The antiquity of the practice of grazing on and/or foddering with seaweed is of interest in terms of understanding animal management practices in northwest Europe, where provision had to be made for overwintering. Orkney holds a special place in this discussion, since the sheep of North Ronaldsay have been confined to the seashores since the early nineteenth century, and are entirely adapted to a diet consisting mainly of seaweeds. Here, we report the results of stable carbon and nitrogen isotope analysis of twenty-five faunal specimens from the Neolithic chambered tomb of Quanterness, Orkney. Three of the 12 sheep analysed show elevated δ13C values that can only be explained by the consumption of seaweed. Radiocarbon dates place two of the three animals in the Neolithic, coeval with the use of the monument for burial, while the third animal dates to the Chalcolithic/Early Bronze Age. The findings are placed into the wider context of previous isotopic analyses of domestic fauna from prehistoric Orkney. A possible disjoint is noted between the results for bone collagen – where seaweed consumption seems to relate to the pre-natal period, since all the animals with high δ13C values are less than ca. three months of age – and previous studies using high-resolution sequential enamel measurements, which suggest a repeated pattern of winter consumption of seaweed in older animals.
Bibliographical noteMany thanks to Alison Sheridan and the National Museums Scotland for permission to sample the Quanterness fauna and to Richard Sabin of the Natural History Museum, London, for facilitating access to the collection, which was in temporary storage there. Thanks also to Marie Balasse and an anonymous referee for their very useful feedback, and to Marie Balasse for permission to cite her doctoral thesis and to reproduce a graph of her stable isotope results. The wonderful photograph of a seaweed-eating sheep from North Ronaldway in the graphical abstract is courtesy of the Orkney Sheep Foundation. The research was supported by the Research Laboratory for Archaeology and the History of Art, University of Oxford, and by the 14CHRONO laboratory, Queen's University Belfast. The authors did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
- stable carbon isotopes
- quanterness chambered tomb
- palaeodietary modelling
- marine reservoir effect