Let’s begin by tracing the argument: for a good long time, the belief of the scientific/paleontology/anthropology community was that the first people to begin arriving in America were “the Clovis People.” They seemed to appear about 13,500 to 13,000 years ago, and the idea held that they crossed the Beringia Land Bridge from Siberia to Alaska during a period of lowered sea levels, then went south through an ice-free avenue east of the current Rocky Mountains. (I’m sure you remember some of this, at least the land bridge part, from sixth grade science or history.) The ‘Clovis First’ idea was the conventional logic about people appearing in the Americas for many years, but then … Monte Verde, in southern Chile, was excavated — and info there predates the Clovis people by about 1,000 years. Monte Verde directly contradicts the ‘Clovis First’ concept, and is based mostly on the idea of coastal migration (coming down the Western part of America). People were apparently in Monte Verde 1,800 years before the Bering Land Bridge would have been impassable (13,000 years ago or so). So we went from ‘Clovis First’ to ‘Monte Verde’ as explaining the origins of humans in the Americas.
Now a new player is in the field. At Arroyo del Vizcaíno in southern Uruguay, which has been radiocarbon-dated to about 29,000 to 30,000 years old, there’s evidence that humans could have been killing giant sloths. This evidence isn’t conclusive yet — it’s possible that some of the stone tools found, for example, could have been made that way by nature — but it presents an interesting theory, because here we’re talking about twice the amount of time back into the past. In short, it would mean humans might have been in the Americas 30K years ago, which is about 17K years further back than we thought. These theories were published this month, and the team involved has developed a site about it (it’s in Spanish, but you can translate it too). Richard Farina, one of the co-authors, called it “strange and unexpected” because it’s “pretty old for a site with human presence.”
Where we stand now: the ‘Clovis First’ idea is probably out for good. Monte Verde seems to have the title right now, but these discoveries in Uruguay should shake up the ideas we have about the migration of early humans. Also very cool about the Uruguay site: one of the bone structures they found has been classified as a toxodon since; the toxodon has no related animal relatives, apparently.
The Uruguay team is planning more excavations and environmental re-creations to shed more light on their initial findings; this article from Discovery has some more quotes from Farina, including the idea that giant sloths, if a food source for the earliest inhabitants, could have weighed two to four tons and grown to be 15 feet tall. In this article, other scientists speak of the new site being on “collective radar screens” now.
The peopling of the Americas is an incredibly interesting topic for me, mostly because, well, science can work for generations on it and no one’s really ever going to know exactly how it happened. Was there one guy or girl in the group who decided to start walking in a different direction? How did the earliest humans figure out which plants were safe and which weren’t? (Trial and error?) How did the earliest humans figure out sex, and how did they figure out gestation and delivery? Were they literally walking across an ocean, or rather, what we know as an ocean today? When they encountered a beast like a giant sloth, how did they know how to slay it and then eat it? Is this map at all accurate?
I don’t know much about science, but … if there were people living in southern Uruguay 30K years ago, that seems to change the entire game about how migration patterns worked. And maybe Arroyo del Vizcaíno will roll off the lips of generations of future schoolchildren, just like we all remember the Bering Strait — or at least we had to remember it for tests.
Just FYI, because it took me a while to figure out as well, here’s a map of the area near the new discoveries: