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Jun 16th, 2024
Why Did Early Humans Prefer to Hunt Near Water Sources?

Elephant Hunting and Stone Quarries in the Paleolithic Era

  • Humanities
  • Archeology

Archaeologists from Tel Aviv University have uncovered the mystery surrounding extensive Paleolithic stone quarrying and tool-making sites: Why did Homo erectus repeatedly revisit the very same locations for hundreds of thousands of years? The answer lies in the migration routes of elephants, which they hunted and dismembered using flint tools crafted at these quarrying sites.


The research was led by Dr. Meir Finkel and Prof. Ran Barkai of Tel Aviv University’s Jacob M. Alkow Department of Archaeology and Ancient Near Eastern Cultures. The study was published in the journal Archaeologies.


Prof. Ran Barkai.


Prof. Ran Barkai explains: “Ancient humans required three things: water, food, and stone. While water and food are necessities for all creatures, humans relied on stone tools to hunt and butcher animals, as they lacked the sharp claws or fangs of other predators. The question is, why do we find rock outcrops that were used for the production of flint tools, surrounded by thousands of stone tools, and next to them rock outcrops containing flint that was not used for the production of tools? A study of indigenous groups that lived until recently, with some still alive today, shows that hunter-gatherers attribute great importance to the source of the stone — the quarry itself — imbuing it with potency and sanctity, and hence also spiritual worship. People have been making pilgrimages to such sites for generations upon generations, leaving offerings at the rock outcrop, while adjacent outcrops, equally suitable for stone tool production, remain untouched. We sought to understand why; what is special about these sites?”


How did elephant migration routes affect prehistoric quarry locations?

For nearly 20 years, Prof. Barkai and his colleagues have been researching flint quarrying and tool-making sites in the Upper Galilee. These sites are characterized by large nodules of flint convenient for crafting and are located within walking distance of the major Paleolithic sites of the Hula Valley — Gesher Benot Ya’akov and Ma’ayan Baruch. These sites boast thousands of quarrying and extraction localities where, until half a million years ago, in the Lower Paleolithic period, prehistoric humans fashioned tools and left offerings, despite the presence of flint in other geological formations in various places. Because elephants were the primary dietary component for these early humans, the Tel Aviv University researchers cross-referenced the database of the sites’ distribution with the database of the elephants’ migration routes and discovered that the flint quarrying and knapping sites were situated in rock outcrops near the elephants’ migration paths.


“An elephant consumes 400 liters of water a day on average, and that’s why it has fixed movement paths,” says Dr. Finkel. “These are animals that rely on a daily supply of water, and therefore on water sources — the banks of lakes, rivers and streams. In many instances, we discover elephant hunting and processing sites at “necessary crossings” — where a stream or river passes through a steep mountain pass, or when a path along a lakeshore is limited to the space between the shore and a mountain range. At the same time, given the absence of available means of preservation and the presence of predatory animals in the area, the window of opportunity for a group of hunter-gatherers to exhaust their elephant prey was limited. Therefore, it was imperative to prepare suitable cutting tools in large quantities in advance and nearby. For this reason, we find quarrying and knapping sites in the Upper Galilee located a short distance from elephant butchering sites, which are positioned along the elephants’ movement paths.”


Quarries and flint piles in the Galilee (Photo: Meir Finkel).


Subsequently, the researchers sought to apply an adapted model from the one they developed in Israel to several sites from the Lower Paleolithic period in Asia, Europe and Africa, where such a “triad” exists. These included both sites where the hunted animals were elephants or mammoths, as well as later sites where other animals, such as hippos, camels, and horses, were the prey.


"It appears that the Paleolithic holy trinity holds true universally: Wherever there was water, there were elephants, and wherever there were elephants, humans had to find suitable rock outcrops to quarry stone and make tools in order to hunt and butcher their favorite megaherbivores", says Prof. Barkai.


"It was a tradition: For hundreds of thousands of years, the elephants wandered along the same route, while humans produced stone tools nearby. Ultimately, those elephants became extinct, and the world changed forever" - Prof. Barkai.


Jun 9th, 2024
How Did Researchers Create a Memory-Retaining Metamaterial?

Memory Metamaterial 'Chaco' Transforms Computing

  • Engineering

Researchers from Tel Aviv University and Los Alamos National Laboratory have developed a novel mechanical metamaterial that remembers the order of actions performed on it, much like a computer following a sequence of instructions. Unlike ordinary materials that respond in the same way to a sequence of external manipulations regardless of their order, the new metamaterial – named ‘Chaco’ after the archaeological site of Chaco Canyon in New Mexico – exhibits history-dependent behavior, thus opening a pathway to exciting applications in memory storage, robotics, and even mechanical computing.


The research was led by Chaviva Sirote-Katz, Dor Shohat, Dr. Carl Merrigan, Prof. Yoav Lahini and Prof. Yair Shokef from Tel Aviv University, and Dr. Cristiano Nisoli from Los Alamos National Laboratory.



What Makes This Metamaterial So Unique?

A metamaterial is a designed structure made of building blocks that are much larger than atoms or molecules. The metamaterial’s physical properties are set mainly by the spatial arrangement of these blocks. This research focuses on a mechanical metamaterial comprised of an array of flexible beams that easily bend under compression. To obtain unique properties, the researchers built a metamaterial with innate frustration – namely with a geometric arrangement of the beams that do not allow all beams to simultaneously respond to external pressure the way each beam would like. "This material is like a mechanical memory storage device that can remember a sequence of inputs", explains Dor Shohat, a Ph.D. student at TAU who took part in the research.


"Each of its mechanical building blocks has two stable states, just like a single bit of memory", Shohat explained.


The secret behind Chaco’s memory lies in its unique design inspired by the concept of frustration found in magnetic systems, which are known for their memory properties. Similar to how geometric frustration can prevent magnets from reaching a simple, ordered state, Chaco's building blocks are arranged in a way that prevents them from easily settling into an ordered, low-energy configuration. This controlled frustration creates a multitude of possible states of property, which allow the material to remember the sequence of actions it has experienced. "By carefully designing the geometry of the material, we can control the way it responds to external forces", adds Chaviva Sirote-Katz, another Ph.D. student involved in the research.


"This allows us to create disorder and complex behaviors in a simple, ordered structure", Sirote-Katz adds.



Encoding Information in Chaco

Chaco's ability to recognize sequences of actions is based on its non-Abelian nature, meaning the order of operations matters. For example, flipping two units within the material in one order may lead to a different final state than flipping them in the reverse order. This sensitivity to history allowed the researchers to encode information in the sequence of actions and later retrieve it simply by observing the final state of the material.


The study, published in Nature Communications, effectively links the realms of magnetism and mechanics. As magnetic materials exhibit a manifold of exotic behaviors generally not found in mechanical ones, the design recipe behind Chaco offers transportable novel design principles for mechanical materials with remarkable properties and functionalities. The research team posits that developing these principles will enable the creation of 'smart' materials with inherent memory and the ability to perform computations.

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