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Post by spinosaurus1 on Aug 2, 2014 0:30:57 GMT 5
its a question that popped up in my mind for a while. is their an equation or study that allows you to calculate the body strength of a dinosaur?
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Post by theropod on Aug 2, 2014 2:34:43 GMT 5
Define "body strenght".
The sum of the absolute muscular force output of all the muscles in its bodies combined? How much stronger it is than a given animal? How much force it could excert in a specific movement with a specific body part?
All of these are very different things.
For example, the strenght of any given muscle can be at least approximated by modeling its size and crossection and multiplying the latter by the average muscle tension of vertebrate skeletal muscle. If you also know the moment arms involved (such as when you know both the approximate size of a triceps muscle and the proportions of the ulna it attached to), that can be used to calculate how much force it could produce.
However real animals are very complex structures and mathematical models describing them are necessarily rough.
The more muscles and bones we are talking about, the more complicated it gets, and there certainly is no simple formula that lets you calculate such a thing as the strenght of the whole body, even though it may be possible to make rough comparisons between animals based on their size and proportions.
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Post by Godzillasaurus on Aug 2, 2014 2:36:09 GMT 5
Not sure, as we don't have much musculature to work with (correct me if I'm wrong, but don't we only have a few imprints of anything fleshy in dinosaurs? I know for one that it is nowhere near as plentiful as teeth and bones). One might claim that square-cube law could mean something, or just a simple size advantage in itself, but that is basically like saying an obese person is stronger then one who is fit and healthy. Simply, I don't believe there is much evidence of dinosaur bodily strength at all (note, we can accurately predict the bite force of many animals given the snout and cranial morphology, but you seem in to be referring to body strength)
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Post by spinosaurus1 on Aug 2, 2014 3:16:12 GMT 5
hmm, I am quite well informed about the square cubic law and the importance of the organisms morphology. it was just a thought that popped. it seems there is just too little material to ever come up with such conclusion.
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Post by theropod on Aug 2, 2014 13:55:14 GMT 5
It’s not just a matter of material, you’d have problems with extant animals whose soft-tissue anatomy is completely known too. they are just too complicated. Godzillasaurus: Muscles rarely fossilise, but the size and shape of the bones and attachment areas can give a clue regarding their size. For example, the size of jaw muscles is constrained by the size of the adductor chamber in theropods–that’s why we are able to estimate bite forces, and this method can be used for other parts as well–and the size of the caudofemoralis is constrained by the caudal and transverse extent of the transverse processes. The problem is that the body has hundreds of separate muscles, and if one wanted to make some sort of overall estimate one would have to do that for every single one, which is often plain impossible. Also, dinosaurs are not obese, so your analogy doesn’t hold, they are just plain bigger (in the way a tiger is bigger than a leopard, not in the way any of the people on the heaviest people-list are bigger than I am). Of course one can use cubic scaling to get simplistic estimates for animal strenght, but whether that’s sufficient depends on the metric we are dealing with. How strong an animal is in what regard of course depends on its size, but also on its morphology. In addition, strenght depends on the way the animal uses it. One animal (e.g. human) may be stronger in terms of lifting weight, but weaker in terms of accelleration. So there really is little basis for comparison here. We are stuck with comparing individual muscles or muscle systems (e.g. jaw muscles, neck, hindlimb, forelimb, tail…). |
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Post by Infinity Blade on Aug 3, 2014 5:43:25 GMT 5
Somewhat related, but I've taken a look at rhino (particularly a white rhino) musculature, and I gotta say I liked what I saw when I looked at the neck and shoulders→. I don't think ceratopsids had musculature quite like that and while going by visuals can be misleading, could it be possible that rhinos (at least the white rhino) would have proportionately stronger necks and shoulders than a ceratopsid? |
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Post by spinodontosaurus on Aug 3, 2014 6:00:08 GMT 5
When comparing animals with such drastically different skeletal morphology, simply looking at the size of the muscles doesn't tell you much. For example, mammals tend to have huge triceps muscles, and much more heavily muscled forelimbs full stop, but it doesn't seem to have made them that drastically stronger than comparatively lightly muscled dinosaurs. I lack the ability to analyse it any further than that though.
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Post by theropod on Aug 3, 2014 15:03:10 GMT 5
I’m not sure whether any rigorous myological reconstruction has ever been attempted for ceratopsids, so we may simply lack the basis for comparison. What they share with rhinos is a very big, heavy head, but the similarities pretty much end there.
Just looking at the exterior size can be misleading. Part of why rhino’s neck muscles seem so big is because the spinous processes on the anterior dorsals are tall, to improve the efficiency of head support by giving it better lever arms, which adds to the visible depth of the structure. If you modeled a similar amount of musculature on a ceratopsian neck, it would still be shallower because it would attach lower on the creature’s back.
Ceratopsians also likely had emphasis on different movements as compared to a rhino, and so the distribution and proportions of their neck musculature would have been different.
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Post by Godzillasaurus on Aug 4, 2014 20:34:06 GMT 5
It’s not just a matter of material, you’d have problems with extant animals whose soft-tissue anatomy is completely known too. they are just too complicated. Godzillasaurus: Muscles rarely fossilise, but the size and shape of the bones and attachment areas can give a clue regarding their size. For example, the size of jaw muscles is constrained by the size of the adductor chamber in theropods–that’s why we are able to estimate bite forces, and this method can be used for other parts as well–and the size of the caudofemoralis is constrained by the caudal and transverse extent of the transverse processes. The problem is that the body has hundreds of separate muscles, and if one wanted to make some sort of overall estimate one would have to do that for every single one, which is often plain impossible. Also, dinosaurs are not obese, so your analogy doesn’t hold, they are just plain bigger (in the way a tiger is bigger than a leopard, not in the way any of the people on the heaviest people-list are bigger than I am). Of course one can use cubic scaling to get simplistic estimates for animal strenght, but whether that’s sufficient depends on the metric we are dealing with. How strong an animal is in what regard of course depends on its size, but also on its morphology. In addition, strenght depends on the way the animal uses it. One animal (e.g. human) may be stronger in terms of lifting weight, but weaker in terms of accelleration. So there really is little basis for comparison here. We are stuck with comparing individual muscles or muscle systems (e.g. jaw muscles, neck, hindlimb, forelimb, tail…). Well you must note a variation in strength among different groups of dinosaurs. For example, it should be well-known that tyrannosaurids were very strong and bulky animals while dromeosaurids on the other hand were actually rather slender and gracile creatures which would have most likely killed prey with quicker slashing and biting. Even though dromeosaurids were much smaller, this too can apply to large theropods in general, specifically when contrasting tyrannosaurids and carnosaurs, with the former being much more powerfully built. There even seems to be differences among families as well, as we can see in allosaurids and carcharodontosaurids, and spinosaurines and baryonychines. Really estimating body strength is in the most premature stages as of now |
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Post by theropod on Aug 4, 2014 22:05:11 GMT 5
That has nothing to do with what I wrote, and it’s actually not that easy to conclude how strong an animal is.
Having a bulky torso isn’t everything, other theropods have more muscle mass in other areas. Dromaeosaurs would be comparatively weak not because they were not strong animals for their size, but because of the square cube law.
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Post by Godzillasaurus on Aug 5, 2014 20:22:34 GMT 5
But square cube law (which I still don't fully understand TBH) simply states that mass increases exponentially as size does constantly, right? This has nothing to do with an animal's overall strength
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Post by theropod on Aug 5, 2014 21:25:56 GMT 5
Mass is size. Lenght increases linearly, area (i.e. muscle strenght at a given thickness) increases to the second power, and mass increases to the third power. But in reality, many muscles experiance what is called positive allometry to somewhat compensate for this, so if a larger animal were scaled down it would be stronger than a smaller one. That is part of why larger animals are commonly bulkier and more robust.
So yes, a T. rex would likely be stronger than a Velociraptor when scaled down to its size, because its muscles would be proportionately more developed to compensate for its larger size in reality. But if a T. rex really were the size of a Velociraptor (or, the other way around, if a Velociraptor were as big as it), it probably wouldn’t be stronger at all, even though there would be differences in built.
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