River Otters: Hardest-Working Clowns in the Water

Otter standing in tall grass

 Jaymi Heimbuch

Playful, curious, rambunctious and so much fun to watch, North American river otters are an important part of a healthy riparian habitat. River otters can be found near lakes, rivers, swamps and estuaries. Click through to see more photos of these adorable animals and learn more about just how amazing they are.

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Social Creatures

Jaymi Heimbuch.

River otters are social animals, living in family groups that usually consist of a mother and her offspring, possibly including "helpers" who are offspring from previous years or even unrelated adults. Adult males will also form social groups. Here, a family of four sit on a beach just before dawn in a session of mutual grooming before jumping back in the water to fish.

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Breakfast Time

Jaymi Heimbuch.

Bonded social groups of river otters will hunt together, such as this group of three that are catching and feeding on small fish and crustaceans for breakfast. The river otters also use the same dens and resting sites, and will even leave scat in the same location.

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Long and Sleek

Jaymi Heimbuch.

North American river otters are not to be mistaken for sea otters, which (among other differences) live exclusively in the ocean. Nor should they be mistaken for beavers. You can tell a river otter by its long, sleek body, webbed and clawed feet, and a long muscular tail that is slightly flattened and tapers toward the end. They are long like their weasel cousins, and have an adorably large black nose.

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Water or Land? Doesn't Matter

Jaymi Heimbuch.

Though brilliant swimmers, river otters are as comfortable on land as they are in the water. They can walk and run easily on land, even in vegetation, and are known to slide on slippery surfaces like ice and mud as a speedy, easy way of getting from one place to another. Over land and water, they can travel as much as 26 miles in a single day when necessary, though they more often travel only a couple miles in one day.

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Nothing Like a Cozy Den

Jaymi Heimbuch.

River otters build dens close to the water line, with multiple tunnels. Here, a river otter gathers reeds that it takes to an underwater entrance to a den site. Nothing like a pile of fresh reeds to make a soft, comfortable bed.

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Predator and Prey

Jaymi Heimbuch.

Fast, agile swimmers with powerful jaws and sharp teeth, river otters have few natural predators when they are in the water. On land, however, they must be wary of predators such as bobcats, coyotes, mountain lions, wolves, black bears and foxes. Even domestic dogs pose a threat to the river otter when on land.

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The Human Threat

Jaymi Heimbuch.

However, the biggest threat to river otters is humans. River otter fatalities occur through trapping, shooting, being hit by cars, and being accidentally caught in fishing nets or fishing lines. River otters have been virtually eliminated from some areas due to these causes as well as habitat destruction and pollution. The species is highly sensitive to pollution, and its disappearance from an area is an early indicator that things are not well with the habitat's health.

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Conservation and Sutro Sam

Jaymi Heimbuch.

Conservation projects to bring river otters back to their natural habitats have proven to be successful. One river otter that made headlines in San Francisco proved just how exciting it can be when river otters reappear. This is a photo of Sutro Sam hanging out on the seawall at the ruins of Sutro Baths. The now-famous river otter temporarily made his home in the pond and was the first river otter to be spotted this far south in the bay area in 30 years. His appearance is a sign that significant conservation efforts to improve riparian habitats over the years are indeed working.

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Where Did Everybody Go?

Jaymi Heimbuch.

An examination of river otter populations in 1980 showed that the species had been wiped out in 11 states, and had drastic declines in nine more. However, conservation had started four years earlier, in 1976, after many had already noticed the severely dwindling numbers and began programs for reintroducing otters into former habitat.

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Trapped for Their Pelts

Jaymi Heimbuch.

River otters are still trapped for their luxurious pelts, but with an eye toward long-term conservation. While the annual harvesting does not impact existing populations, it is possible that it does slow or stop the expansion of populations into former habitat that no longer has river otters. Another issue that slows or stops expansion of otter populations is water pollution and habitat destruction.

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Good Swimmers, Long Whiskers

Jaymi Heimbuch.

River otters, as we know, are amazing swimmers. They can stay under water for almost four minutes, and swim at nearly 7 miles per hour. In one dive, a river otter can travel more than 400 yards! They use their long vibrissae, or whiskers, to sense where fish and other prey are located, as well as their sharp hearing and sense of smell.

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Bone-Crushing Teeth

Jaymi Heimbuch.

Once prey is caught, river otters use their powerful jaws and sharp teeth to make short work of their meal, even crustaceans. They have canines that deliver a lethal bite, and molars that can crush bones and the shells of mollusks.

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Go Ahead, See for Yourself

Jaymi Heimbuch.

If you'd like to see a river otter for yourself, check out sightings in your local area, or perhaps visit a zoo. While mostly absent from the Midwest and Southwest United States, you can see them in the wild in the northern, eastern and southeastern areas of the country, as well as throughout Canada.

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Be an Otter Spotter

Jaymi Heimbuch.

If you live in the Bay Area of California and happen to see a river otter, report your sighting to the River Otter Ecology Project, a citizen science program that relies on "otter spotters" to help learn more about the locations, behaviors and health of local river otters. Meanwhile, many conservation programs are working to restore river otter populations to areas where they have disappeared, including the Southwest.