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Re: swimming dinosaurs



Bonnie Blackwell writes,

>1.  do ectotherms have much in the way of fat reserves?  if so, what 
>environmental conditions favour fat buildups in ectotherms?

All vertebrates, from fish to mammals, are able to store fat (many lizard use 
their tails as fat recepticals).  It is a relatively simple cellular process to 
convert glucose into glycogen, which can be stored for leaner times.  The 
difference between ectotherm and endotherm fat is in the locations of the fat: 
ectotherm fat tends to be located in specific areas, where endotherm fat tends 
to be located throughout the body.  The "generalized" (my term) fat of 
endotherms is best used for insulatory purposes.  Take a look in any cell 
biology or human physiology textbook for more details.

>2.  would sauropods be able to swim by keeping their tails and necks
>near the water surface (and hence the lungs near the surface) with just
>their heads marginally above water)?  or would they have too much 
>mass below the water surface pulling them downward to be compensated by
>inflated lungs near/at the surface?  if the adults could not swim thus,
>would the juveniles have been able to do so?

I'm going to go out on a limb for this one (and I think I hear it snapping).  
The shape of the lungs tends to be outlined by the rib cage (since the heart 
and lungs are the most vulnerable, and most important, organs in the torso).  
Since sauropod rib cages are pretty massive, then the lungs should have been 
just as massive.  IMO, a full breath of air would provide enough bouyancy to 
allow even the biggest of sauropods to float, and therefore swim, rather well.  
Check out comparative anatomy textbooks (preferably dissection guides) for 
better details

Rob Meyerson
Orphan Vertebrate Paleontologist

***
When the going gets wierd, the wierd turn pro.