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Running T. rex (was Re: Incredibly preliminary...)



At 03:51 PM 9/22/97 -0500, Michael wrote:

>>     Probably.  And also, they would not need to run as aften as a
>> predator which also reduces thier chances of falling significantly.
>
>Well, that's likely true.  But elephant don't have any real natural 
>predators left to run from.  However, they did.  Does anyone look at 
>elephantine fossils like Darren does dinosaurs for evidence of 
>falls/trauma? 

That would be an interesting study to see, actually.

>Maybe they did fall more, but that begs the point.  
>They are not anything like a tyrannosaur that would have evolved 
>(presumptively) to survive most falls if it evolved to run fast.

Please, please, please, please READ THE PAPER.  Farlow et al. do not say "no
tyrannosaur could run", or even "no T. rex could run":

>From p. 723 (the Conclusions):

"We think that _Tyrannosaurus_ was an active animal for its size, and we
concur with Holtz (1994 [sic: actual publication date 1995]) that it
probably was capable of attaing faster speeds than equally large theropods
of other clades."

and later

"We also doubt, like Gatsey (1991), that adult individuals of
_Tyrannosaurus_ (our conclusions do not necessarily apply to juveniles)
could run as rapidly as other, smaller theropods, such as ornithomimosaurs,
or even smaller-bodied tyrannosaurs like _Albertosaurus_ (cf. Holtz, 1994
[sic])."

and later

"In any event, our conslusions are, at least in principle, readily
falsifiable.  All it would take is a single trackway of a _T. rex_-sized
theropod in which the stride length is large enough to indicate a very rapid
running speed."

I applaud the authors for describing exactly the test needed by which their
hypothesis can be falsified.

>Or it didn't fall much either, or didn't get hurt as much.  Now 
>that's an opinion, but it makes more sense than anything else, except 
>tyrannosaurs didn't run very fast.  Additionally, look at rhino.  
>They can weigh two tons and are built to take falls.  Do we know that 
>T rex weighed 1.5-4+x this much for sure?  Looks like they did, but 
>no one knows.  I'm not taking sides but pointing out some things, as 
>I suspect we agree more than not about this.

READ THE PAPER!!  Pages 713-716 concern calculating the body mass of MOR 555
(the _Tyrannosaurus rex_ individual they are studying).  The remaining part
of the paper concerns applying these estimates to different models of
falling trauma.  One of the specific comparisons is between rhinos and _T.
rex_!!

>If it's a ball falling to earth then it's easy to work it out.  If 
>it's a living breathing animal reacting to a fall, would it be the 
>same?  How many times to we look at models only to find that they are 
>not supported by the real evidence.  OTOH, if T rex weighs several 
>tons it's going to have immense inertia when it falls.  Now it's 
>a matter of how it falls and how often.  It isn't going to be exactly 
>like an ostrich.

Try (surprise surprise) reading the paper.  It turns out that there IS a
literature on falling trauma, and they construct different models to account
for some of the different factors.

>>      Physics can tell us the forces involved with a given mass hitting the
>> ground; and it can also give us some idea as to the tensile and impact
>> withstanding abilities of tissues.
>
>Yes, but not in a T rex and not in a T rex running and falling.  

Try... oh, I guess I made my point...

(and so no one has to look up the ref data, it is:

Farlow, J.O., M.B. Smith & J.M. Robinson.  1995.  Body mass, "strength
indicator", and cursorial potential of _Tyrannosaurus rex_.  Journal of
Vertebrate Paleontology 15(4): 713-725.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661