Most archaeologists believe that the desert of the Sahara
is a combination of natural climate change and the activities
of humans. Archaeologists infer from the conduct of modern
pastoralists at the southern border of the Sahara that ancient
herders took little care to preserve their environment, allow-
ing their herds to overgraze land to the point that even sea-
sonal rains were not enough for plants to be able to renew
themselves. Except for a brief period of increased rainfall in
about 500 b.c.e., the Saharan desert has steadily expanded.
Th e cutting back of forests at the southern edge of the Sahara
by pastoralists and grain farmers is thought to have increased
the pace of climate change by reducing the moist updraft of
air generated by the dense African forest south of the Sarah.
Th e moisture released into the air would have been blown
northward, where it would have fallen as rain.
Th e nomadic pastoralists eventually became transhumant
populations, meaning that they migrated to diff erent grazing
areas according to the seasons. For instance, some Berbers,
perhaps including the Imazighen, known as the Meshwesh to
the Egyptians, would drive their herds into the Atlas Moun-
tains in spring, when rain caused new growth of grasses, and
then into the fl at lands in fall, where they could water their
herds at oases and wells. Th is practice continued until modern
times, when the seasonal rainfall became too little to sustain
the cattle, sheep, and goats of the local people.
It is not known exactly when people in southern Africa
began herding animals, though it was probably aft er people
began herding cattle in North Africa, because the cattle of
the people of southern Africa seem to have derived from
the cattle of the north. Th e fi rst animals to be herded were
sheep. Th e practice of herding sheep probably passed into
North Africa from the Near East and then through western
Africa south through the Kalahari and into the grasslands
of southern Africa. It is possible that herders from the Sa-
hara fl ed south to escape the desert, bringing their animals
and customs with them. One theory holds that several thou-
sand years ago southern Europe, North Africa, and western
parts of southern Africa were all one cultural group in which
knowledge of herding animals spread quickly. Archaeologists
cite similar painting styles in North Africa and Spain and
similar depictions of humans in paintings to link them with
western regions of southern Africa.
Herding cattle could have been transmitted in at least
three ways. One was through the western forests and thePetroglyph showing herders and cows, from Sahara Desert at Tassili, Algeria, North Africa (© Board of Regents of the University of Wisconsin System.
Photographer: Jeanne Tabachnick)
nomadic and pastoral societies: Africa 787