The black rat, Rattus rattus, is not native to North America, but rather to the Old World. Unfortunately, the species has been accidentally introduced to many areas of the world (it escaped from ships at port) where it has sometimes had devastating effects on native species. The black rat is still especially common around seaports, but it has moved to many inland areas as well. Black rats are associated with man, usually living in buildings or in fields near buildings. The species is not common in Utah.
Black rats are opportunistic feeders that will consume both plant and animal material. The species breeds throughout the year. Gestation takes approximately three weeks, and females produce multiple litters of about eight young each year. Black rats are active year-round, mainly at night. Unlike Utah's native woodrats, black rats have scaly (hairless) tails.