Crawling on water

Snails have amazing mucus-superpowers! Most snails and slugs use mucus trails to lubricate their movement, but some freshwater snails have taken slime to the next level. They can actually crawl along on the underside of the water’s surface. How can a wee little snail foot grip something so nebulous?

Science reports on new research on just how the snails are able to move on a low-friction flexible surface. They explain:

The snail’s foot wrinkles into little rippling waves with a wavelength of about a millimetre and this produces corresponding waves in the mucus layer that it secretes between the foot and the air. But because surface tension constrains the deformation of the mucus, the shape of its top surface (in contact with air) doesn’t exactly mirror that of the bottom surface (in contact with the foot). In effect, parts of the mucus film get squeezed, and parts get stretched, creating a pressure difference that pushes the foot forwards.

The snails are not actually gripping the water – they’ve got little bubbles of air in their shells for buoyancy. They’re just using the pressure differential to push them along like a little snaily conveyor belt. Not only is this energy efficient, but the snails able to avoid the perils of crawling along the bottom, where all kinds of obstacles and predators lurk.

Maybe the next incarnation of Real Snail Mail will feature these guys riding tiny jetskis. Why wait for those lazy land snails to deliver messages when you could have a super-efficient water-crawling snail?


One Response to Crawling on water

  1. Kirsten says:

    That is effing sweet. And the snail mail thing is sweet as well. Snails! What CAN’T you do?!?!

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