I stated in the last post that *any* organism can become domesticated.
However, since there is a "cost" for domestication--that is, the cost of
animal upkeep and care, loss of resources, etc.--not all organisms are
selected for domestication. This is especially true in marginal or
non-technological societies, where the cost of domestication outweigh the
potiential benefits. Some animals are clearly more suitable for
domestication than others and tend to have similar characteristics.
These charactistics include a) variation of some trait or attribute that is
desirable for humans (meat, fur, wool, milk, etc), b) the trait can be
consistantly bred, and c) there is a consistant heritable relationship
between parent and offspring that is not heavily influenced by the
environment. Interestingly enough, there are very similar to the criteria
necessary for natural selection to work, which makes sense since both
natural selection and domestication are different engines which power the
same vehicle, evolution. I term these criteria "primary characteristics."
There are other attributes, but not as universal. For example, dogs are
social, cats and ferrets are not; yet all three are domesticated.
Reindeer, cattle, goats, sheep and horses are herd animals; pigs, llamas,
and camels will certainly group together, but don't form the same complex
herd structures. I could continue to list similar characteristics that
seem to have built-in exceptions, but the point is made. This type of
criteria I term "secondary characteristics" and include such features as
hierarchical social structures, calm demeanor, etc.
Animals possessing both primary and secondary characteristics are especially
suitable for domestication. Those animals that were domesticated early in
the history of humans seem to have had both sets of characteristics, and
include the dog, cattle, goats, sheep, and chickens. These animals were
domesticated sometime between 5000 and 10,000 years ago, with a possible
exception being the dog which was even longer. Animals which have all the
primary characteristics, but are lacking in the secondary set seem to have
been domesticated later in human history, between 5000 years ago and the
modern historical era. These include cats, ferrets, and rabbits, among
others.
In the case of both the ferret and the cat, domestication followed the
widespread acceptance of domesticated plants. There appears to be a
correlation between the widespread dependence on cultivated foods and the
emergence of domesticated hunters capable of ratting and mousing duties. I
was asked once why I was so confident that ferrets were not domesticated in
Egypt, and the answer is simple; domesticated cats started appearing in
Egypt just after grain production became an important industry. The
historical records for ferrets follow the same trend for middle Europe. I
believe they were domesticated for similar purposes, which explains why both
lack some of the secondary characteristics and still have been domesticated.
Think of it this way. Say it "costs" $100 to domesticate a dog, but $1000
to domesticate a ferret (or cat), because it is harder to do and takes
longer. Before the widespread dependence on grain foods, $1000 was simply
too expensive and it wasn't worth the effort. But after agricultural
practices began leading to grain surpluses, which had to be stored for
future use or trade, the cost of grain loss to rodents became so high that
the $1000 domestication cost became acceptable. *NOW* there was a need to
domesticate a mouser/ratter. The ferret was born of human necessity.
Of course, agriculture was introduced into Europe earlier than 2500 years
ago (the estimated domestication point of the ferret), but those early
dates were mostly in the Mediteranean areas. Elsewhere, small, isolated
farming took place for the most part. Heavy agricultural practices leading
to large grain surpluses were not a primary industry in middle and upper
Europe until about the Roman era, which coincidentally corresponds to,
*gasp*, the first reliable records of the ferret. Cats were rare or
non-existent, the loss of grain to rodents was higher than the costs of
domestication, so polecats were domesticated into our fuzzy little ferrets
(The export of cats from Egypt was illegal until after Cleopatra died and
Rome crushed what remained of the Egyptian priesthood. It took additional
centuries for cats to become common place).
How long does it take to domesticate an animal? Believe it or not, Russian
researchers answered that question some time ago with breeding experiment
on fox. They found, and it has since been replicated, that traits of
domestication can be developed in just a few generations. Their experiments
showed that in just a few years, fox were "transformed" into dog-like
animals possessing pie-bald coloration, acceptance of humans, and
hypersexuality. Considering ferrets have been held and bred in capitivity
for at least 2500 years, there has been more than ample time for
domestication to take place.
What are some of the changes that occur in domesticated mammals like the
ferret? These seem be consistent from species to species, and although not
all domesticated animals possess all the traits, most possess most of them.
They include hypersexuality (a willingness to breed under artificial
conditions more than one time per year), decline in brain weight (and
attending skull changes and loss of intelligence), decline in parental care
behaviors (eatting or not suckling babies), decline in aggressive behaviors,
change in fur (Angora, curls), change in coloration (piebalding, albinism),
loss in species selectivity (attempts to breed with other species or
objects), juvenilization (the persistence of juvenile traits), failure to
thrive outside of human captivity, dental changes (extra or missing teeth),
and changes in body size, weight or proportions (dwarfing, giantism). At
one time or another, ferrets have shown all of these traits.
Bob C and 19 MO
[Posted in FML issue 2386]
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