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Re: Ratites and egg predation: the pattern confirmed.



        If it is really such a battle of differential reproductive 
success, we ought to see something similar occuring among the placentals, 
marsupials and monotremes. We don't.
         One could perhaps argue that a superior reproductive strategy
allowed placentals to flourish. But if you look at the pattern, what
we see is that placentals and marsupials coexist for long periods of
time- millions of years- and that it is remarkably uneven- in
Australia and South America for example, marsupials flourish in the
face of placental competition for tens of millions of
years. Monotremes have held out a long time, multis (which were
probably either egg-layers or marsupial in their birth habits) held
out for millions of years against the rodents. The virginia opossum
and kangaroos continue to show that it's more than just reproductive
strategy that make you a success.
        Now take a look at the dinosaur extinction. Non-avian
dinosaurs go completely extinct the world over in a brief span of
time. Unlike with marsupials and monotremes, there are no island
continents where dinosaurs hold out. The pattern appears to be the
same the world over, unlike the extremely uneven pattern seen in
placental/marsupial competition.
 The pattern is completely at odds with the long term type of
competition you see when one group edges out another.
        Mammals did not edge dinosaurs out. You can see this because
it is only AFTER the dinosaurs went extinct that mammals begin to
radiate into the niches dinosaurs formerly occupied. After the K/T
large herbivores and predators emerge, not before- the reverse of what
your hypothesis would imply.
        And the South American extinctions ?  Plenty of placentals-
ground sloths, glyptodonts, south american ungulates, etc. - also went
extinct.