When archaeologists speak of a "secondary products revolution" (sometimes abbreviated SPR), they refer to the revolutionary changes in the strategies that occurred in human relationships with animals and plants. The earliest relationships we humans have with animals and plants is simply hunting for them and eating the nutritious parts. The primary step forward of animal and plant domestication likely did not alter that relationship much, except to make both plants and animals more easily accessible, and thus a much more reliable source of food.
However, at some point after plant and animal domestication of the Neolithic period, or so the theory goes, humans shifted their plant and animal exploitation to other qualities, qualities that didn't necessarily involve killing the animal. Humans recognized that milk and blood could be used to make a variety of foods, some of which could be stored for long periods. Wool and plant fiber could be used to make cloth, netting, baskets and even structures: all of these were likely among the first products that we humans exploited from animals and plants. Using animals to draft plows, sledges and wheeled carts came later.
By expanding the kinds of ways we used plants and animals, these strategies also altered our thinking and the general evolution of how we obtain food and continue to live today.
SPR in Theory
The scholars Vere Gordon Childe and Andrew Sherratt initially proposed the SPR theory, and argued that the widening of exploitation into secondary products occurred well after primary domestication of animals such as goats, sheep, cattle and camels; and wheat, barley and rice.
While Childe and Sherratt are the two scholars most associated with the theory, they never directly tested the idea against real data. The first major test of the theory was by Haskel Greenfield, who through the analysis of animal bones from SE European sites discovered that there were significant changes in domestic animal exploitation strategies coincident with the beginning of the post-Neolithic (3300 BC - Chalcolithic and Bronze Age) that indicated sheep, goats and cattle were being exploited for the first time for both their primary and secondary products on a larger scale.
More recently, archaeological investigations seem to push back the date of the use of secondary products, making the SPR closer to the original domestication period. Nevertheless, the leap between meat-eater and cart-puller is still considered an evolutionary step forward.
SourcesThanks to Haskel Greenfield for assistance with this entry.
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