North American River Otter - Geographic Range

Geographic Range

The Northern American river otter is found throughout North America, inhabiting inland waterways and coastal areas in Canada, the Pacific Northwest, the Atlantic states, and the Gulf of Mexico. River otters also currently inhabit coastal regions throughout the United States and Canada. North American river otters also inhabit the forested regions of the Pacific coast in North America. The species is also present throughout Alaska, including the Aleutian Islands, and the north slope of the Brooks Range.

However, urbanization and pollution instigated reductions in range area. They are now absent or rare in Arizona, Hawaii, Indiana, Kansas, Kentucky, Nebraska, New Mexico, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, and West Virginia. Reintroduction projects have expanded their distribution in recent years, especially in the Midwestern United States. In 2010, the Colorado Department of Wildlife reported the species, reintroduced in the 1980s, was "thriving" and recommended its protection status be reconsidered. In Canada, North American river otters occupy all provinces and territories, except for Prince Edward Island.

Historical records indicate river otters were once populous throughout most major drainages in the continental United States and Canada prior to European settlement. North America’s largest otter populations were found in areas with an abundance and diversity of aquatic habitats, such as coastal marshes, the Great Lakes region, and glaciated areas of New England. In addition, riverine habitats in interior regions supported smaller, but practical, otter populations. The otter existed on all parts of the Pacific Coast, including the seashore and inlands streams and lakes. However, large populations never occurred in areas of Southern California such as the chaparral and oak woodlands and Mojave Desert seasonal waterway regions, or in the xeric shrubland regions in New Mexico, Texas, Nevada, and Colorado. In Mexico, the otters lived in the Rio Grande and Colorado River Deltas.