In Australia, eucalypt forests are the major vegetation form. They are highly fire-prone, but also the major repository of the vertebrate fauna. Recent studies have demonstrated that the fauna, like the flora, may be adapted to fire. Simple divisions of environments into habitats satisfactorily predicted the abundance and diversity of small mammals. The habitat preferences of four species of small mammal were examined in relation to various components of the habitat using principal component analysis. The environmental components scored were the abundance of litter, brush and boulders, of ground vegetation, and of shrubs, and of trees and their canopies. The patterns which emerged are examined for projected effects of fires of high or low intensity upon the habitat components and hence upon the small mammal fauna.