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Still not a happy camper

The Sellers and Manning paper makes it clear that the modeling of animal 
locomotion still has a long way to go before it produces reliable results. As 
Hutchinson told a reporter, the claim in S&M that Compsognathus was extremely 
is clearly errant. It is not possible for animals much smaller than cheetahs 
and pronghorn to run at very high speeds because they lack sufficiently long 
legs to achieve the very long strides needed to move as very high speeds -- 
there is no way a kangaroo rat for example, much less a cockroac, can run 35 
With its big tail trailing behind and modest length legs little Compy was 
probably little or no faster than a chicken. 

As S&M note, their model is not realistic because it does not incorporate 
elastic energy storage and other factors likely to increase speed in alrge 
animals. In order to get a better handle on matters here is what needs to be 

Model a series of ornithomimids and tyrannosaurids from juvenile to the 
biggest adults -- a juvenile ornithomimids, an adult ornithomimids, a juvenile 
Gorgosaurus, an adult Gorgosaurus, and an adult Tyrannosaurus would cover the 
spectrum. Assume the combined extensors make up 30% of total mass. Also 
assume the highest muscle force values plausible in short power burst, high 
metabolic rate runners (if giant tyrannosaurs were adapted to run, they 
pushed the biology to the maximum the same way the biggest pterosaurs did to 
and whales do to deep dive). Factor in all factors for maximizing speed such 
as elastic energy storage. 

Then see if the ratite and horse sized ornithomimid and juvenile 
tyrannosaurid top speed projections are as high as seen in ratites and fast 
ungulates of 
similar size. Also see if the grown up gorgosaur is at least as fast as a 

As it is digital modeling efforts are of limited value and are potentially 

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