Origin and Ancestry of Native Horses in Eastern Asia and Japan

Abstract

The domestication of the horse, like that of other farm animal species, should be understood as a gradual process, but in the period of about 3, 000 BC this process is considered to have developed remarkably in the grassland areas of Southeast-Europe. In the process of dispersion of the domesticated horses to the east, particularly up to the period of establishment of the Mongolian native horses, some gene-flow is considered to have possibly occurred from the wild Przewalsky horses to the domesticated stock. The origin of the Southeast Asian and Japanese native horses is undoubtedly the Chinese native horse. The Chinese native horses are classified into two types with different body size: the Mongolian horse and the Southwest mountain pony. Both of these two types are considered to have been more or leas influenced genetically by the Arab-Persian horses introduced from the west. The phylogenetic interrelationship between the two types of Chinese native horses should be clarified by comparative examinations of the two. It is possible that the Southwest mountain pony is only a dwarf type of the Mongolian horse, which has been adapted to draft and pull uses in mountaineous environment of the area. The small-sized native horses raised in a wide area of Southeast Asia have evidently originated from the stock of the Chinese Southwest mountain pony, and since then have been more or less genetically influenced by the West-European horses in and after the epoch of western colonization. The native horses raised in Northeast Asia, namely Korea and Japan, are considered to have mainly originated from the Mongolian horse. The breeding history of the Cheju native horses, Korea, suggests this fact. The reality of the theory that the small-sized horses in Okinawa and Amami Islands of Japan have originated from the Chinese Southwest mountain pony is questionable, because this theory has been founded on the inference that the horses have been raised since the Jomon period of Japan including the Southwest Islands, namely Okinawa and Amami island chain. Recent archeological excavations show that horse breeding in Japan began in the Kofun period. If this is correct, it is more reasonable to consider that the Mongolian-typed horses had been imported for the first time into Japan in the Kofun period through the Korean peninsula. Then, the small-sized native horses in the Southwest Islands of Japan are postulated as a dwarf type of the Japanese native horses which originally came from the mainland. Final clarification of this point waits for the accumulation of excavation data of horses the living age of which are ascertained chemically.