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<<> Big flightless birds evolved in
australiaand other isolated(big or small)
> enviroments because of the absence of big > predators..you know how the story ended. Hah! Big flightless birds evolved in Australia: Dromornithidae have just turned out to be carnivores! Big flightless birds evolved in Laurasia: Gastornithidae ("Diatrymidae") have been confirmed to be carnivores! And phorusracids... All these were the big predators themselves!>> so...?
I said that they evolved because there were non big
predators(this is probaly not true, but it's not important for what
i'm saying), not they couldn't have become the ruling predators
themselves..
Were the flightless birds that evolved in
areas where big mammalian predators were present, all carnivorous?
what about non-carnivorous(whatever this means in
the single cases) flightless birds having evolved in
hunter-poor areas and carnivorous birds in more competitive ones(from
the point of view of predation)???(I'm not proposing this, I'd only like to know
if its true or not, since I think it's already known)
<<Carnivorous mammals were around in all
these areas all the time. They just
didn't grow larger>> Do you consider it(or anybody else with more
knowledge than me) as being the consequence of the presence( competition by) of
big predatory birds or the same reason for which these birds could evolve?..i
think it would be hardly possible to know, but i ask....
<<I don't know much myself. I just can tell
that for much of the Neogene
ostriches were present in all European and Asian steppes>> Ok, thanks for the info, but I'd rather focus on
their origin more than their presence in some zones.
..However the fact that their remains come from
deposits covering a long period of time, likely means that they got exitint
after a long permanence( and perhaps not even because of predatory
pressure) in these areas, so their success could have been less
related to the absence of mammalian predators than
suggested....
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