By now you should realize the death rate in polecats has nothing to do
with diet, except when they don't eat enough.  Knowing this, you can
now ask, What is the proof the diet polecats consume in the wild is the
best-possible diet?  Virtually EVERY study of diet, be it in animals or
humans, show the diet the species evolved eating is physiologically the
best one for them.  No one would suggest the wild diets of koalas,
anteaters, bats, or shrews are not optimal for their health, and the
same is true of polecats.
 
Every aspect of the ferret's anatomy deals with hunting animal prey.  The
short legs and long neck to go down burrows and to carry out prey without
stumbling over it, or getting stuck in burrows.  Their ears being able to
hear low and high frequencies, so they can hear prey outside and inside
burrows.  Their sense of smell that acts like a flashlight to illuminate
prey in lightless burrows where vision is no help.  Their teeth are the
teeth of a hypercarnivore, designed to kill in the front and render in
the back; even the ferret molars are designed to crack bones and insect
carapaces rather than grinding food.  The jaw of the ferret locks into
place to increase bite strength and cutting ability.  Ferrets have a
simple stomach, hardly nothing more than a sack to hold food until the
acids break them apart, with a very acidic stomach pH.  A pancreas
adapted for a low carbohydrate diet.  A bowel adapted to a flesh diet,
having an extremely fast transit time, a lack of an appendix and caecum,
and only a microscopic division between the small and large intestines.
A need for essential fatty and amino acids, used for growth, development,
and maintenance that in nature are only found in animal carcasses.  Baby
teeth coming in so kits can eat meat before the eyes and ears open.
When you look at the body of a polecat, or their domesticated cousins
that inherited the traits, you are looking at a work of art, designed
for a single purpose: to hunt down, kill, and consume animal prey.  It
is beautifully designed; a tribute to carnivory.  All those adaptations,
in body shape, in brain development, in metabolism and physiology, took
place over millions and millions of years.  The optimal diet for these
animals is the one they were designed to live on: prey animals.
 
As for the other question, do older ferrets have different nutritional
requirements, and the answer is yes, no, and no one knows.  As a ferret
ages, they slow down so the caloric requirements drop, but no one knows
by how much.  Most ferrets are quite active, even when old, so the drop
may not be as much as seen in other species.  Besides, ferrets tend to
eat to meet caloric needs, so they may actually require a food that has
more nutrients and fewer calories to make sure they meet nutritional
needs.  There is some concern about protein levels in older ferrets,
mostly voiced by those who insist on extrapolating ferret requirements
from dogs.  Ferrets have a metabolic pathway that can utilize protein
to make energy without risking an acidic shift in blood chemistry.  It
appears this pathway MAY be responsible for the protein tolerance seen
in older ferrets compared to other species.  One thing is for sure;
except when the ferret is suffering from a specific disease, there is
no evidence that suggests a diet containing protein and fat in amounts
comparable to wild prey will harm a ferret.  In contrast, the evidence
that elevated carbohydrate levels is unhealthy for a ferret is well
supported.  If there is no carbohydrate requirement in an animal, there
is usually a reason why.
 
More questions answered tomorrow.
 
Bob C
Communication?  [log in to unmask]
Questions?  [log in to unmask]
[Posted in FML issue 4575]