North American River Otter

The North American River Otter were almost eliminated in Missouri a century ago, due to unregulated harvest. In the early 1980’s and 1990’s there were restorative efforts which included releasing more than 800 otters throughout the state. Due to these efforts, otters are found all through Missouri.

River otters are perfectly created for life in the water. They are graceful and strong swimmers and can remain underwater for 3 to 8 minutes. Their bodies are streamlined, and their legs are short and they have webbed feet with claws. Their tails are long and tapered and help propel them through the water.

They have oily, dense fur and many layers of body fat that insulate them in the water. They are able to close their ears and nose when they submerge. They can move rapidly through the water and are very flexible.

The river otters facial whiskers are sensitive to touch and they have a keen sense of smell. Males and females are very similar in appearance, however the males are larger. They are both dark brown with light brown or grey underbellies. Their throat and muzzle tend to be silvery.

River otters travel on land with a funny, loping gait and in snow or ice they also slide.

These mammals are similar the the American Mink also found in Missouri, however they are quite a bit larger at 35-53 inches in length and 10-30 lbs in weight.

As mentioned, these otters are found in lakes, rivers, streams and other large bodies of water surrounded by forest. They bur - row under rocky ledges, large tree roots or stumps, under fallen trees or in thickets. They tend to utilize the former homes of beavers, woodchucks or muskrats.

These water mammals eat a lot of crayfish for most of the year, but when it gets colder in the winter they feed primarily on fish. They will also eat frogs, snakes, turtles, mussels, small animals and aquatic insects. The highly sensitive whiskers are used to find food underwater. They have a very high metabolism, so they eat frequently.

Otters are mostly nocturnal and remain active all year. They do not hibernate. They are far more social than the American Mink, choosing to live in family groups. They vocalize to each other with whistles, yelps, and screams as well as through body posture and touch. They also scent mark using their musk glands.

The females give birth to 2-5 young in February or March. The young will nurse until they are approximately 4 months of age, but they will stay in the family group until the next spring. River Otters tend to live a long life and in captivity have lived to 19 years of age.

If you are having trouble with critters on your dock, I recommend leaving a small transistor radio on at all times. We use this tactic and rarely have any signs of otter visitation.

Through research it is suggested that the otters have a minimal impact on the fish populations in large bodies of water, but may impact small streams and ponds.

Knowing that they communicate through droppings and secretions from their musk glands, it is best to remove any feces and traces of the otters as quickly as possible.

For Otter Control information please visit https://mdc.mo.gov/wildlife/nuisance-problem-species/otter-control

References:

1. https://mdc.mo.gov/discover-nature/ field-guide/north-american-river-otter

2. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/ north-american-river-otter