It was all very Game of Thrones, only instead of a frosty wall holding back an army of the dead, this ice blocked some of the tributaries that would normally flow to the Columbia River. Periodically, though, that water would break through, releasing the equivalent of one of the smaller Great Lakes. “So it caused these catastrophic floods to surge across the landscape in the interior Northwest,” says Davis. In what we now call Cooper’s Ferry, in western Idaho, humans were fortunate enough to live along a river running above that flood plain. They were also fortunate enough to share the landscape with a menagerie of game, including now-extinct species: mammoths and native species of horses, and perhaps even camels. “It was a very different world than what we know now,” says Davis. “We don’t find really a lot of archaeological evidence for other kinds of activities, like fishing or plant use. That doesn’t mean they weren’t doing it—we just haven’t seen it yet. But I imagine hunting was very, very important.” That’s because Davis and his colleagues have turned up amazing artifacts on traditional Nez Perce land at Cooper’s Ferry: 14 weapons called projectile points, which the researchers described last month in the journal Science Advances. The term “projectile points” means weapon tips that have been sharpened by human hands, like arrowheads or the heads of darts or spears. By radiocarbon-dating animal bones that were mixed in with the points, they landed at an average age of nearly 16,000 years, the oldest projectile points discovered so far in the Americas. “Technology is one of the main hallmarks of being human, and to be able to measure that in the archaeological past is really important,” says Davis. “Looking at the patterns and designs, and how they’re manufactured by sort of deconstructing the geometry of them, we can start to get in the heads of people and see the ways that they were thinking about technological schools of thought: How can we turn a block of rock into something useful that can feed us?” Below, you can see outlines of the original extent of each point. The points are only half an inch to 2 inches long, but they’re menacingly sharp, likely shaped by using the tip of an antler to apply pressure and squeeze off stone flakes. The lower bits of the points are “stemmed” in a rectangular shape, so they could have been attached to a wooden shaft, maybe 4 or 5 feet long, to make a dart. How much damage could an inch-long projectile point have actually done to the sizable game of North America? A lot, as it happens, because these people probably used a spear-thrower, a special hook-like tool that provided extra leverage to propel the dart with much more force than chucking by hand alone. Combining the sharp tips with the weight of the wooden shaft would have given each one a lot of penetrative power. “This is translating all that energy into a very, very, very small point of impact,” says Davis. “Thus you can penetrate very deeply. And that’s really the whole purpose of this, is to get a very sharp object inside the animal and cause the cardiovascular system to fail. You really need to just poke holes in the system.” These projectile points were essentially prehistoric armor-piercing bullets, capable of inflicting gnarly internal trauma. A direct hit to the heart could drop an animal dead. Puncturing other organs and causing internal bleeding might take longer, but the hunter would just follow their prey until it collapsed, the way a modern hunter with a rifle might do. Even though these projectile points wouldn’t have been as durable as chunkier tips that archaeologists have also found in the Americas, they’d take less material and time to produce. “You might not be able to resharpen them as many times, but you can just make another one really fast,” Davis says. “So it’s two different concepts of how to approach weapon technology.” Intriguingly, these points from Cooper’s Ferry resemble others found in Japan from around the same time period. That may help shed light on an ongoing debate in the scientific community about the peopling of the Americas: when exactly people got here, and how they did so. Over the past few decades, archeological discovery after discovery has pushed back the timeline of human habitation of the Americas. Previously, the thinking went that Clovis people (so named because of artifacts found in Clovis, New Mexico) crossed from Siberia to North America by foot as ice melted around 12,000 years ago. But archaeologists have been finding “pre-Clovis” artifacts all across the Americas—in Texas, Florida, Chile, and Peru—dating to 13,000, 14,000, or 15,000 years ago. If these projectile points are 16,000 years old, they were made when northern stretches of America were still locked in ice. And that, Davis thinks, makes it unlikely that people made a southward journey by foot through the interior. “There’s so much ice at the time that there’s no opening in the interior to move from north to south,” says Davis. “So we have people at the Cooper’s Ferry site south of the ice sheets 16,000 years ago—they had to get there somehow.” But this scenario presents some archeological challenges: First, there aren’t any boat artifacts from this period that’d suggest people had the technology to get from Asia to the Americas by sea. (That’s not to say the boats didn’t exist. Humans got from Asia to Australia 60,000 years ago, Davis says, which would presumably require long-range boating.) And as the world transitioned into the warmer climate we enjoy today, all that ice melted and drove up sea levels, shifting the Pacific coastline and submerging any potential artifacts. Why exactly people would have made the journey is also an open question—and perhaps an unanswerable one. “It’s hard to know what motivated people to make that move from Northeastern Asia to Northwestern North America,” says Smith. “Those areas were connected by land, so it wasn’t like people said, ‘OK, we’re getting in this boat and we’ll never see you again.’” Instead, it could have been much more of an organic, slow process in which people crept down the Pacific coastline, maintaining contact with Asian communities. Davis and his colleagues don’t know if the groups from Japan and the Americas were genetically related—they don’t have the genetic material to actually back up such a theory. But the similarity of the projectile points each group produced could suggest a sort of ancient social network, the sharing of technology. “It doesn’t matter, necessarily, if their genetics are the same,” says Davis. “You meet somebody from some other part of the world and you’re holding an iPhone, you have the same technology as that person—it doesn’t mean you’re genetically related.” It would make sense that as humans flowed from Asia to the Americas, they’d use similar projectile points. “By bringing in the northern Japan connection, we’ve got a pretty good hypothesis about linking up Old and New World assemblages in a comparable time period,” says David Hurst Thomas, senior curator in residence of North American archaeology at the American Museum of Natural History, who wasn’t involved in the research. It’s an early theory that’ll need critiquing and further evidence, he adds, “but I think it’s groundbreaking.” Davis also thinks this may not have been a singular connection between Asia and the Americas during that time period. Perhaps after these people brought the knowledge of the projectile points with them on their journey, other groups kept coming, keeping the ocean-spanning technological network alive—adding more intriguing wrinkles to the enormously complicated history of the peopling of the Americas. “It’s hard to know much about how such a network operated over time and space with only two far-apart data points,” says Davis of the artifacts discovered in Japan and Idaho. “But it’s a place to start.”
