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Re: (arthritic) Sauropods vs. Gravity - all



[ held back by another address problem -- MPR ]
------------ start of forwarded message:

From: Michael Bruce Habib <mbh3q@m.mail.virginia.edu>
To: dinosaur@usc.edu
Subject: Re: (arthritic) Sauropods vs. Gravity - all
Date: Tue, 05 Mar 2002 20:48:10 +0000

> A quick search for facts on the web shows that the gestation period
> of large whales is actually about *half* that of elephants (about a
> year as opposed to nearly 2 years for the elephants). Exactly how
> strong is the relationship between size and gestation period? Are
> whales exempt from the usual rules somehow? (By being aquatic? How
> would that matter?)

The relationship between size and gestation period is, as 
far as I know, very strong within groups/lineages.  
However, because other factors chip in, you have to be 
careful about comparing across different groups (like 
whales versus elephants).  Bascially the same problem of 
independence that we all know and love.  At the moment, 
whales seem to clade with artiodactyls, so perhaps a 
comparison there would show an aquatic vs terrestrial 
difference in gestation times.  It may also be true (and 
this is really going out on a limb for me, because I don't 
know whale reproduction very well) that whale young are 
smaller at birth compared to their mother than in 
elephants.  (More mother per unit of baby can lead to 
faster young output).

--Mike Habib
habib@virginia.edu