Until 20 years ago, the prevailing theory
for how the earliest human settlers arrived in America
came down to one thing: big game
It was thought that humans followed megafauna
such as mammoths and bison across the Bering strait
and through an ice-free corridor down
into North America around 13,500 years ago.
These early humans, the Clovis,
left behind spear points with telltale grooves,
evidence of their big game hunts.
But this theory collapsed
when evidence of human occupation
dating to 14,500 years ago
was found at the Monte Verde site in Chile--
1,000 years before Clovis points
appear in North America.
This gave rise to a new theory--
that humans may have traveled by boat,
starting in Beringia
and sailing down the coast
some 16,000 years ago.
Since the discovery at Monte Verde,
researchers have turned their attention
to the Pacific coast in search of early sites.
Cedros Island is practically brimming
with archaeological evidence
for an early American culture that
had mastered coastal environments.
Stone tools and clam shells found at
several sites on the island were radiocarbon dated
to between 11,000 and 13,000 years ago,
not quite pre-Clovis, but getting there...
In the hunt for evidence of these early settlers,
researchers have been searching not only on land
but also under the sea.
As the ice sheets covering North America
began to melt around 16,500 years ago,
the sea level rose 120 meters,
likely swamping any early settlements
along the Pacific coast.
To uncover these drowned settlements,
researchers tried to deduce the location
of these settlers’ most important resource--
fresh water.
They started mapping the ocean floor
off the coasts of Oregon and California,
in search of evidence of
ancient riverbanks and estuaries.
By taking core samples of the ocean floor
where these riverbanks lie, researchers hope
to understand these lost environments
and perhaps even eventually find
evidence of early human occupation.
As the glaciers melted and sea levels rose,
parts of the coasts of British Columbia and
southwestern Alaska rose as well,
no longer bearing the weight of the
massive sheets of ice.
The consequences of this geological quirk
can be found on Calvert Island, where the
sea level rise was as little as 2 meters,
leaving easily accessible evidence
of coastal settlements.
Here researchers found 29 footprints
preserved in clay buried underneath a
half a meter of soil.
A piece of wood embedded in one of the footprints
allowed them to date the footprints to just
over 13,000 years ago.
More evidence has been found
on nearby coastal islands,
12,700-year-old spear points left
over from a bear hunt and
14,000-year-old stone tools left next to a hearth.
Clues that the first Americans made their way down
the coast by boat continues to present themselves,
but archaeologists aren’t ready to confirm the theory just yet.
A string of well-documented sites along the coasts of
southwestern Alaska and British Columbia
dating back to at least 15,000 years ago
and extending through time down the coast
will be needed to truly prove
the coastal migration theory.
Until then, archaeologists in both
North and South America
will continue the hunt for signs
that the earliest Americans were, indeed,
a seafaring people.
