First Americans
New finds, theories, and genetic
discoveries are revolutionizing our understanding of the first Americans.
By Glenn Hodges in National
Geographic magazine
The first face of the first
Americans belongs to an unlucky teenage girl who fell to her death in a
Yucatán cave some 12,000 to 13,000 years
ago. Her bad luck is science’s good fortune. The story of her discovery begins
in 2007, when a team of Mexican divers led by Alberto Nava made a startling
find: an immense submerged cavern they named Hoyo Negro, the “black hole.” At
the bottom of the abyss their lights revealed a bed of prehistoric bones,
including at least one nearly complete human skeleton.
Nava reported the discovery to
Mexico’s National Institute of Anthropology and History, which brought together
an international team of archaeologists and other researchers to investigate
the cave and its contents. The skeleton—affectionately dubbed Naia, after the
water nymphs of Greek mythology—turned out to be one of the oldest ever found in
the Americas, and the earliest one intact enough to provide a foundation for a
facial reconstruction. Geneticists were even able to extract a sample of DNA.
Together these remnants may help
explain an enduring mystery about the peopling of the Americas: If Native
Americans are descendants of Asian trailblazers who migrated into the Americas
toward the end of the last ice age, why don’t they look like their ancient
ancestors?
By all appearances, the earliest
Americans were a rough bunch. If you look at the skeletal remains of
Paleo-Americans, more than half the men have injuries caused by violence, and
four out of ten have skull fractures. The wounds don’t appear to have been the
result of hunting mishaps, and they don’t bear telltale signs of warfare, like blows
suffered while fleeing an attacker. Instead it appears that these men fought
among themselves—often and violently.
The women don’t have these kinds of
injuries, but they’re much smaller than the men, with signs of malnourishment
and domestic abuse.
To archaeologist Jim Chatters,
co-leader of the Hoyo Negro research team, these are all indications that the
earliest Americans were what he calls “Northern Hemisphere wild-type”
populations: bold and aggressive, with hypermasculine males and diminutive, subordinate
females. And this, he thinks, is why the earliest Americans’ facial features
look so different from those of later Native Americans. These were risk-taking
pioneers, and the toughest men were taking the spoils and winning fights over
women. As a result, their robust traits and features were being selected over
the softer and more domestic ones evident in later, more settled populations.
Chatters’s wild-type hypothesis is
speculative, but his team’s findings at Hoyo Negro are not. Naia has the facial
features typical of the earliest Americans as well as the genetic signatures
common to modern Native Americans. This signals that the two groups don’t look
different because the earliest populations were replaced by later groups
migrating from Asia, as some anthropologists have asserted. Instead they look
different because the first Americans changed after they got here.
Chatters’s research is just one
interesting development in a field of study that has been exploding in fresh
directions over the past two decades. New archaeological finds, novel
hypotheses, and a trove of genetic data have shed fresh light on who the first
Americans were and on how they might have come to the Western Hemisphere. But
for all the forward motion, what’s clearest is that the story of the first
Americans is still very much a mystery.
For most of the 20th century it was assumed that the mystery had been more or less
solved. In 1908 a cowboy in Folsom, New Mexico, found the remains of an extinct
subspecies of giant bison that had roamed the area more than 10,000 years ago.
Later, museum researchers discovered spearpoints among the bones—clear evidence
that people had been present in North America much earlier than previously
believed. Not long after, spearpoints dating to 13,000 years ago were found
near Clovis, New Mexico, and what became known as Clovis points were
subsequently found at dozens of sites across North America where ancient
hunters had killed game.
Given that Asia and North America
were connected by a broad landmass called Beringia during the last ice age and
that the first Americans appeared to be mobile big-game hunters, it was easy to
conclude that they’d followed mammoths and other prey out of Asia, across
Beringia, and then south through an open corridor between two massive Canadian
ice sheets. And given that there was no convincing evidence for human
occupation predating the Clovis hunters, a new orthodoxy developed: They had
been the first Americans. Case closed.
That all changed in 1997 when a team
of high-profile archaeologists visited a site in southern Chile called Monte
Verde. There Tom Dillehay of Vanderbilt University claimed to have discovered
evidence of human occupation dating to more than 14,000 years ago—a thousand
years before the Clovis hunters appeared in North America. Like all pre-Clovis
claims, this one was controversial, and Dillehay was even accused of planting
artifacts and fabricating data. But after reviewing the evidence, the expert
team concluded it was solid, and the story of the peopling of the Americas was
thrown wide open.
How did people get all the way to
Chile before the ice sheets in Canada retreated enough to allow an overland
passage? Did they come during an earlier period of the Ice Age, when this
inland corridor was ice free? Or did they come down the Pacific coast by boat,
the same way humans got to Australia some 50,000 years ago? Suddenly the field
was awash in new questions and invigorated by a fresh quest for answers.
In the 18 years since the Monte
Verde bombshell dropped, none of these questions have been resolved. But the
original question—Was Clovis first?—has been answered repeatedly, with several
sites in North America making their own claims to pre-Clovis occupation. Some
of these places have been known and studied for years and have gained fresh
credibility in the wake of Monte Verde’s acceptance, but there have been new
finds as well. One location in particular, the Debra L. Friedkin site in
central Texas, might even be the earliest place of demonstrable human habitation
in the Western Hemisphere.
In 2011 archaeologist Michael Waters of Texas A&M University announced that
he and his team had unearthed evidence of extensive human occupation dating to
as early as 15,500 years ago—some 2,500 years before the first Clovis hunters
arrived. The Friedkin site lies in a small valley in the hill country about an
hour north of Austin, where a tiny perennial stream now called Buttermilk
Creek, along with some shade trees and a seam of chert, a type of rock useful
for toolmaking, made the area an attractive place for people to live for
thousands of years.
“There was something unique about
this valley,” Waters says. It was long thought that the earliest Americans were
primarily big-game hunters, following mammoths and mastodons across the
continent, but this valley was an ideal place for hunter-gatherers. People here
would have eaten nuts and roots, crawdads and turtles, and they would have
hunted animals such as deer and turkeys and squirrels. In other words, people
probably weren’t here on their way to somewhere else; they were here to live.
But if Waters is right that people
were settled here, in the middle of the continent, as early as 15,500 years
ago, when did the first arrivals cross into the New World from Asia? That’s
unclear, but it appears that people may have been settled in other parts of the
continent at the same time. Waters says the pre-Clovis artifacts he’s found at
Buttermilk Creek—more than 16,000 of them, including stone blades, spearpoints,
and chips—resemble artifacts found at sites in Virginia, Pennsylvania, and
Wisconsin.
“There’s a pattern here,” he says.
“I think the data clearly show that people were in North America 16,000 years
ago. Time will tell if that represents the initial occupation of the Americas
or if there was something earlier.”
Either way, the newest
archaeological evidence comports with an increasingly important line of
evidence in our understanding of the peopling of the Americas. In recent years
geneticists have compared the DNA of modern Native Americans with that of other
populations around the world and concluded that the ancestors of Native
Americans were Asians who separated from other Asian populations and remained
isolated for about 10,000 years, based on mutation rates in human DNA. During
that time they developed unique genetic signatures that only Native Americans
currently possess.
These genetic markers have been
found not only in the DNA recovered from Naia’s skeleton but also in the
remains of a child buried some 12,600 years ago in western Montana, on a piece
of land now called the Anzick site. Last year Danish geneticist Eske Willerslev
reported that an analysis of the child’s remains had yielded, for the first
time, a full Paleo-American genome.
“Now we’ve got two specimens, Anzick
and Hoyo Negro, both from a common ancestor who came from Asia,” Waters says.
“And like Hoyo Negro, the Anzick genome unquestionably shows that
Paleo-Americans are genetically related to native peoples.”
Though some critics point out that
two individuals are too small a sample to draw definitive conclusions, there’s
strong consensus on the Asian ancestry of the first Americans.
So how and when did the earliest
inhabitants of the New World get here? That remains an open question, but given
that people made it all the way to southern Chile more than 14,000 years ago,
it would be surprising if they hadn’t journeyed by boat.
The Channel Islands off the southern California coast are rugged and wild, home
to a national park, a national marine sanctuary, and a training post for U.S.
Navy SEALs. The archipelago also harbors thousands of archaeological sites,
most of them still undisturbed.
In 1959, while exploring Santa Rosa
Island, museum curator Phil Orr discovered a few bones of a human he named
Arlington Springs man. At the time, the bones were judged to be 10,000 years
old, but 40 years later researchers using improved dating techniques fixed the
age at 13,000 years—among the oldest human remains ever discovered in the
Americas.
Thirteen thousand years ago the northern
Channel Islands—then fused into a single island—were separated from the
mainland by five miles of open water. Clearly Arlington Springs man and his
fellow islanders had boats capable of offshore travel.
Jon Erlandson of the University of
Oregon has been excavating sites on these islands for three decades. He hasn’t
found anything as old as Arlington Springs man, but he has found strong
evidence that people who lived here slightly later, some 12,000 years ago, had
a well-developed maritime culture, with points and blades that resemble older
tools found on the Japanese islands and elsewhere on the Asian Pacific coast.
Erlandson says that the Channel
Island inhabitants might have descended from people who traveled what he calls
a kelp highway—a relatively continuous kelp-bed ecosystem flush with fish and
marine mammals—from Asia to the Americas, perhaps with a long stopover in
Beringia. “We know there were maritime peoples using boats in Japan 25,000 to
30,000 years ago. So I think you can make a logical argument that they may have
continued northward, following the Pacific Rim to the Americas.”
Beaches along the Pacific coast
still teem with elephant seals and sea lions, and it’s easy to imagine hunters
in small boats moving swiftly down the coastline, feasting on the abundant
meat. But imagination is no substitute for hard evidence, and as yet there is
none. Sea levels are 300 to 400 feet higher than at the end of the last glacial
maximum, which means that ancient coastal sites could lie under hundreds of
feet of water and miles from the current shoreline.
Perhaps ironically, the best
evidence for a coastal migration might be found inland, as people traveling
along the coast would likely have explored rivers and inlets along the way.
There is already suggestive evidence of this in central Oregon, where
projectiles resembling points found in Japan and on the Korean Peninsula and
Russia’s Sakhalin Island have been discovered in a series of caves, along with
what is surely the most indelicate evidence of pre-Clovis occupation in North
America: fossilized human feces.
In 2008 Dennis Jenkins of the
University of Oregon reported that he’d found human coprolites, the precise
term for ancient excrement, dating to 14,000 to 15,000 years old in a series of
shallow caves overlooking an ancient lake bed near the town of Paisley. DNA
tests have identified the Paisley Caves coprolites as human, and Jenkins
speculates that the people who left them might have made their way inland from
the Pacific by way of the Columbia or Klamath Rivers.
What’s more, Jenkins points to a
clue in the coprolites: seeds of desert parsley, a tiny plant with an edible
root hidden a foot underground. “You have to know that root is down there, and
you have to have a digging stick to get it,” Jenkins says. “That implies to me
that these people didn’t just arrive here.” In other words, whoever lived here
wasn’t just passing through; they knew this land and its resources intimately.
That seems to be an emerging theme.
It appears to be the story not just at Paisley Caves but at Monte Verde and the
Friedkin site in Texas as well. In each of these cases people seemed to have
been settled in, comfortable with their environment and adept at exploiting it.
And this suggests that long before the Clovis culture began spreading across
North America, the Americas hosted diverse communities of people—people who may
have arrived in any number of migrations by any number of routes. Some may have
come by sea, others by land. Some may have come in such small numbers that
traces of their existence will never be found.
“There’s a whole lot of stuff that
we don’t know and may never know,” says David Meltzer, an archaeologist at
Southern Methodist University. “But we’re finding new ways to find things and
new ways to find things out.”
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