Ngandong tiger vs Smilodon populator ~

[blaze]

I compiled some data from Merriam and Stock (1932).

To eliminate a bias imposed by the different shape of the cross-section of their teeth I used the anteroposterior and mediolateral diameters to estimate their circumference.

On average the circumference of the canines of Panthera atrox is 22.6% of condylobasal length. In Smilodon fatalis this percentage is 33.9%. The teeth of Smilodon are proportionally much thicker.

What about absolute terms? The canines of the largest Panthera atrox in this sample, the exact same specimen that Christiansen and Harris (2009) estimated at 350kg, is 99.7mm, below the average of the whole sample of Smilodon fatalis specimens (104.1mm), this despite the fact that this hypothetical average would correspond to an skull only 308mm in CBL, way smaller than the 410mm of that large P. atrox.

On average the canines of S. fatalis are 42.1mm in AP and 20.6mm in ML, in P. atrox it is 28.9mm and 21.2mm respectively.

[Vodmeister]

Dec 8, 2014 2:17:47 GMT 5 malikc6 said:

Don't you guys think the Sabre tooth cat's long teeth would break in this fight? I honestly feel like those are vulnerable for chipping and breaking, especially when in a intense fight and a fight like this would be anything but easy.

This is a bit of a myth. I remember a study which stated that smilodon's fangs were quite resistant to bending forces, and a lot more durable than we give it credit for.

[Infinity Blade]

Godzillasaurus: I think you've got a point on the first part. As for bone penetration, yes, tiny indentations are extremely insignificant, but some of the instances mentioned here seem to be much more than that (ex: the punctured Nimravus skull).

blaze: nice .

[guategojira]

Dec 9, 2014 0:21:04 GMT 5 blaze said:

According to Mauricio Anton, in his blog, there are skulls of Smilodon and dire wolves with clear saber punctures, maybe when hunting did Smilodon care about being delicate with their teeth but it seems that doesn't appear to be the case when it came to killing competitors.

guategojira

Using the formulas of Van Valkenburg (1990), Legendre & Roth (1988), Sorkin (2008) and Christiansen & Harris (2005; 2009) the smallest and the largest Ngandong specimen were of 143 - 368 kg

Hi! it's been a while. On topic why Sorkin (2008)? he presents no formulas, resorting to simple isometric scaling using data from the literature.

Anyway, what equation gave you 368kg? Christiansen and Harris (2005) femur length and femur articular width equations give only 300kg and 214kg respectively for the owner of the large femur. I tested them with their tiger sample an found that on average the actual weight was 13.3% greater than the mean of the two equations (254kg in this case), thus an estimate of ~290kg (range 270-320kg) for the owner of the giant femur.

Said femur is very long yes but it is very gracile, you had already compared its distal width against those of Christiansen's and Harris (2005) sample and came out ok but you didn't realize that you were comparing distal width to articular (trochlear) widths thus exaggerating the actual relative thickness of the giant femur. The correct value for comparison is easy to estimate from the photos though, ~84.8mm or 17.67% of the total length, compared to 18.84% +-0.63% mean of the sample, all the tigers fall close to or within one standard deviation but the Ngandong tiger femur is pushing two standard deviations despite the impression of great size conferred by its length, in fact it is only 4.4% wider than the femur of the 225kg tiger.

The original photo comparison of the humerus I think is unfair to both tigers, first, because while that Siberian tiger humerus is very long, it is gracile, the other Siberian tiger humeri in Christiansen and Harris (2005) had greater shaft circumference despite being 1 and 2cm shorter, so yeah the Ngandong tiger humerus is big and more robust than the one in the comparison... but probably no more robust than the shortest, stoutest Siberian tiger humerus in Christiansen and Harris (2005).

Hi Blaze.

Why Sorkin (2008)? Well, the “simple isometric scaling” is in fact, a formula like any mathematical operation, but I used it because at difference than Sorkin, I have several direct data from tigers (actually measured specimens) and I don’t used only “literature” data, for example that of Walker’s Mammals of the world.

Although Christiansen & Harris (2009) and Sorkin (2008) used the same formula of isometric scaling, both used different ways. Christiansen used a database from real animals with direct measurements and weights, then he get the average of all those values and that was its result. The problem was that his specimens were captive and in the case of the tigers, the large specimens were “light” in comparison with similar sized animals from the wild. In order to compensate, I used the method of Sorkin, which was to use the maximum values available in the records.

When I used the formula of isometric scaling, using the specimens of C & H (2009), the resultant value was of 372 kg, for the large femur. When I used the way of Sorkin (2008) the value was of 364.3 kg (a lower value, which I was surprised). The average of these two results was the figure of 368.2 kg, which seems high but at the same time reliable, for an animal of such a size (relative smaller modern tigers have been known to reach 320 kg in reliable records [Smythies, 1942]).

On the use of the formulas of Christiansen & Harris (2005), in fact, it was a mistake in my post, I did not use them anymore in the final results (check the link provided). Why? The problem is that we don’t know the real measurements of those particular parts of the bone that are needed to use in the formulas, so the use of the length “only”, or “inferred” wide parts, will be incorrect. I was aware of the mistake, that is why, when I conversed with Tigerluver (another great poster and a Biology student), we get to the conclusion that only with the direct measurements of the bones, the formulas will be reliable. In this particular case, the results made by the formulas of Christiansen & Harris (2005) are unreliable, as are based in mere speculation of the wide in the bones, even worst, the pictures used are twisted, so even my corrections in the images could be incorrect.

Other thing is that the “gracile” form of the femur have several explanations, the simple one is that it seems that in fact, all tigers have “gracile” bones in comparison with other Panthera members. Of course this doesn’t mean that the bones are more "fragile", as we don’t know if the bones could be more dense in comparison with the other Panthera.

Finally, in the comparison image presented here, the goal was not the get an accurate comparison, but it was made just for “fun”, just to see if the bones were or not wider. If you are trying to get a conclusion based on it, you are losing your time. To be sincere, I don’t even know why those images are here…

Robust or not robust, weight is not that simple, that is why is a tricky business. If not, check how many problems caused the formulas of Anyonge (1993) and his exaggerated results?

Based on the data, that particular specimen of Ngandong tiger (the femur) was a large (in body size) specimen, heavy or not. However, we must take in count that from only 7 specimens, there is already a "giant" in the game. This suggests that this “giant” was probably not a giant in any sense, but only an average sized specimen, in comparison with other Ngandong specimens that were not conserved in the fossil records. The probabilities to found a giant specimen of a population are huge, so this femur only suggest how large could be those tigers, as probably they were even larger than what we know now. Great examples of this are other Paleontological founds, like the Tyrannosaurus rex, Giganotosaurus carolini or even Spinosaurus agyptiacus. This last dinosaur is a perfect example of what happen when those large specimens are forgotten with time, but when they are “re-discovered”, they produce surprises.

Please, visit the new forum: wildfact.com/forum/

There we are on more information of this large tiger and several other animals.

[blaze]

Isometric scaling doesn't take into account allometry, when there is no other option I'm fine with it but not when we have good regression equations available. Why did you drop Christiansen and Harris (2005) equations? we do know that the length is 480mm there's no uncertainty there, the articular width is true but we know how they measured it and we have photos that we can use, yes they suffer from perspective distortion but it shouldn't make much of a difference because that measurement and the one we know for certain (88mm distal femoral trasversal width) are on the same plane and even if you don't accept that, taking 88mm as the articular width would only increase the estimate from that equation by 21kg, the way I estimated then would go up to 300kg (280-340kg).

The femur is long but there no denying that it is very skinny, even when compared to the already seemingly gracile tiger femora, however given how the difference in size is not that great in this case, isometric scaling might not do so bad so lets test it. Using Christiansen and Harris (2005) sample of tigers I get that in average for both femur length and width, the actual weight is ~98% of the estimated weight but in the case of that femur the two results are far apart at 348kg and 287kg, changing to the mean of both results we get that on average the actual weight is 2.8% more than the estimate which suggests a weight of 327kg (range 295kg-343kg)

For you to have gotten 370kg right out of the bat I suppose you have more data of weight and bone measurements of other, seemingly fatter/heavier tigers? and here I was thinking Christiansen and Harris (2005) tigers were overweight for being captive. I think this is the main problem, yes, there were records of 320kg tigers but wasn't it a cattle killer (so overweight)? and the other includes stomach contents. Physical condition plays a big role when comparing weight, Jaipur wasn't any bigger than that cattle killer wasn't it? but it still weighed close to 200kg more, all fat in its belly and IIRC from Wood (1978) there are other records of tigers as big (dimensions-wise) as that cattle killer that weighted some 260kg or so. This reminds me of bears, two identically sized individual (dimensions wise) weighted at different times of the year might differ by as much as 30%.

I still personally think this tiger was rather long in the back leg and see this specimen as around 300kg in "meh" condition, neither skinny nor overfed. My own estimate for the owner of the humerus is 270kg but I haven't estimated the other elements, it was a big cat without a doubt, is just that I don't agree it could have pushed 400kg.

Edit: I now get what you mean by uncertainty. The fact that the original measurements were taken with less reliable devices, I think Tigerluver exaggerated a bit, the width, said to be 88mm could actually be anything between 87mm and 89mm yes, therefore the articular width I got could be anything between 84mm and 86mm, is it big? yes, very big? not really, the resulting estimated weight discrepancy is of just 20kg using a regression equation using just the 5 tigers in Christiansen and Harris (2005), similar to that made by Tigerluver, I think taking the average is good enough, it also implies just rounding up the number I previously got.

Edit2: Tigerluver does things the way I like them lol I noticed that he has the actual book and uploaded a proper scan of that page but he isn't considering some things, he is still confusing greatest distal width with articular width and measured it from the wrong view, anterior rather than posterior as shown in figure one of Christiansen and Harris (2005), and he isn't considering that von Koenigswald photo itself might suffer from perspective distortion as an explanation of why he got 107mm distal width instead of the measured 88mm, that to me sounds like a better explanation than von Koenigswald measuring some unseen points at the bottom of the femur or above the throclea which are certainly very weird places to measure and not what one would thing of when reading "transverse distal diameter of femur".

Edit3: I'm starting to think that the articular width the way measured by Christiansen and Harris (2005) might be equivalent or roughly equivalent to distal width in the case of the femur but I'm not sure.

[theropod]

Dec 9, 2014 3:45:01 GMT 5 Godzillasaurus said:

Theropod, I don't think a large size means anything when it comes to prevention of breaking: the "adult" teeth of mammals like humans and dogs are designed to be permanent regardless of size. In fact, a longer tooth length would make them much more vulnerable when it comes to fighting

Of course large size means something. If this wasn't the case, that would be the equivalent of an elephant tusk being more fragile than a human tooth, just because it's longer.

Larger size means larger crossections, which can withstand larger loads. This is only overcome in bending strenght, if a disproportionately large moment arm is used. But that does not apply to force vectors attackint closer to the tooth base.

[Godzillasaurus]

Well that also depends on natural shape inherently. Smilodon's maxillary canines clearly were not designed for fighting, but rather killing (I would suspect that its forelimbs were used in head-to-head conflict); and the same can be said about the canines of all felids in particular.

[theropod]

Not sure what relevance that is supposed to have then. The point is that Smilodon’s teeth on the whole would probably (I’ll admit I didn’t calculate it, I’ve had enough integrals for half a year this week) have lower bending strenghts, at least mediolateral, than a pantherines, mainly because they are much longer but not really any wider transversely (tough deeper rostrocaudally).

But since they are so thick, that doesn’t mean they would be more susceptible to breakage in every situation, only if force was applied somewhere near the tips, which would require a pawswipe to specifically aim for them, or at the very least the lower jaw. The relevant crossectional metrics indicating strenght are likely greater than in other big cats, it’s merely that the longer tooth gives better leverage for forces.

So I doubt they are actually all that fragile, and I doubt they are going to snap easily during a fight. On the other hand, I think they are a superior killing weapon as compared to the much shorter conical canines of pantherines, since they actually allow for very deep penetration and, more importantly, inflicting large cuts.

[Deleted]

Smilodon can take it if it is careful enough.

[dinosauria101]

I'd say Smilodon wins more often than not. It's larger and far more muscular, and that will help it.