Kawarage

… [Kamei Setsuo]
[Domestic horses]

[Characteristics of domestic horses]
They are very similar to the Przewalski's horse and are often considered to be the same species, but they can be distinguished by a different number of chromosomes, a forehead, long hair on the tail growing from the base, and the ventral side of the body being the same color as the sides of the body. The original coat color of horses was yellowish gray with long hair and black on the lower parts of the legs, known as "kawara-ge," and this is seen in the only remaining wild horse, the Przewalski's horse, and in unimproved horses in various regions. However, domestic horses have been bred to come in a variety of coat colors.

*Some of the terminology that refers to "Kawarage" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…【亀井 節夫】
〔家畜ウマ〕

【家畜ウマの特徴】
　プシバルスキーウマによく似ていてしばしば同一種とされるが，染色体数が異なるほか，まえがみがあり，尾の長い毛は基部から生じ，胴の腹面は体側と同色などの点で区別できる。ウマの毛色は本来，黄灰色で長毛と四肢下部の黒い，いわゆる河原毛（かわらげ）と称されるものが基本型で，これは現存する唯一の野生馬プシバルスキーウマや各地の未改良馬に見られる。しかし，品種改良の進んだ家畜ウマではいろいろの毛色のものが生まれてきた。…

※「河原毛」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報