RE: Bipedal apatosaurs and stegosaurs?

[Robert J Meyerson <meyersrt@uwec.edu> (Rob Meyerson)]

Stan Friesen writes;

> > To answer Stan's comment about his rearing gazelle, I concede that
> >  there may be behavioral exeptions at the species level (especially
> >  for the smaller sauropods, where the energy lost by rearing would
> >  be regained a la mode by the food source), but this behavior
> >  wouldn't be common to the group.
>
>Which group?

Diplodicids specifically.  The smaller species might be able to get away
 with a rearing-for-feeding stance, where the loss of efficiency will be
 made up for in the quality of the food source.

>No one that I know of is suggesting that ALL sauropds used a tripodal
>feeding stance.  The suggestion is that *diplodocids* and *dicraeosaurs*
>used this mechanism.

Even among the diplodicids, I have a hard time seeing a herd of the big ones
 all rearing up to feed on the tops of the pines.  The loss of efficiency
 aside, this kind of posture would make these animals more susceptable (sp?)
 to predation.  Imagine a Diplodicus reared up, with it's head in the
 stratosphere.  Along comes a hungry Allosaurus.  Even if the Diplo saw the
 theropod coming, it would take a lot of precious time for the animal to get
 all feet on the ground and to engage it's tail for combat.  During that
 time, the allosaur could easily make an attack and cripple the animal long
 before the Diplo would be in a position to do anything about it.  A
 recipe for extinction, IMHO.

Rob Meyerson
Orphan Vertebrate Paleontologist

***
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