Overview
- The team used 3D geometric morphometrics on 643 skulls spanning roughly 50,000 years, drawing on contributions from more than 40 institutions.
- By the Mesolithic and Neolithic, dogs already displayed about half of today’s cranial diversity, yet the extreme skull shapes seen in some modern breeds emerged much later with intensive 19th‑century breeding.
- Distinct dog-like cranial traits first appear in the early Holocene, with the earliest clearly domestic specimen from Veretye in northwest Russia (~10,800 years ago), and additional early dogs identified in Illinois (~8,500 years ago) and Asia (~7,500 years ago); late Pleistocene ‘proto-dogs’ do not show domesticated skull shapes.
- Quantitative signals include a detectable reduction in skull size between ~9,700–8,700 years ago, increased size variance by ~7,700 years ago, and broader shape variability from ~8,200 years onward.
- A separate Science paleogenomics study reports human–dog co-dispersal across Eurasia for at least 11,000 years, including movements linked to Early Bronze Age metalworking into western China.