Radio-carbon dating on an ancient bone fragment has revealed that we’ve been hunting in North America about a thousand years prior to what we used to think.

From this story in the New York Times:
For many years, it was thought that the Clovis people were the first humans to populate North America, about 13,000 years ago. But recently, evidence has suggested that other settlers arrived earlier, and a new study lends support to that hypothesis. The study, in the journal Science, finds that a mastodon rib with a bone point lodged in it dates back 13,800 years._

_”It’s the first hunting weapon found pre-Clovis,” said the lead author, Michael R. Waters, an archaeologist at Texas A&M University. “These people were hunting mastodons.” The fossils had been discovered in the late 1970s at a dig known as the Manis site, near Sequim, Wash., by Carl Gustafson, an archaeologist at Washington State University. At the time, Dr. Gustafson proposed that the skeleton was about 14,000 years old and that hunters had killed the mastodon with a bone point.

His theory was questioned by other scientists. But carbon dating technology has improved since then, and Dr. Waters and his colleagues — including Dr. Gustafson — were able to use mass spectrometry to date the rib, the bone point and tusks that were found at the site. They also used CT scanning to closely study the embedded bone point to confirm that it was a hunting tool. They found that the point was more than 10 inches long and that it had been sharpened. “It couldn’t have been anything else,” Dr. Waters said._