In his book "Africa: A Biography of the Continent", John Reader writes that
a) the prevalence of diseases and parasites that had evolved alongside humans prevented sub-saharan Africans from concentrating in large numbers to form dense cities until quite recently in history. One striking example he gives is the tsetse fly, whose vast territory prevented agricultural expansion.
and
b) that elephants were a major problem for subsistence farmers compounding problems of labour shortage and the arduous farming environment. Farming activity would attract raiding elephants and farmers were only able to hold them off if they lived in together in larger enough group.
Both these factors were major constraints on the population growth of Africa. It sounds intuitively right but is it just a just-so story?
I can't address the merit of John Reader's theory, especially if he says "Africa" rather than a more specific part, and I also haven't read the book so I'm taking it out of context, but I can provide an example of another way of looking at the question. Ultimately, the question is, was agriculture possible in the regions his theory covers?
“Why did agricultural revolutions erupt in the Middle East, China and Central America but not in Australia, Alaska or South Africa? The reason is simple: most species of plants and animals can’t be domesticated. Sapiens could dig up delicious truffles and hunt down woolly mammoths, but domesticating either species was out of the question. The fungi were far too elusive, the giant beasts too ferocious. Of the thousands of species that our ancestors hunted and gathered, only a few were suitable candidates for farming and herding. Those few species lived in particular places, and those are the places where agricultural revolutions occurred.”
Excerpt From: Yuval Noah Harari. “Sapiens.”
Agriculture did develop independently in West Africa in ~3000 BC, but the reasons why it didn't 'take' like it did elsewhere are more complex. The forces that shape the direction of a society over a few thousand years are numerous and intertwined; to simplify it to elephants and parasites makes good conversation but it's far too simplified for a proper understanding of the matter.
I'm not an expert on the matter, but I strongly recommend the book I quoted if you want a more macro-historical view of the forces that shape our species, and you can come to your own conclusions on the matter.
To point A, I presume you are referring to the following section of text from page 254^1:
While the out-of-Africa population soared from just hundreds (around 100,000 years ago) to 200 million (by 0 A.D.), and rose to just over 300 million in the next 1500 years, the African population increased from 1 million to no more than 20 million 100,000 years later (by 0 A.D.), and to only 47 million in A.D. 1500. . . . By leaving the tropical environments of the cradle-land in which humanity had evolved . . . [human groups who moved to Eurasia] also left behind the many parasites and disease organisms that had evolved in parallel with the human species. . . . Out of Africa, beyond the reach of the insects and organisms which had reinfected generation after generation, the multiplication of human numbers quickly assumed a hitherto unprecedented scale. . . . Meanwhile, contemporary populations in the tropical African cradle-land remained constrained by debility and disease. . . . It explains why the rise of indigenous cities and civilizations in Africa had hardly begun when the migrants returned with foreign ideas of how it should be done.
So, let us do a little bit of basic arithmetic, using the estimates that Reader provides to us.
| year | outside Pop | African pop | africa as % of rest of world pop. |
|---|---|---|---|
| 100,000 bc | "hundreds" | 1,000,000 | 99.99% |
| 0 BC | 200,000,000 | 20,000,000 | 10% |
| 1500 AD | 300,000,000 | 47,000,000 | 16% |
So, Reader's narrative of the population of the rest of the world expanding wildly while African populations remain limited only really fits from the period from 100,000 BC to 0 BC. For the next 1500 years, the population of Africa grows to become a larger portion of the Rest of World population. So, His own estimates do not agree with the picture he is trying to paint.
It explains why the rise of indigenous cities and civilizations in Africa had hardly begun when the migrants returned with foreign ideas of how it should be done.
Frankly, this reeks of the Hegelian notion that Africa had no history until Europeans arrived. Inconveniently for Reader, it is just as incorrect.
By 1200 AD, cities with populations over 20,000 were widespread in Africa, in areas ranging from the Nile Valley and the Ethiopian highlands to the West African rainforest or the Limpopo valley in what is now Zimbabwe^2
Work by Roderick and Susan McIntosh at Djenne-Djeno have traced successive periods of occupation of the site from the 3rd century bc until the 10th century AD. Comparisons of pottery fragments support the belief that successors of the early Tichitt culture may have established the first settlement at Djenne-Djenno.^3
All of this is to say, Africa has a very long history of urban settlement. In most areas,cities did not arise in africa because "migrants returned with foreign ideas of how it should be done." Rather, urbanism arose in many many areas of Africa due to local innovations or the spread of such ideas from other neighboring regions. In fairness, there are some regions where the origins of urbanism can be traced to Eurasian origins (Sabaean influences on Da'amot/Axumite urbanism; Perso-Arab influences on Swahili city-states), but those examples are not the whole story.
TL:DR- John Reader doesn't know what he is talking about in terms of African Urbanism.
1- Precolonial African Cities: Size and Density by Chapurukha Kusimba, Sibel Barut Kusimba,and Babatunde Agbaje-Williams in Urbanism in the Preindustrial World edited by Glenn R. Storey.
2 African Civilizations; an Archaeological Perspective see maps on page 13 (page 18 of the .pdf)
3- Complex Societies, Urbanism, and Trade in the Western Sahel by Kevin MacDonald. In The Oxford Handbook of African Archaeology pp 835.