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In the rivers of West Virginia, a charismatic native returns—and researchers are leading the charge to ensure it stays.
This story was originally published in the June 2025 issue of Wonderful West Virginia. To subscribe, visit wonderfulwv.com.
Written by Mikenna Pierotti
It’s not hard to spot them when you know what to look for. You might catch a blur of soft brown fur slipping beneath the surface of a stream. You might hear their sharp whistles echoing off a rocky riverbend. You might even see them in a boisterous group—aptly called a “romp”—playing and tumbling over each other like toddlers.
But it wasn’t always this way. By the 1950s, the North American river otter, Lontra canadensis, a species once widespread throughout the state’s waterways, had vanished from West Virginia entirely.
“Unregulated trapping and widespread habitat degradation led to their extirpation—that is, locally extinct,” explains Holly Morris, furbearer and small-game project leader for the West Virginia Division of Natural Resources (WVDNR). Otters, with their luxurious pelts, were once the jewel of the American fur trade. But few regulations and an ever-shrinking habitat meant populations couldn’t sustain themselves.
That all changed in 1984, when a bold reintroduction effort began to restore the otter to its rightful place in our ecosystem. Initiated by WVDNR, the WV River Otter Research Group was recently developed at WVU, having included genetic, diet, and survival studies. But before diving into the science behind their comeback, it’s worth understanding what makes these elusive mammals so unique—and why their presence in the water means so much more than meets the eye.
Cute and Cunning
Sleek, agile, and undeniably charismatic, the North American river otter is one of West Virginia’s most captivating native species. Built for life in and around water, these mammals are equipped with webbed feet, streamlined bodies, and thick, waterproof fur that traps insulating air to keep their skin warm and dry—even during long underwater hunts. Their strong jaws and sharp teeth may be hidden behind playful expressions, but make no mistake: otters are deadly predators.
Primarily carnivorous, river otters feed on a variety of aquatic prey, including fish, crayfish, frogs, turtles, mussels, and even the occasional small mammal or bird. Opportunistic by nature, they adapt their diet to the season and the local ecosystem.
Otters are also known for their social flexibility. While typically loners—especially adult males—they sometimes form temporary groups during times of abundance. These roaming bands are often made up of young males who join forces to hunt in fish-rich waters, only to part ways once the food supply dwindles. Moms, on the other hand, remain with their pups for up to a year, teaching them all of the survival arts.
In captivity, river otters display a different facet of their nature—social behaviors like cuddling and cooperative play—that’s seen less frequently in the wild. These interactions, especially in colder months, serve both to maintain group bonds and regulate body temperature.
Despite their charm, river otters are elusive in the wild. They’re most active during dawn and dusk, and their sensitivity to human presence means they often slip away unnoticed. But if you do spot one—slipping down a muddy bank or churning up the shallows—it’s a moment you’ll never forget. Their presence is not just a rare delight for wildlife lovers but also an important bellwether for the health of the ecosystem around them.
The Revival
That’s just one reason why, between 1984 and 1997, WVDNR biologists undertook a bold and ambitious plan: to bring these charmers back. Over those 13 years, 248 otters were reintroduced from across the eastern U.S.—including Louisiana, Maryland, North Carolina, and South Carolina.
“We monitored populations for years through harvest surveys, bridge surveys, and population modeling,” Morris says. “Eventually, we deemed the project a success.” In 2011, West Virginia officially reopened a recreational trapping season, with a cautious bag limit of one otter per year.
But as the 40-year anniversary of the reintroduction program approaches, the question remains: How well is the population really doing? Can we safely increase harvest limits? Are otters thriving in every corner of the state? And what can these sleek, playful mammals tell us about the health of our waters? That’s where the West Virginia River Otter Research Group comes in.
“River otters are apex predators,” Morris says. “And humans are really their only predator.” That makes them ideal indicators of ecosystem health. When the rivers are clean and full of fish and crayfish, otters are there. When pollution and degradation take hold, they disappear. “The presence of otters tells us a river is thriving,” she says. “Their return is a sign that environmental regulations put in place since the 1970s are working.”
Traps, Tags, and High-Tech Tails
To understand otter survival rates—and whether changes to harvest regulations are warranted—WVDNR researchers began capturing and tracking otters using a mix of high-tech tools and old-fashioned fieldwork.
Otters were caught using box traps and foothold traps, placed in areas known for otter activity. “These traps are designed to hold the otter safely and humanely,” Morris notes. Once captured, otters were transported in well-ventilated PVC tubes—a calming, secure way to move them with minimal stress—to licensed veterinarians.
At the vet, each otter underwent a quick procedure. “They were chemically immobilized so we could collect basic data like sex and body size, then apply ear tags for identification,” Morris explains. But the real innovation came next.
“We placed two types of transmitters on the otters,” she says. “One was an internal VHF transmitter, surgically implanted in the abdomen. The other was a new external GPS transmitter, attached to their backs.”
West Virginia is the first state to use GPS tracking on river otters. “This GPS unit collected location data every 30 minutes,” she says. “We saw males travel over 15 miles in a single night and maintain home ranges as large as 30 miles.”
From this study, researchers are collecting a treasure trove of information on everything from survival and harvest rates to habitat use and movement patterns to population growth rates.
When an otter died, the team tracked the signal and recovered the carcass to determine cause of death—critical for modeling survival trends. Otters are also monitored through a long-standing program where carcasses, usually roadkill or legally harvested individuals, are collected, aged via tooth analysis, and studied for reproductive data. “These carcasses support additional projects, too,” Morris adds, “like diet studies, toxicology, and now, DNA research.”
That second arm of the project—using DNA to learn more about otters’ diets and genetics—will be vital for the future of the entire species. Through DNA metabarcoding, researchers analyzed stomach contents from 100 otters to learn what they eat. The findings? Despite the fears of anglers, “Sunfishes and crayfish were the most common items,” Morris says. “Only nine otters had eaten trout, and four of those were collected under nuisance permits. It shows otters don’t rely on trout as a primary food source.”
DNA analysis also shed light on the population’s health. By comparing DNA from otters in West Virginia, neighboring states, and the original source states, researchers confirmed that the reintroduction program succeeded. “We have a genetically healthy otter population,” Morris says proudly.
Even more exciting. The GPS tracking method developed here could be adopted nationwide, giving biologists from other states a template for managing their own river otter populations.
Science for Everyone
Public participation is vital to this process. “People can help by donating carcasses or participating in the annual trapper survey on our website,” Morris says. “And more research is always on the horizon.”
She’s excited about what’s ahead. “This is cutting-edge work. The data we’re collecting is the first of its kind in West Virginia since the 2011 trapping season began. It’s going to reshape how we understand otters in this state—and help us protect them for the future.”
The annual trapper survey, as well as other citizen science opportunities, can be found when you visit WVdnr.gov/plants-animals/surveys.
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