Making mole hills in the mountains
While bunnies, bears, mice and myriad other animals were main characters in my childhood storybooks, only the “Wind in the Willows” featured the lowly mole. That just fed my curiosity about this mysterious animal, so one day I followed a mole tunnel and dug up its engineer.
The creature looked like no other I’d encountered. It had eyes the size of a pin head; huge, shovel-like forefeet; a pointed, bare nose; a short, bare tail; and a fat, cylindrical body covered in soft gray fur. It was obviously built for a specific environment and looked woefully inadequate out of it.
Searching for “mole” online results mostly in exterminator listings. In an effort to control nature and keep it at bay, humans are prone to becoming obsessed with having tidy lawns and waging war on perceived threats to these ecological deserts, particularly moles. However, moles are not the great destroyers of lawn and garden many people think they are. “While moles may dislodge plants while looking for prey,” says the Virginia Cooperative Extension (VCE) website, “they destroy very few plants or bulbs by direct feeding.”
In fact, VCE points out, moles provide great benefits: “Moles are extremely beneficial because they consume the larvae and adults of numerous pest insects, such as Japanese beetles, that affect gar- den, landscape, and flowering plants.” And their tunneling activity “loosens the soil, improves aeration, and mixes deeper soils with surface organic material, all of which enhance soil quality.”
Other than an occasional mowing, my lawn up here on the mountain is left to its own devices. The result is a mix of the cold-season, nonnative grass that was planted to create the original lawn, “weeds” (all the other green stuff that just showed up on its own), rocks and bare patches. With this year’s warm winter, at least one mole has been taking advantage of this self-naturalizing landscape, digging a network of tunnels that extends throughout the yard and beyond.
Often thought to be rodents, moles are actually in the taxonomic order Insectivora, which also includes shrews and bats. Three species of this small (4–8 inches), near-blind mammal are native to Virginia. The eastern mole (Scalopus aquaticus), the species I dug up as a kid, is found statewide. The hairy-tailed mole (Parascalops breweri), similar to the eastern mole, keeps to the higher elevations of the Appalachian Mountain region. The star-nosed mole (Condylura cristata) prefers wetlands in the Coastal Plain, the northern Piedmont, and the Shenandoah and New River valleys.
While all moles may look strange to us humans, the starnosed is like something out of science-fiction. The Mother Nature Network website included it in its list of “13 of the Ugliest Animals on the Planet.” This dubious distinction, as well as the mole’s common name, can be attributed to the 22 short, fleshy appendages (“tentacles”) surrounding its nostrils. According to VCE, this is the only mammal with such an adaptation.
From a biological perspective, these tentacles are far from grotesque. As a PBS Nature episode about this species, “The Beauty of Ugly,” reveals, the tentacles carry 25,000 sensory receptors that, like those in the whiskers of many nocturnal predators, help provide information about the surrounding environment. The tentacles enable the mole – despite its sight deficiencies – to be incredibly efficient in finding prey, even in its murky marshland habit. Biologist Kenneth Catania of Vanderbilt University, whose research is featured in the episode, found that the star-nosed mole is “operating at, or near, the limit set by the speed which the mole’s nervous system can process touch information.”
As Catania discovered, the mole also compensates for its limited sense of smell by blowing bubbles under water that are aimed at specific targets, then immediately sucking the bubbles back into its nose. Apparently, the bubbles carry the smell of what they bounce off of, alerting the mole to potential prey. This surprised scientists, since mammals were not thought to be able to smell underwater at all, let alone do it through this technique.
Mole tunnels vary by species. The star-nosed moles dig deep – rather than long – tunnels, leaving volcano-shaped hills as wide as 12 inches. Eastern and hairy-tailed moles burrow close to the surface, forming long ridges near the soil surface that we typically associate with moles. These shallow tunnels are connected to deeper ones, where the moles can take shelter from cold weather, follow prey and hide from predators.
Moles work day and night year round, digging up to 150 feet of tunnels per day, according to VCE. To replenish the enormous amount of energy expended, they consume 70 to 100 percent of their body weight daily, eating pretty much any small animals they come across, including insects, earthworms, snails, slugs, other small invertebrates and even baby mice and birds. Adapted to its wetland habitat, the star-nosed mole is a good swimmer and also hunts in the water for mollusks, crustaceans and small fish.
Moles are in turn consumed by a variety of predators that can get past the unpalatable musk moles can release in defense. These include raccoons, skunks, foxes, weasels, snakes, hawks and owls, coyotes, and domestic dogs and cats. I got my first dog when I was six, and he was a mole fiend. In his eagerness to dig them up, he disrupted our yard far more than his prey did.