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Post by jhg on Jul 15, 2016 22:08:45 GMT 5
Well, there is no rule that says the popular name can't have something to do with the species name. In fact, there are no rules for popular names. Anyway, the 20 m thing is based upon some very large teeth which have been discussed in our Megalodon size thread. Might be from one collecting social security discounts! Sharks can grow really old. |
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Post by theropod on Jul 15, 2016 23:43:55 GMT 5
Nonetheless, my invertebrate lecturers would probably be laughing off their asses at people discussing the fight between an odontocete and a clam…
And I think we’re back to just stating the obvious here.
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Post by elosha11 on Jul 16, 2016 4:18:28 GMT 5
Clam all the way baby! Megalodon would clamp down on the whale's tail or nose and make it beg for mercy, right before it swallowed Livyatan whole. Megalodon is the all-time terror and plague upon this world... It would eviscerate C. Megalodon for daring to falsely appropriate its name. All Hail Megalodon!  Megalodon clam is the Chuck Norris of the animal world! Megalodon died many millions of years ago, but death hasn't built up the courage to tell it yet.  Megalodon doesn't flush the toilet, it scares the sh*t out of it!  |
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Post by theropod on Jul 16, 2016 14:02:03 GMT 5
^Spoken like a true invertebrate guy.
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Post by creature386 on Jul 16, 2016 14:19:39 GMT 5
Likelihood of surviving a nuclear blast: Megalodon: Greater than 0% Livyatan: No chance COZ MEGALODON HAS A SHELL!!!!! (for those who don't get the joke, search SuperGuerreroXY on carnivora and you'll get the reference  ) |
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Post by jhg on Jul 16, 2016 15:38:35 GMT 5
Pfft. I know something that can take out all three at once- the Ultimate fantasy human(Next Generation):
Mass: 1,300 kg
Height: 8 m
Can run 560 km without rest
Top running speed: 13 m/sec
Longest jump: 10 m
Top vertical jump: 2 m
Can lift twice the mass
Visual acuity: 6/1.5
Intelligence quotient: 200
High creativity
On topic, this one is really a toss-up match and IMO most people would vote C. megalodon only because they know it better. The way I look at it, Livyatan wins through sheer intellect, near equal size, equal aggression and extra mammalian stamina. It's truly indeed an ultimate sea monster fight!
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Post by Grey on Jul 16, 2016 22:35:07 GMT 5
Prehistoric wildlife models are not the best although they have improved a bit with time. 3 tonnes sound realistic though. If Megalodon indeed reached or exceeded 20m TL and was robust like a white shark the neighborhood of 100 tonnes is plausible. 1. That's true but I didn't want to work with nothing. 2. I think only very old C. megalodon got to 20+m. And it's Carcharocles megalodon not Megalodon the same way Homo sapiens isn't Sapiens. "Megalodon" with a capital letter may not be rigorously written but it is used as such by even some scientists themselves and some of the most educated members of this board. Once the species is understood to have topped that size, there's no problem with the fact to use it. Even Gottfried et al. 1996, despite their 'conservative' 16m, 50 tonnes estimate, recognized the species to have reached 20m. This figure has been acknowledged and used in various subsequent works. |
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Post by Grey on Jul 16, 2016 22:43:12 GMT 5
Pfft. I know something that can take out all three at once- the Ultimate fantasy human(Next Generation): Mass: 1,300 kg Height: 8 m Can run 560 km without rest Top running speed: 13 m/sec Longest jump: 10 m Top vertical jump: 2 m Can lift twice the mass Visual acuity: 6/1.5 Intelligence quotient: 200 High creativity On topic, this one is really a toss-up match and IMO most people would vote C. megalodon only because they know it better. The way I look at it, Livyatan wins through sheer intellect, near equal size, equal aggression and extra mammalian stamina. It's truly indeed an ultimate sea monster fight! I question how relevant the sheer intellect would really be in that match. "Near equal size" actually implies here an advantage to Megalodon. If that one really reached or exceeded 20m, which for now is not supported by Livyatan fossils, there is a distinct size advantage to the shark (but here comes the question of how agile would be such an individual). There is no way to estimate the real agression in these animals, or even less in Livyatan. Usually while cetaceans are indeed superior in stamina, they're not ax explosive and maneuvrable as the sharks (lamnoid type). C. megalodon is estimated to have had a cruising speed comparable to the modern fin whale. |
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Post by theropod on Jul 16, 2016 23:40:01 GMT 5
As a side note, that’s the cruising speed dictated (or rather, loosely suggested) by its oxygen requirements. The basking shark has a higher average cruise speed than a shortfin mako, that doesn’t make the former more athletic or a better swimmer of the two, larger animals with ram ventilation merely have higher cruise speeds on average because they have to take in more water to absorb enough oxygen.
Where is the data suggesting odontocetes to be less explosive or maneuverable than lamnoid sharks?
Near equal size" does not technically mean anything except that they are similar in size (which they are, as long as you don’t assume the equivalent of a 1t polar bear being the default representation of its species). "Near equal" doesn’t actually imply which one of the two, is the lesser by the very small amount it does imply, only that they are very close.
And I suppose since the 20m/100t figure ("maximum TL for exceptionately large female megatooth sharks" based on "questionable" sharks according to Gottfried and colleagues) keeps being repeated over and over again as the ultimate argument for why C. megalodon is bigger, we had better start acknowledging that Physeter macrocephalus weighs 132t, that polar bears weigh a ton, and that grey wolves are actually the size of the dire wolves we see in Game of Thrones.
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Post by elosha11 on Jul 17, 2016 7:47:12 GMT 5
It would so interesting if we could get some video of how large sharks interact with similar-sized cetaceans. Not necessarily conflicts, simply interactions. Like how would a 5 meter great white (or a tiger shark) interact with a 5 meter false killer whale, assuming it was not very close to its pod (and the shark was aware of that fact). Would one be more defensive than the other, would one be more aggressive or territorial than the other? Would either of them consider the other a potential prey/predator? The fact that each animal would be dangerous to the other and the fact that FKW's live in large pods probably greatly reduces interactions. But the two animals share a lot of overlapping range, so it's likely there are a great many interactions we never have the opportunity to observe. To me, this is the closest analogue we have to Meg v. Livyatan (of course a FKW isn't really a whale but a toothed delphnid). (I could use the somewhat larger pilot whale, but it's teeth and predatory capabilities probably aren't formidable enough). Orca v. great white is almost a mismatch due to the size disparity, and is nowhere close to a parity contest. But here we have Megalodon and Livyatan, which are close to equal size, with maybe the shark holding a bit of a size advantage. Likewise, the great white seems a bit bulkier than the false killer whale at similar lengths. However, both modern animals have formidable weaponry, both are very powerful and relatively explosive hunters. Probably that's roughly similar to Meg and Livyatan's comparison, of course, on a much larger scale. The very limited evidence of large shark and false killer whale interactions, indicates that large sharks occasionally bite them. We don't know if the bites are predatory or defensive in nature, although on at least one occasion in 2010, the bite marks were on the middle of the cetacean's body behind the dorsal fin, a relatively common place for a shark attack, although the wounds were healing. Here's the pic.  This was off the waters of Hawaii, so the shark could have been a tiger shark, a mako shark, a great white, or perhaps a oceanic whitetip (unlikely as they are usually much further off shore). The bite radius doesn't look all that large, although it's hard to know for sure with only one pic. The FKW looks like a fairly large and robust adult, (perhaps a female with a juvenile next to it?). The researchers described the bite as indicative of a "large shark" "attack" on the FKW. I think the limited evidence is probably more indicative of a predatory attempt, but we have no idea what prompted the bite, how the FKW reacted or whether it counterattacked, whether the pod came to its defense, etc. All we know is that it looks like a probable predatory bite, which might indicate that the shark was, at least at one point, the aggressor. There's a couple other incidents in which shark appear to have bitten and injured FKW's, and one documented account of great whites possibly preying on pilot whales. In general, and with notable exceptions, sharks seem to be the predator/aggressor more often with similarly-sized cetaceans. Great whites and other smaller sharks such as tiger sharks, mako sharks, and bull sharks prey on many species of dolphins and small to medium sized toothed whales (such as pygmy sperm whale, beluga whale, etc) on an occasional, perhaps even semi-regular, basis. Now the sharks probably are generally bigger, but there's quite a few videos/photos of sharks similar in size to the dolphin they are predating. But of course, most dolphins don't have the powerful jaws and teeth of a FKW... Like I said, I would love to see interactions between large sharks and FKW's. I doubt any shark would attempt to prey on an adult FKW except a great white or maybe a tiger shark. Maybe a huge mako could size up a medium sized FKW; they are extremely aggressive and still explosive when they reach huge size. (Discovery's Shark Week recently showed a mako of over one thousand pounds dragging a large boat even when the boat was trying to go the other way, and another one over a thousand pounds exploding in a leap out of the water). On the other hand, we have almost no evidence of FKW's attacking sharks although we know it must occur. Recently, a drone recorded a group of FKW's chasing down and eating a small shark, probably not much more than a meter long. Looked to me like a small whitetip or blacktip shark. It was very interesting, but not very informative for purposes of this debate. Maybe with more and more underwater video and recordings, we will see a true interaction between the two species. And I think it might have quite a bit of relevance to this debate. |
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Post by elosha11 on Jul 17, 2016 8:45:25 GMT 5
^Re above picture, I just emailed the photographer who took it. He's got a weird email app, so hopefully I got it synced up so he can see my question. Here's what I asked him: Dear Captain McSweeney,
I am very appreciative of your research foundation, and the amazing photographs you have taken for Cascadia Research. I have a question about the picture, I’ve inserted below. It’s a picture attributed to you in 2010, from Cascadia Research’s website. It is described as a shark bite mark on a False Killer Whale. The researchers state it’s the first time they have documented a shark bite on a false killer whale. They characterized it as an “attack” by a “large shark.” The FKW in question was catalogued as HIPc127, and the researchers had known of the animal for ten years, since 2000. The web link for this pic is www.cascadiaresearch.org/Hawaii/July2010.htm.
I was wondering if you or any of your colleagues could offer more insight about the picture? It must be an extremely rare event to see evidence of any interaction between large sharks and FKW’s. Do you have any idea how large the FKW in question is? Is it a fully grown adult, and is it male or female? Likewise, do you have any guesses as to the species of shark? Great whites occasionally visit Hawaii to the best of our knowledge, but tiger sharks are more permanent residents? Have you ever heard of large sharks interacting with FKWs on other occasions? I would think even very large sharks would usually be cautious around the cetaceans, since they are also large and powerful predators and live in large pods, unlike the solitary shark. Likewise, I’m sure FKW probably avoid large sharks when possible. I simply find this picture fascinating, since it could be evidence of a complex relationship between the two predators. I have heard of a couple other occasions in which a FKW appears to have been wounded by a shark, but the evidence for the species interaction is incredibly rare. Any insight you or your colleagues have would be most appreciated. Thank you for your time.I'll probably post any response I get. |
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Post by Grey on Jul 17, 2016 9:24:35 GMT 5
As a side note, that’s the cruising speed dictated (or rather, loosely suggested) by its oxygen requirements. The basking shark has a higher average cruise speed than a shortfin mako, that doesn’t make the former more athletic or a better swimmer of the two, larger animals with ram ventilation merely have higher cruise speeds on average because they have to take in more water to absorb enough oxygen. Where is the data suggesting odontocetes to be less explosive or maneuverable than lamnoid sharks? Near equal size" does not technically mean anything except that they are similar in size (which they are, as long as you don’t assume the equivalent of a 1t polar bear being the default representation of its species). "Near equal" doesn’t actually imply which one of the two, is the lesser by the very small amount it does imply, only that they are very close. And I suppose since the 20m/100t figure ("maximum TL for exceptionately large female megatooth sharks" based on "questionable" sharks according to Gottfried and colleagues) keeps being repeated over and over again as the ultimate argument for why C. megalodon is bigger, we had better start acknowledging that Physeter macrocephalus weighs 132t, that polar bears weigh a ton, and that grey wolves are actually the size of the dire wolves we see in Game of Thrones. Good point regarding the basking shark/mako analogy. However, I was not comparing sharks to odontocetes but megalodon to modern equivalentely-sized cetaceans. Whales similar-sized to Megalodon have huge stamina, certainly more than would be a super-sized selacian such as Megalodon but I would expect Megalodon, on analogy with the modern GWS, to be comparatively more explosive and probably more maneuvrable. Of course we're in the realm of speculation here regarding Livyatan. Would it be tonic like an orca or a sperm whale, that's debattable. But I'd give the edge in maneuvrability to the Meg. I still disagree with the approach to willingly ignore larger sizes estimates for Megalodon. I personnally believe Livyatan potentially being 17.5m long but if anything this estimate can be considered questionable itself since based on the upper size estimate of a single incomplete skeleton from a relative. At the same time, by tooth height sizing, you actually don't systematically need the 'questionable' large GWS specimen to get super-sized specimen 20m or more for Megalodon. I've calculated various size estimates for the 168mm high tooth compared to the white sharks specimens in Mollet 1996 (20 specimens) and among them I got at least one specimen at 21m which was not reflected by an especially large white shark, the average size being 16.3m (close to the result obtained by the Gottfried et al. regression). Doing the same calculation but using the upper anterior tooth width (10 specimens) data I even got size up to 23m using one of the 'questionable' specimens (versus 21m using tooth height, Gottfried et al. for some reason used a larger tooth height from this specimen), the average being a bit above 17m. So theoretically speaking, based on tooth size and width, you don't need necessarily questionable specimens to get super-size. Of course the variation is huge, since I got lower sizes at 12 and 14m, based on tooth height and width respectively. But no need of Kanga or Malta to get >20m Meg for a 168mm high, 125mm wide tooth actually. I guess Gottfried et al. overlooked these potential giants specimens while making their equation and only focused on the larger white sharks from their data to get a hypothetical upper size. They also recalled (based on Mollet) that teeth stopping their growth in some of the larger white sharks make any equation from their sample relatively conservative, IMO more conservative than the upper size estimate of Livyatan based on Zygophyseter. Of course the first conclusion is not that this tooth comes from a X-size Meg, rather that the variance is far too vast to be reliable, but if you strictly consider among the potential results, such a size is not represented only by doubtful specimens (and I personnally don't think they are that questionable, especially Kanga). And of course I've not used higher, wider known teeth... Now, if what I suspect and am working on is true, the sum of the tooth width would even more suggest the potential of a number of Megs actually topping 20m, although I still have some data to check... I won't claim anything until that. However, I'm pretty sure that the data of Pimiento et al. 2015 is in jeopardy, crown height equations from Shimada are far from ideal for this species. I'd agree about the similar-size statement as their respective range is roughly overlapping but noting the material potentially suggesting sharks over 17.5m is not that rare from my perspective. Hence for now Megalodon is probably, potentially slightly larger.
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Post by theropod on Jul 17, 2016 17:21:19 GMT 5
Yes, I know you were comparing meg to a fin whale, but nonetheless you posted it on this topic, are you saying you didn’t mean to imply anything related to this topic with it? In any case I don’t think the cruising speed bears any relevance. The much more important question, who sais that GWS are more maneuverable and explosive than comparably-sized odontocetes? I’d be very interested in your data. Up to now, summed tooth width has not been suggesting a large number of potential 20m-candidates. Do you have access to better data on complete megalodon dentitions that invalidate this? elosha11: You say it looks like a predatory bite. Wouldn’t we expect such a bite to be on the ventral side, and most likely on the tail or flippers? I’ve remarked this before, but then that’s because the FKW-GWS comparison has been brought up before, but the analogy doesn’t work if we look at anything except for length. Don’t forget that a hypothetical false killer whale the same length (14.2-17.5m) as Livyatan would have a skull in the 1.82 to 2.25m-range, not 2.94m. The total length of GWS and FKW may be comparable and a good proxy for Livyatan and Carcharocles, but at the same length Livyatan, at any proposed estimate, is a much bigger-skulled, much bigger jawed, and almost certainly much bulkier animal than a false killer whale. The only way this would not be the case would be if you assumed the same proportions as the delphinid, thereby making the whale 23m long. Pseudorca is a formidable predator in its own right, but even if there was a convincing case to be made for great white sharks preying on them, which is still to be determined (Or am I seeing this wrong? We’re talking about two cases of FKWs with bite marks made by a shark under unknown circumstances, of which only one died, and not as a direct consequence of the shark bite), that would not translate to how it would go with a notably more robust cetacean with a 50% bigger jaw apparatus. It’s literally like comparing a cheetah to a leopard. Both are known to take down large prey, they are even similar in mass, not just dimensions (if anything the leopard is smaller). But nobody would suggest that if you pitted them against a hyaena the result would be the same. |
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Post by elosha11 on Jul 17, 2016 22:28:58 GMT 5
^Theropod, I never said FKW v. great white is a perfect proxy contest, just that it's the best analogy we have and that could actually be observed, in theory. Do you have a better analogy? I suspect you believe the whale may have been even heavier at parity lengths than the shark. Would a 1500 pound mako or great white v. a 2000 pound FKW (which would not be fully grown male) be a more accurate contest in your mind? Or a 5000 pound great white v. a 6000 pound orca?
And I don't entirely agree that great white v. FKW predictive outcomes have no bearing on a contest between Meg and Liyatan. It's probably the best analogy because we can have two adult and similar sized predators face off. Each demonstrates predatory behaviors that probably are quite similar in nature to the extinct comparators, the biggest unanswered question being if Livyatan (particularly large males) were solitary or social predators.
But I do appreciate your insight. I knew Livyatan likely had bigger comparative jaws, but i was not aware of the exact dimensions. And you may be right that Livy is comparably more robust than a FKW. That would likely be valuable in a conflict against Meg, although perhaps a FKW at Livyatan length would be "sleeker" and more maneuverable.
As to the bite marks, it's a bit exaggerated now a days to say that sharks always attack from behind and try to cripple the caudal end of its prey. Dolphins often bear scars from attacks to the side and top, as well as the tail and stomach. There was an article showing pictures of bite marks on living dolphins, and I believe quite a few showed bite marks around the dorsal fin area or even attacks on the fin itself. Sharks will opportunistically attack the middle of a large prey's body, if it is the best available option. I'm sure attack patterns are determined by a number of factors, probably some beyond our understanding, and also probably are somewhat random in nature.
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Post by creature386 on Jul 18, 2016 0:04:57 GMT 5
Or a 5000 pound great white v. a 6000 pound orca? Well, his main point was not so much that odontocetes that weigh the same as sharks as a whole cannot be used as a proxy for this battle, his point was about the FKW in particular. Orca vs GWS at parity may be different. Anyway, this reminds me a lot of the debate about the reliability of accounts for the discussion of hypothetical AVA scenarios where we also sometimes ask questions like "Should we work with the best we have or are all accounts we have simply completely unrepresentative?". A similar question could be asked about analogies. I think this is indeed a case where we have to rely more more on our imagination than on actual observations because the FKW vs GWS accounts can only be used as an argument if it can be established why exactly the great white dominates (we need a causation factor that explains the correlation) and see if the same factor can help Megalodon to dominate over Livyatan. |
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