No Pig Atoll: Island Biogeography and the Extirpation of a Polynesian Domesticate

Abstract

The significance of the domestic pig, Sus scrofa, to prehistoric Polynesians is hinted at by its inclusion among the species that they transported with them as they colonized Oceania. However, archaeological data reveal a pattern of pig distribution far more extensive in prehistory than at historic contact. Domestic mammal extirpation is a phenomenon apparently unique to prehistoric Polynesia. Although well recognized, the local extinction of domestic pigs in Polynesia prior to European contact has yet to be satisfactorily explained. Earlier accounts attributed the patchy distribution of pigs across the Island South Pacific to intentional extermination by their Polynesian keepers. More recent approaches seek to understand the disappearance of these animals within a biogeographic and ecological framework. Here, I test the hypothesis that the success of pig husbandry is correlated with ecological variables and demonstrate that the likelihood of pig extinction increases with decreasing island size.

Dynamics of Polynesian Subsistence: Insights from Archaeofauna and Stable Isotope Studies, Aitutaki, Southern Cook Islands

“…We cannot, however, discount the possibility that the reduced variability in pig diets is an artifact of the small size of the late sample, with only three observations, compared with the two earlier periods, where there are eight (I) and seven samples (II). Nevertheless, by European contact, reputedly both dog and pig had been extirpated (Williams 1837, Bligh 1937, a pattern that has been found on several other small Polynesian islands (BayPeterson 1984, Kirch 2000, Giovas 2006 and one that is often associated with interspecific competition (Oosting 1956, Begon et al 1996. discussion The combined archaeofaunal and stable isotope records provide a detailed view of subsistence change on Aitutaki, one that speaks to both plant and animal food sources and is relevant not only to human but also to domesticate animal populations.…”

“…In contrast to the relatively uniform boom-bust experiences of early island colonists, change in the postcolonization period was more subtle, complex, and geographically varied. Different combinations of domesticates were emphasized, depending on local conditions, and in some cases (notably small islands) animal competitors were extirpated (Bay-Peterson 1984, Kirch 2000, Giovas 2006. Although marine foods were widely utilized, preferred habitats and species changed over time, in response to human impacts, environmental perturbations, and cultural dictates (e.g., Spennemann 1987, Leach et al 1999, Allen 2002, Barber 2003, Masse et al 2006, Morrison and Cochrane 2008.…”

New Perspectives in Southeast Asian and Pacific Prehistory

“…Domestic animals are also continuously represented throughout the archaeological sequences. Giovas (2006) has noted that there is high probability of pig extinctions on islands, at least in Polynesia, if island size is less than 11.64 km 2 . This is possibly due to the perceived unsustainability of maintaining pig populations on resource-impoverished islands over the long term, and pig populations were either allowed to die out or deliberately exterminated.…”

DNA and Pacific Commensal Models: Applications, Construction, Limitations, and Future Prospects

“…Once introduced, populations must be maintained, which may mean providing protection from predators including other domesticates such as pigs and dogs. In the case of introduced animals, populations may also require feeding and thus impact upon the overall food surplus (Bay-Petersen 1984;Giovas 2006;Kirch 2000b). Finally, should an island's population of animals or plants become endangered or extinct, people can later choose to use their established trade networks to reintroduce species or merely to trade to meet their immediate needs for end products.…”