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Re: could / did sauropods drink?



Dan Bensen wrote:

>...Small
> animals like gerbils and tortoises can get all of their water from
> vegetables,
> but large, high-metablism animals like sauropods couldn't possibly
> have eaten
> enough vegetable matter to get enough water to fuel their bodies...

Under the assumption that sauropods had as much water in their food as
gerbils and tortoises have, water intake is proportional to food eaten,
which is proportional to food required, which is proportional to
metabolic rate.

Water loss through defecation is proportional to food eaten.  
Water loss through nitrogen excretion is proportional to production of
nitrogenous waste, which is proportional to metabolic rate.  (And this 
loss is minor in uricotelic animals.)
Water loss through ventilation is proportional to oxygen consumption,
which is proportional to metabolic rate.
Water creation and destruction through various chemical reactions is
proportional to metabolic rate.

Evaporation through the skin, mouth, eyes etc. depends on the area of
these surfaces (relatively small in larger animals), and the thickness
of the skin (generally thicker in larger animals), so large animals
have a (probably insignificant) advantage here.

The only advantage I can think of for small animals is their ability to
find shade, avoiding the need to spend water in thermoregulation.  But
that's a different can of worms.

Bill Adlam
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