Ondatra zibethicus
ITIS Species Code:   180318         NatureServ Element Code:   AMAFF15010
NatureServe Global Rank: 
NatureServe State (NC) Rank: 
Federal Status: 
NC State Status: 
Land Unit

US Fish & Wildlife Service
US Forest Service
US National Park Service
US Department of Defense
NC State Parks
NC University System
NC Wildlife Res. Com.
NC Forest Service
NC Div. of Coastal Mgmt.
Local Governments
Non-Governmental Org.
Other Public Lands
Private Lands

GAP Status 1-2
All Protected Lands




% of Dist. on
Prot. Lands

21.8 %
10.7 %
18.8 %
6.9 %
8.2 %
1.5 %
19.5 %
1.0 %
2.9 %
6.2 %
6.2 %
0.3 %
< 0.1 %

57.2 %
% of Dist. on
All Lands

1.3 %
0.6 %
1.4 %
0.4 %
0.5 %
< 0.1 %
1.2 %
< 0.1 %
0.2 %
0.1 %
0.4 %
< 0.1 %
93.6 %

3.5 %
Muskrats are abundant from the Chesapeake tidewaters of Virginia down to northeastern North Carolina (Webster et al. 1985). They are less common to rare in the mountains, piedmont and southern portions of the coastal plain (Lee et al. 1982). Most individuals in the mountains have been observed in valley areas at elevations below 2400ft (Linzey and Linzey 1971).

Muskrats prefer the tall vascular, non-woody plants of fresh or brackish water marshes for food and lodge building material (Whitaker and Hamilton 1998). Like beavers, muskrat lodges are built in shallow aquatic habitats. However, building material is predominantly of the reeds and sedges of the marsh. They are less abundant in wooded waterways, lakes, ponds and swamps, where they regularly burrow into waterside embankments rather than construct lodges (Webster et al. 1985).


Prefers fresh or brackish marshes, lakes, ponds, swamps, and other bodies of slow-moving water. Most abundant in areas with cattail. Rare or absent in large artificial impoundments where fluctuating water levels eliminate littoral zone plants (food supply) (Caire et al. 1989). Dens in bank burrow or conical house of vegetation in shallow vegetated water. Sometimes in uplands-Clough 1987.

See Clark (1994) for information on habitat selection in experimental marshes undergoing succession in Manitoba.

Occupied Landcover Map Units:
Code NameDescription NC Natural Heritage Program Equivalent
3 Tidal Marsh Fresh and brackish tidal marshes, including cord grass, wild rice, sawgrass and needlerush alliances. Brackish Marsh, Interdune pond, Maritime wet grassland
75 Tidal Swamp Forest Swamp tupelo dominated forest with or without black tupelo and/or cypress trees. Restricted to the tidal zones in the coastal plain. May have inclusions of coastal red cedar woodlands. Tidal cypress - gum swamp
380 Coastal Plain Fresh Water Emergent Emergent vegetation in fresh water seepage bogs, ponds and riverbeds of the coastal plain. Includes alliances dominated by sedges, eelgrass, as well as cane found in unforested cane-brakes. Small Depression Pond, Sandhill Seep, Floodplain Pool, Unforested Floodplain Canebrake, Riverscour Prairies, Vernal Pools
173 Coastal Plain Riverbank Shrubs Shrub dominated riverbanks, commonly dominated by willows and/or alders. Sand and Mud Bar
50 Coastal Plain Mixed Bottomland Forests Includes forests dominated by a variety of hardwood species, including sweetgum, cottonwood, red maple. Coastal Plain Bottomland Hardwood (in part), Coastal Plain Levee Forest
49 Coastal Plain Oak Bottomland Forest Bottomland forests dominated by deciduous oak alliances. Oaks represented can include swamp chestnut, cherrybark, willow, and/or overcup oak. Inclusions of loblolly pine temporarily flooded forests occur in patches. Hydrology is temporarily to seasonally flooded. Coastal Plain Bottomland Hardwoods (in part) blackwater subtype, brownwater subtype
30 Cypress-Gum Floodplain Forests Swamps dominated by black or swamp tupelo with or without Taxodium. Seasonally to semi-permanently flooded hydrology. Cypress-Gum Swamps
78 Pond-Cypress - Gum Swamps, Savannas and Lakeshores Cypress dominated swamps and lakeshores. Can include bays dominated by pond cypress or shorelines of coastal plain lakes with a narrow band of cypress. Non-riverine Swamp Forest, Natural Lakeshores (in part)
385 Oak Bottomland Forest and Swamp Forest The swamp chestnut oak, cherrybark oak, shumard oak and sweetgum alliance is one representative. Other alliances are dominated by water, willow, and overcup oaks. Swamp forests can be dominated by sweetgum, red maple, and black gum being dominant. Loblolly can occur in combination with sweetgum and red maple, or with tulip poplar. Includes saturated and semi- to permanently flooded forests in the mountains. Piedmont/Mountain Bottomland Forest, Piedmont/Mountain Swamp Forest
238 Piedmont/Mountain Submerged Aquatic Vegetation Seasonally to permanently flooded areas with aquatic vegetation. Waterlily, pondweed, hydrilla smartweed are a few of the species that can occur. Piedmont/Mountain Semipermanent Impoundment (in part)
239 Piedmont/Mountain Emergent Vegetation Emergent vegetation of all wetland hydrologies. Sites would commonly support species such as tussock sedge, rushs, and cattail alliances. Rocky Bar and Shore (in part)
267 Riverbank Shrublands Riverside shrubs with temporarily flooded hydrologies. Found in the both the Mountains and Piedmont. Containing dominants such as smooth alder and a Carolina or black willows. Sand and Mud Bar
269 Floodplain Wet Shrublands Saturated shrublands of the Piedmont, includes buttonbush, swamp-loosestrife, decodon and alders. Piedmont/mountain Semipermanent Impoundment
384 Piedmont/Mountain Mixed Bottomland Hardwood Forests Includes temporarily to seasonally forests dominated by hardwood species. Hardwoods include sweetgum, red maple, sycamore which co-occur in a mosaic of bottomland and levee positions. Includes alluvial hardwood forests in the mountains. Hemlock and white pine may occur as inclusions, but are generally mapped separately. Piedmont/Mountain Alluvial Forest, Piedmont/Mountain Levee Forest
205 Agricultural Pasture/Hay and Natural Herbaceous Farm fields used for pasture grass or hay production, as well as old fields dominated by native and exotic grasses. No equivalent
8 Open water Open water without aquatic vegetation. No equivalent
517 Hemlock Floodplain Forest Alluvial forest with hemlock and/or white pine in mountains and western piedmont. Hydrology is generally temporarily to seasonally flooded. Canada Hemlock Forest
View Entire Landcover Legend
Additional Spatial Constraints:
Exclude all area outside of known range.
Exclude all land greater than 50 meters from an open water feature.
Exclude all water greater than 50 meters from land.
Exclude salt water habitats.
Limited to elevation range: less than 2400 ft.
Johnson, C.E. 1925. The muskrat in New York:Its natural history and economics. Roosevelt Wildlife Bull., 3(2):205- 320.

Stewart, R.W. and J.R. Boder. 1977. Summer activity of muskrats in relation to weather. J. Wildl. Mgmt. 41:487-499.

Willner, G.R., G.A. Feldhammer, E.E. Zocker, and J.A. Chapman. 1980. Ondatra zibethicus. Am. Soc. Mamm., Mammalian Species No. 141. 8 pp.

Perry, H. R., Jr. 1982. Muskrats (ONDATRA ZIBETHICUS and NEOFIBER ALLENI). Pages 282-325 in J. A. Chapman and G. A. Feldhamer, editors. Wild mammals of North America. Johns Hopkins Univ. Press, Baltimore.

Marinelli, L., and F. Messier. 1993. Space use and the social system of muskrats. Can. J. Zool. 71:869-875.

Hollister, N. 1911. A systematic synopsis of the muskrats. North American Fauna 32:1-47.

Clark, W. R., and D. W. Kroeker. 1993. Population dynamics of muskrats in experimental marshes at Delta, Manitoba. Can. J. Zool. 71:1620-1628.

Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal Species of the World:a Taxonomic and Geographic Reference. Second Edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp.

Whitaker, J.O. Jr. and W.J. Hamilton, Jr. 1998. Mammals of the eastern United States. Cornell Univ. Press, Ithaca, New York. 583 pp.

Hanson, J. M., W. C. Mackay, and E. E. Prepas. 1989. Effect of size-selective predation by muskrats (ONDATRA ZIBETHICUS) on a population of unionid clams (ANODONTA GRANDIS SIMPSONIANA). J. Anim. Ecol. 58:15-28.

Neves, R. J., and M. C. Odom. 1989. Muskrat predation on endangered freshwater mussels in Virginia. J. Wild. Manage. 53:934-941.

Clark, W. R. 1994. Habitat selection by muskrats in experimental marshes undergoing succession. Can. J. Zool. 72:675-680.

Errington, P.L. 1961. Muskrats and marsh management. Stackpole Co., Harrisburg, PA. 183 pp.

Lee, D. S., L. B. Funderburg Jr., and M. K. Clark. 1982. A distributional survey of North Carolina mammals. Occasional Papers of the North Carolina Biological Survey, No. 1982-10. North Carolina State. Mus. Nat. Hist., Raleigh, North Carolina. 72 pp.

Errington, P.L. 1963. Muskrat populations. Iowa State Univ. Press, Ames. 665 pp.

Linzey, Alicia V., & Donald W. Linzey. 1971. Mammals of the Great Smoky Mountains National Park. The University of Ten- nessee Press, Knoxville, Tennessee. 114 p.

Banfield, A.W.F. 1974. The mammals of Canada. University of Toronto Press, Toronto.

Godin, A.J. 1977. Wild Mammals of New England. Johns Hopkins University Press, Baltimore. 304 pp.

Hamilton, William J., Jr., and John O. Whitaker, Jr. 1979. Mammals of the eastern United States. Cornell Univ. Press, Ithaca, New York. 346 pp.

Hall, E. R. 1981. The Mammals of North America. Second edition. 2 Volumes. John Wiley and Sons, New York, New York.

Schwartz, Charles W., and Elizabeth R. Schwartz. 1981. The wild mammals of Missouri. University of Missouri Press, Columbia. 356 pp.

Baker, Rollin H. 1983. Michigan mammals. Michigan State University Press. 642 pp.

Webster, W. D., J. F. Parnell and W. C. Biggs Jr. 1985. Mammals of the Carolinas, Virginia, and Maryland. The University of North Carolina Press, Chapel Hill, NC.

Clough, G. C. 1987. Ecology of island muskrats, ONDATRA ZIBETHICUS, adapted to upland habitat. Can. Field-Nat. 101:63-69.

Caire, W., J. D. Tyler, B. P. Glass, and M. A. Mares. Z. Marsh (illustrator). 1989. Mammals of Oklahoma. University of Oklahoma Press, Norman. Oklahoma. 567 pp.

10 March 2005
This data was compiled and/or developed by the North Carolina GAP Analysis Project.

For more information please contact them at:
NC-GAP Analysis Project
Dept. of Zoology, NCSU
Campus Box 7617
Raleigh, NC 27695-7617
(919) 513-2853