This week on Discover Nature, watch for river otters on frozen water.
Well suited for life in water, otters have streamlined bodies, fully webbed feet, and long, tapered tails. Dense, oily fur and heavy layers of body fat keep them insulated.
Otters are graceful, powerful swimmers and can remain submerged for three to four minutes. On land, they travel with a loping gait, and on snow or ice, they alternate loping with sliding.