Re: Triceratops defence

[Ronald Orenstein <ornstn@home.com>]

At 11:47 AM 13/06/1999 -0400, John Bois wrote:
>The best analogies we have, ratites, suggest that parental guarding was
>essential.

I would agree that it is quite likely - though megapodes don't guard their
young, of course.  But to follow my point - if you wanted to depict this
activity how would you do it?  Who does the guarding - males?  females?
both? a group?  Do the young form creches?  Do they stay in a nest?  All
these things could have happened - but we will probably never know the
details.  That's why a question about how dinosaurs defended their nests
is, really, pretty much unanswerable (the brooding oviraptor aside, I suppose).

>My point, though is that we _can_
>apply our skills of reason to hypotheses for which there is only
>circumstantial evidence, in order to get closer (at least) to the truth.

Certainly - though this is a lot easier to do for things like red blood and
other physical features that are shared almost certainly basal to the clade
including dinosaurs and are found in living birds.  For details of
behaviour, it's quite another matter - though both crocodilians and birds
show parental guarding, for instance.

However,
>it is highly likely, assuming they laid eggs, that triceratops laid their
>eggs in a nest and defended it vigorously. 

Not all known dinosaur eggs were laid in nests.  Perhaps it was as you say
- or perhaps the eggs were carefully hidden somewhere - we don't know -
possibly with different parts of the clutch in separate places.  Until
someone finds fossil evidence we are only assuming.  Of course there is the
(perhaps remote) possibility that they gave birth to live young that were
active soon after birth, like zebras or elephants today - if this was the
case it could have been a useful adaptation for the animals if they were
continuously on the move.  Again, we just don't know. 
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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