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Re: Jobaria and the Elephant Commit Suicide

from the footage supplied on the Jobaria website of rearing

"Angus" reared on the back legs by first squatting (by shifting his
weight back and lower-bending the knees slightly), then he held this
position while he lifted the front legs up clear of the ground.  He used
a similar method to balance on his front legs only.

In both cases he assumed a near-rearing position first as a quadraped
and then lifted his legs off the ground with minimal shift to his weight
from the 4-legged position, probably to reduce muscle stress as well..  

This was an animal being slow and careful though, and I don't know what
an animal that was doing this in response to such day-to-day survivial
stimulus as a big Allosaur trying to eat him would do to make this
quicker.  It would probably increase muscle stress whatever it was since
it would be a MUCH faster movement.  A rear by a sauropod would probably
be under the animal's full control and very similar to Angus' methods
however if it reared to mate.

-Betty Cunningham

"k. clay" wrote:
> I have always thought that elephants bend their knees and hips when rearing, 
> not
> so much as a response to their joint morphology, but as a way of shifting 
> their
> center of gravity backwards.  With some sauopods, their centers of gravity are
> over the hips thus making the leg bending unnecessary, although I suppose if 
> the
> hip adductors do get stretched  toward the end of the rearing it may 
> necessitate
> some hip flexion.  I would expect a Triceratops, if it could rear up, would be
> forced to bend its legs like an elephant since it has a similar center of
> gravity.  All criticisms welcome (I have developed a thick hide along with my
> gray hair).--Ken Clay, M.D.

Flying Goat Graphics
(Society of Vertebrate Paleontology member)