WASHINGTON (By Will Dunham, Reuters) February 25, 2007 — The Clovis people, known for their distinctive spear points, likely were not the first humans in the Americas, according to research placing their presence as more recent than previously believed.

Using advanced radiocarbon dating techniques, researchers writing in Friday's issue of the journal Science said the Clovis people, hunters of large Ice Age animals such as mammoths and mastodons, dated from about 13,100 to 12,900 years ago.

That would make the Clovis culture, known from artifacts discovered at various sites including the town of Clovis, N.M., both younger and shorter-lived than previously thought. Previous estimates had dated the culture to about 13,600 years ago.

These people long had been seen as the first humans in the New World, but the new dates suggest their culture thrived at about the same time or after others also in the Americas.

Michael Waters, director of Texas A&M University’s Center for the Study of the First Americans, called the research the final nail in the coffin of the so-called “Clovis first” theory of human origins in the New World.

Waters said he thinks the first people probably arrived in the Americas between 15,000 and 25,000 years ago.

“We’ve got to stop thinking about the peopling of the Americas as a singular event,” Waters said in an interview.

“And we have to start now thinking about the peopling of the Americas as a process, with people coming over here, probably arriving at different times, maybe taking different routes and coming from different places in northeast Asia.”

Waters and co-author Thomas Stafford, a radiocarbon dating expert, tested samples from various Clovis archeological sites to try to get a more accurate accounting of their age. Technological advances enabled them to more precisely pinpoint dates for some Clovis sites excavated in North America.

The theory has been that the Clovis people first migrated out of northeast Asia across the Bering land bridge from Siberia into Alaska and traveled through a ice-free corridor into North America, populating that continent while their descendants journeyed into South America.

Asked who were the first people in the Americas, if not the Clovis, Waters answered, “That’s a good question.”

“I think that’s what we’ve got to work toward — a new model for the peopling of the Americas, and I think we need to create a coherent model that’s based on genetic data, geological evidence as well as archaeological data.”