FEATURE ARTICLE
Early Canid Domestication: The Farm-Fox Experiment
Foxes bred for tamability in a 40-year experiment exhibit remarkable transformations that suggest an interplay between behavioral genetics and development
Lyudmila Trut
The Experiment
In setting up our breeding experiment, Belyaev bypassed that initial
trauma. He began with 30 male foxes and 100 vixens, most of them
from a commercial fur farm in Estonia. The founding foxes were
already tamer than their wild relatives. Foxes had been farmed since
the beginning of this century, so the earliest steps of
domestication—capture, caging and isolation from other wild
foxes—had already left their marks on our foxes' genes and behavior.
From the outset, Belyaev selected foxes for tameness and tameness
alone, a criterion we have scrupulously followed. Selection is
strict; in recent years, typically not more than 4 or 5 percent of
male offspring and about 20 percent of female offspring have been
allowed to breed. To ensure that their tameness results from genetic
selection, we do not train the foxes. Most of them spend their lives
in cages and are allowed only brief "time dosed" contacts
with human beings. Pups are caged with their mothers until they are
11/2 to 2 months old. Then they are caged with their litter
mates but without their mothers. At three months, each pup is moved
to its own cage.
To evaluate the foxes for
tameness, we give them a series of tests. When a pup is one month
old, an experimenter offers it food from his hand while trying to
stroke and handle the pup. The pups are tested twice, once in a cage
and once while moving freely with other pups in an enclosure, where
they can choose to make contact either with the human experimenter
or with another pup. The test is repeated monthly until the pups are
six or seven months old.
At seven or eight months, when the foxes reach sexual maturity, they
are scored for tameness and assigned to one of three classes. The
least domesticated foxes, those that flee from experimenters or bite
when stroked or handled, are assigned to Class III. (Even Class III
foxes are tamer than the calmest farm-bred foxes. Among other
things, they allow themselves to be hand fed.) Foxes in Class II let
themselves be petted and handled but show no emotionally friendly
response to experimenters. Foxes in Class I are friendly toward
experimenters, wagging their tails and whining. In the sixth
generation bred for tameness we had to add an even higher-scoring
category. Members of Class IE, the "domesticated elite,"
are eager to establish human contact, whimpering to attract
attention and sniffing and licking experimenters like dogs. They
start displaying this kind of behavior before they are one month
old. By the tenth generation, 18 percent of fox pups were elite; by
the 20th, the figure had reached 35 percent. Today elite foxes make
up 70 to 80 percent of our experimentally selected population.
Now, 40 years and 45,000 foxes after Belyaev began, our experiment
has achieved an array of concrete results. The most obvious of them
is a unique population of 100 foxes (at latest count), each of them
the product of between 30 and 35 generations of selection. They are
unusual animals, docile, eager to please and unmistakably
domesticated. When tested in groups in an enclosure, pups compete
for attention, snarling fiercely at one another as they seek the
favor of their human handler. Over the years several of our
domesticated foxes have escaped from the fur farm for days. All of
them eventually returned. Probably they would have been unable to
survive in the wild.
» Post Comment