How long ago were dogs domesticated from wolves?

At least 15,000 years, and quite possibly over 30,000 - which puts it before agriculture, before pottery, before permanent settlements. Dogs were domesticated by hunter-gatherers, and they are the only animal we took on before we had anything to keep them for except company and work.

The likely mechanism is self-selection rather than capture. Wolves that could tolerate being near humans got access to scraps around camps; tolerance was heritable; and over generations the tolerant population diverged. A long-running Russian experiment breeding silver foxes purely for friendliness produced, within a few decades, animals with floppy ears, curly tails, piebald coats and shorter snouts - traits nobody selected for, which appear to come bundled with tameness.

Where and how often it happened is not settled. Genetic studies have supported a single origin and a double one, in Europe and in Asia, and the argument continues. What is clear is that dogs read us in a way no other animal does: they follow human pointing and eye direction from puppyhood without training, which wolves raised identically do not, and chimpanzees largely fail at.