Megalodon vs. Livyatan melvillei

[theropod]

So Grey estimates the Yorktown dentition’s dried UJP at roughly 370 cm, correct? This would be roughly consistent with what I would expect judging by its crown widths and the the 119 cm dUJP of the white shark (KO-009) with the 74.7 cm summed tooth widths here→. How representative that is is one of a number of matters I hope we can find better data on, so let’s leave that aside for now and go with the 370 cm jaw perimeter.

This, as a proxy for megalodon’s jaw size, compares to a skull approximately 3 m long (e.294 cm) for the Livyatan holotype. So the dry upper jaw perimeter of the shark is about a quarter greater than the length of the whale’s skull.

A popular subject here has undoubtedly been to compare the size of their jaw apparata, as well as to discuss the (two) best extant analogues, but what I haven’t seen people do so far is discussing the two in conjunction (but I think we should, if people assume jaw size is important than people should be interested to have an analogue with jaw sizes actually representative of this scenario). Usually it’s been two separate points, A: the claim that the shark has far larger jaws and B: that the comparison between the two is roughly like that between extant Carcharodon and Pseudorca. But let’s look at whether that actually holds up.

Pseudorca: As for example recently proposed by elosha11 and grey, a possible analogue for this scenario is the comparison between Pseudorca and Carcharodon.
How large are Pseudorca skulls? Well, Ness 1967 reports a sample of 33 Pseudorca skulls, with skull lengths ranging from 360-686 mm (i.e. including immature individuals), with a mean of 609 mm, but sadly no TLs, but anyway, it seems reasonable that an adult Pseudorca skull would usually be 60-70 cm long.
I know two records of skull lengths with known body lengths of the same specimens, both adults, one is 462 cm in TL with a skull length (CBL) of 595 cm (Baird et al. 1989), the other is 437 cm in skeletal length (TL would be somewhat greater) and 618 cm in CBL. Based on Mollet et al.’s data (here→), to have the same relative jaw size as the megalodon and Livyatan in question most (50% PI) white sharks would have jaw perimeters around 749 and 778 mm and be around 381 cm (356-407 cm) and 368 cm in TL (345-393 cm) respectively.

Orcinus: The other obvious comparison is that with Carcharodon and Orcinus. For some reason, it’s actually more difficult to find skull length measurements of orcas than of false killer whales, but I did some digging and found a few:
Caldwell et al. report a specimen with a 902 mm skull, but sadly the animal was too decomposed to take external body measurements (but they estimated that about one fourth of the posterior end of the animal was missing, which added to the 15 ft that were preserved would have made it about 6 m long. Obviously, low precision, but a ballpark). The corresponding GWS jaw would have a perimeter of about 1135 mm and belong to a shark around 530 cm long (495-566 cm).
Ness 1967 also reports no TL measurements, but they do have measurements of orca skulls, a sample of 11 ranging from 324 to 1001 mm with a mean of 849 mm. Nothing exact, but presumably, a 1001 mm skull would correspond to a good-sized adult (bull?), as Heyning & Dalheim list 100 cm as maximum skull length ("condylobasal length to 100 cm"). A correspondingly sized GWS jaw (with regard to the 1001 mm orca skull, and the size ratio between meg and Livyatan) would have a perimeter of about 1260 mm and be from an individual around 580 cm long (543-620 cm).
If this skull was from an orca around 7-8 m long, then this size disparity could approach that between the 3-4 m great white and 4.7-5.3 m orca involved in the famous predation account (Pyle et al. 1999).

In other words, the Yorktown meg’s jaws would be about the same size relative to the Livyatan holotype’s skull as those of 3.6-3.8 m great whites when compared to 4.4-4.6 m false killer whales, a 5.3 m great white compared to a 6 m orca, or a 5.8 m great white compared to a large adult orca. So despite the claims of how much bigger the shark’s jaws are, the actual discrepancy in jaw size is more similar to that between great white and orca than great white and fkw, unless we are talking about a great white significantly smaller than the fkw.

I know this isn’t the first time I note that Livyatan would have proportionately far larger jaws than the false killer whale (or else would be far larger than estimated), but here is some much needed quantification. Maybe that should be kept that in mind the next time the comparison between meg and Livyatan to that between GWS and FKW or the jaw size discrepancy comes up.

Not only is there still no record of a great white, or any shark for that matter, actually preying on a Pseudorca, but the size of Livyatan’s killing apparatus compared to that of meg is also not at all comparable to that of a Pseudorca compared to an adult great white. On the contrary, the comparison between their killing apparata is actually similar to that between an orca and great white, and I don’t need to tell anyone who is the prey in that scenario.

––References:

Baird, R.W., Langelier, K.M. and Stacey, P.J. 1989. First records of false killer whales, Pseudorca crassidens, in Canada. Canadian field-naturalist. Ottawa ON 103 (3): 368–371.
Caldwell, D.K., Layne, J.N. and Siebenaler, J.B. 1956. NOTES ON A KILLER WHALE (ORCINUS ORCA) FROM THE NORTHEASTERN GULF OF MEXICO. Quarterly Journal of the Florida Academy of Sciences 19 (4): 189–196.
Heyning, J.E. and Dahlheim, M.E. 1988. Orcinus orca. Mammalian Species (304): 1–9.
Mollet, H.F., Cailliet, G.M., Klimley, A.P., Ebert, D.A., Testi, A.D. and Compagno, L.J. 1996. A review of length validation methods and protocols to measure large white sharks. In: Klimley, A. Peter and Ainley, D.G. (eds.), Great White Sharks: The Biology of Carcharodon Carcharias, 91–108. Academic Press, San Diego.
Ness, A.R. 1967. A measure of asymmetry of the skulls of odontocete whales. Journal of Zoology 153 (2): 209–221.
Pardo, M.A., Jiménez-Pinedo, C. and Palacios, D.M. 2009. The false killer whale (Pseudorca crassidens) in the southwestern Caribbean: first stranding record in Colombian waters. Latin American Journal of Aquatic Mammals 7 (1–2): 63–67.
Pyle, P., Schramm, M.J., Keiper, C. and Anderson, S.D. 1999. Predation on a white shark (Carcharodon carcharias) by a killer whale (Orcinus orca) and a possible case of competitive displacement. Marine Mammal Science 15 (2): 563–568.

[Life]

Oct 9, 2019 1:59:24 GMT 5 theropod said:

So Grey estimates the Yorktown dentition’s dried UJP at roughly 370 cm, correct? This would be roughly consistent with what I would expect judging by its crown widths and the the 119 cm dUJP of the white shark (KO-009) with the 74.7 cm summed tooth widths here→. How representative that is is one of a number of matters I hope we can find better data on, so let’s leave that aside for now and go with the 370 cm jaw perimeter.

This, as a proxy for megalodon’s jaw size, compares to a skull approximately 3 m long (e.294 cm) for the Livyatan holotype. So the dry upper jaw perimeter of the shark is about a quarter greater than the length of the whale’s skull.

A popular subject here has undoubtedly been to compare the size of their jaw apparata, as well as to discuss the (two) best extant analogues, but what I haven’t seen people do so far is discussing the two in conjunction (but I think we should, if people assume jaw size is important than people should be interested to have an analogue with jaw sizes actually representative of this scenario). Usually it’s been two separate points, A: the claim that the shark has far larger jaws and B: that the comparison between the two is roughly like that between extant Carcharodon and Pseudorca. But let’s look at whether that actually holds up.

Pseudorca: As for example recently proposed by elosha11 and grey, a possible analogue for this scenario is the comparison between Pseudorca and Carcharodon.
How large are Pseudorca skulls? Well, Ness 1967 reports a sample of 33 Pseudorca skulls, with skull lengths ranging from 360-686 mm (i.e. including immature individuals), with a mean of 609 mm, but sadly no TLs, but anyway, it seems reasonable that an adult Pseudorca skull would usually be 60-70 cm long.
I know two records of skull lengths with known body lengths of the same specimens, both adults, one is 462 cm in TL with a skull length (CBL) of 595 cm (Baird et al. 1989), the other is 437 cm in skeletal length (TL would be somewhat greater) and 618 cm in CBL. Based on Mollet et al.’s data (here→), to have the same relative jaw size as the megalodon and Livyatan in question most (50% PI) white sharks would have jaw perimeters around 749 and 778 mm and be around 381 cm (356-407 cm) and 368 cm in TL (345-393 cm) respectively.

Orcinus: The other obvious comparison is that with Carcharodon and Orcinus. For some reason, it’s actually more difficult to find skull length measurements of orcas than of false killer whales, but I did some digging and found a few:
Caldwell et al. report a specimen with a 902 mm skull, but sadly the animal was too decomposed to take external body measurements (but they estimated that about one fourth of the posterior end of the animal was missing, which added to the 15 ft that were preserved would have made it about 6 m long. Obviously, low precision, but a ballpark). The corresponding GWS jaw would have a perimeter of about 1135 mm and belong to a shark around 530 cm long (495-566 cm).
Ness 1967 also reports no TL measurements, but they do have measurements of orca skulls, a sample of 11 ranging from 324 to 1001 mm with a mean of 849 mm. Nothing exact, but presumably, a 1001 mm skull would correspond to a good-sized adult (bull?), as Heyning & Dalheim list 100 cm as maximum skull length ("condylobasal length to 100 cm"). A correspondingly sized GWS jaw (with regard to the 1001 mm orca skull, and the size ratio between meg and Livyatan) would have a perimeter of about 1260 mm and be from an individual around 580 cm long (543-620 cm).
If this skull was from an orca around 7-8 m long, then this size disparity could approach that between the 3-4 m great white and 4.7-5.3 m orca involved in the famous predation account (Pyle et al. 1999).

In other words, the Yorktown meg’s jaws would be about the same size relative to the Livyatan holotype’s skull as those of 3.6-3.8 m great whites when compared to 4.4-4.6 m false killer whales, a 5.3 m great white compared to a 6 m orca, or a 5.8 m great white compared to a large adult orca. So despite the claims of how much bigger the shark’s jaws are, the actual discrepancy in jaw size is more similar to that between great white and orca than great white and fkw, unless we are talking about a great white significantly smaller than the fkw.

I know this isn’t the first time I note that Livyatan would have proportionately far larger jaws than the false killer whale (or else would be far larger than estimated), but here is some much needed quantification. Maybe that should be kept that in mind the next time the comparison between meg and Livyatan to that between GWS and FKW or the jaw size discrepancy comes up.

Not only is there still no record of a great white, or any shark for that matter, actually preying on a Pseudorca, but the size of Livyatan’s killing apparatus compared to that of meg is also not at all comparable to that of a Pseudorca compared to an adult great white. On the contrary, the comparison between their killing apparata is actually similar to that between an orca and great white, and I don’t need to tell anyone who is the prey in that scenario.

––References:

Baird, R.W., Langelier, K.M. and Stacey, P.J. 1989. First records of false killer whales, Pseudorca crassidens, in Canada. Canadian field-naturalist. Ottawa ON 103 (3): 368–371.
Caldwell, D.K., Layne, J.N. and Siebenaler, J.B. 1956. NOTES ON A KILLER WHALE (ORCINUS ORCA) FROM THE NORTHEASTERN GULF OF MEXICO. Quarterly Journal of the Florida Academy of Sciences 19 (4): 189–196.
Heyning, J.E. and Dahlheim, M.E. 1988. Orcinus orca. Mammalian Species (304): 1–9.
Mollet, H.F., Cailliet, G.M., Klimley, A.P., Ebert, D.A., Testi, A.D. and Compagno, L.J. 1996. A review of length validation methods and protocols to measure large white sharks. In: Klimley, A. Peter and Ainley, D.G. (eds.), Great White Sharks: The Biology of Carcharodon Carcharias, 91–108. Academic Press, San Diego.
Ness, A.R. 1967. A measure of asymmetry of the skulls of odontocete whales. Journal of Zoology 153 (2): 209–221.
Pardo, M.A., Jiménez-Pinedo, C. and Palacios, D.M. 2009. The false killer whale (Pseudorca crassidens) in the southwestern Caribbean: first stranding record in Colombian waters. Latin American Journal of Aquatic Mammals 7 (1–2): 63–67.
Pyle, P., Schramm, M.J., Keiper, C. and Anderson, S.D. 1999. Predation on a white shark (Carcharodon carcharias) by a killer whale (Orcinus orca) and a possible case of competitive displacement. Marine Mammal Science 15 (2): 563–568.

Following comparison will provide a fairly good idea.



Scaled to Livyatan



Megalodon could literally crush the rib cage of Livyatan if it wanted to. And this isn't far-fetched assumption.

Megalodon bitten sperm whale bones are ending up in the hands of private collectors fortunately or unfortunately! Let us not forget this. Paleontologists might have to stick to collections in Museums for their works but people do not have to.

Great white shark does not represent Megalodon in behavior as well as implied raw power. Being the closest living analogue does not translate into anything concrete in regards to closeness to Megalodon in real life.

[theropod]

^I don’t think you are really addressing the point I was making. It is that despite the various people here focusing on how much bigger megalodon’s jaws seem to be than Livyatan’s, the jaws of a large megalodon aren’t bigger compared to those of Livyatan than those of a large great white shark are compared to an orca. So if jaw size is such a major factor, then that is weird, as is the commonly proposed analogy of GWS vs FKW, which doesn’t properly reflect their relative jaw sizes at all.


Whether or not megalodon could "crush the ribcage" of Livyatan, or whether there are any fossils in private hands that provide evidence of this (not that I have ever heard or seen anything that suggests this) is a totally different topic.

[Life]

Oct 10, 2019 0:01:21 GMT 5 theropod said:

^I don’t think you are really addressing the point I was making. It is that despite the various people here focusing on how much bigger megalodon’s jaws seem to be than Livyatan’s, the jaws of a large megalodon aren’t bigger compared to those of Livyatan than those of a large great white shark are compared to an orca. So if jaw size is such a major factor, then that is weird, as is the commonly proposed analogy of GWS vs FKW, which doesn’t properly reflect their relative jaw sizes at all.


Whether or not megalodon could "crush the ribcage" of Livyatan, or whether there are any fossils in private hands that provide evidence of this (not that I have ever heard or seen anything that suggests this) is a totally different topic.

A rough comparison of fairly good resconstructions of the jaw structure of these two animals, is in the picture I have posted above. I believe that this photo will give you (and others) a rough idea.

My personal view of this matter is in this link: theworldofanimals.proboards.com/post/47526/thread

---

I base my views about what a Megalodon could achieve in a hypothetical confrontation on strictly professional views about the Megalodon's inferred mechanical prowess (Bretton Kent, 1999; Wroe et al., 2008) and attacking strategies (Bretton Kent, 1999; Mike deGruy, 2008).



A large Megalodon could in fact crush the very rib cage of a Livyatan in a potential confrontation. This attacking strategy make sense in order for the Megalodon to minimize potential risks to itself and the assumption that a potentially dangerous subject could be taken out swiftly in this manner.

Why should a Megalodon risk a prolonged confrontation with a large and powerful animal in which probability of suffering injuries might increase manifold as the fight continue to drag on? Being a solitary hunter, it is in the best interest of a Megalodon to end this fight as quickly as possible, and it most likely could.

Now, do you seriously expect to come across a well-preserved rib cage of Livyatan bearing imprints from a Megalodon at any point in time? Nevermind the fact that WE have a largely incomplete holotype and a small number of isolated teeth of Livyatan to consider in our calculus at most?

You are most likely to notice isolated remains - belonging to ancient sperm whales - providing evidence of trophic interactions with Megalodon which usually ended badly for the cetaceans by the looks of it.

Two examples in this thread: theworldofanimals.proboards.com/thread/77/shark-bitten-fossil-bones?page=5

[Grey]

Theropod, nothing really new here and it seems you totally missed the point that time.

Livyatan and meg jaws are so much different that I am not surprised on this relationship.

You don't remember one thing however; when we discuss and compare them, we talk about bite volume.

Based on the size of the chunks of flesh taken out by GWS and the purpoted size of megalodon, and anecdotically, a life-size test in mythbusters supervised by Chuck Ciampaglio) a megalodon bite that size would take between 600 and 900 kg of organic substance into one bite.

Do you expect Livyatan's bite to take that amount of flesh or even larger ?

As for the comparison orca/GWS, do I need to recall the massive size disparity between orcas and GWS that is not present so far between the two extinct critters ?

Orcas jaws, especially the mandible, are much wider at the same skull length than Livyatan.

The relevance of the comparison stops here.

Orcas have several tons and a hunting culture (for some populations) that allow them to prey on GWS.

Livyatan is a totally different case from a totally different era for marine megafauna.

And comparing jaw perimeter with total skull length of cetaceans ? Here I call Physeter macrocephalus... going by this criterion.


The FKW/GWS Livyatan/meg comparison is based on two points :

- the similar size range
- the fact FKW are really big toothed

Which one could take out bigger chunks of flesh is obvious or by your logic the champion is Physeter with his 5 m mandible.



If you want to compare jaws, test some bite volume but I'm pretty confident on the results.

To summarize, your comparison of orca skull vs GWS jaws perimeter with the Neogene titans would work only if Livyatan was a giant orca twice heavier than megalodon. Which is not true AFAWCT.

[theropod]

No Grey , I am not missing a point, because I am the one making it.

I was not claiming that Livyatan would have "taken larger chunks of flesh" than megalodon", or making any claims about bite volume for that matter. I think I have made it clear years ago that I don’t find that comparison very meaningful, as Livyatan’s jaws are simply not built for taking out chunks of flesh in the first place. You can disagree with that, that’s also not the point, the point is that if you talk about the larger bite volume, you should consider that a great white shark would also have a larger bite volume than a bull orca based on the same figures.

Sperm whales are not relevant, firstly they have no functional upper dentition, secondly their jaws are entirely different in shape. On the other hand, the morphological similarity between orcas and Livyatan has been repeatedly noted, there is no point in trying to argue about it. That doesn’t mean they are the exact same shape, but it does mean an orca skull and Livyatan skull scaled to the same length are roughly comparable, unlike either is with a Physeter skull.

And that obviously doesn’t prevent great white sharks from being eaten by orcas, so perhaps the bite volume is not as critical a factor as you make it out to be. Furthermore, once again, I am pointing out that the jaws of Livyatan are way bigger compared to those of megalodon than those of a FKW compared to an adult GWS.

Now Livatan is not an orca. But that doesn’t change the fact that it’s jaws are about the same size compared to those of megalodon as those of an orca when compared to a great white shark.

Life

Here is a better comparison, shark jaw scaled to the jaw perimeter Grey proposes (370 cm * sin(62°), as the jaw in your picture is angled to the horizontal by approximately 62°).

Based on that, I have some problems with the proposition that megalodon could "crush Livyatan’s ribcage".

The Livyatan shown here is the conservative estimate, 14.2 m, with a body based on P. macrocephalus, so it’s not as large or as deep-chested as it would likely be when based on closer relatives, yet it seems clear that the chest of the Livyatan would not fit inside the megalodon jaws to be crushed.

Certainly a bite by the shark would cause a grievous injury, but so would the bite of the whale.

Attachments:

[Grey]

And that obviously doesn’t prevent great white sharks from being eaten by orcas, so perhaps the bite volume is not as a critical factor as you make it out to be.

But it is if the two opponents are closer in overall size.

The point I'm making point is :
- the shark has larger bite volume, so is going to impact a larger area than its foe with the same weapon.

- the shark has a larger oral cavity

Nice comparison once again. No this meg can't crush Livyatan's chest but it certainly can take a huge volume of flesh out of it. One bite is potentially fatal even for Livyatan.

It would be interesting to have a frontal view comparison in addition for Livyatan and a profile for the meg jaws.

Not to forget the dentition on which is not particularly large.

Yes, there were larger Livyatan individuals but we don't know by how much. There is a bias toward meg material of course, but the absence of more Livyatan material is not a reason to exclude any potentially larger or smaller meg to use in comparison.

EDIT : not useless to recall this jaw perimeter is a slight conservative figure due to shrinkage in the original comparison. Small and perhaps unsignificant but still worth to mention.

Btw, how did you measure the UJP on this reconstructed jaw ?

[theropod]

^And did you see me suggesting Livyatan preying on megalodon the way orcas do with great whites anywhere?

- the shark has larger bite volume, so is going to impact a larger area than its foe with the same weapon.

The area a bite actually impacts is proportional to the length of the tooth row, not the space between them. If an animal has two deep cuts metres in length across its body, it matters precious little if the distance between those two cuts is 1 m or 2 m, the blood loss will be about the same either way.

But then again, Livyatan’s teeth are not adapted to cut in the first place.

No this meg can't crush Livyatan's chest but it certainly can take a huge volume of flesh out of it. One bite is potentially fatal even for Livyatan.

And have I ever called that into question? No.
Of course one bite by Livyatan is potentially fatal for megalodon too, if not due to mechanical damage (though surely devastating as well) then due to the immobilizing grip making ram ventilation impossible.

EDIT : not useless to recall this jaw perimeter is a slight conservative figure due to shrinkage in the original comparison. Small and perhaps unsignificant but still worth to mention.

You can repeat the calculations and add 7 cm (2%) for shrinkage if you want, that makes very little difference to the implications. On the other hand, as I’ve previously outlined I think the perimeter estimate is pretty liberal, as the shark seems to have an unusually large perimeter for the size of its teeth, but I’m fine with going with this figure for now if that’s something you can agree to use.

It would be interesting to have a frontal view comparison in addition for Livyatan and a profile for the meg jaws.

No good frontal view pictures of Livyatan’s skull available, too much perspective. That’s why you guys always use random people in the frame for scaling, after all, resulting in comparisons where the two things being compared differ by several metres in terms of how far they are from the camera in the respective shots.

Not to forget the dentition on which is not particularly large.

That is scaled to the jaw perimeter you estimate for the Yorktown dentition.

Actually, while we are at it:

conservative vs conservative: Livyatan holotype with 197 cm BZW and 294 cm CBL based on Physeter (14.2 m standard length), meg with 370 m dUJP based on Mollet et al.’s data (14.9 m TL).

Attachments:

[Grey]

And that obviously doesn’t prevent great white sharks from being eaten by orcas, so perhaps the bite volume is not as a critical factor as you make it out to be.

No ! But it is misleading to note the similar ratio of the jaws without mentioning the sheer mass (and potential hunting techniques) that makes orcas the predator of the GWS.

The area a bite actually impacts is proportional to the length of the tooth row, not the space between them. If an animal has two deep cuts metres in length across its body, it matters precious little if the distance between those two cuts is 1 m or 2 m, the blood loss will be about the same either way.

And the shark is not supposed to head-shake and take out a chunk which will be larger than the one Livyatan will be able to take out ?

I don't expect the exact same blood loss from Livyatan's bite either.

Of course one bite by Livyatan is potentially fatal for megalodon too, if not due to mechanical damage (though surely devastating as well) then due to the immobilizing grip making ram ventilation impossible.

Has this immobilizing grip been observed while performed by an odontocete on a foe the same size it is ?

In terms of mechanical damage, unless of a bite force unexpected even for Livyatan was to be found, I don't see a bite to be that lethal on a megalodon the same size, especially not knowing the punishment large sharks can take.

I don't think the JP is liberal, I think we severely overestimated the size of the toothrow in relation to the jaw perimeter. Because there is nothing indicating the GWS jaws from boneclones come from a shark particularly big mouthed.

Nice comparison but looking at it in terms of size of the biting apparatus, I still give a slight edge to the shark in that case.

[theropod]

No ! But it is misleading to note the similar ratio of the jaws without mentioning the sheer mass (and potential hunting techniques) that makes orcas the predator of the GWS.

Well, I think everyone here knows that orcas are bigger than great whites. It’s certainly no less misleading to note the (maybe…) similar ratio between the body sizes of GWS and FKW without mentioning the very different relative sizes of their jaw apparata. And also, the former isn’t actually an analogy I am proposing for this fight, because I am well aware of the differences, whereas the latter has been proposed as a supposedly good analogue.

And I think you had already responded to the same line in the previous post?

And the shark is not supposed to head-shake and take out a chunk which will be larger than the one Livyatan will be able to take out ?

The Livyatan is not taking out a chunk at all. If it can do that, that’s of secondary concern. It is entirely besides the point to judge Livyatan by its ability to cut out chunks of flesh, that is like judging a crocodile or big cat or T. rex by its ability to cut out chunks of flesh, or a white shark or komodo dragon by its ability to crush bones. It should be obvious that conical, peglike teeth just are not optimized to cut flesh. But there are a variety of other things the whale can do that it is better at than the shark; its head is a giant battering ram, its teeth are an almost inescapable vice, yet you keep focusing on exclusively the part of the picture that the shark is better at.

I don't expect the exact same blood loss from Livyatan's bite either.

No, because it has neither the dentition, nor the jaw mechanics to kill through blood loss. It certainly could tear off a fin, crush a tail, or skull, attack the gills or just plain grip and immobilize the shark.

Has this immobilizing grip been observed while performed by an odontocete on a foe the same size it is ?

Yes, by orcas, on sperm whales. It is how they break up sperm whale defensive formations. A bull orca can reportedly take a living adult sperm whale in its jaws, carry it off, violently shake it around, and "spin it around at the surface".
Read Pitman et al. 2001.

Of course an adult female sperm whale is likely still bigger than a typical bull orca, Livyatan has proportionately much larger jaws, and this shark won’t take several hours to suffocate if it cannot ram-ventilate, unlike a sperm whale. So if anything, Livyatan should be better at this.

No, a sperm whale is not a megatooth shark, but that’s not relevant, this is just about the whale’s capacity to effectively restrain a large, powerful foe with the jaws; the answer to the question you asked, which is "yes". I don’t think a megalodon would be so vastly more powerful than a similar-sized (let alone larger) sperm whale to dismiss this analogy.

I don't think the JP is liberal, I think we severely overestimated the size of the toothrow in relation to the jaw perimeter.

Well, you should maybe discuss that with Kent, he was the one who took the previous measurement I was using, based on which the ratio would be considerably smaller. It is a bit of a strong statement to say we are "severely underestimating" something based on only one single specimen, but well…
I already wrote that I can go with this figure for now if you can agree with it. Otherwise, I’d hardly have spent so much time doing calculations and comparisons based on it, would I?

[Life]

Oct 10, 2019 2:23:57 GMT 5 theropod said:

Life

Here is a better comparison, shark jaw scaled to the jaw perimeter Grey proposes (370 cm * sin(62°), as the jaw in your picture is angled to the horizontal by approximately 62°).
View Attachment

Based on that, I have some problems with the proposition that megalodon could "crush Livyatan’s ribcage".

The Livyatan shown here is the conservative estimate, 14.2 m, with a body based on P. macrocephalus, so it’s not as large or as deep-chested as it would likely be when based on closer relatives, yet it seems clear that the chest of the Livyatan would not fit inside the megalodon jaws to be crushed.

Certainly a bite by the shark would cause a grievous injury, but so would the bite of the whale.

That is absurd comparison, not taking into account the elasticity factor in the opening of the jaw structure in Megalodon [as soon as it connect with the body of the target] and neither it tell us anything about the impact of ramming-tearing-breaching-slicing activities on the chest cavity of Livyatan - you will have a potential answer from a complex study of mechanical forces in which this kind of scenario is simulated.

Recall following revelation:-

"The teeth of great whites have the high bending strength ratios of cutting teeth, high slenderness ratios, implying they are not designed for crushing, and roots that are short when compared with the overall tooth height. This means a great white's teeth have a low mechanical advantage and will likely be ripped out by struggling prey. Such a combination of parameters, says Kent, "is ideal for a shark that hunts with a slash-and-release type of attack that concentrates on the softer portions of the prey". Surveys of the corpses of marine mammals killed by great whites confirm that, when feeding on sea lions, small whales and porpoises, the sharks most frequently attack the delicate abdomens or rear flippers of their victims. Though they often tear off chunks of flesh during an attack, the sharks rarely grapple with large prey, waiting instead for the animal to die of injuries, or carrying animals in their jaws until they bleed to death, before feeding at their leisure.

Megalodon teeth, though superficially similar to those of great whites, have an entirely different set of parameters. Though they share the serrated cutting edge, megalodon teeth are comparatively thicker for their size with much lower slenderness and bending strength ratios. They also have roots that are substantially larger relative to total tooth heights, and so have a greater mechanical advantage.

Kent explains that teeth with these traits not only make good cutting tools, but are also well suited to grasping powerful prey and unlikely to crack when they bite down on bone. The differences between the teeth of great white and megalodon suggest fundamental differences in their diet, attack behaviour, or indeed both. But Kent reasons that as large mammals formed the menu of both sharks, the difference in their teeth must be related to variations in their attack behaviour."

Read more: theworldofanimals.proboards.com/thread/10/megalodon?page=8#ixzz61vTjrBIA

Bretton Kent's argument make perfect sense; Great white shark is 'biologically constrained' in regards to how to kill large whales and dolphins (killer whale variety). Great white shark is far better suited to prey on pinnipeds instead, due to its gracile dentition and everything related.

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This is not going to be a senseless biting contest as to who can bite more as the fight continue to drag on. Megalodon will most likely aim for the chest cavity of Livyatan, ruin it, and kill the target swiftly in this manner. This is how it have attacked and killed whales in real life (I have provided examples), and I can provide more examples.

Wrestling massive animals into submission, is energetically costly and risky attacking behavior for a solitary hunter [as a routine]. Megalodon's killing prowess is of utmost importance in this matter, and it featured an excellent killing apparatus for the needful. Not that Megalodon was lacking in sheer raw power (opposite is true) but it is important to understand how Megalodon could live long and healthy while involved in big-game hunting through the years.

[Grey]

Yes, by orcas, on sperm whales. It is how they break up sperm whale defensive formations. A bull orca can reportedly take a living adult sperm whale in its jaws, carry it off, violently shake it around, and "spin it around at the surface". 
Read Pitman et al. 2001.



Of course an adult female sperm whale is likely still bigger than a typical bull orca, Livyatan has proportionately much larger jaws, as I just explained, and this shark won’t take several hours to suffocate if it cannot ram-ventilate, unlike a sperm whale. So if anything, Livyatan should be better at this.

Good argument, however a cow sperm whale in terms of agression and weaponry is not a macropredatory shark.

As vastly superiors as orcas are to any modern GWS, we know that much smaller sharks are still able to land bite marks (presumably in defense) to them.
So, I would strongly recommand to not too heavily rely on the behaviors and relationship between cow sperm whales and orcas to definite Livyatan as the superior fighter.
As I said multiple times in the past, Livyatan and a similar-size megalodon specimen may be pretty much equal in potency, at least as far as we know.

I simply point out that a bite from the shark may be slightly more debilitating than the bite of Livyatan, unless in a vulnerable region. It is good to remember however than sharks can take a lot of punishments.

Stopping the megalodon movement won't simply stop the fight instantly, it takes a moment and particular conditions (such as being handled by a foe much larger) for the shark to lose control and stop breathing.

A trashing megalodon the same size may not be something easy to handle for Livyatan. But I agree that a successful bite on a fin may be dangerous and the most likely technique to use.

From what we can tell from GWS or makos with deeply damaged gills, the vulnerability of this body part is maybe exaggerated but I agree that a deep wound in those regions would force the shark to retreat.

Which one strikes first is just decisive.

[sam1]

It's amazing how this thread keeps going around in circles..

Every meg supporter still, after all this arguing seems fixated on the biting contest premise.

They keep ignoring the extreme likelihood that
- primary intention of Liyatan would be to ram a shark
- if it came to biting, the primary target would likely be the PECTORAL FIN of the shark.

Here's a simple question to meg supporters - what happens if meg's pectoral fin is bitten off?

[Grey]

Same thing with the cetacean, it can possibly survive with one but will retreat.
Hence who strikes first wins.

Stop with this meg supporter, the fact you're a cetacean fan does not make all the people not agreed with you meg fanboys. I merely recall that everything is not that simple with two opponents similar in size. All the sharks killed in the records by cetaceans were either much smaller than their agressor or outnumbered.

A meg and a Livyatan facing themselves withiut element of surprise would most likely resume to endless circlings, as any attempt is potentially fatal to the other.

[sam1]

Oct 10, 2019 15:28:29 GMT 5 Grey said:

Same thing with the cetacean, it can possibly survive with one but will retreat.
Hence who strikes first wins.

Stop with this meg supporter, the fact you're a cetacean fan does not make all the people not agreed with you meg fanboys. I merely recall that everything is not that simple with two opponents similar in size. All the sharks killed in the records by cetaceans were either much smaller than their agressor or outnumbered.

A meg and a Livyatan facing themselves withiut element of surprise would most likely resume to endless circlings, as any attempt is potentially fatal to the other.

Agreed..that's how it likely would have turned out. 

But my vote goes to the whale not because I'm a cetacean fan, but because I always try to see things objectively.
If the situation called for an all out fight, the whale has an advantage in my eyes.
Coming straight towards each other, Livyatan carries more leverage because his ram is likely far more potent, and because the shark's fin is the perfectly exposed target.
Megalodon can only produce deep sideways gashes in return.