Appalachia's wild rat is mysteriously disappearing—but the pandemic offered hope

Grantsville, Maryland — On a foggy morning, high in the Allegheny Mountains of western Maryland, ecologist Dan Feller cradles a furry rat in his hands, poised to set it free. “Get your camera ready,” he says. “Though. it will probably come back and stare at us,” he adds with a shrug.

The brownish-gray animal quickly leaps upon a rock and disappears. Then, just as Feller predicted, it pops back up on an outcrop a few feet away, watching us calmly. This behavior is remarkable, considering Feller had humanely trapped the animal and tattooed its ear only minutes ago. 

The Allegheny woodrat, native to the Appalachian Mountains and parts of the Midwest, is not your average rodent. The species is innately curious and docile around people, a unique trait not found in most other mammals of the eastern U.S.

“They’re so charismatic and easygoing,” says Gretchen Fowles, biologist for New Jersey’s Endangered and Nongame Species Program. When found in a research trap, they’re usually found sitting calmly and quietly, she says, seemingly unperturbed.

The one-pound, hairy-tailed rat is notable for another reason: its population is in a swift and mysterious decline. Listed as endangered or threatened in much of its range, especially in the north, the species is locally extinct in New York, Connecticut, and Massachusetts. Pennsylvania has lost 75 percent of its woodrat population in just four decades, and just one population remains in New Jersey and Ohio.

Maryland has lost more than 65 percent of its woodrat population since the 1990s, something Feller, of the Maryland Department of Natural Resources, has observed firsthand. Over the past three decades he’s trapped hundreds of woodrats, but now he is lucky to catch a dozen in a single year, amounting to what he calls a disturbing trend.

Scientists don’t know why the large-eyed species—which uses its long, sensitive whiskers to navigate through their homes in dark caves and caverns—is disappearing. It’s likely a combination of factors, including the American chestnut blight in the 1900s, which wiped out a primary food source; and a fast-spreading parasite, Baylisacaris procyonis, colloquially known as raccoon roundworm. (See a satellite view of how eastern U.S. forests have disappeared.)

Because of this uncertainty, and the several states involved, it’s been tough to bring together people working on Alleghany woodrat conservation, Feller says.

But in 2020, the pandemic changed all that: After a regional conference was canceled, mammalogists from 13 states began to meet monthly on Zoom, sharing data and strategies for restoring the rodent’s population.

This unified approach has energized woodrat conservation, Feller says, in particular now that state biologists have connected, they can more easily partner together to apply for larger grants.

“Many people may not know these woodrats even exist, but that doesn’t mean they’re not worth saving,” he says. “Their existence is part of what makes these mountains so special. They’ve long been a part of our eastern forests, and they should be for future generations.”

The curious habits of pack rats

Of the 12 woodrat species in the U.S., the Allegheny is one of the largest and rarest. Unlike other rodents, it’s not a bountiful breeder; females produce an average of two pups a litter, only about two or three times a year. 

These animals prefer higher elevations, scampering through caves, cliffs, and rocky outcrops along mountain ridges. Woodrats are important to their ecosystem because they disperse seeds and provide food for many larger animals, such as bobcats, coyote, owls, and snakes. (Read how Norwegian rats can remember who’s nice to them—and return the favor.)

While woodrats live a mostly solitary existence, defending their territories, many live in colonies in close proximity to one another.

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As member of the pack rat family, Alleghany woodrats are collectors, harvesting natural material for their nests. Beyond shredded bark and other organics, these materials can include human objects, such as candy wrappers, fine china, and—in at least one instance, according to Feller—a headless Barbie doll. No one is sure why the animals collect human artifacts, but it is most likely due to their curious nature.

A series of threats to woodrats

Before the American chestnut blight wiped out most of that species over a century ago, woodrats dined on the trees’ plentiful mast, or fruit.

With chestnuts gone, the animals then turned to oak acorns, storing them in caches over the winter. But invasive gypsy moths have damaged many oak forests in recent decades, further reducing the woodrats’ food supply, Feller says. Deforestation and fragmentation throughout the eastern U.S. have also likely driven down their numbers.

Now particularly concerning to experts is raccoon roundworm, a fatal parasite whose primary host is raccoons, a species expanding into woodrat habitat. The rodents contract roundworm while gathering seeds in raccoon feces; the worm larvae attacks tissue in their eyes and brain, leading to blindness, neurological impairments, and eventually death. 

Solutions to save the species

Thanks to the new woodrat working group, solutions are emerging.

Scientists in Pennsylvania, who have been monitoring the threatened woodrat population via camera traps, shared their technique with other states, such as North Carolina, where the species is listed as of special concern.

A project launched in 2020 to survey woodrat colony sites is a direct result of this new collaboration, says Andrea Shipley, mammalogist for the North Carolina Wildlife Resources Commission.

“We wouldn’t have been as successful last summer without their detailed guidance,” Shipley says.

More consistent population data from the working group will give states a better idea of how many woodrats exist, and further inform conservation plans, says Howard Whidden, a small mammal and conservation biologist at Pennsylvania’s East Stoudsburg University.

“You have to take a multifaceted approach with Allegheny woodrat” conservation, Whidden says. Trapping raccoons to test them for roundworm and translocating woodrats from one location to another are two such approaches.

Ohio, Pennsylvania, and New Jersey are now exchanging rats between states, releasing them into the wild in an effort to boost genetic diversity among the isolated woodrat populations. (Read about giant rats that help sniff out landmines.)

The working group is also appealing to eastern U.S. zoos, encouraging them to breed Allegheny woodrats in captivity, which could increase their numbers in the wild. 

Other potential interventions include establishing mast feeding stations to supplement woodrats’ diet, replanting blight-resistant American chestnut trees, and even using drones to drop anti-parasitic fishmeal into woodrat habitat to treat roundworm-infected raccoons. 

Back in the Alleghenies, surrounded by mountain laurel thickets and blooming great rhododendron, ecologist Feller places the woodrat trap into his backpack and we begin our hike back down the mountain, leaving the forest to the rats.

“They sure are cool, aren’t they?” he says as the inquisitive woodrat watches us walk away, still perched on the rock.