The Blick Mead tooth conundrum
I wrote a long blog about Stonehenge the other day, featuring the road tunnel and a dog tooth from Blick Mead. David Jacques commented on the latter, and gave a link to the Buckingham University press release on the story. It confirms that Peter Rowley-Conwy, of Durham University, said “the dog would have been roughly the size, shape and possible colour of an alsatian.”
Most usefully, it has a link to Durham University’s website, with a response to the press coverage. This includes a further link to a very helpful poster about the isotope study: “Stable isotope analysis of the Blick Mead dog: a proxy for the dietary reconstruction of mesolithic hunter-gatherers,” by B Rogers, DR Gröcke, K Gron, J Montgomery, P Rowley-Conwy and D Jacques.
A single domestic dog tooth, they say, was found at Blick Mead “in a context which produced faunal remains which have been radiocarbon dated to 4989–4808 cal BC”. I’m not clear where that (over-precise) date comes from – it doesn’t match any published determinations – but it sits in the region where most of the site’s dates lie, between about 7,500 and 6,250 years ago. This is the only dog remain yet found at Blick Mead.
As the title says, the poster is mainly about diet. The idea is that domestic dogs eat similar food to the people they hang out with, so the dog’s diet should give an idea of what the folk at Blick Mead were eating. The tooth dentine was incrementally sampled, so as to compare parts of the tooth that grew at different times. Carbon and nitrogen stable isotopes were similar at all points, suggesting no great change in diet during the dog’s life. Values for both are described as being significantly lower than those for mesolithic dogs at the Yorkshire sites of Star Carr and Seamer Carr. They interpret the figures for the Blick Mead dog as indicating that it ate meat, and gnawed bones or ate freshwater fish, and possibly less marine food than the Yorkshire dogs – summarised as “terrestrial mammals with a possible inclusion of freshwater fish”.
The result of oxygen isotope analysis is also described. The enamel produced a “drinking water value” of -8.1 per mill. Compared to such values for modern Britain, this is too low for the south-west. A warmer climate in mesolithic Britain, say the authors, would have caused a higher value, not a lower one, so on the face of it, it seems safe to say that this dog grew some way north of Blick Mead – in fact, judging by the map they feature (see below), from a limited area of Yorkshire and the East Midlands, or from eastern Scotland. The tooth is a permanent premolar, which, they say, forms after weaning is finished.
So perhaps the Vale of York doesn’t sound so bad after all as a home for the Blick Mead puppy. There is, however, a proviso. Aurochs teeth (not otherwise mentioned in the poster) “produced even lower” oxgen-18 values: so low, they are “largely incompatible with modern Britain”. Does this mean the aurochs at Blick Mead grew up outside Britain altogether? Bearing in mind that by the time hunter-gatherers were camping out at Blick Mead the English Channel had long been breached, this seems unlikely, to say the least.
So how do we explain the “incompatible” low oxygen values? The answer, they suggest, may lie in the fact that the necessary equations “were developed using human remains rather than aurochs or dog remains, which may fractionate water differently possibly making oxygen-18 values appear lower than expected.” Body size could also be a factor, they say.
This is really interesting work. However, it seems clear that more research is needed before we can conclude anything firmly from the oxygen isotope data alone. On the available evidence, we certainly can’t say with any confidence exactly where the dog grew up. Bryony Rogers had previously told me they are progressing with strontium isotope analysis. We await those results with further interest.