I was slowly putting the finishing slanderous accusations in the last parts
of the pet food label series, and gave the lot of them to a good friend and
fellow critical thinker for comment.  I am glad I did, for two reasons.
One, in my drug induced state, I made a serious factual mistake by failing
to insert an "im" in front of a word (but I won't tell you which word), and
two, it was pointed out to me that I was assuming people understood basic
comparative nutrition.  It was suggested that I discuss a tiny bit of the
philosophy *I* use, since it is that background I draw upon to write these
posts.
 
1. Animals evolved eating specific foods, which over long periods of time
resulted in morphological and physiological changes which better adapt
them to that diet.  In ferrets, there have been changes in the dentition,
gastrointestinal tract, digestive enzymes, and metabolic pathways which
reflect the fact.  Ferrets are obligate (or strict, or primary) carnivores.
An obligate carnivore is not just an animal which eats 95% or more of
animal food, BUT is also REQUIRED to eat animal food because they cannot
get essential nutrients from plants.  A ferret CANNOT be a vegan.  There
are at least two amino acids (maybe three) that have been proven to be
essential in ferrets, and neither are manufactured by plants.  The ferret
lacks ANY type of a caecum, and there is not even a (macro) visual
difference between the small and large intestines.  Digestion time is
extremely fast (the intestinal transit time is 3-5 hr.) which makes plant
digestion difficult or impossible.  Also, the ferret lacks many enzymes
required to digest plant food.  The ferret's teeth are heavily modified to
render meat into gulpable pieces; they do have a molar, but it is extremely
small--in the lower jaw it is about the size of the flat end of a straight
pin.  ALL these modifications (and more) are proof of the extreme dietary
modifications bred into ferrets (via polecats) over millions of
generations.
 
2. When the adaptations to diet have reached stasis (that is, there are no
external factors pressuring change), then the diet consumed by the animal
is the best diet possible.  The polecat-weasel family is very stable; which
new species erupt and old ones go extinct, the basic size and shape of the
group has remained extremely stable for about 10-20 million years.  While a
scientist cannot reach into a bag and pull out a 10 million year old
weasel, we can assume the diets of the ancestors were about the same as
their modern offspring.  How?  Since body and tooth shape is strongly
influenced by hunting pressure, and no significant changes have occurred
in either, we can conclude that while there may have been changes in the
species eaten, the TYPES of animals have remained consistent.  This
suggests ferrets (via polecats, via weasels, via protoweasels, via general
mustelid ancestor) have evolved dietary modifications over a long time
period, and those changes have become integral to the health of the ferret.
 
3. Domestication is a short term, human mediated process.  An animal can
be technically domesticated within 7 generations, give or take a few,
with VERY few external and NO internal changes.  Domestication results in
changes which benefit HUMAN desires, so those traits which are most
impacted are generally those of behavior (more friendly towards humans
and/or cohorts), muscle yields (or egg or milk), health, reproduction, and
fur quality.  Domestication works best on those traits which are inherently
adaptable; that is, which have a wide range of values.  It works poorly on
those traits which have little or minute variation.  In other words, in the
ferret, domestication can change behavior rapidly, because behavior is
highly variable.  Mammalian physiology, while certainly having variation,
does not have such a wide degree of latitude because physiological
processes are governed by biochemical laws.  Physiological functions are
therefore the hardest to change, and there is NO evidence they have changed
since ferrets have been domesticated.
 
4. It is a reasonable assumption to conclude the ferret's optimal diet
would be close to what they evolved eating; that is, small rodents,
amphibians, rabbits, small birds, carrion, worms, insects and the rare
fruit.  Any diet which is structurally similar in terms of nutrients, bulk,
energy density, and components of elimination SHOULD result in optimal
results.  In other words, to eliminate the effect of diet on the health and
condition of the ferret, they should fed a diet as close as possible to the
evolutionary diet, in amounts which eliminate limiting factors.
 
5. Pet food is NOT necessarily the same as an evolutionary diet.  It is a
dietary substitute which approximates the nutritional requirements of the
ferret, which are, at this point, unproved.  Since there are no published
reports of the ferret's nutritional needs, BY DEFINITION, it is not PROVED
that a commercial food can adequately replace the evolutionary diet, and
claims of such must be viewed with skepticism, especially with the
introduction of food classes not typically consumed.  In other words, it
is up to the pet food people to PROVE carbohydrates are benign, and us to
question.
 
Bob C and 16 Mo' Theoretical Mustelid
[Posted in FML issue 3052]