This paper employs δ 13 C and δ 15 N analysis of bone collagen to explore animal management at large Norse settlement sites in the liminal environments of the Scottish North Atlantic Islands. The Norse period was a time of social, cultural and economic change; the need to feed an expanding population and the demand for trade meant that domestic stock were a crucial resource. Our results indicate that rearing animals in these challenging insular environments required careful management. At all sites, the diet and movement of domestic cattle and sheep were highly similar and carefully controlled and, despite many of the analysed settlements lying close to the coast, there was no use of shorefront grazing or fodder resources. In contrast, pig rearing strategies varied across the island groups. In the Western Isles pig diets were diverse, indicative of household or ad hoc management, whilst on Orkney all pigs consumed a more restricted diet based primarily on terrestrial protein. A comparison of red deer with domestic stock on the Western Isles indicates that both groups were exploiting similar grazing niches.