Focus on finds – the Orkney vole
Among the animal remains found at the Ness over the years are hundreds of bones from the Orkney vole (Microtus arvalis orcadensis).
This small mammal is not found in mainland Britain – only Orkney and the European Continent. Genetic analysis and radiocarbon dates suggests the vole arrived in the islands between 3455–3100BC , possibly as a result of long-distance sea travel between Orkney and Europe. 
Suggestions as to the origin of the Orkney vole have varied over time, with suggestions being France, Spain and Belgium.
Their point of original and whether their introduction was deliberate or unintentional remains a topic of debate.
With Belgium as the proposed prehistoric departure point came the suggestion that the introduction of voles to Orkney was either accidental, carried in the “plentiful grass livestock bedding/fodder in which the vole stowaways could have survived”, or deliberate, brought as “food items, pets or for cultural/religious purposes”. 
Dismissing the Belgian connection, Sheridan and Petrequin instead suggest that “it is not beyond the bounds of possibility that a sea journey between Brittany or Iberia and Orkney had occurred.”
“The deliberate transportation of voles as a source of food would, in the circumstances, be a sensible strategy, comparable to that used by Roman seafarers using edible dormice, and perhaps also Polynesians in the case of Pacific rats…” 
“The evidence […] indicates that the accumulation and burning of Orkney vole remains were most likely the result of deliberate actions by the inhabitants of the settlement, carried out over a considerable period of time, and the most plausible explanation is the utilization of the voles as a source of food.” 
-  Bayliss, A., Marshall, P., Richards, C. and Whittle, A. (2017) Islands of history: the Late Neolithic timescape of Orkney. Antiquity, 91(359), 1171-1188.
-  Thaw, Susan; Jaarola, Maarit; Searle, Jeremy B.; Dobney, Keith M. (2001) Lost in Space: the origin of the Orkney vole Microtus arvalis orcadensis and its potential for reconstructing human dispersal and trade and exchange networks in the Neolithic. Orkney Archaeological Trust.
-  Martínovká, N., Barnett, R., Cucchi, T., Struchen, R., Pascal, M., Pascal, M., Fischer, M.C., Higham, T., Brace, S., Ho, S.Y.W., Quéré, J.P., O’Higgins, P., Excoffier, L., Heckel, G., Hoelzel, A.R., Dobney, K.M. and Searle, J.B. (2013) Divergent evolutionary processes associated with colonization of offshore islands. Molecular Ecology 22, 5205–20.
-  Sheridan, J.A. and Pétrequin, P. (2014) Constructing a narrative for the Neolithic of Britain and Ireland: the use of ‘hard science’ and archaeological reasoning. In Whittle, A.W.R. and Bickle, P. (eds) Early Farmers: The View from Archaeology and Science, 369–390. Proceedings of the British Academy 198. Oxford, Oxford University Press/the British Academy.
-  Romaniuk, A.A., Shepherd A.N., Clarke D.V., Sheridan A.J., Fraser S., Bartosiewicz L., Herman J.S. (2016) Rodents: food or pests in Neolithic Orkney. R. Soc. open sci. 3: 160514. http://dx.doi.org/10.1098/rsos.160514
- The mystery of the Orkney vole. Julian Branscombe and Keith Dobney. (2016)
- Cucchi, T., Barnett, R., Martínková, N., Renaud, S., Renvoisé, E., Evin, A., Sheridan, A., Mainland, I., Wickham‐Jones, C., Tougard, C. and Quéré, J.P., (2014). The changing pace of insular life: 5000 years of microevolution in the Orkney vole (Microtus arvalis orcadensis). Evolution, 68(10), pp.2804-2820.
- Orkney vole at risk of extinction.