Agrarian society
Agrarian society were preceded by hunter and gatherer and horticultural societies and transition into industrial society. The transition to agriculture, called the Neolithic Revolution, has taken place independently multiple times. Horticulture and agriculture as types of subsistence developed among humans somewhere between 10,000 and 8,000 years ago in the Fertile Crescent region of the Middle East. The reasons for the development of agriculture are debated but may have included climate change, and the accumulation of food surplus for competitive gift-giving. Most certainly there was a gradual transition from hunter-gatherer to agricultural economies after a lengthy period when some crops were deliberately planted and other foods were gathered from the wild. In addition to the emergence of farming in the Fertile Crescent, agriculture appeared in: by at least 6,800 B.C.E. in East Asia (rice) and, later, in Central and South America (maize and squash). Small-scale agriculture also likely arose independently in early Neolithic contexts in India (rice) and Southeast Asia (taro). However, full dependency on domestic crops and animals, when wild resources contributed a nutritionally insignificant component to the diet, did not occur until the Bronze Age.
East Africa
The southern part of East Africa was occupied until recent times by Khoisan hunter-gatherers, whereas in the Ethiopian Highlands the donkey and such crop plants as teff allowed the beginning of agriculture around 7,000 B.C. Lowland barriers and diseases carried by the tsetse fly, however, prevented the donkey and agriculture from spreading southwards. Only in quite recent times has agriculture spread to the more humid regions south of the equator, through the spread of cattle, sheep and crops such as millet. Language distributions suggest that this most likely occurred from Sudan into the African Great Lakes region, since the Nilotic languages spoken by these pre-Bantu farmers have their closest relatives in the middle Nile basin.