Half-chewed seaweed in southern Chile and fossilized feces unearthed in an Oregon cave are helping scientists build a case for the arrival of the first migrants in the Americas thousands of years earlier than previously believed.
These archaeological finds - unveiled within the past month - contribute to an evolving story in which the first migrants arrived in the Americas from Siberia between 15,000 and 16,000 years ago. They then appear to have trekked south along the west coasts of North and South America.
Some researchers say the new finds also allow them to begin speculating about social organization, health practices, and how well the newcomers exploited their diverse surroundings.
Several researchers working on the question remain skeptical of the revised picture. Scientific debates over the first appearance of humans in the Western Hemisphere are far from over, acknowledges Ted Goebel, associate director of the Center for the Study of the First Americans at Texas A&M University in College Station, Texas.
But in a recent article surveying the field, he and two colleagues note that the longstanding view that the so-called Clovis culture represents the earliest human occupation of the Americas is getting harder to defend. It would mean rejecting the growing number of sites that appear much earlier, "and this appears to be no longer possible," they write.
For example, scientists working a settlement site in southern Chile have unearthed what they interpret as stone-cutting tools, one of which had small particles of seaweed on the blade, according to research published Thursday in the journal Science.
The site, dubbed Monte Verde II and increasingly acknowledged as the oldest settlement in the Western Hemisphere, lies 55 miles east of the coastline of that time.
The team, led by Vanderbilt University archaeologist Tom Dillehay, found several species of seaweed, including five species they hadn't seen there before. In addition, they found algae that normally grows on trees and rocks along the coast. The seaweed specimens were found in soil from the floors of a what scientists think was a residential and a medicine hut.
The seaweed samples are between 13,980 and 14,220 years old. The oldest Clovis sites, by contrast, are some 13,000 years old.
The finds have some intriguing implications, Dr. Dillehay says. The variety of plant, seaweed, and animal remains found, along with the site's riverside location, suggest that the Monte Verdeans had lived there long enough to develop a detailed understanding of the range of food and medicinal resources available to them from the coast well into the mountains. …