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Re: Mammalian success and egg predation,



>It all started with the speculation that mammals eradicated the dinosaurs 
>by munching all their eggs ( or at least a large enough fraction).
>But then, suddenly, we are discussing why mammals did fill the ecological 
>niches of dinosaurs.
>IMHO, the two facts have not much to do with each other: 
>                   Martin B"aker

Although I wouldn't call the first statement a "fact", I agree with the
notion.  But this leads to an interesting thought:  it is a commonplace that
mammals "supplanted" the dinosaurs, with the popular view that they were
somehow "better".  I doubt that anyone on this list holds to this view; we
all know that though mammals had been around as long as the dinos themselves
they did not really move into dinosaur niches until the dinos themselves
disappeared (though of course this raises the interesting question of why
the dinosaurs did not move into the niches occupied by Mesozoic mammals).

But there is a further way of looking at this - which is to say that the
mammals have STILL not moved into niches occupied by the living dinosaurs -
eg birds.  Bats, numerous and diverse as they are, have not really occupied
anything like the diversity of niches flying birds have (I think this is
because birds have not involved their hind limbs in their flight apparatus,
leaving them free for other uses to a far greater extent than may be
possible for bats).  So in at least one way the mammals have still not taken
over from those dinosaurs that survived (and as far as number of species are
concerned there are more species of dinosaurs around today than of mammals).

The Mesozoic ain't over yet!
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
Home: 1825 Shady Creek Court                  Messages: (416) 368-4661
Mississauga, Ontario, Canada L5L 3W2          Internet: ornstn@inforamp.net
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Toronto, Ontario Canada M5H 3P5