Re: Sauropod Energetics (Peristaltic pump)

[dannj@alphalink.com.au]

On Thu, 26 Jan 2006 08:49:54 -0500, Sim Koning wrote
> >Would some sauropods need to maintain blood flow in order to raise their
> >heads long enough to take a mouthful? Surely if a diplodocid (or other
> >species that maintained horizontal necks most of the time) was able to
> >seal off the blood supply out of the neck for a few seconds to prevent
> >blood from draining away from the brain, then a few moments of no blood
> >flow to that tiny brain wouldn't be so critical?
> 
> >It would mean they couldn't raise their heads for any length of time
> >(barring other unknown blood flow mechanisms), but it wouldn't make
> >quick forays into higher elevations entirely impossible.
> 
> That's Bakker's hypothesis, but I don't know how long even a small 
> brain could function without a constant oxygen supply. It would mean 
> that these animals would have to rear up, eat for a few minutes, go 
> back down and repeat. Would this practice burn more calories than 
> what it actually got from the tree? It makes me wonder if this 
> "working out while eating" strategy would be worth it.

If I understand diplodocid anatomy (and I probably don't), their body shape 
and centre of mass would seem to make rearing up relatively effortless. Once 
in a tripodal posture they needn't stay like that to eat (although swallowing 
WOULD be easier in this position than while feeding from ground level). They 
could do what elephants do; reach high, grab whatever looks tempting, tear it 
down, and eat more comfortably from ground level. 

I imagine an animal with several tonnes of mass behind it could tear down 
branches with enough mass so that they could feed from ground level, without 
having to stand on the branch to rip leaves off (which given the length of 
the neck would have been impossible). In this way an animal best adapted for 
low-level feeding could also exploit resources higher up.

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Dann Pigdon
GIS / Archaeologist         http://heretichides.soffiles.com
Melbourne, Australia        http://www.geocities.com/dannsdinosaurs
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