Dakotaraptor
Junior Member
Used to be Metriacanthosaurus
Posts: 193 
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Post by Dakotaraptor on Jun 26, 2013 1:33:03 GMT 5
Who do think about it? According to William Irvin Sellers and Phillip Lars Manning's research Compsognathus may be the fastest dinosaur, being even faster than Ostrich itself (in this study). Despite i would say 6 tonnes T. rex (29 km/h) and 1.4 tonnes Allosaurus (34 km/h) speed are pretty reliable. Although could i say about Compsognathus? Wouldn't it work like "Machine"?  |
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Post by theropod on Jun 26, 2013 1:57:25 GMT 5
I see no reason why it shouldn't have been that fast, it has an extremely light, long-legged built. I don't think that makes it the fastes non avian dinosaur tough, as a bit larger animals (eg ornithomimids which have a similar built) could have likely run even faster. I figured out it must be this way: The fastest animals are neither the smallest, nor the largest, because A: While small endothermic animals have a very small weight compared to their muscular force/cross-sectional area, they also have a lot of air friction, their steps are smaller, and they cannot afford having even more musculature because they already need to eat all the time for keeping their temperature constant B: large animals lack in stability, falls can be deadly and their mass is very great compared to their muscular force. While their step lenght is large, and their air friction minor, they would risk injury by moving very fast, because their structures couldn't support the stresses that are produced, and their muscles are not strong enough to effectively accellerate their mass. I think the reason why its usually mid-sized (50-1000kg) animals that are the fastest ones is that they have bigger stride lenghts than smaller ones, but can still easily pack enough muscles to accelerate and propel themselves, are not as prone to injury as larger ones and make speed a beneficial adaption. Now I'm waiting for coherentsheaf to point out where my flaw is, because I'm almost sure there is one, but I cannot think of another explanation  |
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Post by coherentsheaf on Jun 26, 2013 3:02:24 GMT 5
I see no reason why it shouldn't have been that fast, it has an extremely light, long-legged built. I don't think that makes it the fastes non avian dinosaur tough, as a bit larger animals (eg ornithomimids which have a similar built) could have likely run even faster. I figured out it must be this way: The fastest animals are neither the smallest, nor the largest, because A: While small endothermic animals have a very small weight compared to their muscular force/cross-sectional area, they also have a lot of air friction, their steps are smaller, and they cannot afford having even more musculature because they already need to eat all the time for keeping their temperature constant B: large animals lack in stability, falls can be deadly and their mass is very great compared to their muscular force. While their step lenght is large, and their air friction minor, they would risk injury by moving very fast, because their structures couldn't support the stresses that are produced, and their muscles are not strong enough to effectively accellerate their mass. I think the reason why its usually mid-sized (50-1000kg) animals that are the fastest ones is that they have bigger stride lenghts than smaller ones, but can still easily pack enough muscles to accelerate and propel themselves, are not as prone to injury as larger ones and make speed a beneficial adaption. Now I'm waiting for coherentsheaf to point out where my flaw is, because I'm almost sure there is one, but I cannot think of another explanation This is a pretty good summary of the reasons why we see maximum sprint speed in midsized animals. 64km/h for Compsognathus seems very high though. On the other hand some extinct bipeds were likely very fast, Mesembriornis was estimated to have reached a top speed similar to a cheetah by Farina and Blanco. |
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Post by theropod on Jun 26, 2013 16:42:09 GMT 5
^Yay, I got something related to physics right!
I remember they pointed out their method may produce overestimates (going by what they got for the Moa). Anyway, I agree some extinct bipeds were probably extremely fast.
Not sure about Compsognatus' exact speed but I think it was fast too. A house cat can run at nearly 50km/h if I'm not mistaken, and Compsognatus is of similar size but has much longer legs (merely an analogy for the size factor here, not morphology).
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Post by creature386 on Jun 26, 2013 16:45:55 GMT 5
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Post by coherentsheaf on Jun 26, 2013 16:47:33 GMT 5
^Yay, I got something related to physics right! I remember they pointed out their method may produce overestimates (going by what they got for the Moa). Anyway, I agree some extinct bipeds were probably extremely fast. Not sure about Compsognatus' exact speed but I think it was fast too. A house cat can run at nearly 50km/h if I'm not mistaken, and Compsognatus is of similar size but has much longer legs (merely an analogy for the size factor here, not morphology). I think comparing bipeds and quadropeds in this regard is difficult. The cat has an increased stride between the front legs and the back legs by using its back to propulse itself. Further where is the 50 km/h figure from? |
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Post by theropod on Jun 26, 2013 17:06:57 GMT 5
I admit, that's merely what you read in most places (animal encyclopedias and the like). I meant that as an analogy for size, not morphology. I know it is hard to compare quadrupeds and bipeds in terms of propulsive function, but I tought if a cat can run that fast, a compy could also possibly achieve a speed of 64kph.
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Fragillimus335
Member
Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Jun 27, 2013 1:26:13 GMT 5
I would hazard a guess that 64 might be a bit on the high side, 40-50 kph sounds more palatable.
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Deleted
Deleted Member
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Post by Deleted on Jun 27, 2013 9:50:34 GMT 5
64 kilometers/hour is a bit too fast imo, the stride length must be really pathetic in absolute terms, despite the proportionally long legs.
I say ~45-55 kilometers/hour is more likely.
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Post by creature386 on Jun 27, 2013 13:08:13 GMT 5
Agreed, I can't imagine it to be faster than ornithomimids, which are estimated at a speed of 60 km/h.
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Post by theropod on Jul 2, 2013 0:28:59 GMT 5
I think that figure might be an underestimate. imo if the rhea can run at 70kph (there's a video showing one running the same speed as a car reportedly driving at that speed), Ornithomimids, with their greater size and stride lenght, may be able to be even faster than that, but I admit that's guesswork. They are probably still in the ideal size range for extreme speed, arguably more so than rheas.
Don't ostriches too reach 70kph? If so, I would consider it pretty unlikely ornithomimids were slower than that.
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