User blog:Forestpaw13/"A surprising look at how cats drink"

Found this interesting, and since it's about cats...

A surprising look at how cats drink

One night, Roman Stocker sat at home and watched his cat, Cutta Cutta, lap milk from a bowl.

The Massachusetts Institute of Technology engineering professor began to wonder: How, exactly, did the milk travel from Cutta Cutta's bowl to his mouth?

The answer, based on extensive research published in the journal Science, came as a surprise.

Unlike dogs - who use their tongues like ladles, scooping water into their mouths - cats apply an instinctive understanding of fluid mechanics to take the biggest sips.

"Cats know just when to close their jaw to get the most water," said Pedro Reis, a fluid mechanics expert at MIT who collaborated with Stocker. In fact, he said it's as if "they're doing the equations in their heads."

The experiments involved four MIT scientists, 10 domestic cats, one "robotic cat" forged from a prototype originally built for the International Space Station, four zoo animals and six videos uploaded to YouTube by people who filmed large cats in zoos, on safaris and elsewhere.

To figure out the feline fluid dynamics, the MIT team first made "detailed observations in real cats," Reis said. They filmed Cutta Cutta with a high-speed video camera and filmed nine cats at a nearby shelter. The team saw that the drinking cats' tongues extended toward their bowls in a J-shape. At first, the scientists thought the animals might use their tongues the way dogs do, Reis said.

But only the very tips of the cats' tongues touched the water. Their tongues then moved upward at the blazing-fast speed of more than 3 feet per second, generating a column of liquid. The cats quickly closed their mouths to drink a portion of those columns, the study reported.

The team theorized that the cats maximized the amount of water they consumed in each sip by lapping at a precise speed that balanced two forces: the inertia pulling water upward and the gravity pulling it down.

They tested their hypothesis with their robotic cat and at local zoos. The fluid dynamics equations suggested that a larger cat with a larger tongue would lap less frequently to achieve the needed balance between inertia and gravity. Sure enough, the animals they filmed at the zoos - a lion, a tiger, a jaguar and an ocelot - drank at the slower rates the researchers had predicted.