An excavation site near the Dead Sea in Jordan has revealed an 11,000-year-old granary, which even had elevated floors to prevent rodent pilfering and to increase air circulation.

The stone and mud building was capped with a wattle roof (branches or reeds woven around poles) was about 9.8 feet (3 meters) in diameter. The findings, reported earlier this week in Proceedings of the National Academy of Sciences, reveal wild barley as one of the ancient building's contents. Two nearby structures also appear to have been used for food and grain processing.

They were certain that the grains found at Gilgal were cultivated and not found naturally in the environment because they were found in such large quantities and because field observations showed that only moderate amounts could be gathered from natural growing sites in this part of the Jordan Valley, even in rainy years.

Although pioneer crops such as barley, lentils, rye and oats yielded satisfactory crops, early farmers faced the problem that their seeds would fall off immediately after ripening. One way to solve this problem was through domestication (causing a process by which plants would retain their seeds, rather than shedding them, to facilitate collection by farmers).

But the researchers found that not all crops were easily domesticated, causing our ancestors, the researchers maintain, to abandon certain crops (such as oats) for thousands of years, until different farmers in other parts of the world finally domesticated them.

“The most important implication of our findings is that fundamental social changes occurred before plant domestication, including the establishment of fairly permanent settlements, with communal labor and storage, based on cultivated wild plants,” Kuijt says. Researchers now generally accept that people in the Middle East and Asia must have cultivated wild plants for between 1,000 and 2,000 years, with annual harvests in the fall, before domesticated species appeared, remarks Harvard University archaeologist Ofer Bar-Yosef. “The discovery in Dhra' provides us with one of the earliest well-built examples” of a food-storage structure from before plants were domesticated, Bar-Yosef says. Storage structures there support the argument that the sowing of wild plants beginning as early as 14,000 to 15,000 years ago led to agriculture, comments archaeologist Mordechai Kislev of Bar-Ilan University in Ramat-Gan, Israel.