Every time I take questions during a garden lecture, there’s always someone in the audience who tells me that moles are eating their bulbs and plants! And I always answer that moles are total carnivores and are interested only in meat. But moles use their tunnels only once before bequeathing them to voles (which resemble the children’s book character Danny Meadow Mouse). And voles are dedicated vegetarians, interested only in potatoes, roots or other vegetation.
There are three species of moles: the eastern (or common), the hairy-tailed and the star-nosed mole. Moles generally eat earthworms, grubs and other invertebrates; the hairy-tailed mole can consume three times its own weight in 24 hours.
But the star-nosed mole is unique among mammals. Its name derives from a ring of 22 fleshy, pink tentacles at the end of its nose that move as the animal searches for food. Generally at home close to water (we have them because we live at the edge of a lake), they can actually dive and swim.
According to research published in the journal Nature, the star-nosed mole can detect small prey and devour it faster than the human eye can follow. It takes a driver about 650 milliseconds to hit the brake after seeing a traffic light turn red; but the tiny, furry mole can detect a grub, decide it’s edible and gulp it down in a fraction of that time!
The mole’s secret is that same star-shaped appendage. Because these animals literally work in the dark, they have very poor eyesight. But they continually monitor the world around them by touching everything with that star. And the researchers found that after touching a small piece of food, these moles took a mere 230 milliseconds, on average, to identify it as edible and chow down.
In this, the mole is also aided by its unusual teeth — very small incisors that are formed like miniature tweezers, allowing the mole to grasp small prey with great delicacy.
“It’s more difficult,” says Nature, “to subsist on a diet of small animals than it is to live on larger prey. For example, it is more efficient to kill a 1,000-pound beef cow for food than 125 eight-pound rabbits. That’s because it takes substantially more time and energy to kill and consume the rabbits. Ecologists have formalized this relationship with a factor called prey profitability. By reducing its handling time to a fraction of a second, the star-nosed mole may be able to achieve a net energy ‘profit’ with a diet of insect larvae and other food sources. Of course, that doesn’t mean it turns up its nose at larger prey, like long, luscious earthworms.”
This fascinating research was supported by a grant from the National Science Foundation, and here is money well spent! I, for one, will look at the star-nosed moles in my back yard with renewed respect.
[Peter Loewer, aka The Wild Gardener, is a regular contributor to Xpress.]