Archaeologists discover key tool that helped early Americans survive the ice age

(CNN) — Tiny artifacts unearthed at a Wyoming site where a mammoth was butchered 13,000 years ago are revealing intriguing details about how the earliest Americans survived the last ice age.

Archaeologists found 32 needle fragments made from animal bone buried almost 15 feet (nearly 5 meters) underground at the La Prele site in Converse County. They are not the earliest eyed needles in the archaeological record, but for the first time scientists have been able to identify what the needles were made of by analyzing protein information contained in the bone collagen. The results were not what they expected.

“We had assumed they would be made out of bison or mammoth bone, which comprise most of the animal bones found at La Prele and other sites of its age in the High Plains and Rocky Mountains of North America,” said Wyoming state archaeologist Spencer Pelton, lead author of a new study on the needles published November 27 in the scientific journal PLOS ONE.

Instead, the needles were created from the bones of red foxes, bobcats, mountain lions, lynx, the now-extinct American cheetah, and hares or rabbits, the study found.

“It was extremely surprising that these needles were made out of small carnivores,” Pelton said.

The scientists reached their conclusions by extracting collagen from the artifacts and analyzing its chemical composition, specifically short chains of amino acids known as peptides, and then comparing those results with peptide data from animals known to have existed during that period in North America. It’s a technique known as zooarchaeology by mass spectrometry, or ZooMS.

The La Prele Mammoth site was discovered in 1986, and archaeologists believe a group of prehistoric people either killed or scavenged a young mammoth there, setting up a temporary camp to process its carcass. Given the age of the site and some distinctive artifacts, the people who camped out at La Prele were likely from the Clovis culture, one of North America’s oldest known human populations.

Needle in a haystack

Finding the tiny needles required a thorough and precise excavation, Pelton said. The team identified concentrations of buried artifacts by digging multiple test pits 1 square meter (10.8 square feet) in size until they identified relatively dense concentrations of artifacts. Larger excavations of 25 to 30 square meters (270 to 323 square feet), revealed the floors of dozens of temporary dwellings.

However, the team found the needles only when they used 1/16th-inch (1.6-millimeter) fine screen mesh to sift the excavated sediment.

“Relatively few archaeological sites are excavated with this level of precision, so it’s possible that bone needles have been missed during previous excavations at other sites,” Pelton said.

Prehistoric people occupied the site toward the end of the last ice age, and temperatures would have been 5 to 7 degrees Celsius colder than they are today, Pelton said.

To survive such low temperatures, humans likely created tailored garments with closely stitched seams to protect against the elements. However, clothing is perishable and all but invisible in the archaeological record for this period, save for the needles that produced the garments.

“This sort of climate would have required pretty robust, tailored parkas of the sort produced by the historic Inuit,” Pelton said. “It would have likely incorporated fur fringes around the sleeves and hood, which is why we think people were trapping animals like foxes, cats and hares in the first place.”

Before the invention of needles, humans likely wore looser, draped clothing made using pointed tools called awls, which created more widely spaced and coarsely perforated seams, the study noted. Needles also made it possible to decorate clothes, and the oldest bead, made from hare bone, found in the Americas was previously discovered at the same site.

For thread, early Americans likely used the sinew from the connective tissues of large mammals, Pelton said.

Evidence of animal trapping

Foxes and wild cats are difficult to kill using traditional hunting tools such as spears, so Pelton suspects Stone Age hunters caught the small carnivores with traps, although direct evidence of animal trapping hasn’t been found at sites of this age in North America.

It makes sense that early humans would use the small, thin paw bones of dogs, cats and hares to make needles, said Ian Gilligan, an honorary associate in the discipline of archaeology at the University of Sydney in Australia. He wasn’t involved in the research but authored a recent study on the development of eyed needles.

“These distal limb and paw bones are generally the right size and shape and need relatively little work to turn them into needles, mainly sharpening one end and drilling a hole in the opposite end,” he explained.

“Other bones from these animals are either thicker or not as straight, and comparable bones from larger animals like bison would require more work to turn into needles,” he added. “For hunter-gatherers, crafting needles to sew tailored clothes is a time-consuming task, so any strategy that makes the manufacture of needles more efficient will have survival advantages.”

Once equipped with warm, close-fitting garments, humans had the capacity to expand their range to places from which they were previously excluded due to the threat of hypothermia or death from exposure, according to the study, making eyed needles an extremely important prehistoric innovation.

It is “no coincidence” that needles are found at the oldest sites in North America — the continent was likely unoccupied until humans had the ability to make tailored clothes, Gilligan noted.

“Regardless of how good they were as hunter-gatherers, humans could never push into regions like northern Siberia without sophisticated clothes,” Gilligan said.

“Without needles, humans could not walk across the land bridge between Siberia and North America, a dry corridor that was exposed by low sea levels as the climate became colder toward the end of the last ice age,” he added.

Gilligan said the needles discovered at the Wyoming site are smaller and more delicate but otherwise similar to the world’s oldest needles, used in Siberia 40,000 years ago and in northern China 35,000 to 30,000 years ago.

“Compared to loose garments like capes and cloaks, tailored clothes offer better protection from wind chill … Needles would also be useful for sewing the inner layers in multilayered garment assemblages, which provide added thermal insulation — the beginning of underwear,” he said.

The research adds to a growing body of research suggesting that hunting strategies among hunter-gatherers were “not always about getting food.”

“Some of the major technological innovations and trends in human prehistory may relate to clothes rather than food,” Gilligan said, “and the invention of needles is perhaps just one example.”

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