Specifically, shit about shit like climate change.
The Cahokia were a tribe that flourished near Illinois around 1200 AD, with a population of 20,000 people at its peak. But their ancient city was mysteriously abandoned by 1400 AD.
Now, scientists believe human faecal molecules washed into a nearby lake show evidence of a severe drought.
Information from from the waste matter was dated by how deep it was found in the lakes’ sedimentation.
The ancient city stood near St. Louis, Missouri, and was the largest prehistoric settlement in Americas north of Mexico.
Studying lake sediments from a lake next to Cahokia, researchers at California State University concluded there was a shift towards lower summer rainfalls levels in A.D 1150.
Among other elements, they looked at faecal stanols, molecules present in grains, peanuts and vegetable oils, which are eliminated in feces.
The more people who lived and defecated there, the more stanols evident in lake sediments, so stanols can be used as a tag population size and movement.
AJ White, lead author on the study from Wisconsin-Madison, said: ‘The way of building population reconstructions usually involves archaeological data, which is separate from the data studied by climate scientists’.
‘Because the sediments of a lake accumulate in layers, they allow scientists to capture snapshots of time throughout the history of a region through sediment cores.
‘Deeper layers form earlier than layers found higher up, and all of the material within a layer is roughly the same age.’
The data from the study showed that summer precipitation likely decreased around the onset of Cahokia’s decline.
This could have affected the ability of people to grow their staple crop maize.
The latest changes are thought to have concurred with a major flooding event around the same period from the Mississippi River.
Consecutive years of summer droughts followed by a major flooding would have put severe pressure on the settlement’s agricultural system and could explain why the city was suddenly abandoned.