Especially the reason for the city’s ceasing to exist is a mystery to many scientists and there are various more or less well-founded explanations. Authors are very apt to create a bit of an ideal-world-image of a highly developed society when talking about Cahokia. They like stressing that things were running perfectly fine in Cahokia and they are reluctant to continue writing when it comes to the point where they have to explain why Cahokia ceased to exist.
Fact is that – after prevailing for more than 500 years, “Cahokia declined in 1200-1400 A.D. and was utterly abandoned by 1500”. ( 20.07.2001) Actually, this is a part of the Cahokian story that provokes the wildest assumptions. Archaeologists have come up with several theories about the city’s fate and whilst some sites pretend to know the facts, others content themselves with just listing the possible explanations.
More or less, I will try to do the same by listing them while trying at the same time to figure out their weaknesses and strengths. The following will present some of them – either of them relying more or less on speculation and archeological funds.
exhaustion of natural resources & climate change
Depletion of resources probably contributed to the city's decline. This could have been due to a climate change or the exhaustion by the Cahokians. A large populations like Cahokia’s requires additional resources. Excessive tree cutting, for instance for fire and constructions like the stockade, as well as a landscape change due to maize fields around the city, certainly destroyed wildlife habitat. This went along with an ever-increasing demand on natural resource and the fact that people may have hunted the local game to extinction.
Possibly, it was this increasing demand for natural resources that led to a climate change.
“One theory says their increasing reliance on lumber for fuel, houses and temples [as well as maize agriculture] culture may have caused [the city’s] collapse. Removing too much timber from the area would have left nothing to anchor the soil, so that heavy rainfall would have washed it away, wiping out the crops.” (http://www.allsands.com/History/Places/indiansmoundbui_ib_gn.htm 19.07.2001)
However, life in the valley of one of the world's mightiest rivers as such might have posed a considerble risk to the Cahokians. Yearly flooding as well as large scale flooding destroying the fields, were likely to have happened.
problems not unlike those that plague modern cities, especially the havoc created by too much growth” and he continues: “Five or six centuries after its birth, America's first city, unable to cope with change, was a ghost town” (Lewis Lord in: 19.07.2001). It is suggested that due to its rapid growth and “the heavy reliance on starchy foods like corn and the high population densities of larger towns may have led to malnutrition and encouraged the spread of diseases“.(http://archive.ncsa.uiuc.edu/Cyberia/RiverWeb/History/Cahokia/miss/health.html)
Several articles argue that infectious disease and poor diet spread. Furthermore, the lack of any sanitary systems for disposing of garbage and human waste fostered the spreading of diseases like dysentery and tuberculosis (see 20.07.2001). These assumptions seem to be backed up by observation of skeletons (see http://archive.ncsa.uiuc.edu/Cyberia/RiverWeb/Projects/Ambot/prehistory/mississippian/top.html 09.10.2001).
One common assumption is that warfare or violence of any kind were the main reasons for Cahokia to cease to exist. The National Park Service, for instance, on the one hand thinks that especially the surplusses of every sort, which had made life for the Cahokians so easy, were reason for greed and - consequently – fighting for land and property. However, the same article argues that a shortcut of ressources life supplies of any kind caused by Cahoki’s massive growth was a reason for Cahokia’s decline.
It seems that – for a city of Cahokia’s
importance - war became a necessary tool for enforcing
political control. However, we do not know, whether they fought on reasons of competing for land, “induced,
perhaps, by their ever-increasing numbers” (http://www.cr.nps.gov/aad/feature/riverlif.htm
or whether “Cahokia,
because of its sheer size and magnitude relative to neighboring Mississippian
groups, might have been perceived as a credible military threat to far off
groups” (Robert J. Jeske in:
Warfare is, at least, a possible explanation for the creation of the stockade and archeological finds of the time, showing an increase in martial symbolism.
is biological and archaeological evidence for warfare. In addition to skeletons
bearing evidence of violent death (Milner et al. 1991), some Mississippian
sites are stockaded (Goldstein and Richards 1991), and there are symbolic
representations of pottery and shell engravings, suggesting that a warrior
class or at least some form of warrior veneration existed (Phillips and Brown
1978). (Robert J. Jeske in: http://csf.colorado.edu/jwsr/archive/vol2/v2_na.htm)
Some scientists even consider these signs of violence visible on some human remains rather as underscoring this development rather than a proof for human sacrifice. ( I admit, it constitutes a nicer explanation than thinking of a people you use as flaghead - because you regard it as highly civilized - as perfomaning rituals with human sacrifice.)
THE DECLINE OF POLITICAL AND ECONOMIC POWER
On various websites we can find the suggestion that the simple reason for Cahokia’s decline was the breaking apart of its former tight social and topographical network, which could have been due to a whole range of factors. “Some believe that the population grew too large and people began to drift away, others believe that the rulers and priests lost their ability to control the masses.” ( 20.7.2001)
the reasons, one possible explanation for Cahokia’s extinction is the
segmentation of its population. “[…] local residences were structured around their own mound and
plaza complexes. […] In sum, it appears that local communities were oriented to
local elites rather than to a centralized authority (Mehrer and Collins
1995:47).” (Robert J. Jeske in:
http://csf.colorado.edu/jwsr/archive/vol2/v2_na.htm) The “society ‘devolved’ and gradually returned to small-village life” ( 20.07.2001), which left Cahokia as a ghost town.
Some sites such as http://www.interlog.com/~gilgames/cahokia.htm or http://www.jayepurplewolf.com/PHOENIX/CAHOKIA/cahokia.html even go that far to blame the Europeans for the extinction of the Cahokians, whether through warfare or diseases introduced by them. This seems odd, since the Cahokians seem to have disappeared about 90 years before the Europeans arrived on the American continent. But of course it must have been the Europeans who destroyed America’s one only advanced civilization. There has to be someone to be blamed for having destroyed this culture. Thankfully, there are some other sites which refrain from blaming the Europeans for every evil happening to the American continent.
One a whole, many of the sites are very eager to draw conclusions on Cahokia’s fate, just to create a “round” story, however disregarding what scientists actually assume. We may suggest that a network of different causes and incidents together somehow caused Cahokia’s decline. However, since they did not leave any written records, we may never know the truth.