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Re: Tyrannosaurus arms



Sam Hogan writes:

>OK, I've been out of the Paleontological picture for a while.  Whatever
>happened to the idea that Tyrannosurus used its arms to lever itself up
>from a resting position?

**WARNING: Speculation Ahead!**

I don't buy the "short arms as a crutch while getting up" hypothesis for two
reasons:

First, a common aspect for any bipedal animal is that the center of gravity
will be located roughly above the hips.  Therefore, all that Rex would have
to do to get up is to push up with it's feet (Rex may have pushed both up and
*back* to counter any unstability from that heavy head).

Secondly, if the arms did serve as a crutch, wouldn't there be a selective
pressure for *longer* arms (maybe even a push for a quadrepedal animal)?
 IMHO, the arms are way too short to be useful for this purpose.

Rob Meyerson
Orphan Vertebrate Paleontologist

***
"Spoon!"
        -The Tick