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RE: crocs eating hadrosaurs (was Gr. 9 sci proj)



On Sun, 5 Jan 1997, Nathan Myhrvold wrote:
> Large mammalian herbivores like wildebeest, zebra, elk, bison etc.
> typically carry only a single baby per year...

And yet their numbers dominate the large-animal, open-field niches of the
world (similar niches that dinos used to own).

> Bjorn Kuretin, and other mammalian paleontologists have specualted that
> mammalian reproduction is a fundamental limiting factor that has limited
> mammals (particularly terrestrial mammals) to smaller sizes (generally
> speaking) than the upper limits for dinosaurs.

"Limiting" here must be used in a strictly technical sense.  Being big
for dinos may have been a response to ultimately dooming selective
pressures.  Since mammals don't have the same fecundity problems as
dinos (after all, they only have to have one offspring to maintain
populations), they don't have to resort to such ultimately unfit
strategies as gigantism (relatively speaking).