Abstract
The percentages of animal materials and crude fiber in the stomachs of the Norway rats indicated that their diet consisted of more variable proportions of those materials in different localities or individuals than that of the roof rats. Thus the Norway rat should be more appropriately called omnivorous, whereas the roof rat is herbivorous or, more precisely, a fruit-and seed-eater, because it selects a large amount of fruits and seeds (51-59%). In the main feeding places in rural areas such as storehouses and storerooms, there generally are present products suitable for diet of roof rat. On the other hand, in the main feeding places in urban areas, i.e.most likely drainage systems connected to kitchens as well as kitchens themselves, there were probably present edible garbage suitable for the diet of the Norway rat, a successful denizen of sewers. Thus they segregated their habitats in each locality. In the forest area in Miyake-jima Is. cohabited by the two species, each species preferred a different diet. Their direct inter specific interactions possibly occurred in a livestock experiment station because the assorted feed represented main diets for both species.
