domestication-syndrome

Dogs diverged from wolves at least 15,000 years ago — possibly 40,000 years ago — and the transformation involved not just behavioral tameness but a cascade of physical changes no one selected for: floppy ears, piebald coats, shortened snouts, reduced brain volume. The same cluster of traits appears in domesticated cattle, pigs, horses, and foxes bred in a 60-year Russian experiment. This pattern has a name, a mechanistic explanation, and implications for understanding a transition that reshaped the human species.