North American river otter

It is active by day or night, often around dawn and dusk. It uses habitats including rivers, streams, lakes, swamps, estuaries and coastal marshes. It feeds on fish, crayfish, crabs, frogs and other aquatic animals.

River otters swim with undulating body movements and a powerful tail, but they also travel considerable distances over land between waterways. Sliding on mud or snow can be play, travel or both.

Otters use scent-marking sites called latrines that can become information centres where multiple animals leave chemical signals.

Otters are high-level aquatic predators that link fish, crayfish and amphibian populations with the surrounding terrestrial food web. Their presence depends on functioning waterways with enough prey and cover.

An otter can close its ears and nostrils while diving and uses sensitive whiskers to detect movement in murky water.

Mating — can occur through much of the year.
Delayed implantation — the embryo can pause for months, so total time from mating to birth may be about 9–12 months.
Birth — usually 1–3 pups are born in a sheltered den, often in late winter or spring.
Dependency — pups remain with the mother for many months while learning to swim and forage.

• Keep dogs from chasing otters into water or cornering them on banks.
• Remove discarded fishing line and hooks from waterways.
• Use covered or secured fish-pond designs where losses are a concern.
• Slow down near wetland road crossings, where otters may travel between drainages.

• River otters eat only fish. They also take crayfish, frogs and other aquatic prey.
• Sliding means otters are wasting energy for fun. Play can be part of social behaviour and motor practice, and slides can also be efficient travel routes.
• An otter seen on land is lost. Overland travel between waterways is normal.

• least-weasel
• long-tailed-weasel
• American mink