A Clarification

The last time we spoke, we were discussing the mysterious trenches surrounding at least four (possibly 5) of the ancient Upper Xingu (UX) settlements. We considered several hypotheses to explain the reason behind their construction, ranging from attempts to thwart ravenous peccaries to advances in irrigation. Finally, however, we settled on accepting that the trenches served as defensive structures, especially since the sites at which the ditches are present have yielded archaeological evidence (complex road structures, elaborate central plazas) to suggest that these occupations were major residential centers. Gotta protect the goods, right?

Then we looked at a picture of one of the trenches at X6: Nokugu.
This picture, actually:

I led you in marveling at its dimensions--3 ft. by 17 ft., as recorded by Heckenberger. And I'm still taken aback at how deep that is. It truly must have required a substantial amount of labor, and what a terrible fate awaited any ne'er-do-well that should happen across it. Such a defensive trench seems pretty efficient, and pretty tidy!

But then, a thought occurred to me.

The dimensions.

Yes, 17 ft., that's quite a depth, and if someone fell (or was pushed?!) into that, the result would not be pretty.

But 3 ft.? What good would having a 3 ft.-wide ring around an important settlement do? 

In my mind, I envisioned what a hostile attack on X6: Nokugu might have looked like from this perspective:

Enemy approaches!
Clearly very hostile.

"But what's this? A treacherously deep defensive ditch?
Does this mean I won't be able to attack the village on the other side?"

"...Nope."

(Running start)

"HAHAHAHAAA!"

"Ready or not, here I come!"

If the defensive ditch is only 3 ft. wide, I'm pretty sure that any enemy willing to go through the effort of attacking a populous village would have no trouble jumping over it.

So, understandably, I was a little confused--this doesn't exactly make for the strongest "defensive structure" argument. I needed some answers!

The first thing I did was reread the caption of the Heckenberger's trench photo, incredulously.

"Fig. 3.8 Excavation of trench one (1993; top) and trench 10 (2002), both bisecting ditch two at Nokugu. Note trench 10 was 5.2 meters deep from the base of the narrow funnel-shaped basal portion (about 1 meter wide), a possible seat for palisade trunks, to the top of the inside berm" (85).

And therein lay the problem. Well, problems. In my excitement at actually having a picture of the infamous trenches, I didn't read the caption very carefully. While these pictures are, in fact, structures found at X6: Nokugu, they're not the peripheral ditches that primarily concern us. So what the heck are they, then?

Let's take a look at the X6: Nokugu GPS plan, shall we? (p.82):

Now, I originally thought Heckenberger was referring to the middle arc. But actually, the pictures he provides are of two "trenches" that cross the arc at one of these 3 points:

 So, fail on my part. (I just assumed that people would take and share photographs of the most interesting discoveries. I guess not.) 

However, another difficulty arises in that, according to Heckenberger's caption, he unofficially makes a distinction between the terms "trench" and "ditch," whereby only "ditch" refers to the earthworks interpreted as defensive structures ("trench" apparently refers to another hole in the ground of debatable purpose). This is a risky move on his part that should not be made so subtly--much of the literature I have come across have used these two interchangeably, and many scholars, such as Dr. Carneiro, have preferred to use "trench" when speaking of the defensive structures. (And anyway, if I had to pick one, I would be inclined to select "trench" myself--I mean, as far as connotations go, "ditch" doesn't have a very strong one. It's like, "Oh, yeah, I tripped and fell in a ditch." Or, "Come on, Johnny, let's go dig a ditch." As opposed to "Oh, yeah, I fell in a TRENCH." Or, "Come on, let's go dig a TRENCH!" You don't exactly get the same mental image with both of those words, do you? For the sake of this blog, I will align myself with the others in the anthropology/archaeology community that use "ditch" and "trench" interchangeably. If I use one of these terms and I'm NOT referring to the defensive structures, I'll say so.
As far as I'm concerned, two very important lessons can be taken from this experience.

#1. Read captions carefully.
#2. Do not assume readers will interpret the connotations of technical terms in the same manner in which one has used them.

I'll definitely remember these, especially when it comes time to organize our research into a public paper.

Yet even after I identified my misunderstanding, I was still concerned--what WERE the dimensions of the other ditches, then? As far as I could tell, Heckenberger never really gave a definite account of the precise physical dimensions of the ditches (though I will admit, I am less inclined to trust my initial impressions now, after that caption fiasco! But I did revisit the site descriptions in search of measurements, but to no avail.)

Well, what were the trenches like? How in the world would I be able to get an answer that question? The mysterious trenches of the UX aren't exactly high up on the "Most Visited Destinations" list. Where in the world would I be able to find someone else who had seen these structures? Dr. Carneiro, of course! After all, he was one of the first anthropologists to study in the UX. So the next day I explained my confusion, and tenuously took him through my mental image of the jumping invader, very much afraid that the entire "defensive structure" theory would be unraveled at any moment. But Dr. Carneiro put my fears to rest:

Though he did not have extensive exposure to the X6: Nokugu peripheral ditches, he was very familiar with those at X11: Kuhikugu to the south. As Heckenberger describes X11: Kuhikugu, back in its day this was the largest residential site (79), so we can be sure that there were things worth protecting at this location.

For reference, here is the site plan:

Now, Dr. Carneiro himself has stood alongside the external trench (the one that I've faintly highlighted in yellow), and while he never conducted any formal measurements of the structures, he estimated that the ditch ran approximately 8-9 ft. deep, and spanned a width of about the same. That's roughly half the depth of Heckenberger's X6: Nokugu "trenches," but the width makes the X11: Kuhikugu ditches 100x more formidable.

"Defensive structures," it would appear, 

is still on the table as a probable explanation. 

Hooray!

Now that I've made that clarification, I promise we'll continue with our investigation!

Up next: Who posed such a threat to the Arawaks (remember, in the last post we discussed that the implications of Heckenberger's soil dating results put the settlement of X6: Nokugu, for one, at c. 900 a.d., meaning the Arawaks were the ones who erected these occupations) that they would undertake the construction of such defensive structures?

 (I also just want to point out that I went back and reread the above caption for the X11: Kuhikugu plan extra-closely after I realized my faux-pas with the X6: Nokugu situation, and Heckenberger himself uses the term "trench" to describe these same structures that he also refers to as "peripheral ditches" in other instances.)