Photo courtesy of Maryland Department of Natural Resources/David Rivas

Party Animals

Tracking the Chesapeake’s Elusive Otter

The first time I ever saw an otter in real life, it scared me so much I almost fell out of my kayak. It was a summer morning on Morgan Creek, off the Chester River, and I had gone out for an early paddle before it got too hot. I had my camera around my neck, and I’d stopped to take a few shots of blue damselflies on stalks of pickerelweed. Just beside my kayak, a huge brown head silently emerged from the creek. I struggled to identify this annoyed-looking creature. Muskrat? No. Beaver? No. Otter? Yes! 

The otter and I looked at each other, almost eye to eye. This was no sweet little YouTube otter, juggling clams or cuddling pups. This otter was a bruiser. It could have easily chased my dog off its food bowl. “Chuff! Chuff!” The otter loudly told me off and I briefly feared for my life. We regarded one another for a while, then it turned and plunged back into the water. I sat for a minute with my mouth hanging open, frozen, until my heart started beating again. Finally I gathered my wits and paddled away, amazed, startled, and totally hoping to see it again.

Otter encounters like this are rare in the Chesapeake—so rare that avid boaters and kayakers can go a lifetime without seeing an otter in the wild. Otters are nocturnal and notoriously reclusive, preferring nighttime for socializing and hunting. Though they might build a den in a relatively populous human area, they often go undetected. 

While glimpses of otters are rare, the North American river otter (Lontra canadensis) is not. A semiaquatic member of the weasel family, otters are social creatures that can weigh up to 30 pounds, burrow in the soft soil along waterways, and prey on fish, frogs and clams. Today listed as a species “of least concern,” otter populations have recovered since the 17th and 18th centuries, when they were trapped to meet the European demand for otter fur. 

Otters are so charismatic and cute, people are naturally interested in them.
Photo by Matthew Fryer

A 1696 ledger in the Maryland State Archives shows that otter furs were used as a kind of barter currency. Otter furs, along with mink, raccoon, wolf, bear, muskrat and deer pelts, were valued at three pence per skin levied against taxes in the “Patuxent District.” Thankfully, the craze for American fur dwindled in the late 19th century as it fell out of fashion. Since then, otter populations have been largely left to their own devices. Yet, in the passing centuries, very little information on them has been gathered at all beyond the occasional glimpse. 

Dr. Katrina Lohan at the Smithsonian Environmental Research Center (SERC) in Edgewater, Maryland is hoping to change that. A specialist in marine disease and parasite ecology, her research has recently taken an unexpected turn toward otters. A colleague in the education department at SERC had observed some strange droppings on a waterfront dock. “It looked more like a splat than a log,” Lohan explains. “When she got closer, she realized it was full of fish scales and live worms. That’s when she called me.”

With the help of a trail cam, Lohan and her colleague discovered that a group of otters had been visiting the dock regularly, eating fish, playing, and, well, pooping. “We started calling them ‘poop parties.’ It was very much social behavior. The otters would gather on the dock, wrestle and eat, and then do these little dances,” says Lohan. “Pooping was part of their communication and socialization.”

As an expert in parasite ecology, Lohan is no stranger to scat. To get to the parasites, you need to go to the source. But typically, she explained, most species isolate the places where they eat from the places where they defecate. Otters, however, poop in the same communal spot on shore where they feed and socialize as well. These spots are called “latrines.” 

“Part of the reason I’m so excited about them is that otters break all the rules when it comes to parasite transmission” she says. “Otters basically eat, mate and play in their bathrooms.”

This unique behavior results in a lot of parasites—and for Lohan, that means a lot of information about not only the otters, but also the fish they were eating and the health of the river in general. Otters are apex predators, and their scat carries zoonotic diseases that impact both wildlife and people. If otters become infected with parasites from a certain kind of fish, it’s possible for humans to get parasites from that kind of fish, too. By studying SERC’s river otters and looking at the DNA in their scat, Lohan and her team can learn about the other animals and parasites that live in the same watershed.

“It’s an easy way to learn what pathogens are present in our food sources,” Lohan explains. “We can test it for genetics to understand what was in that meal, and the prior meal of the meal.”

Lohan’s team found 11 otter latrines on the SERC property on the Rhode River south of Annapolis. As they collected data on otter scat and observed the animals’ behavior, Lohan started her own background research into otters. She quickly discovered how sparse the data was on Chesapeake otters. 

“We realized that there’s very little known on the biology and ecology of river otters in the Chesapeake Bay,” Lohan says. “They’ve been here a long time, but that’s basically all we know about them. There’s not a single scientific peer-reviewed paper on otter in the entire Chesapeake watershed.” 

Because of Lohan’s parasite research, she and her team were unintentionally gathering new information on otter behavior, too. They brought in more game cameras and teamed up with an animal behaviorist. 

As the study went through a new round of funding, the range of focus expanded beyond the SERC campus into broader waters across Maryland, including urban areas. But this presented a new challenge—how to find otters in these different waterways? “We don’t know much about their population structure, what they’re eating or what parasites or diseases are impacting them here,” Lohan says. “Once you find their latrines, you can learn so much about them, but the first question is ‘where do you go?’ So we created this citizen-science approach to focus our efforts, knowing that people in the watershed were monitoring otters on their own.”

Lohan’s first step was to reach out to different public entities and environmental groups—national, state and county parks and educational nonprofits—that had been tracking otters individually. What she turned up was surprising. Otters have been spotted in the Tidal Basin in Washington, D.C., and in the Anacostia River. They’ve been reported in Baltimore’s Inner Harbor, and some were even accused of eating $10,000 worth of prized koi in Maryland. The otter’s range, it seemed, was expanding. But as they returned to regional waterways, they were met with some fuzzy unfamiliarity.

“One of my favorite stories came from a biologist at the U.S. Department of Energy and Environment,” Lohan recalls. “The reason we knew otters were back in the District (of Columbia) is because someone brought in a carcass and said, ‘Oh my god, we just found the biggest rat I’ve seen in my life. What is that?’ It turned out to be the first otter spotted in D.C. in more than 40 years.” 

The greater public has been invited to get in on the otter party. Lohan and her team have put out a call for citizens to report otter activity and latrines. Guides are posted on SERC’s social media and website that identify distinctive signs of otter activity, like paw prints, tracks in marshes, scraped up soil, and of course, their splats of scat with a strong fishy smell. Otter spotters are encouraged to inspect docks and things that stick up out of the water, and to upload information about their location, including photos and video to the SERC website so the team can follow up. 

The response has been strong. Lohan found that a lot of people had been tracking otters on their own. Otter behavior continued to surprise the team. One citizen scientist reported (with photos) an otter latrine on a backyard picnic table. Reports have flowed in of otters on docks, otters in gardens, otters on boats. It helps, Lohan admits, that otters work quite nicely as a scientific mascot. 

“It’s been really exciting to see how much people are really interested in this and want to participate,” Lohan says. “Otters are so charismatic and cute, people are naturally interested in them. The energy around this project is palpable.”

Lohan laughs when asked how she feels about becoming known as the “otter lady.” “Well, normally people pull a face when I tell them I study parasites,” she says. “But then I say I study the parasites of otters, and it goes from ‘ewww’ to ‘oh!” 

To participate in SERC’s otter study and join in the part, click HERE or check out the SERC Facebook page for more information. The data from citizen scientists is currently being collected and quantified. Submit your otter sighting, and download a helpful field guide for tips on otter scat, tracks, path and activity identification.


Kate Livie is a Chesapeake writer, educator and historian. An Eastern Shore native and current faculty at Washington College’s Center for Environment and Society, Livie’s award-winning book, Chesapeake Oysters, was published in 2015.