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Re: Blood flow in Sauropods



>I have to disagree.  *All* living animals with similar long necks
>are *high* browsers.  They normall browse at the vertical limit
>of their reach.  The similarity of sauropodomorph necks to those
>of living giraffes, camels, llamas and such like is too close to
>be mere coincidence.  This is clear evidence that they were high
>browsers. Even the less extreme neck of the gerenuk is apparently
>an adaptation for high browsing.
>
>The simple fact is that a long neck is a "maintenance" and
>development problem and merely establishing a long reach is
>an insufficient advantage to overcome these problems. [Even
>when horizaontal such a long neck requires special muscles
>and tendons to support it, and costs more energy to hold in
>place than a normal neck].
>

A fair arguement but not one as decisive as you would indicate. Analogy to
modern animals may be constructive but can not be construed as "clear
evidence" for analogous structures in extinct animals. I suspect that many
of the problems we have in interpreting the behaviour and functions of
extinct animals is greatly complicated by trying to make them behave and
function like modern animals.

A previous rebuttal post to my initial post can not see why a long neck
acting horizontally provides any special benefit ans compared it to
operating a lawn mower on a long pole. This is an ad absurdium argument.
Clearly a long, mobile neck can increase the range of available browse
without moving the body of the animal, whether that range be horizontal or
vertical. As to the above argument against horizontal browsing based on
energetics, we clearly know very little about dinosaur energetics and so
this arguement relys of too many assumptions. It is quite feasable that an
unknown difference in the metabolic capacities of sauropods and mammals
makes long neckked, horizontal browsers unviable in mammals but quite OK
for sauropods.

Cheers, Paul

pwillis@ozemail.com.au