the taming and adaptation of wild animals to meet the economic needs of man.
Domestication, whose origin dates to about 10,000–15,000 years ago, constituted an important stage in the development of society’s productive forces, since it led to the rise of livestock breeding. It is difficult to date precisely its beginnings because the changes that the animals had undergone in the early stages of domestication had not affected the skeletal structure, and consequently, the animal bones found in the excavations of Upper Paleolithic settlements are not distinguishable from the bones of wild animals. Thus, the initial stages of domestication can be evaluated chiefly from the data obtained in modern fur farming and elk and maral breeding, as well as from experiments, which in the USSR are conducted mainly at the Askaniia-Nova Preserve.
In the process of domestication, animals lived under conditions created for them by man (construction of pens, provision of pasturage and feed supplements), which differed markedly from those of their wild ancestors. The more effort man expended on obtaining animals with the desired characteristics, the greater the changes the animals underwent. Domestication was made possible through artificial selection and limited natural selection and was accompanied by morphological and physiological changes in the animals.
Most domestic animals are characterized by sharp morphological and physiological differentiation (sometimes on the specific or generic level) with preservation of complete hereditary compatibility, by simplification of behavioral responses, by a reduction of brain size, by a decline in the reactivity of the nervous system, and by hyperfunction of the sexual glands and hypofunction of the adrenal glands. Other characteristic features are underdevelopment of certain organs and tissues that have lost their initial purpose (changes in integumentary tissues, reduction of ear muscles), increased heterozygosity, high phenotypic stability under changing environmental conditions, changes in the phenotypic expression of mutations under the effect of an altered gene pool (for example, the platinum fox), and a general increase in variability. When the changes brought about by domestication are extensive, especially if there is great specialization for certain types of productivity, reversion to a wild state is impossible.
Ancient frescoes, particularly Egyptian ones, show that some animals not now domesticated (mainly various species of antelopes) had been domesticated at one time. Certain modern domestic animals, for example, donkeys and camels, are threatened with a sharp reduction in their numbers (owing to the reduced need for them as draft animals) if no new, economically justified use is found for them.
S. N. BOGOLIUBSKII and S. S. SHVARTS