rumination independently during its early
evolution in North America. Camels are well
adapted to arid climates, and were
domesticated around 2500 BCE in central Asia,
primarily as pack animals. Their milk, which
is roughly comparable to cow’s milk, is
collected in many countries, and in northeast
Africa is a staple food.
The Origins of Dairying
When and why did humans extend our
biological heritage as milk drinkers to the
cultural practice of drinking the milk of other
animals? Archaeological evidence suggests
that sheep and goats were domesticated in the
grasslands and open forest of present-day Iran
and Iraq between 8000 and 9000 BCE, a
thousand years before the far larger, fiercer
cattle. At first these animals would have been
kept for meat and skins, but the discovery of
milking was a significant advance. Dairy