Israeli Archaeologists Tie Down Invention of String to More Than 120,000 Years Ago

Study of shells found in caves in northern Israel shows prehistoric humans invented string much earlier than previously thought – between 160,000 and 120,000 years ago

Ariel David
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Modern clam shell on a flax string used in experiment to detect usewear of string on shell
Modern clam shell on a flax string used in experiment to detect usewear of string on shell Credit: Iris Groman-Yaroslavski

A study of seashells collected by prehistoric cave dwellers in what is today northern Israel has indirectly pushed back the date for the invention of rope to between 160,000 and 120,000 years ago, tens of thousands of years earlier than previously thought.

Sometime between those two dates, Homo sapiens learned to twist natural fibers into a cord and began suspending perforated shells on strings to wear them as decoration, the study published Wednesday in the journal PLOS ONE concludes. 

The findings give us a clear, albeit still quite wide, timeframe for a technological development that had countless applications for prehistoric hominins, from weaving to building rafts and better hunting tools. The research into the pairing of shells and strings also opens a window into our cognitive evolution and the development of more complex behaviors and forms of communication, researchers say.

What’s even more impressive is that archaeologists figured this out without actually finding any string directly worn by our distant ancestors, since the perishable cordage has long ago decomposed in the sweltering Mideast climes.

Our story begins with a study on the microscopic patterns of wear and abrasion on perforated seashells that were found back in the 1970s in Qafzeh Cave, a site near Nazareth that was inhabited by Homo sapiens starting 120,000 years ago. The study was conducted by a team of experts led by Daniella Bar-Yosef Mayer, an archaeologist from the Steinhardt Natural History Museum at Tel Aviv University.

Holes are in fashion this millennium

The shells, some of which had been painted with red ochre, belonged to the species Glycymeris nummaria, a bivalve mollusk common throughout the Mediterranean and the northeastern Atlantic. What was particularly interesting was that the people of Qafzeh, which is 40 kilometers from the sea, had purposely brought back to the cave only naturally perforated clams – that is, shells that had developed a hole due to erosion from the sand and sea.

The researchers also compared the finds to shells unearthed at Misliya Cave, a site on Israel’s northern coast that was inhabited much earlier than Qafzeh, between 240,000 and 160,000 years ago. There archaeologists had also found a small cache of Glycymeris – but in this case the shells were whole.

Top: Whole shells, bottom: naturally perforated shells
Top: Whole shells, bottom: naturally perforated shellsCredit: Oz Rittner, The Steinhardt Museu

The study notes that if you take a walk on a beach, about 40 percent of the Glycymeris you come across will be naturally perforated, meaning that both the Misliya and Qafzeh shells were selected deliberately, not randomly. But why? The difference only made sense if the shells at Qafzeh were intended to be strung up, Bar-Yosef Mayer suspected, but the evidence just wasn’t there.

In Europe, where the climate is more conducive to the preservation of organic remains, the oldest firmly identified fragment of cord comes from a Neanderthal cave in France and dates to between 41,000 and 52,000 years ago. At Krapina Cave, in Croatia, researchers recently found an animal fiber on a 130,000-year-old eagle talon, a trophy that was commonly used by Neanderthals for decoration.

While a single fiber does not a rope make, the find does suggest that our evolutionary cousins may have also started stringing up ornaments much earlier than we had believed.

Meanwhile, Bar-Yosef Mayer set out to prove her own hypothesis on the Qafzeh shells, using a method known as use-wear analysis. This involves simulating the daily, extended use of modern-day specimens of the same kind as those found in the archaeological record and then comparing under a microscope the resulting patterns of erosion and abrasions. Contemporary shells of perforated Glycymeris were tied together on a string made with wild flax and subjected to various conditions to simulate extended wear, such as being left to dangle around in front of a ventilator or having saline solution poured on them to imitate human sweat.

Sure enough, the modern Glycymeris developed use-wear patterns consistent with those visible on the Qafzeh shells: the string produced scratches on the surface of the shell and smoothed the edges of the perforation. Other abrasions were the result of the shells banging against each other, suggesting they were worn as beads on something like a necklace or bracelet.

The use-wear analysis also showed signs of natural erosion, proving that the shells were lying on the beach for a while before they were collected, Bar-Yosef Mayer tells Haaretz. This means that they were definitely picked up solely for their ornamental value, rather than to eat the mollusk inside.

Not an Israeli start-up

Unlike the Qafzeh clams, the unperforated shells from the older site, Misliya, only showed signs of natural erosion, suggesting they were just carried back to the cave but were not suspended of manipulated in other ways. This leads Bar-Yosef Mayer and colleagues to assert that sometime between the occupation of the two caves, that is between 160,000 and 120,000 years ago, Homo sapiens started using string.

We should be careful not to conclude that rope was necessarily invented in what is today Israel, the archaeologist notes. There are multiple other caves in North and South Africa where this pattern is repeated: whole clams are found at older sites and perforated shells in more recent ones.

While she has not analyzed the finds from those caves it now seems likely that the latter groups were also suspended on strings, leaving us still in the dark as to where exactly rope made its first appearance, says Bar-Yosef Mayer.

Studying the use-wear marks shells have after dangling from a string and being blown about by a fan
Studying the use-wear marks shells have after dangling from a string and being blown about by a fanCredit: Iris Grosman-Yarus

In fact, given the above-mentioned evidence of early string in Europe, it’s hard to tell who came up with the idea first, Neanderthals or Homo sapiens, she adds.

Whoever invented rope, the new study on the early use of string and shell beads indicates that “these technologies have a much greater time depth than previously acknowledged,” says Teresa Steele, a paleoanthropologist from University of California, Davis. The use-wear analysis applied by the Israeli team opens “a window into reconstructing organic technologies that are difficult to access in deep time,” says Steele, who was not involved in the study.

Understanding the invention of rope and the use of shells as ornaments has deeper implications for our knowledge of human evolution, Bar-Yosef Mayer notes. Rope was not only essential to hang pretty things. It helped humans hunt better by creating traps and nets; it heralded the introduction of weaving, leading to improved clothing and containers; and it ultimately allowed our ancestors to build rafts and sail the seas to populate distant islands. 

Oooh, shiny!

Whether all this began with someone stringing together some beached clams, we may never know. But the change in the ornamental use of the shells between the older pattern of human behavior, at Misliya, and the more recent one, in Qafzeh, is also indicative of a transformation in the cognitive range of our ancestors.

The shells at older sites, like Misliya, were probably collected as keepsakes, says Marjolein Bosch, a zooarchaeologist from Cambridge University in Britain and an expert on the prehistoric use of mollusks.

“If you want a keepsake you will collect shells that are nice and pretty and whole,” says Bosch, who was also not part of the Israeli study. An aesthetic interest in shiny round objects, such as pebbles or shells, has been documented among prehistoric sapiens and even among earlier hominins. Marks possibly made half a million years ago by Homo erectus on a shell found in Java, Indonesia, have been dubbed the oldest engravings documented so far. 

The perforated shells of later sites like Qafzeh may have been less whole and perfect than their antecedents, but they had a much more advanced function than sitting around and just being pretty. They were meant to be displayed and communicate symbolic meaning from a distance, at a time when sapiens groups were becoming larger and venturing into vast territories beyond their African ancestral home, Bosch suggests. As humans spread around the world, such artifacts were likely important ways to recognize each other as members of the same group, cement a shared identity and perhaps, she says, even to display social status.