An Ecological Study of the Norway Rat and the House Mouse in a City Block in Lawrence, Kansas

Abstract

Rodents of the family Muridae which have been introduced in North America are Rattus rattus, Rattus norvegicus, and Mus musculus; of these, the brown or Norway rat (Rattus norvegicus) and the house mouse (Mus musculus) are the subjects of this study. For centuries these rodents have been closely associated with man and his culture. It is well known that in the temperate and tropical regions these animals have accompanied man and have become established wherever he has settled. Within the limits of the United States, two or more of these rodents have been found in every state. Tryton (1947) reports that Montana was the last state to become infested with the brown rat and that the animal was evidently introduced there several times before becoming established. Tryton surmises that the relatively sparse human population in Montana (2.3 persons per square mile in rural areas in 1940) was a factor that delayed the rats in becoming established. These non-native rodents have been much used in experimental laboratory work and have been studied extensively in problems that are related to public health. Nevertheless, there has been surprisingly little research done concerning the home range and movements of these rodents in their adopted habitats. The principal studies concerning non-native rodents have been made in connection with rodent control by the United States Public Health Service and other governmental agencies. However, in the past few years, studies of population fluctuations, home range, and other life habits of these rodents (chiefly Rattus norvegicus) have been initiated both in the United States and in England. Davis, Emlen and Stokes (1948), working in Baltimore from 1943 to 1948, made extensive studies of the Norway rat, including observations of its home range. In addition, they cited the findings of other workers, pointing out the small amount of information available concerning these animals. Other reports make some mention of movements of non-native rats and mice. In 1932-33 Kalabukhov and Raevskii (in Elton, 1942:85) ringed 928 house mice which lived in grain stacks in the Petrovsk District of North Caucasus. Mice were captured at four localities, 5001000 meters apart. Within six weeks 189 were recaptured at the points