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Re: Theories on the extinction of dinosaurs

>> Stress.
Heinrich Erben of Bonn university's institute of Palaeontology did some
research in the early 70's into
thousands of eggshell fragments from the upper maastrichtian of the
french pyrenees.  His studies
showed that eggshells in the older layers had eggshells around 2.5mm
thick.  The younger, more recent
layers produced shell fragments a mere 1mm thick - too thin to provide
enough calcium to the bones of
the developing embryo within.  The thinning of the eggshell is a
sure-fire sign of stress.  Seagulls in
crowded colonies lay thinner eggshells than ones not subject to mass
territoriality and food supply
issues.  The previous 3 events, especially the top two, are known to
have occured and all the animals at
that time would have been subjected to the same conditions.  Perhaps it
was their way of dealing with
those conditions that decided who would survive and who wouldn't.<<

If a meteor impact doesn't produce stress, I'll eat my keybord.  :)