Q: "Out of eleven ferrets, six of them (55%) have or had serious medical
issues while four of them (36%) have died from those issues.  Out of four
dogs and two cats, for example, we've had only ONE animal die from a
medical condition.  That's a 16% mortality rate.... So the underlying
question to all of this is: Why are ferrets so darned sickly animals?"
 
A: Well, first, all animals have a 100% mortality rate, at least
sooner or later.  And if they didn't die from "unnatural causes" (car,
poisoning, shotgun), then they DID die from a medical reason.  Even if
an animal dies quietly while sleeping, THAT is evidence of a serious
medical problem that ultimately killed it!  Perhaps it was an undiagnosed
bleeding ulcer, cardiac or vascular disease, liver or kidney disease,
long-term chronic infection, or dozens of other medical reasons.  If you
had a necropsy done on EVERY animal, it would have shown ALL died from
some type of medical condition.
 
I suspect you are observing multiple phenomena.  First, much of the
disease seen in ferrets are an epiphenomenona of aging and are not
really correlated with ANY genetic fault.  For example, ALL older
animals get cancers regardless of species (each species tends to have
a predisposition towards certain types of cancers, but they still get
them).  Second, in some species, medical problems are more visual than
in others, so tend to have a higher frequency of veterinary treatment.
Third, I think there is a general misunderstanding about how long ferrets
are supposed to live when compared to dogs or cats.  Fourth, because
ferret lives are compressed into fewer years, their medical problems are
compressed into fewer years as well.  Last, averaged statistics are fine,
but there are always random individuals that are statistical outliers
(sort of a scientific way of saying you've had bad luck).
 
Did you know the national averaged lifespan of a pet dog in the United
States is just 10-12 years of age?  Irish Wolfhounds only live about 6-7
years, Great Danes about 7-10 years, and Jack Russell Terriers live about
13-15 years.  Non-breed, mongrel dogs live about 12-16 years.  The upper
limit for dogs is roughly 20 years of age, although rare individuals live
longer.  The American cat lifespan is reported to range between 8-19
years, with the average death about 10-14 years and an upper limit about
18-22 years.  Many fancy breeds of cats only live 7-10 years, and some
less.  American ferrets typically live about 5-8 years, with 10-year-old
ferrets being uncommon, and anything older quite rare.  A few ferrets
have been reported to live to 12 or 13 years, with 14 years of age
apparently the upper limit.  Extremely rare individuals from all three
species have lived longer--the equivalent of a human living in a decade
or more past 100 (they won the longevity lottery, with one chance in the
millions).  You didn't say how old your ferrets were, but I would guess
most died in the 6.5 +/- 1.5 years range--an average life span.
 
Animals have to die from something, and older animals die from cancers,
various organ dysfunctions, deterioration of the immune system, and
general senescence.  Some of these problems are extremely visual; a
ferret with cardiomyopathy might have ascites (fluid build-up in the
abdominal area), but a dog with cardiovascular disease may not show
ANY danger signals until they die in their sleep.  In this example, one
would get a vet bill, and the other would not, but it doesn't mean the
later didn't die of a medical problem.
 
[Part 2]
Assume dogs and cats live about 12-14 years, and ferrets live 6-7 years.
Assume all have an average of three medical problems during their
lifespan.  Finally, assume medical problems tend occur in the later life
stages, roughly the second half of the life span.  That would mean the
three medical problems in the ferret would occur in the last 3 or 4 years
of life, roughly one medical problem per year.  In the dog and cat,
medical problems would be a couple of years apart.  Many people interpret
this time-compressed view of medical problems as "proof" ferrets are
sickly when it is simply an epiphenomenon of a shorter lifespan.  I've
studied this phenomenon extensively so I can factor it into a general
economic model of domestication that I a working on, and if you looked
carefully at the veterinary literature, cats and dogs suffer a WIDER
range of medical problems when compared to ferrets.  Part of this is
because ferrets have only recently been scrutinized at the "cat-dog level
of veterinary medicine," but part is also because ferrets simply suffer
from a narrower range of medical problems.  I believe a large part of
this difference is related to inbreeding.  Ferrets may display a wide
range of fur coloration, but anatomically they are pretty much "mongrels"
and do not display the serious and life-shortening medical problems of
most fancy breeds of dogs and cats.  Sadly, some breeders seem determined
to change that.
 
There isn't time or space to discuss the causes of cancer in this post,
and I'm not going to differentiate between a neoplasm, carcinoma, or
any other term except to say not all tumors are neoplasms, and not all
neoplasms are cancers.  Those tumors present in the pancreas responsible
for insulinoma are probably due to a combination of genetics (the
evolutionary history of dietary adaptation) and environment (consumed
diet), rather than damage to multiple genes as seen in cancer.  Both
are significantly correlated to environmental factors, which means they
are also correlated to the age of the animal.  The reason the two are
correlated is because the older you are, the more you have been exposed
to those types of environmental agents that cause genetic damage and
physiological changes.  The bottom line is, older animals (dogs, cats,
ferrets) display more abnormal growths than younger animals because
they have been exposed to more harmful environmental agents.  Not all
environmental agents are from outside the body; one of the hypotheses
explaining longer lifespan in mammals undergoing caloric restriction is a
lowered exposure to free radicals and other substances generated during
digestion and metabolism.
 
To illustrate the effect of diet and environment on ferrets, consider
the following.  Ferrets have been shown to be extremely sensitive to
second-hand smoke, probably in part due to their small lung size, rapid
respirations, and constant testing of the air for odors; they are furry
little air filters.  Recent studies have shown ferrets receiving
supplementary doses of beta-carotenes are at a significantly HIGHER risk
of disease from second-hand cigarette smoke than those that don't get
the provitamin.  Somehow, for some reason, beta-carotene exacerbates the
effect of secondhand smoke on ferrets, showing diet can have a direct
influence on other environmental factors.
 
Finally, you just may be unlucky the pet-owner equivalent of someone who
always craps out playing dice.  Toss a completely balanced coin in the
air a couple of thousand times, and 50% of the landings will be heads.
Still, within that series of tosses will be runs of numerous heads or
tails in a row--hardly 50%.  Disease is the same way; the "sickly
ferrets" experienced by an individual become, at the population level,
nothing more than the equivalent of a run of heads when flipping a coin.
Simply put, it may be nothing more than coincidence (random chance) that
you have had such bad luck.
 
I am very sorry for your problems, and I hope your ferrets do better in
the future.
 
Bob C
[Posted in FML issue 4131]