Range of Movement of Some Malayan Rats

Abstract

Although accounts of experiments involving the trapping and retrapping of marked rodents are now numerous, no such studies seem to have been made of the many species of rats in Southeast Asia. Experiments of this sort have recently been carried out in Malaya on rats which are the hosts of the chiggers which transmit mite-typhus (scrub-typhus). Unlike most such studies, interest was centered rather on differences between species than on differences between individuals of the same species, and a method was sought of expressing an “average” home range for such species. In attempting to do this it became clear that the customary methods of estimating home range, such as those summarized by Stickel (1954), were not in fact applicable to the problem, since the “ home range,” as usually understood, could not be exactly delimited. The concept of the home range has, therefore, been replaced, for this purpose, by the concept of a series of probability contours surrounding a center of activity, and what appears to be a new way of calculating and expressing the result has been evolved. The major hosts of the trombiculid mites which convey mite-typhus are, in Malaysia, rats of the genus Rattus . Some account of the various mammals involved has previously been given in these pages (Harrison and Traub, 1950) and elsewhere (Audy and Harrison, 1954), while a detailed study of their habitat preferences has been published recently (Harrison, 1957). The species involved in the present account are: Rattus jalorensis (Bonhote), Malaysian wood rat. A member of the white-bellied Rattus rattus group, confined to cleared land and secondary forest, with a decided preference for the edges of woodland. Rattus argentiventer (Robinson & Kloss), ricefield rat. Also a member of the Rattus rattus group, confined to grassland and ricefields. Rattus exulans (Peale) = R. …