THE ANIMAL FILES

North American river otter

Lontra canadensis

Whiskers help a swimmer find food where vision alone is limited.

The North American river otter hunts aquatic and semiaquatic prey with a streamlined body, tapering tail and sensitive whiskers. It moves between water and shore, taking fish and other animals according to what is available.[1]

Follow the evidence ↓
North American river otter
Image: Jeremy T. Hetzel from Boston, USA · Commons · CC BY 2.0
Whiskers
Used to detect prey in dark water[1]
Eyes
A transparent inner eyelid protects them[1]
Food
Fish, crayfish, frogs and other prey[1]

Sensing near the face

Long whiskers supply information about prey in dark water. A transparent inner eyelid protects the eyes while swimming. Several sensory and protective structures therefore work alongside the swimming body.[1]

Different teeth for different food

Sharp canines and slicing teeth help handle animal prey, while broad molars can crush hard material such as shells. The recorded diet includes fish, frogs and crayfish, rather than a single universal prey species.[1]

Alone or with company

River otters can hunt alone or in pairs. Chasing and wrestling also occur between individuals, and scent marks make their presence known at particular sites. A social encounter can therefore involve several behaviours besides feeding.[1]

A COMMON MIX-UP

Does every river otter meal consist of fish?

No. Fish are important, but crayfish, frogs and other animals also occur in the diet.[1]

TRY A LITTLE REASONING

Why might whiskers matter when the water is dark?

Reveal the explanation

They provide close-range sensory information for detecting prey when visual information is limited.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — North American river otter (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Lontra canadensis (identity and classification)

Last fact check:

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