Since at least the nineteenth century, islands have held a privileged position in evolutionary and ecological thought. Encircled by water, the self-containment of an island offers a a discrete unit—an evident “natural laboratory” where the selective forces of evolution operate with more intensity, and therefore more apparently to the human observer. An insular laboratory, though, is as much the outcome of literal and figurative work as its brick and mortar counterpart, as a close look at the archipelago of St Kilda in the North Atlantic reveals.
Home to an unusual type of sheep called Soays, and believed to be the oldest known breed of domesticated sheep in Europe, ecologically-minded visitors to St Kilda since the 1950s have found there a natural laboratory par excellence—a simplified ecosystem that reveals the dynamic relationship between an herbivore population and its food source in the absence of predation, competition, or human interference. The insights that intense longitudinal study of these sheep reveal, however, are dependent upon the erasure of a much longer history of St Kilda, which includes (among other things) a long history of human occupation that came to a close only in 1930. Attention to this deeper and more complex past, as well as to the interpretive decisions made by the scientist who study Soay sheep, force us to reconsider the notion of a “natural laboratory,” as well as the historical and scientific explanatory power of islands more generally.