As another, perhaps more topical example, 14 different people have asked
me in the last three weeks if I was worried about the risks of ferrets
developing protein-based stones from a high protein diet.  My answer is
no, no, no, no, absolutely no, I am not, never!!  Ferrets are obligate,
primary carnivores with unconditionally, unquestionably, categorically,
and absolutely zero requirements for carbohydrate, which is a good thing
because in nature they consume a diet between 40% and 60% protein,
depending on the percentage of fat.  In a very real sense, ferrets have
been "genetically engineered," via natural selection, to consume a high
protein diet.  Ferrets couldn't survive as a predator if they developed
stones from high protein diets, and if anyone suggests such a diet could
cause stones in a normal, average ferret, demand scientific proof.  This
doesn't mean it can't or doesn't happen, but when it does, it means the
individuals would normally die, and the bad genes exit the breeding pool.
The process is called, "natural selection," and it has regulated the
evolution of the weasel group of carnivores for millions of years, and
in a seasonally breeding animal like the ferret, that means millions of
generations.  We know for a statistical fact that if this is indeed a
problem in a small number of ferrets, it CANNOT be a trait in the general
genetic pool!  Why?  Because Mendel has taught us that it would present
in predictable ratios that are substantially better than the 1 or
2-million-to-1 chance of having the problem if ALL real, probable,
possible, and imagined cases are proved to be correct.  Think about it
for a moment.  There might be 5 million ferrets in the Western
Hemisphere, and perhaps as many in the Eastern Hemisphere.  How many
ferrets have this problem?  Even if there are only 1 million ferrets on
the planet, the ratio would still be so skewed that the trait could not
possibly be a genetic trait in the general population, and if anyone
suggests it is, the burden of proof is on them to demonstrate otherwise.
If this problem exists and is not actually lab error (there are more of
those than you can ever imagine), it is usually either a spontaneous
mutation, caused by something else in the diet or environment, or a
defect in a particular breeding line, usually associated with inbreeding.
 
One more comment is in order--a bit off the topic, but relating to the
essential genetic character of the ferret (and to ward-off follow-up
questions).  Ferrets are domesticated polecats, and polecats are nothing
more than a group of weasels that are larger than the rest.  These
animals eat different sizes of prey, but they all eat animals of one
type or another to such an extent that it is nearly a universal fact that
they exist on a diet that is 95% animal based, or greater.  Less than 5%
of the diet is non-animal, which includes fruits, nuts, prey digestive
tract materials, and honey.  There are more than 1000 scientific papers
published in the last 150 years that detail the diet of this group of
mustelids--including more than a dozen for the New Zealand feral ferret
alone!  I know; I have them in my files.  The literature documenting the
diet of this group of animals is so uniform and so extensive that ANY
suggestion that any member of the weasel group requires a different diet
places the BURDEN OF PROOF ON THE PERSON SUGGESTING THE DIFFERENCE!  The
burden of proof isn't on the people who suggest a natural diet is good;
we already KNOW it is good because weasels scarfed it down for millions
of years and they are still here, thriving, healthy, reproducing, and
in some cases, expanding their range.  Nor is there a requirement of the
natural-food group to run scientific tests to prove their diet is a
better one; natural selection has run experiments on that diet for
several millions of years.  We KNOW that diet works, so if anyone,
especially someone with a vested interest in a pet food company, suggests
some other diet is better, THEY have the burden of proof to show their
claims are reliable.  This means the natural diet is the STANDARD by
which all other diets are judged, like it or not.  Put simply, I dont
have to prove the natural diet is good because weasels and polecats
have lived successfully on it for millions of years, which means it
has already proved it's nutritive value.  Nor do I have to prove it is
better than any other diet because, again, the burden of proof is the
responsibility of the people who claim their diet is equal to or better
than the one the ferrets evolved consuming.  If the people making such
claims don't understand they have the burden of proof, then I worry about
the adequacy of their scientific methodology and if it hasn't biased
their results or conclusions.  This is an extremely important point,
because there is a preponderance of evidence that a natural diet is
better for animals of any species.  The evidence is so overwhelming that
it cannot be dismissed; if you want to claim something is better, or
even it's equal, then you have to prove it.  And I mean real, scientific
proof, not commercial claims built on truncated, brief tests, but rather
scientifically designed tests performed by an impartial committee that
uses approved scientific methodology, and who will publish their
findings.
 
The bottom line about inbreeding for a desired trait is that
statistically it generally results in the introduction of undesired
traits simply because of the number and complexity of the remainder of
the genome.  If a bad or mutated gene is near the genes that code for
your favored trait, it can link to it in a manner that you can't predict,
and inbreeding will not just set the desired trait, but the bad ones as
well.  If you don't believe it, just check out the books on cat and dog
genetic diseases.  Ferrets, in contrast, have very few.
 
On the other hand, each and every hamster you see in the pet shops
around the world had their beginning in 1930 with a male and two females
surviving from a single adult female and litter of 8 removed from the
wild.  There must have been a substantial amount of inbreeding necessary
to produce the millions of hamsters that run through little plastic
tunnels today, so it can be done.  I don't know enough about hamsters and
their genetic problems to feel comfortable about posting about them, so
perhaps someone with more knowledge in the manner can respond in more
detail.  At a superficial level, it appears inbreeding hasn't caused
really significant problems in hamsters, but I admit I could be mistaken,
and if so, I hope the statement is corrected.  Nonetheless, even if true,
my opinion is that the risks of problems from inbreeding vastly outweigh
the advantages, so I don't recommend it.
 
Bob C  [log in to unmask]
 
It was the White Rabbit, trotting slowly back again, and looking
anxiously about as it went, as if it had lost something; and she heard
it muttering to itself, "The Duchess!  The Duchess!  Oh my dear paws!
Oh my fur and whiskers!  She'll get me executed, as sure as ferrets are
ferrets!  Where can I have dropped them, I wonder?"
--Lewis Carroll 1866 Alice's Adventures in Wonderland.
[Posted in FML issue 4786]