IUCN Otter Specialist Group . . . leading global otter conservation Last Update: Sunday February 22, 2015
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Lontra canadensis (Shrebber, 1776), the North American River Otter (currently being revised)



A large, sturdy otter, 1.5m long, weighing 15kg. The paws are webed to the end, with tufts of hair under the toes; the claws are strong. The rhinarium is large and diamond-shaped, the muzzle broad and well-whiskered. In general, this species is dark brown on the upper surface, sometimes with frosting, and paler below and on the face. There is a great deal of regional variation, with many subspecies. This species shows variable sociability - some animals are solitary, others live in fairly stable pairs, some families join together while hunting, and all of this can vary seasonally. These otters exhibit delayed implantation - while the gestation is around the normal otter 63 days, breeding takes place once a year in late winter/early spring, depending on latitude. This species also has a characteristic "chuckle" vocalisation. These otters mainly eat a wide variety of fish, but in different locations and seasons, amphibia, muskrats and birds may be important. Crayfish and mussels are also taken. Liers reported that his many pet otters had a passion for blueberries and would patiently strip a bush if encountered during a walk.

CITES Identification Sheet


These otters are found in a huge variety of habitats from coastal waters, swamps and lowland rivers, creeks and streams to mountainous areas - wherever there is sufficient food and suitable den sites.


North America: Canada (Alberta; British Columbia; Labrador; Manitoba; New Brunswick; Newfoundland; Northwest Territories; Nova Scotia; Nunavut; Ontario; Quebec; Saskatchewan; Yukon) and USA ( (Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; District of Columbia; Florida; Georgia; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming)

Conservation Status

Red List Category LC (Least Concern)
Year Assessed 2008
Assessor Serfass, T. & Polechla, P.
Evaluators Hussain, S.A. & Conroy, J. (Otter Red List Authority)

Improvements in water quality and trapping management, along with a reintroduction effort has enabled this species to recover from the low numbers of the early 19th century.

(Source: IUCN Red List)

Current Concerns

Since 1976 over 4,000 otters have been reintroduced among 21 states. Also, 29 states and all Canadian provinces except Prince Edward Island have viable populations that sustain annual harvests. Current harvest strategies do not pose a threat to maintaining otter populations. However, harvest may limit expansion of otter populations in some areas. Oil spills present a localized threat to otter populations, especially in coastal areas. Water pollution and other degradation of aquatic and wetland habitats may limit distribution of otters and pose long-term threats if enforcement of water quality standards are not maintained and enforced. Acid drainage from coal mines is a persistent water quality problem in some areas that eliminates otter prey prevents thereby inhibits recolonization or expansion of otter populations. Recently, there has been discussion of the long-term genetic consequences of reintroduction projects on remnant otter populations (Serfass et al. 1998). The threat of disease to wild otter populations is poorly understood and has received little study (Serfass et al. 1995). Similarly, many perceived threats to otters such as pollution and habitat alterations have not been rigorously evaluated. Additional research is needed to clearly delineate the impact that various forms of water pollution, agricultural and other development along riparian habitats, industrial and housing development in coastal areas, cumulative impacts related to loss or alterations of wetlands, large flood control structures, and interactions that these and other factors have on otter populations. Threats to otter populations in North America vary among regions and are influenced by type, distribution, and density of aquatic habitats and characteristics of human activities.

Leading Researchers

Tom Serfass, Paul Polechla, Wayne Melquist,

Key Publications


  • Harris, C.J. (1968). Otters: A Study of the Recent Lutrinae. Weidenfeld and Nicholson, London
  • Melquist, W.E. and Dronkert, A.E. (1987). River otter. In: M. Novak, J. Baker, M.E. Obbard and B. Malloch (eds) Wild furbearer management and conservation in North America. Ontario Ministry of Natural Resources, Ontario, Canada.
  • Polechla, P. (1990). Action plan for North American otters. In: P. Foster-Turley, S. Macdonald and C. Mason (compilers) and the IUCN/SSC Otter Specialist Group Otters: an action plan for their conservation, pp.74-79. IUCN, Gland, Switzerland.
  • Ralls, K. (1990). Reintroductions. In: P. Foster-Turley, S. Macdonald and C. Mason (compilers) and the IUCN/SSC Otter Specialist Group Otters: an action plan for their conservation, pp.20-21. IUCN, Gland, Switzerland.
  • Serfass, T.L., Brooks, R.P. and Rymon, L.M. (1993). Evidence of long-term survival and reproduction by translocated river otters, Lutra canadensis. Canadian Field Naturalist 107:59-63.
  • Serfass, T.L., Brooks, R.P., Novak, J.M., Johns, P.E. and Rhodes Jr., O.E. (1998). Genetic variation among populations of river otter in North America: considerations for reintroduction projects. Journal of Mammalogy 79:736-746.
  • Serfass, T.L., Whary, M.T., Peper, R.L., Brooks, R.P., Swimley, T.J., Lawrence, W.R. and Rupprecht, C.E. (1995). Rabies in a river otter intended (Lutra canadensis) for reintroduction. Journal of Zoo and Wildlife Medicine 26:311-314.
  • Toweill, D.E. and Tabor, J.E. (1982). The northern river otter. In: J.A. Chapman and G.A. Feldhamer (eds) Wild mammals of North America: biology, management and economics, pp.688-703. Johns Hopkins University Press, Baltimore, Maryland.

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