River Otter (Lutra canadensis) adult. Playful fishers, river otters are at home both on land and in the water. They have thick durable fur and were trapped for the fur trade from the earliest colonial period. They will frolic with family and alone, rolling about, sliding on mud, snow, and ice, and body surf in rapid moving waters. They primarily eat slow-moving fish rather than game fish which are harder to catch. Timucuan Preserve, Duval County, Florida.