Re: MORE ON SAUROPOD FEEDING HIGH & LOW

[ornstn@inforamp.net (Ronald Orenstein)]

> The only logical
>explanation for the extraordinary length of sauropod necks is to give
>them the ability to reach beyond where short necks could, which is
>only upwards. 

This may be the best explanation, but is it the only one?  One other (which
Michael Crichton even referred to in "The Lost World") is the "cantilever
bridge" model in which the long neck and tail act as counterweights
preventing the inward collapse of the spine.  I have no idea if this notion
has been subject to proper analysis, though.

>        Also, the only other big land herbivores with very long necks,
>giraffes and some extinct ungulates, were or appear to have been high
>browsers. 

However, giraffes are pretty much unlike most sauropods in post-neck
anatomy, with their elongate front legs and sloping back.  Brachiosaurs may
be somewhat giraffe-like, but what about others?

>2 - If diplodocids were mainly low browsers, then they should have
>worn down their teeth with lots of the grit that covers short, near
>ground plants. However, electron scanning study of diplodocid teeth by
>Fiorillo found that diplodocid teeth show little wear from grit, less
>than that seen in shorter necked camarasaurs. This suggests
>diplodocids fed mainly in the crowns of trees.

However, it would also be compatible with browsing on soft aquatic
vegetation (which a long neck might help reach from shore).  Elephants in
old age often concentrate on browse of this sort, when their teeth are no
longer capable of dealing with tougher stuff - the two ideas are not
mutually exclusive.

--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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