those changes to a shift in the source of immigration from an easterly to a
westerly srream.s? Others emphasize internal dynamics, as farming com-
munities became increasingly specialized in their various micro-environ-
ments. 2 8 American James Denbow, for example, has shown how herding as
distinct from agriculture predominated in Botswana, on the verges of the
Kalahari Desert, where the rainfall was barely sufficient for agriculture.s"
Another unresolved question is whether the first mixed farmers to infil-
trate into Southern Africa used iron or whether iron-working
reached
Africa south of the Limpopo later by diffusion from the north. In central
Africa, agriculture and pastoralism seem to have preceded metallurgy. It
seems likely, however, that by the time farmers began to infiltrate south of
the Limpopo they knew how to produce iron tools and weapons.e?
Relations between Hunters and Herders
The incorporation
of domestic livestock into the economies of the ab-
original hunting and gathering people in the western part of Southern
Africa profoundly affected their way of life.3 1 Private property, previously
associated with such small, portable possessions as clothing (made from
skins) and weapons (bows and arrows), now included sheep and cattle.