Beringian Standstill - And More

 For people to drop a theory, they usually have to have a new one to move to. We do not easily sustain the idea “we just don’t know.”  The brain doesn’t like it.  The brain wants a story, preferably a simple one, in order to put the data into a nice folder and move on to other things. It was more than twenty years ago that the theory that the Clovis people were the first to the Americas (about 13,000ya) was shown to be inadequate, but the idea has lingered on with apologies until recently.  There are three reasons I can see.  The Clovis people are the main ancestors of a huge chunk of the Native Americans alive today.  While people all over the landscape before then are interesting, we don’t care so much about those who went extinct without leaving descendants. Secondly, Clovis points are really cool, and we like looking at them. 

But mostly, we hung around the burned-out building of Clovis First because we didn’t have any other place to go.  There were pre-Clovis finds in Pennsylvania, Virginia,  and the whole Western Stemmed tradition in Nevada, Oregon, and Idaho. There were Mexican and South American finds almost ridiculously older  and even some weird genetic find in the Amazon which I mentioned two years ago, but nothing connected them, and there wasn’t a full narrative attached.  The Solutrean Hypothesis came and (I think) went. A general picture of pre-Clovis people inching down the Pacific coastline from vanishing Beringia, moving inland up rivers at first but eventually disappearing, is now emerging.

Key to all of these was the idea of the Beringian Standstill, not because it was the only possible explanation (it is not), but because it is easy to picture and increases the plausibility of long-distance migration.  The arrows on the maps, whichI recently reminded you not to trust showed Siberians following mammoths and other megafauna almost as if the humans were chasing them there, across the Beringian Land-bridge just before it closed and then spreading rapidly throughout the Americas.  Whew. Just in time. That those Siberians might have lingered long or traveled slowly along the land-bridge was known to be possible, but somehow neglected.  We did name it a land-bridge, after all, focusing on the fact that they went from there to here. Yet the land-bridge was a savanna – colder than the prairies or African, Australian, or Asian savannaswe think of, but still, an open grassland with some trees, some of it 500 miles from any ocean and great habitat for big animals we could eat. The Siberians stayed, went “back,” went “forward,” or more accurately lived there for thousands of years.  Even after making it to North America, some went back for good, and we can find their genetic traces on the Chukchi Peninsula.

 Glaciers take a heckuva lot of water out of the oceans, and drop see levels by up to 150 meters, exposing a lot of land.  (This also happened in Sundaland in SE Asia, Indonesia, New Guinea, which is important in human genetics and settlement in a different era.  Savannas are big now in discussing human origins and movements.  As they should be.) When humans live there and thrive, they move in all directions as the land disappears, and all physical traces of their existence there go under the waves.  Why don’t we see evidence of all these early peoples in the lovely shellfish and salmon-rich coastal areas inhabited by Native Americans even to this day?  Because those weren’t coastal areas then. The old coastal areas are now continental shelf off Cascadia.

Here is the new picture.  It easily incorporates the newer finds in addition to Clovis.  Tribes moved from that Beringian savanna in both directions, probably many times.  Most of them didn’t survive here, not even enough to interbreed with a new wave of long-since Siberians coming in. 

 

Tangential note, but very cool: Those North Eurasians with a blue line mixing in with the orange one from the south?  Those are Ancient North Eurasians (ANE) who ranged across the top of Asia all the way back to the Atlantic. It was surprising to find some deep ancestry shared between Native Americans and some Europeans.  This is how.  They both have ANE in them, especially the Uralic populations like Finns and Saami.

Great huh? Except now there are finds from earlier, even far earlier migrations, reported last month from the highlands of Mexico.  Highlands. Mexico.  Not very close to the Aleutians. They have said numbers over 30,000 years.

That would double the time-depth of migration to the new world, as these are evidence for humans in the New World even before there was a Beringian Land-Bridge Savanna. Not to worry though.  They don’t seem to have left any descendants, so we won’t care so much.  Except maybe that squirrelly Austronesian genetic material far up the Amazon. And Lord knows what else.