THE RECORD
What changed
Cattle traction, ruminant milk and sheep fibre were adopted at different times by region, not as one simultaneous package.
EVIDENCE
What remains
Lipid residues show milk use in Southwest Asia by the seventh millennium BCE; skeletal pathologies and tools help trace traction and tillage.
WHY IT MATTERS
Why it matters
Obtaining several products from one herd reorganized seasonal labour, storage and land use.
OPEN QUESTION
Where interpretation begins
The ‘secondary products revolution’ is useful, but change was regionally uneven and evidence for the earliest ploughs remains limited.