Oil and Water in Sudan 237
14 M Sahlins, 'The Segmentary Lineage: An Organization of Predatory Expansion.'
American Anthmpologisl, no 63, 1961. p 327.
15 A Southall, 'The Nuer and Dinka Are People: Ecology, Ethnicitg, and Logical
Possibility: Man, no 11, 1976.
16 R Kelly, TheNuerExpansion: TheShunure and Developmenl of an Expansionary
System, University of Michigan Press, Ann Arbor. 1985, p 69. Kelly's book
reviews the available history of migratory movements of Nuer and Dinka groups
during the last 170 years, establishes a chronology of the impact of Nuer aggres-
sion against the Dinka, and documents the failure of the latter to resist these
attacks, resulting in the wholesale expropriation of Dinka lands and cattle.
17 Established criticisms of environmental determinism regard it as simplistic and inca-
pable for explaining the varying outcomes that grow out of similar condjtions. But
it is nevertheless a truism that factors of climate and environmental shifts exert
impacts on populations over the longer term that include migration, warfare and
conflict, and cultural adaptations. Archaeological data demonstrate that even
among prehistoric subsistence populations such impacts and responses are hardly
simple (J L Jones, G M Brown, L M Raab, J L McVickar, W G Spaulding, D J Kennel.
A York, and P L Walker, 'Environmental lmperatives Reconsided Demographic
Crises in Western North America during the Medieval Climatic Anomaly." Current
Anthropology, no 40, 1999); rather, it posits "a complex, causal, and nonlinear rela-
tionship between people and their environment. J Haas and W Creamer,
Environmental lmperatives Reconsidered: Demographic Crises in Western North
America durinc - the Medieval Climatic Anomaly, Current Anthmpolog-,! ~ .. nn 40,1999.
p 160.
18 R Herring, 'The Influence of Climate on the Migration of the Central and
Southern Luo' in A B Ogot. Ecology and History in East Africa, Kenya Literature
Bureau, Nairobi, 1979, p 81.
19 R R Atkinson, The Origins of the Acholi of Uganda. Fountain Publishers,
Kampala, 1994.
20 Ominde, 'Ecology and Man in East Africa' in A B Ogot (ed.), Ecology and Hisrov
in Eost Africa, Kenya Literature Bureau, Nairobi, 1975, p 17.
21 Lienhardt, The Western Dinka, in J Middleton and Tate (eds), Tribes Without
Rulers, Routleadge and Paul Keegen, London. 1958. p 100. A Southall, 'The Nuer
and Dinka Are People: Ecology, Ethnicity, and Logical Possibility: Man. no 11,
1976, p 491.
22 Lienhardt, op cit.
23 Southall views the differences in Nuer and Dinka social organisation as products
rather than causes of the Nuer expansions.
24 Kelly, op cit, p 112.
25 Evans-Pritchard. The Nuer, Clarendon Press, London, 1940, pp 82-3. There is
also a minimum of about 16 cattle acceptable as payment (at that time), below
which the Nuer will not permit marriage.
26 Lienhardt, op cit, pp 99-100.
27 Kelly, op cit, p 97.
28 Southall, op cit, p 470.
29 Evans-Pritchard, op cit, pp 111-112.