Some 350,000 years ago, hominins – ancestors of Homo sapiens – lived in a cave of the Carmel Mountains near what is now Haifa and made primitive tools from small rocks.
This astounding archaeological find has just been announced by scientists at the University of Haifa and published in the prestigious Journal of Human Evolution. It is the earliest evidence for the use of stone tools for grinding by our human ancestors – about 150,000 years before what was previously known.
The Tabun Cave, where the tool was found, is located in the Nahal Me’arot Nature Reserve and was named by UNESCO in 2012 as having universal value. The cave was occupied intermittently during the Lower and Middle Paleolithic (500,000 to around 40,000 years ago). In the course of this period, deposits of sand, silt and clay of up to 25 meters accumulated in the cave. Excavations suggest that it is the site of one of the longest sequences of human occupation in the Levant.
The new study was written by Dr. Ron Schimelmitz, Dr. Iris Groman-Yaroslavsky, Prof. Mina Weinstein-Evron and Prof. Danny Rosenberg, from the university’s Zinman Institute of Archaeology. The rounded dolomite pebble had microscopic abrasion marks that were intentionally made and not a result of weathering or other natural changes. The object showed abrasion in a horizontal motion – from side to side, which is a motion of grinding as for food.
The unique find was unveiled as part of a new University of Haifa project in which findings from past excavations at the site are re-examined. While scanning the excavations unearthed in the cave by anthropology Prof. Arthur Jelinek of the University of Arizona in the late 1960s Schimelmitz noticed that one of the stones showed clear abrasion marks, known to exist in much later stone vessels, but not in more ancient ones.
To interpret the patterns they identified under a microscope, the researchers conducted a series of controlled grinding experiments using dolomite pebbles collected in Carmel and similar in their characteristics to pebbles from the Tabun Cave. In these experiments, different materials were worn over different amounts of time with the help of the pebbles and then immediately subjected to a microscopic examination.
“While the results did not show a perfect match between the abrasion patterns documented on the pebble and those we documented in the experimental study we conducted, we found many similarities to the abrasion marks obtained as a result of the abrasion of animal skins and other soft materials, although we don’t know exactly for what it was used,” said Groman-Yaroslavsky.
“While the tool is “simple’, seemingly, its early appearance and the fact that it has no parallel at such an early stage of human evolution give it global importance,” the researchers said. “The early emergence of grinding technology demonstrates the depth and complexity of the chain of technological innovations associated with human evolution. When did hominins start to grind food and other substances? And why? These are some of the questions that concern the researchers of human evolution.”
“”In fact, the evolution of the new grinding technology reflected in stone tools directly reflects the patterns of change in the abilities of ancient hominins to shape their environment,” added Schimelmitz. “The period some 200,000 to 400,000 years ago is one of important technological innovations and changes. In human behavior. For example, the use of fire became part of the day-to-day routine, and the use of base sites from which to go out for various activities became a way of life. In this way, grinding technology did not appear alone; it was intertwined with an array of broader change that to some extent foreshadows the complex behavior familiar to us from later civilizations – the Neanderthals and Homo sapiens.”
“Was this ability lost until it was “found” again after so many years? Although we have not been able to tie the item for food processing with certainty, it is highly probable that it was used for this. After the earliest origins of the act of grinding and how cognitive and motor abilities developed during human evolution have finally evolved into important phenomena in human culture to this day, beginning with grinding and development of food production techniques such as living permanently in one location, agriculture, storage, and later social and economic complexity,” Rosenberg concluded.