Africa Geography Quiz #2

Hutus and tutsis have been around long before Europeans came to Africa. The Belgians, however, started classifying each tribe based mainly on perceived (and generally stereotypes) physical differences which also favoured Tutsis over Hutus and led to their resentment of the other, and as such played a big part in laying the groundwork for the eventual Rwandan genocide. The only reason that they "aren't real ethnic groups" is that scientific evidence is extremely inconclusive that the two are truly a separate people, especially after centuries of intermarriage. And I'm willing to bet Rwanda is more than willing to play up the "oh, we're all just one tribe after all" angle after that happened too.

The points about shared language, religion, and so on, are correct. I think Hutu and Tutsi designated differences between predominantly farming and predominantly cattle-raising people. The distinction also had hierarchical aspects and worked in some ways like castes. There seems to have been some fluidity between those identities, in ways that are uncommon with most understandings of ethnicity. One could become Tutsi, for example, through marriage, or through a change in occupational status. When the Belgians came, they decided to further privilege Tutsi people in a variety of ways, both in Rwanda and in Burundi. This included rigidifying the classifications and requiring passes stating one's ethnicity. Much resentment resulted, helping to explain (rather than justify) later history. (I'm relying heavily on Rene Lemarchand and Mahmood Mamdani for this.)