(3) While the Gogo attempt to base their livelihoods on sorghum and millet cultivation, they use these grains to make investments into cattle. In addition to providing economic insurance, the cattle symbolize the complex networks of personal relationships. However, in recent years, interest in cattle husbandry has diversified among households.
          During previous research, the livestock of all households in the research village were calculated during three years (2001-2003). Those data were analyzed in order to find trends in the transformation of the economic differentiation structure of the village. Households were grouped into four wealth strata, Extra rich (owners of more than 251 heads of cattle), Rich (101-250), Middle (51-100), and Poor(1-50). As a trend during the three years, Rich households acquired more cattle to become Extra rich, while many Middle/Poor households reduced their number of cattle. Thus, the excessive concentration of cattle ownership among the Extra rich/Rich has accelerated.
          During this research (February 5-22, 2004), case studies of progress in adding/reducing cattle were gathered in order to clarify the mechanism behind the excessive concentration. As a result, the following were clarified:

1. The disparity between the Extra rich and Rich is caused by cash income from their cattle trade businesses. However, this business can be a precarious one due to external conditions, such as the market price of cattle. Therefore, the Extra rich are so eager for good partners that they hire even from among non-kin. Thus, a lasting excessive concentration by the Extra rich is not likely to occur.
2. Once Middle/Poor households lose their cattle, very few are able to recover such ownership. This is because the negative economic valuation of cattle ownership has spread, freeing them to venture out as migrant workers. Middle/Poor households constitute fluid labor power, though they carry out grazing for the Extra rich/Rich through contracts for cattle trusteeship.
3. According to 1. and 2., a bipolarization is unlikely to occur given this economic differentiation. In general, the mobility of Middle/Poor households will be a crucial factor for the transformation of this structure of economic differentiation.