Discovery in Israel Pushes Back Dawn of Agriculture to 23,000 Years Ago

Humans living in wood huts were growing grain with pesky proto-weeds 11,000 years earlier than thought, international team of scientists finds.

Moti Milrod

Evidence of cereal cultivation has been discovered at a 23,000-year-old site in the Galilee, doubling the age of the first attempts at farming.

Prehistoric man in the Levant was known to have cultivated wheat 12,000 years ago. That is believed to be roughly when the agricultural revolution began, changing society and indeed the whole planet. Cultivation is believed to predate settlement, so only its advent could foster the development of property accrual and civilization itself.

The conclusion, by an international team of archaeologists from Haifa University, Bar-Ilan University, Hebrew University and Harvard, relies on three things found on the shores of the Sea of Galilee, when it was at a particularly low point. One is a higher than expected presence of domestic-type wheat and barley, rather than the wild sort. Two is a higher than expected presence of proto-weeds that annoy farmers by growing beautifully together with crop plants. The third is the discovery of sickles and other stone tools for cutting and harvesting cereal plants.

These sickles, with flints embedded in wood and bone handles, are among the oldest ever found.

Brush huts, a grave and domestic cereal

The site was excavated for six seasons by Prof. Dani Nadel of the Zinman Institute of Archaeology at the University of Haifa. The digs exposed six brush huts, a grave, well-preserved remains of both animal and plant foods, beads from Mediterranean seashells, and stone tools.

The brush huts had evidently burned down and been rebuilt several times. If you live in a wooden hut and cook on an open fire, it isnt rare for a spark to burn down the house, observes Prof. Ehud Weiss of Bar-Ilan University.

It is rare for organic remains to be preserved so well this long. However, Weiss explains that the plant remains were unusually well-preserved because first they were charred, then covered by sediment and water, creating low-oxygen conditions unfavorable to bacteria. We see evidence of repeated sowing and harvesting of later domesticated cereals, said Weiss, head of the huge team analyzing the findings in the digs.

Remains found in the huts shows the residents of yore gathered more than 140 different species of plant, including wild emmer wheat, wild barley and wild oats.

A key indication that the grains found at the site were farmed, rather than simply existing there, is that they exhibit a telltale domesticated genetic characteristic.

Selective breeding over generations can wind up creating beings that cannot procreate without human help. The plight of domestic cereal is rather like that of some bulldog females who will die giving birth unless theres a veterinarian around to give them a caesarean.

The change from wild-type morphology to domestic-type happens when wild plants are sown repeatedly in cultivated fields, Weiss explains: Clearly the Ohalo people had been cultivating cereals for years.

Wild wheat and barley scatter their seed without trouble, as it were. When humans cultivate these grains over a number of successive seasons, however, a change occurs, says Weiss. They develop a rough scar that locks the seed dispersal units together. Such plants cannot sow themselves.

This is the hallmark of domesticated, rather than wild-type plants. These cereals were found mixed with 13 species of proto-weeds – ancient ancestors of the current weeds known to flourish in cultivated, single-crop fields – indicating that they grew together with food crops, and were unintentionally harvested together.

Prof. Marcelo Sternberg, co-author of the study and an ecologist at Tel Aviv University, argues that the findings – and the development of proto-weeds – indicate early human disturbance of the natural ecosystem.

Moreover, the prehistoric men living there were making flour. A grinding slab inside one of the huts, plus a stone tool from which microscopic cereal starch granules were extracted, provided unequivocal evidence that cereal grains were brought into the hut –- and processed into flour. Outside another hut, the researchers found flat stones that may have served in baking.

Prof. Ehud Weiss holding Iron Age grape seeds. (Credit: Faith Baginsky)

Oldest sickles in the world

Proof that the Ohalo people were harvesting lies in the sickles the archaeologists found. Analysis of the gloss along their cutting edges shows they served to reap slightly unripe cereals, Nadel says. This is another indication that the presence of a high percentage of domestic-type cereals was not random, but rather is a sign of the long-term cultivation practices of the sites residents.

Does that mean that man was farming throughout the Levant 23,000 years ago? Not necessarily. From what we see at Ohalo II, it is clear that cultivation occurred at this surprisingly early point in time, but we have no evidence that it continued in the region, Weiss says. This is why we term our findings to be evidence of trial cultivation only. Moreover, since weeds are defined by botanists as plants that developed in response to human agriculture, we call the plants that share characteristics with weeds proto-weeds.

Although full-scale agriculture did not develop until much later, the attempt had already begun, Weiss sums up. And it could have taken millennia to be accepted.

The history of technology is littered with inventions that were either not accepted by their society or simply failed, points out Prof. Ofer Bar-Yosef, a prehistorian from Harvard University. A historical example is Leonardo da Vinci, who, in his notebooks, designed several flying machines during the early 15th century. Even though da Vinci was on the right track, we had to wait until the 19th century before the Wright brothers got their first plane off the ground.