Re: T.rex

[Stan Friesen <swf@tdat.ElSegundoCA.NCR.COM>]

tonyc@foe.co.uk writes:
 >
 > >  > 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.
 >
 > You're quite right, I have overlooked this isotope data -
 > could you post a reference for this?

Ack, no I'm afraid not.  I ran across it in Science News
last year sometime.  I suspect it was published in either
Science or Nature, but I am not sure.
 > >
 > > All you have done is point out that *no* large predator refuses
 > > carrion when it is available.
 > >  >
 > Which is exactly my point - when the whole data set (large
 terrestrial
 > predators) is examined, the conclusion that T.rex was a predator
 > with possible additional scavenging is strengthened.  It is surely
 > still appropriate to consider all available data rather than a
 subset.

True.  My approach is simply to assume that any predator will take
carrion unless proven otherwise.

 > >
 > > 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.
 > Yes, I agree many, possibly most, dinosaurs were certainly social
 > herd animals.  However, my point about the relative absence of
 > carrion still stands - T. rex and relatives must have swallowed
 > food in large chunks, not picked at carcasses.

Well, who, other than another T. rex, is going to challenge a
a T. rex for carrion?  Even an injured animal like "Sue" could
have preempted a carcass from anything less than another T. rex.

So, in years in which carcasses are plentiful for some reason,
an injured endother could survive adequately, if poorly, on carrion
alone.  [Now, in "carcass lean" years, things would be different].

 > I find it very hard
 > to accept social feeding of an injured conspecific in T.rex or any
 > other reptile.

Part of the point is that dinosaurs seem to have been socially
more like birds than like reptiles.  Instead of imagining T. rex
as a reptile, imagine it as a great big flightless bird.  Is it
really that hard to see social sharing now?

Of course, there is no real evidence of social interaction in
T. rex as of yet, but it is closely related to forms with known
social interactions - living birds.  (Depending on which cladistic
analysis you trust the most, T. rex may be very close indeed to
the ancestry of birds - if the tyrannosaurids are the sister group
of the dromaeosaurids *and* birds are closer to dromaeosaurids than
to troodontids, as suggested in one article in the most Oct/Nov 1993
issue of the Canadian Journal of Earth Science).

 > It does seem clear that some very interesting data is being denied
 > us, and may even be destroyed, by the arguments over this fossil.

Quite.  The FBI really had no business siezing the fossil until
*after* judgement had been reached.  After all, it is not as if
such a large dingus could be moved without it being seen, so
a court order constraining the Black Hills Institute not to sell
or transfer the specimen combined with surveillance would have
been quite sufficient.

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

The peace of God be with you.