San Diego Natural History Museum
Humans may have arrived in North America 130,000 years ago, a new study suggests today in Nature.
Why it matters: This means humans may have arrived in North America much earlier than previously thought, surpassing previous evidence of human activity in North America — showing activity 15,000 to maybe 30,000 years ago — by 100,000 years.
The remains: Bones of a mastodon (a relative of elephants) had spiral fractures, indicating they were broken by the hammerstones and anvils surrounding the remains, indicating humans killed the mastodon.
The skeptics: John Hellstrom of the University of Melbourne told The Atlantic the technology used to date the remains makes it so you can't pin down the age of 130,000 years. Archaeologist Donald Grayson cautioned there could be other explanations for the marking on the bones.
What's next: Finding a human skeleton from the same time period and determining how humans got to North America 130,000 years ago, since the sea lane of the Bering Strait, which humans likely used to migrate to North America, was much wider 130,000 years ago.
One big question: Why hasn't anyone else found evidence of human activity this far back? One of the scientists suggested we just haven't been looking that far back.
Editor's note: This article has been updated to better reflect concerns about the limitations of this study.