From: New York Times
The question of how moles move all that dirt when they tunnel just under the surface of lawns has never attracted the extensive study that other forms of locomotion — like the flight of birds and insects, or even the jet-propulsion of jellyfish — have.
But scientists at the University of Massachusetts and Brown University have recently been asking exactly how, and how hard, moles dig.
Yi-Fen Lin, a graduate student at the University of Massachusetts, reported at a recent meeting of the Society for Integrative and Comparative Biology that moles seem to swim through the earth, and that the stroke they use allows them to pack a lot of power behind their shovel-like paws.
Ms. Lin measured the power of hairy-tailed moles that she captured in Massachusetts and found they could exert a force up to 40 times their body weight.
She also analyzed and presented X-ray videos taken of moles in a laboratory enclosure tunneling their way through a material chosen for its consistency and uniform particle size: cous cous.
Angela M. Horner recorded the videos while studying the movement of Eastern moles in the lab of Thomas Roberts, a professor at Brown.
One reason moles have not been studied as much as some other animals may be that they are not easy to capture or keep in a laboratory.
“People said, ‘You won’t be able to catch them and you won’t be able to keep them alive,’ ” said Elizabeth R. Dumont, an evolutionary biologist who is Ms. Lin’s dissertation adviser.
Ms. Lin solved the first problem by camping out in mole territory, on golf courses and farms, and marking their tunnels with sticks that she would watch for hours until movement indicated a mole on the move.
She would then run ahead and block the tunnel by sticking a shovel in the ground, and go behind the mole and use another shovel to dig the animal out.
As for maintaining the creatures, their high metabolism was the problem. They need to eat their body weight in food every day or they can die quickly.
The diet that satisfied their energy needs, Dr. Dumont said, included earthworms, mealworms, eggs and sunflower seeds. It worked so well, she said, “we had to put a couple of them on a diet.”