Rat Plagues in Western Queensland

Abstract

PLAGUES of native species of rodent recur from time to time in the dry inland plains of Australia1,2,3,4. Palmer3 describes an outbreak of rats (apparently the long-haired rat, Rattus villosissimus Waite4) which occurred after continuous rains during 1869–70, and moved northwards across the Gulf Country plains from the head of the Flinders River (Fig. 1). There was a corresponding increase in native dogs, snakes, hawks and owls which, together with the exhaustion of the food supply, the drying of the grass at the end of the season and their own cannibalism, brought the plague to an end. Evidence of previous plagues was found in "hollow trees, in which owls had lived for years, [which] were filled with the bones and skulls of millions of rats". Troughton4 (p. 286) observed another outbreak of R. villosissimus on the Barkly Tableland in 1934. I have been unable to obtain records of plagues on the plains of Central Western Queensland further back than the beginning of this century; but since then R. villosissimus has erupted here at intervals of approximately eleven years, in 1907, 1918, 1930–31 and 1940–42. Each time the rats travelled in a roughly south-easterly direction. During April–June 1907 they moved at night on a 150-mile front south and south-east from the Flinders River, and were followed by large numbers of wild domestic cats and dingoes1. In this year, and in 1918, it was observed that practically all those trapped were males1.