When colonizers or conquerors appropriate the land of a lower race, we find a territory occupied at least for a time by two types of population, constituting an ethnic, social and often economic differentiation. The separation may be made geographical also. The Indians in the United States have been confined to reservations, like the Hottentots to the twenty or more "locations" in Cape Colony. This is the simplest arrangement. Whether the second or lower type survives depends upon their economic and social utility, into which again geographic conditions enter. The Indians of Canada are a distinct economic factor in that country as trappers for the Hudson Bay Company, and they will so remain till the hunting grounds of the far north are exhausted. The native agriculturists in the Tropics are indispensable to the unacclimated whites. The negroes of the South, introduced for an economic purpose, find their natural habitat in the Black Belt. Here we have an ethnic division of labor for geographical reasons. Castes or social classes, often distinguished by shades of color as in Brahman India, survive as differentiations indicating old lines of race cleavage. There is abundant evidence that the upper classes in Germany, France, Austria, and the British Isles are distinctly lighter of hair and eyes than the peasantry.[215] The high-class Japanese are taller and fairer than the masses. Nearly all the African tribes of the Sudan and bordering Sahara include two distinct classes, one of lighter and one of darker shade. Many Fulbe tribes distinguish these classes by the names of "Blacks" and "Whites."[216] The two-type people are the result of historical movements. [Sidenote: Differentiation and isolation.]