The wild animals that hunter-gatherers hunted were not domesticated and were not available for milking.

Cheddar Man and his contemporaries had no access to dairy products as adults and no selective reason to maintain lactase production after childhood.

Second, the lactose intolerance finding is a reminder that the Mesolithic world was profoundly different from the modern world in ways that go far beyond technology.

The physiological adaptation to dairy consumption that is now widespread in northern European populations is a very recent evolutionary development, a response to a specific subsistence pattern that was introduced by Neolithic farmers and then expanded by Bronze Age pastoralists.

Cheddar Man’s body was adapted to his world — the world of the Mesolithic hunter-gatherer — in ways that would have made him physically different from his descendants not just in appearance but in physiology.