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Re: polar sauropods



John Bois wrote:

<<Dwarfism is not the only response to insular environments. Several
species tend to grow bigger, eg., birds, rodents, shrews. I suppose
one should ask: are dinos more analagous to birds or elephants (which
do become reduced in size) in this respect.

Gautam Majumdar wrote:
 
<<I thought that availability of food would be the primary determinant
between gigantism and  dwarfism in island environments free from
predators. NZ and Madagascar are islands but pretty big with lots of
resources giving rise to gigantism in birds. Dwarfism in elephants
occurred only on small islands with limited resources. Sri Lankan
elephants are not dwarf.>>

  A note on Sri Lankan elephants: they swim, and believe it or not, it
is not that long a swim from Sri Lanka to the Indian mainland.
Elephants have been observed making the crossing. Thus, Sri Lanka (or
elephants, at least) is not an insular environment.

  The pressures/selectivism dealing with gigantism and dwarfism are
comparatively less here than on, say, the Channel Island mammoths,
Madagascar's and New Zealand's super-ratites.

==
Jaime A. Headden

Qilong, the website, at:
http://members.tripod.com/~Qilong/qilong.html
---
All comments and criticisms are welcome!

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