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Re: Speedy tyrannosaurs

At 5:26 AM 9/15/95, Achut Reddy wrote:
>martz@holly.ColoState.EDU (Jeffrey Martz) writes:
>>     Also, although Horner beleives T.rex was a scavenger, I don't think
>>he extends this to mean it was slow moving or sluggish.
>I just re-read Horner's, "The Complete T.rex" and you are right
>about this.  Horner agrees with Jim Farlow's estimates of T. rex
>speed of "twenty-five miles an hour, maybe even thirty-five miles
>an hour", but that anything faster is "highly unlikely".
>What I have a problem with are scavenger theories based on
>obvious errors in analysis or gross misinterpretation of data.
>For example, there are people who believe that T.rex *had* to be a
>scavenger because it was so sluggish it couldn't possibly catch
>anything.  I am not joking:
>       "... _Tyrannosaurus_ was incapable of taking large strides.
>        In fact its stride was not much longer that the length
>        of its foot.  This proves that _Tyrannosaurus_ was a very
>        slow moving dinosaur and not able to walk at much more than
>        5 kph (3 mph), less than the speed of a man walking."
>                        Halstead, L., Dinosaurs, Sterling Publishing Co., 1981
>This from an eminent scientist at the Univ. of Reading.  By looking
>at an actual T.rex skeleton, any six year-old could see the error
>in the above analysis.  A (properly articulated) T.rex skeleton just
>screams out for speed.  T.rex had an exceptionally large area on
>the thigh bones for muscle attachment, allowing for the powerful
>muscles needed to propel it at high speeds.  (Hence, I believe that
>life reconstructions showing thin legs are incorrect, such as the one
>on the cover of "The Complete T.rex"; the thighs and calves should
>powerfully muscled, as in the Battat model).
>If it is true that modern elephants have been clocked at 40 mph,
>I have no trouble believing that T. rex could exceed that, understanding
>that we are talking about short bursts.  Still, the top speed will
>depend on the actual weight which is still somewhat uncertain.  I offer
>the follow estimates depending on the weight of an adult T.rex:
>        Weight          Top Speed
>        ------          ---------
>        4 tons          45 mph
>        6 tons          35 mph
>        8 tons          25 mph

        Hmmm.   What quantitative analyses are you using for both your
speed and weight estimates?

Jason J. Head
V.P. graduate student
Dept. of Geological Sciences
Southern Methodist University
Dallas, Tx. 75275