Northern River Otter

 

Otters having a blast while making a splash in Lake Superior.

NPS/ Paul Brown

An Otter Perspective

"Splash! A quick brown flash at the surface and down again I go. Swimming, swirling, searching for my next scrumptious snack. I find my home at the veil where land meets water. Isle Royale is filled with such places- if one were only to take a dip and look."

The Northern River Otter (Lontra canadensis) is equally at home in the water and on land and make their homes in a burrow near the water’s edge. River otters are found all throughout North America, inhabiting inland waterways and coastal areas.

 

Webbed feet are an adaptation river otters have that make them an excellent match for water.

NPS

Made for Water

Otters are not fast on land unless they find snow or ice where they hop and slide to gain speed. They are built for swimming and swim by propelling themselves with their powerful tails and flexing their long bodies. Otters can run fast, but not quite as well as they can swim. They will also move long distances between waterbodies for food and to avoid possible predators and disturbances.

• Otters find their favorite foods in water:
  • fish
  • amphibians
  • turtles
  • crayfish
• Otter aquatic adaptations:
  • Webbed feet
  • Water repelent fur
  • Nostrils and ears close in water
• Northern river otters have a maximum swimming speed of 15 miles per hour.

 

Behavior

• Active year-round
• Active mostly during twilight hours, however, can be seen at all times of the day.
• Breed in late March through April. 
• Have one litter per year. 
• Produce two young on average. 
• Offspring stay with mother otter until next year's litter.
• Offspring may temporarily join other family groups.
• Have litters in dens utilizing old muskrat burrows, beaver huts, and holes dug into tree roots along shorelines.

Numbers

• 22 to 42 inches in length
• Weigh 10 to 30 pounds
• Average lifespan is 8 to 9 years

 

Even otters find time to relax in the sun on the archipelago.

NPS/ Paul Brown

Otter Spotter

The northern river otter is the most aquatic member of the weasel family. Otters are commonly seen:

• Along the shorelines of inland lakes and Lake Superior exploring and hunting.
• Sunning themselves by the water’s edge.
• Occasionally on docks.

 

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  Beaver

  Beaver create important aquatic habitat for other island creatures.

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  Birds

  Different habitat types provide for a great diversity of birds.

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  Red Fox

  Isle Royale fox are curious canines that scavenge for their food.