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.