The river otter, Lutra canadensis , is an elusive aquatic mammal. It belongs to the mustelid or weasel family and is closely related to the sea otter, mink, badger, wolverine and weasels. Otters slide on ice or snow, shoot down slick muddy banks into creeks, play with food, sticks and stones, and wrestle each other. Few outdoor people are lucky enough to see otters in the wild, but those who do rarely forget the experience.
Females are slightly smaller.
An otter's tail is long and tapered, thickest where it joins the body and furred its entire length. The face is broad, and the eyes protrude slightly. In autumn, the normally thick fur grows in even thicker for extra cold resistance. All four feet are wide and webbed between the toes, although the hind pair are used more in swimming than the front pair. Otters obtain most of their food from the water.