Megalodon vs. Livyatan melvillei

[Grey]

There is a recent paper, Gilbert 2018, where large Lee Creek sperm whales teeth are discussed. They estimate the owners to have been 8-10 m, raptorial and with a fast growth compared to modern odontocetes. They attribute this fast growth to the predatory pressures posed by megalodon, reaching quickly adult size allowing them to become more evasive and mobile.

Accretionary growth banding in the teeth of Lee Creek physeteroids indicates a maximum life span of 25 years, similar to thatof small extant odontocetes. This life span is coupled with maximum body length estimates of 8–10 m, smaller than the modern sperm whale and comparable to killer whales. Although body size estimates based on tooth diameter alone are tenuous for all the reasons discussed above, by any measure these were not small whales. The von Bertalanffy growth function suggests a markedly high rate of attainment of adult body size and associated early onset of sexual maturity. These life history traits may be indicative of an evolutionary response to high predation pressure. These animals coexisted with one of the most accomplished predators known to have existed, Carcharocles megalodon. It is likely that C. megalodon, and potentially other large macroraptorial physeteroids, preyed on them and that this ecological interaction acted as a selective mechanism favoring rapid growth and maturation.

[Infinity Blade]

Those are some valid observations, but I just see a ram at full speed as a more potent and efficient way to gain initiative. The bite is a follow up.
Keep in mind that a 40-50ton body charging at around 30km/h and clashing with another body of similar mass would result in a massive kinetic energy release..and such energy needs to be received with the forehead, not by jaws.
Remember the Brygmophyseter vs Megalodon CGI animated episode? The two brygmophyseters(over sized, I know, but that's besides the point) charged and rammed the megalodon

I think I understand what you’re saying. But I still have to decide if ramming and then biting to gain initiative is really better than just outright biting, having the opponent (at least temporarily) in your grasp, and leaving it with a serious wound even after that grasp is lost (since sharks with slicing teeth are admittedly not really adapted for holding).

Even disregarding this there’s still the question: could the shark still also ram its victims? A few others here seems to think so. I wasn’t so sure before since it wasn’t really built like a battering ram to the extent seen in sperm whales, but it seems that such is not really necessary (some baleen whales will also ram with their heads and are most certainly not the living battering rams sperm whales are).

[theropod]

Ok, so there are a few points I’ve read or briefly addressed on the shark bite mark thread or elsewhere, which I’d like to revisit, or mostly, would appreciate some clarifications regarding the evidence of.

1) The claim that the shark was faster and/or more maneuverable.
1a) I know top speed is largely besides the point, but is there even a RELIABLE speed measurement of a great white shark, for comparative purposes?
1b) Infinity Blade : (migrating over here from the shark bite mark thread) Thanks for the information, wasn’t aware of that. I didn’t do in-depth reading on reliable Blue whale speed records. Still, whether 50 or 30km/h, I find that speed very impressive for animals that large. Based on Williams 2002 (in Ford 2005), this still means blue whales are faster than minke whales, despite being easily 10 times the size. So I think that’s sufficient evidence to suggest that size isn’t really that important in terms of top speed. Maneuverability, obviously, is a completely different story. Just that from this I wouldn’t jump to the conclusion that a 50 ton Livyatan or C. megalodon would be particularly slow.
And then, we have the data in sharks that suggests at least cruising speed is positively correlated with size. That is not directly related to top speed, but it still means large sharks need to be able to move quickly.
Ford, J. K., G. M. Ellis, D. R. Matkin, K. C. Balcomb, D. Briggs, and A. B. Morton. 2005: Killer whale attacks on minke whales: prey capture and antipredator tactics. Marine mammal science 21:603–618.
Jacoby, D. M. P., P. Siriwat, R. Freeman, and C. Carbone. 2015: Is the scaling of swim speed in sharks driven by metabolism? Biology Letters 11:20150781.
1c) Somehow I see certain features only being addressed in one and not the other animal. Of course Livyatan would be very cumbersome compared to an extant raptorial odontocete that is only a tenth its size. But the same applies to C. megalodon compared to an extant shark. Is there any evidence suggesting that general cetaceans are in some way less suited to athleticism at large sizes than sharks? This certainly cannot be observed in the extant world, but at similar sizes, orcas seem to be just as athletic as sharks. And orcas actually operate as active, apex predators at sizes actually not reached by any raptorial sharks today.
Why should Livyatan be slower and less maneuverable compared to an orca than C. megalodon would be compared to a great white shark?
1d) The frequently repeated statement that large bull orcas become slow and cumbersome compared to females. Let’s trace that claim back to its root, shall we? Please feel free to add further evidence, but let me explain why I think that is besides the point:

source: Ford et al. 2005

Nothing at all in here applies to whales, or an orca-like body shape (apart from disproportionately large flippers and fin) in particular.
It it suggested that larger size and proportionately larger fins make male orcas less maneuverable and efficient swimmers than females. That, I think, is a reasonable assumption. But as to its bearing here:
Firstly, isn’t C. megalodon the one that has repeatedly been suggested on here to have had proportionately larger fins? Supposedly to aid in mobility, not hinder it, although that might seem more than a little dubious at this point and is entirely based on conjecture anyway…
Secondly, I don’t think anybody envisions Livyatan to have had super-sized flippers and dorsal fin like a bull orca. So disproportionately increased drag, apart from what’s normal at its (and megalodon’s) large body size is not an issue here.
Thirdly, there are no active, raptorial sharks that reach comparable sizes to a bull orca. The evidence suggests that they would face the exact same problem a large bull orca faces; that larger animals become less maneuverable. That’s not some sort of peculiarity of the orca’s body shape that makes it especially prone to poor mobility when growing larger (except, again, the secondary sexual characteristics of giant flippers and fin, which we have no reason to assume in Livyatan). Raptorial sharks that size simply don’t exist, that does not at all suggest sharks are better at operating at large body sizes than whales. That would be like saying that birds face less difficulty flying at giant size than pterosaurs, because we don’t have 250kg flying birds to demonstrate the problems faced by a flying animal that large, while we can be certain a 250kg pterosaur would have been a less maneuverable flyer than a 100kg one.

So to sum up, the arguments implying that killer whales, and by inference odontocetes, would get less maneuverable at large size can actually be applied to all animals. If C. megalodon is envisioned like a giant great white and yet as being reasonably fast and explosive, than there is no reason a Livyatan envisioned like a giant orca wouldn’t be as well. The obvious situation is that neither will be as explosive or maneuverable as its smaller extant analogues, but that doesn’t mean that for their size either of these was slow or unagile.

1e) So what this breaks down to is basically that unless extant sharks are superior in maneuverability to extant odontocetes of comparable size, there’s no reason to suggest the situation would be any different between these two. Where is the evidence of that?

1f) An argument that pops up time and time again is that a cartilaginous skeleton is so advantageous for maneuverability in an aquatic animal, without any apparent downsides. First of all, I don’t think that’s biomechanically even possible. Being more flexible always comes at the cost of efficiency in some other regard, most likely strength.

But say this were the case. Then why don’t all aquatic animals simply revert back to cartilage (developmentally, that is rather uncomplicated, certainly not something that could not have evolved within the 50 million years of cetacean evolution if it were beneficial)? And why then is shark cartilage more similar to bone in mechanical properties (Porter et al. 2006)? It seems because a rigid skeleton is simply required for the musculoskeletal system to function effectively, especially at large sizes.

Porter, M. E., J. L. Beltrán, T. J. Koob, and A. P. Summers. 2006: Material properties and biochemical composition of mineralized vertebral cartilage in seven elasmobranch species (Chondrichthyes). Journal of Experimental Biology 209:2920–2928.

Perhaps sharks are more flexible, perhaps they are not, evidence has not been brought forth yet. But either way, I doubt its due to their cartilaginous skeleton, and being more flexible will come at the expense of other factors. So another "its a shark so is more agile"-argument that seems to lack empirical support.

2) Ramming
2a) Being able to ram a small animal and causing some damage is one thing, ramming a sizeable prey item as a way of seriously injuring it (which orcas do, see Ford et al. 2005) is another. Odontocetes have demonstrated their ability to cause serious damage to large animals by ramming. If sharks are really capable of similar feats, that remains to be demonstrated.
2b) As to my knowledge, there is ample, published evidence that sperm whales are especially adapted to ramming and can do so to great effect (Carrier et al. 2002, Panagiotopoulou et al. 2016). The ability to sink a large whaling ship by ramming is certainly impressive, and there is a set of very specific anatomical structures involved (long, stiff, bony rostrum, junk, spermaceti organ). Structures that Livyatan evidently had, but which C. megalodon lacked. Yes, Livyatan had a smaller spermaceti organ than Physeter. I’ve read that time and time again. But orcas, see above, can still ram effectively, and the ramming seems to be done with the junk, not the spermaceti orcan. So once more, if Megalodon was a similarly effective rammer, where is the anatomical evodence from it, or from related extant sharks?
Carrier, D. R., S. M. Deban, and J. Otterstrom. 2002: The face that sank the Essex: potential function of the spermaceti organ in aggression. Journal of Experimental Biology 205:1755–1763.
Panagiotopoulou, O., P. Spyridis, H. M. Abraha, D. R. Carrier, and T. C. Pataky. 2016: Architecture of the sperm whale forehead facilitates ramming combat. PeerJ 4:e1895.
2c) Functional morphology alone is not that complicated here. We have one animal with a wide, blunt, cartilaginous, kinetic chondocranium, another with a pointed bony skull with a sturdy, rigid rostrum and specially adapted cushioning in the form of the spermaceti-organ and melon on top. From that, and in the absence of evidence, how does one come to the conclusion, that to be hit by one would be comparable to being hit by the other? I don’t like to repeat myself this often, but somehow this seems to be too easily overlooked. Even if the impact from any 50 ton animal moving at substantial speed would be devastating, it’s another 50t, highly robust animal it needs to do significant damage to. Both functional analysis and direct observations suggests the odontocete cranium and adjacent soft tissues are very effective for ramming, even against large targets. Neither evidence exists for sharks.

I’m very happy to be proven wrong about the latter, both functional morphology and behavioural observations on this are highly welcomed. But without such evidence, the logical assumption is that the whale would ram much more effectively when faced with a large target.

Attachments:

[Grey]

The probable cumbersome nature of a large megalodon has been adressed several times.

The response was simply to sam1 that the whale was in any case much more agile.

It was simply a reminder that :
- a scaled up orca to 14-18 m is not gonna be agile like a 9 m one, let alone and 5 m one.
- Livyatan wasn't an orca delphinid but a relatively more primitive stem-physeteroid. Using an overgrown orca to judge of the agility of this one is probably not correct.

My opinion has always been they were subject to the same physical constraints and may have been evenly matched in this department.

The keys to this qiestion to me are definitely the bite department and the exact size disparity.

[theropod]

And I was not primarily replying to you, I was replying to various arguments I had read, all in one place for convenience’s sake. I agree with you that a similar-sized Livyatan and Megalodon would be evenly matched in terms of mobility. That is the point I am making. But I’ve seen claims in other places that either (more commonly the shark) of these two would have superior agility, which seems to be based on faulty reasoning, so I addressed these points.

As to Livyatan’s body shape, that’s another variable that makes most of these claims pointless. As you are well-aware, I tend to think that Livyatan would have had greater morphological similarities to orcas, because other stem physeteroids do, and because the preserved cranium does, and because of the ecological similarities between them. But that’s besides the point, as we’ll end up reverting back to delphinids and smaller sharks anyway. Actually, the discussion would look pretty much the same if it were whether C. megalodon or a sperm whale was more agile. Irrespective of their (unknown) morphologies, we don’t know whether Livyatan was more or less agile than a sperm whale of similar size, and we don’t know whether C. megalodon was more or less agile either. Not knowing the postcranium of Livyatan, we don’t know its locomotory apparatus, but based on its jaws, we can certainly assume it was subject to the locomotory requirements of an active predatory lifestyle, just like C. megalodon. On the other hand, no matter what speculative life reconstruction we prefer, looking at it and concluding that the animal was more or less agile based on how bulky it is shouldn’t be an argument in a scientifically informed discussion.

Summary:
A scaled up orca is not going to be as agile as an actual orca, obviously. A scaled up great white is not going to be as agile as an actual great white either. As a baseline, orcas and great whites seem to be similarly athletic at similar sizes. SO if both were scaled up to 50t, that would probably still be the case.
We can’t tell whether Livyatan’s locomotory apparatus corresponded more to a scaled up orca, or a sperm whale, or something entirely different from both, because we have no postcranial remains. But even if we did, we still wouldn’t automatically know whether that would make it more or less agile, because we don’t even know that about extant whales, due to the size difference.
Likewise we don’t know anything about how C. megalodon’s locomotion might have differed from a great white shark, and we don’t know how that would affect its mobility.

[Infinity Blade]

Thanks for the information, wasn’t aware of that. I didn’t do in-depth reading on reliable Blue whale speed records. Still, whether 50 or 30km/h, I find that speed very impressive for animals that large. Based on Williams 2002 (in Ford 2005), this still means blue whales are faster than minke whales, despite being easily 10 times the size. So I think that’s sufficient evidence to suggest that size isn’t really that important in terms of top speed. Maneuverability, obviously, is a completely different story. Just that from this I wouldn’t jump to the conclusion that a 50 ton Livyatan or C. megalodon would be particularly slow.

I wasn't trying to argue they were slow, just that a speed figure for a certain animal(s) was probably too high.

A little off topic, but then if Tyrannosaurus could plausibly reach speeds close to 30 km/h, is it rightly considered to be fast or slow (not as fast as terrestrial animals can be one the one hand, but on the other it seems capable of speeds we consider fast in other animals; i.e. whales)?

[theropod]

That’s certainly not slow for an animal that size. Whether we call it slow or fast always depends on what we use for reference. Compared to JP’s fantasy T. rex that can keep up with a car, or Bakker’s 70km/h ostrich-rex, it’s obviously not that fast. But I never thought those speeds were even a realistic standard to expect from something that big.

I presume there are inherent limitations to terrestrial locomotion that essentially make it impossible for an animal as large as T. rex to be much faster than it (at least without unrealistically large muscles and disproportionately strong bone structure, which would not be evolutionarily viable). The thing is, even noticeable adaptions probably only allow for relatively small gains in speed at such size extremes, which is why on the whole, most large theropods really don’t differ that much in their leg proportions, and also why T. rex probably wasn’t massively faster than an elephant despite its morphology being far more geared towards running.

T. rex is the size of a minke whale though, not a blue whale. I find 30km/h a lot more impressive in a 100t animal than in a 6t animal. On the other hand, it seems aquatic animal in general are usually slower at top speed than terrestrial animals. At least the highest speeds reliably recorded for various taxa (cetaceans, turtles, penguins, sharks…) that we think of as quite fast aren’t really that impressive compared to, say, terrestrial mammals. But perhaps that’s rather an artifact of the difficulty of clocking the speed of aquatic animals, so that record speeds simply aren’t recorded as often.

[Infinity Blade]

Another thing I should address about ramming

As to my knowledge, there is ample, published evidence that sperm whales are especially adapted to ramming and can do so to great effect (Carrier et al. 2002, Panagiotopoulou et al. 2016). The ability to sink a large whaling ship by ramming is certainly impressive, and there is a set of very specific anatomical structures involved (long, stiff, bony rostrum, junk, spermaceti organ). Structures that Livyatan evidently had, but which C. megalodon lacked. Yes, Livyatan had a smaller spermaceti organ than Physeter. I’ve read that time and time again. But orcas, see above, can still ram effectively, and the ramming seems to be done with the junk, not the spermaceti orcan.

I wasn't saying Livyatan wasn't a proficient rammer (in fact, I recall saying regardless of how large its junk chamber was, it was still obviously prominent enough to be used to great effect). At the time I was trying to say that I didn't see ramming as the most defining aspect of this fight, citing the raptorial jaws of Livyatan in conjunction with how, if anything, the chamber was not as large as in Physeter (where ramming absolutely is its most defining/deadly weapon, at least against large animals). Sure, a smaller spermaceti organ may not be relevant (since, as you stated, that's not the real ramming organ), but a presumably smaller junk would be. Again, not at all saying Livyatan was a bad rammer or anything or that it's an ineffective weapon.

Also, this doesn't affect what I said right above, but could someone clear this up for me? Do orcas ram with the tip of the rostrum (like I think is the case with bottlenose dolphins) or with the melon?

[theropod]

^That is a good question, I don’t know any accounts that are detailed enough to tell. Ramming with the rostrum is another possibility, at least against a soft target. Either way, Livyatan is well-equipped for ramming.

Whether or not you see ramming as an important aspect of this scenario is up for debate, my point was simply that there is strong evidence suggesting that C. megalodon ramming something will not be comparable to Livyatan doing the same, while there has been no evidence at all supporting that sharks are capable of similarly potent rams, despite repeated assertions about its ramming capabilities.

[sam1]

Jul 12, 2018 2:41:56 GMT 5 Grey said:

The probable cumbersome nature of a large megalodon has been adressed several times.

The response was simply to sam1 that the whale was in any case much more agile.

It was simply a reminder that :
- a scaled up orca to 14-18 m is not gonna be agile like a 9 m one, let alone and 5 m one.
- Livyatan wasn't an orca delphinid but a relatively more primitive stem-physeteroid. Using an overgrown orca to judge of the agility of this one is probably not correct.

My opinion has always been they were subject to the same physical constraints and may have been evenly matched in this department.

The keys to this qiestion to me are definitely the bite department and the exact size disparity.

A whale/dolphin is inherently more agile than a shark.
I've been repeating this on carnivora, seems like o need to do it again. 
The extent in which the whale can maneuver and control its body simply cannot be matched by a shark.
The ability of hovering + omnidirectional rotation and movement are important aspects of how agile the aquatic organism is overall.

And I've repeated the following even more - bite is of secondary importance if we assume that Livyatan would primarily rely on ramming.

A sperm whale bull could well be toothless and still win against a megalodon.

[prehistorican]

That doesn't really look like what Livyatan would rely on based off of its highly developed bite. Inherently more agile? A sperm whale bull of similar mass win against Megalodon by ramming it? That is quite *interesting* and considering that Megalodon has robust chondocranium it should be able to ram effectively maybe not to the extent of the Livyatan. Unfortunatley for Livyatan, it would mainly have mixture of 2A and 2B muscle, and yet a shark has 90% 2B muscle. Megalodon would probably have a higher top speed than Livyatan. Not only that, it should be able to have a smaller turn radius as it has 200+ vertebrae which is more than the whale. Great whites also have a higher top speed than a bottlenose dolphin. Type 2B muscle reaches peak power production and outputs a higher peak force than Type 2A and B mix. I would very well doubt that whales and dolphins of similar mass at large scales have that much of an agility difference. I don't see dolphins hunting down and chasing down fast agile sailfish such as shortfin makos.

[sam1]

Prehistorican, sorry but I don't see the point in even trying to argue with you.
Just so much bias and things(seemingly deliberately) taken out of context that I simply don't have time nor energy to address.

[theropod]

sam1: Where is the evidence of whales being "inherently more agile"? Yes, I’m afraid you will need to do it again. If you have done it before, reposting it shouldn’t be too much trouble. I don’t read much of carnivora any more, I simply don’t have the time. But in what I have read, I’ve never seen actual evidence to back up these claims. Claiming something is not the same as demonstrating it.

prehistorican: There is no "has a robust chondocranium" here, that is entirely based on conjecture as long as nobody finds a preserved Carcharocles chondocranium. Even with a robust chondocranium, that still does not constitute an adaption for ramming though. Again, ramming a small animal despite not being adapted for it is one thing, ramming another 50 ton animal is an entirely different thing. So saying "the shark can ram too" is only relevant to this discussion if there is any evidence that large sharks actually do ram animals or objects of at least similar size.


One more thing on the agility discussion. I’m not sure whether I have noted this before, but since we would expect a larger shark to have a higher cruising speed to account for its respiratory needs (Jacoby et al. 2015), and since it has to keep moving at that speed continuously, 24h a day, if anything a giant shark would realistically require larger amounts of oxidative/slow-twitch muscle-fibres than a small one. Extant sharks don’t seem to significantly outperform similarly-sized cetaceans in terms of explosive acceleration or maneuverability to begin with, but claiming a giant shark would due to its greater amount of white muscles seems like an even more hazardous claim, considering its respiratory system dictates that it would have to invest less, not more in fast-twitch muscle fibres. So you can think what you want about how much of a benefit larger amounts of fast-twitch muscle fibres would be, but I don’t think that’s relevant as the animal needs to be able to swim relatively fast, and do it continuously. Rapid acceleration is important, but respiration is even more important. So if we assume Megalodon had a cruising speed similar to a fin whale, then it can’t have had superior acceleration due to its large amount of white muscle, because in order to be able to maintain that speed it would have needed oxidative muscle fibres.

[sam1]

Jul 16, 2018 20:14:26 GMT 5 theropod said:

sam1 : Where is the evidence of whales being "inherently more agile"? Yes, I’m afraid you will need to do it again. If you have done it before, reposting it shouldn’t be too much trouble. I don’t read much of carnivora any more, I simply don’t have the time. But in what I have read, I’ve never seen actual evidence to back up these claims. Claiming something is not the same as demonstrating it.

Extensive definition of agility From Wikipedia:

"Agility or nimbleness is the ability to change the body's position efficiently, and requires the integration of isolated movement skills using a combination of balance, coordination, speed, reflexes, strength, and endurance. Agility is the ability to change the direction of the body in an efficient and effective manner and to achieve this requires a combination of:

balance – the ability to maintain equilibrium when stationary or moving (i.e. not to fall over) through the coordinated actions of our sensory functions (eyes, ears and the proprioceptive organs in our joints);
static balance – the ability to retain the centre of mass above the base of support in a stationary position;
dynamic balance – the ability to maintain balance with body movement;
speed - the ability to move all or part of the body quickly;
strength - the ability of a muscle or muscle group to overcome a resistance;
and lastly, coordination – the ability to control the movement of the body in co-operation with the body's sensory functions (e.g., in catching a ball [ball, hand, and eye coordination])"

The only aspects of agility sharks can rival whales or dolphins is speed (angular velocity in particular), change of speed (acceleration), and strength.

In all other aspects whales either trump either completely negate(because sharks lack the ability in the first place) sharks.

Good enough?

[theropod]

I didn’t ask for a definition of agility, I asked for evidence (scientific studies, accounts, video footage…) for your claim that cetaceans are more agile than selachians.

Also, did you notice that three of the six points in your list (balance 1 through 3), which are not aspects of agility but factors contributing to it (slight difference, I know), only apply to terrestrial animals?
Do you have a paper that measured or estimated the angular velocities of sharks and whales? Or the acceleration? Besides, these two seem to be the most crucial points for agility; turning ability and acceleration.