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Re: Sauropod ONP...and energetics



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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