Rat species are either terrestrial or arboreal in nature, although rats preferring one habitat are capable of inhabiting others. The Norway rat and roof rat are the two most common North American rat species. They are terrestrial and arboreal, respectively.
Norway rats are most commonly burrowers. They build their nests outside the walls of homes or in various clumps of vegetation. Norway rats may also construct their homes beneath the edges of sidewalks or patios.
As is implied by their name, roof rats prefer arboreal habitats. They live in yucca, palm and cypress trees, as well as in elevated areas of human homes. Roof rats can be found living in attics, rafters, eaves and on roofs. They may also choose to nest in nonarboreal vegetation, such as shrubs, honeysuckle and tall grasses.