- San Diego Natural History Museum Paleontologist Don Swanson pointing at a rock fragment near a piece of mastodon tusk.
- San Diego Natural History Museum
The first humans to set foot in the Americas arrived some 25,000 years ago – or so we thought.
For decades, that date has been generally accepted by scientists, though recent genetic studieshave moved the dial on that figure back by a few hundred or thousand years. But a set of new, highly controversial evidence suggests that timeline could be fundamentally incorrect.
Researchers working at an archaeological dig site that runs along the 54 freeway in San Diego, California, have uncovered what they believe is evidence of a human presence in North America that predates previous estimates by 100,000 years. They published their findings Wednesday in a paper in the well-regarded scientific journal Nature.
“If this is true,” Mikkel Winther Pedersen, a geogeneticist at the University of Copenhagen in Denmark who was not directly involved in the study, tells Business Insider, “it would rock the ground that we are standing on at the moment, not just for all archaeologists but for all the other researchers interested in this.”
The proposed timeline revision is based on a set of 130,000-year old mastodon bones (dated using uranium) that show signs of having been processed by humans, according to the paper. At the archaeological site, which was first unearthed in the 1990s, researchers discovered pieces of limb bones and teeth from the mastodon, an enormous extinct creature distantly related to the elephant.
The archaeologists say the way those bones were broken tells an important story.