Monday, 23 June 2014

Ethnoarchaeology - animal dung in Iraqi Kurdistan

I've just been notified of the publication of this great new paper via Google Scholar citations, as it cites my paper on lipid analysis of coprolites. That's not the only reason I'm writing about it mind you - anything dung related gets my attention, and this is one of the first papers to come out of the Central Zagros Archaeological Project, which I was involved with a number of years ago. The CZAP project aims to understand the origin and process of animal domestication and agriculture in the Central Zagros region of Iran and Iraq, and the team have also conducted ethnographic studies in modern villages in the area, in order to help interpret the archaeology. This paper by Elliot et al reports on a mix of ethnographic studies and scientific analysis of modern dung and plants.
The authors look at the dung spherulites in modern samples of sheep, goat and cows - those little spherical particles that form in the guts of animals. Despite being used frequently to support the identification of animal dung in archaeology, we still know very little about how and why these particles are produced. This paper provides some interesting data. There appears to be a variation in sperhulite production between species, with adult sheep/goat producing more than cows. However immature sheep also produce smaller amounts.  Perhaps it is related to grazing patterns? They also noted that the phytolith content from sheep/goat are richer in leaves of shrubs and trees compared to cows. Combined with the lower content in immature sheep (presumably still milk feeding), this could indicate that the diet and perhaps intake of minerals leads to an increased production of spherulites.

The authors also show that the strontium isotope signal of modern plant material varies between the alluvial floodplain and the lower foothills. It will be interesting to see further work which compares these lines of evidence - phytoliths, spherulites and isotopes - to see whether there is a link for example between the grazing locations and habits of sheep and goat compared to cow. I like the approach to this study, as it considers agriculture and animal management from a whole landscape perspective, i.e. the team are bringing together a wide range of evidence from the landscape to help understand early farming. Interdisciplinary work produces the most robust interpretations of fragmentary archaeological evidence!

Elliot et al. 2014. Figure 4 Sheep and goats daily grazing in fallow fields, on the alluvial flood plain Bestansur, Iraqi Kurdistan, summer 2012.

Environmental Archaeology

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