Mortality and Movement of Brown Rats (Rattus norvegicus) in Artificially Supersaturated Populations

Abstract

Three expts. are described in which alien rats were introduced into stable populations which presumably represented the maximum number of rats capable of being supported by the areas. City blocks were the units of area investigated. Half the surviving introduced rats established themselves near their point of release; the others returned to their home block if it was an adjoining block. In these artificially induced high population levels, mortality increased, being 2-3 times as great for alien as for native rats.