I want to thank Olivier for his wonderful posts!  I think of keeping
ferrets as an international--rather than a national--pastime, so I love
seeing posts from other countries.  Translating is hard, so I really
appreciate the effort made to post.  Thanks, not only for the wonderful
effort to post in English, but also for reminding us that having pet
ferrets is not solely an American pastime.
 
Olivier has brought up an issue that on the surface seems complex, but is
actually quite simple.  Because modern taxonomy is designed to explain
evolutionary relationships, not only do species names change to reflect
revised understandings, but also taxonomic classifications change for the
same reasons.  Remember, in nature, the only thing real is the species;
all other taxonomic units are arbitrary, designed to be a tool for
understanding relationships, but not really tangible in a physical
sense.  Even subspecies are more construct than actual; it is sort of
like saying Mustangs with blue hardtops are significantly different from
those with red ragtops.  The designation of "subspecies" is designed to
describe a local subpopulation with distinctive regional characteristics,
usually caused by a shift in gene frequencies as the species adapt to
local conditions, NOT to indicate something is "almost it's own species."
Political agencies tend to view subspecies as either a species in their
own right, such as with the Florida panther (a subspecies of Felis
concolor, the puma) and the Key deer (a subspecies of Odocoileus
virginiana, the white-tailed deer).  Some biologists tend to see
subspecies as "incipient species;" that is, a group of animals that
has the potential of becoming a species in their own right.  It is very
controversial and rather arbitrary.
 
Allow me to use black-and-white photography as an example of the problem
in defining a species, or in this case a subspecies.  If you have ever
used the Zone System, you know the entire range of tone from black to
white is broken into 10 (or 11 or more in some schemes) zones of
brightness, ranging from pure black to pure white.  We all realize you
could divide the gray scale into 20, 30, or even a million different
zones; whatever division we make is totally arbitrary.  In Ansel Adams'
case, the film technology of the time made his divisions appropriate, but
with modern film technology, the divisions might be considered limited.
It is the same way with defining a subspecies; ANY division is arbitrary,
a division made by conventional definition.  With modern gene technology,
scientists are discovering what was once thought to be major genetic
differences are now seen to be (in many cases) a combination of gene
expression, phenotypic plasticity, and adaptation to local environments.
These factors change the phenotype of the animal, making it seem to
be significantly different from members of the same species found in
other locales.  The problem is, not all changes in phenotype reflect
significant differences in the genome.  That is what some have found in
the European polecat.  What were considered enough differences to assign
subspecies status are now being attributed to phenotypic plasticity and
other environmental factors rather than changes in gene frequencies for
specific traits.  In short, they are not all that different.  In fact,
as a group, European polecats are so similar genetically that they have
been described as "a species with little variation."
 
I could discuss the issues of subspecies all day long, but the real
issue is, are previously accepted subspecies of the European polecat
now considered valid (especially Mustela putorius berberii)?  The answer
is no.  Yes, in the past, taxonomists accepted a half dozen or more
subspecies for the European polecat, but no longer.  What you are forced
to do is consult the most modern published authorities, which in this
case would be
1) Wilson and Reeder's 1993 "Mammal Species of the World: A Taxonomic and
Geographic Reference," 2nd edition,
2) Mitchell-Jones, et al 1999 "The Atlas of European Mammals," or
3) Griffiths 2000 "Mustelids in a Modern World."
 
In "The Atlas of European Mammals," Birks (p. 336) says of the polecat,
"Geographic Variation: Variability slight and no subspecies currently
recognized."  In "Mustelids in a Modern World," Davison (p. 155) says
"Since it is unknown whether ferrets were domesticated from the European
polecat, Mustela putorius, or their eastern European congener, the steppe
polecat, Mustela eversmannii, they are usually given species (rather than
subspecies) status as Mustela furo."  Most important, in "Mammal Species
of the World: A Taxonomic and Geographic Reference" Wozencraft (p.
323-324) does NOT list "berberii" in the list of synonyms for Mustela
putorius.  I could list a dozen more, but these will do for this level
of discussion.
 
The implications of these three references are
a) the term "Mustela putorius berberii" is not a valid designation,
b) there are NO valid subspecies of the European polecat, including
Mustela putorius furo,
c) the ferret's scientific designation is Mustela furo, and
d) the progenitor for the domesticated ferret is unknown.
 
To continue, regardless of how many older references can be found to
support whatever number of subspecies that might or might not exist for
the European polecat, modern genetic studies have rendered them invalid.
Further, even IF the subspecies Mustela putorius berberii existed for
the European polecat, the point is moot; the Berber subspecies cannot be
the progenitor of the domesticated ferret if the species that gave rise
to our pet, either the European or the steppe polecat, is unknown.
 
There is one thing in Olivier's post that got my undivided attention--the
reference to Pierre Delattre and Roger Martine's 1988 work.  I have just
about every reference published on polecats (and mustelids in general),
including many by Delattre and Martine, but I am unaware of this one.  It
is not in Biological Abstracts, it is not listed in any of my reference
books, I can't find it in WorldCat or the Zoological Record.  Could you
please send a more complete reference so I can obtain a copy?  Thanks!
 
Bob C
[Posted in FML issue 4088]