Archaeologists have uncovered projectile points used by early Americans in Idaho that are thousands of years older than any previously found in the continent.
Researchers, including those from the Oregon State University in the US, say the findings help fill gaps in the history of how early humans in the Americas crafted and used stone weapons.
The 13 full and fragmentary projectile points are razor sharp, ranging from about 1.3-5cm (0.5-2in) long, and are from roughly 15,700 years ago, according to the study, published last week in the journal Science Advances.
The projectile points are characterised by two distinct ends – one sharpened and one stemmed – as well as a symmetrical beveled shape if looked at head-on.
Researchers suspect they were likely attached to darts, rather than arrows or spears.
Scientists say the latest findings push back the evidence of such weapon use found at the site by over 2,000 years.
The latest study results throw new light on the way early Americans expressed complex thoughts through technology at that time.
“From a scientific point of view, these discoveries add very important details about what the archaeological record of the earliest peoples of the Americas looks like,” study co-author Loren Davis from OSU said in a statement.
“It’s one thing to say, ‘We think that people were here in the Americas 16,000 years ago;’ it’s another thing to measure it by finding well-made artifacts they left behind,” Dr Davis said.
The weapon tips are also “revelatory”, according to the scientists, in their similarity to projectile points found in Hokkaido, Japan, dating to 16,000-20,000 years ago.
This observation, they say, adds more detail to the hypothesis that there are early genetic and cultural connections between the ice age peoples of Northeast Asia and North America.
“The earliest peoples of North America possessed cultural knowledge that they used to survive and thrive over time. Some of this knowledge can be seen in the way people made stone tools, such as the projectile points found at the Cooper’s Ferry site,” Dr Davis said.
“By comparing these points with other sites of the same age and older, we can infer the spatial extents of social networks where this technological knowledge was shared between peoples,” he added.
Scientists say the darts, despite their small size, may have been “deadly weapons”.
“There’s an assumption that early projectile points had to be big to kill large game; however, smaller projectile points mounted on darts will penetrate deeply and cause tremendous internal damage,” Dr Davis said.
“You can hunt any animal we know about with weapons like these,” he added.
The new research also presents a picture of early human life in the Pacific Northwest.
“Finding a site where people made pits and stored complete and broken projectile points nearly 16,000 years ago gives us valuable details about the lives of our region’s earliest inhabitants,” Dr Davis explained.