for this, Allosaurus also had unfused nasals (again, those also have their advantages in absorbing stresses. Btw the claim that Tyrannosaurid nasals were stronger is technically untrue, as the study explains).

Apparently they were.
www.ohio.edu/people/es180210/Snively%20pdfs/snively_nasals.pdf

Allometrically, because there were no similarly large theropods for comparison, just smaller coelurosaurs (Gorgosaurus libratus and Ornithomimus edmontonicus).

From Persons's study of Carnotaurus:

The development of interconnecting caudal ribs, each with a strong dorsal inclination, enabled an exceptionally large M. caudofemoralis. This would have made Carnotaurus sastrei a powerful sprinter – perhaps among the fastest of the large bodied theropods (see Fig. 7). Consideration of these morphological differences in a stratigraphic context indicates a pattern of increased caudofemoral mass and cursorial potential throughout the evolutionary history of the Abelisauridae of South America. During at least the early portion of this history, abelisaurids coexisted with another clade of predatory dinosaurs: carcharodontosaurids. The carcharodontosaurids of South America (including Giganotosaurus carolinii, Mapusaurus roseae, and Tyrannotitan chubutensis) were among the largest of all theropods, and obtained body sizes much greater than that of any known abelisaurid [13]. It has been argued that the extreme size of these carcharodontosaurids allowed them to hunt the even larger South American titanosaur sauropods [34]. The cursorial tail morphology of South American abelisaurids may have arisen to help in avoiding potential carcharodontosaurid predators and/or supported niche partitioning by allowing abelisaurids to specialize in the pursuit and capture of smaller prey, such as ornithopods.

It seems to imply that carcharodontosaurids didn't have any special adaptations for caudofemoralis mass.

[theropod]

The 200,000 newton bite force was from Tyrrell museum, not the skull strength. The study itself does not appear contradict it, given that the comment about the bite force is not disputed.

Sorry, I meant the mandible strenght:

He noted that colleagues at the Tyrrell museum have shown that a T. rex's lower jaw could apply 200,000 newtons of force, or enough strength to lift a tractor-trailer.

We should not be taking the lowest estimate either.

No, we should take the mean estimate, as I wrote. That estimate may be underestimated, or maybe not, if so, that also applies to Giganotosaurus.

You realize this is exactly why the Meers 183,000-235,000 newton study was flawed. Animals get weaker pound-for-pound as their size increases.

I have not read the Meers study, but I did not scale up pound for pound, I of course did it properly, adjusting for the squared growth of muscular strenght.

While weight will increase with the 3rd power, strenght will just grow with the 2nd. In other words, if you assume an animal grows as much stronger as it grows heavier, you'll produce tremendous overestimates. I only took the skull lenghts (1.6/0.79) and took the square of that, which, again, will yield a conservative estimate adjusting for this.

I guess that greatly overestimated figure you mention perhaps simply based on some tremendously powerful bite in the extant world, disregarding not the square cube law but rather the functional morphology of each animal's jaw.

Given that people retain 3D vision constantly, I doubt they would know the importance without losing an eye or something.

Well, you can try it. It may be a bit of a difference, but it's not at all significant. Komodo dragons and crocodiles can both launch precise and quick strikes at their prey, without having a large field of stereoscopic vision.

Once again, have you ever seen an animal with a thick & weak neck? If so, would its situation be improved by thinner vertebrae?

Certainly not. I'm just saying you are overestimating how strong Tyrannosaurus' neck really was.
We can again use the komodo dragon as an analogy, it's bite is largely, if not mainly powered by a postcranial pulling motion. It's neck is significantly thinner relative to it's size than that of big cats, which don't really use their necks for much at all.

A longer and more flexible neck seems to be crucial for being effictively incorporated in the bite, just loike sufficient power. T. rex neck is thick to bear a heavy cranium with lots of adductor muscle. It's certainly not a slow striker, but very likely not as quick as a lighter-skulled theropod. I also want to remind you most of these Lighter-skulled theropods also seem to have considerable attachments and moment arms (especially Allosauridae, but also Ceratosauridae, Carcharodontosauridae, Sinraptoridae etc.), they are not necessarily weaker at all.
Again, in Giganotosaurus we face the problem of incomplete remains and even more incomplete documentation.

Crocodiles don't have efficient weaponry for killing large prey without a death roll or drowning, both of which would be difficult to use against a shark. Tyrannosaurus' teeth on the other hand work perfectly fine.

Based on what are you saying this? Here we enter the field of speculation.

Of course T. rex probably had a bite that on it's own was more effective than a crocodilians. And that's not the point actually.

The point is, that you are saying just because it has a higher bite force it has a better bite, frankly that's not true, I just demonstrated. We have no basis for assuming that.

Only damage to the central nervous system is immediately incapacitating.

No, lots of kinds of damage can immediately incapacitate an animal. Eg. sometimes it's enough to cut a tendon in one of the legs, and an animal will be helpless. A bite to the neck would cause devastating damage to the cervical musculature, which is crucial for placing bites-without it, an animal cannot strike back.
Again, cut major blood vessels and a cut nervus vagus will cause shock in a matter of seconds, which is equal in it's potency to a Tyrannosaurus crushing a spine.

Actually, a simple bite down without any tearing motions would have an equal chance. Not only are those blood vessels large, but the teeth still cover similar area.

But they are probably not sharp enough to cut through something by just touching it, such a bite would just cause the arteria and venes to be shifted. Only a powerful ripping motion would cause significant soft-tissue damage.

If you stabbed some railroad spikes into someone's neck, they would have just as much of a chance of hitting something vital as if you stabbed a bunch of knives into someone's neck instead. The pressure from the bite itself would also be capable of rupturing blood vessels and crushing the trachea.

Without a sharp edge, the likelyhood of severing something is not that great. It is for that reason you usually don't see victims of big cat or crocodile attacks bleeding to death in a reasonable amount of time. Most soft tissues are compressable without sustaining much damage, pressure alone doesn't rupture them that easily.

Again, I must say their bites in this area would have very similar effects, tough through different actions.

Teeth are only going to go in so far, and the spinal cord is protected by the neck vertebrae.

Neural arches are very thin bone and that's a massive saw. But as I said, it's chances of doing major damage on them are slim, just like T. rex' chances of severing the major structures of the throat or the musculature.

Hmm, I can't find any either. Regardless, Tyrannosaurus should still be able to bite the chest where it curves into the belly.

That's an only very slightly convex area, so I doubt that, especially that it could catch enough tissue in it's jaws and bite down hard enough to do notable damage. at best it would rip off a bit of skin and fascia.

I never disputed that Giganotosaurus couldn't use its arms if it were reared up, and I said that this would be the only way it could put them to use in earlier posts. This would be a slower process however and, given the distance between Giganotosaurus' head and arms, may make a bite more difficult to execute.

It won't be an initial attack unless in very rare cases, it will rather be a securing of the prey animal after it has been apprehended with the jaws, ie. it could hook into something after biting it in case the first bite doesn't kill immediately (such as with a bite to the thoracic/abdominal/pelvic/caudal regions).

Also, now that I look at it, Tyrannosaurus doesn't really need to rear up after all:

Sorry to say that, but those scales from Wikimedia are terribly inaccurate, the depictions are horrible, they aren't scaled correctly at all (because that happens to be very difficult), and even if they were, wouldn't objectively reflect their sizes.

If Tyrannosaurus charges, that leaves less of a window to dodge or counterattack.

It's accelleration wouldn't be quick enough to effectively charge at all, but again, the difference wouldn't be big, and what counts is not the maximum speed but the maneuverability and accelleration.

I said that a stronger bite force is not going to be a bad thing, and Tyrannosaurus' weaponry is more useful against a similarly sized theropod.

well, I highly doubt that's the case.

This doesn't say anything about Giganotosaurus.

Because we only have two specimens, one of which is just a dentary and the other one not even properly described. Would you really expect we'd have found bite marks on these two if the species showed great intraspecific agression?

Say Giganotosaurus had enough muscle to increase its bite force by 500 pounds. This would not harm it.

Neither would it help it. It would make it's gape slightly smaller, it's head slightly heavier and cause it's teeth to break a slightly more often, but neither is going to have notable effect, neither will a bit over 200kg of additional bite force have.

Would you rather have a hippo with knives on its feet stand on you, or an elephant with railroad spikes stand on you?

Both would easily kill me, it's completely indifferent.

Btw that has to be one big hippo, and one small elephant in your scenario.

I doubt they tested for a specific specimen of Tyrannosaurus. They simply scaled it with body mass.

Thanks, that quote makes a lot of things clear.

The reason the bite force turned out so high is simply that they treated it like some extant animal that's 5t in weight.
Now, extant predators tend to be mammals, mammals tend to be diphyodont, which causes them to usually have comparatively blunt teeth and high bite forces, increasingly high with increasing size and macrophagous tendency. If you calculate a relationship for them, it will of course greatly overestimate the bite force of T. rex, because shouldn't won't be any stronger than an isometrically scaled extant animal (and perhaps weaker, since it has no need for a downright absurdly strong bite), while these extant animals cause the regression line to display a significant slope.

Sue at the time was thought to be around 7 tons, and is now believed to be 9 tons. This is an increase of about 29%. 5x1.29=6.45, therefore this bite force range would apply to a Tyrannosaurus of about 6.45 tons.

Sue at it's liberal end is thought to be 9t. 7t is still a completely reasonable estimate for the lower one.

It's a lot slower and the tail only has so much reach. The front sides are exposed and could be attacked with less peril.

save for being kicked, crushed, toppled and/or trampled by an angry collossus rushing forward.

So is there anything to suggest Giganotosaurus would strike as quickly other than a lighter skull?

A lighter skull is enough to suggest this. In the modern world, animals with lighter skulls also tend to strike more quickly.

Tyrannosaurus' neck is also more s-shaped and curved, which should allow it to extend further and possibly gather more momentum when lunging.

All theropod necks are S-shaped.
Funny enough while basal tetanuran cervicals are opisthocoelous, those of coelurosaurs are amphiplathian, so one would expect the neck of Allosaurs to be more flexible (and in fact this was demonstrated for Allosaurus, see Snively et al., 2013).

That S. shape in T. rex is probably also supposed to be weight bearing in it's primary use, since the moment arm of dorsiflexive muscles will be better through that. The long neural spines will also limit flexibility.

This was comparing it to Ceratosaurus and Allosarus, and I did not see anything saying that neck muscles were not particularly large. It also notes that they were well-adapted to the puncture-and-pull feeding strategy, which should allow Tyrannosaurus to tear flesh much more easily.

They are primarily lateroflexive, and their ventroflexive power is rather small by comparison. Of course the strong dorsiflexors would have allowed powerful pulling motions while feeding, leaving traces such as those seen on the Triceratops pelvis/sacrum.

I don't see why from that not being refuted you assume they were particularly strong. After all, that's the claim that has to be supported.

You can see from their restorations other theropods also have large neck muscles, and especially allosaurs tend to have proportionally longer necks, so the comparison at neck-lenght parity will show the whole structure as smaller than it is.

Apparently they were.
www.ohio.edu/people/es180210/Snively%20pdfs/snively_nasals.pdf

I'm familiar with that paper.

The computed average strengths of Allosaurus fragilis nasals are
higher than those of the albertosaurine tyrannosaurids when
plotted against nasal length

The nasals are not stronger per se, but you are right in that their skull roofs are less kinetic and probably stronger structures.

From Persons's study of Carnotaurus:

The development of interconnecting caudal ribs, each with a strong dorsal inclination, enabled an exceptionally large M. caudofemoralis. This would have made Carnotaurus sastrei a powerful sprinter – perhaps among the fastest of the large bodied theropods (see Fig. 7). Consideration of these morphological differences in a stratigraphic context indicates a pattern of increased caudofemoral mass and cursorial potential throughout the evolutionary history of the Abelisauridae of South America. During at least the early portion of this history, abelisaurids coexisted with another clade of predatory dinosaurs: carcharodontosaurids. The carcharodontosaurids of South America (including Giganotosaurus carolinii, Mapusaurus roseae, and Tyrannotitan chubutensis) were among the largest of all theropods, and obtained body sizes much greater than that of any known abelisaurid [13]. It has been argued that the extreme size of these carcharodontosaurids allowed them to hunt the even larger South American titanosaur sauropods [34]. The cursorial tail morphology of South American abelisaurids may have arisen to help in avoiding potential carcharodontosaurid predators and/or supported niche partitioning by allowing abelisaurids to specialize in the pursuit and capture of smaller prey, such as ornithopods.

It seems to imply that carcharodontosaurids didn't have any special adaptations for caudofemoralis mass.

[/quote]I cannot see any such suggestion in the text, just that that of Carnotaurus is particularly large, unsurprising considering it is regarded as one of the fastest theropods, and much smaller than these giant carcharodontosaurs.

There is no comparison with Tyrannosaurus here. Besides, Carnotaurus would have easily escaped any 10m+ theropod, including T. rex.

[wiffle]

No, we should take the mean estimate, as I wrote. That estimate may be underestimated, or maybe not, if so, that also applies to Giganotosaurus.

The study does not provide a range for Giganotosaurus' bite, to my knowledge.

I have not read the Meers study, but I did not scale up pound for pound, I of course did it properly, adjusting for the squared growth of muscular strenght.

While weight will increase with the 3rd power, strenght will just grow with the 2nd. In other words, if you assume an animal grows as much stronger as it grows heavier, you'll produce tremendous overestimates. I only took the skull lenghts (1.6/0.79) and took the square of that, which, again, will yield a conservative estimate adjusting for this.

This still doesn't account for differences in skull morphology, gape, and muscle attachment.

How would Tyrannosaurus' bite force compare if we scaled it up in similar fasion? According to Thomas Holtz, Daspletosaurus's bite force was over Giganotosaurus' estimate, and yet is more lightly built than T. rex's.

dml.cmnh.org/2007Dec/msg00324.html

I guess that greatly overestimated figure you mention perhaps simply based on some tremendously powerful bite in the extant world, disregarding not the square cube law but rather the functional morphology of each animal's jaw.

Indeed, Meers (2002) estimated an astounding 235,123 N bite force for T. Rex by extrapolating the regression line of the combined reptilian and mammalian predator sample to the estimated body mass of a large tyrannosaurid.

Apparently what was wrong with it was this:

Meers (2002) on the other hand may have overestimated maximum bite force. This is mostly because his slope on the regression equation is closer to 1, or proportional increase of bite force with increasing body mass. So the bigger the animal the stronger the bite. However, my own studies suggest that this slope may actually be significantly lower than 1, so in other words, the bigger the animal, the progressively weaker the bite gets relative to its increase in body mass.

Well, you can try it. It may be a bit of a difference, but it's not at all significant. Komodo dragons and crocodiles can both launch precise and quick strikes at their prey, without having a large field of stereoscopic vision.

I can't try it because I don't have only one eye.

They may be able to "launch precise and quick strikes at their prey" but that is not to say their accuracy would not be improved with greater depth perception.

Certainly not. I'm just saying you are overestimating how strong Tyrannosaurus' neck really was.
We can again use the komodo dragon as an analogy, it's bite is largely, if not mainly powered by a postcranial pulling motion. It's neck is significantly thinner relative to it's size than that of big cats, which don't really use their necks for much at all.

So do you think a komodo dragon's neck would thus be weakened if it were thicker?

Here's a diagram of what the neck muscles might look like:

A longer and more flexible neck seems to be crucial for being effictively incorporated in the bite, just loike sufficient power. T. rex neck is thick to bear a heavy cranium with lots of adductor muscle. It's certainly not a slow striker, but very likely not as quick as a lighter-skulled theropod. I also want to remind you most of these Lighter-skulled theropods also seem to have considerable attachments and moment arms (especially Allosauridae, but also Ceratosauridae, Carcharodontosauridae, Sinraptoridae etc.), they are not necessarily weaker at all.

Considering this:

"For instance, in a split second, a T. rex could toss its head at a 45 degree angle and throw a 50kg person five metres in the air. And that's with conservative estimates of the creature's muscle force, says Snively."

It seems like Tyrannosaurus could execute an action requiring neck strength fairly quickly.

Allosaurus' neck muscles are really designed more for ventroflexion. Such an action would probably be more useful as a feeding technique, although it could be employed in a fight to hatchet and rip out flesh.

Based on what are you saying this? Here we enter the field of speculation.

Crocodilian bites don't usually kill without a death roll or drowning. Tyrannosaurus' bite, on the other hand, has been seen to cause large puncture wounds in bone even with feeding bites.

The point is, that you are saying just because it has a higher bite force it has a better bite, frankly that's not true, I just demonstrated. We have no basis for assuming that.

I can't recall ever saying that. I said that if an animal had a greater bite force, that would not harm it.

No, lots of kinds of damage can immediately incapacitate an animal. Eg. sometimes it's enough to cut a tendon in one of the legs, and an animal will be helpless. A bite to the neck would cause devastating damage to the cervical musculature, which is crucial for placing bites-without it, an animal cannot strike back.

Of course doing something like cutting off someone's leg will prevent them from using that leg, but only a CNS injury will disable the entire body from that point back.
Have you ever heard of Clint Malarchuk? He was still able to walk a couple of seconds after he lost a massive quantity of blood from getting his jugular slashed.
Stan is an excellent example of how durable Tyrannosaurus is-there's a hole right through the back of its skull.

But they are probably not sharp enough to cut through something by just touching it, such a bite would just cause the arteria and venes to be shifted. Only a powerful ripping motion would cause significant soft-tissue damage.

Giganotosaurus' teeth are probably not sharp enough for that either. They may be adapted for slicing but they are not razors. Given that pressure, I would also think that most large blood vessels in the tooth's path would be directly crushed and punctured.

Furthermore, to miss an artery or vein, it would have to fit right between these teeth:

Without a sharp edge, the likelyhood of severing something is not that great. It is for that reason you usually don't see victims of big cat or crocodile attacks bleeding to death in a reasonable amount of time. Most soft tissues are compressable without sustaining much damage, pressure alone doesn't rupture them that easily.

Tyrannosaurus teeth are still superior in the slicing department than big cats and crocodiles. They are also larger and longer than the latter, and more tightly packed and in much greater numbers than the latter. Both types of extant animals can crack bone with some effort, but it's usually not as easy as simply biting.

Neural arches are very thin bone and that's a massive saw. But as I said, it's chances of doing major damage on them are slim, just like T. rex' chances of severing the major structures of the throat or the musculature.

They seem to offer decent enough protection from what I can see:

Presuming the teeth even go that deep.

That's an only very slightly convex area, so I doubt that, especially that it could catch enough tissue in it's jaws and bite down hard enough to do notable damage. at best it would rip off a bit of skin and fascia.

Tyrannosaurus' gape is about 4 ft, so I think that should be enough.

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

It won't be an initial attack unless in very rare cases, it will rather be a securing of the prey animal after it has been apprehended with the jaws, ie. it could hook into something after biting it in case the first bite doesn't kill immediately (such as with a bite to the thoracic/abdominal/pelvic/caudal regions).

A body slam would probably get Tyrannosaurus free from such a grip. These are theropods in the multi-ton range we're talking about.

Sorry to say that, but those scales from Wikimedia are terribly inaccurate, the depictions are horrible, they aren't scaled correctly at all (because that happens to be very difficult), and even if they were, wouldn't objectively reflect their sizes.

It doesn't matter what scale you use; every one shows that Tyrannosaurus wouldn't have to change its posture significantly. At most, it has to elevate its head and neck a little.

It's accelleration wouldn't be quick enough to effectively charge at all

Because?

well, I highly doubt that's the case.

Why?

Because we only have two specimens, one of which is just a dentary and the other one not even properly described. Would you really expect we'd have found bite marks on these two if the species showed great intraspecific agression?

If they fought as much as Tyrannosaurus, I would think there would be at least some signs of roughhousing. Given that there is no evidence as of yet, I don't see what reason there is to believe Giganotosaurus fought among itself just as much.

Neither would it help it. It would make it's gape slightly smaller, it's head slightly heavier and cause it's teeth to break a slightly more often, but neither is going to have notable effect, neither will a bit over 200kg of additional bite force have.

Forget the muscle attachment, let's just say Giganotosaurus' bite force is higher than previously thought. You're trying to make a case for that yourself.

Both would easily kill me, it's completely indifferent.

Btw that has to be one big hippo, and one small elephant in your scenario.

What if you were an elephant getting sat on by either a hippo or another elephant?

2950 pounds is a female hippo, and not a very large one at that. 10,000 pounds is a small/medium weight elephant.

Sue at it's liberal end is thought to be 9t. 7t is still a completely reasonable estimate for the lower one.

It doesn't make much of a difference. The point is that the Meers study calculated for a Tyrannosaurus smaller than average, whereas Sue is larger than average.

save for being kicked, crushed, toppled and/or trampled by an angry collossus rushing forward.

Then don't attack it from the front.

All theropod necks are S-shaped.

Some more so than others. Refer to the previous scale of both.

The computed average strengths of Allosaurus fragilis nasals are
higher than those of the albertosaurine tyrannosaurids when
plotted against nasal length

The nasals are not stronger per se, but you are right in that their skull roofs are less kinetic and probably stronger structures.

Our results for the geometric contribu?
tions to nasal strength artificially exaggerate the strengths of
the Allosaurus fragilis nasals, and diminish those of Gorgo?
saurus libratus and Albertosaurus sarcophagus. The com?
puted average strengths of Allosaurus fragilis nasals are
higher than those of the albertosaurine tyrannosaurids when
plotted against nasal length (Fig. 8). However, averages for
the albertosaurine tyrannosaurid nasals are reduced by
strength properties of their flat caudal projection, where ar?
ticulating bones would augment the nasal strengths. The an?
terior, vaulted portions of the albertosaurine nasals, where
they would receive the brunt of forces from the maxillae,
have higher strengths than the A. fragilis nasals (Fig. 9).
Also, pneumaticity of theA. fragilis nasals (Fig. 5) would re?
duce their strengths somewhat.

This only refers to albertosaurinae, which have less robust skulls that are not as well-suited for producing higher bite forces.

I cannot see any such suggestion in the text, just that that of Carnotaurus is particularly large, unsurprising considering it is regarded as one of the fastest theropods, and much smaller than these giant carcharodontosaurs.

The paper claims that Carnotaurus may have evolved to hunt smaller prey so as to avoid competition. Seems like simply being smaller alone wouldn't have allowed it to fulfill this niche quite so well. It makes no note of carcharodontosaurids having any such bodily features that would allow them to catch these animals. Given that carcharodontosaurids generally hunt large, sluggish prey, there is no real need for outstanding mobility.

Edit: These are quotes from Spinodontosaurus regarding agility:

given Tyrannosaurus' slightly lower, wider and more compact build (as in, at weight parity, it would not be as long as Giganotosaurus) in addition to it's arctometatarsus, it would have been the more agile animal here.

At equal weights, Giganotosaurus would be longer and would thus suffer from greater rotational inertia.
Think of what would be easier; turning whilst carrying a 10kg horizontal plank, or whilst wearing a 10kg body vest?

[Supercommunist]

If they fought as much as Tyrannosaurus, I would think there would be at least some signs of roughhousing. Given that there is no evidence as of yet, I don't see what reason there is to believe Giganotosaurus fought among itself just as much.

Agreed. Even juvenile tyrannosaurs are known to engage in serious fights.

In a new scientific paper, researchers from Northern Illinois University and the Burpee Museum of Natural History in Rockford report that adolescent tyrannosaurs got into some serious scraps with their peers.
The evidence can be found on Jane, the museum's prized juvenile Tyrannosaurus rex, discovered in 2001 in Montana.
Jane's fossils show that she sustained a serious bite that punctured through the bone of the dinosaur's left upper jaw and snout in four places, the researchers report. The injury wasn't life threatening and eventually healed over, according to the scientists. The bite did leave scars, however.
"Jane has what we call a boxer's nose," says Joe Peterson, an NIU Ph.D. candidate in geology and lead author of the study published in the November issue of the journal Palaios. "Her snout bends slightly to the left. It was probably broken and healed back crooked."
The researchers determined that another juvenile tyrannosaur was responsible for the injury.
"Only a few animals could have inflicted the wound," Peterson says, noting that the bite marks were oblong-shaped. A crocodile or an adult T. rex would have left different types of bite marks.
"When we looked at the jaw and teeth of Jane, we realized her bite would have produced a very close match to the injuries on her own face," Peterson says. "That leads us to believe she was attacked by a member of the same species that was about the same age. Because the wound had healed, we think this happened when Jane was possibly a few years younger."
Peterson and Mike Henderson, curator of earth sciences at the Burpee Museum and also a Ph.D. candidate in geology at NIU, were members of the museum group that unearthed the pristine dinosaur skeleton. NIU Presidential Research Professor Reed Scherer, also among the new study's authors, worked as an adviser on the find.
"What's unique about this work is we learn something very, very specific about juvenile dinosaur behavior," Scherer says. "This was an animal about the same size that attacked Jane. Whether it was a sibling or from a rival group, we don't know, but it's fun to speculate."
The sex of Jane, who was named after a museum donor, is unknown. The dinosaur was young when it died, but the Burpee Museum's display leaves no doubt that it was still a creature to be reckoned with. Twenty-two feet long and 7-1/2 feet high at the hip, the young dinosaur tipped the scales at about 1,500 pounds. And it was built to kill, with 71 serrated teeth.
Still, Jane was vastly smaller than an adult T. rex. After much study and consultation with leading U.S. dinosaur experts, Henderson, who led the Montana expeditions, announced in 2006 that Jane was a late juvenile T. rex, about 11 or 12 years old.
"The study of the bite marks on Jane's face demonstrates that even at a young age this dinosaur was engaging in some pretty serious combat," Peterson says. He likened the animal to an adolescent that hadn't quite reached what would have been a huge growth spurt.
The puncture wounds were first noticed several years after the dinosaur was discovered.
"When Jane's skull was found, the bones were disarticulated, or in pieces," Peterson says. "I was examining the casts of the skull bones. I saw that when the left maxilla (upper jawbone) was pieced together, it had more holes in it than the right side. And there was a pattern to the gaps in the side of the face.
"The surface of the face and edges around the puncture marks were smooth, indicating that there hadn't been a fresh break there and the wounds must have healed over while the animal was alive," he adds.
Dr. Christopher Vittore, a Burpee Museum board member and radiologist at Rockford Memorial Hospital, who also contributed to the study in Palaios, took CT scans of the fossils and confirmed Peterson's hypothesis.
"CT scans demonstrated that the holes are most consistent with traumatic puncture injuries that had significant time for healing," Vittore says.
"Complete bone healing requires time for bone remodeling, and CT images show the internal structure of the bone adjacent to the puncture lesions," Vittore adds. "The internal character of the bone showed the injuries occurred significantly earlier in the animal's life, and there was time for healing. It also confirmed that there were no other abnormalities in the bone adjacent to the lesions."
Because the dinosaur had not reached maturity, the researchers concluded that the combat was not likely over sexual conflict or competition but might have been a learning behavior for young dinosaurs prompted by a show of dominance or territorial dispute.
Peterson says other adolescent animals, particularly juvenile crocodiles, exhibit such fighting behavior.
"It's common to find similar puncture marks on young crocodiles," he says. "We can look at the behavior of these modern living ancestors of dinosaurs and get a good idea of what was going on here."

www.sciencedaily.com/releases/2009/11/091102121454.htm

[Grey]

Sept 19, 2013 9:24:23 GMT 5 wiffle said:

It's a trivial matter, really. You may as well be arguing about which boxer is a centimeter taller than the other. In a giant theropod matchup, height does carry quite some significance but weight is nearly meaningless. It's fine for a general paleontological discussion but more or less useless in a fight.

The recent 6 ton bite force estimates seem to be rather on the conservative side. I suspect this may be because 1) the study might not have accounted for the skull structure and application of the bite's strength and 2) the test specimen was Stan, who, while of a healthy size, is not really the biggest one out there.

The study predicting 3.5-5.7 tonnes of bite for Tyrannosaurus was only using Stan ? I may have missed that.

[Grey]

Sept 23, 2013 8:29:39 GMT 5 Supercommunist said:

If they fought as much as Tyrannosaurus, I would think there would be at least some signs of roughhousing. Given that there is no evidence as of yet, I don't see what reason there is to believe Giganotosaurus fought among itself just as much.

Agreed. Even juvenile tyrannosaurs are known to engage in serious fights.

In a new scientific paper, researchers from Northern Illinois University and the Burpee Museum of Natural History in Rockford report that adolescent tyrannosaurs got into some serious scraps with their peers.
The evidence can be found on Jane, the museum's prized juvenile Tyrannosaurus rex, discovered in 2001 in Montana.
Jane's fossils show that she sustained a serious bite that punctured through the bone of the dinosaur's left upper jaw and snout in four places, the researchers report. The injury wasn't life threatening and eventually healed over, according to the scientists. The bite did leave scars, however.
"Jane has what we call a boxer's nose," says Joe Peterson, an NIU Ph.D. candidate in geology and lead author of the study published in the November issue of the journal Palaios. "Her snout bends slightly to the left. It was probably broken and healed back crooked."
The researchers determined that another juvenile tyrannosaur was responsible for the injury.
"Only a few animals could have inflicted the wound," Peterson says, noting that the bite marks were oblong-shaped. A crocodile or an adult T. rex would have left different types of bite marks.
"When we looked at the jaw and teeth of Jane, we realized her bite would have produced a very close match to the injuries on her own face," Peterson says. "That leads us to believe she was attacked by a member of the same species that was about the same age. Because the wound had healed, we think this happened when Jane was possibly a few years younger."
Peterson and Mike Henderson, curator of earth sciences at the Burpee Museum and also a Ph.D. candidate in geology at NIU, were members of the museum group that unearthed the pristine dinosaur skeleton. NIU Presidential Research Professor Reed Scherer, also among the new study's authors, worked as an adviser on the find.
"What's unique about this work is we learn something very, very specific about juvenile dinosaur behavior," Scherer says. "This was an animal about the same size that attacked Jane. Whether it was a sibling or from a rival group, we don't know, but it's fun to speculate."
The sex of Jane, who was named after a museum donor, is unknown. The dinosaur was young when it died, but the Burpee Museum's display leaves no doubt that it was still a creature to be reckoned with. Twenty-two feet long and 7-1/2 feet high at the hip, the young dinosaur tipped the scales at about 1,500 pounds. And it was built to kill, with 71 serrated teeth.
Still, Jane was vastly smaller than an adult T. rex. After much study and consultation with leading U.S. dinosaur experts, Henderson, who led the Montana expeditions, announced in 2006 that Jane was a late juvenile T. rex, about 11 or 12 years old.
"The study of the bite marks on Jane's face demonstrates that even at a young age this dinosaur was engaging in some pretty serious combat," Peterson says. He likened the animal to an adolescent that hadn't quite reached what would have been a huge growth spurt.
The puncture wounds were first noticed several years after the dinosaur was discovered.
"When Jane's skull was found, the bones were disarticulated, or in pieces," Peterson says. "I was examining the casts of the skull bones. I saw that when the left maxilla (upper jawbone) was pieced together, it had more holes in it than the right side. And there was a pattern to the gaps in the side of the face.
"The surface of the face and edges around the puncture marks were smooth, indicating that there hadn't been a fresh break there and the wounds must have healed over while the animal was alive," he adds.
Dr. Christopher Vittore, a Burpee Museum board member and radiologist at Rockford Memorial Hospital, who also contributed to the study in Palaios, took CT scans of the fossils and confirmed Peterson's hypothesis.
"CT scans demonstrated that the holes are most consistent with traumatic puncture injuries that had significant time for healing," Vittore says.
"Complete bone healing requires time for bone remodeling, and CT images show the internal structure of the bone adjacent to the puncture lesions," Vittore adds. "The internal character of the bone showed the injuries occurred significantly earlier in the animal's life, and there was time for healing. It also confirmed that there were no other abnormalities in the bone adjacent to the lesions."
Because the dinosaur had not reached maturity, the researchers concluded that the combat was not likely over sexual conflict or competition but might have been a learning behavior for young dinosaurs prompted by a show of dominance or territorial dispute.
Peterson says other adolescent animals, particularly juvenile crocodiles, exhibit such fighting behavior.
"It's common to find similar puncture marks on young crocodiles," he says. "We can look at the behavior of these modern living ancestors of dinosaurs and get a good idea of what was going on here."

www.sciencedaily.com/releases/2009/11/091102121454.htm

These abundant evidences of fighting among T. rex lead to think they may have been among the most agressive creatures of their size range in the history, even among giants theropods standards. Even if others theropods species are less numerous in remains and could have been just as agressive (abelisaurids), I don't think that the very numerous Allosaurus skeletons show proportionnally just as numerous wounds from intraspecific conflicts as in Tyrannosaurus skeletons.

[wiffle]

The study predicting 3.5-5.7 tonnes of bite for Tyrannosaurus was only using Stan ? I may have missed that.

According to this, yes.
blog.everythingdinosaur.co.uk/blog/_archives/2012/02/29/new-research-into-tyrannosaurus-rex-bite-force.html
Also, newtons to short tons doesn't really work by a 10000:1 conversion-it's actually about 8896:1.

[creature386]

Sept 23, 2013 6:37:28 GMT 5 wiffle said:

Considering this:

"For instance, in a split second, a T. rex could toss its head at a 45 degree angle and throw a 50kg person five metres in the air. And that's with conservative estimates of the creature's muscle force, says Snively."

It seems like Tyrannosaurus could execute an action requiring neck strength fairly quickly.

Remember Snively also said this:

However, until accelerations of the feeding apparatus are assessed for large theropods with larger arms, we cannot conclude that T. rex compensated for reduced forelimbs with rapid strikes, or that it was more adept than large-armed carnosaurs at accelerating its head for attack.

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

So it is still possible that carnosaurs win there, as no one compared them. Therefore I would call theropod's "light skull" argument still valid.

Sept 23, 2013 6:37:28 GMT 5 wiffle said:

Tyrannosaurus' gape is about 4 ft, so I think that should be enough.

Where is that number from? I couldn't find a source about Tyrannosaurus gape. A link would be appreciated.

[theropod]

The study does not provide a range for Giganotosaurus' bite, to my knowledge.

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.

This still doesn't account for differences in skull morphology, gape, and muscle attachment.

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

How would Tyrannosaurus' bite force compare if we scaled it up in similar fasion? According to Thomas Holtz, Daspletosaurus's bite force was over Giganotosaurus' estimate, and yet is more lightly built than T. rex's.

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.

They may be able to "launch precise and quick strikes at their prey" but that is not to say their accuracy would not be improved with greater depth perception.

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.
I'm not saying this cannot be advantageous, but the observable results won't necessarily be very notable. It may rather constitute a long-term evolutionary advantage.

So do you think a komodo dragon's neck would thus be weakened if it were thicker?

No, not in the slightest, it would of course get stronger as regards it's muscular power. It's important to find the right balance between sheer muscle volume, neck lenght and flexibility to be a good striker tough.

Allosaurs tend to have flexible necks, and, while they only have relatively small moment arms and attachments for lateroflexion (like T. rex for ventroflexion), wouldn't have needed to excert comparable amounts of force to accellerate their skulls, so they may win in this category. Several muscles serving for ventro/dorsiflexion insert more or less far dorsally, and in combination must have also moved the skull very quickly.

This all gets much more difficult with a thick, short neck and heavy skull, that always requires significant leverage and force to be moved, contrary to a skull that can be moved with much less efford and with smaller muscle contractions. It can therefore be expected to be slower to strike, albeit the difference perhaps could be slim.

Considering this:

"For instance, in a split second, a T. rex could toss its head at a 45 degree angle and throw a 50kg person five metres in the air. And that's with conservative estimates of the creature's muscle force, says Snively."

It seems like Tyrannosaurus could execute an action requiring neck strength fairly quickly.

Sure.

Allosaurus' neck muscles are really designed more for ventroflexion. Such an action would probably be more useful as a feeding technique, although it could be employed in a fight to hatchet and rip out flesh.

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.
This does not hold true for Carcharodontosaurs to the same degree, which are less specialized in this area, however there is nothing suggesting their neck musculature was weak.

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.

Crocodilian bites don't usually kill without a death roll or drowning. Tyrannosaurus' bite, on the other hand, has been seen to cause large puncture wounds in bone even with feeding bites.

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.

I can't recall ever saying that. I said that if an animal had a greater bite force, that would not harm it.

That depends on the animals, an animal with a high bite force also needs it, one without it doesn't have a need for it, and having it would actually pose problems in the latter case.

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.

Of course doing something like cutting off someone's leg will prevent them from using that leg, but only a CNS injury will disable the entire body from that point back.

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.

Have you ever heard of Clint Malarchuk? He was still able to walk a couple of seconds after he lost a massive quantity of blood from getting his jugular slashed.

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

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

Stan is an excellent example of how durable Tyrannosaurus is-there's a hole right through the back of its skull.

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.

Giganotosaurus' teeth are probably not sharp enough for that either. They may be adapted for slicing but they are not razors.

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.
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.

Given that pressure, I would also think that most large blood vessels in the tooth's path would be directly crushed and punctured.

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.
I know T. rex has serrated teeth, but they are comparatively blunt tools nevertheless ("like a dull, smooth blade", which is quite a difference compared to your average steakknife tooth).

Furthermore, to miss an artery or vein, it would have to fit right between these teeth:

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.

This all simply points out to their bites having comparable potency, a crushing bite is not omnipotent and can do everythign with the same efficiency.

They seem to offer decent enough protection from what I can see:

Presuming the teeth even go that deep.

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.
Yes, the medulla is protected well enough to be relatively save (never totally save, considering how big cats often merely puncture through the gaps between the vertebrae which are also present here), just like the major blood vessels, muscles and tendons are from a T. rex bite, as explained above.

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

Giganotosaurus by comparison would have a gape closer to 8ft.

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.

A body slam would probably get Tyrannosaurus free from such a grip. These are theropods in the multi-ton range we're talking about.

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.

It doesn't matter what scale you use; every one shows that Tyrannosaurus wouldn't have to change its posture significantly. At most, it has to elevate its head and neck a little.

Well, since Giganotosaurus is definitely the taller animal (tough perhaps slightly), it would have an even easier time. Whatever, I highly doubt there are many situations a Tyrannosaurus would effectively attack the dorsal side of something that tall, after all, that something isn't standing still and letting itself get eaten.

Because?

Because it's a 7t Theropod, it isn't going to charge at an opponent at it's top speed in a fighting situation. Both will never reach their maximum speeds unless they take a decent amount of time to accellerate.

well, I highly doubt that's the case.

Why?

Because nothing gave me any reason to suspect Tyrannosaurus's bite was superior.
That's like saying the bite of some mid-sized dog would totally own even the biggest komodo dragon-a suggestion that would be entirely based on bite force, regardless of how potent their bites are (and of course a komodo dragon bite is in no way inferior to a dog's).

If they fought as much as Tyrannosaurus, I would think there would be at least some signs of roughhousing. Given that there is no evidence as of yet, I don't see what reason there is to believe Giganotosaurus fought among itself just as much.

Are you suggesting most, if not all Tyrannosaurus specimens show injuries related to intraspecific fights? That would have to be the case for us to be supposed to find concrete evidence for the same behaviour in Giganotosaurus with the few specimens we have...

Besides Stan I'm not aware of many T. rex specimens with bite marks inflicted in vivo on them, there are probably several tough. But all of them? Certainly not even close. We cannot expect to find evidence in form of bite marks even in a tremendously agressive species when it's only known from one partial skeleton and a dentary fragment.

The media overhype T. rex in many regards, what a terribly agressive beast it was is among them (not suggesting it wasn't agressive, but it is no killing machine that fights all the time like the one portrayed in JP). And in the absence of data it should obviously not be assumed that one species was so any less.

Forget the muscle attachment, let's just say Giganotosaurus' bite force is higher than previously thought. You're trying to make a case for that yourself.

No, I'm not, I think it's totally irrelevant actually. Since you are so focused on the point of bite force I merely suggested to you the figure you were assuming may be too low.

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.

What if you were an elephant getting sat on by either a hippo or another elephant?

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.

2950 pounds is a female hippo, and not a very large one at that. 10,000 pounds is a small/medium weight elephant.

Well, it should be a 2-3t hippo and a 6t elephant to be fair.

It doesn't make much of a difference. The point is that the Meers study calculated for a Tyrannosaurus smaller than average, whereas Sue is larger than average.

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?

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

Then don't attack it from the front.

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...

Some more so than others. Refer to the previous scale of both.

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.

The paper claims that Carnotaurus may have evolved to hunt smaller prey so as to avoid competition. Seems like simply being smaller alone wouldn't have allowed it to fulfill this niche quite so well.

I don't see the point this has on Giganotosaurus and T. rex. It's well-known Carnotaurus is a particularly fast and cursorial theropod.

It makes no note of carcharodontosaurids having any such bodily features that would allow them to catch these animals.

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

Considering they were apex predators, why should Carcharodontosaurs have special adaptions to catch small prey, and why does the lack of them mean to you they were less agile than Tyrannosaurs that didn't either?

Given that carcharodontosaurids generally hunt large, sluggish prey, there is no real need for outstanding mobility.

sauropods aren't sluggish, and they would have hunted ornithopods too at times, just like Tyrannosaurs. 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.
The method of speculating on locomotor abilities only based on, likewise hypothetised, mobility of the prey will very likely lead to wrong assumptions.

given Tyrannosaurus' slightly lower, wider and more compact build (as in, at weight parity, it would not be as long as Giganotosaurus) in addition to it's arctometatarsus, it would have been the more agile animal here.

At equal weights, Giganotosaurus would be longer and would thus suffer from greater rotational inertia.
Think of what would be easier; turning whilst carrying a 10kg horizontal plank, or whilst wearing a 10kg body vest?

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.

Also, at weight parity Giganotosaurus also has lots of musculature, evenly distributed over the limbs, which should add to it's stability, albeit not it's running efficiency.
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.

[theropod]

wiffle: He means metric tonnes (1000kg) which translate to 10 000N nearly exactly. Most of us are in Europe.

I can confirm the Specimen used in Bates & Falkingham was BHI 3033, see the paper here:
rsbl.royalsocietypublishing.org/content/early/2012/02/25/rsbl.2012.0056.full.pdf

Again, note Stan's skull is just as big as Sue's, so the difference for the bite force estimates would probably be miniscule. Apart from that, why should we even use sue?