River Otter

River otters (Lontra canadensis) are now found throughout most of Indiana, thanks to efforts of the DNR and its partners. In 1995, the DNR began a reintroduction program aimed at re-establishing a healthy otter population in several watersheds of northern and southern Indiana. After five years of reintroductions, the otter population began to expand through natural reproduction. The otter was removed from the state-endangered species list in 2005. Since that time, otters have been documented in more than 90 percent of Indiana counties, far surpassing reintroduction goals. The population continues to expand.

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General characteristics

• Otters have a long body, short legs and muscular neck.
• Fur color varies from light brown to almost black.
• Otters have long, thick whiskers and webbed feet.
• Weights range from 11 to 20 pounds.
• Otters can hold their breath for 8 minutes.
• Their fur repels water.
• Otters are most active at night and at dawn and dusk.

Similar species

• Mink
• Muskrat
• Beaver

Distribution and abundance

A total of 303 river otters were released in northern and southern Indiana between 1995 and 1999.

The reintroduction went so well that the river otter was removed from the state-endangered list in 2005. River otter reports have been documented in most counties in Indiana and river otter will likely be statewide, though in some places at low densities in the next several years.  Each year, DNR staff collect samples from river otter carcasses for population monitoring.

Reproduction

River otters are polygynous (have several mates). Most river otters will start reproducing at 2 years old. Otters typically breed from December to April and gestation is 61–63 days. Otters also delay implantation at least 8 months, meaning birth may not occur until 10 to 12 months after copulation. Litter size is typically one to three kits, however they can range up to five. The female otter raises the young without aid from the adult males. Young are born between February–April and can leave the den within eight weeks of birth.

Food habits

River otters spend most of their lives in water, which reflects in their diet. They primarily eat fish, especially slower-moving and abundant species, and crayfish, though they will also eat frogs, mussels, small mammals, salamanders, ducks and other birds, and other animals that hang around the water. Though primarily carnivores, river otters have been documented eating fruit on rare occasions.

Management and control

River otters and human conflicts

River otters can cause damage, especially to small fish ponds or fish hatcheries. If a landowner has damage occurring during trapping season, their best option is to allow a licensed trapper property access to try to alleviate the damage. Outside of the trapping season, landowners can contact the DNR to obtain a nuisance wild animal control permit. Damage has to be confirmed by a wildlife biologist before the permit can be issued. Otter damage in ponds can be reduced by providing adequate structure to afford ample places for fish to hide from predators like otter. Electric or welded-wire fencing can also be effective, depending on the size of the pond or hatchery.

Management

A limited river otter trapping season was initiated in 2015 after otters had greatly expanded in Indiana. The season is highly regulated, with mandatory 24-hour reporting, tagging requirements, season bag limits, and a season quota. Learn more about the river otter trapping season. River otters are tracked through several surveys, including harvest monitoring and monitoring incidental captures, as well as through Snapshot Indiana and the Archer’s Index survey. Reports from various surveys and monitoring are available on the wildlife reports page.