[morpheos137]

The Zulu warriors were supposed to be celibate. So they had plenty of pent up rage.

EDIT:

For the downvoters see

http://smu-facweb.smu.ca/~wmills/course316/9Zulu_Shaka.html

>units of unmarried females were assigned to each impi to prepare food and perform other domestic duties. However, Shaka insisted on abstinence from sexual activities among his warriors (like some football and soccer coaches today). Any woman who became pregnant, along with her lover, would be immediately put to death. Nor did Shaka allow his warriors to marry until he gave permission, which he did infrequently and only when the regiment was being retired. Then, he would order the entire regiment to marry and would specify the unit among the women that they were to marry (kind of like Rev. Moon).

[YeGoblynQueenne]

You're right about Shaka imposing celibacy, but my understanding is that it was only Shaka that did this and subsequent ruleres let their men free to breed as they saw fit. At Isandlwana Shaka was long gone and there was no celibacy rule, as far as I know - but I may be wrong of course.

[AussieWog93]

They also got high as a kite before they fought.