The river otter is Minnesota’s largest aquatic carnivore that lives in most northern Minnesota lakes, ponds, and streams. It can swim and maneuver better than many fish and swims with only the top of its head out of the water. Otters are playful, often wrestling or spending hours sliding down muddy or snow-packed stream banks. They also play by nudging sticks across the water, and dropping pebbles to the bottom and retrieving them. North American river otters can remain underwater for nearly 4 minutes, swim at speeds approaching 7 mph, dive to depths nearing 20 yards, and travel up to 440 yards while underwater.
Habitat
Today, otters are common in all of northern Minnesota, and thanks to wetland restoration, are becoming more common again in southern parts of the state. The river otter can tolerate a great range of temperatures and elevations. A river otter’s main requirements are a steady food supply and easy access to a body of water. However, it is sensitive to pollution and will disappear from polluted areas.
Reproduction
Otter family life begins with mating in late winter/early spring. Most females don’t give birth until three years old, while males don’t usually breed successfully until five to seven years old. The female otter doesn’t dig her own den. She cares for her 1-3 pups in an existing structure, usually close to water. The cubs will remain with the parents through the first winter but separate the next spring.
Food
River otters primarily eat fish however river otters, as foragers, will immediately take advantage of other prey when readily obtainable. Other food river otters eat include fruits, reptiles, amphibians, birds, aquatic insects, small mammals, and mollusks. They have a very high metabolism, so they need to eat frequently.
Spotting One
An otter had dark brown fur on the back with a slightly lighter brown on the bottom with a white or greyish-silver throat/mouth area. You are most likely to spot an otter in a lake, river, or pond swimming around, relaxing on a log, or trying to catch food. While we were on Sawbill Lake in the BWCA we saw one while we were paddling around the lake and had another one run right through our campsite.