The black rat is slightly smaller than the Norway rat, but much larger than the house mouse, the only other members of the subfamily in Oregon. The black rat is similar to other members of the subfamily in that it possesses a scaly, scantily haired tail; membranous, nearly naked ears, and a soft pelage. It differs from the Norway rat in having a tail much longer than the length of its head and body and commonly having a darker-colored pelage. The pelage ranges from black to sandy brown dorsally and from lead colored to nearly white ventrally.

The black rat occurs nearly worldwide. It is a native of southeastern Asia. In Oregon, it has been found in Portland, Salem, and several smaller cities along the Coast. These rats are restricted largely to port cities and coastal regions in Oregon, where they are associated with human enterprises/ wharves; piers; dockside warehouses; piles of crates, nets, traps and debris; barns; houses; and waterfront stores. Feral populations of the species also inhabit wet coastal forests in some areas.

Black rats are agile climbers and accomplished wire-walkers. Individuals in feral populations build nests of twigs and leaves in a log stump, or in the crouch of a tree.

Photo from Wikipedia