While geneticists open up intellectual frontiers, archaeologists are searching for ways to test the migration theories in the field. Direct evidence for coastal migration will be hard to come by, because a rise in the sea level since the end of the last ice age has flooded the ancient coastlines. But researchers are turning up indirect evidence in many locations. Last year, for example, Erlandson demonstrated that humans lived on California's Channel Islands as far back as 12,200 years ago9
, which shows that they must have mastered the use of boats before that time.
And at the Monte Verde site in Chile, researchers have found evidence that the ancient occupants were fans of seafood10
. “Monte Verde has ten different species of seaweed at the site,” Dillehay says. “Somebody was intimately familiar with seaweeds and the microhabitats where they could be found.” That lends support to the idea that the earliest Americans were seafarers, he says.
Dillehay's recent findings, which came 30 years after the first excavations at Monte Verde, show that previously studied sites can become potential gold mines, says Waters. Because so many sites were either dismissed or forgotten during the 'Clovis-first' era
, Waters says that “the field can really be pushed forward by going back and taking a look at sites that were put up on a shelf”. He is already planning to reopen sites in Tennessee and Florida, where evidence of pre-Clovis mammoth hunting was uncovered in the 1980s and 1990s.
Geneticists and archaeologists agree that the death of the Clovis theory has injected the field with excitement and suspense. “There's a sense that there was something before Clovis,” says Jenkins, whose coprolite study shook the field four years ago. “But what it was and how it led to the patterns that we see in North and South America — that's a whole new ball game.”