> Mick... I'd guess that the main reasons for the lack of "large critters" these
> days is evolutionary common sense. That is, it's very hard to feed such a
> large body. Easy to die off if food supplies are decreased even a small amount
> due to weather, etc...
The current ice age might be a strong reason why the large creatures
are rare; the climate has varied a lot the last few million years, and
stable periods suddenly end (like when the current interglacial
began). A stable climate and environment favors specialization, and it
is possible to maximize one's food intake by specializing, giving the
resources to grow to a large size (which is advantageous in terms of
predator protection and most likely in other ways).
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