During the twentieth century, the eastern Hadza comprised a nearly closed, stable, but quite rapidly increasing population. The great majority of Hadza earned their living during this time as hunter-gatherers. Even in the late twentieth century, they were getting about 95% of their food from wild animals and plants (Marlowe, 2010, p. 36). As the size of the population increased, the area inhabited decreased slightly and the number of people occupying it with other economies and other languages increased.

In the last chapter, I reported that the observations fit with predictions drawn from a stable population that has the schedules of fertility and mortality that I estimated for the Hadza. However, the 95% CI of the observations enclose levels of fertility that could be as much as 10% higher or lower, and levels of mortality that could be more than 10% lower.

Marlowe (2010, p. 256; table 10.1) described the Hadza as the median hunter-gatherer. With regard to demography, I can support the claim. At a total fertility rate (TFR) of 6.1 of births and life expectancy at birth (e0) of 32.7 years (genders combined), Hadza fertility and mortality were close to the median for hunter-gatherer populations. They demonstrate that a very normal human demography can be maintained in a predominantly hunter-gatherer economy in sub-Saharan savanna (but at a low density and small body weight).

Because Campbell and Wood (1988) and Bentley and colleagues (1993a,b) found only small differences between hunter-gatherer fertility and other traditional subsistence populations in developing countries, we can regard Hadza fertility as close to the central tendency for this wider array of ecologies. Populations described by historical demographers also overlap Hadza fertility and mortality. These include mortality of European populations before about 1800 (Laslett, 1995), Roman Egypt (Bagnall and Frier, 1994), and adult e0 in rural China AD 0 to 1749 (Zhao, 1997, table 3, average e20 was 24.0 years). Chinese families with written records between 1365 and 1849 (Yuan, 1931) also showed similar adult life expectancies. Fertility in the classic historical case of Colyton in Devon was 6.4 for married women below age 30 (Wrigley, 1966), and fertility in a variety of locations in Britain averaged 7.23 between 1600 and 1799 (Wilson, 1984). A more comprehensive set of examples can be seen in the tables in Paine and Boldsen (2006).