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Re: Blood flow in Sauropods



>From GSP1954@aol.com Tue Sep 12 21:43:56 1995
 > The energy cost of moving a giant body a few steps to stand next to a plant
 > is minimal (I have done the calculations), growing a long neck is much more
 > difficult.
 > 
An *moving* a long beam is, at best, clumsy. Overall, this just doesn't
seem to me to be a likely basis for such *extremely* long necks. Even
brachiosaurids have necks that woul make a giraffe proud, and diplodocid
and euhelopid necks are just plain awesome. (We have a Mamenchisaurus
mounted at the LA Natural History Museum - you could park a several
buses under the neck).

When you look at the heights accessible, the advantage becomes obvious,
NOTHING else at that time was browsing at that height as we have no
fossils of arboreal bulk herbivores comparible to colobus monkeys from
the Mesozoic.  Even if bird ancestors were arboreal, they were almost
certainly insectivorous or frugivorous, not bulk herbivores.

Accessing a unique resource is a *powerful* selective force - one
of the strongest (other than sexual selection). This is thus quite
sufficient to offset the cost of growing and maintaining such a
huge neck.

In combination with bodies obviously adapted to bulk feeding (unlike,
say, ostriches, which concentrate on select high energy foods), the
conclusion is pretty much inescapable that sauropods were high browsers.

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.