As many of you know, for the last half-dozen years or so I ve been
working on an analysis of domesticated ferret, feral New Zealand ferret,
black-footed ferret, and wild European and steppe polecat skeletons.
As part of that analysis, I ve spent years traveling to American and
Canadian museums and universities to collect data.  I will be poking
around in European museums this fall and hopefully I ll be traveling
to New Zealand by next spring for the same purposes.  Besides data
collected from museums, I have also been accepting the donations of
deceased ferrets from various sources, mostly interested veterinarians
and sympathetic shelters, but from private sources as well (although
no longer).
 
These sources were carefully selected (and the donations screened) to
result in a random population , very important in statistical analysis.
This is a VERY long-term study because it takes an extended time to build
a population of skeletons that can pass the statistical tests that allow
them to be accepted as representative of the ferret population as a
whole.  If this isn't done, the data has no real predictive value.  The
data I have collected so far has been carefully conserved to prevent
it from entering public domain so when the study is completed, it will
remain publishable in the scientific media.  Outside myself, only 4
people have ever seen the data (but not the complete analysis), and each
expert has only seen the part they are concerned with (dental pathology,
sexual dimorphism, genetics, and domestication).
 
As I enter the results, I do not look at it in any great detail so
observations don't subconsciously influence data collection.  I use a
double-blind method where the sex, age, neutering, fur coloration, cause
of death, source and identity, and other factors of the individual ferret
are hidden so bias does not influence measurements or interpretations.
Individuals are given random number identifiers, and data collected from
individuals are given a second random number identifier.  In other words,
the ferret Bob C is given a number to hide its identity, No. 7364926.
After cleaning and drying, skeleton 7364926 is then measured, but the
data are recorded under a second number, No. 040326-01.  While the
double-blind method makes it difficult for me to assign the results of a
single set of measurements to a specific individual, I can see X% albinos
have Y% femoral length and Z% dental pathologies.  This methodology makes
the results gleaned from the analysis hard to dispute, but it makes it
extremely difficult to answer the question, What did you discover about
my ferret?  I try to preserve the double-blind protection of the data as
long as possible, but on rare occasion I am forced to break the double
blind seal.  If those results are made public, they are temporarily
deleted from the study so not to influence interpretations or donations.
For example, after discussing a problem seen in a ferret, several offers
of donations of ferrets with similar problems were made.  These could not
be used in the study because they were not randomly collected and would
have skewed the analysis.
 
Measurements are made with electronic calipers that send results directly
to spreadsheets in order to prevent recording error.  Bones and teeth
are placed in metal measuring jigs built specifically for that purpose
to increase precision of measurement.  Each measurement, such as the
diameter of the femur at midpoint, or the length of the carnassial,
is taken at least three times and the totals averaged.  If any of the
three measurements are not within agreement to 2.5% of the mean, it is
discarded and when possible a new measurement taken.  At the beginning of
each measuring session, measurements are made on several mink calibration
skeletons to insure results fall within 2.5% of each other.  Measurements
were often taken using different methods to check the accuracy of the
method.  For example, measurements of cranial capacity were taken with
tiny lead shot, glass balls, and fine sand, and compared to volumes
determined from measurements of endocranial casts.  Not all data were
measurements; some were recorded as the presence or absence of certain
traits, such as the absence of a specific tooth, or the presence of
reactive bone at the gum line (an indicator of periodontal disease).
Those measurements were easy; they were present or not.  Harder to
control was the arbitrary measurement of degree of change, such as the
amount of tartar (dental plaque) present on a tooth.  It was easy to see
the difference between little tartar and severe tartar, but try to tell
the difference between medium-moderate and heavy-moderate .  Using a
dozen volunteers, a 1 to 3 or minor-moderate-heavy scale was determined
to provide between 95 and 98% repeatability.  With a 1 to 5 scale,
repeatability by a single observer was only 82% and agreement between
observers was only 66%, which illustrates the difficulty of repeating
arbitrary observations.
 
The reason for this fanatical obsession with data collection is not
because I am particularly anal-retentive (just ask my kids who have
seen my lab and work areas I'm known as the Supreme Stacker of Stuff ).
Rather, it is because other studies along similar lines have not
controlled such variables and the studies have been rejected.  For
example, several studies of the osteology of ranched mink were used to
predict wild mink values, but were rejected when it was realized caging
and diet influenced the results.  The care and methodology of this data
collection process will (hopefully) prevent the results from being
discarded from some unforeseen question being left unanswered.
 
This extensive preamble has a specific goal as well; each reader has to
understand the data collected in this study is absolutely trustworthy.
This is because the data suggest conclusions that can be considered
controversial.  To be honest, what I discovered took me by surprise.  I
was so astonished at what I learned about ferret teeth that I went back
and measured everything again and I was still shocked.  My own personal
prejudices were challenged to such a degree that I was forced to the
library to research the findings.  I could argue interpretations, but I
couldn't dispute the data.
 
This study has placed me in an ethical dilemma; the data should be
published for other scientists to inspect and comment on, yet the results
suggest such profound health implications that for each day release is
delayed, harm can come to ferrets.  I ve decided to walk the fine line;
I will discuss the results, but will still try to preserve the specific
numeric data so it can still be published in a scientific journal.
Therefore, I won't give the exact numbers here; that is, you won't see
something like X individuals have Y pathologies.  However, I will be
quoting the most up to date percentages that summarize the data, such as
X% of the population has Y% of a problem (the individual numbers change
almost weekly as I continue to enter additional data, but the percentages
have more-or-less stabilized another indication the data is truly
random).  Some of these data will be published soon, but the rest MUST
wait until after the trips to Europe and New Zealand.
 
Those FML members with a strong science background will recognize the
controls for data acquisition of this study are of a high standard,
equal or exceeding those for most human medical studies.  Why is this
important?  It is the difference between pharmaceuticals and herbal
supplements.  Are herbals as effective as pharmaceuticals?  Some people
have the faith they are, but without the type of controlled data
acquisition required of the drug companies, you can NEVER be sure.  In
this case, you might not like what I have to say and you may disagree
with the conclusion, but you will not be able to argue the data is
tainted, inaccurate, unrepeatable, or invalid.  I welcome ANYONE who
can offer alternative hypotheses that can effectively explain the data.
If your idea fits the data better than my idea, I will readily admit it.
 
In the next few posts, I will be discussing the presence of tartar
(dental calculus), periodontal disease, worn teeth, broken teeth,
missing teeth, and dental abscesses.  There are plenty of other dental
pathologies that I have investigated and recorded, but these have the
most significance to this limited discussion.  With that, on to the
dental data.
 
Bob C
Questions?:  [log in to unmask]
Communications?  [log in to unmask]
[Posted in FML issue 4517]