Playful North American river otters often sound like squeaky toys as they wrestle each other, slide down riverbanks or frolic in water. Spotting these cute, furry animals is not only good fun, it’s also good news for the environment.

North American river otters are a species whose population can indicate how healthy (or not) the environment is. The otters experienced a steep drop in numbers in the 1900s because of fur trapping and pollution, but they are not considered endangered today. The nomadic animals often travel miles over land or through rivers and streams, seeking habitats with clean water and a healthy fish population.

High on the food chain, river otters eat fish, clams, snakes, turtles, small mammals and birds, so researchers look for contaminants and parasites in otter spraint, or poop, to learn about the health of the surrounding environment and its food sources.

Otters' funny dance

River otters don’t need music to do a funny rhythmic two-step with their short hind legs, while raising their long tails and wiggling their butts as they defecate. This funny motion, known as “the poop dance,” releases spraint that serves as an ID card — like a “who’s who” among otters.

Spraint is one of the things scientists look for to track the presence of otters.

Karen Sheffield, manager of Huntley Meadows Park, south of Alexandria, notes that while otter sightings are unpredictable, recent tracks and spraints show there has been increased otter activity there. A wetlands restoration project finished six years ago at the park is minimizing invasive species, making way for healthy native ones.

The Elizabeth River, a key Chesapeake Bay tributary flowing between Norfolk and Portsmouth, Virginia, was long considered a “dead river” because of toxins. It’s now flourishing after a decade of community efforts to keep out chemicals and waste.

“In the past five years, we have seen a great many more otters,” said Marjorie Mayfield Jackson, director of the Elizabeth River Project. “It means we are doing our job in the community and for the otters.”

Conservation 'ambassadors'

Nonprofit organizations are raising awareness of river otters’ importance.

The Elizabeth River Project helped develop an otter display at Nauticus science center in nearby Norfolk. Wild otters are often seen hanging around the docks there. An “Otter Spotter” program encourages volunteers within the river’s watershed to document any other sightings or signs of activity.

A newly formed Smithsonian Institution project is looking for people — including kids — to help scientists learn more about the animals.

“No one has ever done scientific research on otters in the Chesapeake Bay area,” said Karen McDonald of the Chesapeake Bay Otter Alliance. The alliance is the Smithsonian’s citizen-science project designed to help people understand otters and their important role in the food web. Anyone can email sightings of river otters or their spraints.

And everyone can help provide a good home for the otters.

“Otters need a clean watershed to live,” McDonald said. “We are all watershed neighbors, and we need to be good neighbors.”

Learn more

Find out about river otter spraint and the broad range of information found within, plus see a video of a poop dance, at

The Maryland Zoo and the Smithsonian’s National Zoo have river otters. When you have a chance, watch them in action. Check opening hours online.

The Potomac Conservancy offers more river otter fun facts at

Get involved with otter research. If you’ve seen river otters or evidence of them in the Chesapeake Bay watershed, you can help. Visit the Chesapeake Bay Otter Alliance at