Paleodemography

Paleodemography is the study of human demography in antiquity and prehistory. More specifically, paleodemography looks at the changes in pre-modern populations in order to determine something about the influences on the lifespan and health of earlier peoples.

Reconstruction of ancient population sizes and dynamics are based on bioarchaeology, ancient DNA as well as inference from modern population genetics.

Skeletal analysis can also yield information such as an estimation of age at time of death. There are numerous methods that can be used, and it is best to field questions of further interest to an osteologist or bioarchaeologist. In addition to age estimation and sex estimation, someone versed in basic osteology can ascertain a minimum number of individuals (or MNI) in cluttered contexts—such as in mass graves or an ossuary. This is important, as it is not always obvious how many bodies compose the bones sitting in a heap as they are excavated.

Occasionally, disease history for things like leprosy can also be determined from bone restructuring and deterioration. While that tends to fall more under paleopathology, it is important to keep such things in mind in how they affect mortality rates.

The increasing availability of DNA sequencing since the late 1990s has allowed estimates on Paleolithic effective population sizes. Such models suggest a human effective population size of the order of 10,000 individuals for the . This includes only the breeding population that produced descendants over the long term, and the actual population may have been substantially larger (in the six digits). Sherry et al. (1997) based on Alu elements estimated a roughly constant effective population size of the order of 18,000 individuals for the population of Homo ancestral to modern humans over the past one to two million years. For the time of speciation of Homo sapiens, ca. 130,000 years ago, Sjödin et al. (2012) estimate an effective population size of the order of 10,000 to 30,000 individuals, and infer an actual "census population" of early Homo sapiens of roughly 100,000 to 300,000 individuals. The authors also note that their model disfavours the assumption of an early (pre-Out-of-Africa) population bottleneck affecting all of Homo sapiens.

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