Mammal extinction by introduced infectious disease on Christmas Island (Indian Ocean): the historical context

Two endemic rat species, Rattus macleari and R. nativitatis, went extinct on Christmas Island more than a century ago, contributing to an unenviable record of mammal extinctions in Australia. This paper provides the historical context for the extinctions, and shows they were inextricably linked to the expansion of the island's nascent phosphate industry. The endemic rats were killed off by a disease introduced with black rats R. rattus, which according to the mining company manager Captain Samuel Vincent, were bought to the island by the SS Hindustan that arrived in December 1899. However, historical sources including a photograph held in the National Archives of Australia, together with newspaper shipping intelligence and archival correspondence, all suggest that Captain Vincent was actually referring to the SS Hindoustan that visited the island in early September 1900. This shortens the period between alien introduction and endemic extinction from five years to four years. At the time, the arrival of black rats was noteworthy not for their impact on the native rats, but because they frustrated attempts at growing fresh food and were implicated in the appalling death toll of Chinese coolies during an outbreak of beriberi. This research corrects and adds to the century-old and widely reported account of these extinctions, and places the introduction of R. rattus in a broader historical context.