The domesticatedred fox is a form of the wild red fox which has been domesticated to an extent under laboratory conditions. They are the result of an experiment which was designed to demonstrate the power of selective breeding to transform species, as described by Charles Darwin in On the Origin of Species. The experiment explored whether selection for behaviour rather than morphology may have been the process that had produced dogs from wolves, by recording the changes in foxes when in each generation only the most tame foxes were allowed to breed. Many of the descendant foxes became both tamer and more dog-like in morphology. The program was started in 1959 in the Soviet Union by zoologist Dmitry Belyayev and it has been in continuous operation since. Today, the experiment is under the supervision of Lyudmila Trut in Russia, at the Institute of Cytology and Genetics in Novosibirsk. In 2020, a review found that the results of the "Farm fox experiment" had been overstated, and that the "wild" population it was based on had originated from a captive population from Canada that had been bred there since the 1800s.
Genetic experimentation
Initial premise and hypothesis
The experiment was initiated by scientists who were interested in the topic of domestication and the process by which wolves became domesticated dogs. They saw some retention of juvenile traits by adult dogs, both morphological ones, such as skulls that were unusually broad for their length, and behavioral ones, such as whining, barking, and submission. In a time when centralized political control in the fields of genetics and agriculture promoted Lysenkoism as an official state doctrine, Belyayev's commitment to classical genetics had cost him his job as head of the Department of Fur Animal Breeding at the Central Research Laboratory of Fur Breeding in Moscow in 1948. During the 1950s, he continued to conduct genetic research under the guise of studying animal physiology. Belyayev believed that the key factor selected for in the domestication of dogs was not size or fertility, but behavior: specifically, tameability. Since behavior is rooted in biology, selecting for tameness and against aggression means selecting for physiological changes in the systems that govern the body's hormones and neurochemicals.
Experimentation
Belyayev decided to test his theory by domesticating red foxes; in particular the silver fox, a dark-colored mutation of the red fox. He placed a population of them under strong selection pressure for inherent tameness. According to Trut: Belyayev and Trut believed that selecting for tameness mimics the natural selection that must have occurred in the ancestral past of dogs, and, more than any other quality, must have determined how well an animal would adapt to life among humans.
Results
Russian scientists achieved a population of domesticated red foxes that are fundamentally different in temperament and behavior from their wild forebears. Some important changes in physiology and morphology became visible, such as mottled or spotted colored fur. Some scientists believe that these changes obtained from selection for tameness are caused by lower adrenaline production in the new population, causing physiological changes within relatively few generations yielding genetic combinations not present in the original species. This indicates that selection for tameness produces changes that are related to the emergence of other dog-like traits. These seemingly unrelated changes are a result of pleiotropy.p. 5 The project also bred the least-tameable foxes to study social behavior in canids. These foxes avoided human contact, as do their wild behavioral phenotypes. Similar research was carried out in Denmark with American minks.
Current project status
Following the demise of the Soviet Union, the project ran into serious financial problems. In 2014, officials stated that the number of foxes was never reduced and is still stable at about 2,000., there are 270 tame vixens and 70 tame males on the farm. In another published study, a system of measuring fox behavior was described that is expected to be useful in QTL mapping to explore the genetic basis of tame and aggressive behavior in foxes. The sculpture "Dmitriy Belyaev and the Domesticated Fox" was built near Institute of Cytology and Genetics the honor of the 100th anniversary of the birth of Dmitry Konstantinovich Belyaev. The tamed fox gives the scientist a paw and wags its tail. Konstantin Zinich, sculptor says "The philosophy of touching a fox and a man is rapprochement, kindness, there is no aggression from the fox – it was wild, and he made it genetically domesticated."
Morphology
Domesticated red foxes exhibit a variety of coat color mutations, including red, cross, silver, platinum, and Georgian white, the lattermost being a color exclusive to the Russian breeding project.
Ancient attempts
Archaeologists have discovered evidence of red fox breeding in the late Iron Age on Orkney, off the northern coast of Scotland. After the attack of the Vikings in Scotland around A.D. 800, the breeding is said to have stopped.
