A Cross-Cultural Study on the Degree of Fluid Residential Groupings of Settlement Dwellers among Hunter-Gatherers with Special Reference to the Ainu and Orochon

世界の狩猟採集社会の特徴の一つとして集団の空間的流動性があげられる。これまで複数の異なる民族を対象として流動性の程度を比較した研究例はほとんどみられなかった。本研究の目的は，アイヌとオロチョンを例に，集団の空間的流動性の程度を比較することである。分析の結果，以下のことが明らかとなった。集落共住率（U）を算出した結果，同一集落内に定住する傾向が強く集落を構成する家があまり変化しなかった紋別場所のアイヌでは，集落共住率（U）が0.9∼1.0である家の総家数に占める割合は73%ほどであった。一方，多くの家が集落間で移動する傾向が強く集落構成が流動的に変化していた三石場所のアイヌでは，集落共住率（U）が0.9∼1.0である家の総家数に占める割合は43%ほどであった。三石場所のアイヌと同様に，集落構成が流動的に変化していたオロチョンでは，集落共住率（U）が0.9∼1.0である家の総家数に占める割合は25%とさらに低く，0.1∼0.2の家は33.3%，0.3∼0.4の家は25%であった。13年間における集落共住率（U）の経年変化をみると，オロチョンの値は常に0.11∼0.33であり，三石場所のアイヌよりも下回っていた。アイヌの事例を1戸ずつ検討しても，集落共住率（U）の値が常に0.4未満であるような事例は1例もなかった。アイヌ社会のなかでも三石場所のアイヌ集落においては集団の空間的流動性が大きかったが，オロチョンの一家の場合にはさらに流動性が高かった可能性がある。Membership within a residential group was not stable in hunter-gatherer societies, such as those of the San (Bushman), Mbuti Pygmy, Hadza, Hare Indian, Inuit, Orochon, and Ainu. So far the differences of the degree of fluid residential groupings among hunter-gatherers have not been revealed well. The purpose of this study was to measure the degree of fluid residential groupings of settlement dwellers between the Ainu and Orochon by making use of a co-residing ratio (U), and to consider the backgrounds of their differences.The numerical value of the co-residing ratio (Ui) of the household i was calculated as follows:Ui=mi / MiMi:the number of households that resided with household i at the same settlement in one year and also resided at any settlement after a given number of years. Mi≥1.mi:the number of households that resided with household i at the same settlement in one year and also resided with household i at any settlement after a given number of years, including household i.The numerical value of the degree of the co-residing ratio (U) per household was within the range of 0 to 1. When the degree of the co-residing ratio (U) increases from 0 to 1, the fluidity of residential groupings of settlement becomes lower.When we focused on the 74 Ainu households that resided at any settlements in 1856, 1862, and 1868 in the Monbetsu district, a given number of years of the co-residing ratio（U） was six years for each time frame 1856-1862 and 1862-1868. The co-residing ratio （U） was 0.9～1.0 in about 73% of 144 households. Samely when we focused on the 46 Ainu households that resided at any settlements in 1856, 1858, 1864, 1865, 1868, and 1869 in the Mitsuishi district, a given number of years of the co-residing ratio （U） was two years, six years, one year, three years, and one year for each time frame. The co-residing ratio （U） was 0.9～1.0 in about 43% of 230 households. On the other hand, when we focused on one Orochon household in 1910, 1925, 1928, 1932, 1935, 1938, 1945, 1947, and 1957, one Orochon household in 1900, 1920, 1921, and 1931, and one Orochon household in 1908 and 1913, the co-residing ratio （U） was 0.9～1.0 in only about 25% of 12 households. In the Orochon households 33.3% of 12 households showed 0.1～0.2 degree of the co-residing ratio （U）.Next, when we focused on the 46 Ainu households that resided at any settlements in all time frames 1856, 1858, 1864, 1865, 1868, and 1869 in the Mitsuishi district, and one Orochon household that resided at any settlement in all time frames 1925, 1928, 1932, 1935, and 1938, the numerical value of the co-residing ratio （U） of Orochon was lower than that of the Ainu in the Mitsuishi district during almost all thirteen years.Therefore it is postulated that the degree of fluid residential groupings of settlement dwellers was higher in the Orochon than in the Ainu, and was higher in the Mitsuishi district than in the Monbetsu district. And also it is estimated that the Orochon settlement was formed mainly by moved households and the Ainu settlements in the Mitsuishi district were formed by moved households and stayed households, and the Ainu settlements in the Monbetsu district were formed mainly by stayed households