The population of Africa is far more diverse than most Americans imagine. Before Europeans arrived, Africa was already home to five major racial groups. Additionally, in millennia before 1500 CE, Africa experienced two dramatic, little-known population shifts: the Bantu expansion and the Indonesian colonization of Madagascar.

For the purposes of his book, Diamond lumps Africa’s people into five heterogeneous categories: white people in North Africa, Indonesians on Madagascar, Pygmies in the Central African rainforest, Khoisan in southern Africa, and Black people in sub-Saharan Africa—including in areas that overlap with some other races of Africans. Diamond does not go into detail about the history of white people in northern Africa because their background overlaps with that of Europe and Southwest Asia. He does, however, discuss the backgrounds of Africa’s other major racial groups.

Africa’s languages fall into five rough family groups that correspond roughly to the people who speak them. North Africans speak Afro-Asiatic languages from a family that gave rise to the Semitic languages of the Bible. Madagascar is largely occupied by people who look like and speak a language similar to the people from the island of Borneo 4,000 miles away. Black Africans and Pygmies speak primarily Niger-Congo languages, although Pygmies speak these languages with sound and vocabulary differences that suggest that their ancestors may have spoken another family of languages long ago. In several pockets on the borders between North and sub-Saharan Africa, people speak Nilo-Saharan languages. This suggests that speakers of Afro-Asiatic and Niger-Congo languages overtook much of the area that formerly belonged to Nilo-Saharan speakers. Khoisan languages are confined to the Khoisan people in southern Africa and in a few small pockets of East Africa. The existence of these pockets suggests that the Khoisan formerly covered a widespread area but were later mostly displaced by the speakers of Niger-Congo languages.

One subfamily of Nilo-Saharan languages, the Bantu languages, accounts for almost all the Nilo-Saharan languages spoken in the area archaeologists and linguists think were once inhabited by the Khoisan and Pygmies. This strongly suggests that Bantu-speaking people had some advantage that allowed them to spread outward from a single center and colonize areas where other groups formerly lived.

When Europeans arrived in Africa in the 1400s CE, Africans were growing five different sets of crops. North Africans grew most of the Fertile Crescent package. In other areas, people grew sets of crops that were more suited to their climates (see table 19.3 in the book). Three of these had crop packages that appear to have originated in Africa. In the final area, Madagascar and the southeast African coast, people grew crops such as bananas and taro, which were imported from Southeast Asia.

Africa’s archaeological record suggests that during Africa’s prehistory, people who grew crops outcompeted those who did not. In the case of Madagascar, Austronesians seem to have arrived between 300 and 800 CE. Diamond thinks these prehistoric explorers probably made it to India, from which point they followed established trade routes to Egypt and from Egypt down Africa’s eastern coast. It is also possible that they somehow sailed to Madagascar directly across the Indian Ocean. Either way, they stayed and partially displaced the original inhabitants of Madagascar.

Diamond thinks the Pygmies and Khoisan were widespread in sub-Saharan Africa before the Bantu-speaking people expanded their territory. In the case of the Pygmies, there is little archaeological evidence to support this theory. In the case of the Khoisan, however, the archaeological record is well established. It shows that the Khoisan covered a widespread area, and the Bantu moved in beginning around 3000 BCE. At that point, the Bantu were actively cultivating land and raising animals. Their expansion was slow, partly because they lost some of their animals to pests as they moved into new latitudes. Evidence suggests that they developed iron smelting techniques independently around 1000 BCE. After that, they expanded more quickly into all areas suitable for their crops throughout the subcontinent.

One area Bantu-speaking peoples did not conquer was southern Africa’s Cape, where their crop package could not easily grow. When Europeans arrived at the Cape, the Khoisan remained. European guns, germs, and steel quickly decimated the sparse Khoisan population. By the time European expansion reached the Bantu areas, however, it slowed considerably. Bantu opponents were more densely populated, inoculated against more diseases, and more technologically advanced. These factors made them more difficult to conquer.

However, European guns, literacy, and political organization ultimately enabled them to colonize the Bantu regions of southern Africa as well as much of the rest of the continent. Europeans had those advantages because Africa was unlucky in its relative lack of domesticable crops and animals. Most large African mammals are not domesticable and have never been domesticated. Africa’s smaller land area yielded fewer domesticable plants, and its north–south orientation prevented the easy spread of food production. Climate challenges resulting from latitude differences prevented the expansion of food production across the entire continent. This left a sparse hunter-gatherer population in place, which Europeans easily defeated, gaining a foothold before its long wars with the Bantu. If Europeans had not had this foothold, they may never have won in Africa at all.