The way cats drink water turns out to be a more complex process than we thought, according to a paper published in Science on Thursday. When a group of researchers used high-speed imaging to capture video of cats drinking water, they found that cats are, among other things, using only the tip of their tongue to pull water into their mouths from the surface. Once there, they exploit inertia and gravity to hold onto it, and maintain proportionate lapping and swallowing cycles.

It might seem that cats would take advantage of the grain of their tongue that serves them so well in grooming, but the imaging showed that the cats used only the smooth tip to drink. And, unlike dogs, which use their tongue to scoop water, cats' tongues don't even penetrate the surface.

Instead, they get water into their mouths using an almost gecko-like process: their tongue tips shoot out, contact the water surface, adhere to it, and pull up to draw the water into a column that moves into their mouths thanks to sheer inertia. Cats then take advantage of their head orientation and gravity to hold that water in a cavity in their palate, just behind their front teeth. They swallow after somewhere between three and 17 laps.

According to the researchers, it's the cats' lack of cheeks, and the resulting inability to create suction, that restricts them to lapping. Still, cats have managed to adapt pretty admirably, and the authors note that further study of their tongues could be helpful in developing robots with flexible parts and biomechanical models for understanding the behavior of soft tissues.

Science, 2010. DOI: 10.1126/science.1195421 (About DOIs).