Useful information about the ethnic composition of the Janjaweed, the primary sedentary tribes targeted in Darfur, and the perception of ethnic differences in Darfur can be found in the International Commission of Inquiry on Darfur's Report to United Nations Secretary-General Kofi Annan. Excerpts from this report are found below:
The fact that the Janjaweed are described as Arab militias does not imply that all Arabs are fighting on the side of the Janjaweed. In fact, the Commission found that many Arabs in Darfur are opposed to the Janjaweed, 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. Thus, the term “Janjaweed” referred to by victims in Darfur certainly does not mean “Arabs” in general, but rather Arab militias raiding their villages and committing other violations (page 32).
Tribes in Darfur
The various tribes that have been the object of attacks and killings (chiefly the Fur, Massalit and Zaghawa tribes) do not appear to make up ethnic groups distinct from the ethnic group 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. Furthermore, inter-marriage and coexistence in both social and economic terms, have over the years tended to blur the distinction between the groups. Apparently, the sedentary and nomadic character of the groups constitutes one of the main distinctions between them. It is also notable that members of the African tribes speak their own dialect in addition to Arabic, while members of Arab tribes only speak Arabic (page 129).
[I]n recent years the perception of differences has heightened and has extended to distinctions that were earlier not the predominant basis for identity. The rift between tribes, and the political polarization around the rebel opposition to the central authorities, has extended itself to issues of identity. Those tribes in Darfur who support rebels have increasingly come to be identified as “African” and those supporting the government as the “Arabs”. A good example to illustrate this is that of the Gimmer, a pro-government African tribe and how it is seen by the African tribes opposed to the government as having been “Arabized”. Clearly, not all “African” tribes support the rebels and not all "Arab” tribes support the Government. Some “Arab” tribes appear to be either neutral or even support the rebels. Other measures contributing to a polarization of the two groups include the 1987-1989 conflict over access to grazing lands and water sources between nomads of Arab origin and the sedentary Fur. The Arab-African divide has also been fanned by the growing insistence on such divide in some circles and in the media. All this has contributed to the consolidation of the contrast and gradually created a marked polarisation in the perception and self-perception of the groups concerned (page 130).