River Otter Overview

2 otters

River Otters
The playful North American river otter (Lontra canadensis) used to be common in the Upper Mississippi River Basin and throughout North America. One hundred years ago, unregulated trapping and habitat loss due to pollution and city growth in the US and Canada nearly caused the otter to go extinct.

Improvements in water quality, hunting/trapping regulation and reintroduction efforts in the 1980s have allowed their populations to recover and grow. In fact, there have been numerous recent sightings within the Mississippi National River and Recreation Area and in lakes nearby.

Otter Sign Surveys
In 2009, due to frequent reports of otter sightings in the park, the National Park Service conducted a pilot "sign survey" to look for traces of otter presence within the Mississippi National River and Recreation Area. In 2010 and 2011, further winter studies were conducted, confirming the presence of otters in the park.


A ranger points to an otter slide trail

Background on Otters
Otters mostly eat fish, but will also eat plants, insects, small mammals, snails, and mussels. They have few natural predators. Importantly, otters regulate aquatic ecosystems so that other fish and animals don't overpopulate. Their position at the top of the food chain also puts them at risk for absorbing more pollutants than other organisms, through a process called "bio-accumulation."

Otters spend most of their time playing and hunting. These aquatic mammals are well adapted to living in the water with their streamlined bodies, webbed feet and dense, shiny fur. While otters can be observed at any time of the day, they are most active at night and are often shy and elusive. One of the best ways to look for otters is to look for their footprints or scat. In the winter, you can often find their sliding tracks and footprints in the snow.

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