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Re: Jobaria and the Elephant Commit Suicide

In a message dated 11/13/99 1:23:17 AM Pacific Standard Time, 
mbonnan@hotmail.com writes:

> Here's something else to think about.  Maybe the bones can support 3 times 
>  the weight in COMPRESSION (i.e., when they are vertical), but less (I 
>  expect) if they are bent.  Sereno et al. give us restorations of the 
>  elephant and sauropod with BENT knees while rearing

I believe (and correct me if I'm wrong) that the Sereno team's findings 
indicated that the femora were three times as strong as they needed to be *to 
support the animal in the rearing position*.

>  I again emphasize the Caudofemoralis longus tail muscle.  Elephants have 
>  real tail to speak of, yet the tail of sauropods had muscles which were 
>  intimately tied with locomotion.  How are these tail/femur muscles being 
>  accounted for?  If you bend your knees so that the femur swings forward, 
>  far can that muscle stretch?  Would such a muscle restrict how far you can 
>  rear up?  At this point, I am not satisfied with current sauropod rearing 
>  explanations.

I suppose the caudofemoralis would be stretched if the animal were trying to 
sit on its cloaca, human-style, but I think the femur would actually be 
*retracted* to bring a sauropod into the classic rearing pose, since the 
vertebral column would be rotated up to a subvertical position.  The pose in 
which the caudofemoralis really would be stretched is when the animal 
squatted, a position we are now fairly confident at least some sauropods 
could achieve.

--Nick P.