When hiking in the mountains, you’re often reminded to stick to the trails to protect alpine plants. But it’s not just diapensia or dwarf cinquefoil that’s eking out an existence in these high elevations. The rare northern bog lemming also calls some of our alpine environment home.
This small mammal weighs just an ounce and has a brown and gray coat, a blunt nose, and a short tail. More common in Canada, where it lives in lower, tundralike habitats, it has been recorded in five locations in Maine, including two sites in Baxter State Park. It has also been spotted in three places in New Hampshire: along the Wild River, near the base of Mount Washington, and on Mount Moosilauke.
MOSSY AND DAMP
As its name suggests, the northern bog lemming is usually found in moist meadows or boggy areas, often near a source of water. It is so fond of sphagnum moss—a staple of its diet, along with sedges, grasses, fungus, and raspberry seeds—that its droppings are bright green. “Green poop is one indicator that a bog lemming is around,” says Charlie Todd, the endangered and threatened species coordinator for the Maine Department of Inland Fisheries and Wildlife.
Other indicators include the “runways” that northern bog lemmings make above ground or below leaf litter. They create these paths by tramping down the grass or clipping it with their teeth. But don’t expect to see the animals themselves. They’re elusive creatures that nest underground and hide in vegetation.
The northern bog lemming seems to have been pushed to the mountains from other ecosystems. “They’re there somewhat by default because they don’t have to compete with meadow voles or southern bog lemmings, which are more successful lower down,” Todd says.
The northern bog lemming is listed as “threatened” in Maine due to its rarity. Although no specific conservation plans are in place to protect the species, state officials are keeping an eye on a wind power project near one site where the animals are known to live and are consulting on other developments that might affect the lemming’s habitat.
Beyond the human-scale encroachments of climate change, ski areas, logging, and wind turbines, northern bog lemmings face the usual challenges of creatures their size: threats from predators such as hawks and owls, and competition from other small mammals.
To understand where northern bog lemmings live and how many there are, researchers have traditionally looked for signs including green pellets and grazed runways. But these methods cannot distinguish between the rare northern bog lemming and its more common southern cousin. To make that distinction, scientists traditionally have had to capture and handle the lemmings.
Zach Olson, an assistant professor of animal behavior at the University of New England in Biddeford, Maine, is developing a new method. He plans to test the DNA of the lemmings’ green pellets to distinguish whether they came from northern or southern bog lemmings.
“There’s a whole lot we don’t know,” Todd says. “This kind of CSI for wildlife can help us learn where they are, which is a first step to protecting them.”