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Archive for December, 2010

Sleeping Ute Mountain and Surrounding Landscape from Four Corners

If you stand at the Four Corners monument and look in the direction of Colorado you will see Sleeping Ute Mountain dominating the view.  From this direction you are looking at the southwest side of the mountain, and in front of it you see the southern piedmont.  On the right side of the piedmont, though not visible from this distance, is Cowboy Wash.  It’s one of several ephemeral streams running from the mountain itself across the piedmont to the San Juan River.

One thing that might strike you about the view from this perspective is that it looks like an awfully dry, desolate, uninhabitable wasteland.  And you would be correct to think that.  The southern piedmont of Sleeping Ute Mountain is an extremely arid and inhospitable environment even by the standards of the Southwest, which is saying something.  It’s only a few miles from Mesa Verde to the east and the Great Sage Plain to the north, both areas that get relatively abundant rainfall and supported large and prosperous prehistoric communities, but it is worlds away from them environmentally.  While those areas get sufficient rainfall to support dry farming, and the Great Sage Plain is commercially farmed even today, the southern piedmont does not, and any type of agriculture there would have to rely on some sort of irrigation.  Today the Ute Mountain Ute tribe has a large irrigation project in the area, using water brought in from McPhee Reservoir, 45 miles to the north, via the Towaoc Canal.  The construction of the reservoir and the canal was part of the Dolores Project, which involved substantial archaeological excavation of the inundated area that significantly improved archaeological understanding of the prehistory of the region.  This work took place from 1978 to 1985 and was known as the Dolores Archaeological Project, the largest salvage archaeology project in US history.

McPhee Reservoir, Dolores, Colorado

The creation of the irrigated fields on the piedmont resulted in further salvage excavations in the 1990s.  Among the sites excavated was 5MT10010, which contained considerable evidence of a gruesome incident of probable cannibalism around AD 1150.  It is not the only site in the area to show evidence of cannibalism during this period; in fact, three other sites in the same community, excavated slightly earlier in connection with the construction of the canal, also showed evidence of having been destroyed in an incident involving extensive processing of human remains in a way suggesting cannibalism, and there are several other sites in the area showing similar assemblages, most from the same period but at least one from a later period.  It is at 5MT10010 that the most solid evidence for actual cannibalism, as opposed to processing of bones in a way that may or may not indicate actual consumption of human flesh, in the form of a coprolite that tested positive for the presence of human muscle tissue.

There are many questions that arise from these findings, but one of the most puzzling is also one of the simplest: what were people doing living at Cowboy Wash in the first place, and how did they manage it?  After all, they weren’t building giant dams and canals of the sort involved in the Dolores Project.  In many parts of the Southwest, especially upland areas like Mesa Verde, dry farming using only rainfall was standard during this period, and water control techniques were generally used only for domestic water if a nearby spring or other reliable source was not available.  There are a few springs on the southern piedmont that probably would have supplied sufficient domestic water for the small number of people living there, but the rainfall would definitely not have been sufficient to farm with.  The only source of water at all sufficient for agriculture would have been the occasional floods, from spring snowmelt and summer thunderstorms, that would flow through Cowboy Wash itself and the other drainages on the piedmont.  None of these flows permanently today, and there is no evidence that they ever did.  As at Chaco Canyon, then, which is similarly dry, farming would have to have been based on some sort of technique for capturing the floodwater.

Flowing Chaco Wash and Cliffs below Peñasco Blanco

There are a variety of ways this might be done, including diverting the rainwater from cliffs, as was done at Chaco, planting along the sides of the drainage where the floods would regularly overflow the banks, and what is known as “ak-chin” farming, as practiced by the O’odham of southern Arizona, which involves planting right in the path of the runoff at places where the velocity of the water is relatively low, as at the mouths of tributaries to main arroyos.  There are no sheer cliffs on the southern piedmont like the ones at Chaco, so probably a mix of overbank and ak-chin farming would have been practiced at Cowboy Wash.

A paper by Gary Huckleberry and Brian Billman addresses the nature of farming at Cowboy Wash, and also addresses a related issue, which is whether periodic entrenchment of arroyos due to drought played a role in the patterns of abandonment and migration that characterize Southwestern prehistory.  It is pretty clear by now that the paleoclimatological record shows periods of drought corresponding to periods of abandonment of certain parts of the Southwest, and one proposed mechanism for how this would have worked is that drought would have led to increased erosion and/or hydrological changes in the water table that led to the entrenchment of arroyos, which would have been disastrous for populations dependent on certain types of floodwater farming (especially overbank), as the broad floodplains of the local drainages would have been replaced by deep channels that took the water away quickly instead of letting it overflow to water the crops.  Ak-chin farmers would not necessarily have been affected to the same degree, but if the side drainages they used became entrenched as well they would not have been able to use their techniques either.  Thus, drought would lead to arroyo-cutting, which would lead people to leave formerly productive areas for others that were less affected.  This theory has been proposed as an explanation for certain events at Chaco, with the idea being that some of the social changes late in the Chacoan occupation were due to degradation of the Chaco Wash and the need to change agricultural strategies.  The phenomenon of arroyo-cutting in general is richly illustrated in historic times at Chaco.  The early reports of the Chaco Wash from the nineteenth century indicate that it was a shallow, meandering drainage, much like the current condition of the Escavada Wash to the north and the “Chaco River” that is formed by the confluence of the two at the western end of the canyon and flows north to the San Juan.  By the early twentieth century, and accelerating since then, however, the Chaco Wash through the canyon has cut down significantly and there is a very deep arroyo channel apparent today.

Entrenched Arroyo at Chaco

The drought-downcutting-abandonment theory makes sense as far as it goes, but as Huckleberry and Billman point out there are some problems.  For one thing, the extent to which arroyo-cutting is actually linked to drought, rather than other factors including the specific geology of the area, is hotly debated and there is no consensus.  The idea that while drought may be one factor causing arroyo-cutting there are other factors involved as well is supported by the fact that in different drainages in the Southwest that have been studied in depth the periods of arroyo-cutting do not necessarily correspond to region-wide droughts or other climatic changes.  In some areas they do, but in other areas they don’t.  At Cowboy Wash specifically, the available evidence indicates that the wash began to entrench sometime before AD 950, and that it began to refill with sediment sometime between AD 1265 and 1400.  If abandonment does in fact correspond to arroyo-cutting, then presumably the Cowboy Wash area should have been abandoned between 950 and 1265, and possibly occupied before and after this.  If downcutting results from drought, there should also be evidence of drought during the 950 to 1265 period.

The basic upshot of the Huckleberry and Billman paper is that neither of these expectations is met.  The evidence for drought conditions at Cowboy Wash generally matches that for the rest of the region, with the major droughts in the mid-twelfth century and late thirteenth century AD and several smaller droughts at irregular intervals before then.  This doesn’t show any particular relationship to the stratigraphic evidence for arroyo-cutting, which seems to have been going on to some degree throughout the period from AD 950 to at least AD 1265.  Furthermore, the evidence for settlement doesn’t line up either.  The marginal nature of the Cowboy Wash area implies that it would probably not have been occupied for most of prehistory, and this was indeed the case.  There were a few ultimately unsuccessful attempts to colonize the southern piedmont, however, and they don’t show any particular relationship to the periods of arroyo-cutting (although they do perhaps relate to periods of drought).  The first agricultural occupation of the area came during the Basketmaker III period, when a few pithouses were apparently used seasonally as summer fieldhouses, presumably associated with nearby fields, from about AD 600 to 725.  After these were abandoned, at a time which may correspond to a drought, the area does not seem to have been occupied again for more than three hundred years.  Then, around AD 1050, a few permanent, year-round sites were built.  These seem to have been occupied for only a few years, however, as there was no significant buildup of trash associated with them.  After they were abandoned, three larger villages, including one at Cowboy Wash, were established around AD 1075.  These had extensive trash deposits and seem to have been occupied for one or two generations.  These communities were apparently abandoned, however, when the next occupation began in the 1120s by a population with apparent links to the Chuska Mountain area to the south.  This occupation at Cowboy Wash is the community that was apparently destroyed around AD 1150 (again coincident with a major drought) when its inhabitants were mutilated and cannibalized.  After this event, the area was once again abandoned until about AD 1225, when two new communities were founded, including one again at Cowboy Wash.  Within a few decades the population at Cowboy Wash appears to have aggregated at Cowboy Wash Pueblo, following a typical pattern for the region.  Also typical of the region, the whole southern piedmont seems to have been abandoned by AD 1280, at the time of the “Great Drought” that coincides with major changes throughout the Southwest.

Entrenched Chaco Wash from Cliff Top near Pueblo Bonito

So basically, all of the attempts at year-round occupation of the southern piedmont seem to have occurred during the period that Cowboy Wash was being downcut.  While these were all ultimately unsuccessful, some lasted for a few decades, so clearly they were able to grow some food at some times.  This strongly implies that at least in this case, arroyo-cutting was not particularly linked to abandoned, although drought probably was.  Huckleberry address the issue of how farming could have been done during periods of downcutting by looking at Cowboy Wash and its tributaries today.  They find that while some portions of the main wash, especially, are indeed heavily downcut, other portions are not, and they label this type of drainage a “discontinuous ephemeral stream,” which is to say, a normally dry wash with some portions that are severely downcut and others that are not.  On the uncut portions, which include much of the length of the tributaries, overbank or ak-chin farming could easily be done today, and this was presumably the case in antiquity as well.  The hydrology of the area is such that the areas of downcutting would not have been stable, and would have tended to migrate upstream, but the complexity of the system is also such that this would not have made the entire system unusable; while some parts were being newly cut, others would be filling in, and prehistoric farmers would merely have to move their fields around a bit rather than abandoning the area entirely.

All that being said, however, the question of why people were trying to settle this quite harsh and difficult area in the first place.  It is interesting to note that the attempts at settlement generally came during periods of relatively favorable environmental conditions, which would have made this area a bit less forbidding than usual, as well as during times of increased regional population, when all the good land may well have been taken and some people were forced to seek out the more marginal areas.  The violence that appears to have accompanied the drought of the twelfth century, especially, suggests that when the good times came to an end social relations got very bad very fast.  Huckleberry and Billman suggest that the reason people did end up abandoning Cowboy Wash, the times when they were not attacked, was merely drought itself, which they were unable to cope with as well as other populations, even those who also used floodwater farming techniques, because the size of the watershed was relatively small and the amount of rainfall feeding the washes was also small, so the total amount of water they had to work with was much smaller even in good times than at place like Chaco with large watersheds.  In that context, even a small decrease in annual precipitation could be devastating, leading to failed harvests and the need to move away.

Non-Entrenched Escavada Wash from New Mexico Highway 57

Indeed, there is evidence that the time of the massacre at Cowboy Wash was very difficult for the people there.  Archaeobotanical studies of pollen and other plant remains showed that there was apparently little or no maize in or around 5MT10010 at the time of abandonment, which is quite surprising for a Pueblo site.  The plant remains that were there were mostly from wild plants such as chenopod, amaranth, and tansy mustard, all of which would have been available in the spring and likely would have been intensively collected if there were no stored corn available due to a failed harvest the previous fall.  In addition to pinpointing the season in which the incident occurred, this implies that times were very tough for the inhabitants of 5MT10010, and perhaps for their attackers too.  The coprolite showed no sign of having plant material in it, which suggests that whoever left it had not just eaten some corn at home before setting out to attack 5MT10010.

Another paper associated with the project, by Patricia Lambert, suggests another problem the Cowboy Wash inhabitants apparently had: disease.  In this paper Lambert reports on analyses of ribs of individuals at 5MT10010 and other sites in the Cowboy Wash area dating to various periods of occupation that had lesions on them suggestive of those seen in modern collections of individuals known to have died of tuberculosis and (to a lesser extent) other respiratory diseases.  These lesions were found in 11 of 32 individuals from Cowboy Wash that had enough of their ribs left to examine.  One of the individuals with lesions was from 5MT10010.  This was an adult woman who was not one of the victims of the attack at site abandonment but who had instead died earlier and been formally buried.  Lambert also examined comparative collections of remains from Pueblo Bonito at Chaco and Elden Pueblo near Flagstaff Arizona.  Only 3 of the 45 individuals from Pueblo Bonito and 2 of the 20 from Eldon Pueblo had similar lesions, suggesting that this disease was much more prevalent at Cowboy Wash than at these other sites, even though it was not absent at them.  Lambert notes that tuberculosis is an opportunistic disease that tends to strike people whose systems are compromised by other problems such as hunger and stress.  The evidence for physical violence in the Cowboy Wash sample, even setting aside the cannibalism assemblages, was much greater than in the other two samples as well.  Combined with the harsh environment, this suggests strongly that Cowboy Wash was a difficult place to live for several reasons.  Farming was possible but risky, and when conditions turned bad both hunger and violence from other hungry people were constant threats.

Given this context, the occurrence of extreme events such as cannibalism incidents at Cowboy Wash starts to make some sense.  Cowboy Wash is a place of extremes.
ResearchBlogging.org
Huckleberry, G., & Billman, B. (1998). Floodwater Farming, Discontinuous Ephemeral Streams, and Puebloan Abandonment in Southwestern Colorado American Antiquity, 63 (4) DOI: 10.2307/2694110

Lambert, P. (2002). Rib lesions in a prehistoric Puebloan sample from southwestern Colorado American Journal of Physical Anthropology, 117 (4), 281-292 DOI: 10.1002/ajpa.10036

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Pueblo Mural at Cortez Cultural Center, Cortez, Colorado

The best-known examples of probable cannibalism in the prehistoric Southwest all cluster in a very short period of time and in a relatively small geographic area: around AD 1150 in the area surrounding the modern town of Cortez, Colorado.  Perhaps the most solidly documented of these assemblages is the one at Cowboy Wash on the southern piedmont of Sleeping Ute Mountain, which has been reported in several publications.  There are sites with reputed evidence of cannibalism that fall outside of these narrow temporal and spatial boundaries, but most of them that have been adequately dated seem to fall earlier rather than later.  In addition to sites like Cowboy Wash where cannibal incidents occurred during the long drought of the mid-twelfth century AD, there are some sites that seem to date to the tenth century, and perhaps the ninth and eleventh as well.

What has not been as well documented is any evidence of cannibalism later, especially during the major drought in the late thirteenth century that coincided with the total abandonment of the Mesa Verde region.  Indeed, the authors of the Cowboy Wash articles note that there is no evidence for cannibalism in the Mesa Verde region after AD 1200.  This is actually rather odd, since environmental conditions during the “Great Drought” of AD 1276 to 1299 were surely at least as bad as those during the twelfth-century drought, and the area had a significantly larger population as well.  If, as many have argued, assemblages like Cowboy Wash were the result of warfare between communities in the region spurred by dwindling resources, it seems logical that there might be similar assemblages from the later drought period.  There is certainly plenty of evidence of warfare and concern for defense.  It could be that whatever it was that inspired some communities in the twelfth century to cannibalize others when attacking them failed to inspire later communities to do the same, even when faced with similar conditions.

Entrance Sign at Canyons of the Ancients National Monument

There is evidence from at least one site, however, indicating that there may actually have been some cannibalism accompanying the warfare of the late thirteenth century.  An article by Kristin Kuckelman, Ricky Lightfoot, and Debra Martin published in 2002 reported on evidence for violence at two sites in Canyons of the Ancients National Monument partially excavated by Crow Canyon Archaeological Center.  One of these, Sand Canyon Pueblo, we have encountered before; it had an enclosing wall that seemed to indicate concern for defense, and as this article relates there were also eight individuals found there who seemed to have died violently, perhaps defending the community from attack.  There was no evidence of cannibalism at Sand Canyon, however, and since very little of this large site was excavated it is hard to tell what the handful of violent deaths signify or whether the attack that apparently killed them led to the abandonment of the community.  It does seem to have occurred around the time of abandonment, which was also the time that the whole region was abandoned, so it would make sense if the end of Sand Canyon Pueblo came violently.

The other site, however, was rather different.  This was Castle Rock Pueblo, a smaller site a few miles from Sand Canyon.  Here at least 41 individuals who died violently were found, at a site that probably only held about 15 households total with a total population of maybe 75.  Since only a small portion of the site was excavated and yet remains representing at least half of the probable number of site residents were found, it is very likely that the entire site was destroyed, and all its residents killed or captured, in a raid at the end of site occupation, sometime around AD 1280 or 1285.  In addition, many of the bones found showed clear evidence of processing similar to that found at Cowboy Wash and other twelfth-century cannibalism assemblages.  This implies that at least some of the victims of the raid were eaten, although the lower number of processed bones relative to the total number of bones suggests that this was only done with some portion of the dead, which may mean that starvation would not have been the main motivation behind the cannibalism in this case.  Several tools and pottery vessels at the site also tested positive for human myoglobin, using similar methods to those used to identify the contents of the coprolite at Cowboy Wash, again strongly suggesting that they were used to process and cook human muscle.  All this suggests that cannibalism was in fact practiced after AD 1200 in the Mesa Verde region, at least at this one site.  Since no other site from this period has shown evidence of cannibalism, however, even though evidence of warfare is common, it seems to have been an unusual occurrence, which does still leave the difference between the numerous incidents of cannibalism during the twelfth century and this isolated one during the thirteenth as an open question.

Debra Martin was one of the authors of the critique of the initial Cowboy Wash article, and she seems to have been responsible for the parts of the critique that addressed the analytical methods and data reporting in the article.  Since she was also a coauthor on the Castle Rock article, it serves as a useful glimpse of what she meant in the critique.  The tone and structure of this article are very different from the Cowboy Wash one.  The tone is restrained, with the word “cannibalism” used sparingly and often replaced by “anthropophagy” (which means the exact same thing but sounds more technical and scientific), and a footnote discusses Crow Canyon’s consultation with its Native American advisory group and notes the objections some members of the group had to the publication of the article.  The reporting of the data and analysis is very careful and thorough, and the text pointedly mentions that this is for the benefit of other scholars, to allow them to evaluate the information for themselves.  The article never explicitly contrasts this with the approach of the Cowboy Wash team, but the implicit reproach is obvious.

Sleeping Ute Mountain from Yellow Jacket Pueblo

This article also includes a useful discussion of who the attackers might have been.  It is generally thought that other Puebloan groups rather than other cultural groups, such as nomadic hunter-gatherers, were responsible for attacks like this, and the authors of this study generally agree, although they do note the presence of a projectile point of a non-local type from east-central Utah as one possible piece of evidence for a cultural difference between attackers and victims.  They then discuss which communities in the Mesa Verde region would still have been populous in the 1280s to defeat Castle Rock, which was a relatively small pueblo but was in a pretty defensible location and would have taken a fairly large force to overrun.  They conclude that Sand Canyon, Yellow Jacket, Mesa Verde proper, and possibly Hovenweep were still occupied at the time, and that any of them could conceivably have been the attackers.  They also note that groups from outside the region, especially in the Kayenta area to the southwest and the Totah area to the south, could have been involved, either on their own or in alliance with local groups.  Figuring out which of these groups was actually to blame is tricky, however.  With the twelfth-century cannibalism sites there is a division between “victim sites” like Cowboy Wash, where people were apparently cooked and eaten at the location that had been attacked, and “perpetrator sites” where bodies were brought from sites that had been raided and eaten at the attackers’ home base.  Castle Rock is clearly a victim site, but since it is the only known cannibalism site dating to this period no known perpetrator sites that might reflect the attackers have been identified.

One of the major contributions of this paper, in addition to documenting thirteenth-century cannibalism in the Mesa Verde region, is in specifically tying cannibalism to warfare.  In most documented cannibalism assemblages, including at Cowboy Wash, the bones have been so heavily processed that any evidence of the cause of death is obliterated, so it can be impossible to tell if the victims died violently or died some other way and were then eaten, perhaps by starving members of their own communities.  Since the Castle Rock assemblage contains many instances of violent death without apparent cannibalism, in addition to some examples of cannibalism, all of this having happened at the same time, it makes a strong case that cannibalism was in fact associated with warfare during this period, which in turn implies that it probably was during the twelfth century as well.  This is an important finding in the attempt to figure out what these gruesomely enigmatic sites mean for the prehistory of the Southwest.
ResearchBlogging.org
Kuckelman, K., Lightfoot, R., & Martin, D. (2002). The Bioarchaeology and Taphonomy of Violence at Castle Rock and Sand Canyon Pueblos, Southwestern Colorado American Antiquity, 67 (3) DOI: 10.2307/1593823

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Sleeping Ute Mountain from Cortez, Colorado

In comments to the previous post, Graham King raises an important question: assuming that the assemblages of broken, burned, and otherwise unusually treated bones at sites like 5MT10010 at Cowboy Wash represent incidents of cannibalism, what does this mean culturally and historically?  After all, cannibalism has occurred in various contexts in many societies, including our own, and it can arise from a variety of causes.  One of the most obvious is starvation, seen most often in situations like the plane crash in the Andes made famous in the movie Alive and incidents during the settlement of the American West such as the Donner Party and the Alferd Packer case, all of which involved small groups being trapped in mountains under harsh conditions and resorting to cannibalism to survive.

So were the events at Cowboy Wash around AD 1150 the result of survival cannibalism, perhaps of members of the community who had died due to disease or starvation by other members of the community?  The excavators of 5MT10010 argued that they were not, but the evidence they gave for this conclusion is not particularly convincing.  They basically had two arguments against survival cannibalism:

  • If the individuals at Cowboy Wash had died natural deaths, the demographics of the dead should reflect the differing susceptibility to harsh conditions of different age groups, which generally means a higher death rate among infants and a lower one among older children and adolescents.  Since the 5MT10010 assemblage contained no infants but a higher than expected number of older children, it is unlikely to have resulted from natural death.
  • Unlike in the historically documented cases, the people at Cowboy Wash were not physically trapped.  There was nothing preventing them from moving away from the area if there were insufficient resources.  The southern piedmont of Sleeping Ute Mountain is pretty flat and open, rather than mountainous, and the abandonment of the sites there apparently took place in the spring, when snow would not have been an issue.

Neither of these arguments is very convincing.  The assemblage of cannibalized individuals at 5MT10010 looks demographically unusual, sure, but then again it apparently consists of only seven people.  That’s a minimum number, of course, but since the whole site was excavated and it wasn’t a large site to begin with it seems likely that the recovered bones represent most or all of the people involved.  If the assemblage represents the inhabitants of the site, which the excavators claim and I see no reason to doubt, they likely represent a family or other social unit, and it’s quite possible that they just didn’t happen to have any infants in the group at the time of the event.  In any case, with a population this small there is no reason to expect any sort of “normal” demographic profile.

The second argument is better, but still somewhat unconvincing.  It’s definitely true that the inhabitants of Cowboy Wash wouldn’t have been snowed in at the time of the abandonment event, which apparently took place in the spring, but it’s not necessarily true that they would have had somewhere else to go.  This was a time of drought and resource shortages throughout the northern Southwest, and there is considerable evidence for violence (even leaving aside the alleged cannibalism incidents) throughout the region, including at other sites in the Ute Mountain area, at the time.  Indeed, Cowboy Wash is a very marginal area for agriculture to start with, so the fact that they were there in the first place, and that they had not already left when the harvest failed, implies strongly that they had nowhere else to go.  Under those circumstances, it is certainly conceivable that some community residents might have begun to succumb to hunger or disease and others in the community may have resorted to eating them.  That’s not to say that it’s likely or the best explanation, of course.  One piece of evidence arguing against this interpretation, which the excavators mention but don’t go into much detail on, is that all the processing seems to have taken place at the same time, rather than drawn out over a period of weeks or months as might be expected if people were gradually dying and being eaten.

Sleeping Ute Mountain from Lowry Pueblo

Instead of survival cannibalism, the Cowboy Wash excavators prefer a scenario of intercommunity violence to explain the 5MT10010 assemblage.  This implies that the people who ate the residents of 5MT10010 also killed them.  This sort of explanation does fit well with the other evidence for violence short of cannibalism in the region during this period, but it is tricky to show any correlation between violent death and cannibalism because the processing of the bodies would likely eliminate any skeletal evidence of violent death.  That does seem to be the case in this assemblage, as in most other alleged cases of cannibalism.  There’s plenty of evidence of skeletal trauma, of course, but most of it seems to be directly related to the processing of the bodies shortly after death, and much of the rest seems to represent injuries incurred during life that had healed before death.  In this case, then, there is no direct evidence linking alleged cannibalism to violent death.

One piece of evidence supporting the “raid by other group” theory is that three other sites in the Cowboy Wash community, contemporary with 5MT10010, have also been excavated and all three show similar signs of cannibalism.  Since there are only ten sites in the whole community, the fact that four of them seem to have been rapidly abandoned at the same time that many people in them were eaten seems to imply that the abandonment was the result of a single event.  As the authors of the 5MT10010 paper point out there and in more detail in another article, however, there are some differences among the four assemblages and even between the assemblages in the two pitstructures at 5 MT10010 containing large numbers of bones.  Although all four sites show evidence of processing for consumption, the specific body parts that are most prevalent and the way they were processed suggest that the processing was done separately at each site and not in accordance with a common technique.  For example, at 5MT10010 the bodies found in one pitstructure appeared to have been cut into small pieces and cooked in a pot on the surface, with the bones thrown down the ventilator shaft after consumption.  At the other pitstructure, however, the bodies seem to have been cut into fewer pieces and roasted directly on a fire in the hearth inside the structure.  All this suggests that if in fact the Cowboy Wash community was destroyed by a raid, the raiders who attacked each part of it seem to have acted fairly autonomously in deciding how to deal with the inhabitants, even though they all apparently had the common goal of eating them.

This is actually rather odd, and does seem to undermine the idea that warfare was behind the cannibalism at Cowboy Wash.  It is possible, however, that raiding and survival cannibalism aren’t mutually exclusive, and that the raiders of Cowboy Wash may have attacked it specifically in order to eat the people there because they themselves were starving.  The excavators do mention that the meat from a cannibalistic attack may have been a valued “spoil of war” during harsh environmental times like this, but they generally downplay this aspect and focus more on the idea that cannibalism would have served as a terroristic tactic to strike fear in the hearts of enemies and perhaps scare them away from the area.  (The two are not necessarily mutually exclusive, of course.)  The fact that the people in the different parts of the Cowboy Wash community were apparently prepared differently does seem more compatible with the idea that the attackers were focused on eating them because they were hungry than with the idea that they were concerned with striking fear into any survivors or other nearby villages.  The terroristic theory seems to imply a ritualistic approach to the cannibalism, which is not particularly apparent in this or any other Southwestern cannibalism assemblage.  Any type of ritual cannibalism would likely have been more standardized in execution, as in Mesoamerica where ritual cannibalism was widespread.  In the Southwest, by contrast, the execution seems rather haphazard.

So, tentatively, I think the best explanation at least for Cowboy Wash specifically, and perhaps for other cases as well, is that certain communities in the Mesa Verde area during the extended drought of the mid-twelfth century AD hit upon the idea of compensating for their poor harvests by attacking other communities, not to take their stored food (since they likely didn’t have any either) but to eat their residents.  Which communities these might have been and where they got the idea remain open questions.  This idea led to a rash of cannibalism incidents around AD 1150 which subsided soon thereafter, perhaps as climatic conditions improved (or, alternatively, as other communities got better at defending themselves).  When the next major drought came, in the late thirteenth century, the idea of cannibalistic raiding does not seem to have been taken up again.  The authors of the Cowboy Wash articles take pains to note that there is no evidence of cannibalism in the Mesa Verde area after AD 1200.  Although there is plenty of evidence of violence during the late 1200s preceding the total depopulation of the region by 1300, none of this involved cannibalism.

Or did it?  There is actually some evidence from at least one site suggesting that the idea of cannibalism did not totally disappear from the Mesa Verde area after 1200.  But that’s a matter for another post.
ResearchBlogging.org
Lambert, P., Billman, B., & Leonard, B. (2000). Explaining variability in mutilated human bone assemblages from the American Southwest: a case study from the southern piedmont of Sleeping Ute Mountain, Colorado International Journal of Osteoarchaeology, 10 (1), 49-64 DOI: 10.1002/(SICI)1099-1212(200001/02)10:13.0.CO;2-B

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Sleeping Ute Mountain from Mule Canyon, Utah

In their critique of the article reporting evidence for alleged cannibalism at site 5MT10100 near Cowboy Wash on the southern piedmont of Sleeping Ute Mountain, Kurt Dongoske, Debra Martin, and T. J. Ferguson challenged many of the conclusions and lines of evidence presented in the article.  Among these was the evidence of consumption of human flesh from a coprolite found in a hearth at the site, which could potentially serve as the “smoking gun” offering physical proof of cannibalism, if the analysis is correct.  The authors of the critique found the presentation of this evidence in the initial article unconvincing, however, describing the data as “sketchy” and implying a lack of scientific rigor in the analysis.  They concluded this section of the critique by saying:

We are not microbiologists, and therefore before accepting the claim that the coprolite contains human myoglobin, we await peer review and publication of the fecal study by Science or another scientific journal specializing in biomolecular research.  As presented in the Cowboy Wash study, the fecal evidence is suggestive but not convincing. More work pursuing this line of evidence is warranted in future studies.

In their response to the critique, the authors of the original paper added more detailed information on the coprolite analysis, but they also did as the critique authors recommended and published a short article in Nature (Science‘s main competitor) giving more specific details on the analytical techniques used to detect human myoglobin both in the coprolite and on some potsherds from a cooking vessel found in the same pitstructure.  There isn’t actually much in this paper that wasn’t in the response to the critique, aside from the laboratory procedures, which I am not in a position to evaluate.  It’s not actually clear to me if this article was peer-reviewed; it doesn’t explicitly mention any reviewers or any details of the review process, but this doesn’t necessarily mean it wasn’t reviewed.  It’s also not clear to me if the authors submitted it in response to the critique or if they had already intended to.  Both the original article and the critique were published in January 2000, and this article was received by Nature on March 7,  accepted on June 6 (which does seem to imply some sort of review process), and published on September 7.  Meanwhile, the response to the critique was published in April.  In any case, whether or not the authors of the initial paper were spurred by the critique to submit additional publications (and this is not the only one to appear after the critique was published), they certainly can’t be accused of shrinking from the challenges it set for them.

Mentioning this paper also allows me to go into a bit more detail about the myoglobin analysis, which I didn’t in the previous post.  Basically, to determine if the coprolite resulted from the consumption of human flesh the researchers needed to find something to test for that would be present in parts of a human body likely to be consumed but not in parts of the consumers body likely to end up in the coprolite during the digestion process  (e.g., blood or intestinal lining).  They decided on myoglobin, which is a protein molecule in the skeletal and cardiac muscles that transports oxygen from the outer membrane of muscle cells to the interior parts of the cells where it is used to generate energy.  Importantly, this protein is not found in the smooth muscles of the digestive system or in the blood, so it is unlikely to end up in fecal matter as part of the digestive process.  The researchers used a variety of controls to establish this, including coprolites from Salmon Ruin and modern fecal samples from “normal individuals,” people with blood in their stool, and people who had recently eaten beef.  None of these ancient or modern samples tested positive for human myoglobin, but the beef ones did test positive for bovine myoglobin, establishing that myoglobin can indeed be found and identified to species in fecal material.  These controls were mentioned in the original article, and when I read it I had wondered where they had gotten the modern samples.  The Nature article explains that they came from leftover material from clinical samples that was turned over for research use, which makes sense.  For the sherd testing, the controls were other sherds from the same site, sherds from another site in Southwestern Colorado dating from the same period but without evidence of cannibalism, and sherds from a Plains site near Denver also dating to roughly the same period.  None of these control sherds tested positive for human myoglobin either, although some tested positive for deer or rabbit myoglobin.  Thus, since the coprolite from Cowboy Wash and the sherds found near it were the only samples to test positive for human myoglobin, the hypothesis that they were associated with ingestion of human flesh was not disproven, and it remains the most plausible explanation of the Cowboy Wash assemblage.

It’s certainly possible that problems may be found with this analysis that cast doubt on the result, but I haven’t seen any, and until I do I’ll provisionally accept it as indicating very strongly that broken and burned bone assemblages like the one at Cowboy Wash most likely result from cannibalism.  What that might mean culturally and historically, of course, is a different and more difficult question.
ResearchBlogging.org
Marlar RA, Leonard BL, Billman BR, Lambert PM, & Marlar JE (2000). Biochemical evidence of cannibalism at a prehistoric Puebloan site in southwestern Colorado. Nature, 407 (6800), 74-8 PMID: 10993075

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Peñasco Blanco

Near the very end of his report on the excavations at Pueblo Bonito by the Hyde Expedition in the 1890s, George Pepper wrote the following:

The finding of cracked and calcined bones in some of the rooms brings up the question of the eating of human flesh by the people of this pueblo.  There was no evidence of human bodies having been buried in rooms above the first floor and only portions of skeletons were in evidence in Rooms 61 and 80 which contained broken and charred bones.  During the period of our work in Pueblo Bonito some of our Navajo workmen cleaned out a number of rooms in Penasco Blanco and in one of these a great many human bones were found.  Some of these including portions of the skull, were charred, and the majority of the long bones had been cracked open and presented the same appearance as do the animal bones that have been treated in a similar way for the extraction of the marrow.  It would therefore seem that these Pueblo Indians, either through stress of hunger or for religious reasons, had occasionally resorted to the eating of human flesh.

The report was published in 1920, and ever since then the question of cannibalism has hung over Chaco Canyon like a giant question mark.  In the 1920s Frank Roberts found some additional bones at another site at Chaco that were in a similar condition, but these and the ones mentioned by Pepper constitute the entire sample of bones from Chaco itself that have been proposed as evidence for cannibalism.  On its own, this is pretty weak stuff, especially since it comes only from sites that were excavated early in the history of archaeological research at Chaco and information on the context of these bones is very limited.  Most archaeologists have therefore generally been content to conclude that whatever these bones represent, they don’t have much relevance to explaining Chaco as a whole.

Over the decades since Pepper wrote his report, however, a growing number of other sites throughout the northern Southwest have revealed human bones that are broken, burned, and otherwise suspiciously unlike typical burials.  As archaeological techniques have improved, the amount of information about the context of these finds has increased, and as physical anthropologists have gained experienced and added new techniques more information can be gained from both these new finds and the early ones now in museums.  One physical anthropologist in particular, Christy Turner of Arizona State, has put an enormous amount of effort into analyzing evidence for cannibalism in the prehistoric Southwest.  His overall interpretation of the evidence has led him most recently to propose, particularly in the 1999 book Man Corn, coauthored with his wife, that cannibalism was a core part of the Chaco system, which he sees as a militaristic state led by some sort of sociopathic Toltec leader who came up from Mexico and attempted to institute a Mesoamerican state based on tribute and human sacrifice, or something (I haven’t read the book).

Sleeping Ute Mountain from Anasazi Heritage Center

Obviously this theory depends heavily on attempts to equate the evidence for cannibalism across the Southwest with the rise of Chaco, and here it immediately runs into problems.  While there is the evidence from Chaco reported by Pepper and Roberts, most of the evidence for cannibalism in the Southwest comes from contexts that are rather distant from Chaco both spatially and temporally.  Some are earlier, particularly in the AD 800s and 900s, when the Chaco system may have been gearing up but was certainly not yet in the culturally dominant role it attained by the late 1000s.  More are later, mostly in the AD 1100s, after Chaco’s influence declined.  Spatially, most of the well-documented examples from recent examples are from southern Colorado, which was certainly under Chacoan influence at one point but probably was not at the times the events apparently occurred.  Indeed, most of these well-documented examples are from a strikingly specific time and place: around AD 1150 in the area around Sleeping Ute Mountain, west of the modern town of Cortez, Colorado.  There are other examples known from New Mexico and Arizona, but like the Chaco examples they mostly come from poorly documented early excavations and can’t be placed very well temporally.

According to one count, there are 32 sites in the Southwest that have yielded bones that may indicate cannibalism.  Of these, 18 are in the greater Mesa Verde region in southwestern Colorado and southeastern Utah and can be dated with some certainty.  Fully half of these sites, 9 out of 18, date to between AD 1125 and 1175.  This striking spatial and temporal patterning has led some to suggest that these may reflect a single event of some sort that occurred in the context of the multidecadal drought of that period and the social disruption caused by the decline of the Chaco system at the same time.  This idea was proposed in a talk I attended at the 2009 Pecos ConferenceSeveral names were on the talk, including Turner’s (although he didn’t seem to actually be there), but much of the actual talking was done by David Breternitz, an archaeologist with long experience with the region.  In addition to proposing that these assemblages indicating cannibalism or at least “folks treated inconsiderately” represented a single event that may have taken place over the course of mere weeks, days, or even hours, Breternitz noted the problematic connotations of using the word “cannibalism,” which has made the study of these sites a lightning rod for controversy as well as an irresistible temptation for sensationalistic treatments in the popular press.  He referred to it as the “C word” and analogized it to the “N word,” which is not appropriate to use in talking to the NAACP (or, I would add, most other audiences).

Sign at Border of Ute Mountain Indian Reservation

Both the puzzling and the controversial aspects of the cannibalism issue are present in the case of one of the best-documented of these assemblages in the Cortez area.  This is that found at site 5MT10010 near Cowboy Wash on the southern piedmont of Ute Mountain, which was excavated as part of a salvage operation in connection with an irrigation project of the Ute Mountain Ute tribe, on whose reservation the site is located.  This site, which was described in an article in American Antiquity in 2000, was located in an area that was slated to be completely covered by a new irrigated field and was therefore completely excavated.  It consisted of three pitstructures, like kivas but of clearly residential function, with associated surface masonry rooms, which do not seem to have been used residentially, outdoor activity areas, and trash middens.  Two of these pitstructures contained assemblages of human bones that were heavily damaged and broken into hundreds of small pieces, some of which showed burning, cut marks, and other evidence of cannibalism similar to that found at other sites.  These apparently represented the remains of seven individuals: two adult males, one adult female, one adult of uncertain sex but probably male, and three youths of uncertain gender aged approximately 14, 11, and 7.  Their bones were strewn all over the two pitstructures and showed no grave goods or evidence of formal burial, in striking contrast to five individuals who had been formally buried in the trash mounds (which is a typical burial location for this area and period).

From the way the bones were broken and burned the authors concluded that all of the individuals in the pitstructures had been killed in a sudden attack at the same time, after which they were cooked and eaten and the site was totally abandoned and not reoccupied.  In addition to the cut marks and burning on the bones themselves, two stone tools found in one of the pitstructures tested positive for human blood, implying that they had been used to chop up the bodies.  Evidence for the sudden nature of the attack and the resulting abandonment consisted largely of the large number of artifacts left in place in all three pitstructures; normally when a site would be abandoned the people would take most of the usable artifacts with them, but in this case they were left in place.

As if all this wasn’t enough, the third pitstructure, which didn’t contain any bones except two which were heavily weathered and appeared to have been deposited naturally from the surface at some point after abandonment, did contain something even more interesting: a coprolite, unburned, in the hearth.  Analysis revealed that the coprolite was human, apparently resulted from a meal consisting entirely of meat, and tested positive for the presence of a human muscle protein.  This is about as close to smoking gun as it is possible to get in trying to establish if cannibalism took place in a given instance.  Cut marks on bones can be and have been explained in various other ways, which are not generally very convincing but hard to disprove.  This coprolite, however, seems to establish clearly that at least in this one instance, cannibalism did take place.

Sleeping Ute Mountain from Hovenweep National Monument

The authors, having established to their satisfaction that this assemblage does in fact represent an episode of cannibalism, went on to situate it in the context of both the local community and the larger region.  The regional analysis basically pointed out the rash of likely cannibalism episodes around AD 1150, which may have been associated with the drought of that period, although it also noted the earlier episodes and the likelihood that this behavior constituted a longstanding pattern that for some reason became briefly intense and then subsided.  They note that there is no evidence for cannibalism in the Mesa Verde area after AD 1200 (though this may not actually be true; more on that later) and very little evidence anywhere else in the Southwest after that date either.  Whatever this event represents, it was clearly pretty temporary.

The community analysis was particularly interesting.  This community on Cowboy Wash, which was established around AD 1125 and consisted of 10 sites, four of which have been excavated.  Strikingly, all four of the excavated sites showed the same sort of evidence of cannibalism, strongly implying that they were all attacked and destroyed at the same time around AD 1150.  This is in contrast to the earlier community at Cowboy Wash, which existed from about AD 1075 to sometime in the 1120s and was abandoned before the new one was established, probably by new people.  Another striking characteristic of the newer Cowboy Wash community was the prevalence of ceramics made in the Chuska Mountain area to the south along the Arizona-New Mexico border.  Chuska pottery was common at Chaco during its prime and has been found in various other areas as well, but it is extremely rare in the Mesa Verde region and the prevalence of it at Cowboy Wash strongly suggests that the inhabitants were either immigrants from the Chuskas themselves (pretty plausible in the light of the disruptions likely associated with the fall of the Chaco system, with which the Chuska communities were strongly associated) or maintained strong trading ties to Chuska communities rather than other local communities.  Either way, the inhabitants of this community would likely have been easily identified as “outsiders” in the area, which may explain why they were targeted by others during this time of scarce resources, extended drought, and increased violence.  The Cowboy Wash community was not in a defensive location and does not appear to have had any defensive features such as walls.  Its fate may explain why such locations and features became so common not long afterward.

Chuska Mountains from Peñasco Blanco

Of course, with something like this there will always be objections, and a critique of the claim of cannibalism by two archaeologists who have been closely identified with the interests of the modern Pueblos, Kurt Dongoske and T. J. Ferguson, along with physical anthropologist Debra Martin, accompanied this article when it was first published.  The three of them basically criticized everything they could about the presentation of data and argumentation in the article on the Cowboy Wash site.  Some of the criticisms were reasonable, including a caution about being too quick to talk about cannibalism and to keep in mind the likely effect of this in the popular press and on modern Native Americans.  Others basically amounted to nitpicking about the presentation of data, often appearing to demand a level of information more appropriate for a full site report than a journal article.  In a response, the authors gave more information on the analysis and tried to counter accusations that the blood residue and coprolite analyses in particular may have been contaminated or otherwise problematic.  They also conceded some of the points raised in the critique, especially about the importance of thinking about the effect of this kind of research and the way it is presented in public discourse.  This response seemed pretty convincing to me.  I’ve heard that the coprolite evidence in particular has been challenged, but I’m not sure if any more substantial objections than the easily defused ones in the initial critique have been raised.

Another interesting thing about the critique and response, to me, is the way the critique basically accuses the authors of the initial article of being insufficiently “scientific” in not rigorously testing alternative hypotheses.  This is interesting largely because it clearly falls on the “anthropology is and should be a science” side of the “is anthropology a science?” debate, even though these particular anthropologists are coming from a perspective that is usually associated with the other side in their close association with the modern Pueblos and appreciation of their viewpoints.  In this context they seem to be mostly raising the science issue as a club with which to (rather ineffectively) attack the initial article, but the use of this approach is still noteworthy.  The response basically runs with this assumption and argues that, no, the analysis really was very scientific and they didn’t include all the data and hypotheses because of the space constraints of the journal article, but it’s all in the full report.  Both seem to think of “science” mostly as a methodology, particularly associated with hypothesis testing, rather than a body of knowledge, which is also interesting.

Another thing the critique mentions is the desirability of more comprehensive approaches to the issues of violence, migration, warfare, and so on.  The critique authors say this in the context of criticizing the initial report for focusing too narrowly on cannibalism specifically, which sits oddly with their criticisms of it for not being specific enough in describing the physical evidence, but this is one of their better points.  They specifically mention the possible role of ethnicity in structuring some of these dynamics, and cite the paper on ethnicity at Wupatki by Glenn Davis Stone and Christian Downum that I recently discussed.  I know of at least one recent paper that has done just that; I’ll have more on it later.

Sleeping Ute Mountain from Four Corners

So what does all of this imply for Chaco? Not much, really.  The authors of the initial Cowboy Wash paper note that to the extent that the Cortez-area spate of cannibalism episodes around AD 1150 has anything to do with Chaco, it is most likely in representing one aspect of the social chaos that may have followed the decline of the Chaco system after AD 1130 or so.  They also note that Cowboy Wash is about as far from a Chacoan outlier as it was possible to get in the region during this period.  The closest proposed outlier is Yucca House, on the other side of Sleeping Ute Mountain toward Cortez, the outlier status of which is rather questionable since it is unexcavated and also has a large later occupation that makes it difficult to identify any Chacoan parts.  And speaking of the location of Cowboy Wash, it is important to note that the southern piedmont of Sleeping Ute Mountain is remarkably desolate even by Southwestern standards and would have been very marginal for agriculture.  It doesn’t get enough rain for dry farming, so any farming the people at 5MT10100 would have done would have to have been floodwater farming using the wash itself, which would be very vulnerable to fluctuations in rainfall and other climatic conditions.  This probably explains why the area was colonized and abandoned several times during prehistory.  The time of the attack appears to have particularly bad for the inhabitants, as there was minimal evidence of domestic plants and most of the plant remains found at the site were of wild plants that would have been gathered in the spring to compensate for a poor harvest in the fall.

And what about the bones mentioned by Pepper at Chaco itself?  Hard to say.  Turner has reexamined some of them and concluded that they do in fact represent evidence of cannibalism, but then again he would conclude that.  The fact that we don’t really have any more detailed information about their contexts within the site than the minimal information given by Pepper makes it very difficult to place them within the context of Chacoan prehistory as we know it today.  Judging from the better information we now have from Colorado, I think one possibility is that the Chaco bones represent something similar that happened around the same time.  The canyon was not totally abandoned after it declined in regional importance around 1130, and it might have participated in some way in the cannibalistic warfare that apparently took place after that, though whether as victim or perpetrator is hard to say.  Whether or not this is the actual explanation, it is important to remember that the fact at a big, complex site like Pueblo Bonito not everything found somewhere in the is necessarily closely connected to the original purposes for which the site was built.  Things change, after all.  Furthermore, Pueblo Bonito has hundreds of rooms, almost all of which have been thoroughly excavated, and possible evidence of cannibalism has been found in two.  That’s a pretty thin reed on which to hang a theory postulating that Chaco was all about cannibalism.  Some cannibalism may well have taken place at Chaco, but there is really no reason to think that it was a major part, or indeed any part, of the reason Chaco was built or became so influential.  At least, that’s the way I see it.  Merry Christmas.
ResearchBlogging.org
Billman, B., Lambert, P., & Leonard, B. (2000). Cannibalism, Warfare, and Drought in the Mesa Verde Region during the Twelfth Century A.D. American Antiquity, 65 (1) DOI: 10.2307/2694812

Dongoske, K., Martin, D., & Ferguson, T. (2000). Critique of the Claim of Cannibalism at Cowboy Wash American Antiquity, 65 (1) DOI: 10.2307/2694813

Lambert, P., Leonard, B., Billman, B., Marlar, R., Newman, M., & Reinhard, K. (2000). Response to Critique of the Claim of Cannibalism at Cowboy Wash American Antiquity, 65 (2) DOI: 10.2307/2694066

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"Stay off the Walls" Sign at Chimney Rock Pueblo

Sand Canyon Pueblo, which I discussed in the previous post, is one of the best-known prehistoric communities in the Southwest due to the multi-year research program conducted there by Crow Canyon Archaeological Center in the 1980s and 1990s.  Crow Canyon selected it for this research for a variety of reasons, including its short period of occupancy and its status as a typical example of a “canyon-head village,” a common settlement type in the Northern San Juan region during the thirteenth century AD.  One of the highly characteristic features of a canyon-head village that Sand Canyon has is the site-enclosing wall which extends around almost all of the architecture at the site.  As Bruce Bradley noted in the 1993 paper that I discussed earlier, this wall seems to have been built as a communal effort early in the occupation of the site, perhaps at the very beginning, and the other parts of the site that have been excavated were built into the space already enclosed by the wall.  The wall thus served to define the boundaries of the community and to determine where subsequent construction could occur.

This appears to have been one of the main purposes of walls in the Northern San Juan region more generally.  In 1997 Susan Kenzle published an article surveying information available about walls at a wide variety of communities in this region.  Based on published reports on 88 sites, 41 of which have walls and 47 of which do not, she did some statistical tests of various other features of the sites and came up with some proposals for the functions of the walls in the villages that had them.  The two main categories of functions she proposed were “sociophysical boundaries” and defensive fortifications.

Adobe Wall around House in North Valley, Albuquerque, New Mexico

Under “sociophysical boundaries” Kenzle basically subsumes a variety of functions of walled or enclosed space, based largely on the environmental psychology literature.  These mainly revolve around control of who can access a community and what they can do there, particularly in the context of separating “insiders” (i.e., residents of the community) from “outsiders” (e.g., peaceful visitors coming to trade or enemies attacking).  Restricting access to and information about the resources in the community, such as food stores or water sources would be one major purpose for trying to control access this way.  Ensuring privacy for the residents, which may have become increasingly important as previously dispersed communities began to aggregate into dense villages during this period, is another possible reason.  Kenzle notes that in many societies, including our own, walls or fences associated with individual dwellings can serve to increase privacy for households living close proximity.

Another obvious purpose of walls like the one at Sand Canyon is as defensive fortifications, and Kenzle devotes considerable attention to this idea.  She evaluates the plausibility of a defensive interpretation of the walls at these communities by looking at the research on defensive fortification in general and finds that the walls do indeed meet many of the criteria identified for effective fortifications, especially in combination with other community characteristics such as defensible locations (including canyon heads and rims) which correlate in her sample with presence of walls.  Specifically, many of the walls were high enough to serve as effective cover for defenders while also serving as obstacles for attackers, and they also tend to have few openings, which reduces the number of ways in available to attackers and makes it easier for defenders to guard the entrances to the community.  There are a few arch-shaped projections in walls that may have served as bastions, allowing defenders to fire on attackers from the side in addition to the front.  There is also one example, at Sand Canyon, of possible loopholes through which defenders could have fired unseen, although is is unclear if this is what these holes were actually for.  While this is apparently the only known example of possible loopholes in the Northern San Juan, I know that there are some other possible examples elsewhere in the Southwest.  There are apparently some alleged loopholes at Wijiji in Chaco Canyon, although I’ve never noticed them myself.  There are also small holes in the walls of various other sites in the region which could possibly be loopholes, although it can be difficult to tell these from vents or holes for roof beams.

Square Tower, Hovenweep National Monument

Other aspects of defensive systems involving these walls include the numerous towers found throughout the region at both walled and unwalled communities from the twelfth and thirteenth centuries and protected water sources, also typical of these communities.  Kenzle also summarizes the extensive evidence from a variety of sources for violent conflict in the Northern San Juan during this period, which further supports the idea that the walls were largely defensive.  The people certainly had something to defend against.

Whether the walls were successful at defending the communities is a different matter, and one Kenzle doesn’t really address.  It’s worth noting that some of the walled communities, Sand Canyon included, show evidence of violent death suggesting that they experienced successful attacks which in some cases seem to have ended site occupation entirely.  It’s also noteworthy that after the Northern San Juan region was abandoned entirely around AD 1300 the wall tradition does not seem to have been carried on by the people who left the region for other parts of the Southwest such as the Rio Grande Valley, where the preferred form of defensive settlement pattern seems to have involved massive sites with enclosed plazas surrounded by roomblocks with little or no exterior access.  This pattern was carried on well into the historic period, so it seems to have been fairly successful, although there are still examples of communities like this this being successfully attacked.  Kenzle does note that the more recently occupied pueblos of Pecos and Taos both have walls.  In the case of Pecos she implies that the function of the wall may have been more symbolic as a social boundary than practical as a defensive feature.  In the historical period members of Plains tribes who came to trade at Pecos were not allowed to spend the night within the wall, a social boundary that they apparently respected but also presumably a defensive precaution.  At Taos the wall apparently dates to the eighteenth century and was initially defensive, used for fending off Comanche raids.  Interestingly, it also apparently had loopholes.  After defense was no longer such a concern the wall was reduced in height and began to serve as more a symbol of Taos culture and a boundary meant to metaphorically defend that culture from Anglo influence.  In both cases it is unclear if there is any continuity between these walls and the earlier ones in the Northern San Juan.  None of the other modern Pueblos have walls.

Back Wall of Wijiji

This paper is an interesting examination of a topic that had not previously been given much attention, despite its importance to a variety of other issues in Southwestern archaeology, including the aggregation of communities, the abandonment of large areas, and the role warfare may have played in these processes.  The strength of Kenzle’s conclusions is limited by the poor quality of much of the information on the sites in question, but that is a constant issue in Southwestern archaeology and she takes it into consideration by being appropriately tentative about her conclusions.
ResearchBlogging.org
Kenzle, S. (1997). Enclosing Walls in the Northern San Juan: Sociophysical Boundaries and Defensive Fortifications in the American Southwest Journal of Field Archaeology, 24 (2) DOI: 10.2307/530471

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Sign for Building Permits, Planning, and Zoning, Winslow, Arizona

When I was working at Chaco and would tell visitors that I was going to graduate school for city planning, most people would remark on what a difference that sounded like.  And, indeed, there are a lot of differences between my life when I was at Chaco and my life here at school in New Jersey.  There’s a considerable amount of continuity, however, between what I learned there and what I am learning here.  Archaeologists and planners actually deal with many of the same issues, just in very different contexts.  Land use and the interactions between people and their environments are among the topics that are at the core of both fields of study.  And yet, the two rarely meet.  It’s like they are operating in parallel, looking at the same issues but evaluating them with different methods and often coming to different conclusions.

On the rare occasions when archaeologists and planners talk to each other about their shared interests, it generally seems that archaeologists are by far the more thoughtful and serious about them.  There’s a real sense of superficiality about most of the planning theory I’ve been learning about in this program, which is perhaps unsurprising given that the profession is more action-oriented and focused on practical solutions than archaeology, which takes a more detached, descriptive, academic approach.  Nevertheless, I’ve come to believe that acting decisively on limited information and poorly considered analysis is worse than not acting at all, and that there’s a lot that planners can learn from archaeologists about how people actually live and interact with their surroundings.  There are other disciplines that study similar issues in a more rigorous fashion than planners do (it would be hard to do so in a less rigorous fashion), such as sociology, economics, and geography, but in contrast to those approaches, which tend to be limited to the analysis of societies with extensive written records, archaeologists have a much vaster set of data on human settlements over immense time scales.

Plaque at Pueblo Alto Explaining the Chacoan World

And yet, planners don’t bear all the blame for the lack of integration between their ideas and those of archaeologists.  While many archaeologists have studied settlement patterns, land use, and other topics that are of interest to planners, few have synthesized and presented data and interpretations in a way that is accessible to anyone outside of archaeology.  A lot of the most interesting descriptive archaeological research ends up hidden away in the “gray literature” of cultural resource management reports presented to clients who are only paying for the work because it’s required by law and who don’t care about making it available.  Even the research published in more accessible forms tends to be couched in nearly impenetrable jargon, so that seeing connections to issues of concern to professionals in other fields requires considerable experience with archaeology, which those professionals generally don’t have, of course.

One thing I see myself in a good position to do, then, is to help make these connections.  Since I’m familiar with the archaeological literature, situated in a planning school, and in possession of this blog as a mouthpiece, I feel like I can let the planners know what the archaeologists have to say and hopefully eventually try to draw some lessons from archaeology that will be useful for planning.  I’m not at the lesson-drawing point yet, but I think I’m in a good position now to try to relate archaeological data to planning issues.

A useful place to start is with one of the few archaeological articles out there that actually analyzes data relevant to planners’ concerns in a way that makes it easy to show that relevance.  This article was published in 1993 by Bruce Bradley and it reports on work done by Crow Canyon Archaeological Center at Sand Canyon Pueblo in southwestern Colorado.  Crow Canyon is an exception to the tendency I noted above of archaeologists not making their research generally available; they have huge amounts of information about their excavation projects and other work on their website.  In this paper, Bradley analyzes data from excavation in various parts of the site to determine its implications for land use within the Sand Canyon community.  The results are striking.

Head of Little Ruin Canyon, Hovenweep National Monument

Sand Canyon is a classic example of a “canyon-head village” of a type common in the greater Mesa Verde area in the thirteenth century AD.  It seems to have been built, occupied, and abandoned within a quite short period, probably between AD 1230 and 1280, which makes it a useful site for analyzing land use synchronically because there is much less confusion caused by change over time than in communities that were occupied for longer.  The site is built around the head of a canyon with a spring in the center of it.  This spring would presumably have provided domestic water for the community and was probably the reason for the village being built where it was during a period when people throughout the region were aggregating into larger and larger communities, perhaps for defensive purposes.  One of the most striking features of Sand Canyon Pueblo, highly suggestive of defensive concerns, is a large wall that encircles virtually the entire built-up area of the site.  As Bradley discusses, this wall seems to have been built rather quickly using rocks and mud that were easily available nearby.  The type of mud used for mortar in the wall is unlike that used anywhere else at the site for mortar, although it was often used as construction fill, and the masonry of the wall is rough and shows little attention to its appearance, again unlike most other masonry at the site.  The scale of the work effort that would have been necessary to build the wall suggests that it must have been a community effort.

Most of the work described in Bradley’s article was excavation of a few contiguous rooms in each of six of the fourteen roomblocks identified in the site.  Each of the fourteen roomblocks was first given a rough classification based on the apparent ratio of regular rooms to kivas.  Kivas are rooms, usually but not always round, with special features that have sometimes been interpreted as ceremonial but here are defined purely in formal terms without reference to postulated function.  Roomblocks were divided into “standard” (ratio of kivas to rooms near average for the whole site), “room-dominated” (ratio of kivas to rooms lower than average) and “kiva-dominated” (ratio of kivas to rooms higher than average).  Only one block was designated as room-dominated, while six were designated as standard and seven were designated as kiva-dominated.  Interestingly, six of the seven kiva-dominated blocks as well as the one room-dominated block were on the west side of the site, which also had a great kiva and a D-shaped structure similar to the Sun Temple at Mesa Verde, both of which were likely community-scale public facilities of some sort, while four of the six standard blocks were on the east side.  This suggests some sort of spatial differentiation of the formal types of structures, but whether this corresponded to a functional differentiation couldn’t be determined just from surface evidence and required excavation.

Explanatory Plaque at Sun Temple, Mesa Verde

Excavation was done in the one room-dominated block, three kiva-dominated blocks, and two standard blocks.  The sets of rooms excavated were generally selected based on resemblance to the classic “unit-type pueblo” that is a common form for earlier sites throughout the region.  These sites typically consist of one or two kivas and a few associated square rooms.  In the context of Sand Canyon, excavation units consisted of sets of rooms suspected to comprise “kiva suites” consisting of a single kiva and all rooms associated with this kiva.  Bradley is careful to note that this “kiva suite” concept “may or may not be equivalent to” the unit-type pueblo, but there is clearly some similarity and the underlying idea is that a large aggregated site like Sand Canyon may be made up of a bunch of unit-type pueblos “stuck together.”  Since each excavation unit consisted of a kiva and some square rooms, they were not all necessarily typical of the room blocks in which they were located, which may have been kiva-dominated or room-dominated as well as standard, which is the type that most closely matches the kiva suite ratio.

The results of the excavations basically bore out the pattern suggested by the distribution of roomblock types.  Three of the excavated kiva suites were clearly residential (and therefore roughly equivalent to unit-type pueblos).  Two of these were on the east side of the site in standard blocks, and the third was in a kiva-dominated block on the west side.  The excavated rooms in the room-dominated block on the west side turned out to not be a full kiva suite, so little could be concluded about their function.  The two remaining sets of rooms were in kiva-dominated blocks on the west side and seemed to be non-residential, although their precise function was unclear.  One of these actually consisted of three adjacent kivas with few associated rooms, which Bradley interpreted as three separate “kiva suites.”

Far View Tower, Mesa Verde

The construction histories of the excavated units were also noteworthy.  The ones in close proximity to the site-enclosing wall were all clearly constructed after the wall was already there, and in some cases other structures such as towers were also present before construction of the kiva suites began.  Each of the suites seems to have been constructed gradually, generally with the kiva and a few rooms being built first and additional rooms being added on as needed, rather than at once as a unit in accordance with a preconceived plan.  The level of construction effort involved in each suite was such that they were probably constructed by individual families and expanded as needed by changes in family demographics.

While the individual residential suites, and perhaps the special-function as well, seem to have been built on a small scale and not particularly planned, the same is not necessarily true of the site as a whole.  Here’s what Bradley says:

Although growth by accretion is indicated within individual kiva suites, and probably within architectural blocks, there is evidence that the overall layout of the site was planned.  The construction of the site-enclosing wall, in relation to cliffs and ledges, preconditioned the spatial organization of the individual architectural blocks to some extent.  Furthermore, the spacing of the architectural blocks in relation to each other, the central plaza, the D-shaped multi-wall structure, and the great kiva may indicate that there were planned zones of construction, and that they may have been dedicated to specific uses and functions.  If this is an accurate assessment, the east side of the site functioned primarily as a habitation area, while the west side was more specialized in function.  This is seen in the spatial relationships of kiva-dominated blocks with public architecture and in the apparent lack of these relationships between most of the standard architectural blocks and public spaces.  This is evidence of overall planning at the site level in which the location of architectural blocks was anticipated and the allocation of habitation, specialized function, and public areas was predetermined.  Rather than total site planning at the architectural unit level, this pattern most closely resembles functional zoning.

I trust the relevance of this to modern planning is obvious.  Local government action to zone specific areas of a city for specified uses, with actual construction left up to individual landowners except in the case of public buildings, is how the planning system has worked in the US since the 1920s.  Obviously there’s no direct connection between this and whatever was going on at Sand Canyon in the 1200s, but the parallel is fascinating and definitely worthy of further study.  Why did the people at Sand Canyon apparently seek to organize their land uses this way?  Was it a longstanding tradition that just hasn’t been recognized before because no one has looked for it?  Was it an innovation by the people of this specific community, or by a larger cultural group in the area?  Did this pattern continue once southwestern Colorado and surrounding areas were abandoned around 1300 and their inhabitants moved elsewhere?  Bradley notes that more research seeking to determine how widespread this type of zoning was and how long it was used would be very helpful in understanding it here.  Unfortunately, as far as I know no one has followed through on this by conducting similar studies at other prehistoric communities, although there may be some work along these lines with which I am unfamiliar.

Bradley suggests that this type of intracommunity functional separation, if not a longstanding pattern in the Southwest, may be associated with the Chacoan communities of a slightly earlier period.  There is evidence for the survival of some Chacoan cultural and architectural forms in some areas long after the decline of the Chaco system proper, including in the Mesa Verde region, so it’s possible that this land use system was a Chacoan innovation.  More research will be necessary to tell.

Sand Canyon Inn, Cortez, Colorado

Archaeologists often talk about land use in prehistoric societies, but they rarely present arguments like this with such obvious correspondences to modern concepts and practices.  I doubt this is because such arguments could not be made.  I think it’s more likely that archaeologists simply aren’t accustomed to thinking of the societies that they study as comparable to the society they personally inhabit in meaningful ways, so they don’t think to try to make such comparisons.  This is a particularly straightforward case, of course, and not all studies of prehistoric land use and other issues will necessarily show such striking parallels to the concerns of modern planners, but it’s worth thinking about the possibility of such parallels when interpreting archaeological data.  Until the archaeologists are ready to do this themselves, however, I’m happy to do it for them.
ResearchBlogging.org
Bradley, B. (1993). Planning, Growth, and Functional Differentiation at a Prehistoric Pueblo: A Case Study from SW Colorado Journal of Field Archaeology, 20 (1) DOI: 10.2307/530352

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Two Years

Beginning of Lunar Eclipse on Winter Solstice 2010 from Highland Park, New Jersey

Today is the winter solstice, which means it’s now been two years since I started this blog.  In the past year my readership has increased quite a bit, which has been quite gratifying.  This has always been something of a niche blog, so I don’t expect it to ever get huge numbers of readers, but it’s been quite nice to see how it’s developed.  When I started it one of my main purposes was to find a place to permanently put versions of my well-rehearsed answers to the questions I would frequently get as a tour guide at Chaco, and I’ve mostly accomplished that goal at this point and moved on to other things.  Right now, since I’m in school and have access to a major university library system and a lot of scholarly databases, one of my main purposes is to present and explain important and interesting pieces of scholarship that the general public does not generally have easy access to.  That may change in the future as my personal circumstances and intellectual interests change, but I don’t see this blog going away any time soon.  Thanks to all my readers for making this a fantastic two years so far.

Oh, and the eclipse last night was quite impressive.  Here in New Jersey the sky was clear and we could see it very well.  I hear it was overcast in much of the Southwest so a lot of people couldn’t see it, which is unfortunate.  I took some pictures.

Total Lunar Eclipse on Winter Solstice 2010 from Highland Park, New Jersey

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Solstice Eclipse

Winter Solstice Sunset

Astronomical events are closely associated with Chaco Canyon, and the summer and winter solstices seem to have been particularly important to the ancient inhabitants.  The winter solstice is coming up tomorrow, and there also happens to be a total lunar eclipse that will coincide with it.  It’s very rare for an eclipse to occur right on the solstice, so I figured I’d put out the word for any of my readers who haven’t heard and might be interested in watching it tonight.  It’ll be visible throughout North America, provided the sky is clear, starting at about 1:30 am Eastern Time.  At particularly dark locations like Chaco the eclipse will be more spectacular, of course, but the thing about eclipses is that they’re visible even in more developed areas with more light pollution, so a lot of people should be able to see this one.

Sun Temple, Mesa Verde

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Sunset Crater Volcano

The effect of the eruption of Sunset Crater Volcano on the prehistoric population of northern Arizona has long been a topic of interest to archaeologists.  As I’ve mentioned recently, in the 1930s and 1940s Harold Colton of the Museum of Northern Arizona in Flagstaff came up with a theory to explain the settlement dynamics of the Wupatki area northeast of Sunset Crater.  In Colton’s view, the eruption resulted in a level of volcanic ash falling on Wupatki that acted as a mulch to retain water and make that very arid area suitable for farming for the first time, resulting in a “land rush” in which people from all over the region converged on Wupatki to farm the newly available land.  Over time, however, the ash began to blow away and the land became less productive, so people aggregated into the large pueblos for which Wupatki is best known, then left entirely when the area could no longer support its population.  Dendrochronological evidence from timbers at Wupatki Pueblo later provided a basis for dating the eruption to around AD 1064, which would put the “land rush” shortly after that.  Other evidence has shown that the abandonment of the area probably occurred some time in the thirteenth century, a time when many parts of the Southwest were being abandoned as well.

As I’ve mentioned, recent archaeological survey at Wupatki has cast doubt on some aspects of this model.  The main influx of population seems to have come after AD 1130, a few decades after the eruption, and the scale of that influx was probably quite a bit lower than Colton estimated, since many of the sites he counted to compute his population estimates were probably season field houses or other temporary structures rather than permanent habitations.  This implies that there wasn’t really a “land rush” the way Colton described it, but rather a substantial increase in population at some point after the eruption, perhaps in response to drought or other problematic conditions in other parts of the Southwest.

A few parts of Colton’s model do seem to hold up, however.  Experiments have shown that the levels of ash found at Wupatki do indeed work well as a mulch.  Without this mulch, dry farming in the area with any reasonable measure of reliability is basically impossible, since there just isn’t enough rain, and irrigation or floodwater farming isn’t possible on any substantial scale either due to the geological conditions and the lack of permanent surface water sources.  Furthermore, the Wupatki survey showed that this lack of agricultural suitability made the area essentially uninhabited before the eruption.  Of nearly a thousand datable sites recorded by the survey, only two dated to before the eruption.  The biggest influx of population came after about 1130, but there was already a fairly significant movement of people into the area in the immediate post-eruptive period.  Perhaps these people first experimented with agriculture using the ash as a mulch, and were so successful that when conditions deteriorated elsewhere others joined them.  The ash was liable to blow away in the strong winds, however, and over time the advantages it offered as a mulch would have diminished as a result of this and other factors, so it’s quite possible that it was declining agricultural productivity, perhaps exacerbated by warfare to defend land claims, that led the area to be abandoned in the thirteenth century.

Volcanic Rock in Masonry at the Citadel, Wupatki National Monument

That’s all well and good, but where did the people who moved to Wupatki after the eruption come from?  Colton saw them as coming from all over, but at least in the immediate post-eruptive period a more specific answer is tempting: perhaps they came from the area right around the volcano, which would have been rendered uninhabitable (and certainly unfarmable) by lava flows and massive ash fall.  A relatively recent paper takes a close look at the circumstances of the Sunset Crater eruption and its likely effects on local people, and basically comes to this conclusion.

From a detailed analysis of the details of the eruption, the authors of this paper found that the area of the heaviest ash fall and the largest lava flows was probably densely populated and heavily farmed before the eruption.  They cast some doubt on the tree-ring evidence pointing to an AD 1064 date for the eruption itself, but they argue on other grounds that the eruption likely took place between AD 1050 and 1100 and that it was relatively quick, lasting from a few weeks to a few years at the most.  Because the high-elevation area where the eruption took place gets more precipitation than lower-elevation Wupatki, it would have been the most favorable area for farming at the time, and a large number of homes and farms were likely buried by the lava and ash.  The amounts of ash falling right around the volcano would have been much too thick to serve as a mulch.  The ash itself is sterile, so it could only function effectively as a mulch if plants could reach their roots down through it to the soil underneath.  The few inches of ash cover at Wupatki would have allowed this, but the uplands immediately around the volcano got over a foot of ash, which would have effectively killed any agricultural potential.

Lava at Sunset Crater

Thus, the effects of Sunset Crater on local agriculturalists were two-fold: they were forced to leave a rather large and previously quite productive agricultural area around the volcano, but they were able to go to a previously unproductive area nearby that was made newly fertile by the ash.  Cinder-cone eruptions like the one that created Sunset Crater rarely cause much direct loss of life, and that would have been particularly the case in this context, since the pre-eruption populations lived in dispersed farmsteads and were probably not organized sociopolitically at any level above the household or extended family.  This would have allowed rapid reactions to the eruption, which would primarily have taken the form of migration away from the immediate area.  Since the population was so dispersed, people fleeing the ash-fall zone would likely have had relatives or friends in less affected areas to whom they could go for shelter and assistance in the immediate aftermath of the eruption.  The population movements spurred by the eruption, however, could well have resulted in groups infringing on territory claimed by others and resulting violence and loss of life.  Within this context, the relatively empty Wupatki area may have seemed particularly attractive even before its enhanced potential for farming was discovered.

Another reaction of people in the local area to the eruption, which was documented in an earlier paper by some of the same authors, was the apparent practice of placing corncobs in the path of lava and carrying the resulting “corn rocks,” with visible imprints of the cobs (which were vaporized by the heat) to rather distant settlements.  Given the amount of effort this would have required, it probably had some ritual significance, perhaps to appease the spirits of the volcano or something similar.

Mt. Trumbull from Pipe Spring National Monument

In addition to the Sunset Crater eruption, the authors of this paper also discussed a smaller and less studied eruption that likely took place about the same time at Little Springs, next to Mount Trumbull on the Arizona Strip just north of the Grand Canyon.  Here there was relatively little ash fall, so the loss of productive land and enhanced productivity of other land seen in the Sunset Crater case did not occur.  Instead, the main effect was a lava flow, with the land immediately surrounding it continuing to be largely ash-free and fertile.  The people who had lived and farmed in the immediate area covered by the lava flow would have had to leave, but people clearly continued to live and farm right around the lava, and they also built sites on top of the flow itself.  These sites have few artifacts and likely served defensive purposes, a theory that is supported by the presence of an elaborate system of trails on the lava flow that would have made it an effective refuge in times of war.  The use of defensive refuges or strongholds separate from ordinary living quarters is well-attested in the prehistoric and historic record of the Southwest.  Similar to the corn rocks at Sunset Crater, in this area there were some rocks with potsherds embedded in them, a sign of similar ritual behaviors with respect to the volcano.

These two eruptions and the different reactions to them by local populations show the effects that sudden, catastrophic events can have on human societies.  The eruption of the much larger White River Volcano a bit earlier and its effect on local Athapaskan populations in Alaska and the Yukon is another example.  Unlike many other catastrophes, volcanic eruptions are generally pretty visible in the archaeological record, which makes them a useful source of information on how societies adapt to sudden shocks.
ResearchBlogging.org
ORT, M., ELSON, M., ANDERSON, K., DUFFIELD, W., & SAMPLES, T. (2008). Variable effects of cinder-cone eruptions on prehistoric agrarian human populations in the American southwest Journal of Volcanology and Geothermal Research, 176 (3), 363-376 DOI: 10.1016/j.jvolgeores.2008.01.031

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