ROBERT SIEGEL, host:
One of life's great mysteries has at last been solved. It's difficult to watch a cat lapping at a bowl of milk and not wonder how is the milk actually getting from the bowl into the cat? Well, the journal Science has published the conclusive study of how cats drink.
Reporter Geoff Brumfiel has the story.
GEOFF BRUMFIEL: It's not every day you get a chance to reproduce a new scientific result. But this one seemed easy enough. All I needed was my neighbor's cat, Bella.
Hello, Bella. Hello. Come here.
I emphasize it seemed easy.
Come on. You know you want it.
Professor ROMAN STOCKER (Researcher, MIT): You don't induce the cat to drink; you just wait until the cat decides to drink.
BRUMFIEL: Roman Stocker is a researcher at MIT. He and his colleagues spend hours filming - or trying to film - cats lapping.
Prof. STOCKER: The nice thing about it is that the cat laps with an impressive frequency of about four times per second, so if you catch only a few seconds of lapping you have many laps.
BRUMFIEL: Watching in slow motion reveals that cats of all sizes, from tabbies to tigers, have a very elaborate way of drinking. First, they flick their tongue onto the surface of the water and pull it back so quickly, that a little jet of liquid flies into the air. Then, in a flash, they catch the jet in their mouth. What's more, when the researchers crunched the numbers, they found the cats had it down.
Co-author Pedro Reis.
Professor PEDRO REIS (Researcher, MIT): They really know how to time it perfectly, almost as if they're doing all the equations in their head.
BRUMFIEL: The whole system is much more elaborate than dogs, which simply scoop up water with their tongues.
David Hu is a researcher at Georgia Tech.
Professor DAVID HU (Researcher, Georgia Tech): I don't - have no idea why cats just don't do it the ordinary way, but you know that's the weird, interesting thing about biology. What nature does is not necessarily the best way to do things. I think that dogs generally have a better way to do it.
BRUMFIEL: Full disclosure: He owns a poodle. He also recently completed an exhaustive�study�of how dogs shake themselves dry.
All this pet physics might seem a little silly, but it has a point. A lot of researchers are interested in studying the movements of fluids. But modeling drops on a computer can be hard to do.
Prof. HU: These animals are around and they have evolved these great ways to deal with very small quantities of water. How to deal with very small amounts of droplets is a very hard problem, and we're just looking for inspiration wherever we can get it.
BRUMFIEL: Hu thinks the study of cat lapping could lead to new ways of handling fluids. For his part, Stocker thinks that cat tongues might guide the design of ultra flexible robots. And as for my own experiment, I did eventually get my neighbor's cat drinking. But Bella's tongue was too fast for me to see. So if you're trying this at home, you'll need a high-speed camera.
For NPR News, I'm Geoff Brumfiel.
Good girl, Bella. Well done.