March/April 2017For Wildlife Watchers: Eastern Moleby Rob Simbeck
Let's call him Ed. He was our neighbor in the '90s and he was, to be sure, not a wildlife watcher. In his worldview, everything was out to raid his garden, ruin his lawn or kill him. Weeds were to be eradicated, and if what he used ran off and fouled waterways, well, that was the way it was. Every snake was a copperhead, deserving of death. This was a man with free time, set ways and plenty of patience, and all of that came together quite dramatically in the case of moles. Dissatisfied with the traps proffered by local retailers and home remedies like cayenne pepper and mothballs, he would tamp down the freshest tunnel in his yard, pull up a lawn chair and a .45, and wait silently. A window-rattling "blam!" let us know when one more mole had been reduced to airborne components.
Some of us, on the other hand, have never minded them. They may be the bane of those who like picture-perfect lawns and golf courses, but it would be difficult to overstate their importance to the soil, and picture-perfect is overrated.
"Moles," says Dr. Gregory Hartman, professor of biology at Georgia's Gordon State College, "provide soils and soil ecosystems with aeration, physical turnover, the movement and cycling of nutrients, and the dispersal of mycorrhizal fungi." The latter, in symbiotic relationship with plants, allow for increased absorption of water and nutrients.
Far more than soil benefits from the churning and tunneling. "Mole tunnel systems," adds Hartman, "are used as travel corridors and/or places of refuge by a variety of invertebrate animals and vertebrates including shrews, voles, snakes, lizards, salamanders, frogs and toads." That's a lot of benefit from an animal that is, in the case of the Eastern mole, just six inches long and weighs just three ounces.
The mole is a digging machine, perfectly suited to underground travel. It uses a swimming motion, its big, pink, outward-facing front feet, with toes tipped in sturdy claws, churning through dirt like mechanized coal-diggers, pushing dirt under and behind itself as it travels. Its relatively large foreleg, shoulder and breast bones anchor powerful muscles that drive those feet, enabling it to dig at 4.5 meters an hour, or an inch every fifteen seconds. It's got a sensitive, naked tail to help guide it in backing up, and velvety fur that can lie flat in either direction, so as not to impede motion.
You'd be hard-pressed to detect sense organs. The eyelids are fused over the tiny eyes, which are just sensitive enough to tell light from dark. Although moles have good hearing, their ears are hidden under their fur. The snout - long, relatively naked and pink - has sensory whiskers and nostrils that open upward.
Overall, moles look for the same things we do in soil. "Eastern moles," says Hartman, "seem to prefer sandy, loamy soils and avoid heavy clay soils." They're looking for abundant food, as constant digging is a high-energy operation. A mole will consume about half its weight per day, feeding on earthworms, slugs, snails, centipedes, cutworms, insects and their larvae (including undesirables like Japanese beetles), and occasionally some seeds. The surface tunnels we see are essentially dining runs, and they are just the upper chambers of an elaborate subway system. They are connected to a permanent set of passageways a foot or so underground providing habitation, relief from heat or cold (moles do not hibernate) and, in the spring, for a nest/nursery. Sometimes the central den will be under a tree, shrub, stump or rock - or, for that matter, a sidewalk or patio. In excavating those tunnels, the mole will pile dirt at above-ground locations above vertical shafts - your basic molehill.
"The dynamics of tunnel usage (surface or deep) really have not been studied very much," says Hartman. "We do know that one mole will use the abandoned tunnels of another, which makes sense when you consider the expenditure of energy required to construct a tunnel. One particular tunnel in South Carolina that I kept track of still was in use after ten years."
As moles dig, they secrete from oil glands a musky substance thought to discourage predators, mark territory and serve as a sexual signal. It also stains their fur, leaving brownish yellow patches.
In South Carolina, the Eastern mole is one of three species. The hairy-tail mole, says Hartman, "occurs in the more mountainous regions of the northwest part of the state where there are soils that are more rocky," and the star-nosed mole "tends to occur in moist habitats or soils near streams, Carolina bays, etc."
The Eastern mole's Linnaean name is worth notice here. Scalopus means "digging foot," and it's perfectly in order. Aquaticus means "found in water," and it shows Linnaeus didn't always hit it on the head. He found one dead in the water, took note of the webbed feet and erroneously assumed a connection.
Description: Large claws, silver-brown fur above, paler underneath. Six inches long, three ounces in weight, male slightly larger than female.
Range and Habitat: Native to eastern U.S. In good soil throughout South Carolina.
Reproduction: Forty-five day gestation. Born naked and blind.
Viewing Tips: Look for telltale surface tunnel ridges and/or mounds.
Being underground is an excellent defense mechanism, although they are above ground some of the time and some creatures will take the time to dig them up. They fall prey to owls and hawks, foxes and coyotes, cats and dogs, and, as someone who has raised chickens, I can tell you now and then a chicken will dig one up and kill it. Then, of course, there are snakes, which can follow them into their burrows. And this is a parasite magnet, with fleas, lice and mites all dogging them.
Moles have home ranges, averaging about two-anda- half acres for males and three-quarters of an acre for females, with wide variation depending on the quality of soil. In great dirt, you can find several per acre. The mating process gets underway in spring, when, says Hartman, "males enlarge their home ranges. Sometimes this involves extending tunnel systems, traveling above-ground, or both." Once he finds a female and mates, he will move on to find another. The female builds a spherical nest chamber lined with dry plant material. After a gestation of about forty-five days, she gives birth to three or four young, as early as March, in warm climates, and as late as June farther north.
New tunnel systems may soon appear where you are. Our former neighbor notwithstanding, we'd do well to appreciate them and cut them some slack. A great lawn looks as good to a mole as it does to you, and if you've got moles, it simply means you're doing good work.