Re: Speedy tyrannosaurs

[head@lust.isem.smu.edu (Jason Head)]

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