HUMAN beings have spent most of their time on the planet as
hunter-gatherers. From at least 85,000 years ago to the birth of
agriculture around 73,000 years later, they combined hunted meat
with gathered veg. Some people, such as those on North Sentinel
Island in the Andaman Sea, still do. The Sentinelese are the
only hunter-gatherers who still resist contact with the outside
world. Fine-looking specimens—strong, slim, fit, black and stark
naked except for a small plant-fibre belt round the waist—they
are the very model of the noble savage. Genetics suggests that
indigenous Andaman islanders have been isolated since the very
first expansion out of Africa more than 60,000 years ago.  About
12,000 years ago people embarked on an experiment called
agriculture and some say that they, and their planet, have never
recovered. Farming brought a population explosion, protein and
vitamin deficiency, new diseases and deforestation. Human height
actually shrank by nearly six inches after the first adoption of
crops in th