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Re: Predators of the non-stealthy egg theory.

three things.......

> Mammals were small and vulnerable to open-
> field attack.  While there were dinosaurs around there could be
> no mammals.  While they lived, the dinosaurs (like crocodiles in
> the semi-aquatic environment) were niche sovereigns.  

What about the niches where they were likely direct competitors such
as egg-eating.  We KNOW dinosaurs ate dinosaur eggs (or we did for
quite some time, but now we are a bit confused about such things as
Oviraptor.)  We BELIEVE mammals ate dinosaur eggs.  Isn't this direct
competition?  The same niche?  Is your arguement for your position or
against it?
 (It was probably a competition that lasted as long as mammals and
dinosaurs existing together (what, 120 million years?) so would you
say the extinction was a result of egg-predation over a very long
period, or was it perhaps something a little more specific to the 60
million-years-ago mark?)

>      But there _is_ much evidence of change, especially in
> mammals.  Cognitive development is quantifiable (cranial
> capacity).  This newly evolved "technology" could allow the
> mammal to learn new predatory tactics.  For example, they could
> now imagine a group of eggs which were out of site, under a pile
> of leaves (incidentally, my 7 yr old daughter's science project
> involves egg-predation and crows.  She, is piling wood chips and
> leaves on top of an egg which she puts out each day.  Today the
> crows rummaged through a one foot pile to reach the egg. 

Your 7 yr old has evolved 60 million years further than the state of
mammals at the extinction of the dinosaurs.  So have the crows.
Perhaps the "technology" of cognitive thought is a little newer than,
say, the Late Cretaceous.  Where is the evidence to support or deny
this?  I'd like to see a fossilized thought, please.;]

> Mammal egg layers could be stealthy.  They could put them in
> burrows.  Look at the platypus.  It burrows _under water_.  Tell
> me that is not an adaptation for stealth--against egg predation!

 Underwater burrows would still allow access for snakes and crocs, I
don't see how water-oriented burrows would actually be all that much
better for the platypus than a ordinary burrow, nor where cognitive
thought guided the platypus in choosing the same sort of burrow as,
say, a burrowing owl would. (As I understand it, platypuses are dumb
as bricks) The platypus is laying it's eggs on a landmass which is
known for it's impressive fossil record of really really big snakes.

-Betty Cunningham