" The commission’s report concentrated on three related points. First, the claim that the Darfur conflict pitted ‘Arab’ against ‘African’ was facile. ‘In fact, the commission found that many Arabs in Darfur are opposed to the Janjawiid, and some Arabs are fighting with the rebels, such as certain Arab commanders and their men from the Misseriya and Rizeigat tribes. At the same time, many non-Arabs are supporting the government and serving in its army.’ Second, it has never been easy to sort different tribes into the categories ‘Arab’ and ‘African’: ‘The various tribes that have been the object of attacks and killings (chiefly the Fur, Massalit and Zeghawa tribes) do not appear to make up ethnic groups distinct from the ethnic groups to which persons or militias that attack them belong. They speak the same language (Arabic) and embrace the same religion (Muslim). In addition, also due to the high measure of intermarriage, they can hardly be distinguished in their outward physical appearance from the members of tribes that allegedly attacked them. Apparently, the sedentary and nomadic character of the groups constitutes one of the main distinctions between them’"
http://www.lrb.co.uk/v29/n05/mahmood-mamdani/the-politics-of-naming-genocide-civil-war-insurgency
"Even if you take the terms for granted, the majority of the “Arabs” in Darfur — the southern Rozayqat [Arab clans] — are not involved in the conflict. If you narrow the focus to those who are involved in the conflict, which is the northern Rozayqat, the Fur, the Masaleet, and the Zaghawah, then you realize that the distinction which best captures the difference between them is that the northern Rozayqat are those tribes in Darfur who received no [tribal] homeland, no “dar”, in the colonial dispensation, because the colonial dispensation did not give a tribal homeland to those who were fully nomadic and were thus without settled villages. At the same time, the colonial dispensation gave the largest homelands to peasant tribes with settled villages. At the same time, the colonial dispensation gave the largest homelands to peasant tribes with settled villages.
The conflict between the “dar-less” tribes and those with “dar” was triggered by an ecological crisis. According the United Nations Environmental Program (UNEP), the Sahara expanded one hundred kilometers over forty years. This came to a head in the 1980s pushing the nomadic tribes in the north down south and triggering a classical ecological conflict around the lush central Darfur mountains, the Jebal Marra."
http://sidgsudan.org/2009/02/26/analyzing-darfurs-conflict-of-definitions-interview-with-prof-mahmoud-mamdani/