Re: The Torso Tilt and Stiff Tails .-- Function in Locomotion

["Demetrios M. Vital" <vita0015@umn.edu>]

On 17 Jul 2001, JAMES ARONIS wrote:
> In regards to these anatomical modifications, would bipedal dinosaurs be
> considered more efficient runners than ratites, or less? Does the tail
lend
> to
> superior balance, or do these compensations you mentioned that evolved
due to
> the atrophied tail? My main concern in this particular topic regards the
> ultimate speed possibly reached by the ornithomimid dinosaurs. It has
always
> been an area of interest to me.
>
> Thanks.

I don't know about the relative efficiency, and there are many more
educated people in this area onlist than I.  But Tyrannosaurus rex
locomotion has taken a huge chunk of attention lately, so I don't know how
many people are studying ornithomimids.

There's a lot that can't be learned as far as speed from fossils, though.
Ostriches, for example, I learned recently from this list, can run at 35
kmph for up to ten hours!!  That can't be extrapolated from fossils.

I don't know about footprints, either.  I haven't heard of any possible
ornithomimid trackways to date.

This is probably where my knowledge stops and conjecture continues.  Are
there any experts onlist able to answer these questions?

-Demetrios Vital

p.S. When I wrote this:

> "Demetrios M. Vital" wrote:
> > But, like I said, the caudofemoralis changes a lot of things, and I
> > envision the tail shifting laterally over to the side of the leg
touching
> > the ground, and then back, with each step.  So not only does
musculature
> > cause it to shift left and right, it shifts for balance.

I meant that the leg was touching the ground, not the tail.  Thanks for
pointing that out, HP Cunningham.