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Re: Jobaria and the Elephant Commit Suicide



On Thu, 11 Nov 1999, dbensen wrote:
> >> sauropod would not have to rear up fully for this to be effective.
> Consider the relative sizes of the sauropod and the carnosaur. A pushoff
> gains height for the sauropod, and this makes for quite a landing. If the
> carnosaur had actually tried its entry at this point, the sauropod body
> would've come down right on it.
> 
> Behaviorally, a  better model, I think, would be a horse. Horses rear, and
> can actually go bipedal for a few moments and their rearing behavior is
> used for defense.<<
> 
> But think of how much larger sauropods are than horses!  When a horse rears, 
> the
> worst that can happen to it is it sprains its wrists if it comes down wrong.  
> A
> sauropod, however, would be putting incredible stresses onto its fourlimbs 
> when it
> came back down.  Could the bones in its arm take the sudden compression?

The more pertinent and preceding question is: Could the hind legs FIRST
support the weight? The jobaria web page indeed answers that part, and
states:

 But could its main hind leg bone - the femur - withstand
 the bending force generated by the hind leg stand? Or
 would it snap? Using a computer-modeled sauropod
 and a bent-knee pose similar to that of an elephant (shown
 in the illustration here), Jeff Ogradnik was able to show
 that the bones of Jobaria were up to the task. It would
 take a mass almost three times greater to snap Jobaria's femur.

Offhand I'd say yes, the forelimbs could take it.

> Don't forget, rearing up gives the impression of being larger. Many
> animals do the equivalent - like raising fur or having a mane.<<
> 
> As if sauropods needed to be any larger.

Many animals have such displays regardless of the size of the predator.
You also have to consider the effect of a fully reared sauropod(s) on
multiple predators. Now *that* would be impressive.