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Post by theropod on Oct 14, 2019 23:00:30 GMT 5
In British Columbia and Washington 263 killer whales (Orcinus orca) were caught during 1962–73 of which 50 were kept for oceanaria, 12 died during capture operations, and the remainder escaped or were released. Peak cropping years were 1967–70 when 77% of all whales removed from the water were taken. Lengths of cropped males were 2.49–6.98 m and females, 2.80–6.25 m. Of 28 females taken an estimated 43% were mature and of 30 males, 20% were adult. The equation relating body length in centimeters and weight in kilograms is W = 0.000208 L2.577. Revenue to netters from the sale of 48 killer whales is estimated to be about $1,000,000. Of 48 whales held in captivity 48% were still alive on April 1, 1974. Survival to the end of 2 yr in captivity is 75% in whales thought to be immature and 13% in adults. The history, capture localities and techniques, and management regulations of the killer whale fishery are also described. Bigg, M.A. and Wolman, A.A. 1975. Live-Capture Killer Whale (Orcinus orca) Fishery, British Columbia and Washington, 1962–73. Journal of the Fisheries Research Board of Canada 32 (7): 1213–1221. www.nrcresearchpress.com/doi/abs/10.1139/f75-140?journalCode=jfrbc#.XWZ4OaaxWWsThe length-weight regression is based on a sample of 16 male and 16 female killer whales ranging in size from ~2.7 to ~7.0 m. 11 of these individuals are probably adults, based on the cited maturation lengths of 4.9 m for females, 5.8 m for males. At these maturation lengths, the masses predicted by the formula are 1781 kg and 2751 kg. Adult masses interpolated for the studied size-range: 5m: 1876 kg 5.25m: 2128 kg 5.5m: 2399 kg 5.75m: 2690 kg 6m: 3002 kg 6.25m: 3335 kg 6.5m: 3689 kg 6.75m: 4066 kg 7m: 4466 kg |
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Post by Grey on Oct 14, 2019 23:14:27 GMT 5
Hmm other than the lethality of ramming and technicity of orcas, I do think of the girth of the orca as the decisive advantage against a smaller white shark.
This is why I doubt about the relevance about "skull length=>ability to kill a white shark".
In short, I agree that at similar size, a Livyatan would be more dangerous to a meg than a FKW to a GWS but less dangerous than an orca to a GWS.
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Post by theropod on Oct 15, 2019 1:03:09 GMT 5
Nobody ever suggested that. What I suggested was exactly this, "that at similar size, a Livyatan would be more dangerous to a meg than a FKW to a GWS" See for yourself: theworldofanimals.proboards.com/post/47509/threadAll I wrote was strictly about jaw size, and I think I made it clear that both analogues are problematic. So with FKW vs GWS being repeatedly named as a good analogue for this matchup by both you and elosha11, and you yourself repeatedly pointing out bite size as what you consider a key advantage of the shark, you can hopefully see why I felt the need to point out that this analogy doesn’t reflect their relative jaw sizes. Great whites’ alledged predation on FKWs (likely to involve a shark significantly, potentially several times, larger than the whale) is not really more relevant here than orcas’ predation on great whites. Of course both can give us valuable insight into how they might go about attacking the other respectively (at least if an actual observation of how great white sharks attack false killer whales is ever actually made), but they don’t tell us which one would be more likely to succeed in this, as both analogues are biased with respect to the actual animals being compared here. Another point was to bring the jaw size comparison on some even footing. As you will no doubt agree, Livyatan and megalodon have vastly different jaw morphology and jaws adapted to have vastly different functions, and as you probably would not agree, I think this makes a meaningful comparison of the two very hard. So I used a known, extant animal with a much more similar craniodental morphology and function, and of which we know some of the capabilities to see how Livyatan measures up. At the very least, this implies that since an orca is capable of biting a white shark (Pyle et al. 1999), and since Livyatan’s jaws are similar in size compared to megalodon as those of an orca compared to a white shark, that Livyatan would be able to do so as well. Certainly relevant, as I’m sure to have read suggestions that Livyatan would have trouble even biting, or if it managed to bite, causing meaningful damage to the shark. If this is the case, we would expect orcas to also struggle to do so with great whites (or other animals similar in size to great whites), the jaws of an orca, again, being similar in size compared to a great white as those of Livyatan compared to megalodon. That an orca is overall a larger animal doesn’t change that. Of course that gives an orca advantages that a smaller animal would not have, there is no question about that. Obviously this makes an orca much stronger, and much less vulnerable, than it would be if it were the same size as the shark. But the result is that orcas prey on great white sharks, and can quite literally ragdoll them due to their size and strength. Really, I thought it rather obvious that wasn’t what I’m suggesting would happen here. |
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Post by sam1 on Oct 15, 2019 12:02:42 GMT 5
Bigg, M.A. and Wolman, A.A. 1975. Live-Capture Killer Whale (Orcinus orca) Fishery, British Columbia and Washington, 1962–73. Journal of the Fisheries Research Board of Canada 32 (7): 1213–1221. www.nrcresearchpress.com/doi/abs/10.1139/f75-140?journalCode=jfrbc#.XWZ4OaaxWWsThe length-weight regression is based on a sample of 16 male and 16 female killer whales ranging in size from ~2.7 to ~7.0 m. 11 of these individuals are probably adults, based on the cited maturation lengths of 4.9 m for females, 5.8 m for males. At these maturation lengths, the masses predicted by the formula are 1781 kg and 2751 kg. Adult masses interpolated for the studied size-range: 5m: 1876 kg 5.25m: 2128 kg 5.5m: 2399 kg 5.75m: 2690 kg 6m: 3002 kg 6.25m: 3335 kg 6.5m: 3689 kg 6.75m: 4066 kg 7m: 4466 kg Off topic but, this indicates a 9.8m(highest recorded orca lenght) weight of around 11000-12000kg. So assuming the reported weight for the specimen is true, it suggests it was an underweight individual. |
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Post by Grey on Oct 15, 2019 12:14:15 GMT 5
Nobody ever suggested that. What I suggested was exactly this, "that at similar size, a Livyatan would be more dangerous to a meg than a FKW to a GWS" See for yourself: theworldofanimals.proboards.com/post/47509/threadAll I wrote was strictly about jaw size, and I think I made it clear that both analogues are problematic. So with FKW vs GWS being repeatedly named as a good analogue for this matchup by both you and elosha11, and you yourself repeatedly pointing out bite size as what you consider a key advantage of the shark, you can hopefully see why I felt the need to point out that this analogy doesn’t reflect their relative jaw sizes. Great whites’ alledged predation on FKWs (likely to involve a shark significantly, potentially several times, larger than the whale) is not really more relevant here than orcas’ predation on great whites. Of course both can give us valuable insight into how they might go about attacking the other respectively (at least if an actual observation of how great white sharks attack false killer whales is ever actually made), but they don’t tell us which one would be more likely to succeed in this, as both analogues are biased with respect to the actual animals being compared here. Another point was to bring the jaw size comparison on some even footing. As you will no doubt agree, Livyatan and megalodon have vastly different jaw morphology and jaws adapted to have vastly different functions, and as you probably would not agree, I think this makes a meaningful comparison of the two very hard. So I used a known, extant animal with a much more similar craniodental morphology and function, and of which we know some of the capabilities to see how Livyatan measures up. At the very least, this implies that since an orca is capable of biting a white shark (Pyle et al. 1999), and since Livyatan’s jaws are similar in size compared to megalodon as those of an orca compared to a white shark, that Livyatan would be able to do so as well. Certainly relevant, as I’m sure to have read suggestions that Livyatan would have trouble even biting, or if it managed to bite, causing meaningful damage to the shark. If this is the case, we would expect orcas to also struggle to do so with great whites (or other animals similar in size to great whites), the jaws of an orca, again, being similar in size compared to a great white as those of Livyatan compared to megalodon. That an orca is overall a larger animal doesn’t change that. Of course that gives an orca advantages that a smaller animal would not have, there is no question about that. Obviously this makes an orca much stronger, and much less vulnerable, than it would be if it were the same size as the shark. But the result is that orcas prey on great white sharks, and can quite literally ragdoll them due to their size and strength. Really, I thought it rather obvious that wasn’t what I’m suggesting would happen here. There is something to note though, Livyatan jaws are certainly the most impressive among any tetrapods but for the same skull length, they are still narrower than those of orcas and FKW. Unless I have a false perception. I would not be surprised a 6 m orca to have a wider and possibly at least as voluminous bite size as a 5.3 m GWS, not so much with Livyatan as the comparison between two reasonable reconstructions shows (Livyatan reconstructed skull vs life size meg model at the Smithsonian). This limits further the comparison with GWS and modern delphinids. Biomechanism of Livyatan's bite would be necessary to further compare it with modern orcas. |
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Post by sam1 on Oct 15, 2019 13:53:00 GMT 5
Grey you missed to answer my question about the mean figure of adult megalodon TL. Instead you throw the sudden emphasis on the orca-livyatan analogy. I don't see much relevance here. Unless I'm missing something, isn't orca VERY differently proportioned than Livyatan anyway? The livyatan skull is a lot bigger proportionally..if the holotype had the same SL:TL ratio as orca, it would've stretched to over 21m. So yeah, the holotype at 15m has proportionally a lot bigger skull, as well as teeth. Also, livyatan temporal fossa seems much more developed than that of an orca. With all this in mind, as theropod noted, orcas definitely don't have trouble biting through sharks..unless it happens on a daily basis, as indicated by north Pacific offshore orcas likely specialize in shark predation. www.google.com/url?sa=t&source=web&rct=j&url=https://www.int-res.com/articles/ab2010/11/b011p213.pdf&ved=2ahUKEwjjueTH8J3lAhUVIMUKHepoCwEQFjAAegQIBBAB&usg=AOvVaw1G62Q4o0RdeYwfGGlcB2Zx |
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Post by theropod on Oct 15, 2019 14:07:12 GMT 5
There is something to note though, Livyatan jaws are certainly the most impressive among any tetrapods but for the same skull length, they are still narrower than those of orcas and FKW. Unless I have a false perception. I would not be surprised a 6 m orca to have a wider and possibly at least as voluminous bite size as a 5.3 m GWS, not so much with Livyatan as the comparison between two reasonable reconstructions shows (Livyatan reconstructed skull vs life size meg model at the Smithsonian). This limits further the comparison with GWS and modern delphinids. I don’t think so.
Scaled to the same condylobasal length, the metric I used for comparison:
 The Livyatan skull and jaws are at least as impressive at the same size. You keep pointing out how much more voluminous megalodon’s bite supposedly was as a key advantage, now you want to tell me the orca’s jaws pictured above would be even more voluminous than that? The orca’s bite wouldn’t even be more voluminous than the Livyatan’s, if megalodon’s jaws really are that much more voluminous, then so are the jaws of a great white compared to an orca’s.
Skull length is a good metric for comparison between these two. At similar skull length, the width and bite size of Livyatan and raptorial delphinids is similar.
 If anything, actually measuring the area of the tooth-bearing part of the rostrum, Livyatan’s bite seems to be bigger, largely since it has a longer tooth row than the delphinids. Meaning my previous scaling is conservative. Which is fine, because even being conservative, it still brings the point across. Livyatan bite >> orca bite at total length parity. It was you, not me, who focused so much on bite size. sam1 : The regression equation would indicate 0.000208*980cm^2.577=10628 kg. However, as I noted, the very low exponent is a bit weird, and might have more to do with juvenile orcas being exceptionately bulky than with adults actually getting more slender (seeing how there were no >7 m individuals in their sample, we don’t really know for sure how heavy individuals that large would be). A larger sample, including more adult individuals, would be needed to clarify that. As we have discussed elsewhere though, the 10 t for that specimen may not actually be reliable to begin with. But even so, if mean weight were 11-12 t at that size, 10 t would still be within the range of fairly normal variation. Attachments:
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Post by theropod on Oct 15, 2019 14:52:16 GMT 5
Grey you missed to answer my question about the mean figure of adult megalodon TL. The SVP abstract proposes an "average", but really that appears to be the estimate for the Yorktown dentition (at that time), which I find curious as Grey just spend 5 years arguing that a single specimen could not be automatically considered average-sized…and because it is ignoring that the Yorktown dentition isn’t the only associated meg dentition, but the largest.
Now we can go two routes here. Either, we ignore isolated teeth or we include them. But either way, the Yorktown dentition ends up being a large specimen. Only focusing on dentitions, which I am perfectly fine with doing, the dentition described by Uyeno et al. appears to be slightly smaller, and the dentition listed on boneclones appears to be significantly smaller.
Or including isolated teeth, the majority of them appear to be considerably smaller than those in the Yorktown dentition (the mean for the 138 teeth labeled "A1-A2" in Pimiento & Balk’s dataset is 72.5 mm in CH, 69-71% the size of the Yorktown dentition’s teeth, or around 12 m based on grey’s estimates, around 10.5 based on Mollet et al.’s data). That’s the closest to a representative sample we get).
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Post by Grey on Oct 15, 2019 15:51:03 GMT 5
Grey you missed to answer my question about the mean figure of adult megalodon TL. The SVP abstract proposes an "average", but really that appears to be the estimate for the Yorktown dentition (at that time), which I find curious as Grey just spend 5 years arguing that a single specimen could not be automatically considered average-sized…and because it is ignoring that the Yorktown dentition isn’t the only associated meg dentition, but the largest. Now we can go two routes here. Either, we ignore isolated teeth or we include them. But either way, the Yorktown dentition ends up being a large specimen. Only focusing on dentitions, which I am perfectly fine with doing, the dentition described by Uyeno et al. appears to be slightly smaller, and the dentition listed on boneclones appears to be significantly smaller.
Or including isolated teeth, the majority of them appear to be considerably smaller than those in the Yorktown dentition (the mean for the 138 teeth labeled "A1-A2" in Pimiento & Balk’s dataset is 72.5 mm in CH, 69-71% the size of the Yorktown dentition’s teeth, or around 12 m based on grey’s estimates, around 10.5 based on Mollet et al.’s data). That’s the closest to a representative sample we get).
The Yorktown dentition is the largest as a matter of a few centimetres, the Chile specimen gives results of TL only 40 cm less. These two sharks were probably very similar in size although the Chilean set has a proportionately larger lower dentition. There is a private partial associated set in a matrix of rock with teeth almost 18 cm in diagonal length, so I wouldn't consider the Yorktown Formation material as coming from a "large" specimen. I've written multiple times that both could be seen as average as the teeth in it are typical of meg teeth size, with much larger isolated teeth. Didn't I discuss with you about the possibility of Livyatan being an average specimen in pm not a long ago ? |
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Post by theropod on Oct 15, 2019 23:36:40 GMT 5
Please read what I already hinted in my last post. In Pimiento & Balk’s dataset, there are 138 teeth identified as "A1-A2". Of those, 128 also have a reported crown width. Of the former, 14 are larger than the smaller one of the Yorktown dentition’s first two anteriors. Of the latter, 20 are larger than the smaller one of the Yorktown dentition’s first two anteriors. The mean crown width is 76 mm (72% the size of the smaller tooth in the Yorktown dentition), the mean crown height is 73 mm (71% the size of the smaller tooth in the Yorktown dentition).   the blue lines are the sample means, the red lines are the respective dimensions of the Yorktown dentitions A1 and A2.
This doesn’t look like it is "typical", whatever exactly one means by the term. It certainly isn’t average. The upper anteriors are at the 84th percentile in terms of crown width, and at the 90th percentile in terms of crown height, around 40% larger than the sample mean, but at most 20% smaller than the sample maximum.
I note that just days ago you were fine with suggesting the isolated Livyatan teeth tended to be smaller than the holotype’s and suggesting from that it wasn’t "necessarily in the typical size", even though that was a far smaller sample (7 vs 138…), the respective tooth positions are not known, and all of the teeth are within the size range of the holotype’s As for the teeth of Livyatan found here and there, we can't say more since the size is hardly indicative of anything but it remains that all the described until now are in the same size range but still somewhat smaller than those of the holotype. So I wouldn't say it was necessarily in the typical size, maybe in the large typical young adult of its species ? Attachments:megs.dat (17.94 KB)
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Post by Grey on Oct 16, 2019 0:58:33 GMT 5
Total disagrement.
You seem to have somehow forgotten Pimiento's matrix includes neonates and juveniles. The Yorktown dentition has teeth typical of the large teeth from adults. But sure, it is certainly very large compared to the teeth that are closer to great white teeth in size.
There is no more reason to consider the Yorktown meg to be a large adult than the Livyatan holotype and at least we have strong evidence in the form of numerous teeth.
And the measurements of the Yorktown dentition in Pimiento (2010) are not updated. The teeth are actually slightly smaller than in Pimiento's data.
And calm down, your posts are great to read but overly offensive for no reasons since days, I start to lose my interest to discuss further.
Regarding the skull comparison with delphinids, we still don't see the relative width of the jaws compared with the dolphins, only the condylobassal width, that is not what I referred or asked.
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Post by theropod on Oct 16, 2019 4:28:45 GMT 5
You seem to have somehow forgotten Pimiento's matrix includes neonates and juveniles. No, I certainly did not forget that. Otherwise I would have given you a "this is the likely average adult size"-kind of explanation. But we can of course compare the average for the full sample to the average found by the original study for their full sample, and notice some interesting parallels. Based on your estimate the mean figure would be around 2 m higher than Pimiento & Balk’s. Which would still suggest the Yorktown dentition would be larger than the average of the adults. Of course that is not considering the apparent tendency for other datasets than yours to yield significantly smaller size estimates for the Yorktown individual itself (and accordingly, for others scaled from it), which could potentially result in an average figure very close to the one Pimiento & Balk originally published if we were to consider it. Question then becomes, how do you know which teeth are from adults? Luckily, that is a matter of statistics (since there are numerous megalodon teeth, and data on said teeth, available), and can be tested statistically, as I’ve done above. Of course I would be thrilled to see your own statistics showing that the Yorktown dentition is a typical-sized individual, because I’d like nothing more than a shark 17 m+ long on average, but if you won’t show them, then there’s nothing I can do about that. I would not call 80-90% of 138 teeth being smaller than the teeth of the same position in the Yorktown meg "no more reason" than 7 teeth, all of which are comfortably within the size range of teeth in the holotype of Livyatan, but that’s my statistics, let’s see yours! Well interesting. How much smaller, or am I supposed to guess? My post is offensive? What do you find offensive about it? Did I accidentally make up a straw man, or maybe accuse you of personal bias, or remark that your perceived posting tendencies overwhelmingly seem to favour one side? Please, elaborate. Because only 3 days ago I took a break from posting on this very thread because you did all three, and it was me who wanted to give you time to calm down. Since then I have made exactly 5 posts, 4 if we exclude the one where I just quote an older post of mine, which must be the ones that are "overly offensive since days", apparently. So if you find my posts offensive, please tell me what exactly you take issue with, and maybe consider extending me the same courtesy I did you. What is "condylobasal width" and where do you presume to see it in the comparison? What you do see, quite clearly I should hope, is the width of the rostrum, the width between the tooth rows, as well as their length, and hence all the measurements directly relevant to the size of the bite. If that isn’t exactly the comparison you wanted to see, then I am sorry.  Maybe be more specific in what you "ask for" next time, because I didn’t even notice you asking at all, in fact I got the vibe that you were just making a statement that you were already convinced of (namely that Orcas supposedly have bigger jaws and more voluminous bites than Livyatan at the same skull length), not asking for a comparison to test whether or not it was true.
But it certainly is exactly what was relevant to the claim you made, and I would say it pretty conclusively debunks it, unless you can explain to me (or perhaps demonstrate somehow?) how exactly it is you see an orca having a vastly more voluminous bite than Livyatan scaled to the same skull length. |
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Post by Grey on Oct 16, 2019 11:40:27 GMT 5
I won't share unpublished yet data anymore until anything is done and finalised.
You still nit pick in order to debate, the possible size range of the Yorktown meg in our data is well within the adult typical size we find for isolated teeth in the matrix.
I don't see the relevance to ponder on that for long.
Fair enough then, I thought you were somehow vindicative in this discussion.
Am I wrong if I remark that the jaws of Livyatan are narrower than in the orca, especially the mandible ?
But I wonder if the atypical disposition of the teeh, protruding outside the jaws in some reconstructions, does not enlarge the actual bite volume.
A rigorous analysis of the jaws is needed.
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Post by sam1 on Oct 16, 2019 14:55:52 GMT 5
I won't share unpublished yet data anymore until anything is done and finalised. You still nit pick in order to debate, the possible size range of the Yorktown meg in our data is well within the adult typical size we find for isolated teeth in the matrix. I don't see the relevance to ponder on that for long. Fair enough then, I thought you were somehow vindicative in this discussion. Am I wrong if I remark that the jaws of Livyatan are narrower than in the orca, especially the mandible ? But I wonder if the atypical disposition of the teeh, protruding outside the jaws in some reconstructions, does not enlarge the actual bite volume. A rigorous analysis of the jaws is needed. As I noted before, the Livyatan jaws are much LONGER scaled to the same body length. Why are you ignoring that aspect? And the teeth are bigger too, proportionally. If we assume the orca-like SL:TL proportions, Livyatan holotype would scale to over 21m long. |
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Post by Grey on Oct 16, 2019 15:26:26 GMT 5
Uuh I have noted that and talked about it a few posts ago. I know about the scaling with orca but it is irrelevant since Livyatan is not a delphinid. By this criterion, are we going to infer that an adult Brygmophyseter would be more potent and powerful than an orca at parity length ?  |
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