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Species Description

• Adult total length: 12 1/2 - 16 1/2 in. (325 - 425 mm)

• Tail: 7 1/2 - 9 1/2 in. (190 - 240 mm)

• Hind foot: 1 3/8 - 1 1/2 in. (35 - 38 mm)

• Weight: 5 - 10 oz. (140 - 280 g)

• Physical Characteristics: The black rat is a medium-sized, slender brownish-or grayish-black rat with coarse fur and a long, sparsely haired, scaly tail. The tail is longer ( approximately 110 percent) than the combined length of the head and body. This feature serves as a key identification character in differentiating this species from the Norway rat. The underparts are grayish-white.

left lateral view of skull and mandible	dorsal view of skull	ventral view of skull

The black rat is a non-native (exotic) species that is thought to have arrived in North America in the mid-1500's on the ships of early European explorers. It is native to Asia Minor and the Orient (Walker, 1964). The black rat is found primarily around human habitatations, mainly in coastal areas from Massachusetts to British Columbia and throughout much of Mexico. It is abundant in the southeastern United States, particularly in seaports.

• Range Maps

  Great Smokies

• Great Smoky Mountains National Park: This species was reported to be abundant around barns in Greenbrier by Komarek and Komarek (1938), but it is now an uncommon resident of the park.
  • Sevier Co.: Park headquarters; Little River near Metcalf Bottoms (1,800 feet); Greenbrier (1,680 - 2,000 feet); Elkmont (2,150 feet); Mt. LeConte (6,300 feet).

  • Swain Co.: Smokemont (2,200 feet).

Index

Natural History

• Reproduction
  Black rats are prolific, but they produce smaller and fewer litters than the Norway rat. After a gestation period of approximately 22 days, an average litter of about six young are born. It has been estimated that each adult female produces approximately 40 young per year (Linzey, 1998). In the park, breeding probably occurs throughout the warmer months of the year.

  Young black rats mature rapidly and are weaned when about three weeks old. They are able to reproduce at approximately three months of age.

• Longevity
  Wild individuals have been known to live for over a year, whereas captives have survived for over four years (Linzey, 1998).

• Terrestrial Ecology
  Black rats are active throughout the year and do not hibernate. They are mainly nocturnal. Their sense of sight is poor and they are colorblind, but their senses of smell, taste, touch, and hearing are excellent (Jackson, 1982). The black rat is less aggressive than the Norway rat and is driven out of certain areas by its larger relative.

  Black rats apparently live in a very restricted area. Stroud (1982) reported an average home range of 0.19 ha. Jackson (1982) noted an average home range radius of 50 m.

• Predators and Defense
  Snakes, hawks, owls, and most carnivorous mammals are potential predators of black rats.

• Parasites
  None recorded from the park.

• University of Michigan, Museum of Zoology
• eNature

Index

Acknowledgements

• Text
  • Dr. Donald W. Linzey, Wytheville Community College - wclinzd@wcc.vccs.edu
  • Christy Brecht, Wytheville Community College - wcbrecc@wcc.vccs.edu

• Photographs
  • Roger Barbour

• Map development
  • Richard Schulz, Great Smoky Mountains National Park - richard_schulz@nps.gov

• Web page design & coding
  • Denise Lim, University of Georgia, Athens
  • John Pickering, University of Georgia, Athens

• Jackson, W. B. 1982. Norway rat and allies. Pages 1077-1088. In: J. A. Chapman and G. A. Feldhamer (eds.). Wild Mammals of North America. Baltimore: The Johns Hopkins University Press.

• Komarek, E.V. and R. Komarek. 1938. Mammals of the Great Smoky Mountains. Bulletin of the Chicago Academy of Sciences 5 (6): 137-162.

• Linzey, D. W. 1995a. Mammals of Great Smoky Mountains National Park. Blacksburg, Virginia: The McDonald & Woodward Publishing Company, Inc.

• Linzey, D. W. 1995b. Mammals of Great Smoky Mountains National Park-1995 Update. Journal of the Elisha Mitchell Scientific Society 111(1):1-81.

• Linzey, D.W. 1998. The Mammals of Virginia. Blacksburg, Virginia: The McDonald & Woodward Publishing Company, Inc.

• Stroud, D.C. 1982. Population dynamics of Rattus rattus and R. norvegicus in a riparian habitat. Journal of Mammalogy 63(1): 151-154.

• Walker, E.P. 1964. Mammals of the World. 3 volumes. Baltimore: The Johns Hopkins University Press.