Dembitzer, J., Barkai, R., Ben-Dor, M., & Meiri, S. (2022). Levantine overkill: 1.5 million years of hunting down the body size distribution. Quat
Dembitzer, J., Barkai, R., Ben-Dor, M., & Meiri, S. (2022). Levantine overkill: 1.5 million years of hunting down the body size distribution. Quaternary Science Reviews, 276, 107316.
The authors of the study note that the mean mass 10,500 years ago was just 1.7% of the mass 1.5 million years ago. If we take the decline from around 700,000 years ago, the reduction is even more dramatic: a decline of more than 99%.
There has been some debate about what the main driver of these extinctions was. Climate change was considered to have played some role. But, over time, the evidence that hunting and habitat loss from humans was the primary driver has solidified over time.
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The average weight of early hominid species – such as neanderthals – was around 55 kilograms for females, and 65 kilograms for males.
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The archeological evidence does not allow us to say directly which animals were killed off from human hunting, and which by ‘natural causes’. Instead, researchers can measure historical changes across a range of environmental factors such as climate, temperature, rainfall, availability of vegetation, and dynamics of other species using biogeochemical markers such as isotopes. By modelling these historic changes they can assess whether any of these environmental changes coincide with changes in species populations. By process of elimination, they can then decipher the remaining contribution of human pressures.
Barkai, R., Rosell, J., Blasco, R., & Gopher, A. (2017). Fire for a reason: Barbecue at middle Pleistocene Qesem cave, Israel. Current Anthropology, 58(S16), S314-S328.
The topic of why humans started farming remains controversial. Climate is likely to have played a role: the onset of agriculture was around the time of the end of the last ice age. Before then, the climate would have been unsuitable for growing crops in many parts of the world. Still, this doesn’t explain why humans didn’t start farming during periods when the climate was stable and suitable.
One hypothesis is that humans started growing their own food because they were running out of ‘wild’ supplies. Most of the animals that were left to hunt were small. Catching enough to keep everyone going would have been time-intensive and barely sustainable. This is especially true for growing populations. Maybe humans started farming because they had no choice. They had overhunted the wild supplies and now had to create their own.
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Belfer-Cohen, A., & Goring-Morris, A. N. (2011). Becoming farmers: the inside story. Current Anthropology, 52(S4), S209-S220.
Archaeological evidence from Papua New Guinea, for example, shows that the agricultural transition was not marked by any significant changes in climate: the climate had been stable and suitable for farming for long periods of time.
Roberts, P., Gaffney, D., Lee-Thorp, J., & Summerhayes, G. (2017). Persistent tropical foraging in the highlands of terminal Pleistocene/Holocene New Guinea. Nature Ecology & Evolution, 1(3), 1-6.
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