River Otter
Scientific Name: Lontra canadensis
The river otter is a large member of the weasel family well-adapted for aquatic life with webbed feet, a strong tail, glossy fur, and closeable nostrils and ears. Otters are generally brown in color (ranging from light brown to black) with a lighter greyish color on the chin and throat. They have a broad head, stout body, and short legs.
Adult size: 35-51” in length with males larger than females. The tail comprises 1/3 their length.
Weight: 10-30 lbs
Life span: 20 years in captivity, usually less than 10 in the wild
Maturity: 1 to 2 years
Litter size: 1-6, usually 1-3
Fun Fact:
Otters use their long whiskers to sense motion in cloudy water to help capture fish!
Diet
They are carnivores and may be considered an aquatic generalist. They primarily eat fish, with amphibians, reptiles (hibernating turtles), aquatic invertebrates (including crustaceans like crayfish), small mammals (primarily small muskrats), and birds being a lesser component of their diet.
Habitat
River otter may be found in ponds, lakes, rivers, streams, marshes, and inland wetlands including beaver ponds. They typically use habitat with a lot of emergent vegetation and areas with high quality riparian corridors.
Behavior
Otters den near water and will often use an underwater entrance. They may use burrows of other animals or den in hollow logs, beaver lodges, log jams, rocky areas, and under root masses. They are primarily nocturnal with some activity during the day, especially during winter. They are active year-round and do not hibernate.
Most adults are solitary outside of the breeding season, with a female and her young comprising the core family group, occasionally accompanied by her mate or another adult once young are weaned. Families of otters avoid one another and use latrine sites (toilet areas on exposed rocks, logs, or banks above the water) to signal presence in an area. Seasonal home ranges are roughly span 3 to 10 miles of shoreline.
Reproduction and Life Cycle
River otters may breed in late winter through early spring. Females have delayed implantation and young are born after around 2 months of gestation in spring, usually April or May. Young are born blind and open eyes after 30-40 days and may take short ventures out of the den 10 days later. Young are weaned after 3-4 months and adult otters feed young for 40 weeks. Juveniles disperse after around 12-13 months.
Population Status
River otters were historically present in all New York watersheds but declined due to unregulated harvest, habitat loss, and water pollution. Otter slowly increased in numbers in the eastern part of the state after protections were established in 1936. They were still absent from the western part of the state until a reintroduction effort in the latter half of the 1990’s restored them. They are still threatened by bioaccumulation of toxins from consuming large quantities of fish.
Viewing
River otters are hard to find, your best chance may be visiting areas where slides (chutes in the snow from a bank down into a waterway made by sliding otters) are found in winter or latrines in summer.
Range
River otter occur throughout most of the state.
For more information on River Otter in New York please visit the NYSDEC page here.