The Secondary Products Revolution — How Living Animals Transformed Civilization
What it is
The Secondary Products Revolution is a concept introduced by archaeologist Andrew Sherratt in a landmark 1981 paper, describing one of the most important transformations in the history of human-animal relationships. In Sherratt's framework, the initial domestication of animals (producing primary products — above all, meat) was followed several thousand years later by a fundamental shift in the way humans used domestic animals: a shift toward exploiting living animals for products that they can provide without being slaughtered — milk, wool, traction, and riding.
This shift, which Sherratt dated to approximately 4,000–3,500 BCE (though subsequent scholarship has complicated this chronology), was as consequential as the initial domestication itself.
History & domestication
Why the delay? The question of why there was a multi-thousand-year gap between initial animal domestication (approximately 10,500 BCE for sheep and goats) and the widespread adoption of dairy, wool, and traction use (approximately 4,000–3,500 BCE in Sherratt's original model) is important. Several factors likely contributed:
1. Physiological barriers to adult milk consumption. The vast majority of early human adults were lactose intolerant — lacking the enzyme lactase beyond early childhood, they would have experienced significant gastrointestinal distress from consuming significant quantities of fresh milk. The genetic mutation that produces adult lactase persistence (the ability to digest lactose throughout life) appears to have arisen and spread in the European and East African populations after the domestication of cattle and the development of dairy cultures — a clear case of cultural practice driving genetic selection. Before lactase persistence spread in a population, dairy products could still be consumed after bacterial fermentation (yogurt, cheese, kefir) reduced the lactose content through microbial conversion.
2. Woolly sheep breeds had to be developed. Early domestic sheep, as noted in the Sheep entry, had coats closer to the mouflon ancestor — not the dense, uniform, spinnable fleece of later breeds. The specific selection for woolly coats took thousands of years of directed breeding.
3. Traction technologies had to be developed. Using cattle for traction required the development of the plow, the yoke, and a cultivated understanding of how to train cattle to pull — a complex of cultural and technological knowledge that was itself a product of time and accumulation.
What the revolution produced. Once the shift to secondary products began, the consequences were enormous:
Dairy transformed the nutritional landscape of agricultural societies. Fresh milk, yogurt, cheese, and butter provided high-quality protein and fat from animals that could be milked year after year without slaughter. The dairy economy allowed farmers to maintain larger animal populations (because animals could be productive without being killed) and to produce more calories per acre than meat-only systems.
Wool created the first significant textile industry. Before wool, textiles were made primarily from plant fibers (linen, primarily) or from animal skins. Wool's extraordinary properties — warmth, fire-resistance, water-resistance, felting ability — made it far superior for cold-climate clothing, and the ability to shear a sheep repeatedly without killing it made wool a truly renewable resource. The wool trade became the economic foundation of Mediterranean and later European civilization.
Traction from cattle (and later horses and donkeys) multiplied agricultural productivity dramatically. The plow pulled by cattle could cultivate soils that hand tools could not break — the heavy clay soils of Northern Europe, for instance, that were marginal under Neolithic hand-tool agriculture became productive agricultural land when the moldboard plow and ox traction made them accessible. The spread of cattle traction is one of the reasons Northern European agricultural societies were eventually able to support such large populations.
Riding horses (and the use of donkeys, camels, and later horses as pack animals) transformed trade, communication, and warfare as described in the Horse entry.
Critiques and refinements
Sherratt's original chronology has been significantly revised. Ancient lipid residue analysis — the technique that detects milk fats in ancient pottery — has pushed the earliest dairy use back much earlier than Sherratt proposed. Pottery from sites in the Near East dating to 8,500 BCE shows milk fat residues, suggesting that dairy use began nearly simultaneously with animal domestication, not millennia later. The picture is now more one of gradual, location-specific development of secondary products use, rather than a single revolutionary transition at a specific date.
Nevertheless, Sherratt's core insight — that the shift from killing animals to living with and exploiting them changed the human-animal relationship fundamentally — remains valid and important.
Reference notes
Cross-links: Sheep (above), Cattle (above), Horse (above), all dairy entries across the Cuisinopedia, wool/textile trade connections to food culture (the same markets that traded wool traded spices and food commodities), lactase persistence entry if developed, fermented dairy entries (yogurt, kefir, cheese).
---