Just compare a river map of West Africa to a map of West African kingdoms.
You can clearly see that all of these kingdoms form around the Niger River.
More support to this: None of these other rivers are even in Africa: The Thames is in England, the Indus is in Pakistan, and the Euphrates runs through the Middle East.
The answer is: <u><em>securing workers’ compensation</em></u>
The reason for this is that Romans were at the time a very highly developed civilization while the Huns, together with other tribes with which the Romans have dealt with in previous decades, were mostly nomads who did not have permament and grand settlements such as Rome at the time for example. For that reason, this might have made historians like Ammianus be inclined to think that Huns were savage brutes without the capability to think.