Re: T. Rex

[Stan Friesen <swf@tdat.ElSegundoCA.NCR.COM>]

 >...  I was at a workshop and the presenter brought
 > out the idea that T. Rex was a scavanger, not a hunter.

Yep, this is an idea that is currently being debated.
[Actually it has been in and out of consideration for
many years].

 > The basis was the
 > length of the forearms.  They were supposed to be to short to grasp
 and
 > hold while ripping with the teeth, but were the correct length to
 grasp
 > and turn if the subject was already dead.
 >
 > Anyone hear this theory before?  What is the status on it?
 >
It is very controversial.

But before any progress can be made, one needs to be clear on what
is meant by 'scavenger'.  If you mean an animal that regularly
eats at least some previously dead meat, then every warm-blooded
land carnivore over 50 kg is a scavenger.

If you mean an animal that subsists primarily on previously dead
meat, the question is more interesting.

However, I know of no living scavenger (in this specific sense)
that is both warm-blooded and greater than 50 kg in weight.
[Actually, I am not sure I know of *any* living scavenger
over 50 kg in weight].

Secondly, I am not sure that the arm-length argument is entirely
correct.  true, a *small* prey animal could not be held and bitten
at the same time - but such would probably not need to be held
to be killed.  I *have* done a crude experiment with proportional
models of the relevent dinosaurs, and found that the back of
Triceratops and Edmontosaurus fall almost *exactly* at chest
level on T. rex.   Unless T. rex's neck is rather stiff, I suspect
T. rex could hold either of these species in place in the middle
of the back and be able to bite the neck quite nicely, thank you.
And with Triceratops, holding the beastie *rigid* while killing
it could be a life-or-death matter, given those nasty horns.

My hypothesis is that the short, strong, front legs of T. rex
were for holding Triceratops in a position where it could not
bring its horns to bear while being killed.

It would be helpful to do my model mathc-up with properly articulated,
naturally flexible, models, to see what T. rex could actually have
done.  [This is beyond my current resources to do, sigh].


swf@elsegundoca.ncr.com         sarima@netcom.com

The peace of God be with you.