The mighty mole

February 20, 2011 at 12:00a.m.

Nature’s soil-tillers have proven to be stronger than a machine

By Lynda V. MAPES

Seattle Times

SEATTLE

Dew sparkles on acres of lush lawn, velvety smooth and green. Except, of course, where molehills pock the perfection.

The telltale mark of just about any lawn, these are mountainous molehills indeed, the workings of Scapanus townsendii, or Townsend’s mole, the largest in North America, or Scapanus orarius, the Pacific mole, just a bit smaller.

They are busily on the move all year, nearly always underground, tunneling after earthworms, their favorite food.

But moles are just now entering their busiest period, what with their breeding season getting under way, and repairing winter damage to their tunnels.

Moles are just about everywhere.

The moist, soft soils of mild winter days are prime for digging. And when it comes to tunneling, moles are without peer, outperforming even behemoth tunnel boring machines.

“To my great surprise, the moles win, hands down,” writes Robert “Red” Robinson, senior vice president of Shannon & Wilson Inc., of Seattle. He was asked to compare the capabilities of moles and “moles,” as tunnel-boring machines are affectionately known in the underground construction industry.

He sized up a typical 4-ounce mole versus the 642-ton Emerald Mole, the tunneling machine that recently completed light-rail tunnels here.

It turns out that, pound-for-pound, the tiny mole is an astounding 336 times mightier than the behometh Emerald Mole.

“It’s all in the weight ratio of the two critters,” Robinson wrote. “Anyone for nuclear-enhanced 600-ton, 20-foot-diameter, flesh-and-blood moles?”

Not for nothing is a grouping of the industrious tunnelers called a labor of moles.

Writing in The Journal of Mammalogy in his 1936 article “An Ecological Study of the Mole,” A.V. Arlton reports moles can move a mass 32 times their own weight — equivalent to a 150-pound person lifting 4,800 pounds.

Moles are perfectly adapted to an enchanted world underground, where no wind blows, and no freeze or heat bedevils them. They raise their young in nests insulated with grass, and have more hemoglobin in their blood than other mammals, the better to cope with the low oxygen levels underground.

Their velvety fur slips through the soil, and they move easily as swimmers underground. Their special shoulders and rakelike claws enable a rotary thrust movement that shears soil from the ground as they dig.

And dig, and dig.

A single mole can make several mounds in an hour, shoving the spoils up and out of the way, using surface tunnels specifically for that purpose, as they repair and expand their solitary subterranean kingdoms.

Moles forage in their tunnels, too, patrolling in search of their favorite food: earthworms. But they are falsely maligned as marauders of bulbs. That is the work of squirrels.

All those mounds in a typical city lot are the work of just a few moles, with slightly overlapping home ranges.

But for all this do these indefatigable ecosystem engineers get any thanks, as they turn the soil for free?

Hardly.

The arsenal of traps, poisons and home remedies deployed against moles is fearsome, from harpoons to shotguns to mothballs, human hair, castor oil, bubble gum, broken glass — you name it, people have tried it.

When moles are most active, about 20 percent of the calls agent Dave Pehling takes at the Washington State University extension office in Everett, Wash., are from people exasperated by moles.

“There’s not really a lot we can tell them,” Pehling said. That’s because nothing really works for long to get rid of a mole, and if it does, another will just move in.

But then, Pehling said he has yet to try a wandlike device sold on the Internet, used to inject and ignite propane in the ground.

“Everything around you rises about 3 feet,” Pehling said, sounding a bit jazzed. “It’s looks like a pretty messy way to deal with moles in a lawn, but it actually looks like a pretty fun tool, too, like something boys and men would like.”