RE: Dinosaurs, Size, and Land Area

[Jura <archosaur@reptilis.net>]

Thomas Holtz wrote:

On the other hand, the authors do not take into account the study of Carrano & 
Janis, who suggest that mammals may have a size limit that has nothing to do 
with land area productivity.  Specifically, those authors observed that 
gestation period scales with body size
in placental mammals, so that the largest mammals have multi-year 
gestation periods: a major stress on the individual mothers, and a
very low rate of replacement.
In contrast, dinosaurs (as egg-layers) had egg clutch sizes and rates
of replacement which were essentially mass-independant, and thus
would not face the same constraints to evolving and sustaining 
immense body size.

+++++++++++++++++++++++++

Well that certainly makes more sense. Couldn't quite understand why there would 
be such a huge disparity between ectotherms and endotherms when studies by 
Farlow, Spoitila & Auffenberg all agree that metabolism and food consumption 
for ecto/endos both converge with increasing body size (for vertebrates at 
least). 

Jura



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