How mosquitoes 'fought for' the Bantu as they migrated, and other surprising ways African groups became dominant

Many things that we today think of as quite ordinary - such as maize and salt - have had a huge impact on Africa's history and development.

STORIES of conquest in Africa are often centered on the role of  among others technology, food, trade and capitalism, but little is known of how these conflated to contribute to the rise—and demise—of many groups on the continent.

Yet it can be fascinating: one reason why Bantu farmers were able to displace the pygmies in equatorial Africa, and some groups of the Khoisan of southern Africa, is food: the latter lived in an area where the wild plants were simply difficult to domesticate into food crops, and stood no chance in the face of expanding Niger-Congo groups armed with better adapted plants.

Mail & Guardian Africa looks at how five unlikely agents caused major change on the continent. You may never quite look at them in quite the same way again: 


Malaria is thought of today as largely an “African” problem –while the disease has been eliminated in much of the rest of the world, 90% of the burden is concentrated in Africa.

But globally, there is probably no disease that has shaped human history as much as malaria, as brilliantly articulated by Sonia Shah in her delightful book The Fever. Malaria has been the hidden hand in the rise and fall of peoples, cities and civilisations, from ancient Rome to Panama and the American colonies.

In Africa, malaria was a primary factor in Bantu migration across central, eastern and southern Africa. The Bantu are thought to have originated somewhere in Cameroon/Congo, and were farmers. The pools of dirty water created by their forest clearances were the perfect breeding ground for mosquitoes – and malaria.

Because they lived in villages, they were exposed to year-round plasmodium infections. It killed many babies and children, but those who survived had strong immunity against the disease. As they moved across Africa, they encountered nomads and hunter-gatherers whom they sometimes fought for territory.

But more often than not, the Bantu didn’t have to fight at all, Shah writes. A couple of bites from the mosquitoes that travelled along with them did the trick in beating back incursions from their non-immune adversaries, “as effectively as a standing army.”

Tsetse fly

The tsetse fly, like the mosquito, is a vector of a parasitic disease. In the tsetse’s case, it carries trypanosomiasis, which is better known as sleeping sickness in humans and nagana in animals. Bovine (such as cattle and buffalo) and equine (horses, donkeys and zebras) animals are particularly susceptible to the disease.

The tsetse fly – found exclusively in Africa’s tropical lowlands – had a great, and often hidden, impact on settlement and productivity in Africa. The disease discouraged cattle keeping in endemic areas, which meant that communities living in those areas practiced a much less intensive form of agriculture, because of the lower likelihood of using oxen – or the plough – in farms.

The ripple effects of that were extensive. First, due to not having large animals at their disposal to do the heavy agricultural work, communities living in endemic areas are associated with lower population densities, and a greater demand for human labour, including slavery, to make up for the labour shortfall.

It helped elevate the status of cattle-keepers, creating a class system in some cases. In parts of Uganda and Rwanda, for example, cattle-keepers formed a kind of aristocracy over the farming class.

Without the plough and oxen, women were also more likely to be doing farm work. Controlling a plough and big animals requires considerable physical strength, which men have a comparative advantage in. But if the agriculture is just using sticks and hoes, there’s really no physical difference between men and women on the farm.


When humans started a settled way of life, eating mostly grain and vegetables, one commodity shot up in demand and value – salt. For those who mainly hunt and eat roasted meat, they are able to get natural salt from meat. But plants are deficient in salt, and with diets switching to domesticated crops, adding salt to food became an absolute necessity for maintaining life.

In fact, throughout history, salt has been a central commodity in human trade, because people feared a lack of salt the way people in the industrialised world today fear a shortage of fuel oil, says this article in the Smithsonian Magazine. In fact, the word “salary” has it roots in the Latin salarium, derived from sal (salt). 

Gold has always been a major player in trade.

In West Africa, gold was abundant in the south, and salt in the desert north. So powerful empires such as Ghana, Mali and Songhai arose around the salt trade, organised along long-distance trade routes. Camel caravans from North Africa carried bars of salt as well as cloth, tobacco, and metal tools across the Sahara to trading centers like Djenne and Timbuktu on the Niger River. The salt was traded for gold, ivory, slaves, skins, kola nuts, pepper, and sugar.

In East Africa too, the salt mines in western Uganda were a key component of the Bunyoro kingdom’s regional importance in the pre-colonial period ; the kingdom controlled the lucrative salt works of Kibiro, Lake Albert.


Maize is the staple crop in eastern and southern Africa, where it forms the centre of stiff porridges that are the mainstay of food cultures in the region, known by various names – ugali (Kenya), sima (Kenya/ Tanzania), nshima (Zambia/ Malawi), posho (Uganda), sadza (Zimbabwe) and pap (South Africa).

But maize isn’t indigenous to Africa. It was introduced in the sixteenth century from South America either by the Portuguese or by trans-Saharan Arab traders. Maize proved popular as it gave higher yields, was less prone to bird damage, and contained much more carbohydrates per gram (79g) than other indigenous starches, such as yam (28g) or plantain (32g). It also stored much better.

It enabled population expansion, but its high calories per gram, and good storage capability, quickly gave it a much darker use. The Portuguese required cheap, storable, and local food sources to support the slave trade, and maize served this need, becoming the principal food of slave ships, and ultimately, enabling the Trans-Atlantic slave trade.

Maize exports also helped entrench the dominance of empires that grew it in West Africa, such as the Ashanti in Ghana.


Maize is the dominant crop in eastern and southern Africa, with an important exception – Uganda. Uganda is the world’s second largest producer of bananas after India. More than 75% of all farmers grow bananas; depending on the region, domestic per capita consumption is estimated between 220-460kg, the largest in the world, mainly cooking bananas that were domesticated in the Great Lakes region.

Bananas are not as energy dense as maize, containing only about a third of the calories of maize per gram. They are lower in protein and fat as well.

But the trade off is that bananas, unlike grain crops, are in season all year round. There is no lean time of the year, and getting today’s dinner often means little more than going into the back garden and chopping some down. That means fewer worries about where the next meal will come from.

That predictability of food had two important impacts in Ugandan history – it is cited as one of the factors that enabled the Buganda kingdom to raise and support a standing army, and dominate its neighbours, who were growing mainly sorghum or millet.

In the modern era, Uganda’s food security saw the country through decades of repression, dictatorship and civil war in the 1970s and 1980s, without suffering famine or starvation that may have been the case if the staple crop was seasonal.

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