New isotope analysis of a jawbone found buried against the outside wall of an Iron Age broch at The Cairns on South Ronaldsay, Orkney, has shown that seafood was probably a major part of this person’s diet throughout their lifetime – an unusual discovery as, during this period, marine resources appear to have been rarely consumed.
The mandible was first discovered in 2016 during an excavation by the UHI Archaeology Institute, led by Martin Carruthers. Dated to c.AD 120-240 – around the same time that the broch was probably decommissioned – the bone appears to have been placed inside a large vessel made from a whale vertebra and carefully surrounded by the remains of three newborn lambs, two red-deer antlers, and a saddle quern (ABOVE). Interestingly, this whale bone belonged to a fin whale, the remains of which – based on aDNA analysis – have been found in several different deposits around The Cairns (see CA 363).
Previous isotope analysis of the bone had shown that this person – recently identified as female through aDNA analysis – had a marine-based diet during the last years of her life (see CA 323). Researchers initially assumed that this may have been due to the fact that she had few teeth remaining – suggestive of advanced age, and the reason why she has been nicknamed the ‘Elder’ (BELOW) – and so she may have consumed seafood as it was easier for her to eat. This most recent analysis, however – carried out by the University of York as part of the COMMIOS research project in partnership with the National Environmental Isotope Facility – used her first molar, which provided information about her diet during childhood. This revealed that she had been eating seafood throughout the time this tooth was forming, from the ages of 3 to 15. Combined, the isotope evidence seems to suggest that marine proteins were a staple of her diet over her entire lifetime.
Other people buried at The Cairns do not appear to have consumed seafood in any quantity, however, so the question remains as to why this woman was different. Strontium and oxygen isotopes suggest that she was local to Orkney, so this is not a case of a migration into the community. Was she special in some other way? Could this be why she was singled out for such an unusual type of burial?
The broch against which she was buried may provide some clues. The ground-floor rooms appear to have been divided into two separate halves. Finds from the north-west side mainly represent meat preparation. Around a main hearth lots of fragments of bone – both burnt and unburnt – have been found and, in particular, many were bones from the lower legs of red deer, which appear to have been split in order to extract the marrow. In contrast, on the south-east side of the broch a number of stone and bone tools have been recovered, as well as the remains of marine life – so it does appear that the Iron Age people of The Cairns were at least catching fish, even if the majority of them were not eating them. Could this, then, have been a resource reserved for specific people, including the ‘Elder’? Research at the site is ongoing and it is hoped that more details may help answer some of these questions.