North American river otter (Lontra canadensis) have returned from near extinction to urban stretches of the Mississippi River in the Twin Cities. River otters were nearly extirpated from Minnesota by the early twentieth century from pollution, habitat loss and trapping.
Their return to the Twin Cities is a success story for the Mississippi River, showing positive change in water quality and trapping regulations.
Threats to otters include "bio-accumulation" of pollutants in the food chain, road collisions, and loss of habitat from human development.
How We Study Otters
The National Park Service monitors river otter populations within the Mississippi National River and Recreation Area using several techniques.
Volunteers and biologists look for otter scat, tracks and other sign along shorelines in the fall and winter. Sign surveys started in 2009 and tell us which habitats otters use in the park, over time.
Remote cameras help us better understand population numbers and how otters interact with other wildlife and human development.
Last updated: April 23, 2020