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 > Some comments on recent discussion of T. rex feeding habits:
 > Why have all the comparisons been with modern mammals and
 > birds? Is it taken for granted that dinosaurs had a mammalian
 > type physiology?

No, but the most recent evidence supports it.

This evidence is so new, and so subtle, it is not widely known.

Some time last year a paleontologist did an isotope analysis
(of the sort used to estimate ancient sea temperature from
fossil shells) and determined that, of the 5 or so dinosaurs
he tested, all but one patterned as endotherms.  The *one*
exception was a sauropod - the one group that really is too
large to be endothermic.
 > Large reptiles such as crocodiles, freshwater turtles and
 > monitor lizards are true carnivores, but are also accomplished
 > scavengers, and carrion can be a major component of their
 > natural diet.

So, how is this much different than mammalian predators?
In some areas and seasons, lions eat more carrion then they
do fresh kills.

All you have done is point out that *no* large predator refuses
carrion when it is available.
 > (Incidently, I have also heard that Sue had a healed fracture
 > of a hind leg - can anybody explain how a large biped with
 > mammalian endothermic metabolism could survive long enough
 > without food for such a serious injury to heal?)

Who said she had no food?

Who is making assumptions now?  Modern large endotherms
do manage to survive serious injuries, either by eating
carrion while healing, or by being fed by pack mates.
And there is certainly no reason why T. rex could not have
run in packs - its prey certainly did - there is conclusive
evidence that both hadrosaurs and ceratopsians were herd animals.

swf@elsegundoca.ncr.com         sarima@netcom.com

The peace of God be with you.