Re: Sauropod ONP...and energetics

[Sim Koning <simkoning@msn.com>]

> From: Guy Leahy <xrciseguy@sbcglobal.net>
>
> One potential problem with rearing up (primarily in
> diplodocoids and Mamenchisaurus)is the extremely large
> heart-head vertical distances might be physiolgically
> constrained by difficulties in producing sufficient
> blood pressure to reach the head, as disussed in the
> article below:

> http://www.journals.royalsoc.ac.uk/media/1lbfddakxn3xwhe1fl1y/contributions/k/b/b/w/kbbwl6ee805dk8vx.pdf

If I remember correctly, I think Robert Bakker made the suggestion that (in 
his words) sauropods were "dumbing down". What Bakker meant was that their 
brains had actually become smaller than their ancestors so that they could 
remain conscious when they reared up on their hind legs. Bakker thinks it's 
so that the brain could still function even during a massive pressure drop 
in the brain. This doesn't explain exactly how sauropods with elevated heads 
such as Brachiosaurs remained conscious though. My guess is that Sauropods 
had some unknown adaptation that allowed blood to make it to the brain 
without having excessive blood pressure. Perhaps the arteries running 
through the neck had a series of small pumps that worked in unison like a 
conveyor belt? Perhaps this is why their brains were so small, maybe such a 
system could only pump a limited amount of blood to the head.

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