BATH WATER:
 
Ferret rectal temperatures average between 100 and 103 degrees
Fahrenheit, and I recommended bath water to be measured at 100 degrees F.
The reason I have picked the lower temperature for the bath water is
purely for safety reasons.  First, ferrets being housed in hospital cages
are ill or injured, and many of them are stressed when exposed to water
more than a few degrees (+/-) of the body core.  This is especially true
of temperatures ABOVE body core.  Remember that ferrets are adapted to
cool environments; they can easily raise their body temperature by
increasing metabolism, fluffing their fur, increasing activity, or even
shivering, but since they lack significant numbers of sweat glands on
their body, they tend to overheat.  Even mild overheating can stress an
already ill ferret.  Thus, it is safer to cool them down a bit rather
than heat them up.
 
Second, many kitchen thermometers are only accurate to 3 to 5 degrees of
what is printed on the gauge and/or lack precision to measure the actual
temperature consistently.  Photographic thermometers are generally more
accurate and precise, but they can still be off by 2 to 3 degrees.  Even
medical thermometers can be off at least 1 to 2 degrees, depending on the
quality.  With such a wide range or possible error, it is better to err
so damage is not done.  In the case of exposing a sick ferret to water,
for typical bath times a slightly cooler temperature than that of the
body core will not harm them, but warmer temperatures MIGHT overheat or
burn them, especially ferrets recovering from surgery or those with
diseases that make it hard for them to regulate body temperature.  A
temperature a couple of degrees cooler that of the body core will not
make a big difference in comfort, but it greatly increases safety.
 
Of course, if your thermometer has been calibrated and you know it is
accurate and precise, you can increase the bath water temperature up to
a few degrees warmer than that of the body core; say 105 degrees F as
long as the immersion is brief.  (3 emails)
 
Bob C
 
[Moderator's note: Nope, I don't know what the "(3 emails)" and such at
the end of these posts mean, don't ask ;-)  BIG]
[Posted in FML issue 4416]