How Was The Ferret Domesticated?
 
Of all the questions regarding the domestication of animals, this is
perhaps one most impossible to answer without the use of a temporal
displacement device and the mentorship of Jules Verne.  Fortunately, we
are talking about the ferret, which--like the cat--is a special case that
allows us to rule out most methods of domestication, so even though the
conclusion cannot be proved, it at least can be arguably probable.
 
There are numerous ways to domesticate an animal, including one novel
idea that animals can domesticate themselves.  Of this last hypothesis,
all I can say is the idea is extremely controversial.  Over the years,
one student of domestication or another has postulated that dogs, cats,
and even cattle, goats, and sheep domesticated themselves by close
association with humans.  Like recent religious converts, the proponents
of this idea offer "just so" stories as scientific fact, but really
offer little evidence that conclusively supports their contention.  For
example, the argument Egyptian wild cats domesticated themselves fails
to answer why the same subspecies of wild cats that were domesticated in
ancient Egypt still exist wild in Egypt today.  It also fails to explain
why other animals, such as civets, genets, martens, polecats, weasels,
mongooses, rats, deer mice, and scores of other species that live in
close habitation with humans are not domesticated.  It is a good idea,
and it brings focus on some questions previously ignored, but it
ultimately fails because domestication--by definition--is a human
process.  If animals do it themselves, it is called adaptation, and
numerous animals have adapted themselves to survive in close human
contact and remain undomesticated.  This is not just a nit-picky
distinction; if you want to understand how an animal was domesticated,
you need to be able to distinguish animal adaptation from human changes,
so such a distinction is of paramount concern.  Cockroaches, house mice,
body lice, and sewer rats live in close association with humans, but they
are clearly not domesticated.  Why?  Because for an animal to be
considered domesticated, their reproduction has to be controlled by
people.
 
Ferret reproduction is clearly controlled by people, even when humans are
breeding them back to wild populations.  This doesn't make the ferret
less domesticated; it simply makes them less reliable.  At this point in
time, how the process of domestication changes the genetic information
in the domesticated animal is not well understood.  It changes genes that
occur at low-frequency rates into genes that occur in high-frequency
rates, but perhaps the interaction of those genes are more important
than the actual changes.  It is not the invention of new genes, but a
shift in the frequencies of existing ones that drives the changes seen
in domestication, which is why breeding ferrets back to polecats (called
introgression) is such a dangerous practice--you simply cannot predict
how the offspring will behave.
 
Take a step back from the question a bit and consider how the genes are
flowing.  Domestication is a process of genetic manipulation; you breed
animals to change the frequency of specific genes (the gene frequencies
are changed even if you are not aware of the ones you are changing).  If
a domesticated ferret escapes and breeds with a polecat, introducing
"domesticated" genes into the wild population, what happens?  (Note: I
placed the term "domesticated" inside quotes because there is really no
such thing as "domestication genes" that make an animal domesticated; I
am using the term for conveniences' sake only).  The answer is,
ultimately, nothing.  Those animals with "wild genes" will survive better
in the wild than those hybrids with "domesticated genes"; simple natural
selection.  Even if the hybrid survived and bred, they would breed to
other wild polecats, so the effect of domestication will be minimized and
lost after a few generations.  There might be a few genes that are
slightly different that did not impact the fitness of the animal, and
certainly the mitochondrial DNA would be messed up making it difficult
to trace ancestry, but all-in-all, no big change.
 
So, what about the "wild" gene flow into the ferret?  The same thing;
no one wants a nervous ferret that bites regardless of handling, so
they aren't as popular.  But even if you continue to bred the line to
non-hybrid ferrets, the "wild" genes are diluted in a surprisingly few
number of generations, becoming "domesticated," and you are essentially
back to where you started only you have lived through a few generations
of nasty, biting ferrets for your trouble.  And, you have seriously
screwed up the ability of geneticists to use the genetic information to
trace ancestry.  It was common practice to occasionally breed the ferret
to polecats in improve their hunting abilities.  I think this habit of
ferreters to bred the ferret to polecats is largely responsible for the
public perception that ferrets are "nasty biters."
 
The point here is not JUST that it is a really bad idea to breed ferrets
to polecats, but that if you allow a domesticated animal to bred to
wild ones, it will never become domesticated because you are not
reproductively isolating the population.  There will be really no shift
in the animal's genes that create the effect of domestication and all you
will have is a tamed animal, not a domesticated one.  It is the genetic
isolation of the human-controlled group from the wild one that is at the
core of domestication.
 
Why is this important?  Because if you have a domesticated animal, you
KNOW they were purposely bred to be that way.  That means there was human
intent for the ferret to be domesticated, which means people purposely
isolated the breeding of a number of wild animals until the captive
population was genetically different, and then they preserved those
changes by maintaining that genetic isolation.  In the case of ferrets,
this represents mostly reproductive and behavioral changes.
 
Some of the questions of the "how" of ferret domestication may never be
answered.  For example, were ferrets caged in small groups, or were they
penned up in larger ones?  Were there only a few people per village with
ferrets with a large population in the surrounding areas, or were there
a lot of ferrets in a rather limited area?  Were ferrets an object of
trade, with groups actively trying to obtain them, or were they spread
by word of mouth and person-to-person contact?
 
While these types of questions cannot be answered without extensive
archaeological work, we can be sure of one thing: ferrets were
reproductively isolated from polecats in order to produce an animal with
clear traits of domestication.  That means they were housed in a manner
so they would not escape.  While the manner of housing must have changed
over the years, I would expect much of the practice to be virtually
identical to those practices from the last century or so.  My best guess
is that ferrets were domesticated from polecats by housing the animals in
small pens or cages, and only breeding those that were tamed towards
humans; the practice of "breeding for tameness" would explain ALL traits
of domestication currently seen in ferrets.
 
Bob C  [log in to unmask]
 
"How to Hunt Rabbits: The rabbit likes his warren, but spends his nights
roaming in the broom, the long grass and the brambles looking for his
favorite herbs.  If flushed out by a spaniel or greyhound, he is off in a
zig-zagging run, or jumps into a burrow around which a siege is
organized.  Fine nets are put over the holes and a ferret is sent down
the only one left free; he wears a muzzle so that he can't kill the
rabbits, devour them and appear days later after sleeping it off.  If
there is no ferret available, then a piece of cloth rubbed with sulphur
and incense is burnt and shoved into the burrow.  Disturbed by the smell
of the ferret or the smoke, the rabbits soon rush up into the nets where
slaughter and a place in the stew await them.
Gaston Phoebus 1387-1388, Illuminated Manuscript 1405-1410 "The Hunting
Book".
[Posted in FML issue 4777]