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Re: Big Dinosaur Print



I am no paleontologist, but I am writing this from the viewpoint of a
mathematician with some background on mechanical system.

T. Mike Keesey wrote, concerning traces of dragged tails:

> Neither Rob nor I are talking of a dinosaur so sick or injured
>as to be unable to move.  After all, that is a trackway along
>which the tail drag is seen.  Just, perhaps, an injured theropod
>was involved.

If the now commonly accepted mode of locomotion, balancing their body
horizontally pivoted on the pelvis, were the only habitual locomation
known to dinosaurs, then I would think an injury that would cause their
tail to hang so low as to be dragged would pretty much lender them
immobile.  Proper balance is one of the most important prerequisite to
mobility and, for an animal which was designed only to be balanced on
the pelvis, losing this equilibrium would be like, fo us, losing a leg.

It seems to me much more natural for paleontologists to accept that
dinosaurs exhibited different forms of walking.  If I remember correct-
ly, horses show about five or six different gaits (e.g., walking,
trotting, pacing, galloping, etc.) and even us humans, even though
we walk 90% of the time, can also run, hop, skip, and (most important-
ly) tip-toe on various occasions.

------------------
Yoe Itokawa -- Fukuoka, Japan
<itokawa@fit.ac.jp>