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Re: Jobaria and the Elephant Commit Suicide



On Fri, 12 Nov 1999, Matthew Bonnan wrote:
> [...]
> Richard Travsky adds:
> >AN elephant merely provides a physical model for the behavior.
> 
> Okay, but here we must be extremely careful.  Despite all the functional 
> stuff I could throw in here about elephant skeletons differing from 
> sauropods (and you would all sigh and kill me), what elephant are talking 
> about?  African, Indian, what species, what geographic range?  It is very 

The jobaria web page specifies Sereno had access to a 20 year old African
elephant named Angus.

> easy to go from using an elephant as a useful yardstick to jumping to 
> conclusions about specific behaviors.  Just because Jobaria or other 
> sauropods "look" like they're designed to rear up doesn't mean they did, 
> whatever you compare them to.

The jobaria web page does give some insight into this. They calculate
the hind limbs could support three times the animal's weight.
 
> Richard Travsky adds further:
> >Don't forget, rearing up gives the impression of being larger. Many
> >animals do the equivalent - like raising fur or having a mane.
> 
> Err, okay.  But remember we are dealing with very huge animals here -- they 
> are already big and weird.  Why mess with them in the first place -- how 
> much bigger and scarier do you need to be?  You can step on or kick a 
> dinosaur which comes close without the rearing, and some sauropods have what 
> appear to be tail "weapons": whiplash in diplodocids, clubs in shunosaurs 
> (unknown/unsure in other Chinese forms).

If a threat display deters a predator(s),then this is a cheap means of
survival. A lot cheaper than incurring wounds.
 
> [...]
> While I will be the first to tell you sauropods have strong hands and limbs, 
> the thought of all the weight crashing back down gives me the willies!  I 

Which would make it effective in defense. (Think of the noise alone!)

> don't care how much cartilage you stuff in there, I don't think the rearing 
> and falling on your enemies thing would work too well.  A more controlled 
> descent, maybe, but then we'd need to look at what muscles and ligaments 
> controlled that descent.

If the pelvic region could support three times the weight, then it seems
overbuilt. And with the center of gravity close to the pelvic region, a
controlled descent is not unimaginable. I think a more pertinent question
to ask is how was the pushoff accomplished.

> [...]