- Previously it was thought the 'Clovis culture' introduced the first hunters on that continent, some 1,000 years later via a land bridge from Siberia
- Scientists get the age from carbon-dating, 30 years after the rib was found in the U.S. state of Washington
An ancient spear lodged in a mastodon has proved humans populated North America 1,000 years earlier than previously thought, it was claimed today.
Scientists have now accurately carbon-dated the sharp tip, itself carved from mastodon bone, 30 years after it was found in the U.S. state of Washington.
It was embedded in a rib from one of the creatures, a giant relative of the elephant and woolly mammoth, and after a long wait experts have said that the bone and spear point are both around 13,800 years old.
Breakthrough: This picture shows the rib fragment with the embedded spear, which proves that human hunters populated North America 1,000 years earlier than previously thought
They managed to set this date by analysing collagen protein from the rib and DNA from the same bone and the spear.
Previously the first indications of mastodon hunting were associated with the 'Clovis culture' which emerged some 1,000 years later.
The Clovis people were believed to be the first to colonise North America after emigrating from Asia, and are said to be the ancestors of all present day Native American tribes.
Study: The position of the ribs from the Mastodon's skeleton are marked on this diagram, one of which was pierced by a spear
Their thirst for hunting is blamed by some experts for the sudden disappearance of mammoths, mastodons and other large 'megafauna' mammals from the continent.
But it appears there were other humans doing the same thing hundreds of years earlier.
Professor Eske Willerslev, from the University of Copenhagen in Denmark, who led the research, said: 'It is proof that humans have been present in north America for longer than previously believed.
'The 'Clovis First' theory, which many scientists swore to just a few years back, has finally been buried with the conclusions of this study.
The rib from various angles: A) Closeup view. (B) Reconstruction showing the bone point with the broken tip. The thin layer represents the exterior of the rib. (C) CT X-ray showing the long shaft of the point from the exterior to the interior of the rib. (D) The entire rib fragment with the embedded bone projectile point
'Our research now shows that other hunters were present at least 1,000 years prior to the Clovis culture. Therefore, it was not a sudden war or a quick slaughtering of the mastodons by the Clovis culture, which made the species disappear.
'We can now conclude that the hunt for the animals stretched out over a much longer period of time. At this time, however, we do not know if it was the man-made hunt for the mastodons, mammoths and other large animals from the so-called megafauna, which caused them to become extinct and disappear.
'Maybe the reason was something completely different, for instance the climate.'
The rib containing the spear point was part of a collection of mastodon remains unearthed in the late 1970s.
Image: An artist's impression of what a mastodon would have looked like, based on the skeletons found across the world
Giant: How the 10ft tall mastodon may have looked next to a comparatively tall 6ft man
Since then experts have argued over its age.
The new research, reported in the journal Science, used cutting edge technology to date carbon samples from the bone, the spearpoint and a pair of tusks from the same fossil site.
Scientists also carried out CT X-ray scans to visualise the hidden part of the spear tip embedded in the bone.
The point was found to be at least 27 centimetres long, comparable to the length of later Clovis-age weapon heads.
Hulking: A replica of a Mastodon skeleton towers over a group looking at it in America