Nestled on the banks of the Mississippi River, the forgotten city
of Cahokia was once a bustling metropolis, the largest and most
cosmopolitan hub north of Mexico, home to the Mississippian indigenous
culture.
Today, no one knows what happened to it. Tens of thousands of its
inhabitants are merely said to have 'disappeared', leaving behind
their giant earthen mounds, spread across 13
square kilometres (5 square miles).
By the mid 1300s, long before white settlers arrived on the continent,
archeologists say it was virtually abandoned.
A fresh analysis of ancient human faeces has now weaved a wholly
different story.
The Cahokia area, it reveals, was only forsaken briefly. By the
time Columbus sailed the ocean blue, the metropolis - which was
located in modern-day Illinois near what is now St. Louis - was
already being repopulated, and by 1650, the number of its residents
had surged to a whole new high.
"The story of Cahokia was a lot more complex than, 'Goodbye, Native
Americans. Hello, Europeans,' and our study uses innovative and
unusual evidence to show that," says
anthropologist AJ White from the University of California Berkeley.
The widespread abandonment of Cahokia between 1450 and 1550 CE
is a time known as the 'vacant quarter'. Over the years, archaeological
investigations have indicated several contributing factors to this
slump, including conflict, population movement, flooding, drought,
climate change, and the over-exploitation of resources.
But while many have remained focused on the Cahokia collapse, few
have researched what happened after.
Widespread acceptance of the vacant quarter hypothesis has perpetuated
the "myth
of the vanishing Indian", the authors argue, even though historical
accounts suggest
Mississippian culture never collapsed completely.
"One would think the Cahokia region was a ghost town at the time
of European contact, based on the archeological record," says
White.
"But we were able to piece together a Native American presence
in the area that endured for centuries."
As well as using historical, climatic and ecological data, the
team decided to supplement their work with faecal evidence. After
all, wherever humans live, we defecate.
Certain molecular signatures in human poop, called stanols, can
be washed into lakes and other basins by the rain, which means the
more stanols you find in ancient sediments, the more people who
likely lived nearby.
Not far from Cahokia's famous mounds in the state of Illinois,
archaeologists dug up two sediment cores from opposite sides of
Horseshoe Lake.
The results suggest that after hitting a low point, the population
in this area began to resurge again in 1500 CE, indicating that
any lack of growth was short-lived.
Only in 1700, well after European arrival, did fecal stanol ratios
begin to show a decline.
"It is important to note that the depopulation of Cahokia in the
twelfth to fourteenth centuries was not the end of an indigenous
presence in the Horseshoe Lake watershed, despite a lack of archaeological
evidence and research emphasis on Mississippian occupations," the
authors write.
"By acknowledging a repopulation following the Mississippian decline,
we move closer to a narrative of native persistence over disappearance."
The timing of it all is pretty remarkable, too. During the population
increase, other native populations in the United States, Canada
and the Caribbean were in serious decline from violence and foreign
diseases spread by European colonists.
Far from the coast, the inhabitants of Cahokia were likely shielded
for a time, although not forever. Today, many claim the Illinois
tribe is no more, but White and his colleagues argue "regional depopulation
and relocation do not equate to cultural extinction".
In a previous study using ancient human poop samples, published
last year, White found evidence of droughts and floods that might
have contributed to Cahokia's fluctuating population in the 1300s.
"Cultures can be very resilient in face of climate change but resilience
doesn't necessarily mean there is no change. There can be cultural
reorganization or decisions to relocate or migrate," explained anthropologist
Sissel Schroeder at the time.
Disappearing completely is another matter. Through warfare, disease,
removal, environmental change, and political upheaval, Cahokia might
have persisted for much longer than we thought.
The study was published in American
Antiquity.
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