Persons with a tail ??? It's very unconceivable as a fact. There is an actual Ainu names such as "sar un kur", meaning "reed-field belonging person" or a person who lives in a reed-field. And "sar" does also mean "a tail", in addition to "reed-field". If I dare to compose a phrase that means "a person with a tail", it would be like "sar us kur".
Readers may now understand what I'm trying to say. Yes, the original meaning would have been "(I am) a person in reed-field" which was either maliciously or unintentionally recorded as "a person with a tail."
Note that ancient Japan was called by various names one of which is "central country of reed-field". Was Yoshino considered the center of the country? Izumo is usually considered the country, though.
Indeed, there is a place name called "kisa-tani" (kisa-valley) and "kisa mountain" in the region. I can present that "kisar" is another Ainu word for "reed field", here "ki" means "miscanthus" to be punctual.
Japan's ancient history has a native character called "Saru-ta-hiko". For the syllable "saru", a kanji that represents a monkey is used. A monkey has a tail... Well, anyway, I wonder whether or not this "sar" has anything to do with the reed-field. "Sar-toy" can mean a "reed soil (field). If "sar ta", it means "to cut reeds." The character is described as shining the upper country and the lower "reed-field" country in Kojiki. He is then to guide the invading people headed by Ninigi-no-mikoto to a destination. Did he open ways and lanes by cutting reeds ???